Alcatel-Lucent 7950 SR User Configuration Manual page 284

MPLS Commands
Note that MPLS will keep the address list of flagged interfaces for a maximum of 60 seconds (not
user-configurable) from the time the first Resv message with the 'Preemption pending' flag is
received. This actually means that MPLS will request CSPF to find a path that excludes the flagged
interfaces in the first few retries until success or until 60 seconds have elapsed. Subsequent retries
after the 60 seconds will not exclude the flagged interfaces as it is assumed IGP has converged by
then and the Unreserved Bandwidth sub-TLV for that priority, or TE Class, in the TE database will
show the updated value taking into account the pre-empting LSP path reservation or a value of zero if
overbooked.
If the LSP has a configured secondary standby which is operationally UP, the 7x50 will switch the
path of the LSP to it and then start the MBB. If no standby path is available and a secondary non-
standby is configured, the 7x50 will start the MBB and signal the path of the secondary. The LSP
path will be switched to either the secondary or the new primary, whichever comes up first.
The no form of the command reverts the LSP path priority to the default values and results in setting
the setup priority to 7, in setting the holding priority to 0, and in clearing the 'soft preemption
desired' flag in the RRO in the Resv refresh message.
Default
no priority.
Parameters
setup-priority — The priority of the reservation for this session at setup time.
holding-priority — The priority of the reservation for this session at pre-emption action.
main-ct-retry-limit
Syntax main-ct-retry-limit number
no main-ct-retry-limit
Context
config>router>mpls>lsp
Description
This command configures the maximum number of retries the LSP primary path should be retried
with the LSP Diff-Serv main Class Type (CT).
When an unmapped LSP primary path goes into retry, it uses the main CT until the number of retries
reaches the value of the new main-ct-retry-limit parameter. If the path did not come up, it must start
using the backup CT at that point in time. By default, this parameter is set to infinite value. The new
main-ct-retry-limit parameter has no effect on an LSP primary path which retries due to a failure
event.
An unmapped LSP primary path is a path which has never received a Resv in response to the first
Path message sent. This can occur when performing a "shut/no-shut" on the LSP or LSP primary path
or when the node reboots. An unmapped LSP primary path goes into retry if the retry timer expired or
the head-end node received a PathErr message before the retry timer expired.
If the user entered a value of the main-ct-retry-limit parameter that is greater than the value of the
LSP retry-limit, the number of retries will still stop when the LSP primary path reaches the value of
the LSP retry-limit. In other words, the meaning of the LSP retry-limit parameter is not changed and
Page 284
Values
0 — 7 (0 is the highest priority and 7 is the lowest priority.)
Default
7 — This session does not pre-empt any other session.
Values
0 — 7 (0 is the highest priority and 7 is the lowest priority.)
Default
0 — This session does not get pre-empted by any other session.
7950 SR OS MPLS Configuration Guide