Uniform RADIUS Server Configuration (Preferred)

This configuration method is preferred as it can be re-used amongst multiple applications (Subscriber authentication and accounting, L2TP tunnel accounting, WLAN gateway RADIUS proxy,) and enables additional functionality not available in the legacy configuration method. For example:

Note: A RADIUS server is marked down if it detects a number of consecutive timeouts independent of transaction-id or origin of request.

Where a number of consecutive timeouts is defined by the number of retries configured below the radius-server-policy servers.

The default number of retries is 3, meaning 1 initial try and 2 retries.

If, for example, the RADIUS server has “2 timeouts, 1 reply, 1 timeouts”, whereby the timeouts are originated for the same host, the server is not marked down since intermediate replies were received.

To attach a RADIUS server policy to an authentication policy:

For example,

Note: To avoid conflicts, the following CLI commands are ignored in the authentication policy when a radius-server-policy is attached: All commands in the radius-authentication-server context accept-authorization-change coa-script-policy accept-script-policy request-script-policy The fallback-action command specifies the action when no RADIUS server is available is configured direct in the config>subscr-mgmt>auth-plcy CLI context.

To attach a RADIUS server policy to a RADIUS accounting policy:

For example:

Note: To avoid conflicts, the following CLI commands are ignored in the RADIUS accounting policy when a radius-server-policy is attached: All commands in the radius-accounting-server context acct-request-script-policy

To configure the RADIUS servers in a RADIUS server policy:

For example:

To configure the RADIUS servers in the routing instance:

For example:

Note: To configure RADIUS CoA servers for use in Enhanced Subscriber Management, the server must be configured in the corresponding routing instance with the accept-coa command enabled.

Legacy RADIUS Server Configuration

Note: It is recommended to migrate to the uniform RADIUS server configuration as described above to have additional functionality enabled.

To configure a RADIUS server in an authentication policy:

Note: In legacy RADIUS server configuration, to configure RADIUS CoA servers for use in Enhanced Subscriber Management, the server must be configured in the authentication policy with the accept-authorization-change command enabled. A CoA only server can be configured with the optional coa-only flag.

To configure a RADIUS server in a RADIUS accounting policy:

Triple Play Network with RADIUS Authentication

Figure 61:  Triple Play Aggregation Network with RADIUS-Based DHCP Host Authentication 

Figure 61 shows a flow of RADIUS authentication of DHCP hosts in the triple play aggregation environment. Besides granting the authentication of given DHCP host, the RADIUS server can include RADIUS attributes (standard and/or Vendor-Specific Attributes (VSAs)) which are then used by the network element to provision objects related to a given DHCP host.

RADIUS is a distributed client/server concept that is used to protect networks against unauthorized access. In the context of the router’s subscriber management in TPSDA, the RADIUS client running on nodes sends authentication requests to the SSC.

RADIUS can be used to perform three distinct services:

The RADIUS protocol uses “attributes” to describe specific authentication, authorization and accounting elements in a user profile (which are stored on the RADIUS server). RADIUS messages contain RADIUS attributes to communicate information between network elements running a RADIUS client and a RADIUS server.

RADIUS divides attributes into two groups, standard attributes and Vendor-Specific Attributes (VSAs). VSA is a concept allowing conveying vendor specific configuration information in a RADIUS messages, discussed in RFC 2865, Remote Authentication Dial In User Service (RADIUS). It is up to the vendor to specify the exact format of the VSAs. Alcatel-Lucent-specific VSAs are identified by vendor-id 6527.

Calling-Station-ID

A calling-station-id can be configured at SAP level and can be included in the RADIUS authentication and accounting messages. This attribute is used in legacy BRAS to identify the user (typically phone number used for RAS connection). In the broadband networks this was replaced by circuit-id in Option 82. However, the Option 82 format is highly dependent on access-node vendor, which makes interpretation in management servers (such as RADIUS) troublesome. Some operators use the calling-station-id attribute as an attribute indicating the way the circuit-id should be interpreted. The calling-station-id attribute can be configured as a string which will be configured on the SAP. It can also be configured to use the sap-id, remote-id or mac-address.

Subscriber Session Timeout

To limit the lifetime of a PPP session or DHCPv4 host to a fixed time interval, a timeout can be specified from RADIUS. By default, a PPP session or DHCPv4 host has no session timeout (infinite).

For PPP sessions, a session-timeout can be configured in the ppp-policy. A RADIUS specified session-timeout overrides the CLI configured value.

When the session timeout expires a PPP session is terminated and a DHCPv4 host deleted. For a DHCPv4 host, a DHCP release message is also sent to the server .

The following two attributes can be used in RADIUS Access-Accept and CoA messages to limit the PPP session or DHCPv4 host session time (Table 51):

When specified in a RADIUS Access-Accept message, both attributes specify an absolute value for session timeout. When specified in a RADIUS CoA message, attribute [26-6527-160] Alc-Relative-Session-Timeout specifies a relative session timeout value in addition to the current session time while attribute [27] Session-Timeout specifies an absolute session timeout value. If the current session time is greater than the received Session-Timeout, a CoA NAK is sent with error cause “Invalid Attribute Value (407)”.

Only one of the above attributes to specify a session timeout can be present in a single RADIUS message. An event is raised when both are specified in a single message.

The output of the “show service id <service-id> ppp session detail” CLI command contains following fields related to session timeout for PPP sessions:

The output of the “show service id <service-id> dhcp lease-state detail” CLI command contains following fields related to session timeout for DHCPv4 hosts:

Note: In a radius-proxy scenario or when a DHCPv4 host is created with a RADIUS CoA message, the RADIUS attribute [26-6527-174] Alc-Lease-Time attribute must be used to specify the lease time. If the [26-6527-174] Alc-Lease-Time is not present in these scenarios, then the RADIUS attribute [27] Session-Timeout is interpreted as DHCPv4 lease time.

RADIUS Reply Message for PPPoE PAP/CHAP

The string returned in a [18] Reply-Message attribute in a RADIUS Access-Accept is passed to the PPPoE client in the CHAP Success or PAP Authentication-Ack message.

The string returned in a [18] Reply-Message attribute in a RADIUS Access-Reject is passed to the PPPoE client in the CHAP Failure or PAP Authentication-Nak message.

When no [18] Reply-Message attribute is available, the SROS default messages are used instead: “CHAP authentication success” or ”CHAP authentication failure” for CHAP and “Login ok” or ” Login incorrect” for PAP.

SHCV Policy

SHCV policies are used to control “subscriber host connectivity verification” which verifies the host connectivity to the BNG. There are two types of SHCV: periodic and event triggered. Prior to Release 13.0R4, some event triggered SHCV relied on the reference timer set by the host-connectivity-verify under the group interface while others had hardcoded values. Release 13.0R4 introduced the “SHCV policy” that allows individual configuration of trigger SHCV timers and periodic SHCV timers depending on the application.

Provisioning IP Configuration of the Host

The other aspect of subscriber-host authorization is providing IP configuration (ip-address, subnet-mask, default gateway and dns) through RADIUS directory rather then using centralized DHCP server. In this case, the node receiving following RADIUS attributes will assume role of DHCP server in conversation with the client and provide the IP configuration received from RADIUS server.

These attributes will be accepted only if the system is explicitly configured to perform DHCP-server functionality on a given interface.

The following RADIUS attributes will be accepted from authentication-response messages:

RADIUS Based Authentication in Wholesale Environment

In order to support VRF selection, the following attributes are supported:

Change of Authorization and Disconnect-Request

In a typical RADIUS environment, the network element serves as a RADIUS client, which means the messages are originated by a routers. In some cases, such as “mid-session” changes, it is desirable that the RADIUS server initiates a CoA request to impose a change in policies applicable to the subscriber, as defined by RFC 3576.

To configure a RADIUS server to accept CoA and Disconnect Messages is achieved in one of the following ways:

Note: There is a priority in the functions that can be performed by CoA. The first matching one will be performed: If the CoA packet contains a force-renew attribute, the subscriber gets a force-renew DHCP packet. This function is not supported for PPPoE or ARP hosts. If the CoA packet contains a create-host attribute, a new lease-state is created. Only DHCP lease-states can be created by a CoA message. PPPoE sessions and ARP hosts cannot be created. Otherwise, the ESM strings are updated.

There are several reasons for using RADIUS initiated CoA messages:

If the changes to ESM attributes are required, the RADIUS sever will send CoA messages to the network element requesting the change in attributes included in the CoA request:

As a reaction to such message, the router changes the ESM settings applicable to the given host.

If changes to the IP configuration (including the VRF-id in the case of wholesaling) of the given host are needed, the RADIUS server may send a CoA message containing VSA indicating request for forcerenew generation:

As a reaction to such message, router will generate a DHCP forcerenew message for the given subscriber host. Consequently, during the re-authentication, new configuration parameters can be populated based on attributes included in Authentication-response message. The force-NAK attribute has the same function as the force-renew attribute, but will cause the ESR to reply with a NAK to the next DHCP renew. This will invalidate the lease state on the ESR and force the client to completely recreate its lease, making it possible to update parameters that cannot be updated through normal CoA messages, such as IP address or address pool.

If the configuration of the new subscriber-host is required, RADIUS server will send a CoA message containing VSA request new host generation along with VSAs specifying all required parameters.

After executing the requested action, the router element responds with an ACK or NAK message depending on the success/failure of the operation. In case of failure (and hence NAK response), the element will include the error code in accordance with RFC 3576 definitions if an appropriate error code is available.

Supporting CoA messages has security risks as it essentially requires action to unsolicited messages from the RADIUS server. This can be primarily the case in an environment where RADIUS servers from multiple ISPs share the same aggregation network. To minimize the security risks, the following rules apply:

In all cases (creation, modification, forcerenew) subscriber host identification attributes are mandatory in the CoA request: “NAS-Port-Id + IP” or “Acct-Session-Id” or “Alc-Subsc-ID-Str”

When there are no subscriber host identification attributes present in the CoA, the message will be NAK’d with corresponding error code.

