3.1.2.1. Provisioning Chassis Slots for Adapter Cards

A chassis slot and card type must be specified and provisioned before an adapter card can be provisioned. A chassis slot is a physical slot designated with an MDA ID. On the 7705 SAR-8, the MDA ID is from 1 to 6. On the 7705 SAR-18, the MDA ID is from 1 to 12 for the MDA slots and from X1 to X4 for the XMDA slots. An adapter card is provisioned when a card designated from the allowed adapter card types is inserted. A preprovisioned adapter card slot can remain empty without conflicting with populated slots.

The adapter cards can be installed in the chassis in any combination that does not exceed the maximum number. However, network applications require at least one network-capable adapter card to be installed as part of the mix.

Once installed and enabled, the system verifies that the installed adapter card type matches the configured parameters. If the parameters do not match, the adapter card remains offline.

3.1.2.2. Maximum Number of Adapter Cards in a Chassis

Note: Unless otherwise specified, references to adapter cards with multiple versions include all versions of the cards.

A maximum of six adapter cards can be installed in the 7705 SAR-8 chassis. The following adapter cards are supported:

A maximum of 12 MDA adapter cards and 4 XMDA adapter cards can be installed in the 7705 SAR-18 chassis. The following adapter cards are supported:

Note: On a 7705 SAR-8 chassis with a CSMv2: a maximum of six 2-port OC3/STM1 Channelized Adapter cards can be installed in MDA slots 1 to 6 if DS3 channelization is being used. If DS1/E1 or DS0 (64 kb/s) channelization is being used, a maximum of four 2-port OC3/STM1 Channelized Adapter cards can be installed in MDA slots 1 to 6. a maximum of six 4-port DS3/E3 Adapter cards can be installed in MDA slots 1 to 6 if DS3/E3 or DS1/E1 channelization is being used. If DS0 (64 kb/s) channelization is being used, a maximum of four 4-port DS3/E3 Adapter cards can be installed in MDA slots 1 to 6. a maximum of four 4-port OC3/STM1 / 1-port OC12/STM4 Adapter cards can be installed in MDA slots 1 to 6 if DS1/E1 channelization is being used. DS0 and DS3/E3 channelization is not supported on the 4-port OC3/STM1 / 1-port OC12/STM4 Adapter card. a maximum of six 6-port Ethernet 10Gbps Adapter cards can be installed in MDA slots 1 to 6. When installed in MDA slot 1 or 2, the 6-port Ethernet 10Gbps Adapter card supports a 10-Gb/s fabric rate. When installed in MDA slots 3 through 6, the aggregate fabric rate is 2.5 Gb/s. On a 7705 SAR-18 chassis: a maximum of twelve 2-port OC3/STM1 Channelized Adapter cards can be installed in MDA slots 1 to 12 if DS3 channelization is being used. If DS1/E1 or DS0 (64 kb/s) channelization is being used, a maximum of four 2-port OC3/STM1 Channelized Adapter cards can be installed in MDA slots 1 to 12. a maximum of twelve 4-port DS3/E3 Adapter cards can be installed in MDA slots 1 to 12 if DS3/E3 or DS1/E1 channelization is being used. If DS0 (64 kb/s) channelization is being used, a maximum of four 4-port DS3/E3 Adapter cards can be installed in MDA slots 1 to 12. a maximum of six 4-port OC3/STM1 / 1-port OC12/STM4 Adapter cards can be installed in MDA slots 1 to 12 if DS1/E1 channelization is being used. DS0 and DS3/E3 channelization is not supported on the 4-port OC3/STM1 / 1-port OC12/STM4 Adapter card. The total number of channel groups that can be configured per card and per node is bound by release-specific system limits. For more information, please contact your Nokia technical support representative.

Note: Because the 6-port E&M Adapter card, 12-port Serial Data Interface card, 8-port Voice & Teleprotection card, 8-port FXO Adapter card, and 6-port FXS Adapter card support access mode only, and the Integrated Services card is a resource card that supports an access functionality only, for network applications, the maximum number of each of these adapter cards that can be installed in a 7705 SAR-8 chassis is 5, and the maximum number that can be installed in a 7705 SAR-18 chassis is 11.

3.1.2.3. Evolution of Ethernet Adapter Cards, Modules, and Platforms

The 7705 SAR hardware components have improved as technology has developed. Table 2 lists the Ethernet adapter cards, modules, and platforms according to their generation. Second-generation (Gen-2) components have additional features, increased card memory and/or improved QoS mechanisms over first-generation (Gen-1) components. Similarly, third-generation (Gen-3) components improve upon second-generation components.

3.1.2.4. Channelized Adapter Card Support

The following cards and modules support channelization down to the DS0 level:

On the 16-port T1/E1 ASAP Adapter card, 32-port T1/E1 ASAP Adapter card, 2-port OC3/STM1 Channelized Adapter card, and 4-port DS3/E3 Adapter card (DS3 ports only), and on the T1/E1 ports of the 4-port T1/E1 and RS-232 Combination module, up to 24 channel groups are supported on a DS1 circuit and up to 32 channel groups on an E1 circuit.

The 12-port Serial Data Interface card supports a single channel group on a channelized V.35 circuit, RS-232 (also known as EIA/TIA-232) circuit, or X.21 circuit. The RS-232 ports on the 4-port T1/E1 and RS-232 Combination module also support a single channel group on a channelized RS-232 circuit.

The 6-port E&M Adapter card supports a single channel group on a channelized E&M voice interface.

The 8-port Voice & Teleprotection card supports a single channel group on a channelized G.703 (codirectional) circuit, an IEEE C37.94 teleprotection interface (TPIF) circuit, FXS circuit, or FXO circuit.

The 8-port FXO Adapter card supports a single channel group on an FXO circuit.

The 6-port FXS Adapter card supports a single channel group on an FXS circuit.

The 4-port OC3/STM1 / 1-port OC12/STM4 Adapter card supports channelization at the DS1/E1 level only.

3.1.3.1. Ethernet

Ethernet ports are supported on the following cards, modules, and platforms:

3.1.3.2. TDM

TDM ports are supported on the following cards, modules, and platforms:

3.1.3.3. DSL

The 6-port DSL Combination module and the 8-port xDSL module (supported on the 7705 SAR-M), and two variants of the 7705 SAR-Wx support DSL.

The 6-port DSL Combination module has six RJ-11 ports on its faceplate. Four of the RJ-11 ports support G.SHDSL.bis pairs, and two RJ-11 ports support xDSL operating in ADSL2,ADSL2+, or VDSL2 mode with no intermixing of DSL types.

The 8-port xDSL module has eight RJ-11 ports on its faceplate that support ADSL2, ADSL2+, or VDSL2 mode with no intermixing of DSL types.

The 7705 SAR-M views the Ethernet link on a DSL module as an Ethernet port. Any services on the 7705 SAR that are supported on an Ethernet port are also supported on the Ethernet link on a DSL module.

Two variants of the 7705 SAR-Wx support one 4-pair xDSL port.

3.1.3.4. GNSS Receiver

The 7705 SAR-H GPS Receiver module is equipped with a GPS RF port for retrieval and recovery of GPS and GLONASS signals. The 7705 SAR-Ax and some variants of the 7705 SAR-Wx are equipped with an integrated GNSS receiver and a GNSS RF port for retrieval and recovery of GPS and GLONASS signals.

The GNSS Receiver card installed in the 7705 SAR-8 or 7705 SAR-18 is equipped with a GNSS RF port for retrieval and recovery of both GPS and GLONASS signals.

Note: GLONASS-only signal recovery is not supported in this release.

3.1.3.5. GPON

The GPON module is a single-port optical network terminal (ONT) that integrates passive optical network (PON) capabilities into the 7705 SAR-M. The GPON module serves as an Ethernet Layer 2 connection point for receiving data from and transmitting data into a GPON network.

The GPON module connects to the 7705 SAR-M as a Gigabit Ethernet port. From an operational perspective, the 7705 SAR-M views the module as one of its Ethernet ports.

3.1.3.6. Multilink Bundles

A multilink bundle is a collection of channels on channelized ports that physically reside on the same adapter card. Multilink bundles are used by providers who offer either bandwidth-on-demand services or fractional bandwidth (DS3) services. Multilink bundles are supported over PPP channels (MLPPP). All member links of an MLPPP group must be of the same type (either E1 or DS1).

The following cards, modules, and platforms support multilink bundles:

3.1.3.7. IMA

The 16-port T1/E1 ASAP Adapter card, 32-port T1/E1 ASAP Adapter card, and the 2-port OC3/STM1 Channelized Adapter card support Inverse Multiplexing over ATM (IMA). IMA is a standard developed to address the increasing need for bandwidth greater than the DS1 or E1 link speeds (1.544 or 2.048 Mb/s, respectively) but less than higher link speeds such as DS3 (44.736 Mb/s). IMA combines the transport bandwidth of multiple DS1 or E1 channels in a logical link (called an IMA group) to provide scalable bandwidth.

3.1.3.8. SONET/SDH

The 4-port OC3/STM1 Clear Channel Adapter card has four hot-pluggable, SFP-based ports that can be independently configured to be SONET (OC3) or SDH (STM1).

The 2-port OC3/STM1 Channelized Adapter card has two hot-pluggable, SFP-based ports that can be configured to be SONET (OC3) or SDH (STM1). All ports on the 2-port OC3/STM1 Channelized Adapter card must be of the same type (either SONET or SDH).

The 4-port OC3/STM1 / 1-port OC12/STM4 Adapter card has four hot-pluggable, SFP-based ports that can be configured to be SONET (OC3 or OC12) or SDH (STM1 or STM4). The card can be configured to be in either 4-port mode or 1-port mode (using the mda-mode command). In 4-port mode, all four ports can be configured as OC3 or STM1. In 1-port mode, only port 1 can be configured as OC12 or STM4. All ports on the 4-port OC3/STM1 / 1-port OC12/STM4 Adapter card must be of the same type (either SONET or SDH).

3.1.3.9. Voice

Voice ports are supported on the following cards:

3.1.3.10. Microwave Link

A microwave link can be configured as a virtual port object on a 7705 SAR-8 or 7705 SAR-18 in order to provide a basic microwave connection or the Microwave Awareness (MWA) capability to an MPR-e node

For more information, see Microwave Link.

3.1.3.11. CLI Identifiers for Adapter Cards, Modules and Platforms

On the CLI, the adapter cards are referred to as MDAs. A port is identified using the format slot/mda/port, where slot identifies the IOM card slot ID (always 1), mda identifies the physical slot in the chassis for the adapter card, and port identifies the physical port on the adapter card; for example, 1/5/1. Adapter cards are configured at the card and port level.

On the fixed platforms, no configuration is required at the adapter card level in order to provision the ports.

On the CLI for the 7705 SAR-A, the slot/mda identifier for T1/E1 ports is 1/2 and for Ethernet ports is 1/1. T1/E1 ports are identified as 1/2/1 through 1/2/8 for the variant of the chassis with T1/E1 ports. Ethernet ports for both variants of the 7705 SAR-A are identified as 1/1/1 through 1/1/12.

On the CLI for the 7705 SAR-Ax, the slot/mda identifier for Ethernet ports is 1/1 and for the GNSS RF port is 1/2.

On the CLI for the 7705 SAR-H, the slot/mda identifier for Ethernet ports is 1/1. The chassis has two slots for modules (the 4-port T1/E1 and RS-232 Combination module, the GPS Receiver module, and the 4-port SAR-H Fast Ethernet module). On the CLI, the slot/mda identifier for a module installed in the first slot position is 1/2 and for a module installed in the second slot position is 1/3. Ethernet ports are identified as 1/1/1 through 1/1/8. Module ports are identified as 1/2/port-num for modules installed in the first slot position and 1/3/port-num for modules installed in the second slot position.

On the CLI for the 7705 SAR-Hc, the slot/mda identifier for Ethernet ports is 1/1 and for RS-232 ports is 1/2. Ethernet ports are identified as 1/1/1 through 1/1/6 and RS-232 ports are identified as 1/2/1 and 1/2/2.

On the CLI for the 7705 SAR-M, the slot/mda identifier for T1/E1 ports is 1/2 and for Ethernet ports is 1/1. For those variants of the chassis that have a module slot, the slot/mda identifier for the module on the CLI is 1/3. The 7705 SAR-M variants with module slots support the following modules: GPON module, 6-port DSL Combination module, 8-port xDSL module, CWDM OADM module, 2-port 10GigE (Ethernet) module, and 6-port SAR-M Ethernet module. T1/E1 ports are identified as 1/2/1 through 1/2/16 for those variants of the chassis with T1/E1 ports. Ethernet ports for all variants of the 7705 SAR-M are identified as 1/1/1 through 1/1/7. Those variants of the chassis that have module slots identify module ports as 1/3/port-num.

On the CLI for the 7705 SAR-W, the slot/mda identifier for the Ethernet ports is 1/1. Ethernet ports are identified as 1/1/1 through 1/1/5. The 7705 SAR-W also has an internal (virtual) port used for in-band Ethernet management connection. The virtual port is identified as vrtl-mgmt on the CLI and as 1/1/6 via SNMP.

On the CLI for the 7705 SAR-Wx, the slot/mda identifier for the Ethernet ports is 1/1 and 1/2 for the xDSL port. Ethernet ports for the Ethernet-only variant and the Ethernet and PoE+ variant are identified as 1/1/1 through 1/1/5. For the variant supporting Ethernet ports and an xDSL port, the Ethernet ports are identified as 1/1/1 through 1/1/4 and the DSL port is identified as 1/2/1 through 1/2/4.

On the CLI for the 7705 SAR-X, the slot/mda identifier is specified as 1 for T1/E1 ports and 2 or 3 for Ethernet ports. The port number is specified as a variable that can have a value from 1 to 8 for T1/E1 ports or 1 to 7 for Ethernet ports, depending on how the port is configured.

For the 16-port T1/E1 ASAP Adapter card, 32-port T1/E1 ASAP Adapter card, and 4-port DS3/E3 Adapter card, the channel-group-id identifies the DS1 or E1 channel group; for example, 1/5/1.20. For the 2-port OC3/STM1 Channelized Adapter card, the channel-group-id identifies the DS1, E1, or DS3 channel group. For the 4-port OC3/STM1 / 1-port OC12/STM4 Adapter card, the channel-group-id identifies the DS1 or E1 channel group. For the 12-port Serial Data Interface card, the channel-group-id identifies the V.35, RS-232, or X.21 channel group; only one channel group per port is supported on the card, so the format would be 1/1/1.1.

For the 6-port E&M Adapter card, the channel-group-id identifies the E&M voice channel group; only one channel group per port is supported on the card, so the format would be 1/1/1.1. For the 8-port Voice & Teleprotection card, the 8-port FXO Adapter card, and the 6-port FXS Adapter card, the channel-group-id identifies the DS0 channel group; only one channel group per port is supported on the card, so the format would be 1/1/1.1.

