[no] primary path-name
config>router>mpls>lsp
This command specifies a preferred path for the LSP. This command is optional only if the secondary path-name is included in the LSP definition. Only one primary path can be defined for an LSP.
Some of the attributes of the LSP, such as the bandwidth and hop limit, can be optionally specified as the attributes of the primary path. The attributes specified in the primary path-name command override the comparable LSP attributes that are defined in the config>router>mpls>lsp context.
The no form of this command deletes the association of this path-name from the lsp lsp-name. All configurations specific to this primary path, such as record, bandwidth, and hop limit, are deleted. The primary path must be shut down first in order to delete it. The no primary command will not result in any action except a warning message on the console indicating that the primary path is administratively up.
n/a
specifies the case-sensitive alphanumeric name label for the LSP path, up to 32 characters in length
[no] secondary path-name
config>router>mpls>lsp
This command specifies an alternative path that the LSP uses if the primary path is not available. This command is optional and is not required if the config>router>mpls>lsp lsp-name> primary path-name command is specified. After the switchover from the primary path to the secondary path, the 7705 SAR software continuously tries to revert to the primary path. The switch back to the primary path is based on the retry-timer interval.
Up to two secondary paths can be specified. Both secondary paths are considered equal, and the first available path is used. The 7705 SAR software will not switch back between secondary paths.
The 7705 SAR software starts signaling all non-standby secondary paths at the same time. Retry counters are maintained for each unsuccessful attempt. Once the retry limit is reached on a path, software will not attempt to signal the path and administratively shuts down the path. The first successfully established path is made the active path for the LSP.
The no form of this command removes the association between this path-name and lsp-name. All specific configurations for this association are deleted. The secondary path must be shut down first in order to delete it. The no secondary path-name command will not result in any action except a warning message on the console indicating that the secondary path is administratively up.
n/a
specifies the case-sensitive alphanumeric name label for the LSP path, up to 32 characters in length
[no] adaptive
config>router>mpls>lsp>primary
config>router>mpls>lsp>secondary
This command enables the make-before-break (MBB) functionality for an LSP or a primary or secondary LSP path. When enabled for the LSP, a make-before-break operation will be performed for the primary path and all the secondary paths of the LSP.
adaptive
bandwidth rate-in-mbps
no bandwidth
config>router>mpls>lsp>primary
config>router>mpls>lsp>secondary
This command specifies the amount of bandwidth to be reserved for the LSP path.
The no form of this command resets bandwidth parameters (no bandwidth is reserved).
no bandwidth — bandwidth setting in the global LSP configuration
specifies the amount of bandwidth reserved for the LSP path in Mb/s
hop-limit number
no hop-limit
config>router>mpls>lsp>primary
config>router>mpls>lsp>secondary
This optional command overrides the config>router>mpls>lsp lsp-name>hop-limit command. This command specifies the total number of hops that an LSP traverses, including the ingress and egress routers.
This value can be changed dynamically for an LSP that is already set up with the following implications:
If the new value is less than the current number of hops of the established LSP, then the LSP is brought down. MPLS then tries to re-establish the LSP within the new hop-limit number. If the new value is equal to or greater than the current hops of the established LSP, then the LSP will be unaffected.
The no form of this command resets the hop limit to the value defined under the LSP definition using the config>router>mpls>lsp lsp-name>hop-limit command.
no hop-limit
specifies the number of hops the LSP can traverse, expressed as an integer
path-preference preference-number
no path-preference
config>router>mpls>lsp>secondary
This command allows a priority value to be assigned to a standby secondary LSP path. The secondary LSP path must be configured in standby mode using the standby command to ensure that it is signaled and maintained indefinitely in a hot-standby state. The standby secondary LSP path configured with the highest priority (the lowest path-preference value) is made the active LSP when the primary LSP is not in use. If multiple standby secondary LSP paths are configured wit the same value, the system selects the path with the lowest uptime.
If all standby secondary paths have the default path-preference value, a non-standby secondary path remains the active path even though a configured standby secondary path is available.
This command only applies to secondary LSP paths that have been configured in standby mode.
The no form of the command resets the path-preference value to its default.
255
specifies a priority value for a standby secondary LSP path; the lower the value, the higher the priority.
[no] record
config>router>mpls>lsp>primary
config>router>mpls>lsp>secondary
This command enables recording of all the hops that an LSP path traverses. Enabling record increases the size of the PATH and RESV refresh messages for the LSP, since this information is carried end-to-end along the path of the LSP. The increase in control traffic per LSP may impact scalability.
The no form of this command disables the recording of all the hops for the given LSP. There are no restrictions as to when the no command can be used. The no form of this command also disables the record-label command.
record
[no] record-label
config>router>mpls>lsp>primary
config>router>mpls>lsp>secondary
This command enables recording of all the labels at each node that an LSP path traverses. Enabling the record-label command will also enable the record command, if it is not already enabled.