The properties of an existing RADIUS-authenticated PPPoE session can be changed by sending a Change of Authorization (CoA) message from the RADIUS server. Processing of a CoA is done in the same way as for DHCP hosts, with the exception that only the ESM settings can be changed for a PPPoE session (the force-renew attribute is not supported for PPPoE sessions and a Create-Host CoA will always generate a DHCP host.)

For terminating PPPoE sessions from the RADIUS server, the disconnect-request message can be sent from the RADIUS server. This message triggers a shutdown of the PPPoE session. The attributes needed to identify the PPPoE session are the same as for DHCP hosts.

RADIUS-Based Accounting

When a router is configured to perform RADIUS-based accounting, at the creation of a subscriber-host, it will generate an accounting-start packet describing the subscriber-host and send it to the RADIUS accounting server. At the termination of the session, it will generate an accounting-stop packet including accounting statistics for a given host. The router can also be configured to send an interim-accounting message to provide updates for a subscriber-host.

The exact format of accounting messages, their types, and communication between client running on the routers and RADIUS accounting server is described in RFC 2866, RADIUS Accounting. The following describes a few specific configurations.

In order to identify a subscriber-host in accounting messages different RADIUS attributes can be included in the accounting-start, interim-accounting, and accounting-stop messages. The inclusion of the individual attributes is controlled by the following commands.

RADIUS volume accounting attributes are depending on the type of volume reporting and can be controlled via an include-radius-attribute CLI command. Multiple volume reporting types can be enabled simultaneously:

where:

detailed-acct-attributes — Report detailed per queue and per policer counters using RADIUS VSAs (enabled by default). Each VSA contains a queue or policer id followed by the stat-mode or 64 bit counter. The VSA’s included in the Accounting messages is function of the context (policer or queue, stat-mode, MDA type, …):

[26-6527-107] Alc-Acct-I-statmode

[26-6527-127] Alc-Acct-O-statmode

[26-6527-19] Alc-Acct-I-Inprof-Octets-64

[26-6527-20] Alc-Acct-I-Outprof-Octets-64

[26-6527-21] Alc-Acct-O-Inprof-Octets-64

[26-6527-22] Alc-Acct-O-Outprof-Octets-64

[26-6527-23] Alc-Acct-I-Inprof-Pkts-64

[26-6527-24] Alc-Acct-I-Outprof-Pkts-64

[26-6527-25] Alc-Acct-O-Inprof-Pkts-64

[26-6527-26] Alc-Acct-O-Outprof-Pkts-64

[26-6527-39] Alc-Acct-OC-O-Inprof-Octets-64

[26-6527-40] Alc-Acct-OC-O-Outprof-Octets-64

[26-6527-43] Alc-Acct-OC-O-Inprof-Pkts-64

[26-6527-44] Alc-Acct-OC-O-Outprof-Pkts-64

[26-6527-69] Alc-Acct-I-High-Octets-Drop_64

[26-6527-70] Alc-Acct-I-Low-Octets-Drop_64

[26-6527-71] Alc-Acct-I-High-Pack-Drop_64

[26-6527-72] Alc-Acct-I-Low-Pack-Drop_64

[26-6527-73] Alc-Acct-I-High-Octets-Offer_64

[26-6527-74] Alc-Acct-I-Low-Octets-Offer_64

[26-6527-75] Alc-Acct-I-High-Pack-Offer_64

[26-6527-76] Alc-Acct-I-Low-Pack-Offer_64

[26-6527-77] Alc-Acct-I-Unc-Octets-Offer_64

[26-6527-78] Alc-Acct-I-Unc-Pack-Offer_64

[26-6527-81] Alc-Acct-O-Inprof-Pack-Drop_64

[26-6527-82] Alc-Acct-O-Outprof-Pack-Drop_64

[26-6527-83] Alc-Acct-O-Inprof-Octs-Drop_64

[26-6527-84] Alc-Acct-O-Outprof-Octs-Drop_64

[26-6527-91] Alc-Acct-OC-O-Inpr-Pack-Drop_64

[26-6527-92] Alc-Acct-OC-O-Outpr-Pack-Drop_64

[26-6527-93] Alc-Acct-OC-O-Inpr-Octs-Drop_64

[26-6527-94] Alc-Acct-OC-O-Outpr-Octs-Drop_64

[26-6527-108] Alc-Acct-I-Hiprio-Octets_64

[26-6527-109] Alc-Acct-I-Lowprio-Octets_64

[26-6527-110] Alc-Acct-O-Hiprio-Octets_64

[26-6527-111] Alc-Acct-O-Lowprio-Octets_64

[26-6527-112] Alc-Acct-I-Hiprio-Packets_64

[26-6527-113] Alc-Acct-I-Lowprio-Packets_64

[26-6527-114] Alc-Acct-O-Hiprio-Packets_64

[26-6527-115] Alc-Acct-O-Lowprio-Packets_64

[26-6527-116] Alc-Acct-I-All-Octets_64

[26-6527-117] Alc-Acct-O-All-Octets_64

[26-6527-118] Alc-Acct-I-All-Packets_64

[26-6527-119] Alc-Acct-O-All-Packets_64

std-acct-attributes — Report IPv4 and IPv6 aggregated forwarded counters using standard RADIUS attributes (disabled by default):

[42] Acct-Input-Octets

[43] Acct-Output-Octets

[47] Acct-Input-Packets

[48] Acct-Output-Packets

[52] Acct-Input-Gigawords

[53] Acct-Output- Gigawords

v6-aggregate-stats — Report IPv6 aggregated forwarded counters of queues and policers in stat-mode v4-v6 using using RADIUS VSAs (disabled by default):

[26-6527-194] Alc-IPv6-Acct-Input-Packets

[26-6527-195] Alc-IPv6-Acct-Input-Octets

[26-6527-196] Alc-IPv6-Acct-Input-GigaWords

[26-6527-197] Alc-IPv6-Acct-Output-Packets

[26-6527-198] Alc-IPv6-Acct-Output-Octets

[26-6527-199] Alc-IPv6-Acct-Output-Gigawords

In addition to accounting-start, interim-accounting, and accounting-stop messages, a RADIUS client on a routers will send also accounting-on and accounting-off messages. An accounting-on message will be sent when a given RADIUS accounting-policy is applied to a given subscriber-profile, or the first server is defined in the context of an already applied policy. The following attributes will be included in such message:

Accounting-off messages will be sent at following events:

These messages contain following attributes:

In case of dual homing, both nodes will send RADIUS accounting messages for the host, with all attributes as it is locally configured. The RADIUS log files on both boxes need to be parsed to get aggregate accounting data for the given subscriber host regardless the node used for forwarding.

For RADIUS-based accounting, a custom record can be defined to refine the data that is sent to the RADIUS server. Refer to the Configuring an Accounting Custom Record in the OS System Management Guide for further information.

RADIUS Accounting Terminating Cause

The VSA acct-terminate-cause attribute provides some termination information. Two additional attributes: [VSA 227] alc-error-message and [VSA 226] alc-error-code provide additional information in both string and numeric format about the terminating cause of the subscriber session. The full list of error messages and their corresponding error codes can be viewed using the command tools>dump>aaa> radius-acct-terminate-cause.

If required, python can alter the content of both VSAs. The following is a python script example where the error codes are remapped from 123 to 8 and from 124 to 17:

Accounting Modes Of Operation

This section is applicable to the 7750 SR or the 7450 ESS in mixed mode. There are three basic accounting models:

Each of the basic models can optionally be enabled to send interim-updates. Inclusion/exclusion of interim-updates will depend on whether volume based (start/interim-updates/stop) or time based (start/stop) accounting is required.

The difference between the three basic accounting models is in its core related to the processing of the acc-session-id for each model. The differences are related to:

The counters for volume-based accounting are collected from queues or policers that are instantiated per sla-profile instance (SPI) on non-HSMDA based hardware or per subscriber on HSMDA based hardware. This is true irrespective of which model of accounting (or combination of models) is deployed. Within accounting context, the SPI on non-HSMDA or subscriber on HSMDA equates to queue-instance.

Table 52 summarizes the key differences between various accounting modes of operation that are supported. Interim-updates for each individual mode can be enabled/disabled via configuration (interim-updates keyword as an extension to the commands that enable three basic modes of accounting). This is denoted by the IU-Config keyword under the ‘I-U’ column in the table. The table also shows that any two combinations of the three basic models (including their variants for volume/time based accounting) can be enabled simultaneously.

Note: Hosts within the targeted CoA entity will be affected as follows: If the CoA target is the session, then both constituting members (IPv4 and IPv6) of the dual-stack host will be affected. If the CoA target is the queuing-instance, then up to 32 hosts that are sharing that SPI will be affected.

The same principle applies to LI.

The accounting behavior (accounting messages and accounting attributes) in case that the SPI is changed via CoA depends on the accounting mode of operation. On non-HSMDA hardware, the behavior is the following:

On HSMDA, no START/STOPS are sent since queues are not re-instantiated on ingress or egress.

Per Session Accounting

In the per session accounting mode of operation the accounting message stream (START/INTERIM-UPDATE/STOP) is generated per session. The accounting message stream refers to a collection of accounting messages (START/INTERIM-UPDATE/STOP) sharing the same acct-session-id.

In dual-stack PPPoE case, IPv4 and IPv6 hosts are tied to the same (LCP) session. A single authentication request is initiated for such session (triggered by the first host that initiates the session).

For a single stack PPPoE host, the behavior defined in the per session accounting model is indistinguishable from the per host accounting model. The per session accounting model makes difference in behavior only for dual stack PPPoE hosts.

The following are the properties of the Per Session Accounting model:

RADIUS Session Accounting with PD as a Managed Route

The Prefix Delegation (PD) prefix is included in the accounting messages using the VSA [99], Framed-IPv6-Route attribute with the string type “pd-host” appended to differentiate it from a regular framed IPv6 route; for example, FRAMED IPV6 ROUTE [99] 39 2001:1000::/64 :: 0 pref 0 type pd-host. PD as a managed route is applicable to both PPP and IPoE sessions and can point either to an IPv4 host or to an IPv6 WAN host.