For the 4-port T1/E1 and RS-232 Combination module, the channel-group-id identifies the DS1 or E1 channel group for the T1/E1 ports (for example, 1/2/3.5) or the channel group for the RS-232 ports (for example, 1/2/2.1).

On the CLI for the 2-port 10GigE (Ethernet) Adapter card or 2-port 10GigE (Ethernet) module, for virtual-port configuration, an Ethernet port is identified as v-port.

The following output examples display the administrative and operational states of adapter cards for all platforms.

For the 7705 SAR-8 with a CSMv2:

For the 7705 SAR-18:

For the 7705 SAR-A:

For the 7705 SAR-Ax:

For the 7705 SAR-H:

For the 7705 SAR-Hc:

For the 7705 SAR-M:

For the 7705 SAR-W:

For a 7705 SAR-Wx Ethernet variant:

For a 7705 SAR-Wx Ethernet with xDSL variant:

For a 7705 SAR-X:

3.1.3.12. Access, Network, and Hybrid Ports

All ports must be set to access (customer-facing), network, or hybrid mode. When the mode is configured on a port, the appropriate encapsulation type must be configured to distinguish the services on the port or channel (for access mode), or to define the transport mode (for network mode).

For the 16-port T1/E1 ASAP Adapter card, version 2, 32-port T1/E1 ASAP Adapter card, and 4-port DS3/E3 Adapter card, the card must be enabled to support a set of software services before the encapsulation type is configured. This support is enabled using the mda-mode command (see the mda-mode command in the Configuration Command Reference section):

The default modes are listed in Table 6. All channel groups on a port must either be all access or all network channel groups; there cannot be a mix. When the first channel group is configured, all other channel groups on that port must be set to the same mode. To change modes, all channel groups must first be shut down.

3.1.3.12.2. Access Ports

Access ports on the following can be configured for PPP/MLPPP channel groups:

1. 2-port OC3/STM1 Channelized Adapter card
2. 16-port T1/E1 ASAP Adapter card
3. 32-port T1/E1 ASAP Adapter card
4. T1/E1 ports on the 4-port T1/E1 and RS-232 Combination module (on 7705 SAR-H)
5. T1/E1 ports on the 7705 SAR-A (variants with T1/E1 ports)
6. T1/E1 ports on the 7705 SAR-M (variants with T1/E1 ports)
7. T1/E1 ports on the 7705 SAR-X

Customer IP traffic can be transported directly over PPP or MLPPP links. Access ports on the following can also be configured for TDM to transport 2G traffic from BTSs or ATM/IMA to transport 3G UMTS traffic from Node Bs:

1. 2-port OC3/STM1 Channelized Adapter card
2. 16-port T1/E1 ASAP Adapter card
3. 32-port T1/E1 ASAP Adapter card
4. T1/E1 ports on the 7705 SAR-M (variants with T1/E1 ports)

In access mode, PPP channels can be associated with n × DS0 channel groups. Although multiple PPP channel groups are supported per T1/E1 port, all the channel groups must be the same encapsulation type. For example, if one channel group on a given port is set for ipcp encapsulation, another channel group on the same port cannot be set to cem. If MLPPP channels are used, an MLPPP channel group fills up an entire DS1 or E1 link.

The 2-port OC3/STM1 Channelized Adapter card supports ipcp encapsulation of PPP/MLPPP packets for transport over an Ipipe.

The data ports on the 12-port Serial Data Interface card and the RS-232 ports on the 4-port T1/E1 and RS-232 Combination module provide transport between two data devices. Each data stream that is transported across the network can be mapped into a TDM pseudowire (Cpipe) for transport across an MPLS network. The other end can terminate either on another 7705 SAR or a multiplexer capable of terminating the pseudowire.

The 12-port Serial Data Interface card supports frame-relay encapsulation of data on V.35 and X.21 channel groups for transport over a frame relay pseudowire (Fpipe) or IP interworking pseudowire (Ipipe). The 12-port Serial Data Interface card also supports ipcp and cisco-hdlc encapsulation of PPP and Cisco HDLC packets, respectively, for transport over an Ipipe.

The 12-port Serial Data Interface card and the 4-port T1/E1 and RS-232 Combination module can also be part of a system architecture where a circuit originates on an SDI port on the 7705 SAR, transits over an MPLS network, and terminates on a 3600 MainStreet node connected to a 7705 SAR over a T1/E1 connection. In addition to the MPLS network functionality, the 12-port Serial Data Interface card and the 4-port T1/E1 and RS-232 Combination modulec an also operate in a TDM SAP-to-SAP mode where the other SAP can be another port on the 12-port Serial Data Interface card or on a T1/E1 ASAP card.

Access ports on the 8-port Ethernet Adapter card, 8-port Gigabit Ethernet Adapter card, 6-port Ethernet 10Gbps Adapter card, 10-port 1GigE/1-port 10GigE X-Adapter card, the Packet Microwave Adapter card, and the xDSL ports on the 7705 SAR-Wx, can transport traffic from sources such as e911 locators, site surveillance equipment, VoIP phones, and video cameras. The Ethernet traffic is transported over the PSN using Ethernet VLLs.

Note: For information on VLLs, refer to the 7705 SAR Services Guide, “VLL Services”.

A microwave link from a Packet Microwave Adapter card port in access mode can peer with user equipment such as a node B or MPR-e radio. The 7705 SAR-8 and the 7705 SAR-18 treat the microwave access link as a normal SAP into a service such as Epipe, Ipipe, or VPLS/VPRN.

Voice ports on the 6-port E&M Adapter card, 8-port Voice & Teleprotection card, and 8-port FXO Adapter card provide voiceband transmission between two analog devices over a digital network. A 7705 SAR-8 or 7705 SAR-18 terminates the voice circuit and then transmits the data over a TDM-based network interface (SAP-to-SAP) or an MPLS packet-based network interface (SAP-to-SDP). For standard TDM, a T1 or E1 interface is used to transmit the data across the network.

For MPLS, any network interface (that is, Ethernet, T1/E1 MLPPP, or OC3/STM1) can be used. The traffic originating from the 6-port E&M Adapter card, 8-port Voice & Teleprotection card, or 8-port FXO Adapter card can be mapped into a TDM pseudowire (Cpipe) for transport across the MPLS network. The 6-port E&M Adapter card, 8-port Voice & Teleprotection card, and 8-port FXO Adapter card support one TDM pseudowire per port.

The voice circuit can terminate on another 7705 SAR-8 or 7705 SAR-18 over the MPLS or T1/E1 TDM connection, on other TDM-capable equipment (such as a 3600 MainStreet node) over a T1/E1 TDM connection, or on other MPLS-capable equipment over an MPLS pseudowire emulation (PWE) connection. A 3600 MainStreet or 1511 MAX can also connect to an FXO port on the 8-port Voice & Teleprotection card.

Voice ports on a 6-port FXS Adapter card can be configured for a PBX application or a PLAR (hotline) application. For a PBX application, the voice circuits are terminated on an FXO interface at a 7705 SAR hub location that is connected to a PBX. The FXO interface can be provided by either an 8-port FXO Adapter card or 8-port Voice & Teleprotection card that is installed in a 7705 SAR-8 or 7705 SAR-18 chassis at the 7705 SAR hub location. For a PLAR application, voice circuits are terminated on an FXS interface on either another 6-port FXS Adapter card or an 8-port Voice & Teleprotection card that is installed in a 7705 SAR-8 or 7705 SAR-18 chassis located at a remote location, or terminated on a 3600 MainStreet or 1511 MAX. A hotline call can also originate from a 3600 MainStreet or 1511 MAX and terminate on an FXS interface on a 6-port FXS Adapter card (or on an FXS interface on an 8-port Voice & Teleprotection card.

SONET/SDH ports in access mode on a 4-port OC3/STM1 Clear Channel Adapter card can be configured for ATM (such as for 3G UMTS Node Bs).

The DS3/E3 clear channel access ports on the 4-port DS3/E3 Adapter card can be configured for ATM PW services (categories CBR, VBR-rt, VBR-nrt, UBR, and UBR+MCR), for TDM PW services to transport 2G traffic from BTSs, and for frame relay PW service.

Access ports on the 2-port OC3/STM1 Channelized Adapter card can be configured for TDM to transport 2G traffic from BTSs or ATM/IMA to transport 3G UMTS traffic from Node Bs. Access ports on the 4-port OC3/STM1 / 1-port OC12/STM4 Adapter card can only be configured for TDM.

All member links of the IMA group must reside on the same card. The 2G traffic is transported across the PSN encapsulated in a TDM VLL. The 3G traffic is transported using ATM VLLs.

For PPP/MLPPP channel groups, the encapsulation type must be ipcp. For Ethernet VLLs, the encapsulation type can be null, dot1q, or qinq. For TDM VLLs, the encapsulation type must be cem. For ATM VLLs, the encapsulation type must be atm.

3.1.3.12.2.1. H-QoS for Access Egress Ethernet Ports

To support hierarchical QoS (H-QoS) on second-generation Ethernet adapter cards, the 7705 SAR supports the configuration of one aggregate CIR rate for all the unshaped 4-priority access egress Ethernet SAPs on a port, thereby ensuring that all the unshaped SAPs can compete with the shaped SAPs on the port for fabric bandwidth. Use the config>port>ethernet>access>egress>unshaped-sap-cir command to set the aggregate CIR rate.

Third-generation (Gen-3) Ethernet adapter cards and platforms have 4-priority schedulers, and all SAPs are shaped SAPs. See Table 2 for a list of first-, second-, and third-generation adapter cards, modules, and platforms. Refer to the “QoS for Gen-3 Adapter Cards and Platforms” section in the 7705 SAR Quality of Service Guide for more information on 4-priority schedulers for Gen-3 hardware.

Ports on the 4-port SAR-H Fast Ethernet module do not support H-QoS.

For more information on H-QoS and on shaped and unshaped Ethernet SAPs, refer to the “Per-SAP Aggregate Shapers (H-QoS)” section in the 7705 SAR Quality of Service Guide.

3.1.3.12.3. Network Ports

Network uplinks can be configured as standalone PPP ports, or MLPPP can be configured on T1/E1 ports or channels. All member links of an MLPPP group must be of the same type (either E1 or Ds1).

The following cards, modules, and platforms support multilink bundles:

1. T1/E1 ports on the 7705 SAR-A (variants with T1/E1 ports)
2. T1/E1 ports on the 7705 SAR-M (variants with T1/E1 ports)
3. T1/E1 ports on the 7705 SAR-X
   The following must have all member links of an MLPPP bundle configured on the same card or module:
   1. 16-port T1/E1 ASAP Adapter card
   2. 32-port T1/E1 ASAP Adapter card
   3. T1/E1 ports on the 4-port T1/E1 and RS-232 Combination module (on 7705 SAR-H)
   The following must have all member links of an MLPPP bundle configured on the same card or module, and on the same port:
   1. 2-port OC3/STM1 Channelized Adapter card
   2. 4-port OC3/STM1 / 1-port OC12/STM4 Adapter card

Ethernet ports on the 8-port Ethernet Adapter card, 8-port Gigabit Ethernet Adapter card, 6-port Ethernet 10Gbps Adapter card, 10-port 1GigE/1-port 10GigE X-Adapter card, and Packet Microwave Adapter card can be configured for network mode. Ethernet uplinks can be used as a cost-effective alternative to T1/E1 links.

On the 2-port 10GigE (Ethernet) Adapter card and 2-port 10GigE (Ethernet) module, the Ethernet ports and the v-port can be configured for network mode only.

A microwave link from a Packet Microwave Adapter card port in network mode provides a network uplink to an MPR-e radio. The 7705 SAR-8 or 7705 SAR-18 treats the microwave link as a Gigabit Ethernet network link with MPLS always running over it. All standard MPLS/IP functions available on a network port or SDP are also available on the microwave link.

For network uplinks on the 4-port OC3/STM1 Clear Channel Adapter card and 4-port OC3/STM1 / 1-port OC12/STM4 Adapter card, a clear channel port can be configured for POS to connect to the packet network. PPP can be enabled on a port by setting the encapsulation type to ppp-auto.

On the 4-port DS3/E3 Adapter card, a DS3/E3 clear channel port can be configured for PPP as the network uplink. The encapsulation type must be set to ppp-auto.

The 7705 SAR supports both copper and fiber uplinks.

3.1.3.12.3.1. Aggregate CIR for Unshaped VLANs on Network Egress Ethernet Ports

The 7705 SAR supports the configuration of one aggregate CIR rate for all the unshaped network egress Ethernet VLANs on a port, thereby ensuring that all the unshaped VLANs can compete with the shaped VLANs (that is, network interfaces) at the port level for egress bandwidth. Use the config>port>ethernet> network>egress>unshaped-if-cir command to set the aggregate CIR rate.

Note: The unshaped-if-cir command does not apply to Gen-3 Ethernet adapter cards and platforms, except for network egress in hybrid mode. In this case, the shaper-if-cir command applies.

For more information on shaped and unshaped Ethernet VLANs, refer to the “Per-VLAN Network Egress Shapers” and “QoS for Gen-3 Adapter Cards and Platforms” sections in the 7705 SAR Quality of Service Guide.

3.1.3.12.4. Hybrid Ports

Hybrid ports are supported on Ethernet ports, where they provide the capabilities and features of access and network mode ports on a per-VLAN basis. The following services support hybrid port functionality: Epipe PW, Ipipe PW, IP-VPN, VPLS, and IES.

For ingress traffic, QoS and traffic management on a hybrid port behaves in the same way for access and network port modes. Refer to the 7705 SAR Quality of Service Guide, “QoS for Hybrid Ports on Gen-2 Hardware” and “QoS for Gen-3 Adapter Cards and Platforms” for details.

Network VLANs on a hybrid port provide OAM down MEP support, as well as port loopback support (in line mode with latched timers only).

The following hardware supports hybrid ports:

1. 6-port SAR-M Ethernet module (except for the Fast Ethernet ports (ports 1 and 2))
2. 6-port Ethernet 10Gbps Adapter card
3. 8-port Gigabit Ethernet Adapter card
4. 10-port 1GigE/1-port 10GigE X-Adapter card (only in 10-port 1GigE mode)
5. Packet Microwave Adapter card (only in Ethernet port mode (not mw-link mode))
6. 7705 SAR-A Ethernet ports (except for the Fast Ethernet ports (ports 9 to 12))
7. 7705 SAR-Ax Ethernet ports
8. 7705 SAR-M Ethernet ports
9. 7705 SAR-H Ethernet ports
10. 7705 SAR-Hc Ethernet ports
11. 7705 SAR-W Ethernet ports
12. 7705 SAR-Wx Ethernet ports
13. 7705 SAR-X Ethernet ports

In some scenarios, combining the access and network capabilities under the same port is beneficial. A typical scenario is shown in Figure 1, where a single port hosts both access-side services and a traffic management model together with network-side IP/MPLS routing and switching capabilities simultaneously.

