Brocade Network Advisor SAN + IP User Manual v12.1.0 - Manual (Page 1386)

Brocade Network Advisor SAN + IP User Manual 1337
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LSP
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- Path Select Mode - The choices are Manual and Unconditional. If Manual is chosen, traffic
is shifted to an alternate path only if the selected path fails. If the path recovers, traffic is
shifted back. If Unconditional is chosen, the traffic stays on the selected path even if the
path fails. If you do not want to specify a path select mode or want to remove the
configured path select mode, select None.
• Primary - Selected by default.
• Secondary - Activated if a Path Selection Mode other than None is selected. To define
a secondary path, enter the secondary path name in the Secondary field.
- Record Routes - Select this checkbox to record LSP path information so that it can be
displayed.
- Reoptimize Timer - The re-optimize timer is a periodic timer for triggering the activation of
all pending LSP configuration changes.
- Revert Timer - The revert timer allows a period of time to elapse after a failback to a
primary path. This allows some time for conditions on a path to stabilize and prevents
unnecessary repetitive failover/failbacks that might occur if a path goes up and down
frequently.
- Setup Priority - The setup priority is used in concert with Hold Priority to determine priority
for an LSP at the ingress LER. The setup priority determines priority when several LSPs are
enabled at the same time, as is the case at start-up or after a re-boot. The setup priority is
also used in concert with the Mean Rate to determine if there is enough reservable
bandwidth available on an interface to allow the LSP to be activated.
- Hold Priority - The hold priority can be used to prevent an operating LSP from giving up
resources to an LSP with a higher setup priority. Both the setup and hold priorities allow
values from 0 to 7, with 0 as the highest priority and 7 as the lowest. To be useful, the hold
priority needs to equal to or less than the setup priority. For example, assume you have two
LSPs with a setup priority of 2 and a hold priority of 1. If either LSP should be interrupted
by a re-boot, the hold priority would prevent shifting of resources because the setup
priority is lower. The hold priority is also used in concert with the Mean Rate to allocate
reservable bandwidth to an LSP.
- Traffic Engineering - The following settings determine the bandwidth requirements for an
LSP:
• Mean Rate - Sets the average data rate supported. Mean Rate is used in concert with
Hold Priority in allocating reservable bandwidth for an LSP. As LSPs are activated,
bandwidth is allocated to meet their mean rate requirements. As bandwidth is
allocated, the amount of reservable bandwidth available is correspondingly reduced.
The LSP’s hold priority is used to conserve the use of the remaining bandwidth.
available bandwidth is adjusted downward for lower priority LSPs to ensure that
bandwidth remains available higher priority LSPs. If the mean rate for a given priority
becomes higher than the bandwidth available for that priority, that LSP is preempted
and the bandwidth is made available to LSPs with a higher hold priority.
Mean Rate is also used with Setup Priority in determining if there is enough
reservable bandwidth available to allow an LSP to be activated. In this case as
bandwidth is allocated and the amount of reservable bandwidth available is
correspondingly reduced, there may not be enough bandwidth available to meet the
mean rate requirements for an LSP with a low setup priority.