VPLS STP commands

stp

Syntax

stp

Context

config>service>vpls

config>service>vpls>sap

Platforms

Supported on all 7210 SAS platforms as described in this document, including those operating in access-uplink mode

Description

Commands in this context configure the Spanning Tree Protocol (STP) parameters.

The Nokia STP has a few modifications to better suit the operational characteristics of VPLS services. The most evident change is to the root bridge election. Since the core network operating between the Nokia service routers should not be blocked, the root path is calculated from the core perspective.

auto-edge

Syntax

auto-edge

no auto-edge

Context

config>service>vpls>sap>stp

config>service>vpls>spoke-sdp>stp (not supported in access-uplink operating mode)

Platforms

Supported on all 7210 SAS platforms as described in this document, including those operating in access-uplink mode

Description

This command configures automatic detection of the edge port characteristics of the SAP or spoke-SDP.

The no form of this command reverts to the default value.

Default

auto-edge

edge-port

Syntax

[no] edge-port

Context

config>service>vpls>sap>stp

config>service>vpls>spoke-sdp>stp

Platforms

Supported on all 7210 SAS platforms as described in this document, including those operating in access-uplink mode

Description

Note:

The config>service>vpls>spoke-sdp>stp context is not supported on platforms configured in the access-uplink operating mode.

This command configures the SAP or SDP as an edge or non-edge port. If auto-edge is enabled for the SAP, this value is used only as the initial value.

RSTP, however, can detect that the actual situation is different from what edge-port may indicate.

Initially, the value of the SAP or spoke-SDP parameter is set to edge-port. This value changes if:

  • A BPDU is received on that port. This means that after all there is another bridge connected to this port. Then the edge-port becomes disabled.

  • If auto-edge is configured and no BPDU is received within a certain period of time, RSTP concludes that it is on an edge and enables the edge-port.

The no form of this command reverts to the default value.

Default

no edge-port

forward-delay

Syntax

forward-delay seconds

no forward-delay

Context

config>service>vpls>stp

config>service>vpls>spoke-sdp>stp

Platforms

Supported on all 7210 SAS platforms as described in this document, including those operating in access-uplink mode

Description

Note:

The config>service>vpls>spoke-sdp>stp context is not supported on platforms configured in the access-uplink operating mode.

RSTP, as defined in the IEEE 802.1D-2004 standards, transition to the forwarding state via a handshaking mechanism (rapid transition), without any waiting times. If handshaking fails (e.g. on shared links), the system falls back to the timer-based mechanism defined in the original STP (802.1D-1998) standard.

A shared link is a link with more than two nodes (for example, a shared 10/100BaseT segment). The port-type command is used to configure a link as point-to-point or shared.

For timer-based transitions, the 802.1D-2004 standard defines an internal variable forward-delay, which is used in calculating the default number of seconds that a SAP spends in the discarding and learning states when transitioning to the forwarding state.

The value of the forward-delay variable depends on the STP operating mode of the VPLS instance:

  • in rstp or mstp mode, but only when the SAP has not fallen back to legacy STP operation, the value configured by the hello-time command is used;

  • in all other situations, the value configured by the forward-delay command is used.

Default

15 seconds

Parameters

seconds

Specifies the forward delay timer for the STP instance in seconds.

Values

4 to 30

hello-time

Syntax

hello-time hello-time

no hello-time

Context

config>service>vpls>stp

config>service>vpls>spoke-sdp>stp

Platforms

Supported on all 7210 SAS platforms as described in this document, including those operating in access-uplink mode

Description

Note:

The config>service>vpls>spoke-sdp>stp context is not supported on platforms configured in the access-uplink operating mode.

This command configures the STP hello time for the Virtual Private LAN Service (VPLS) STP instance.

The hello time parameter defines the default timer value that controls the sending interval between BPDU configuration messages by this bridge, on ports where this bridge assumes the designated role.

The active hello time for the spanning tree is determined by the root bridge (except when the STP is running in RSTP mode, then the hello time is always taken from the locally configured parameter).

The configured hello-time can also be used to calculate the forward delay. See auto-edge.

The no form of this command reverts to the default value.

Default

2

Parameters

hello-time

Specifies the hello time for the STP instance in seconds.