In this scenario, a network interface is configured to ensure connectivity between the cell site 7705 SAR and the aggregation site 7705 SAR. The network interface is used for all IP/MPLS traffic and is bound to VLAN-1. Another VLAN (VLAN-2) is configured to bind the management traffic of a microwave radio (an MPR-e) to an access-side service such as an Ethernet PW or VPLS. For security reasons, many mobile operators prefer to transport management traffic of network elements under a service construct as opposed to basic GRT-based routing. To accommodate this preference, an access-side service and a network interface can be configured to coexist on the same port when the port is configured for hybrid mode.

Figure 1:  Hybrid Port Application 

3.2.1.1. MLPPP Overview

Multilink point-to-point protocol (MLPPP) is a method of splitting, recombining, and sequencing packets across multiple logical data links. MLPPP is defined in the IETF RFC 1990, The PPP Multilink Protocol (MP).

MLPPP allows multiple PPP links to be bundled together, providing a single logical connection between two routers. Data can be distributed across the multiple links within a bundle to achieve high bandwidth. As well, MLPPP allows for a single frame to be fragmented and transmitted across multiple links. This capability allows for lower latency and also for a higher maximum receive unit (MRU).

Multilink protocol is negotiated during the initial LCP option negotiations of a standard PPP session. A system indicates to its peer that it is willing to perform MLPPP by sending the MP option as part of the initial LCP option negotiation.

The system indicates the following capabilities.

Once MLPPP has been successfully negotiated, the sending system is free to send PDUs encapsulated and/or fragmented with the MP header.

MP introduces a new protocol type with a protocol ID (PID) of 0x003d. Figure 2 and Figure 3 show the MLPPP fragment frame structure. Framing to indicate the beginning and end of the encapsulation is the same as that used by PPP and described in RFC 1662, PPP in HDLC-like Framing.

MP frames use the same HDLC address and control pair value as PPP: Address – 0xFF and Control – 0x03. The 2-octet protocol field is also structured the same way as in PPP encapsulation.

Figure 2:  MLPPP 24-bit Fragment Format 

Figure 3:  MLPPP 12-bit Fragment Format 

The required and default format for MP is the 24-bit format. During the LCP state, the 12-bit format can be negotiated. The 7705 SAR is capable of supporting and negotiating the alternate 12-bit frame format.

The maximum differential delay supported for MLPPP is 25 ms.

3.2.1.2. Protocol Field (PID)

The protocol field is two octets. Its value identifies the datagram encapsulated in the Information field of the packet. In the case of MP, the PID also identifies the presence of a 4-octet MP header (or 2-octet, if negotiated).

A PID of 0x003d identifies the packet as MP data with an MP header.

The LCP packets and protocol states of the MLPPP session follow those defined by PPP in RFC 1661. The options used during the LCP state for creating an MLPPP NCP session are described in the sections that follow.

3.2.1.3. B&E Bits

The B&E bits are used to indicate the start and end of a packet. Ingress packets to the MLPPP process will have an MTU, which may or may not be larger than the maximum received reconstructed unit (MRRU) of the MLPPP network. The B&E bits manage the fragmentation of ingress packets when the packet exceeds the MRRU.

The B-bit indicates the first (or beginning) packet of a given fragment. The E-bit indicates the last (or ending) packet of a fragment. If there is no fragmentation of the ingress packet, both B&E bits are set to true (=1).

3.2.1.4. Sequence Number

Sequence numbers can be either 12 or 24 bits long. The sequence number is 0 for the first fragment on a newly constructed bundle and increments by one for each fragment sent on that bundle. The receiver keeps track of the incoming sequence numbers on each link in a bundle and reconstructs the desired unbundled flow through processing of the received sequence numbers and B&E bits. For a detailed description of the algorithm, refer to RFC 1990.

3.2.1.5. Information Field

The Information field is zero or more octets. The Information field contains the datagram for the protocol specified in the protocol field.

The MRRU will have the same default value as the MTU for PPP. The MRRU is always negotiated during LCP.

3.2.1.6. Padding

On transmission, the Information field of the ending fragment may be padded with an arbitrary number of octets up to the MRRU. It is the responsibility of each protocol to distinguish padding octets from real information. Padding must only be added to the last fragment (E-bit set to true).

3.2.1.7. FCS

The FCS field of each MP packet is inherited from the normal framing mechanism from the member link on which the packet is transmitted. There is no separate FCS applied to the reconstituted packet as a whole if it is transmitted in more than one fragment.

3.2.1.8. LCP

The Link Control Protocol (LCP) is used to establish the connection through an exchange of configure packets. This exchange is complete, and the LCP opened state entered, once a Configure-Ack packet has been both sent and received.

LCP allows for the negotiation of multiple options in a PPP session. MP is somewhat different from PPP, and therefore the following options are set for MP and are not negotiated:

Any non-LCP packets received during this phase must be silently discarded.

3.2.1.9. T1/E1 Link Hold Timers

T1/E1 link hold timers (or MLPPP link flap dampening) guard against the node reporting excessive interface transitions. Timers can be set to determine when link up and link down events are advertised; that is, up-to-down and down-to-up transitions of the interface are not advertised to upper layer protocols (are dampened) until the configured timer has expired.

3.2.2.1. QoS in MC-MLPPP

MC-MLPPP on the 7705 SAR supports scheduling based on multi-class implementation. Instead of the standard profiled queue-type scheduling, an MC-MLPPP encapsulated access port performs class-based traffic servicing. The four MC-MLPPP classes are scheduled in a strict priority fashion, as shown in Table 7.

For example, if a packet is sent to an MC-MLPPP class 3 queue and all other queues are empty, the 7705 SAR fragments the packet according to the configured fragment size and begins sending the fragments. If a new packet arrives at an MC-MLPPP class 2 queue while the class 3 fragment is still being serviced, the 7705 SAR finishes sending any fragments of the class 3 packet that are on the wire, then holds back the remaining fragments in order to service the higher-priority packet.

The fragments of the first packet remain at the top of the class 3 queue. For packets of the same class, MC-MLPPP class queues operate on a first-in, first-out basis.

The user configures the required number of MLPPP classes to use on a bundle. The forwarding class of the packet, as determined by the ingress QoS classification, is used to determine the MLPPP class for the packet. The mapping of forwarding class to MLPPP class is a function of the user-configurable number of MLPPP classes. The mapping for 4-class, 3-class, and 2-class MLPPP bundles is shown in Table 8.

If one or more forwarding classes are mapped to a queue, the scheduling priority of the queue is based on the lowest forwarding class mapped to it. For example, if forwarding classes 0 and 7 are mapped to a queue, the queue is serviced by MC-MLPPP class 3 in a 4-class bundle model.

3.2.3.1. SLARP

The 7705 SAR supports only the SLARP keepalive protocol.

For the SLARP keepalive protocol, each system sends the other a keepalive packet at a user configurable interval. The default interval is 10 seconds. Both systems must use the same interval to ensure reliable operation. Each system assigns sequence numbers to the keepalive packets it sends, starting with zero, independent of the other system. These sequence numbers are included in the keepalive packets sent to the other system. Also included in each keepalive packet is the sequence number of the last keepalive packet received from the other system, as assigned by the other system. This number is called the returned sequence number. Each system keeps track of the last returned sequence number it has received. Immediately before sending a keepalive packet, the system compares the sequence number of the packet it is about to send with the returned sequence number in the last keepalive packet it has received. If the two differ by 3 or more, it considers the line to have failed, and will not route higher-level data across it until an acceptable keepalive response is received.

3.2.5.1. Network Synchronization on T1/E1, Ethernet, GPON, and DSL Ports

Line timing mode provides physical layer timing (Layer 1) that can be used as an accurate reference for nodes in the network. This mode is immune to any packet delay variation (PDV) occurring on a Layer 2 or Layer 3 link. Physical layer timing provides the best synchronization performance through a synchronization distribution network.

On the 7705 SAR-A variant with T1/E1 ports, line timing is supported on T1/E1 ports. Line timing is also supported on all synchronous Ethernet ports on both 7705 SAR-A variants. Synchronous Ethernet is supported on the XOR ports (1 to 4), configured as either RJ-45 ports or SFP ports. Synchronous Ethernet is also supported on SFP ports 5 to 8. Ports 9 to 12 do not support synchronous Ethernet and, therefore, do not support line timing.

On the 7705 SAR-Ax, line timing is supported on all Ethernet ports.

On the 7705 SAR-H, line timing is supported on:

On the 7705 SAR-Hc, line timing is supported on all Ethernet ports.

On the 7705 SAR-M (variants with T1/E1 ports), line timing is supported on T1/E1 ports. Line timing is also supported on all RJ-45 Ethernet ports and SFP ports on the 7705 SAR-M (all variants).

On the 7705 SAR-W, line timing is supported on:

On the 7705 SAR-Wx, line timing is supported on:

On the 7705 SAR-X, line timing is supported on T1/E1 ports and Ethernet ports.

In addition, line timing is supported on the following modules when they are installed in chassis variants with module slots:

On the 7705 SAR-8 and 7705 SAR-18, line timing is supported on:

Synchronous Ethernet is a variant of line timing and is automatically enabled on ports and SFPs that support it. The operator can select a synchronous Ethernet port as a candidate for the timing reference. The recovered timing from this port is then used to time the system. This ensures that any of the system outputs are locked to a stable, traceable frequency source.

3.2.5.2. Network Synchronization on SONET/SDH Ports

Each SONET/SDH port can be independently configured to be loop-timed (recovered from an Rx line) or node-timed (recovered from the SSU in the active CSM).

A SONET/SDH port’s receive clock rate can be used as a synchronization source for the node.

3.2.5.3. Network Synchronization on DS3/E3 Ports

Each clear channel DS3/E3 port on a 4-port DS3/E3 Adapter card can be independently configured to be loop-timed (recovered from an Rx line), node-timed (recovered from the SSU in the active CSM), or differential-timed (derived from the comparison of a common clock to the received RTP timestamp in TDM pseudowire packets). When a DS3 port is channelized, each DS1 or E1 channel can be independently configured to be loop-timed, node-timed, or differential-timed (differential timing on DS1/E1 channels is supported only on the first three ports of the card). When not configured for differential timing, a DS3/E3 port can be configured to be a timing source for the node.

3.2.5.4. Network Synchronization on DS3 CES Circuits

Each DS3 CES circuit on a 2-port OC3/STM1 Channelized Adapter card card can be loop-timed (recovered from an Rx line) or free-run (timing source is from its own clock). A DS3 circuit can be configured to be a timing source for the node.

3.2.5.5. Network Synchronization on T1/E1 Ports and Circuits

Each T1/E1 port can be independently configured for loop-timing (recovered from an Rx line) or node-timing (recovered from the SSU in the active CSM).

In addition, T1/E1 CES circuits on the following can be independently configured for adaptive timing (clocking is derived from incoming TDM pseudowire packets):

T1/E1 CES circuits on the following can be independently configured for differential timing (recovered from RTP in TDM pseudowire packets):

A T1/E1 port can be configured to be a timing source for the node.

Note: Adaptive timing and differential timing are not supported on DS1 or E1 channels that have CAS signaling enabled.

3.2.8.1. Ethernet OAM Overview

802.3ah Clause 57 (EFM OAM) defines the Operations, Administration, and Maintenance (OAM) sublayer, which is a link level Ethernet OAM that is supported on 7705 SAR Ethernet ports and DSL ports configured as network or access ports. It provides mechanisms for monitoring link operations such as remote fault indication and remote loopback control. EFM OAM is not supported on the 7705 SAR-M GPON module.

Ethernet OAM gives network operators the ability to monitor the status of Ethernet links and quickly determine the location of failing links or fault conditions.

Because some of the sites where the 7705 SAR will be deployed will only have Ethernet uplinks, this OAM functionality is mandatory. For example, mobile operators must be able to request remote loopbacks from the peer router at the Ethernet layer in order to debug any connectivity issues. EFM OAM provides this capability.

EFM OAM is supported on network and access Ethernet and DSL ports, and is configured at the port level. The access ports can be configured to tunnel the OAM traffic originated by the far-end devices.

EFM OAM has the following characteristics.

The following EFM OAM functions are supported:

For information on Epipe service, refer to the 7705 SAR Services Guide, “Ethernet VLL (Epipe) Services”, and the 7705 SAR OAM and Diagnostics Guide, “Ethernet OAM Capabilities”.

3.2.8.2. CRC (Cyclic Redundancy Check) Monitoring

CRC errors typically occur when Ethernet links are compromised due to optical fiber degradation, weak optical signals, bad optical connections, or problems on a third-party networking element. As well, higher-layer OAM options such as EFM and BFD may not detect errors and trigger appropriate alarms and switchovers if the errors are intermittent, since this does not affect the continuous operation of other OAM functions.

CRC error monitoring on Ethernet ports allows degraded links to be alarmed or failed in order to detect network infrastructure issues, trigger necessary maintenance, or switch to redundant paths. This is achieved through monitoring ingress error counts and comparing them to the configured error thresholds. The rate at which CRC errors are detected on a port can trigger two alarm states. Crossing the configured signal degrade (SD) threshold (sd-threshold) causes an event to be logged and an alarm to be raised, which alerts the operator to a potential issue on a link. Crossing the configured signal failure (SF) threshold (sf-threshold) causes the affected port to enter the operationally down state, and causes an event to be logged and an alarm to be raised.

The CRC error rates are calculated as M×10E-N, which is the ratio of errored frames allowed for total frames received. The operator can configure both the threshold (N) and a multiplier (M). If the multiplier is not configured, the default multiplier (1) is used. For example, setting the SD threshold to 3 results in a signal degrade error rate threshold of 1×10E-3 (1 errored frame per 1000 frames). Changing the configuration to an SD threshold of 3 and a multiplier of 5 results in a signal degrade error rate threshold of 5×10E-3 (5 errored frames per 1000 frames). The signal degrade error rate threshold must be lower than the signal failure error rate threshold because it is used to notify the operator that the port is operating in a degraded but not failed condition.

A sliding window (window-size) is used to calculate a statistical average of CRC error statistics collected every second. Each second, the oldest statistics are dropped from the calculation. For example, if the default 10-s sliding window is configured, at the 11th second the oldest second of statistical data is dropped and the 11th second is included. This sliding average is compared against the configured SD and SF thresholds to determine if the error rate over the window exceeds one or both of the thresholds, which will generate an alarm and log event.

When a port enters the failed condition as a result of crossing an SF threshold, the port is not automatically returned to service. Because the port is operationally down without a physical link, error monitoring stops. The operator can enable the port by using the shutdown and no shutdown port commands or by using other port transition functions such as clearing the MDA (clear mda command) or removing the cable. A port that is down due to crossing an SF threshold can also be re-enabled by changing or disabling the SD threshold. The SD state is self-clearing, and it clears if the error rate drops below 1/10th of the configured SD rate.

Note: CRC monitoring is not supported on GPON or DSL ports.

3.2.8.3. Remote Loopback

EFM OAM provides a link-layer frame loopback mode, which can be controlled remotely.

To initiate a remote loopback, the local EFM OAM client sends a loopback control OAMPDU by enabling the OAM remote loopback command. After receiving the loopback control OAMPDU, the remote OAM client puts the remote port into local loopback mode.