Table 53 outlines the RADIUS accounting behavior based on the session type and the next-hop host.

RADIUS Per Host Accounting

In SR-OS, the accounting paradigm is based on SLA profile instances yet this is at odds with traditional RADIUS authentication and accounting which is host-centric. In previous SR-OS releases, it was possible to have many hosts sharing a common SLA profile instance, and thus accounting and QoS parameters. Complications would arise with RADIUS accounting because Accounting-Start and Accounting-Stop are a function of sla-profile instance and not the hosts — this meant that some host-specific parameters (like framed-ip-address) would not be consistently included in RADIUS accounting.

Currently, dual-stack subscribers are really two different hosts sharing a single sla-profile instance. A new RADIUS accounting mode has been introduced to support multiple-host environments.

Under accounting-policy, a host-accounting command allows configurable behavior.

No Host-Accounting

In prior releases and when no host-accounting is configured, the accounting behavior is as follows:

Host-Accounting Enabled

When host-accounting is configured, additional RADIUS accounting messages are created for host activity in addition to messages for common queue accounting. The behavior is as follows:

This new behavior means certain AVP may be in either host; sla-profile instance or both accounting records.

Note that interim-acct records are not sent for hosts, only the start- and stop-accting messages.

Reduction of Host Updates for Session Accounting Start and Stop

When host-update is enabled In session accounting, a dual stack subscriber can generate multiple host update accounting messages at the start and end of a session (for example, one for the IPv4 host and two more for the IPv6 WAN and IPv6 PD hosts). Two features can be used to reduce the number of host update messages per subscriber.

The first feature delays the Start Accounting message by a configurable value and is applicable to both PPPoE and IPoE sessions. The command for configuring this feature is config>subscr-mgmt>acct-plcy>delay-start-time. The delay allows the full dual stack address assignment to be completed before triggering the accounting Start message. The Start message reports all the addresses and prefixes assigned to the subscriber at that time. Subsequent new or disconnected hosts will trigger interim host updates if enabled.

The second feature is for PPPoE sessions only and is used to reduce the number of host update messages when a dual stack PPP subscriber disconnects. The command for configuring this feature is config>subscr-mgmt>sub-prof>rad-acct>session-optimized-stop. A single accounting Stop message containing all the addresses and prefixes for the subscriber at the time is generated.

Accounting Interim Update Message Interval

The interval between two RADIUS Accounting Interim Update messages can be configured in the RADIUS accounting policy with the update-interval command, for example:

A RADIUS specified interim interval (attribute [85] Acct-Interim-Interval) overrides the CLI configured value.

By default, a random delay of 10% of the configured update-interval is added to the update-interval between two Accounting Interim Update messages. This jitter value can be configured with the update-interval-jitter to an absolute value in seconds between zero and 3600. The effective maximum random delay value is the minimum value of the configured absolute jitter value and 10% of the configured update-interval.

A value of zero will send the Accounting Interim Update message without introducing an additional random delay.

CoA Triggered Accounting Interim Update

The vendor-specific attribute (VSA) [228], Alc-Triggered-Acct-Interim, can be used in a Change of Authorization message to trigger an interim accounting message. This feature requires the accounting mode to have interim updates enabled. You can enable interim updates using, the config>subscr-mgmt>radius-acct-plcy>host-accounting interim-update command. The VSA can hold a string of up to 247 characters. The accounting interim echoes this string in the interim message under the same Alc-Triggered-Acct-Interim VSA along with Alc-Acct-Triggered-Reason = CoA-triggered. If the VSA is left blank, it will still trigger the accounting interim message with Alc-Acct-Triggered-Reason = CoA-triggered (18), but without the Alc-Triggered-Acct-Interim attribute. If the subscriber session has multiple accounting policies or modes enabled, multiple interim messages will be generated.Some CoAs, such as SLA profile or sub-profile changes, will trigger accounting update messages to be generated automatically. These CoAs can automatically generate one or more accounting interim messages. If these CoAs also include the Alc-Triggered-Acct-Interim VSA, no additional interim accounting messages will be generated. The last auto-generated accounting interim message will contain two reasons:

Class Attribute

The RADIUS class attribute helps to aid in user identification.

User identification is used to correlate RADIUS accounting messages with the given user. During the authentication process, the RADIUS authentication server inserts a class attribute into the RADIUS authenticate response message and the router echoes this class attribute in all RADIUS accounting messages.

The 7750 SR can store up to six class attributes for both RADIUS and NASREQ. Each class VSA or AVP can have a maximum of 253 characters. If the VSA or AVP contains more than 253 characters, only the first 253 characters will be stored. If there are more than six VSAs or AVPs, only the first six will be stored. This functionality is also applicable to RADIUS authentication via the ISA.

User Name

The user-name, which is used for user authentication (user-name attribute in RADIUS authentication request), can be included in RADIUS accounting messages. Per RFC 2865, when a RADIUS server returns a (different) user-name attribute, the changed user name will be used in accounting and not the originally sent user name.

Accounting-On and Accounting Off

For RADIUS servers configured in a RADIUS server policy, the accounting on/off behavior is controlled via the acct-on-off command in the radius-server-policy.

By default, no Accounting-On or Accounting-Off messages are sent (no acct-on-off).

With the acct-on-off command configured in the radius-server-policy:

The Accounting-On or Accounting-Off message is sent to the servers configured in the radius-server-policy, following the configured access-algorithm until an Accounting Response is received. If the first server responds, no message is sent to the other servers.

The Accounting-On message is repeated until an Accounting Response message is received from a RADIUS server: If after the configured retry/timeout timers for each RADIUS server in the radius-server-policy no response is received then the process starts again after a fixed one minute wait interval.

The Accounting-Off message is attempted once: If after the configured retry/timeout timers for each RADIUS server in the radius-server-policy no response is received then no new attempt is made.

It is possible to block a radius-server-policy until an Accounting Response is received from one of the RADIUS servers in the radius-server-policy that acknowledges the reception of an Accounting-On. The radius-server-policy cannot be used by applications for sending RADIUS messages until the state becomes “Not Blocked”. This is achieved with the optional “oper-state-change” flag, for example:

If multiple radius-server-policies are in use for different applications (for example, authentication and accounting) and an Accounting-On must be send for only one radius-server-policy, it is possible to tie the acct-on-off states of both policies together using an acct-on-off-group. With this configuration, it is possible to block the authentication servers until the accounting servers are available. An acct-on-off-group can be referenced by:

It is possible to force an Accounting-On or Accounting-Off message for a radius-server-policy with acct-on-off enabled using following CLI commands:

tools perform aaa acct-on [radius-server-policy policy-name] [force]

tools perform aaa acct-off [radius-server-policy policy-name] [force] [acct-terminate-cause number]

If an Accounting-On was sent to the radius-server-policy and it was acknowledged with an Accounting Response then a new Accounting-On can only be sent with the “force” flag.

If an Accounting-Off was sent to the radius-server-policy and it was acknowledged with an Accounting Response then a new Accounting-Off can only be sent with the “force” flag. The Acct-Terminate-Cause value in the Accounting-Off can be overwritten.

Use the following CLI command to display the Accounting On/Off information for a radius-server-policy:

The operational state provides following state information: The sending of the Accounting-On or Accounting-Off message is ongoing (sendAcctOn, SendAcctOff), is successfully responded (on, off) or no response received (OffNoResp).

The Session-Id is a unique identifier for each RADIUS server policy accounting Accounting-On/Accounting-Off sequence.

The Trigger field shows what triggered the Accounting On or Accounting Off message. If the radius-server-policy is part of an acct-on-off group then the group name is shown in brackets.

The Server field shows which server in the RADIUS server policy responded to the Accounting-On or Accounting-Off message.

To display the acct-on-off state of a radius-server-policy, use the command, for example:

The Acct-On-Off field indicates if the sending of Accounting-On and Accounting-Off messages is enabled or disabled. If enabled, the oper-state is displayed: state Blocked or state Not Blocked. When Blocked, the radius-server-policy cannot be used to send RADIUS messages.

To display acct-on-off-group information, use following command, for example:

RADIUS Accounting Message Buffering

When all servers in a radius-server-policy are unreachable, it is possible to buffer the Accounting Stop and Accounting Interim-Update messages for up to 25 hours. When a RADIUS server becomes reachable again then the messages in the buffer are retransmitted.

RADIUS Accounting message buffering parameters can be configured per message type, for example:

When RADIUS accounting message buffering is enabled:

When Accounting Interim-Update message buffering is enabled, it is recommended to also enable Accounting Stop message buffering. This will guarantee the message ordering per accounting session.

Use following clear command to manually delete messages from the RADIUS accounting message buffer:

# clear aaa radius-server-policy policy-name msg-buffer [acct-session-id acct-session-id]

When specifying the Acct-Session-Id, only that specific message will be deleted from the message buffer. If no Acct-Session-Id is specified, all messages for that radius-server-policy are deleted from the message buffer.

Use the following show commands to display the RADIUS accounting message buffer statistics:

Use following clear command to reset the RADIUS accounting message buffer statistics:

# clear aaa radius-server-policy policy-name statistics msg-buffer-only

Use following tools commands to display the RADIUS accounting message buffer content:

# tools dump aaa radius-server-policy policy-name msg-buffer [session-id acct-session-id]

For example:

When specifying the Acct-Session-Id, the message details are displayed.

Multiple Accounting Policies

The subscriber profile allows the user to configure a primary accounting policy with an additional accounting policy. The accounting policies are independent of each other and each policy has its own accounting mode, update interval, and include attributes. The RADIUS VSA [85] Acct-Interim-Interval attribute changes both the primary and the duplicate accounting interim update interval.

Sending an Accounting Stop Message upon a RADIUS Authentication Failure of a PPPoE Session

In scenarios where RADIUS authentication is used for PPPoE sessions, an accounting stop message can be generated to notify the RADIUS servers in case of an authentication failure.