Values

1 to 10

hold-count

Syntax

hold-count BDPU tx hold count

no hold-count

Context

config>service>vpls>stp

config>service>vpls>spoke-sdp>stp (not supported in access-uplink operating mode)

Platforms

Supported on all 7210 SAS platforms as described in this document, including those operating in access-uplink mode

Description

This command configures the peak number of BPDUs that can be transmitted in a period of one second.

The no form of this command reverts to the default value.

Default

6

Parameters

BDPU tx hold count

Specifies the hold count for the STP instance in seconds.

Values

1 to 10

link-type

Syntax

link-type {pt-pt | shared}

no link-type

Context

config>service>vpls>sap>stp

config>service>vpls>spoke-sdp>stp (not supported in access-uplink operating mode)

Platforms

Supported on all 7210 SAS platforms as described in this document, including those operating in access-uplink mode

Description

This command instructs STP on the maximum number of bridges behind this SAP. If there is only a single bridge, transitioning to forwarding state is based on handshaking (fast transitions). If more than two bridges are connected via a shared media, their SAP should all be configured as shared, and timer-based transitions are used.

The no form of this command reverts the default value.

Default

pt-pt

mst-instance

Syntax

mst-instance mst-inst-number

Context

config>service>vpls>sap>stp

Platforms

Supported on all 7210 SAS platforms as described in this document, including those operating in access-uplink mode

Description

This command configures MSTI related parameters at SAP level. This context can be open only for existing mst-instances defined at the service level.

Parameters

mst-inst-number

Specifies an existing MSTI number.

Values

1 to 4094

mst-path-cost

Syntax

mst-path-cost inst-path-cost

no mst-path-cost

Context

config>service>vpls>sap>stp>mst-instance

Platforms

Supported on all 7210 SAS platforms as described in this document, including those operating in access-uplink mode

Description

This commands specifies path-cost within a specific instance. If a loop occurs, this parameter indicates the probability of a specific port being assigned a forwarding state. (The highest value expresses lowest priority).

The no form of this command reverts to the default value.

Default

The path-cost is proportional to link speed.

Parameters

inst-path-cost

Specifies the contribution of this port to the MSTI path cost.

Values

1 to 200000000

mst-port-priority

Syntax

mst-port-priority stp-priority

no mst-port-priority

Context

config>service>vpls>sap>stp>mst-instance

Platforms

Supported on all 7210 SAS platforms as described in this document, including those operating in access-uplink mode

Description

This commands specifies the port priority within a specific instance. If a loop occurs, this parameter indicates the probability of a specific port being assigned a forwarding state.

The no form of this command reverts to the default value.

Default

128

Parameters

stp-priority

Specifies the value of the port priority field.

max-age

Syntax

max-age seconds

no max-age

Context

config>service>vpls>stp

Platforms

Supported on all 7210 SAS platforms as described in this document, including those operating in access-uplink mode

Description

This command indicates how many hops a BPDU can traverse the network starting from the root bridge. The message age field in a BPDU transmitted by the root bridge is initialized to 0. Each other bridge takes the message_age value from BPDUs received on their root port and increment this value by 1. The message_age therefore reflects the distance from the root bridge. BPDUs with a message age exceeding max-age are ignored.

STP uses the max-age value configured in the root bridge. This value is propagated to the other bridges via the BPDUs.

The no form of this command reverts to the default value.

Default

20

Parameters

seconds

Specifies the max info age for the STP instance in seconds. Allowed values are integers in the range 6 to 40.

mode

Syntax

mode {rstp | comp-dot1w | dot1w | mstp | pmstp}

no mode

Context

config>service>vpls>stp

Platforms

Supported on all 7210 SAS platforms as described in this document, including those operating in access-uplink mode

Description

This command specifies the version of STP the bridge is currently running.

See Spanning tree operating modes for more information about these modes.

The no form of this command reverts the STP variant to the default value.