OAMPDUs are slow protocol frames that contain appropriate control and status information used to monitor, test, and troubleshoot OAM-enabled links.

To exit a remote loopback, the local EFM OAM client sends a loopback control OAMPDU by disabling the OAM remote loopback command. After receiving the loopback control OAMPDU, the remote OAM client puts the port back into normal forwarding mode.

When a port is in local loopback mode (the far end requested an Ethernet OAM loopback), any packets received on the port will be looped back, except for EFM OAMPDUs. No data will be transmitted from the node; only data that is received on the node will be sent back out.

When the node is in remote loopback mode, local data from the CSM is transmitted, but any data received on the node is dropped, except for EFM OAMPDUs.

Remote loopbacks should be used with caution; if dynamic signaling and routing protocols are used, all services go down when a remote loopback is initiated. If only static signaling and routing is used, the services stay up. On the 7705 SAR, the Ethernet port can be configured to accept or reject the remote-loopback command.

3.2.8.4. 802.3ah OAMPDU Tunneling and Termination for Epipe Service

Customers who subscribe to Epipe service might have customer equipment running 802.3ah at both ends. The 7705 SAR can be configured to tunnel EFM OAMPDUs received from a customer device to the other end through the existing network using MPLS or GRE, or to terminate received OAMPDUs at a network or an access Ethernet port.

Note: This feature applies only to port-based Epipe SAPs because 802.3ah runs at port level, not at VLAN level.

While tunneling offers the ability to terminate and process the OAM messages at the head-end, termination on the first access port at the cell site can be used to detect immediate failures or can be used to detect port failures in a timelier manner. The user can choose either tunneling or termination, but not both at the same time.

In Figure 6, scenario 1 shows the termination of received EFM OAMPDUs from a customer device on an access port, while scenario 2 shows the same thing except for a network port. Scenario 3 shows tunneling of EFM OAMPDUs through the associated Ethernet PW. To configure termination (scenario 1), use the config>port>ethernet>efm-oam>no shutdown command.

Figure 6:  EFM Capability on the 7705 SAR 

3.2.8.5. Dying Gasp

Dying gasp is used to notify the far end that EFM-OAM is disabled or shut down on the local port. The dying gasp flag is set on the OAMPDUs that are sent to the peer. The far end can then take immediate action and inform upper layers that EFM-OAM is down on the port.

When a dying gasp is received from a peer, the node logs the event and generates an SNMP trap to notify the operator.

3.2.9.1. Line and Internal Ethernet Loopbacks

A line loopback loops frames received on the corresponding port back towards the transmit direction. Line loopbacks are supported on ports configured for access or network mode.

Similarly, a line loopback with MAC addressing loops frames received on the corresponding port back towards the transmit direction, and swaps the source and destination MAC addresses before transmission. See MAC Swapping for more information.

An internal loopback loops frames from the local router back to the framer. This is usually referred to as an equipment loopback. The transmit signal is looped back and received by the interface. Internal loopbacks are supported on ports configured in access mode.

If a loopback is enabled on a port, the port mode cannot be changed until the loopback has been disabled.

A port can support only one loopback at a time. If a loopback exists on a port, it must be disabled or the timer must expire before another loopback can be configured on the same port. EFM-OAM cannot be enabled on a port that has an Ethernet loopback enabled on it. Similarly, an Ethernet loopback cannot be enabled on a port that has EFM-OAM enabled on it.

When an internal loopback is enabled on a port, autonegotiation is turned off silently. This is to allow an internal loopback when the operational status of a port is down. Any user modification to autonegotiation on a port configured with an internal Ethernet loopback will not take effect until the loopback is disabled.

The loopback timer can be configured from 30 s to 86400 s. All non-zero timed loopbacks are turned off automatically under the following conditions: an adapter card reset, DSL module reset, GPON module reset, an activity switch, or timer expiry. Line or internal loopback timers can also be configured as a latched loopback by setting the timer to 0 s, or as a persistent loopback with the persistent keyword. Latched and persistent loopbacks are enabled indefinitely until turned off by the user. Latched loopbacks survive adapter card resets and activity switches, but are lost if there is a system restart. Persistent loopbacks survive adapter card resets and activity switches and can survive a system restart if the admin-save or admin-save-detail command was executed prior to the restart. Latched loopbacks (untimed) and persistent loopbacks can be enabled only on Ethernet access ports.

Persistent loopbacks are the only Ethernet loopbacks saved to the database by the admin-save and admin-save-detail commands.

An Ethernet port loopback may interact with other features. See Interaction of Ethernet Port Loopback with Other Features for more information.

3.2.9.2. CFM Loopbacks for OAM on Ethernet Ports

This section contains information on the following topics:

3.2.9.2.1. CFM Loopback Overview

Connectivity fault management (CFM) loopback support for loopback messages (LBMs) on Ethernet ports allows operators to run standards-based Layer 1 and Layer 2 OAM tests on ports receiving unlabeled packets.

The 7705 SAR supports CFM MEPs associated with different endpoints (that is, spoke SDP Down MEPs, network interface facility MEPs, and SAP Up and SAP Down MEPs). In addition, for traffic received from an uplink (network ingress), the 7705 SAR supports CFM LBM for both labeled and unlabeled packets. CFM loopbacks are applied to the Ethernet port.

Refer to the 7705 SAR OAM and Diagnostics Guide, “Ethernet OAM Capabilities”, for information on CFM MEPs.

Figure 7 shows an application where an operator leases facilities from a transport network provider in order to transport traffic from a cell site to their MTSO. The operator leases a certain amount of bandwidth between the two endpoints (the cell site and the MTSO) from the transport provider, who offers Ethernet Virtual Private Line (EVPL) or Ethernet Private Line (EPL) PTP service. Before the operator offers services on the leased bandwidth, the operator runs OAM tests to verify the SLA. Typically, the transport provider (MEN provider) requires that the OAM tests be run in the direction of (towards) the first Ethernet port that is connected to the transport network. This is done in order to eliminate the potential effect of queuing, delay, and jitter that may be introduced by a spoke SDP or SAP.

Figure 7:  CFM Loopback on Ethernet Ports 

Figure 7 shows an Ethernet verifier at the MTSO that is directly connected to the transport network (in front of the 7750 SR). Thus, the Ethernet OAM frames are not label-encapsulated. Given that Ethernet verifiers do not support label operations and the transport provider mandates that OAM tests be run between the two hand-off Ethernet ports, the verifier cannot be relocated behind the 7750 SR node at the MTSO. Therefore, CFM loopback frames received are not MPLS-encapsulated, but are simple Ethernet frames where the type is set to CFM (dot1ag or Y.1731).

3.2.12.1. MTU Configuration Overview

Because of the services overhead (that is, pseudowire/VLL, MPLS tunnel, dot1q/qinq and dot1p overhead), it is crucial that configurable variable frame size be supported for end-to-end service delivery.

Observe the following general rules when planning your service and physical Maximum Transmission Unit (MTU) configurations.

For more information, refer to the “MTU Settings” section in the 7705 SAR Services Guide. To configure various MTU points, use the following commands:

Figure 8:  MTU Points on the 7705 SAR 

Frame size configuration is supported for an Ethernet port configured as an access or a network port.

For an Ethernet adapter card that does not support jumbo frames, all frames received at an ingress network or access port are policed against 1576 bytes (1572 + 4 bytes of FCS), regardless of the port MTU. Any frames longer than 1576 bytes are discarded and the “Too Long Frame” and “Error Stats” counters in the port statistics display are incremented. See Jumbo Frames for more information.

At network egress, Ethernet frames are policed against the configured port MTU. If the frame exceeds the configured port MTU, the “Interface Out Discards” counter in the port statistics is incremented.

When the network group encryption (NGE) feature is used, additional bytes due to NGE packet overhead must be considered. Refer to the “NGE Packet Overhead and MTU Considerations” section in the 7705 SAR Services Guide for more information.

3.2.12.2. IP Fragmentation

IP fragmentation is used to fragment a packet that is larger than the MTU of the egress interface, so that the packet can be transported over that interface.

For IPv4, the router fragments or discards the IP packets based on whether the DF (Do not fragment) bit is set in the IP header. If the packet that exceeds the MTU cannot be fragmented, the packet is discarded and an ICMP message “Fragmentation Needed and Don’t Fragment was Set” is sent back to the source IP address.

For IPv6, the router cannot fragment the packet so must discard it. An ICMP message “Packet too big” is sent back to the source node.

As a source of self-generated traffic, the 7705 SAR can perform packet fragmentation.

Fragmentation can be enabled for GRE tunnels. Refer to the “GRE Fragmentation” section in the 7705 SAR Services Guide for more information.

3.2.12.3. Jumbo Frames

Jumbo frames are supported on Ethernet ports except on the 8-port Ethernet Adapter card (version 1).

The maximum MTU size for a jumbo frame on the 7705 SAR is 9732 bytes. The maximum MTU for a jumbo frame may vary depending on the Ethernet encapsulation type, as shown in Table 11. The calculations of the other MTU values (service MTU, path MTU, and so on) are based on the port MTU. The values in Table 11 are also maximum receive unit (MRU) values. MTU values are user-configured values. MRU values are the maximum MTU value that a user can configure on an adapter card that supports jumbo frames.

For an Ethernet Adapter card, all frames received at an ingress network or access port are policed against the MRU for the ingress adapter card, regardless of the configured MTU. Any frames larger than the MRU are discarded and the “Too Long Frame” and “Error Stats” counters in the port statistics display are incremented.

At network egress, frames are checked against the configured port MTU. If the frame exceeds the configured port MTU and the DF bit is set, then the “MTU Exceeded” discard counter will be incremented on the ingress IP interface statistics display, or on the MPLS interface statistics display if the packet is an MPLS packet.

For example, on adapter cards that do not support an MTU greater than 2106 bytes, fragmentation is not supported for frames greater than the maximum supported MTU for that card (that is, 2106 bytes). If the maximum supported MTU is exceeded, the following occurs.

Jumbo frames offer better utilization of an Ethernet link because as more payload is packed into an Ethernet frame of constant size, the ratio of overhead to payload is minimized.

From the traffic management perspective, large payloads may cause long delays, so a balance between link utilization and delay must be found. For example, for ATM VLLs, concatenating a large number of ATM cells when the MTU is set to a very high value could generate a 9-kbyte ATM VLL frame. Transmitting a frame that large would take more than 23 ms on a 3-Mb/s policed Ethernet uplink.

3.2.12.4. Default Port MTU Values

Table 12 displays the default and maximum port MTU values that are dependent upon the port type, mode, and encapsulation type.

Note: The 7705 SAR now supports a lower IP MTU value of 128 bytes (from the original 512-byte minimum). The IP MTU is derived from the port MTU configuration for network ports. This lower IP MTU is supported only on Ethernet encapsulated ports. Refer to the 7705 SAR Services Guide, “Bandwidth Optimization for Low-speed Links” for information.

For more information, refer to the “MTU Settings” section in the 7705 SAR Services Guide.

3.2.13.1. LAG Overview

The 7705 SAR supports Link Aggregation Groups (LAGs) based on the IEEE 802.1ax standard (formerly 802.3ad). Link aggregation provides:

In the 7705 SAR implementation, all links must operate at the same speed.

Packet sequencing must be maintained for any given session. The hashing algorithm deployed by Nokia routers is based on the type of traffic transported to ensure that all traffic in a flow remains in sequence while providing effective load sharing across the links in the LAG. See LAG and ECMP Hashing for more information.

LAGs must be statically configured or formed dynamically with Link Aggregation Control Protocol (LACP). See LACP and Active/Standby Operation for information on LACP.

All Ethernet-based supported services can benefit from LAG, including:

LAGs are supported on access, network, and hybrid ports. A LAG can be in active/active mode or in active/standby mode for access, network, or hybrid ports. Active/standby mode is a subset of active/active mode if subgroups are enabled.

LAGs are supported on access ports on the following:

LAGs are supported on network ports on the following:

LAGs are supported on hybrid ports on the following:

On access ports, a LAG supports active/active and active/standby operation. For active/standby operation the links must be in different subgroups. Links can be on the same platform or adapter card/module or distributed over multiple components. Load sharing is supported among the active links in a LAG group.

On network ports, a LAG supports active/active and active/standby operation. For active/standby operation the links must be in different subgroups. Links can be on the same platform or adapter card/module or distributed over multiple components. Load sharing is supported among the active links in a LAG group. Any tunnel type (for example, IP, GRE, or MPLS) transporting any service type, any IP traffic, or any labeled traffic (LER, LSR) can use the LAG load-sharing, active/active, and active/standby functionality.

LAGs are supported on network 1+0 microwave links. Ports that are in a microwave link can be added to the same LAG as ports that are not in a microwave link. Ports belonging to a microwave link must have limited autonegotiation enabled before the link can be added to a LAG.

A LAG that contains ports in a microwave link must have LACP enabled for active/standby operation. Static LAG configuration (without LACP) is not supported for active/standby LAGs with microwave-enabled ports.

On hybrid ports, a LAG supports active/active and active/standby operation. For active/standby operation the links must be in different subgroups. Links can be on the same platform or adapter card/module or distributed over multiple components. Load sharing is supported among the active links in a LAG group.

A LAG group with assigned members can be converted from one mode to another as long as the number of member ports are supported in the new mode and the ports all support the new mode, none of the members belong to a microwave link, and the LAG group is not associated with a network interface or a SAP.

Note: For details on LAG scale per platform or adapter card, contact your Nokia Technical support representative.

A subgroup is a group of links within a LAG. On access, network, or hybrid ports, a LAG can have a maximum of four subgroups and a subgroup can have links up to the maximum number supported on the LAG. The LAG is active/active if there is only one sub-group and is active/standby if there is more than one subgroup.

When configuring a LAG, most port features (port commands) can only be configured on the primary member port. The configuration, or any change to the configuration, is automatically propagated to any remaining ports within the same LAG. Operators cannot modify the configurations on non-primary ports. For more information, see Configuring LAG Parameters.

If the LAG has one member link on a first- or second-generation (Gen-1 or Gen-2) Ethernet adapter card, and the other link on a third-generation (Gen-3) Ethernet adapter card or platform, a mix-and-match scenario exists for traffic management on the LAG SAP. In this case, all QoS parameters for the LAG SAP are configured but only those parameters applicable to the active member link are used. See LAG Support on Mixed-Generation Hardware for more information.

Configuring a multiservice site (MSS) aggregate rate can restrict the use of LAG SAPs. For more information, refer to the “MSS and LAG Interaction on the 7705 SAR-8 and 7705 SAR-18” section in the 7705 SAR Quality of Service Guide.

3.2.13.2. LACP and Active/Standby Operation

On access, network, and hybrid ports, where multiple links in a LAG can be active at the same time, normal operation is that all non-failing links are active and traffic is load-balanced across all the active links. In some cases, however, it is desirable to have only some of the links active and the other links kept in standby mode. The Link Aggregation Control Protocol (LACP) is used to make the selection of the active links in a LAG predictable and compatible with any vendor equipment. The mechanism is based on the IEEE 802.1ax standard so that interoperability is ensured.

