This feature enhances procedures of the timer and manual resignal (both delay and lsp options) of a RSVP-TE bypass LSP path by updating the administrative group information of the current path links and checking for administrative group constraints. The following sequence describes the timer and manual resignal enhancements.
CSPF updates the administrative group membership of the current bypass LSP path and checks if the path violates the administrative group constraints of the first primary path which was associated with this bypass LSP. This is referred to as the initial PSB.
CSPF attempts a new path computation for the bypass LSP using the PLR constraints of the initial PSB.
MPLS uses the information returned by CSPF and determines if the new bypass path is more optimal.
If CSPF indicated the updated administrative group information of current path violated the administrative group constraint of the initial PSB, then the new path is more optimal.
Otherwise, the new path is more optimal only if its metric is lower than the updated metric of the current bypass path.
If the path returned by CSPF is found to be a more optimal bypass path then the following sequence of actions is performed.
MPLS signals and programs the new path.
Because the administrative group constraint is not part of the PLR definition, MPLS evaluates the PSBs of all PLRs associated with the current bypass, and takes the following actions.
MPLS moves to the new bypass path the PSB associations in which the administrative group constraints are not violated by the new bypass path.
Among the remaining PSBs, MPLS keeps with the current bypass path the PSB associations in which the administrative group constraints are not violated by the updated administrative group information of the current bypass path.
These PSBs are re-evaluated at the next timer or manual resignal MBB following the same procedure, as described in RSVP-TE Bypass LSP Path Administrative Group Information Update in Manual and Timer Resignal MBB.
Among the remaining PSBs, MPLS detaches from current bypass path the PSB associations in which the administrative group constraints are violated by the updated administrative group information of the current bypass path.
These orphaned PSBs are re-evaluated by the FRR background task, which checks unprotected PSBs on a regular basis and following the same procedure, as described in RSVP-TE Bypass LSP Path Administrative Group Information Update in Manual and Timer Resignal MBB.
If the path returned by CSPF is found to be less optimal than the current bypass path or if CSPF did not return a new path, the following actions are performed.
If the updated administrative group information of the current bypass path did not change, MPLS keeps the current bypass path and all PSB associations.
If the updated administrative group information of the current bypass path has changed, MPLS evaluates the PSBs of all PLRs associated with the current bypass, and performs the following actions.
MPLS keeps with the current bypass path the PSB associations in which the administrative group constraints are not violated by the updated administrative group information of the current bypass path.
MPLS detaches from current bypass path the PSB associations in which the administrative group constraints are violated by the updated administrative group information of the current bypass path.
These orphaned PSBs are re-evaluated by the FRR background task, which checks unprotected PSBs on a regular basis and following the same procedure, as described in RSVP-TE Bypass LSP Path Administrative Group Information Update in Manual and Timer Resignal MBB.