Default

rstp

Parameters

rstp

Corresponds to the Rapid Spanning Tree Protocol specified in IEEE 802.1D/D4-2003.

dot1w

Corresponds to the mode where the Rapid Spanning Tree is backward compatible with IEEE 802.1w.

compdot1w

Corresponds to the Rapid Spanning Tree Protocol fully conformant to IEEE 802.1w.

mstp

Sets MSTP as the STP mode of operation. Corresponds to the Multiple Spanning Tree Protocol specified in 802.1Q REV/D5.0-09/2005

pmstp

Specifies the PMSTP mode, which is only supported in VPLS services where the mVPLS flag is configured.

mst-instance

Syntax

[no] mst-instance mst-inst-number

Context

config>service>vpls>stp

Platforms

Supported on all 7210 SAS platforms as described in this document, including those operating in access-uplink mode

Description

This command configures Multiple Spanning Tree Instance (MSTI) related parameters. MSTP supports 16 instances. The instance 0 is mandatory (by protocol) and cannot be created by the CLI. The software automatically maintains this instance.

Parameters

mst-inst-number

Specifies the MST instance.

Values

1 to 4094

mst-priority

Syntax

mst-priority bridge-priority

no mst-priority

Context

config>service>vpls>stp>mst-instance

Platforms

Supported on all 7210 SAS platforms as described in this document, including those operating in access-uplink mode

Description

This command specifies the bridge priority for this specific Multiple Spanning Tree Instance for this service. The bridge-priority value reflects likelihood that the switch is chosen as the regional root switch (65535 represents the least likely). It is used as the highest 4 bits of the Bridge ID included in the MSTP BPDU's generated by this bridge.

The values of the priority are only multiples of 4096 (4k). If a value is specified that is not a multiple of 4K, the value is replaced by the closest multiple of 4K (lower than the value entered).

The no form of this command reverts to the default value.

Default

32768 — All instances that are created by the vlan-range command do not have explicit definition of bridge-priority and inherits the default value.

Parameters

bridge-priority

Specifies the priority of this specific Multiple Spanning Tree Instance for this service.

Values

0 to 65535

vlan-range

Syntax

[no] vlan-range [vlan-range]

Context

config>service>vpls>stp>mst-instance

Platforms

Supported on all 7210 SAS platforms as described in this document, including those operating in access-uplink mode

Description

This command specifies a range of VLANs associated with a certain MST-instance. This range applies to all SAPs of the mVPLS.

Every VLAN range that is not assigned within any of the created mst-instance is automatically assigned to mst-instance 0. This instance is automatically maintained by the software and cannot be modified. Changing the VLAN range value can be performed only when the specific mst-instance is shutdown.

The no form of this command removes the vlan-range from a specific mst-instance.

Parameters

vlan-range

The first VLAN range specifies the left-bound (that is, minimum value) of a range of VLANs that are associated with the mVPLS SAP. This value must be smaller than (or equal to) the second VLAN range value. The second VLAN range specifies the right-bound (that is, maximum value) of a range of VLANs that are associated with the mVPLS SAP.

Values

1 to 4094

mst-max-hops

Syntax

mst-max-hops hops-count

no mst-max-hops

Context

config>service>vpls>stp

Platforms

Supported on all 7210 SAS platforms as described in this document, including those operating in access-uplink mode

Description

This command specifies the number of hops in the region before BPDU is discarded and the information held for the port is aged out. The root bridge of the instance sends a BPDU (or M-record) with remaining-hop-count set to configured max-hops. When a bridge receives the BPDU (or M-record), it decrements the received remaining-hop-count by 1 and propagates it in BPDU (or M-record) it generates.

The no form of this command reverts to the default value.

Default

20

Parameters

hops-count

Specifies the maximum number of hops.

Values

1 to 40

mst-name

Syntax

mst-name region-name

no mst-name

Context

config>service>vpls>stp

Platforms

Supported on all 7210 SAS platforms as described in this document, including those operating in access-uplink mode

Description

This command defines an MST region name. Two bridges are considered part of the same MST region when their configuration of the MST region name, the MST-revision and VLAN-to-instance assignment, is identical.

The no form of this command removes region-name from the configuration.

Default

no mst-name

Parameters

region-name

Specifies an MST-region name up to 32 characters.

mst-revision

Syntax

mst-revision revision-number

Context

config>service>vpls>stp

Platforms

Supported on all 7210 SAS platforms as described in this document, including those operating in access-uplink mode

Description

This command defines the MST configuration revision number. Two bridges are considered as a part of the same MST region if their configured MST-region name, MST-revision, and VLAN-to-instance are identical.

The no form of this command reverts to the default value.

Default

0

Parameters

revision-number

Specifies the MSTP region revision number to define the MSTP region.