Note: LACP cannot be configured for static LAG. For more information on static LAG, see Static LAG (Active/Standby LAG Operation without LACP).

LACP is disabled by default and therefore must be enabled on the LAG if required. LACP can be used in either active mode or passive mode. The mode must match with connected CE devices for proper operation. For example, if the LAG on the 7705 SAR end is configured to be active, the CE end must be passive.

Figure 9 shows the interconnection between a DSLAM and a LAG aggregation node. In this configuration, LAG is used to protect against hardware failure. If the active link goes down, the link on standby takes over (see Figure 10). The links are distributed across two different adapter cards to eliminate a single point of failure.

Figure 9:  LAG on Access Interconnection 

Figure 10:  LAG on Access Failure Switchover 

LACP handles active/standby operation of LAG subgroups as follows.

Log events and traps are generated at both the LAG and link level to indicate any LACP changes. See the TIMETRA-LAG-MIB for details.

3.2.13.3. QoS Adaptation for LAG on Access

QoS on access port LAGs (access ports and hybrid ports in access mode) is handled differently from QoS on network port LAGs. Based on the configured hashing, traffic on a SAP can be sent over multiple LAG ports or can use a single port of a LAG. There are two user-selectable adaptive QoS modes (distribute and link) that allow the user to determine how the configured QoS rate is distributed to each of the active LAG port SAP queue schedulers, SAP schedulers (H-QoS), and MSS schedulers. These modes are:

Table 13 shows examples of rate and bandwidth distributions based on the adapt-qos mode configuration.

The following restrictions apply to ingress MSS LAG adaptive QoS (distribute mode).

The following restrictions apply to egress MSS LAG.

The following limitations apply to adaptive QoS (distribute mode).

3.2.13.4. Access Ingress Fabric Shaping

In order to avoid traffic congestion and ease the effects of possible bursts, a fabric shaper is implemented on each adapter card. Traffic being switched to a LAG SAP on an access interface goes through fabric shapers that are either in aggregate mode or destination mode. When in destination mode, the multipoint shaper is used to set the rate on all adapter cards. For more information on the modes used in fabric shaping, refer to the 7705 SAR Quality of Service Guide, “Configurable Ingress Shaping to Fabric (Access and Network)”.

Note: Even though the multipoint shaper is used to set the fabric shaping rate for traffic switched to a LAG SAP, it is the per-destination unicast counters that are incremented to show the fabric statistics rather than the multipoint counter. Only the fabric statistics of the active port of the LAG are incremented, not the standby port.

3.2.13.5. Hold-down Timers

Hold-down timers control how quickly a LAG responds to operational port state changes. The following timers are supported:

3.2.13.6. Multi-Chassis LAG

Multi-chassis LAG (MC-LAG) is a redundancy feature on the 7705 SAR, useful for nodes that are taken out of service for maintenance, upgrades, or relocation. MC-LAG also provides redundancy for incidents of peer nodal failure. Refer to the “Multi-Chassis LAG Redundancy” section in the 7705 SAR Basic System Configuration Guide.

3.2.13.7. Static LAG (Active/Standby LAG Operation without LACP)

Some Layer 2 capable network equipment devices support LAG protected links in an active/standby mode but without LACP. This is commonly referred to as static LAG. In order to interwork with these products, the 7705 SAR supports configuring LAG without LACP.

LACP provides a standard means of communicating health and status information between LAG peers. If LACP is not used, the peers must be initially configured in a way that ensures that the ports on each end are connected and communicating. Otherwise, LAG will not be active. Which LAG peer is made active is a local decision. If the port priority settings are the same for all ports, it is possible that the two ends will select ports on different physical links and LAG will not be active. Decide the primary link by setting the port priority for the LAG on each peer to ensure that the active ports on each end coincide with the same physical link.

The key parameters for configuring static LAG are selection-criteria (set to best-port) and standby-signaling (set to power-off). The selection criteria is used to determine which selection algorithm decides the primary port (the active port in a no-fault condition). It is always the subgroup with the best-port (the highest-priority port - lowest configured value) that is chosen as the active subgroup. The selection criteria must be set to best-port before standby signaling can be placed in power-off mode. Once the selection criteria is set to best-port, setting the standby-signaling parameter to power-off causes the transmitters on the standby ports to be powered down.

After a switchover caused by a failure on the active link, the transmitters on the standby link are powered on. The switch time for static LAG is typically longer than it is with LACP, due to the time it takes for the transmitters to come up and transmission to be established. When the fault is restored, static LAG causes a revertive switch to take place. The revertive switch is of shorter duration than the initial switchover since the system is able to prepare the other side for the switch and initiate the switchover once it is ready.

Note: Since the transmitters on the standby link are off, it is not possible for the LAG to respond to a physical disconnect (fault) on the standby link. This means that it is possible to have a failure on the active link result in a switch to a failed standby link.

3.2.13.8. LAG Support on Mixed-Generation Hardware

This section contains information on the following topics:

3.2.13.8.1. LAG Configuration at SAP Level

The 6-port Ethernet 10Gbps Adapter card and the 7705 SAR-X are third-generation (Gen-3) hardware components. All other Ethernet cards are second-generation (Gen-2) adapter cards, except the 8-port Ethernet Adapter card, which is a first-generation (Gen-1) adapter card. See Table 2 for a list of first-, second-, and third-generation Ethernet adapter cards, ports, and platforms.

The 7705 SAR supports mix-and-match traffic management (TM) across LAG members, where one member is a port on a Gen-3 adapter card or platform and the other member is a port on either a Gen-2 or Gen-1 adapter card or platform. Mix-and-match LAG does not apply to the 7705 SAR-X because it has only Gen-3 Ethernet ports.

For mix-and-match LAG TM scenarios, the 7705 SAR supports a generic QoS configuration, where the operator can configure all the settings available on each generation adapter card, but it is the card responsible for transporting traffic that determines which settings are applicable. That is, only the settings that apply to the active member port are used. The only exception is if there is a Gen-1 adapter card in the mix. In this case scheduling-mode cannot be changed to 16-priority scheduling. Only 4-priority scheduling is applicable.

For example, configuring scheduling-mode applies to Gen-2 adapter card SAPs but does not apply to the Gen-3 adapter card SAPs because Gen-3 cards support only one scheduling mode (4-priority), which is its implicit (default) scheduler mode and is not configurable. In another example, although per-SAP (second-tier) shaper rates can be configured for Gen-2 and Gen-3 cards, they will not be applied to Gen-1 cards.

Since it cannot be known whether SAP traffic rides over a Gen-2 or a Gen-3 adapter card and whether both adapter cards support H-QoS (tier 2, per-SAP shapers), the operator can choose to configure per-SAP aggregate CIR and PIR shaper rates. When the active link is on a Gen-2- or Gen-3-based port, per-SAP aggregate CIR and PIR rates are both used to enforce shaper rates, except when the active link is on a Gen-3-based port and traffic is in the network egress direction. In this case, only the PIR portion of the per-SAP aggregate rate is used to enforce shaper rates.

In the following descriptions of LAG configuration, scheduler-mode, agg-rate, and cir-rate refer to SAP configuration, as shown below for an Epipe SAP. Similar commands exist for SAPs in other services as well as for egress traffic.

Example:

config>service>epipe>sap lag-id>ingress#

   scheduler-mode {4-priority | 16-priority} 

   agg-rate-limit agg-rate [cir cir-rate] 

Note: The SAP identifier in the previous command has a lag-id (LAG SAP), not a port-id (regular SAP). A LAG SAP references two ports (one active and one standby), but only one port at a time carries traffic. The agg-rate is a PIR rate.

For information on traffic management for Gen-3 adapter cards and platforms, refer to the “QoS for Gen-3 Adapter Cards and Platforms” section in the 7705 SAR Quality of Service Guide.

For mix-and-match LAG configurations, the following behaviors apply.

1. The configured aggregate rate on the LAG SAP is used to dictate the per-SAP aggregate rate on the active LAG port, regardless of which generation of adapter card is used (Gen-3 or Gen-2) or the configured scheduler mode. On a Gen-2 adapter card, the aggregate rate only applies when the port is in 16-priority scheduler mode. This behavior implies the following points.
   1. The scheduler mode can be set to 16-priority or 4-priority. When servicing packets, the Gen-2-based datapath uses the configured scheduler mode (16-priority or 4-priority), while the Gen-3-based datapath always uses 4-priority scheduling.
   2. When the traffic is transported over a Gen-3-based port (that is, the active link is on a Gen-3-based adapter card), the aggregate rate (agg-rate) is used to enforce a maximum shaper rate, as is the aggregate rate CIR (cir-rate).
   3. When the active link is on a Gen-2-based adapter card, both aggregate rate CIR and PIR (cir-rate and agg-rate) are used. The aggregate rate (PIR) enforces the per-SAP bandwidth limit, and the CIR is used to identify in-profile and out-of-profile packets for aggregate scheduling purposes.
   4. When the active link is on a Gen-1-based adapter card, aggregate rate CIR and PIR do not apply.

In addition, the following items describe mix-and-match LAG configuration behavior (that is, how the LAG SAP settings are applied or ignored depending on the active member port).

1. For a LAG SAP, scheduler-mode, agg-rate, and cir-rate are all configurable on a per-SAP basis, regardless of the LAG member port combination (that is, both Gen-2 ports, both Gen-3 ports, or a Gen-2-/Gen-3 port mix).
2. Scheduler-mode can be set to 4-priority or 16-priority, regardless of the LAG member port combination, except when one member is a port on a Gen-1 adapter card. In this case, only 4-priority scheduling is available.
3. Agg-rate and cir-rate can be set whether scheduler-mode is set to 4-priority or 16-priority.
4. The configured scheduler-mode applies to Gen-2-based LAG member ports only, and is not used for Gen-3-based LAG member ports. Gen-3 cards always use 4-priority scheduler mode and Gen-1 cards always use 4-priority scheduler mode. The unshaped-sap-cir keyword does not apply to Gen-3 SAPs because Gen-3 SAPs are all shaped SAPs.
5. If scheduler-mode is 4-priority on the LAG SAP, where the LAG has one Gen-1-based or Gen-2-based port member and one Gen-3-based port member, the following points apply.
   1. The Gen-1-based or Gen-2-based adapter card is configured with 4-priority scheduling, while agg-rate and cir-rate are not applied, and H-QoS is not enabled.
   2. The Gen-3-based adapter card is configured with agg-rate and cir-rate, while scheduler-mode is ignored.
   3. When LAG active/standby switching occurs from an active Gen-3-based port to an active Gen-1-based or Gen-2-based port, traffic management is changed from a 4-priority scheduler with H-QoS to a 4-priority scheduler without H-QoS that behaves like an unshaped SAP.
   4. For the reverse case, when LAG active/standby switching occurs from an active Gen-1-based or Gen-2-based port to an active Gen-3-based port, traffic management is changed from a 4-priority scheduler without H-QoS to a 4-priority scheduler with H-QoS.
6. If scheduler-mode is 16-priority on the LAG SAP, where the LAG has one Gen-2-based port member and one Gen-3-based port member, the following points apply.
   1. The Gen-2-based adapter card is configured with 16-priority scheduling mode, agg-rate and cir-rate. This means that H-QoS is enabled.
   2. The Gen-3-based adapter card is configured with agg-rate and cir-rate, while scheduler-mode is ignored.
   3. When LAG active/standby switching occurs from an active Gen-3-based port to an active Gen-2-based port, traffic management is changed from a 4-priority scheduler with H-QoS using the agg-rate and cir-rate, to a 16-priority scheduler with H-QoS using the agg-rate and the cir-rate (that is, from 4-priority (Gen-3) mode to 16-priority mode for shaped SAPs).
   4. For the reverse case, when LAG active/standby switching occurs from an active Gen-2-based port to an active Gen-3-based port, traffic management is changed from a 16-priority scheduler with H-QoS using the agg-rate and the cir-rate, to a 4-priority (Gen-3) scheduler with H-QoS enabled using the agg-rate and the cir-rate.
7. If scheduler-mode is 16-priority mode on the LAG SAP, the combination of a Gen-1-based port with a Gen-2-based or Gen-3-based port is blocked because Gen-1 adapter cards do not support 16-priority mode. The only valid option for this combination of ports is 4-priority scheduling mode.

Lastly, for LAG on access ports, the primary port configuration settings are applied to both the primary and secondary LAG ports. Therefore, in order to support unshaped SAPs when the primary port is a Gen-3-based port and the secondary port is a Gen-2-based port, configuring the unshaped-sap-cir on the Gen-3-based port is allowed, even though it does not apply to the Gen-3-based port. This is because unshaped-sap-cir is needed by the secondary Gen-2-based port when it becomes the active port. The full command is config>port>ethernet>access>egress> unshaped-sap-cir cir-rate.

3.2.13.8.2. LAG Configuration at Port Level

The 7705 SAR allows all configurations on Gen-1, Gen-2, and Gen-3 ports, even if some or all of the configuration is not applicable to all the ports. The software uses only the settings that are applicable to the particular port and ignores those that are not applicable. Any change to the primary LAG member configuration propagates to all non-primary ports.

Table 14 lists the port commands that can be affected by LAG configuration, indicates the command’s applicability to Gen-1, Gen-2, and Gen-3 ports, and describes the LAG behavior for mixed LAG configuration.

Note: For LAG on network ports, the egress-rate, unshaped-if-cir, and network-queue policy can only be configured on the primary LAG port and this configuration is propagated to the other LAG members.

Table 14:  Port Command Applicability for LAG Configurations on Mixed-Generation Hardware  

CLI Command	Gen-1 Port	Gen-2 Port	Gen-2 Port on Module 1	Gen-3 Port	Configuration Behavior
unshaped-if-cir	Supported 2	Supported 2	Supported 2	Supported 3	Allowed on Gen-1, Gen-2, and Gen-3 hardware, but not on Fast Ethernet ports. All port members of the same LAG must have the same value.
unshaped-sap-cir	N/A	Supported	Supported	N/A	Allowed on Gen-2 and Gen-3 hardware, but not on Gen-1 hardware. This means LAGs with Gen-1 members and Gen-2 or Gen-3 members do not allow the unshaped-sap-cir command to be configured to a non-zero value on Gen-2 or Gen-3 ports.  LAGs with Gen-2 and Gen-3 members are allowed if all member ports have the same unshaped-sap-cir value. Change the value only on the primary member. The value is propagated to all other members.
shaper-policy	N/A	Supported	Supported	Supported	Allowed on Gen-2 and Gen-3 hardware, but not on Gen-1 hardware. The same restrictions described above for the unshaped-sap-cir command for LAG members apply.
cbs	Supported	Supported	Supported	Supported	Allowed on all hardware generations. All LAG members must have the same value. Change the value only on the primary member. The value is propagated to all other members.
src-pause	Enable or disable	Enable or disable	Disable	Enable or disable	Allowed to change enable/disable on Gen-1, Gen-2, and Gen-3 hardware, except for a Gen-3 port on a 6-port SAR-M Ethernet Module, where only the no src-pause command is supported and cannot be changed. All LAG members must have same value.  Change the value only on the primary member. The value is propagated to all other members.
include-fcs	N/A	Enable or disable	Always enabled	Enable or disable	Allowed on Gen-2 and Gen-3 hardware, but not on Gen-1 hardware. The same restrictions described above for the unshaped-sap-cir command for LAG members apply.
scheduler-mode (for port)	Profile or 4-priority	16-priority	16-priority	4-priority	Allowed to configure per-port independently, whether the port is a standalone or an active/standby member. There is no propagation among ports within the same LAG.