The failure events are categorized in three categories:

Each of the categories can be enabled separately in the RADIUS authentication policy.

In the Enhanced Subscriber Management (ESM) model, the RADIUS accounting server is found after authentication and host identification as part of the subscriber profile configuration. To report authentication failures to accounting servers, an alternative RADIUS accounting policy configuration is required: local user database pre-authentication can provide the RADIUS authentication policy to be used for authentication and the RADIUS accounting policy to be used for authentication failure reporting. A duplicate RADIUS accounting policy can be specified if the accounting stop resulting from a RADIUS authentication failure must also be sent to a second RADIUS destination.

To enable local user database pre-authentication, use the user-db configuration in the capture SAP and in the group-interface. For example:

Standard and Enhanced Subscriber Management

The system can switch between standard and enhanced subscriber management modes on a per SAP basis. The Enhanced Subscriber Management mode is supported on the SR-7 and SR-12 chassis and on the ESS-7 chassis.

Some functions are common between the standard and enhanced modes. These include DHCP lease management, static subscriber host definitions and anti-spoofing. While the functions of these features may be similar between the two modes, the behavior is considerably different.

When the enhanced mode is enabled on a SAP (see Subscriber SAPs), first, the router ensures that existing configurations on the SAP do not prevent proper enhanced mode operation. If any one of the following requirements is not met, enhanced mode operation is not allowed on the SAP:

When the router successfully enables the enhanced mode, the current dynamic subscriber hosts are not touched until a DHCP message event occurs that allows re-population of the dynamic host information. Thus, over time, the dynamic subscriber host entries are moved from SAP-based queuing and SAP-based filtering to subscriber-based queuing and filtering. In the event that a dynamic host event cannot be processed due to insufficient resources, the DHCP ACK message is discarded and the previous host lease information is retained in the system.

Models

PPPoE Host

For PPPoE, the ESR suggests the IPv6CP protocol to the client during the session setup phase if the appropriate attributes have been returned by the RADIUS server on authentication. The RADIUS attribute that indicates the setup of a PPPoE host is Framed-IPv6-Prefix, which should contain a /64 prefix for the client.

When a PPPoE host has successfully completed the IPv6CP negotiation, the ESR will transmit a Router Advertisement to the PPPoE host containing the suggested prefix and any other options that are configured. The client may use this information to pick one or more addresses from the suggested prefix; all addresses within the prefix are forwarded towards the client.

Alternatively, the Recursive DNS Server (RDNSS) Option as defined in RFC 6106, IPv6 Router Advertisement Options for DNS Configuration, can be included in IPv6 Router Advertisements for DNS name resolution of IPv6 SLAAC hosts. The following CLI command includes the DNS info in IPv6 Router Advertisements for SLAAC hosts and sets the RDNSS liftetime:

config>service>ies>sub-if>grp-if>ipv6>rtr-adv

config>service>vprn>sub-if>grp-if>ipv6>rtr-adv

[no] dns-options

[no] include-dns - Set/reset inclusion of the RDNSS server

option 25 on this group-interface

[no] rdnss-lifetime – Maximum time the RDNSS address is valid

in this group-interface

The source for DNS information to be included in Router Advertisements for IPv6 SLAAC hosts, can be (listed in priority order):

1. Local User Database IPv6 options:
   configure subscriber-mgmt local-user-db <ludb-name> dhcp|ppp host <host-name> options6 dns-server <ip-address> [<ip-address>...(up to 4 max)]
2. RADIUS attributes [26-6527-105] Alc-Ipv6-Primary-Dns and [26-6527-106] Alc-Ipv6-Secondary-Dns
3. Default IPv6 DNS Server configured at the group interface:
   configure service ies|vprn <svc-id> subscriber-interface <sub-int-name> ipv6 default-dns <ipv6-address> [secondary <secondary-ipv6-address>]

Note: A default IPv6 server configuration at the group interface is a last resort IPv6 DNS info that can be used for IPoEv6 hosts (IA_NA, IA_PD and SLAAC) and PPPoEv6 hosts (IA_NA, IA_PD and SLAAC).

Setup

IPv6 ESM hosts are only supported in the Routed CO model (both VPRN and IES).

At the ipv6 node under the subscriber interface level, the length of the prefixes that are offered is defined through the delegated-prefix-length option. This setting is fixed for the subscriber interface and can not be changed once subscriber prefixes are defined.

Subscriber prefixes define the ranges of addresses that are offered on this subscriber interface. By default only these subscriber prefixes are exported to the routing protocols to keep the routing tables small. There are three types of subscriber interfaces:

The IPv6 node under the group interface contains the DHCPv6 proxy configuration and the router advertisement configuration.

Behavior

Delegated-Prefix-Length

The delegated prefix length (DPL) is applicable to subscriber-hosts with IPv6 Prefix (IA-PD) assigned via DHCPv6 Server. IPv6 Prefix is more akin to a route then it is to an IP address. The length of the prefix plays crucial role in forwarding decisions, antispoofing, and prefix assignment via DHCPv6 pools in the local DHCPv6 Server.

The structure of an IPv6 prefix is shown in Figure 64.

Figure 64:  IPv6 Prefix 

For example, a DHCPv6 server prefix pool contains an aggregated (configured) IPv6 prefix from which the delegated prefixes will be carved out. In Figure 64 this aggregated IPv6 prefix has length of /48. In addition, the DHCPv6 server needs to know the length of the delegated prefix (in the above case /60). These two values are marking the boundary within which a unique delegated prefix will be selected. This is represented by the purple area in Figure 64.

The delegated prefix length can be obtained via:

Alternatively, the entire prefix, including the DPL can be returned via LUDB.

DHCPv6 Relay Agent

A DHCPv6 Relay Agent can support a 7x50 DHCPv6 local server (same or remote chassis) and a third party DHCPv6 external server.

An incoming DHCPv6 client message is relayed within the Relay-Forward message specified in RFC 3315. If the server responds with a valid address/prefix, the ESM process attempts to install it. If it fails, the DHCPv6 Relay Agent sends an explicit RELEASE to the server. There is no retransmission of DHCPv6 Relay-Forwards in the case of failure – it requires the client to re-start or re-send the original DHCPv6 message.

A Lightweight DHCPv6 Relay Agent may insert Relay Agent Information including the Interface ID option between the DHCPv6 client and the DHCPv6 Relay Agent.

Additional Relay Agents (non-LDRA) between the DHCPv6 client and the DHCPv6 Relay Agent are not supported.

DHCPv6 Relay to Third Party DHCPv6 External Server

When the DHCPv6 Relay Agent is relaying to a third party DHCPv6 external server, following conditions should be met:

Following information is available to the third party DHCPv6 server in a Vendor-Specific-Information-Option (17) included in the Relay-Forward message:

DHCPv6 Local Server

A local DHCPv6 pool server for both addresses (IA_NA) and prefixed (IA_PD) manages the address and prefixes sent to either routing gateways or hosts.

Because IPv6 home networks lack NAT, the IPv6 addresses delegated to a routing gateway are in turn assigned to hosts in the home. These addresses are assigned with reasonably long (but configurable) lifetimes such that the loss of the WAN connection will not result in the IPv6 hosts in the LAN losing their IPv6 addresses. One consequence of these long lifetimes is that the IPv6 hosts will retain any IPv6 address provided the valid-lifetime is greater than zero. Should an operator delegate a prefix and then at a later time delegate a second IPv6 prefix, a host may end up with two or more valid prefixes. This situation plays havoc with IPv6 source address selection and may result in impaired service.

To overcome the problems of multiple IPv6 prefixes in the home, the operator must ensure that the individual subscriber has the same IPv6 prefix even across modem reboots (that is, if a subscriber session is destroyed and later re-created, an attempt should be made to use the previously delegated prefix). In release 8.0, the operator used RADIUS for all address and prefix assignment, but in release 9.0, with the introduction of the local DHCPv6 server, it requires the 7750 to process and maintain some state even after a session disconnects.

For the DHCPv6 local server to function, a DHCPv6 relay or proxy function must also operate alongside ESM. For the purposes of this document, to relay means to implement a DHCPv6 Relay as indicated in RFC 3315 : a relay encapsulates the client DHCP message within a DHCP Relay-Forward message and unicasts it to a specified destination.

A proxy is an internal concept. Unlike a DHCPv6 relay, the DHCPv6 proxy does NOT encapsulate the client message in a Relay-Forward, nor does it send packets towards the Local DHCPv6 Server. The DHCPv6 proxy is exclusively used as an interface between the RADIUS Access-Accept or local user database lookup and the DHCPv6 client in the consumer device.

The use of the DHCPv6 relay or proxy function depends on the attributes returned from authentication phase (RADIUS or LUDB).

Note: If IPv6 DNS parameters are returned in RADIUS AND a pool is specified then the DNS parameters are ignored. It is the DHCPv6 server that will need to reply with appropriate DNS servers.

Dynamic Tables

To support all processing for Enhanced Subscriber Management, several tables are maintained in the router (Figure 65).

Figure 65:  Enhanced Subscriber Management Dynamic Tables 

Instantiating a New Host

When a DHCP ACK is received for a new subscriber host on a particular SAP:

If this is the first host of a subscriber, an HQoS scheduler is instantiated using the ingress and egress scheduler policies referred to in the subscriber profile. Otherwise, if the subscriber profile of the new host equals the subscriber profile of the existing subscriber, the new host is linked to the existing scheduler. If the subscriber profile is different from the subscriber profile of the existing subscriber, a new scheduler is created and all the hosts belonging to that subscriber are linked to this new scheduler. Notice that the new subscriber profile will not conflict with the subscriber profile provisioned for a static host or non-sub-traffic under the same SAP.

If this is the first host of a subscriber on a particular SAP using a particular SLA profile, an SLA profile instance is generated and added to the SLA profile instance table. This includes instantiating a number of queues, according to the ingress and egress QoS profiles referred to in SLA profile, optionally with some specific overrides defined in the SLA profile. Otherwise the host is linked to the existing SLA profile instance for this subscriber on this SAP.