Values

0 to 65535

path-cost

Syntax

path-cost sap-path-cost

no path-cost

Context

config>service>vpls>sap>stp

config>service>vpls>spoke-sdp>stp (not supported in access-uplink operating mode)

Platforms

Supported on all 7210 SAS platforms as described in this document, including those operating in access-uplink mode

Description

This command configures the STP path cost for the SAP or spoke-SDP.

The path cost is used by STP to calculate the path cost to the root bridge. The path cost in BPDUs received on the root port is incremented with the configured path cost for that SAP. When BPDUs are sent out other egress SAPs or spoke-SDPs, the newly calculated root path cost is used.

STP suggests that the path cost is defined as a function of the link bandwidth. Since SAPs are controlled by complex queuing dynamics, in the 7210 SAS the STP path cost is a purely static configuration.

The no form of this command reverts to the default value.

Parameters

path-cost

Specifies the path cost for the SAP or spoke-SDP.

Values

1 to 200000000 (1 is the lowest cost)

Default

10

port-num

Syntax

[no] port-num virtual-port-number

Context

config>service>vpls>sap>stp

config>service>vpls>spoke-sdp>stp (not supported in access-uplink operating mode)

Platforms

Supported on all 7210 SAS platforms as described in this document, including those operating in access-uplink mode

Description

This command configures the virtual port number which uniquely identifies a SAP within configuration bridge protocol data units (BPDUs). The internal representation of a SAP is unique to a system and has a reference space much bigger than the 12 bits definable in a configuration BPDU. STP takes the internal representation value of a SAP and identifies it with it’s own virtual port number that is unique to every other SAP defined on the TLS. The virtual port number is assigned at the time that the SAP is added to the TLS. Since the order that the SAP was added to the TLS is not preserved between reboots of the system, the virtual port number may change between restarts of the STP instance.

The virtual port number cannot be administratively modified.

priority

Syntax

priority bridge-priority

no priority

Context

config>service>vpls>stp

Platforms

Supported on all 7210 SAS platforms as described in this document, including those operating in access-uplink mode

Description

The bridge-priority command is used to populate the priority portion of the bridge ID field within outbound BPDUs (the most significant 4 bits of the bridge ID). It is also used as part of the decision process when determining the best BPDU between messages received and sent. All values are truncated to multiples of 4096, conforming with IEEE 802.1t and 802.1D-2004.

The no form of this command reverts to the default value.

Default

4096

Parameters

bridge-priority

Specifies the bridge priority for the STP instance.

Values

Allowed values are integers in the range of 4096 to 65535 with 4096 being the highest priority. The actual bridge priority value stored/used is the number entered with the lowest 12 bits masked off, which means the actual range of values is 4096 to 61440 in increments of 4096.

priority

Syntax

priority stp-priority

no priority

Context

config>service>vpls>spoke-sdp (not supported in access-uplink operating mode)

config>service>vpls>sap>stp

Platforms

Supported on all 7210 SAS platforms as described in this document, including those operating in access-uplink mode

Description

This command configures the Nokia STP priority for the SAP or spoke-SDP.

STP priority is a configurable parameter associated with a SAP or spoke-SDP. When configuration BPDUs are received, the priority is used in some circumstances as a tie breaking mechanism to determine whether the SAP or spoke-SDP is designated or blocked.

In traditional STP implementations (802.1D-1998), this field is called the port priority and has a value of 0 to 255. This field is coupled with the port number (0 to 255 also) to create a 16 bit value. In the latest STP standard (802.1D-2004) only the upper 4 bits of the port priority field are used to encode the SAP or spoke-SDP priority. The remaining 4 bits are used to extend the port ID field into a 12 bit virtual port number field. The virtual port number uniquely references a SAP within the STP instance.

STP computes the actual priority by taking the input value and masking out the lower four bits.The result is the value that is stored in the priority parameter. For instance, if a value of 0 is entered, masking out the lower 4 bits results in a parameter value of 0. If a value of 255 is entered, the result is 240.

The no form of this command reverts to the default value.

Default

128

Parameters

stp-priority

Specifies the STP priority value for the SAP. Allowed values are integers in the range of 0 to 255, 0 being the highest priority. The actual value used for STP priority (and stored in the configuration) is the result of masking out the lower 4 bits, therefore the actual value range is 0 to 240 in increments of 16.