Notes:

1. Refers to the 6-port SAR-M Ethernet module.
2. Not supported on Fast Ethernet ports.
3. If the port is in network mode, the unshaped-if-cir command can be configured but does not take effect. If the port is in hybrid mode, the command takes effect.

As indicated in Table 14, each generation of adapter card uses its own configured scheduler mode, or uses the only command option available for Gen-2 and Gen-3 adapter cards, whereas Gen-1 adapter cards use their own adapter card configuration. For example, on a LAG where:

1. one member link is on Gen-2 hardware
   1. this port uses 16-priority scheduler mode, which is the default mode and cannot be changed
2. one member link is on Gen-3 hardware
   1. this port uses 4-priority (Gen-3) scheduler mode, which is the default mode and cannot be changed
3. one member link is on Gen-1 hardware
   1. this port uses its configured scheduler mode (profiled or 4-priority), which is dictated via the configuration applied to the port

3.2.14.1. Per-Flow Hashing

The 7705 SAR supports per-flow hashing for LAG and ECMP. Per-flow hashing uses information in a packet as an input to the hash function, ensuring that any given traffic flow maps to the same egress LAG port or ECMP path.

Depending on the type of traffic that needs to be distributed in an ECMP or LAG path, different variables are used as the input to the hashing algorithm that determines the selection of the next hop (ECMP) or port (LAG). The hashing result can be changed using the options described in Per-Service Hashing, LSR Hashing, Layer 4 Load Balancing, TEID Hashing for GTP-encapsulated Traffic, and Entropy Labels.

Table 15 summarizes the possible inputs to the hashing algorithm for ECMP and LAG.

Fragmented packets cannot use Layer 4 UDP/TCP ports or tunnel endpoint IDs (TEIDs). The datapath looks at IP source address and destination address only, even if configured to use Layer 4 UDP/TCP ports or TEID.

In Table 15, the hashing inputs in the Service ID column and the inputs in the other columns are mutually exclusive. Where checkmarks appear on both the per-service and per-flow sides of the table, refer to the table note in the Service ID column to determine when per-service hashing is used.

3.2.14.2. Per-Service Hashing

The 7705 SAR supports load balancing based on service ID, as shown in Table 15, The 7705 SAR uses the service ID as the input to the hash function. Per-service and per-flow hashing are mutually exclusive features.

For IPv4 and IPv6 routed traffic under ECMP operation, the service ID is used as the hashing input for Layer 3 traffic going to a Layer 3 spoke SDP interface. Otherwise, per-flow load balancing is used.

For Epipe and VPLS services under LAG operation, the per-service-hashing command and the l4-load-balancing and teid-load-balancing commands are mutually exclusive. Load balancing via per-service hashing is configured under the config>service> epipe>load-balancing and config>service>vpls> load-balancing contexts.

Note: Prior to Release 8.0.R4 of the 7705 SAR, load balancing for an Epipe service was implicitly defaulted to be enabled (that is, hashing was always on the service ID). Release 8.0.R4 adds the per-service-hashing command, which is disabled by default. The per-service-hashing command must be explicitly enabled if pre-Release 8.0.R4 behavior is needed. Starting with Release 8.0.R4, unless per-service-hashing is enabled, a 4-byte hash value will be appended to internal overhead for VPLS multicast traffic at ingress. The egress internal hash value is discarded at egress before scheduling. Therefore, shaping rates at access and network ingress and for fabric policies may need to be adjusted accordingly. In addition, the 4-byte internal hash value may be included in any affected statistics counters.

3.2.14.3. LSR Hashing

LSR hashing operates on the label stack and can also include hashing on the IP header if the packet is an IPv4 packet. The label-IP hashing algorithm can also include the Layer 4 header and the TEID field. The default hash is on the label stack only. IPv4 is the only IP hashing supported on a 7705 SAR LSR.

When a 7705 SAR is acting as an LSR, it considers a packet to be IP if the first nibble following the bottom of the label stack is 4 (IPv4). This allows the user to include an IP header in the hashing routine at an LSR in order to spray labeled IP packets over multiple equal-cost paths in ECMP in an LDP LSP and/or over multiple links of a LAG group in all types of LSPs.

Other LSR hashing options include label stack profile options on the significance of the bottom-of-stack label (VC label), the inclusion or exclusion of the ingress port, and the inclusion or exclusion of the system IP address.

Note: The global IF index is no longer a hash input for LSR ECMP load balancing. It has been replaced with the use-ingress-port configurable option in the lsr-load-balancing command. As well, the default treatment of the MPLS label stack has changed to focus on the bottom-of-stack label (VC label). In previous releases, all labels had equal influence.

LSR load balancing is configured using the config>system>lsr-load-balancing or config>router>if>lsr-load-balancing command. Configuration at the router interface level overrides the system-level configuration for the specified interface.

If an ELI is found in the label stack, the entropy label is used as the hash result. Hashing continues based on the configuration of label-only (lbl-only), label-IP (lbl-ip), or label-IP with Layer 4 header and TEID (lbl-ip-l4-teid) options.

3.2.14.4. Layer 4 Load Balancing

The IP Layer 4 load-balancing option includes the TCP/UDP source and destination port numbers in addition to the source and destination IP addresses in per-flow hashing of IP packets. By including the Layer 4 information, a source address/destination address default hash flow can be subdivided into multiple finer-granularity flows if the ports used between a source address and destination address vary.

Layer 4 load balancing is configured at the system level using the config>system>l4-load-balancing command. It can also be configured at the router interface level or the service interface level (IES and VPRN). Configuration at the router interface or service interface level overrides the system-level configuration for the specified interface or service.

For LSR LDP ECMP, Layer 4 load balancing is configured using the lbl-ip-l4-teid option in the lsr-load-balancing command at the system level or router interface level. Configuration at the router interface level overrides the system-level configuration for the specified interface.

Layer 4 load balancing can also be configured at the service level for Epipe and VPLS services. Layer 4 load balancing at the service level is not impacted by Layer 4 load balancing at the system, router interface, or service interface levels.

3.2.14.5. TEID Hashing for GTP-encapsulated Traffic

GTP is the GPRS (general packet radio service) tunneling protocol. The tunnel endpoint identifier (TEID) is a field in the GTP header. TEID hashing can be enabled on Layer 3 interfaces. The hash algorithm identifies the GTP-U protocol by checking the UDP destination port (2152) of an IP packet to be hashed. If the value of the port matches, the packet is assumed to be GTP-U. For GTPv1 packets, the TEID value from the expected header location is then included in the hash. For GTPv2 packets, the TEID flag value in the expected header is additionally checked to verify whether the TEID is present. If the TEID is present, it is included in the hash algorithm inputs.

TEID load balancing is configured at the router interface level using the config> router>if>teid-load-balancing command. It can also be configured at the IES or VPRN service interface level.

For LSR LDP ECMP, TEID load balancing is configured using the lbl-ip-l4-teid option in the lsr-load-balancing command at the system level or router interface level. Configuration at the router interface level overrides the system-level configuration for the specified interface.

TEID load balancing can also be configured at the service level for Epipe and VPLS services. TEID load balancing at the service level is not impacted by TEID load balancing at the router interface or service interface levels.

3.2.14.6. Entropy Labels

The 7705 SAR supports MPLS entropy labels on RSVP-TE LSPs, as per RFC 6790. The entropy label provides greater granularity for load balancing on an LSR where load balancing is typically based on the MPLS label stack.

If an ELI is found in the label stack, the entropy label is used as the hash result and hashing continues based on the configuration of label-only (lbl-only) or label-IP (lbl-ip) options. For information on the behavior of LSR hashing when entropy label is enabled, see LSR Hashing.

To support entropy labels on RSVP-TE LSPs:

At the eLER, use the config>router>rsvp>entropy-label-capability command to enable entropy label capability on RSVP-TE LSPs.

At the iLER, use the entropy-label command to enable the insertion of the entropy label into the label stack. The command is found under the Epipe config>service>epipe>spoke-sdp command, and under the VPLS config>service>vpls>spoke-sdp and mesh-sdp commands.

For details on entropy labels, refer to the “MPLS Entropy Labels” section in the 7705 SAR MPLS Guide.

3.2.15.1. APS Overview

Automatic Protection Switching (APS) allows users to protect a SONET/SDH port or link with a backup (protection) facility of the same speed but from a different adapter card. APS provides protection against a port, signal, or adapter card failure. The 7705 SAR supports 1+1 APS protection in compliance with GR-253-CORE and ITU-T Recommendation G.841 to provide SONET/SDH carrier-grade reliability. All SONET/SDH paths and channels within a SONET/SDH port are protected.

When APS is enabled, the 7705 SAR constantly monitors the health of the APS links, APS ports, and APS-equipped adapter cards. If the signal on the active (working) port degrades or fails, the network proceeds through a predefined sequence of steps to transfer (or switch over) traffic processing to the protection port. This switchover is done very quickly to minimize lost traffic. Traffic is streamed from the protection port until the working port fault is cleared, at which time the traffic may optionally be reverted to the working port.

The 7705 SAR supports 1+1 single-chassis APS (SC-APS) and 1+1 multi-chassis APS (MC-APS). In an SC-APS group, both the working and protection circuit must be configured on the same node, whereas an MC-APS group can be on two separate nodes, providing protection from node failure in addition to protection from link and hardware failure.

Unidirectional and bidirectional modes are supported:

For SC-APS and MC-APS with MEF 8 services where the remote device performs source MAC validation, the MAC address of the channel group in each of the redundant interfaces may be configured to the same MAC address using the mac CLI command.

3.2.15.2. SC-APS

In an SC-APS group, both the working and protection circuits terminate on the same node. SC-APS is supported in unidirectional or bidirectional mode on:

SC-APS with TDM access is supported on DS3, DS1, E1, and DS0 (64 kb/s) channels.

The working and protection circuits of an SC-APS group must be on two ports on different adapter cards.

Figure 11 shows an SC-APS group with physical port and adapter card failure protection. Figure 12 shows a packet network using SC-APS.

Figure 11:  SC-APS with Physical Port and Adapter Card Protection 

Figure 12:  SC-APS Application 

3.2.15.3. MC-APS

MC-APS extends the functionality offered by SC-APS to include protection against 7705 SAR node failure. MC-APS is supported in bidirectional mode on:

MC-APS with TDM access is supported on DS3, DS1, E1, and DS0 (64 kb/s) channels. TDM SAP-to-SAP with MC-APS is not supported.

With MC-APS, the working circuit of an APS group can be configured on one 7705 SAR node while the protection circuit of the same APS group is configured on a different 7705 SAR node. The working and protection nodes are connected by an IP link that establishes an MC-APS signaling path between the nodes.

The working and protection circuit must have compatible configurations, such as the same speed, framing, and port type. The circuits in APS group in both the working and protection nodes must also have the same group ID, but they can have different port descriptions. In order for MC-APS to function correctly, pseudowire redundancy must be configured on both the working and protection circuits. For more information, refer to 7705 SAR Services Guide. MC-APS with pseudowire redundancy also supports Inter-Chassis Backup (ICB); see MC-APS and Inter-Chassis Backup for more information.

The working and protection nodes can be different platforms, such as a 7705 SAR-8 and a 7705 SAR-18. However, to prevent possible switchover performance issues, it is recommended to avoid mixing different platform types in the same MC-APS group. The 7705 SAR does not enforce configuration consistency between the working circuit and the protection circuit. Additionally, no service or network-specific configuration data is signaled or synchronized between the two routers.

An MC-APS signaling path is established using the IP link between the two routers by matching APS group IDs. A heartbeat protocol can also be used to add robustness. The signaling path verifies that one router is configured as the working circuit and the other is configured as the protection circuit. In case of a mismatch, an incompatible neighbor trap is generated. The protection router uses K1/K2 byte data, member circuit status, and APS Tools Commands to select the working circuit. Changes in working circuit status are sent across the MC-APS signaling link from the working router to keep the protection router synchronized. External requests such as lockout, force, and manual switches are allowed only on the APS group with the protection circuit.

Figure 13 shows an MC-APS group with physical port, adapter card, and node protection. Figure 14 shows a packet network using MC-APS.

Figure 13:  MC-APS with Physical Port, Adapter Card and Node Protection 

Figure 14:  MC-APS Application 

3.2.15.3.1. MC-APS and Inter-Chassis Backup

ICB (Inter-Chassis Backup) spoke SDPs are supported for use with Cpipe services in an MC-APS configuration. ICB improves switch times, provides additional protection in case of network failures, and reduces packet loss when an active endpoint is switched from a failed MC-APS node to the protection node. Figure 15 shows an MC-APS group with pseudowire redundancy and ICB protection.

Figure 15:  MC-APS with Pseudowire Redundancy and ICB 

If the active link on the access side fails, MC-APS switchover triggers and subsequently triggers pseudowire redundancy switchover. A failure on the network side triggers pseudowire redundancy switchover but not MC-APS switchover. For detailed information on pseudowire redundancy with ICB protection, refer to 7705 SAR Services Guide, “VLL Services”.

3.2.15.4. K1 and K2 Bytes

The APS protocol uses the K1 and K2 bytes of the SONET/SDH header to exchange commands and replies between the near end and far end.

The switch priority of a request is assigned by bits 1 through 4 of the K1 byte, as shown in Table 16.

In unidirectional mode, the K1 and K2 bytes are not used to coordinate switch action; however, the K1 byte is still used to inform the other end of the local action, and bit 5 of the K2 byte is set to 0 to indicate 1+1 APS mode (see Table 17).

In bidirectional mode, the highest-priority local request is compared to the remote request (received from the far-end node using an APS command), and whichever request has the greater priority is selected. The requests can be automatically initiated (such as Signal Failure or Signal Degrade), external (such as Lockout, Forced Switch, Request Switch), or state requests (such as Revert-Time timers).

The channels requesting the switch action are assigned by bits 5 through 8. Only channel number codes 0 and 1 are supported on the 7705 SAR. If channel 0 is selected, the condition bits show the received protection channel status. If channel 1 is selected, the condition bits shows the received working channel status.

The K2 byte is used to indicate bridging actions performed at the line termination equipment (LTE), the provisioned architecture, and mode of operation, as shown in Table 17.