Note: Any QoS and IP filter policies defined on the SAP are still processed even if Enhanced Subscriber Management is enabled on the SAP. For IPv4 traffic that is dropped due to anti-spoofing, counters, logging, and mirroring can be used. All other Layer 2 traffic that is never blocked by anti-spoofing can be processed by applying a QoS policy on the SAP and can still be classified differently, by the dot1p value.

Note: If insufficient hardware resources (queues) or software resources (profile instances) are available to support the new host, the DHCP ACK is dropped and an event is generated.

Packet Processing for an Existing Host

Whenever an IP packet arrives on a subscriber-facing SAP on which Enhanced Subscriber Management is enabled, a lookup is done in the subscriber host table using as the index the SAP, source IP address, and source MAC address.

Functionality

ESM lockout is supported for dual-stack PPPoE hosts, L2TP LAC hosts, dual-stack IPoE hosts, and ARP hosts. ESM Lockout tracks the following:

During lockout, authentication and ESM host creation is suppressed. A lockout context will be created when a client first enters lockout. The context maintains state and timeout parameters for the lockout. If a lockout policy is configured for the underlying SAP for a host that has failed authentication or host creation, the host enters lockout for the configured minimum time (1 to 86400 seconds). When the lockout time expires, normal authentication and ESM host creation will be resumed on relevant PPP or DHCP messages. In case of another failure, the host will again enter the lockout state. The lockout time for the host on each failure will be exponentially increased up to the configured maximum time (1 to 86400 seconds). The lockout time for a client will be reset to the configured minimum value, and the corresponding lockout context will be deleted, if there is no authentication (and host creation) failure within a configured amount of time that needs to elapse after the client initially enters lockout. This time is called the lockout-reset-time.

The host identification for lockout includes <SAP, MAC@, circuit ID, remote ID>.

ANCP

Access Node Control Protocol Management (ANCP) can provide the following information to the router:

When ANCP is used with Enhanced Subscriber Management (ESM), a new string ancp-string can be returned from the Python script or from RADIUS. If not returned it defaults to the subscriber ID.

ANCP version 0x31 and 0x32 are both supported and will be auto detected at the start of each ANCP session. Within version 0x32, partitioning is also supported.

Multiple partitions from the same Access Node are also supported. If partitions are used, they are automatically detected during the start of an ANCP session.

Static ANCP Management

As depicted in Figure 67, a DSLAM is connected to an aggregation network that is connecting the DSLAM to a BRAS. ANCP is used to provide SAP level rate management. The DSLAM in this application maintains multiple ANCP connections. The primary connection is to the BRAS, providing rate and OAM capabilities while the secondary is to the router to provide rate management.

7750 SR and 7450 ESS:

Figure 67:  Static ANCP Management Example 

General Switch Management Protocol Version 3 (GSMPv3)

General Switch Management Protocol version 3 (GSMPv3) is a generic protocol that allows a switch controller node to establish and maintain connections with one or more nodes to exchange operational information. Several extensions to GSMPv3 exist in the context of broadband aggregation. These extensions were proposed to allow GSMPv3 to be used in a broadband environment as additional information is needed to synchronize the control plane between access nodes (such as DSLAMs) and broadband network gateways (such as BRAS).

In the TPSDA framework, nodes fulfill some BRAS functionality, where per subscriber QoS enforcement is one of the most important aspects. To provide accurate per-subscriber QoS enforcement, the network element not only knows about the subscriber profile and its service level agreement but it is aware of the dynamic characteristics of the subscriber access circuit.

The most important parameters in this context are the subscriber-line capacity (DSL sync-rate) and the subscriber's channel viewership status (the actual number of BTV channels received by the given subscriber in any point in time). This information can be then used to adjust parameters of aggregate scheduling policy.

Besides, the above-mentioned information, GSMPv3 can convey OAM information between a switch controller and access switch. The node can operate in two roles:

The DSL forum working documents recommends that a dedicated Layer 2 path (such as, a VLAN in an Ethernet aggregation network) is used for this communication to provide a certain level of security. The actual connection between DSLAM and BRAS is established at TCP level, and then individual messages are transported.

DHCP Release Messages

The node supports DHCP release messages. A DHCP release message removes state from the DHCP server when the node rejects ACKs or removes hosts.

DHCP Client Mobility

Client mobility allows the node to use host monitoring (SHCV, ANCP, split DHCP) to remove network and server state when a host is removed locally. This allows for MAC addressed learned and pinned to move based on policy parameters.

Subscriber Host Connectivity Verification (SHCV) configuration is mandatory. This allows clients to move from one SAP to another SAP in the same service. This is only applicable in a VPLS service and group interfaces.

The first DHCP message on the new SAP with same MAC address (and IP address for group-interfaces) will trigger SHCV and will always be discarded.

SHCV will check that the host is no longer present on the SAP where the lease is currently populated to prevent spoofing. When SHCV detects that the host is not present on the original SAP, the lease-state will be removed. The next DHCP message on the new SAP can initiate the host.

DHCP Lease Control

DHCP lease control allows the node to be configured to present a different lease to the client. This can be used to monitor the health of the client.

Python Language and Programmable Subscriber Configuration Policy (PSCP)

PSCP is an identification mechanism using the Python scripting language. The PSCP references a Python script that can use regular expressions to derive the sub-ident-string, sub-profile-string and sla-profile-string from the DHCP response. A tutorial of regular expressions is beyond the scope of this guide, and can be found on the Internet (refer to http://www.amk.ca/python/howto/regex/).

A tutorial of Python is beyond the scope of this guide but can be found on the Internet (refer to http://www.python.org/).

Example scripts, using some regular expressions, can be found in Sample Python Scripts. Additional information about the service manager scripting language, see Python Script Support for ESM.

One or more scripts can be written by the operator and stored centrally on a server (in a location accessible by the router). They are loaded into each router at bootup.

Note that if a centrally stored script is changed, it is not automatically re-loaded onto the router. The reload must be forced by executing the shutdown / no shutdown commands on the affected URL(s).

Determining the Subscriber Profile and SLA Profile of a Host

Figure 69 describes the data flow while determining which subscriber profile and SLA profile to use for a certain subscriber host based on a snooped/relayed DHCP ACK for that subscriber host.

Figure 69:  Data Flow in Determining Subscriber Profile and SLA Profile 

An incoming DHCP ACK (relayed or snooped) is processed by the script provisioned in the sub-ident-policy defined in the SAP on which the message arrived. This script outputs one or more of the following strings:

These strings are used for a lookup in one or more maps to find the names of the sub-profile and sla-profile to use. If none of the maps contained an entry for these strings, the names will be determined based on a set of defaults.

Only when the names for both the sub-profile and sla-profile are known, the subscriber host can be instantiated. If even no default is found for either profile, the DHCP ACK is dropped and the host will not gain network access.

Determining the Subscriber Profile

All hosts (devices) belonging to the same subscriber will be subject to the same HQoS processing. The HQoS processing is defined in the sub-profile. A sub-profile refers to an existing scheduler policy and offers the possibility to overrule the rate of individual schedulers within this policy.

Because all subscriber hosts of one subscriber use the same scheduler policy instance, they must all reside on the same I/O module.

The figure below shows how the sub-profile is derived, based on the sub-ident string, the sub-profile string and/or the provisioned data structures. The numbers associated with the arrows pointing toward the subscriber profiles indicate the precedence of the checks.

Figure 70:  Determining the Subscriber Profile 

Determining the SLA Profile

For each host that comes on-line, the router also needs to determine which SLA profile to use. The SLA profile will determine for this host:

The SLA profile also has a host-limit attribute which limits the number of hosts (belonging to the same subscriber) on a certain SAP that can be using this SLA profile.

The classification and the queue mapping are shared by all the hosts on the same forwarding complex that use the same QoS policy (by their SLA profile).

The queues/policers are shared by all the hosts (of the same subscriber) on the same SAP that are using the same SLA profile. In other words, queues/policers are instantiated when, on a given SAP, a host of a subscriber is the first to use a certain SLA profile. This instantiation is referred to as an SLA profile instance. Ingress queues can be parented to a scheduler referenced in the ingress of a subscriber profile. Egress queues can be parented to a scheduler referenced in the egress of a subscriber or SLA profile, or to a port scheduler.

A scheduler policy can be applied to the egress an SLA profile, allowing its schedulers to be the parent for its queues and for its tier 1 schedulers to be parented to a scheduler in a scheduler policy applied to the egress of a subscriber profile or a vport, or to a port scheduler applied to a port or vport. Configuring scheduler overrides is allowed for SLA profile egress schedulers. The configuration of a scheduler policy in the egress of an SLA profile is supported for all host types only on Ethernet interfaces on FP2 and higher hardware. It is not supported for ESM over MPLS pseudowires, nor is HQoS adjustment and host tracking supported on its schedulers.

The following show/monitor/clear commands are available related to the SLA profile scheduler:

The show qos scheduler-hierarchy subscriber command (shown above) displays the scheduler hierarchy with the SLA profile scheduler as the root. Note that if the SLA profile scheduler is orphaned (that is when the scheduler has a parent which does not exist) then the hierarchy is only shown when the show command includes the sla-profile and sap parameters.

Note: If the SLA profile scheduler is orphaned (that is when the scheduler has a parent which does not exist) then the hierarchy is only shown when the show command includes the sla-profile and SAP parameters.

The figure below shows a graphical description of how the SLA profile is derived based on the subscriber identification string, the SLA profile string and the provisioned data structures. The numbers on the arrows towards the SLA profile indicate the priority of the provisioning (the lower number means the higher priority).

Figure 71:  Determining the SLA Profile 

Sub-id Identifiers

The sub-id can be based on any combination of the following identifiers:

Dual Stack Hosts

Autogeneration of sub-id names for subscribers with a single dual stack hosts (IPoE and PPPoE) is enabled by default by not explicitly provisioning anything for the def-sub-id. The sub-id name would be semi-randomly generated based on the <mac, sap-id, session-id> for PPPoE hosts and the <mac, sap-id> combination for IPoE host.