The no form of this command disables the recording of the hops that an LSP path traverses.
record-label
[no] srlg
config>router>mpls>lsp>secondary
This command enables the use of the SRLG constraint in the CSPF computation of a secondary path for an RSVP-TE LSP at the head-end LER. When this feature is enabled, CSPF includes the SRLG constraint in the computation of the secondary RSVP-TE LSP path.
CSPF requires that the primary LSP be established already and in the up state, since the head-end LER needs the most current ERO computed by CSPF for the primary path and CSPF includes the list of SRLGs in the ERO during the CSPF computation of the primary path. At a subsequent establishment of a secondary path with the SRLG constraint, the MPLS/RSVP-TE task queries CSPF again, which provides the list of SRLG numbers to be avoided. CSPF prunes all links with interfaces that belong to the same SRLGs as the interfaces included in the ERO of the primary path. If CSPF finds a path, the secondary path is set up. If CSPF does not find a path, MPLS/RSVP-TE keeps retrying the requests to CSPF.
If CSPF is not enabled on the LSP (using the lsp lsp-name>cspf command), a secondary path of that LSP that includes the SRLG constraint is shut down and a specific failure code indicates the exact reason for the failure in the show>router>mpls>lsp>path> detail output.
At initial primary LSP path establishment, if the primary path does not come up or is not configured, the SRLG secondary path is not signaled and is put in the down state. A specific failure code indicates the exact reason for the failure in the show>router>mpls>lsp>path> detail output. However, if a non-SRLG secondary path was configured, such as a secondary path with the SRLG option disabled, MPLS/RSVP-TE task signals it and the LSP uses it.
As soon as the primary path is configured and successfully established, MPLS/RSVP-TE moves the LSP to the primary path and signals all SRLG secondary paths.
Any time the primary path is reoptimized, has undergone a make-before-break (MBB) operation, or has come back up after being down, the MPLS/RSVP-TE task checks with CSPF to determine if the SRLG secondary path should be resignaled. If the MPLS/RSVP-TE task finds that the current secondary path is no longer SRLG disjoint — for example, the path became ineligible — it puts the path on a delayed make-before-break immediately after the expiry of the retry timer. If MBB fails on the first try, the secondary path is torn down and the path is put on retry.
At the next opportunity (that is, when the primary path goes down), the LSP uses of an eligible SRLG secondary path if the secondary path is in the up state. If all secondary eligible SRLG paths are in the down state, MPLS/RSVP-TE uses a non-SRLG secondary path if the path is configured and in the up state. If, while the LSP is using a non-SRLG secondary path, an eligible SRLG secondary path comes back up, MPLS/RSVP-TE will not switch the path of the LSP to it. As soon as the primary path is resignaled and comes up with a new SRLG list, MPLS/RSVP-TE resignals the secondary path using the new SRLG list.
A secondary path that becomes ineligible as a result of an update to the SRLG membership list of the primary path will have its ineligibility status removed when any of the following events occurs:
A successful MBB operation of the standby SRLG path occurs, making it eligible again.
The standby path goes down, in which case MPLS/RSVP-TE puts the standby on retry when the retry timer expires. If successful, it becomes eligible. If not successful after the retry timer expires or the number of retries reaches the configured retry-limit value, it is left down.
The primary path goes down, in which case the ineligible secondary path is immediately torn down and will only be resignaled when the primary path comes back up with a new SRLG list.
Once the primary path of the LSP is set up and is operationally up, any subsequent changes to the SRLG membership of an interface that the primary path is using is not considered until the next opportunity that the primary path is resignaled. The primary path may be resignaled due to a failure or to a make-before-break operation. A make-before-break operation occurs as a result of a global revertive operation, a timer-based or manual reoptimization of the LSP path, or a change by the user to any of the path constraints.
Once an SRLG secondary path is set up and is operationally up, any subsequent changes to the SRLG membership of an interface that the secondary path is using is not considered until the next opportunity that the secondary path is resignaled. The secondary path is resignaled due to a failure, to a resignaling of the primary path, or to a make-before-break operation. A make-before-break operation occurs as a result of a timer-based or manual reoptimization of the secondary path, or a change by the user to any of the path constraints of the secondary path, including enabling or disabling the SRLG constraint itself.
In addition, any user-configured include or exclude admin group statements for this secondary path are checked along with the SRLG constraints by CSPF.
The no form of the command reverts to the default value.
no srlg
[no] standby
config>router>mpls>lsp>secondary
The secondary path LSP is normally signaled if the primary path LSP fails. The standby keyword ensures that the standby secondary path LSP is signaled and maintained indefinitely in a hot-standby state. When the primary path is re-established, the traffic is switched back to the primary path LSP.
The no form of this command specifies that the secondary LSP is signaled when the primary path LSP fails.
n/a