3.2.15.5. Revertive Mode

1+1 APS provides revertive and non-revertive modes; non-revertive mode is the default option. In revertive mode, the activity is switched back to the working port after the working line has recovered from a failure (or the manual switch is cleared). In non-revertive mode, a switch to the protection line is maintained even after the working line has recovered from a failure (or the manual switch is cleared).

To prevent frequent automatic switches that result from intermittent failures, a revert-time is defined for revertive switching. The revert-time is configurable from 0 to 60 min in increments of 1 min; the default value is 5 min. In some scenarios, performance issues can occur if the revert-time is set to 0; therefore, it is recommended that the revert-time always be set to a value of 1 or higher. Any change in the revert-time value takes effect upon the next initiation of the wait-to-restore (WTR) timer. The change does not modify the length of a WTR timer that has already been started. The WTR timer of a non-revertive switch can be assumed to be infinite.

If both working and protection lines fail, the line that has less-severe errors will be active. If there is signal degradation on both ports, the active port that failed last will stay active. If there is signal failure on both ports, the working port will always be active because signal failure on the protection line is a higher priority than on the working line.

3.2.15.6. APS Tools Commands

3.2.15.7. APS Failure Codes

3.2.17.1. Microwave Link Overview

A microwave link allows a 7705 SAR-8 or 7705 SAR-18 to be connected to a 9500 MPR-e radio node. The MPR-e is the zero-footprint (outdoor) microwave solution offered by Nokia that allows customers to migrate from TDM microwave to pure packet microwave. The following MPR-e radio variants are supported:

A microwave link is configured on a 7705 SAR-8 or 7705 SAR-18 as a virtual port object (not as a physical port) using the CLI command mw-link-id (for more information on how to configure a microwave link, see Microwave Link Commands).

Note: Before a microwave link can be configured, the current 7705 SAR software package that includes the MPR-e radio software must be downloaded from OLCS to the 7705 SAR-8 or 7705 SAR-18. See MPR-e Radio Software and Upgrade Management for more information.

The supported microwave link types are 1+0 and 1+1 Hot Standby (HSB). To deploy an N+0 link (with N ≥ 2), multiple links of 1+0 can be configured separately.

A microwave link connection is made from ports 1 through 4 on a Packet Microwave Adapter card to an MPR-e radio using one of the methods described in the 7705 SAR Packet Microwave Adapter Card Installation Guide, “Delivering Data to an MPR-e Radio”. The radio can be configured in standalone mode to provide a basic microwave connection as described in Standalone Mode or in Single Network Element (Single NE) mode to provide the advanced networking capabilities described in Single NE Mode. The default configuration is Single NE mode.

When connected to an MPR-e radio, these ports, with microwave link configured, operate as Gigabit Ethernet ports and provide the same features as the other ports (ports 5 through 8), except for the following:

If a microwave link is not configured on ports 1 through 4, they provide all of the same features as the other Gigabit Ethernet ports (ports 5 through 8).

3.2.17.2. Standalone Mode

A microwave link from ports 1 through 4 on a Packet Microwave Adapter card to an MPR-e radio that is configured in standalone mode provides a basic microwave connection to the MPR-e radio. In standalone mode, each MPR-e radio that is connected to a 7705 SAR-8 or 7705 SAR-18 is managed as a separate standalone NE by the MPT Craft Terminal (MCT) Element Manager.

3.2.17.3. Single NE Mode

A microwave link from ports 1 through 4 on a Packet Microwave Adapter card to an MPR-e radio that is configured in Single NE mode provides the following networking capabilities to the radio over the microwave link:

3.2.17.3.1. Single NE Management

MWA allows the 7705 SAR-8 or 7705 SAR-18 and the MPR-e radios to which it is connected to be integrated and managed as a Single NE. The following features are part of Single NE management:

1. One Management IP Address
2. MPR-e Radio Configuration Management
3. MPR-e Radio Alarm Management
4. MPR-e Radio Software and Upgrade Management
5. MPR-e Radio Configuration Database File Management
6. MPR-e Radio Inventory and Microwave Link Performance Statistics
7. MPR-e Radio Reset Control
8. MPR-e Radio Mute Control

3.2.17.3.1.1. One Management IP Address

The individual management and IP address of the MPR-e radios are no longer required for network management. When managing a microwave network (consisting of a 7705 SAR-8 or 7705 SAR-18 that is connected to one or more MPR-e radios) using an element/network manager, only the IP address of the 7705 SAR-8 or 7705 SAR-18 needs to be entered. This capability optimizes the microwave network’s IP addressing plan.

3.2.17.3.1.2. MPR-e Radio Configuration Management

For an MPR-e configuration, the required MWA-specific parameters are configured on the 7705 SAR side using the CLI and the required non-MWA parameters are configured on the MPR-e side using the MCT.

The following MWA-specific parameters are configured on the 7705 SAR side:

1. 1+1 HSB parameters
2. Epipe VLAN SAP parameters (in a mixed microwave link scenario, where there is interworking between a 7705 SAR MPR-e system and an MSS 9500 MPR system using a TDM2Ethernet service, specific MPR-e system parameters are configured under the Epipe VLAN SAP; for more information, refer to the 7705 SAR Services Guide, “Configuring Epipe SAP Microwave Link Parameters for Interworking with TDM2 Ethernet”).

The following parameters are configured on the MPR-e side:

1. radio link parameters
2. QoS classification parameters

Configuration done on the MPR-e side is collected in a configuration file; this file can be saved to a 7705 SAR-8 or 7705 SAR-18 using the Commit button function on the MCT or an admin>save CLI command on the 7705 SAR-8 or 7705 SAR-18.

3.2.17.3.1.3. MPR-e Radio Alarm Management

An MPR-e radio generates alarms for fault conditions pertaining to the MPR-e hardware and to the microwave link over which it is connected. The alarms are sent to the 7705 SAR-8 or 7705 SAR-18, which turns the alarm notifications into SNMP traps and log events. These log events are controlled in the same way as all other events on the 7705 SAR-8 and 7705 SAR-18 and can be displayed using the show>log>event-control>mwmgr command. Refer to the 7705 SAR System Management Guide, “Event and Accounting Logs”, for more information.

3.2.17.3.1.4. MPR-e Radio Software and Upgrade Management

The Single NE capability optimizes the MPR-e radio software installation and upgrade process. The MPR-e radio software is bundled with the 7705 SAR software as one package, there is no need to look for and download the MPR-e radio software separately. The 7705 SAR software package containing the MPR-e radio software can be downloaded from a directory on OLCS. The operator can copy the software package onto a compact flash or network store on the 7705 SAR-8 or 7705 SAR-18.

Note: There are two TiMOS .zip files on OLCS that contain the current 7705 SAR software package; the file that contains the MPR-e radio software has the .MWA annotation in the filename. Only the MPR-e radio software that is bundled with this 7705 SAR software package is recognized as being valid by the 7705 SAR-8 or 7705 SAR-18.

3.2.17.3.1.5. MPR-e Radio Configuration Database File Management

An MPR-e radio’s database file is stored and backed up on a 7705 SAR-8 or 7705 SAR-18. If an old MPR-e radio is replaced by a new one, the new MPR-e radio downloads the MPR-e radio software from the 7705 SAR-8 or 7705 SAR-18, along with the backed-up database file of the old MPR-e radio. This means that the MPR-e radio does not need to be reconfigured after a radio hardware replacement.

A separate database file is required for each managed MPR-e radio. The user specifies the filename of the database file to be used during provisioning of the radio on the 7705 SAR-8 or 7705 SAR-18 using the config>port>mw>radio>database CLI command.

3.2.17.3.1.6. MPR-e Radio Inventory and Microwave Link Performance Statistics

The following MPR-e radio system information and microwave link information and statistics can be accessed through a CLI session on the 7705 SAR-8 or 7705 SAR-18:

1. MPR-e radio system information
   1. equipment type
   2. inventory information
   3. radio frequency band
   4. temperature
   5. radio transmit status

1. microwave link statistics
   1. MPR-e radio Ethernet statistics
   2. local Tx power
   3. local Rx power
   4. remote Tx power
   5. remote Rx power

      Note: Local/remote Rx power monitoring and local/remote Tx power monitoring are also known as Receive Signal Level (RSL) monitoring and Transmit Signal Level (TSL) monitoring, respectively.

3.2.17.3.1.7. MPR-e Radio Reset Control

MPR-e radio reset control is provided on the 7705 SAR-8 or 7705 SAR-18. During an MPR-e radio reset, the microwave link is brought down and an upper layer applications action is triggered, such as message rerouting and clock source switching by the System Synchronization Unit (SSU).

3.2.17.3.1.8. MPR-e Radio Mute Control

MPR-e radio mute control can be enabled through the CLI/SNMP or by using the MCT. The MCT and CLI are synchronized to show the current state of the MPR-e radio mute function.

Note: Administratively disabling the microwave link with which the MPR-e radio is associated (using the config>port>mw-link-id>shutdown command) causes the main and spare MPR-e radios to be muted.

3.2.17.3.2. Microwave Link Fast Fault Detection (FFD)

The microwave link Fast Fault Detection (FFD) capability allows a 7705 SAR-8 or 7705 SAR-18 to directly detect MPR-e radio or microwave link faults using proprietary messaging. The following fault types are detected by FFD:

1. a radio signal failure
2. an MPR-e radio hardware failure
3. an incompatible MPR-e radio setting
4. a High Bit Error Rate (HBER) condition
5. a Remote Defect Indication (RDI) condition

Note: FFD does not cause the SSU to disqualify the microwave link as a clock source if a fault condition is detected; SSM must be enabled in order to provide this function. The microwave link hold time (hold-up time and hold-down time) must be configured in order to suppress link flapping. The hold-up and hold-down times delay advertising the transition of the microwave link status to the upper layer applications, including IP/MPLS and SSU. The hold-time range is between 0 and 900 s.

If microwave link faults are detected, an event is logged and the link is disabled. Some detected faults may be selectively suppressed using the suppress-faults command. When faults are suppressed, the event is still logged, but the microwave link is not disabled. Operators can suppress HBER faults, RSL threshold crossing faults, and/or RDI faults. By default, the system does not suppress faults for FFD.

3.2.17.3.3. 1+1 HSB

MWA uses 1+1 HSB to protect against microwave link, MPR-e radio, and Packet Microwave Adapter card failures, as well as frequency channel selective fading. Additionally, hitless (errorless) switching provides zero packet loss if a switchover occurs from a main to a spare MPR-e radio.

The following are required for 1+1 HSB:

1. one frequency channel
2. two MWA Gigabit Ethernet ports (configured in network mode) on two different Packet Microwave Adapter cards installed in adjacent slots (for example, slot 1/2 or slot 5/6); port 1 on one card protects port 1 on the adjacent card, port 2 protects port 2 on the adjacent card, and so on.
3. two MPR-e radios (one main and one spare), each connected to one of the MWA Gigabit Ethernet ports on a Packet Microwave Adapter card

   Note: An MPR-e radio that is connected to an odd-numbered port on the Packet Microwave Adapter card must be configured as the main radio.

The following protection schemes make up 1+1 HSB:

1. 1+1 Equipment Protection Switching (EPS)
2. 1+1 Transmission Protection Switching (TPS)
3. 1+1 Radio Protection Switching (RPS)
4. 1+1 HSB Transmit Diversity Antenna (TDA)

These protection schemes are enabled using the config>port>mw>protection command, with the exception of Transmit Diversity Antenna, which is enabled via the MCT. They interwork with each other as described in the sections that follow.

3.2.17.3.3.1. 1+1 Equipment Protection Switching (EPS)

EPS protects against MPR-e radio, MWA Gigabit Ethernet link, and Packet Microwave Adapter card failures. After the radio frames are processed by the active EPS MPR-e radio, the radio sends the Ethernet traffic down to the 7705 SAR-8 or 7705 SAR-18. The standby EPS MPR-e radio does not send any Ethernet traffic down to the 7705 SAR-8 or 7705 SAR-18.

The switching criteria for EPS are:

1. an MPR-e radio hardware failure
2. an MWA Gigabit Ethernet link failure between the 7705 SAR-8 or 7705 SAR-18 and an MPR-e radio
3. a Packet Microwave Adapter card connected to an active EPS MPR-e going into a missing or failure state

3.2.17.3.3.2. 1+1 Transmission Protection Switching (TPS)

In a 1+1 HSB configuration, TPS protects against a microwave link transmission failure by ensuring that only one MPR-e radio at a time uses the antenna for signaling. The 7705 SAR-8 or 7705 SAR-18 sends traffic to both the active and standby TPS MPR-e radios. Upon receiving the baseband traffic, both radios modulate it and up-convert it to signals. However, only the active TPS MPR-e radio transmits the RF signals; the standby TPS MPR-e radio suppresses the signals. When the active TPS MPR-e radio fails, standby radio becomes active and restores the microwave link channel.

The switching criteria for TPS are identical to EPS.

Note: The state of the EPS and TPS MPR-e radios are linked to each other. If an alarm occurs, an automatic switchover for EPS and TPS is activated simultaneously. However, if a manual switchover is configured, the switchover is decoupled and the state of the EPS and TPS MPR-e radios is no longer identical. A manual switchover can be configured for EPS but not for TPS.

3.2.17.3.3.3. 1+1 Radio Protection Switching (RPS)

RPS is a hitless radio function that provides space diversity protection for the microwave channel. On the receive side, each MPR-e radio monitors the same radio frequency channel, with the main MPR-e radio being the active receiver by default. Both active and standby RPS MPR-e radios receive both streams of radio frames. The standby RPS MPR-e radio sends the stream of radio frames that it receives to the active EPS MPR-e radio.

Note: In order to provide space diversity (SD) for the two radio frequency channels, RPS requires that a separate antenna be mounted for each MPR-e radio.

Figure 16 shows a typical application of 1+1 HSB with SD deployment. Only one microwave frequency channel is active and only the main MPR-e radio is transmitting data to the remote ends; the spare MPR-e radio is acting as a standby.

Figure 16:  1+1 HSB with SD Deployment 

3.2.17.3.3.4. 1+1 HSB Transmit Diversity Antenna (TDA)

The TDA feature provides another layer of protection over a microwave link. The TDA configuration uses a main antenna mounted on one MPT-HLC radio and a diversity antenna mounted on another MPT-HLC radio. In combination with the 1+1 HSB radio configuration (redundant MPR-e radios), the traffic is transmitted on either the main antenna or the diversity antenna to achieve the Space Diversity (SD) receiver configuration.

TDA provides protection switching independent of TPS. TDA is capable of counter-acting either negative propagation conditions or permanent antenna failure.

The main antenna is the default main unit that controls the antenna traffic flow using the TDA algorithm. If the main unit fails, the TDA algorithm is no longer operational on the main unit; its transmission switches over to the diversity antenna.

The non-operation of the main antenna switch does not affect transmission, even while the TDA algorithm is being transmitted on the diversity antenna.

TDA configuration is done via the MCT. TDA status is available using the 7705 SAR CLI/SNMP and via the MCT. The CLI command that is used is show>mw>link. The status information includes the current TDA configuration, which antenna is active, and the active antenna position.