Mixing Hosts with Auto-Generated IDs and non Auto-Generated IDs

Hosts with different sub-id names but identical auto-sub-id keys are not linked into the same subscriber. Such scenarios can arise with hosts with the same auto-sub-id keys but different methods for obtaining the sub-id name. For example, one host relying on auto-generated sub-id name while the other is using explicit configuration methods (sap-id, string, RADIUS or LUDB). If the auto-generated sub-id name and explicit sub-id name are the same, the host will be tied into the same subscriber.

For example:

The default auto-sub-id for the following two hosts are <mac, sap-id>.

Host X on SAP 1/1/1:1 with MAC 00:00:00:00:00:01 obtains sub-id through RADIUS.

Host Y on SAP 1/1/1:1 with MAC 00:00:00:00:00:01 has sub-id auto-generated.

Regardless of which host comes up first, those two hosts at the end will belong two different subscribers as long as their sub-ids are different.

PPPoA/PPPoEoA Considerations

PPPoA/PPPoEoA hosts will adhere to the same rules as PPPoE. Fields that are supported in PPPoE but not PPPoA/PPPoEoA will be simply ignored.

Fields that are not supported in PPPoA are:

Fields that are most likely not applicable to PPPoEoA are:

Deployment Considerations

The following is a possible deployment example scenario.

Assume the following cases:

In the first case where RADIUS returns the sub-id string, the following will occur:

In the second case, the effects are the following:

Example:

1/1/1:100 for PPPoE

AC:AB:AA:AD:AE:AE-AN-id eth 1/1/1/1:2 for IPoE

(circuit-ID format is: Access-Node-Identifier atm slot/port:vpi.vci or Access-Node-Identifier eth slot/port:[vlan-id]).

Note that the circuit-ID can itself be 63B in length whereas the length of the sub-id name is limited to 32 Bytes. So in the above case, the sub-id name length would be 38 Bytes (>32B) and the host instantiation would fail.

Caveats

Only a single combination of the subscriber fields used to auto generate sub-id is allowed per host type (IPoE or PPPoE) and per chassis. In case that the combination of the fields needs to be changed, the existing subscribers with an auto-generated sub-id must be manually terminated. Considering that remote termination of the IPoE subscribers by DHCP server is not supported by all DHCP client vendors through FORCERENEW DHCP message (RFC 3203), changing the subscriber fields while subscribers with auto generated sub-id are active should be avoided.

QoS Parameters in Different Profiles

QoS aspects for subscribers and hosts can be defined statically on a SAP or dynamically using

Enhanced Subscriber Management. For example, in a VLAN-per-service model, different services belonging to a single subscriber are split over different SAPs, and thus the overall QoS (such as a scheduler policy) of this subscriber must be assigned using Enhanced Subscriber Management.

QoS parameters are shared among the subscriber profile and SLA profile as follows:

The primary use of the subscriber profile is to define the ingress and egress scheduler policies/ policer-control-policies used to govern the aggregate SLA for all hosts associated with a subscriber. To be effective, the queues/policers defined in the SLA profile’s QoS policies will reference a scheduler/arbiter from the scheduler policy/policer-control-policy respectively as their parent.

QoS Policy Overrides

Generic QoS queue/policer parameters could be specified for the SAP in a QoS policy and overridden for some customers by queue/policer parameters defined in the SLA profile. This allows for a single SAP ingress and SAP egress QoS policy to be used for many subscribers, while providing individual subscriber parameters for queue/policer operation.

Subscriber HQoS

Hierarchical QoS (HQoS) corresponds to scheduling bandwidth distribution to queues/schedulers and is applied using scheduler policies at ingress and egress of the subscriber profile for a subscriber, and at egress in the SLA profile for a host, together with a port scheduler at both the port and vport level.

Each scheduler policy can contain up to three tiers of schedulers with lower level schedulers being able to parent to higher level schedulers in the same scheduler policy.

Queues can parent to any scheduler in their related scheduler policy hierarchy (except vport at egress) and also at the egress to a port scheduler.

Schedulers can parent to any higher level scheduler in their related scheduler policy hierarchy and, at the egress to a port scheduler configured within the port or vport. When an egress port scheduler is used, an aggregate rate limit can be applied at the subscriber profile and vport levels instead of using a scheduler. To extend the hierarchy further at egress, a tier 1 scheduler within a scheduler policy can parent to any scheduler in a scheduler policy at a higher level.

The scheduling levels are comprised of:

The ingress hierarchical parenting relationship options are shown in Figure 72.

Figure 72:  Ingress Scheduling Hierarchy Options 

The egress hierarchical parenting relationship options are shown in Figure 73. Note that not all combinations can be configured concurrently, and some uses of port parent could be equally achieved using a scheduler parent and a child parent-location.

Figure 73:  Egress Scheduling Hierarchy Options 

The parent command is used to specify the name of the parent scheduler when parenting a queue or scheduler, together with the level/cir-level and weight/cir-weight at which to connect.

The location of the parent scheduler (in which applied scheduler policy it exists) for a queue defaults to a scheduler in the subscriber ingress or egress scheduler policy. Parents of schedulers themselves must be explicitly configured and by default must be within the same scheduler policy.

At egress, the scheduler parenting relationship is determined using the parent-location command:

By default, egress queues parent to any scheduler in subscriber egress scheduler policy.

Egress queues can parent to any scheduler within the scheduler policy applied to the egress of an SLA profile.

By default, a tier 1 scheduler in the scheduler policy is not allowed to be parented to another scheduler.

A tier 1 scheduler in the scheduler policy applied to the egress of an SLA profile can parent to a scheduler applied to the egress of a subscriber profile.

A tier 1 scheduler in the scheduler policy applied to the egress of a subscriber profile can parent to a scheduler applied to the egress of a Vport.

The configuration of a parent-location and frame-based accounting in a scheduler policy is mutually exclusive in order to ensure consistency between the different scheduling levels.

Note that the parent-location command is supported only on Ethernet interfaces on FP2 and higher hardware. It is not supported for ESM over MPLS pseudowires.

Both egress queues and egress schedulers can port parent using directly to different levels/cir-levels, with different weights/cir weights, to a port egress port scheduler. Egress schedulers can also port parent directly to different levels/cir-levels, with different weights/cir weights, to a vport egress port scheduler.

Subscriber CFHP

Class Fair Hierarchical Policing (CFHP) corresponds to the policing control of traffic by policers/arbiters. This uses policer control policies and can be applied for ingress and egress capacity control for the subscriber in the subscriber profile.

Each policer control policy can contain up to three tiers of arbiters with lower level arbiters being able to parent to higher level abiters in the same scheduler policy.

Policers can parent to any arbiter in their related policer control policy hierarchy.

The policing levels are comprised of:

Note: Ingress policed traffic uses the shared policer-output-queues to access the switch fabric. At egress, the policed traffic accesses the egress port through a queue group queue (by default the policer-output-queues queue group, though user configurable queue groups can also be used) or a locally configured subscriber queue.

The ingress hierarchical parenting relationship options are shown in Figure 74.

Figure 74:  Ingress Policing Hierarchy Options 

The egress hierarchical parenting relationship options are shown in Figure 75.

Figure 75:  Egress Policing Hierarchy Options 

The parent command is used to specify the name of the parent arbiter when parenting a policer or arbiter, together with the level and weight at which to connect.

ATM/Ethernet Last-Mile Aware QoS for Broadband Network Gateway

This feature allows the user to perform hierarchical scheduling of subscriber host packets such that the packet encapsulation overhead and ATM bandwidth expansion (when applicable) due to the last mile for each type of broadband session, that is, PPPoEoA LLC/SNAP and VC-Mux, IPoE, IPoEoA LLC/SNAP and VC-Mux, etc., is accounted for by the 7x50 acting as the Broadband Network Gateway (BNG).

The intent is that the BNG distributes bandwidth among the subscriber host sessions fairly by accounting for the encapsulation overhead and bandwidth expansion of the last mile such that packets are less likely to be dropped downstream in the DSLAM DSL port.

The last mile encapsulation type can be configured by the user or signaled using the Access-loop-encapsulation sub-TLV in the Vendor-Specific PPPoE Tags or DHCP Relay Options as per RFC 4679.

Furthermore, this feature allows the BNG to shape the aggregate rate of each subscriber and the aggregate rate of all subscribers destined to a given DSLAM to prevent congestion of the DSLAM. The subscriber aggregate rate is adjusted for the last mile overhead. The shaping to the aggregate rate of all subscribers of a given destination DSLAM is achieved via a new scheduling object, referred to as Virtual Port or vport in CLI, which represents the DSLAM aggregation node in the BNG scheduling hierarchy

Broadband Network Gateway Application

An application of this feature in a BNG is shown in Figure 76.

Figure 76:  BNG Application 

Residential and business subscribers use PPPoEoA, PPoA, IPoA, or IPoEoA based session over ATM/DSL lines. Each subscriber host can use a different type of session. Although Figure 1 illustrates ATM/DSL as the subscriber last mile, this feature supports both ATM and Ethernet in the last mile.

A subscriber SAP is auto-configured via DHCP or RADIUS authentication process, or is statically configured, and uses a Q-in-Q SAP with the inner C-VLAN identifying the subscriber while the outer S-VLAN identifies the Broadband Service Access Node (BSAN) which services the subscriber, i.e., the DSLAM. The SAP configuration is triggered by the first successfully validated subscriber host requesting a session. Within each subscriber SAP, there can be one or more hosts using any of the above session types. The subscriber SAP terminates on an IES or VPRN service on the BNG. It can also terminate on a VPLS instance.