Figure 17 shows an example of a TDA application.

Figure 17:  Example of a TDA Application 

3.2.17.3.3.5. Communication Method Between the Main and Spare MPR-e Radio

In a 1+1 HSB configuration, the communication path between the main (active) and spare (standby) MPR-e radios installed on a tower is set up using a tight cable.

Note: A tight cable is required with MPT-HC V2, MPT-XP, MPT-HLC, and MPT-QAM radios (1+ 1 HSB is not supported on MPT-MC radios).

3.2.17.3.4. 1+1 Switching Operation

The following list defines the types of EPS, TPS, and RPS MPR-e radio switching operations that can be enabled using the tools>perform>mw>link command. Refer to the 7705 SAR OAM and Diagnostics Guide, “Tools Command Reference”, “Tools Perform Commands”, for more information.

Note: TDA switching operation is enabled via the MCT.

1. lockout—prevents the spare MPR-e radio from ever becoming the main radio, even when the main MPR-e radio fails; this operation overrides any forced, automatic, or manual operation
2. forced —forces the spare MPR-e radio to become the main MPR-e radio, even though it might not be in a fit state to assume the role. A forced switch operation overrides any automatic or manual switch operation that is in place.
3. automatic—allows an MPR-e radio to perform an automatic switchover if a fault condition exists. An automatic switch operation overrides any manual switch operation that is in place.
4. manual—attempts to switch the main/spare status of an MPR-e radio; however, if port failures, equipment failures, and reception failures do not allow the switchover, an automatic switch operation is triggered.

You can also configure revertive switching for RPS and EPS/TPS (when revertive switching is configured for EPS, it is also applied to TPS; revertive switching for TPS cannot be configured separately). Revertive switching occurs when the MPR-e radio operation switches from the spare radio back to the main radio after a fault condition is cleared.

3.2.17.4. Frequency Synchronization

Depending on the type of Gigabit Ethernet microwave link used to connect the Packet Microwave Adapter card and an MPR-e radio, different frequency synchronization mechanisms can be used.

When using optical 1000Base-SX to connect the Packet Microwave Adapter card and an MPR-e radio, synchronous Ethernet and SSM are the frequency synchronization mechanisms that are used. SSM is used as the mechanism to detect a microwave link failure, including loss of frame and MPR-e radio hardware failure.

When using electrical 1000Base-T to connect the Packet Microwave Adapter card and an MPR-e radio, PCR is the frequency synchronization mechanism that is used (a copper SFP is mandatory on ports 3 and 4).

For more information on PCR, synchronous Ethernet, and SSM, refer to the 7705 SAR Basic System Configuration Guide, “Node Timing”.

3.2.17.5. RSL History

An MPR-e radio that is connected to the 7705 SAR can automatically upload its received signal level (RSL) history file to the 7705 SAR host. The RSL file contains a history of radio attributes and alarms that radio operators can use to isolate and diagnose radio-layer problems that might exist in the network.

Up to 24 MPR-e radios can independently upload their RSL history file every 15 minutes when the rsl-history command is configured on the 7705 SAR for each radio. When uploaded, the file is stored on the 7705 SAR compact flash. Each RSL file can be up to 1 Mbyte and contain up to 10 000 lines. Each time a new file from a specific MPR-e radio is sent to the 7705 SAR, the new file overwrites the previous version for that radio. Once uploaded to the 7705 SAR, the operator can view the file in its raw format using the file>type command or FTP it to an external server.

Table 19 lists the attributes in the RSL history file.

3.2.18.1. DSL Bonding Overview

The 7705 SAR-M (variants with module slots) supports two DSL modules designed to transport high-volume, best-effort HSDPA traffic or to be used as a pure DSL backhaul option. The 6-port DSL Combination module supports four G.SHDSL.bis pairs and two ADSL2, ADSL2+, or VDSL2 pairs. The 8-port xDSL module supports eight pairs of ADSL2, ADSL2+, or VDSL2.

The 7705 SAR-Wx variants that support Ethernet and xDSL each provide 4-pair xDSL PTM bonding (ADSL2+ or VDSL2) on the RJ-45 xDSL port. Refer to the 7705 SAR-Wx Chassis Installation Guide for more information on the xDSL port on the 7705 SAR-Wx.

DSL bonding allows multiple physical DSL links to be combined in one logical link to increase bit rate capacity to the subscriber and/or extend the reach of existing services. DSL bonding is activated by the handshake messages between the Central Office and CPE as defined in ITU-T G.994.1. Once the port is configured for bonded mode, any pairs not included in the bonded groups cannot be used to carry traffic.

The 6-port DSL Combination module supports up to two bonding groups, one for SHDSL and one for xDSL. The 8-port xDSL module and the RJ-45 xDSL port on the 7705 SAR-Wx support only one bonding group. The DSLAM handshake determines the number of DSL pairs used in each bonding group as shown in Table 20.

Bonding functions are driven entirely by the Central Office with the exception of the ATM VPI/VCI when ATM bonding is used on an xDSL interface.

The 7705 SAR-M supports both ATM and PTM bonding. The 7705 SAR-Wx supports PTM bonding.

3.2.18.2. ATM Bonding

ATM bonding is specified by ITU-T G.998.1 and is used for ATM-based transmission links for all types of ADSL. ATM bonding adds sequence information to ATM cells, allowing resequencing by adding delay variation to account for speed differences across multiple physical links in one bonding group. ATM bonding is sometimes referred to as multi-ADSL bonding because multiple ADSL lines typically use ATM-based transmission links.

ATM bonding acts as an alternative to IMA as a method of logically combining multiple lines transmitting ATM cells. ATM bonding differs from IMA in the following ways:

The 8-port xDSL module and the xDSL interface of the 6-port DSL Combination module support 2-pair ATM bonding for ADSL2 and ADSL2+. When operating in ATM bonded mode, the remaining 6 pairs on the 8-port xDSL module cannot be used. Additionally, the only protocol stack supported is Ethernet over ATM with RFC 2684 LLC/SNAP bridged ATM packets. In ATM bonded mode, cell scrambling is always enabled and ATM CLP is disregarded (it is not set or inspected for priority loss indications). Any packet priority marking must be done at the Ethernet, MPLS, or IP layers.

In ATM channel-bonding schemes, the end-user packets are split into 53-byte cells. Each cell is tagged with a sequence ID by replacing bits in the ATM header with sequence ID (SID) bits between bonding entities. The ATM bonding implementation on the 7705 SAR-M currently only supports a 12-bit SID, although G.998.1 specifies support for either an 8-bit or 12-bit SID bound by the aggregate rate, differential delay, and number of links.

For ATM bonding, all bridged PDUs are sent without an FCS field. However, if an attached DSLAM does send bridged PDUs with an FCS field attached, the FCS is honored and is not removed or regenerated.

3.2.18.3. PTM Bonding

PTM bonding is specified by ITU-T G.998.2 and is supported on VDSL2, ADSL2, and ADSL2+ interfaces on the 6-port DSL Combination module and 8-port xDSL module, and on SHDSL on the 6-port DSL Combination module. The 7705 SAR-Wx variants that support Ethernet and xDSL provide 4-pair xDSL PTM bonding (ADSL2+ or VDSL2) on the RJ-45 xDSL port.

PTM bonding and EFM bonding are sometimes used interchangeably, with EFM bonding generally used in conjunction with SHDSL. The SHDSL interface on a 6-port DSL Combination module complies with both PTM specified in ITU-T G.998.2, and EFM specified in IEEE 802.3ah-2004.

PTM bonding applies to DSL links with or without identical transmission speeds. Since PTM implies the use of variable-size PDUs, it makes the use of IMA techniques impossible. PTM bonding combines EFM-based transmission links with limited, or reach-dependent, bandwidth, specifically VDSL2, SHDSL, or ADSL2+ on the 7705 SAR-M and ADSL2+ or VDSL2 on the 7705 SAR-Wx. PTM bonding adds sequence information to transmitted frames or frame fragments, allowing resequencing by adding delay variation to account for speed and PDU size differences across multiple physical links in one bonding group.

In PTM channel-bonding schemes, the end-user packets are split into small fragments of up to 512 bytes. The PTM bonding implementation on xDSL ports uses a fixed fragment size of 204 bytes, which is not user-configurable. The PTM fragment size on the SHDSL ports is set to 256 bytes. When PTM bonding is active on a DSL bundle, fragments are distributed over individual DSL lines. At the receiving end, the fragments are realigned to recover from differential delays in the transmission path, then reassembled into packets.

In order to realign correctly, each fragment is prefixed with a header containing a sequence identifier (SID), a start of packet (SOP) indicator, and an end of packet (EOP) indicator. The receiver side uses the SID to rearrange the incoming cells in the correct order, while the SOP and EOP indications are used to reassemble the stream of cells into complete data packets. If transmitted Ethernet packets are smaller than the PTM fragment size, they are transmitted inside a single fragment.

3.2.18.4. Pairs Within a Bonded Group

Pairs within a bonded group must start with pair 1 and are then sequentially added into each module or port. For example, if a 4-pair bonded group is desired on an interface capable of supporting 4 or more pairs, pairs 1 through 4 should be connected to the DSLAM and configured by the DSLAM into the bonded group. For pinout diagrams, refer to the 7705 SAR DSL Module Installation Guide for RJ-11 pinouts and the 7705 SAR-Wx Chassis Installation Guide for RJ-45 pinouts.

On the ISAM, bonding makes use of either chipset or LT-level (Line Termination card-level) bonding. For LT-level bonding, the interworking function on the LT board allows non-contiguous ports on the same LT to be bonded. LT-level bonding is used to configure 8-pair bonding on the ISAM, which is also handled by dedicated hardware that incorporates both bonding and xDSL interworking functions. SHDSL bonding functions are provided on the ISAM via chipset level bonding.

Within a bonding group, the line used to identify the whole group is referred to as the primary link. The other lines in the bonding group are referred to as secondary or slave links. The supported bit rate over the bonding group is the sum of the actual net bit rates on all lines in the group.

3.2.18.5. Configuration

All DSL ports are considered the functional equivalent of an Ethernet port and support many of the same features and configuration commands. Data from the router’s central network processor transmit and receive Ethernet packets to and from the 7705 SAR-M module slot or 7705 SAR-Wx port.

If xDSL lines train in ATM bonding mode over ADSL2/2+, the VPI/VCI configured on that port is used by the module or platform to interwork Ethernet packets into AAL5 LLC snap-bridged PDUs without user intervention.

All lines for both the 6-port DSL Combination module and the 8-port xDSL module are configured from the ISAM via the G.994.1 (G.hs) handshake. All lines operate in auto-detect mode; therefore, there are no individual line configurations required with the exception of the configuration of VPI/VCI for ATM bonding and the configuration of ADSL2/2+ Annex B support if ISDN support is required, on an xDSL interface.

DSL modules and ports automatically detect any existing configuration and will attempt to bring pairs into service. For PTM bonding, the underlying transport mechanism is Ethernet. For ADSL2+ ATM bonding, the underlying transport mechanism is ATM, which requires a configured VPI/VCI. The default VPI/VCI on the 7705 SAR-M is 8/35, and only a single VC can be configured.

The only mode of operation for all SHDSL and xDSL pairs on the 7705 SAR-M is bonded mode. On the 7705 SAR-Wx, the only mode for xDSL pairs is PTM bonded mode.

Log files are created to record critical events during xDSL and SHDSL chipset initialization and for any DSL-related operational events. The log file can be viewed through the CLI or the NSP NFM-P for debugging and troubleshooting. The event data can be directed to the default log file or to a specific user-configured log file.

The CLI commands to configure DSL are found under the config>port>dsl context.

3.2.18.6. Layer 3 Protocol Support and Service Provisioning

Table 21 lists the limits for the 6-port DSL Combination module, the 8-port xDSL module, and the RJ-45 xDSL port on the 7705 SAR-Wx.

3.6.5.1. VCB Applications

VCB can be configured in one of four applications. These applications are set at the card level. Each application uses a bridging algorithm that determines which branches control the management of the bridge and transmission of signals:

3.6.5.2. Gain

Gain is the increase or decrease in signal power or voltage that occurs in transmitting a signal from one point to another. The two types of gain are:

Gain is configured at the branch level.

The input gain defines the magnitude of the increase or decrease of the signal transmitted into the bridge. The input gain range is –16 to +9 dB in 1-dB increments (the default is 0 dB).

The output gain defines the magnitude of the increase or decrease of the signal received from the bridge. The output gain range is –16 to +9 dB in 1-dB increments (the default is 0 dB).

3.6.6.1. Raw Socket Configuration

A raw socket IP transport interface can be configured for each RS-232 serial port on a node. This allows the serial port to receive TCP connections or UDP session packets from multiple remote hosts, or to create new sessions to remote hosts in order to send and receive serial data to and from those remote hosts.

There are port-level and service-level configuration requirements for a raw socket serial port to send and receive serial data in either server mode, client mode, or both.

Raw socket port-level configuration includes defining the end-of-packet checking parameters (idle-time, length, special character) and the inter-session delay for transmitting session data over the serial link. See Serial Commands for the required information.

At the service level, an IP transport subservice is created within an IES or VPRN service to associate the serial port with the respective IES or VPRN service. TCP/UDP encapsulated serial data is routed within the corresponding Layer 3 IES or VPRN service. The required configuration includes IP transport subservice local-host and remote-host configuration, TCP timers, and session control. Refer to the 7705 SAR Services Guide, “IES Raw Socket IP Transport Configuration Commands” and “VPRN Raw Socket IP Transport Configuration Commands” for the required information.

3.6.6.2. Raw Socket Packet Processing

Figure 27 illustrates how raw socket packets are processed over a serial link.

Session data attempting to access the serial port is queued. One queue is maintained per session. The purpose of the session queue is to prevent two different flows of packets from interleaving out the serial port and creating unreadable messages. When data is being transmitted over the serial link for a session, any other session’s data is queued until the first session has emptied its queue. The next session’s data is transmitted over the serial link only after the inter-session-delay timer expires. Each session’s data is sent out in round-robin fashion.

Figure 27:  Raw Socket Packet Processing 

3.6.6.3. Raw Socket Squelch Functionality

A condition may occur where the end device connected to the serial port continues to send out a continuous stream of data after the normal response period has expired. This can prevent the far-end remote host or master equipment from receiving data from other end devices in the network. To resolve this condition, the squelch command can be used on the raw socket at the port level (it is disabled by default). This stops the socket from receiving any more data from the problematic device.

If the command is enabled, the 7705 SAR will monitor the serial port for a constant character stream. A configurable squelch delay period, using the squelch-delay command, is used to determine how long to measure the constant character stream before initiating the squelch function. If the squelch function is initiated, the port is considered locked up and an alarm is raised indicating the lock-up and that the squelching function has been triggered.

The serial port can be forced out of squelch and put back to normal, either manually using the squelch-reset command or automatically using the unsquelch-delay command. The unsquelch-delay command defines the time to wait after squelch is initiated before it is removed.