When the 7750 BNG forwards IP packets from the IP-MPLS core network downstream towards the Residential Gateway (RG) or the Enterprise Gateway (EG), it adds the required PPP and Ethernet headers, including the SAP encapsulation with C-VLAN/S-VLAN. When the BSAN node receives the packet, it strips the S-VLAN tag, strips or overwrites the C-VLAN tag, and adds padding to minimum Ethernet size if required. It also adds the LLC/SNAP or VC-mux headers plus the fixed AAL5 trailer and variable AAL5 padding (to next multiple of 48 bytes) and then segments the resulting PDU into ATM cells when the last mile is ATM/DSL. Thus the packet size will undergo a fixed offset due to the encapsulation change and a variable expansion due to the AAL5 padding when applicable. Each type of subscriber host session will require a different amount of fixed offset and may require a per packet variable expansion depending of the encapsulation used by the session. The BNG node learns the encapsulation type of each subscriber host session by inspecting the Access-loop-encapsulation sub-TLV in the Vendor-Specific PPPoE Tags as specified in RFC 4679. The BNG node must account for this overhead when shaping packets destined to subscriber.

Queue Determination and Scheduling

Figure 77 illustrates the queuing and scheduling model for a BNG using the Ethernet/ATM last-mile aware QoS feature.

Figure 77:  BNG Queuing and Scheduling Model 

A set of per FC queues are applied to each subscriber host context to enforce the packet rate within each FC in the host session as specified in the subscriber’s host SLA profile. A packet is stored in the queue corresponding the packet’s FC as per the mapping of forwarding class to queue-id defined in the sap-egress QoS policy used by the host SLA profile. In the BNG application however, the host per FC queue packet rate is overridden by the rate provided in the RADIUS access-accept message. This rate represents the ATM rate that will be seen on the last mile, that is, it includes the encapsulation offset and the per packet expansion due to ATM segmentation into cells at the BSAN.

In order to enforce the aggregate rate of each destination BSAN, a scheduling node, referred to as virtual port, and vport is in the CLI. The vport operates exactly like a port scheduler with the difference that multiple vport objects can be configured on the egress context of an Ethernet port. The user adds a vport to an Ethernet port using the following command:

CLI Syntax:

configure>port>ethernet>access>egress>vport ‘vport-name create

The vport is always configured at the port level even when a port is a member of a LAG. The vport name is local to the port it is applied to but must be the same for all member ports of a LAG. It however does not need to be unique globally on a chassis.

CLI Syntax:

configure>port>ethernet>access>egress>vport vport-name create

The vport is always configured at the port level even when a port is a member of a LAG. The vport name is local to the port it is applied to but must be the same for all member ports of a LAG. It however does not need to be unique globally on a chassis.

The user applies a port scheduler policy to a vport using the following command:

CLI Syntax:

configure>port>ethernet>acess>egress>vport>port-scheduler-policy port-scheduler-policy-name

A vport cannot be parented to the port scheduler when it is using a port scheduler policy itself. It is thus important the user ensures that the sum of the max-rate parameter value in the port scheduler policies of all vport instances on a given egress Ethernet port does not oversubscribe the port’s hardware rate. If it does, the scheduling behavior degenerates to that of the H/W scheduler on that port. A vport which uses an agg-rate can be parented to a port scheduler. This is explained in Applying Aggregate Rate Limit to a Vport. Note that the application of the agg-rate rate, port-scheduler-policy and scheduler-policy commands under a vport are mutually exclusive.

Each subscriber host queue is port parented to the vport which corresponds to the destination BSAN using the existing port-parent command:

CLI Syntax:

configure>qos>sap-egress>queue>port-parent [weight weight] [level level] [cir-weight cir-weight] [cir-level cir-level]

This command can parent the queue to either a port or to a vport. These operations are mutually exclusive in CLI as explained above. When parenting to a vport, the parent vport for a subscriber host queue is not explicitly indicated in the above command. It is determined indirectly. The determination of the parent vport for a given subscriber host queue is described in Vport Determination and Evaluation.

Furthermore, the weight (cir-weight) of a queue is normalized to the sum of the weights (cir-weights) of all active subscriber host queues port-parented at the same priority level of the vport or the port scheduler policy. Since packets of ESM subscriber host queues are sprayed among the link of a LAG port based on the subscriber-id, it is required that all subscribers host queues mapping to the same vport, such as having the same destination BSAN, be on the same LAG link so that the aggregate rate towards the BSAN is enforced. The only way of achieving this is to operate the LAG port in active/standby mode with a single active link and a single standby link.

The aggregate rate of each subscriber must also be enforced. The user achieves this by applying the existing agg-rate-limit command to the egress context of the subscriber profile:

CLI Syntax:

configure>subscriber-mgmt>sub-profile>egress>agg-rate-limit agg-rate

In the BNG application however, this rate is overridden by the rate provided in the RADIUS access-accept message. This rate represents the ATM rate that will be seen on the last mile, that is, it includes the encapsulation offset and the per packet expansion due to ATM segmentation into cells at the BSAN.

Weighted Scheduler Group

The existing port scheduler policy defines a set of eight priority levels with no ability of grouping levels within a single priority. In order to allow for the application of a scheduling weight to groups of subscriber host queues competing at the same priority level of the port scheduler policy applied to the vport, or to the Ethernet port, a new group object is defined under the port scheduler policy:

CLI Syntax:

configure>qos>port-scheduler-policy>group group-name rate pir-rate [cir cir-rate]

Up to eight groups can be defined within each port scheduler policy. One or more levels can map to the same group. A group has a rate and optionally a cir-rate and inherits the highest scheduling priority of its member levels. For example, the scheduler group shown in the vport consists of level priority 3 and level priority 4. It thus inherits priority 4 when competing for bandwidth with the standalone priority levels 8, 7, and 5.

In essence, a group receives bandwidth from the port or from the vport and distributes it within the member levels of the group according to the weight of each level within the group. Each priority level will compete for bandwidth within the group based on its weight under congestion situation. If there is no congestion, a priority level can achieve up to its rate (cir-rate) worth of bandwidth.

The mapping of a level to a group is performed as follows:

CLI Syntax:

configure>qos>port-scheduler-policy>level priority-level rate pir-rate [cir cir-rate] group group-name [weight weight-in-group]

Note: CLI will enforce that mapping of levels to a group are contiguous. In other words, a user would not be able to add priority level to group unless the resulting set of priority levels is contiguous.

When a level is not explicitly mapped to any group, it maps directly to the root of the port scheduler at its own priority like in existing behavior.

Signaling of Last Mile Encapsulation Type

A subscriber host session can signal one of many encapsulation types each with a different fixed offset in the last mile. These encapsulation types are described in RFC 4679 and are illustrated in Figure 78 and Figure 79. The BNG node learns the encapsulation type of each subscriber host session by inspecting the Access-loop-encapsulation sub-TLV in the Vendor-Specific PPPoE Tags as specified in RFC 4679.When Ethernet is the last mile, the encapsulation type will result in a fixed offset for all packet sizes. When ATM/DSL is the last mile, there will be an additional expansion due to AAL5 padding to next multiple of 48 bytes and which varies depending on the packet size.

Both ATM and Ethernet access using PPP encapsulation options are supported in the software and hardware based implementations. Thus both provide support for the Access-loop-encapsulation sub-TLV in the Vendor-Specific PPPoEv4/PPPoEv6 Tags with the ATM encapsulation values and Ethernet encapsulation values.

ATM and Ethernet access using IP encapsulation are only supported using default encapsulation offset configuration in the subscriber profile in the software based implementation. Support for signaling the Access-loop-encapsulation sub-TLV in the DHCPv4/DHCPv6 Relay Options is included in the hardware based implementation. There is no support for DHCPv6 relay options.

Figure 78:  Subscriber Host Session Encapsulation Types 

Figure 79:  Access-Loop-Encapsulation Sub-TLV 

The operational last-mile values for hosts on the same sap, having the same SLA profile are displayed in following the show-command:

CLI Syntax:

show>service active-subscribers>ale-adjust

The data-link can have values: atm, other and unknown. If no offset is supplied it will be set to unknown. Other is used when the data-link is non-atm, otherwise it will state atm.

Operational per-queue values can also be found in the show-command:

CLI Syntax:

show>qos>scheduler-hierarchy

Here, one can see whether the queue is operating in last-mile mode. Note that this command is not available on HSMDAv2,

Last Mile ATM

*A:Dut-C# /show service active-subscribers ale-adjust

===============================================================================

Active Subscriber Access Loop Encapsulation adjustment

===============================================================================

Subscriber

SAP SLA profile

Data-link Offset(bytes)

-------------------------------------------------------------------------------

hpolSub81

1/1/11:2000.1 hpolSlaProf1

atm -10

-------------------------------------------------------------------------------

No. of Access Loop Encapsulation adjustments: 1

===============================================================================

*A:Dut-C# show qos scheduler-hierarchy subscriber "hpolSub81"

===============================================================================

Scheduler Hierarchy - Subscriber hpolSub81

===============================================================================

Ingress Scheduler Policy:

Egress Scheduler Policy :

-------------------------------------------------------------------------------

Root (Ing)

|

No Active Members Found on slot 1

Root (Egr)

| slot(1)

|--(Q) : Sub=hpolSub81:hpolSlaProf1 2000->1/1/11:2000.1->8->ATM (Port 1/1/11)

|

|--(Q) : Sub=hpolSub81:hpolSlaProf1 2000->1/1/11:2000.1->7->ATM (Port 1/1/11)

|

|--(Q) : Sub=hpolSub81:hpolSlaProf1 2000->1/1/11:2000.1->6->ATM (Port 1/1/11)

|

|--(Q) : Sub=hpolSub81:hpolSlaProf1 2000->1/1/11:2000.1->5->ATM (Port 1/1/11)

|

|--(Q) : Sub=hpolSub81:hpolSlaProf1 2000->1/1/11:2000.1->4->ATM (Port 1/1/11)

|

|--(Q) : Sub=hpolSub81:hpolSlaProf1 2000->1/1/11:2000.1->3->ATM (Port 1/1/11)

|

|--(Q) : Sub=hpolSub81:hpolSlaProf1 2000->1/1/11:2000.1->2->ATM (Port 1/1/11)

|

|--(Q) : Sub=hpolSub81:hpolSlaProf1 2000->1/1/11:2000.1->1->ATM (Port 1/1/11)

|

Last Mile Ethernet

*A:Dut-C# show service active-subscribers ale-adjust

===============================================================================

Active Subscriber Access Loop Encapsulation adjustment

===============================================================================

Subscriber

SAP SLA profile

Data-link Offset(bytes)

-------------------------------------------------------------------------------

hpolSub81

1/1/11:2000.1 hpolSlaProf1

other +12

-------------------------------------------------------------------------------

No. of Access Loop Encapsulation adjustments: 1

===============================================================================

*A:Dut-C# show qos scheduler-hierarchy subscriber "hpolSub81"

===============================================================================

Scheduler Hierarchy - Subscriber hpolSub81

===============================================================================

Ingress Scheduler Policy:

Egress Scheduler Policy :

-------------------------------------------------------------------------------

Root (Ing)

|

No Active Members Found on slot 1

Root (Egr)

| slot(1)

|--(Q) : Sub=hpolSub81:hpolSlaProf1 2000->1/1/11:2000.1->8->Eth (Port 1/1/11)

|

|--(Q) : Sub=hpolSub81:hpolSlaProf1 2000->1/1/11:2000.1->7->Eth (Port 1/1/11)

|

|--(Q) : Sub=hpolSub81:hpolSlaProf1 2000->1/1/11:2000.1->6->Eth (Port 1/1/11)

|

|--(Q) : Sub=hpolSub81:hpolSlaProf1 2000->1/1/11:2000.1->5->Eth (Port 1/1/11)

|

|--(Q) : Sub=hpolSub81:hpolSlaProf1 2000->1/1/11:2000.1->4->Eth (Port 1/1/11)

|

|--(Q) : Sub=hpolSub81:hpolSlaProf1 2000->1/1/11:2000.1->3->Eth (Port 1/1/11)

|

|--(Q) : Sub=hpolSub81:hpolSlaProf1 2000->1/1/11:2000.1->2->Eth (Port 1/1/11)

|

|--(Q) : Sub=hpolSub81:hpolSlaProf1 2000->1/1/11:2000.1->1->Eth (Port 1/1/11)

|

Next Mile ATM

*A:Dut-C# show service active-subscribers ale-adjust subscriber "hpolSub321"

===============================================================================

Active Subscriber Access Loop Encapsulation adjustment

===============================================================================

Subscriber

SAP SLA profile

Data-link Offset(bytes)

-------------------------------------------------------------------------------

hpolSub321

5/1/1:100/1 hpolSlaProf1

atm +8

-------------------------------------------------------------------------------

No. of Access Loop Encapsulation adjustments: 1

===============================================================================

*A:Dut-C# show qos scheduler-hierarchy subscriber "hpolSub321"

===============================================================================

Scheduler Hierarchy - Subscriber hpolSub321

===============================================================================

Ingress Scheduler Policy:

Egress Scheduler Policy :

-------------------------------------------------------------------------------

Root (Ing)

|

No Active Members Found on slot 5

Root (Egr)

| slot(5)

|--(Q) : Sub=hpolSub321:hpolSlaProf1 2000->5/1/1:100/1->8:ATM (Port 5/1/1)

|

|--(Q) : Sub=hpolSub321:hpolSlaProf1 2000->5/1/1:100/1->7:ATM (Port 5/1/1)

|

|--(Q) : Sub=hpolSub321:hpolSlaProf1 2000->5/1/1:100/1->6:ATM (Port 5/1/1)

|

|--(Q) : Sub=hpolSub321:hpolSlaProf1 2000->5/1/1:100/1->5:ATM (Port 5/1/1)

|

|--(Q) : Sub=hpolSub321:hpolSlaProf1 2000->5/1/1:100/1->4:ATM (Port 5/1/1)

|

|--(Q) : Sub=hpolSub321:hpolSlaProf1 2000->5/1/1:100/1->3:ATM (Port 5/1/1)

|

|--(Q) : Sub=hpolSub321:hpolSlaProf1 2000->5/1/1:100/1->2:ATM (Port 5/1/1)

|

|--(Q) : Sub=hpolSub321:hpolSlaProf1 2000->5/1/1:100/1->1:ATM (Port 5/1/1)

|

===============================================================================

IP (Layer 3) Volume Accounting

Subscriber volume statistics by default count Layer 2 frame sizes optionally modified by configuration such as packet-byte-offset, last mile aware shaping, etc.

To report subscriber volume statistics as Layer 3 (IP) packet sizes, the volume-stats-type can be configured to ip in the subscriber profile:

volume-stats-type ip affects the subscriber statistics in SNMP, CLI, RADIUS accounting, XML accounting and Diameter Gx usage monitoring. Volume quota for RADIUS or Diameter Credit Control applications are interpreted as Layer 3 quota.

The following restrictions apply for volume-stats-type ip:

Separate IPv4 and IPv6 Counters

IPv4 and IPv6 forwarded and dropped subscriber traffic can be counted separately via a stat-mode v4-v6 command that is configured as a policer or queue qos override in the sla-profile. The stat-mode v4-v6 command is only applicable for Enhanced Subscriber Management (ESM).

For policers, the stat-mode command overrides the policer stat-mode configuration as defined in the sap-ingress or sap-egress qos policy. For details on sap-ingress and sap-egress policer stat-mode, refer to the Quality of Service Guide. For a policer in stat-mode v4-v6, following counters are available:

When a policer’s stat-mode is changed while the sla profile is in use, any previous counter values are lost and any new counters are set to zero.

For queues, a stat-mode is only available for use in Enhanced Subscriber Management (ESM) context to enable separate IPv4/IPv6 counters. For a queue in stat-mode v4-v6, following counters are available:

A queue’s stat-mode cannot be changed while the sla profile is in use.

Note that there will be no in-profile/out-of-profile forwarded and dropped counters for policers and queues in stat-mode v4-v6.

Non IP traffic (for example PPPoE LCP frames) is counted against the IPv4 counters.

The separate IPv4 and IPv6 forwarded and dropped counters are reported in

When a queue or policer is configured in stat-mode v4-v6, existing VSA’s are re-used in RADIUS detailed per queue / per policer accounting (configure subscriber-mgmt radius-accounting-policy <name> include-radius-attribute detailed-acct-attributes):

In addition the [26-6527-107] Alc-Acct-I-statmode / [26-6527-127] Alc-Acct-O-statmode is sent with value set to “v4-v6”.

Optionally a set of VSA's can be included in RADIUS accounting to report the aggregate IPv6 forwarded octets and packets of queues and policers with stat-mode v4-v6 enabled (configure subscriber-mgmt radius-accounting-policy <name> include-radius-attribute detailed-acct-attributes v6-aggregate-stats):

[26-6527-194] Alc-IPv6-Acct-Input-Packets

[26-6527-195] Alc-IPv6-Acct-Input-Octets

[26-6527-196] Alc-IPv6-Acct-Input-GigaWords

[26-6527-197] Alc-IPv6-Acct-Output-Packets

[26-6527-198] Alc-IPv6-Acct-Output-Octets

[26-6527-199] Alc-IPv6-Acct-Output-Gigawords

Refer to the 7750 SR RADIUS Attributes Reference Guide for a detailed description of all counter attributes.

The complete-subscriber-ingress-egress and custom-record-subscriber XML records use following fields to represent IPv4 and IPv6 forwarded/dropped octets and packets for queues or policers with stat-mode v4-v6 enabled:

v4po - IPv4PktsOffered (policer only)

v4oo - IPv4OctetsOffered (policer only)

v6po - IPv6PktsOffered (policer only)

v6oo - IPv6OctetsOffered (policer only)

v4pf - IPv4PktsForwarded

v6pf - IPv6PktsForwarded

v4pd - IPv4PktsDropped

v6pd - IPv4PktsDropped

v4of - IPv4OctetsForwarded

v6of - IPv6OctetsForwarded

v4od - IPv4OctetsDropped

v6od - IPv4OctetsDropped

For custom records, the following CLI is re-used to include v4/v6 counters if the queue is configured in stat-mode v4-v6:

i-counters

all-packets-offered-count # n/a

all-octets-offered-count # n/a

high-packets-offered-count # n/a

low-packets-offered-count # n/a

uncoloured-packets-offered-count # n/a

high-octets-offered-count # n/a

low-octets-offered-count # n/a

uncoloured-octets-offered-count # n/a

all-packets-offered-count # n/a

all-octets-offered-count # n/a

high-packets-discarded-count # IPv4

low-packets-discarded-count # IPv6

high-octets-discarded-count # IPv4

low-octets-discarded-count # IPv6

in-profile-packets-forwarded-count # IPv4

out-profile-packets-forwarded-count # IPv6

in-profile-octets-forwarded-count # IPv4

out-profile-octets-forwarded-count # IPv6

e-counters

in-profile-packets-forwarded-count # IPv4

in-profile-packets-discarded-count # IPv4

out-profile-packets-forwarded-count # IPv6

out-profile-packets-discarded-count # IPv6

in-profile-octets-forwarded-count # IPv4

in-profile-octets-discarded-count # IPv4

out-profile-octets-forwarded-count # IPv6

out-profile-octets-discarded-count # IPv6

On HSMDA, stat-mode v4-v6 is configured as a policer or queue qos override in the subscriber profile:

configure subscriber-mgmt

sub-profile "sub-profile-2" create

hsmda

egress-qos

qos 10

queue 1

stat-mode v4-v6

exit

exit

exit

ingress-qos

qos 10

policer 1

stat-mode v4-v6

exit

queue 1

stat-mode v4-v6

exit

exit

exit

exit

exit

The stat-mode on egress hsmda queues is always enabled per subscriber: when enabling stat-mode v4-v6 for one hsmda queue, it is automatically enabled for all hsmda queues for that subscriber profile.