Recommended Settings For Routing Protocol Timers During Unified Issu - Juniper SERVICE AVAILABILITY - CONFIGURATION GUIDE V 11.1.X Configuration Manual

JUNOSe 11.1.x Service Availability Configuration Guide
Table 15: Behavior of Routing Protocols During a Unified In-Service Software Upgrade
You might want some or all traffic to be routed around the upgrading router rather
than accept a forwarding loss during the forwarding interruption. To do so, you must
configure your routing protocols appropriately. For example, you might raise the link
cost in IS-IS and OSPF, causing their neighbors to seek alternate routes that have
lower link costs. In PIM, you can set the priority for the router interface to zero to
ensure that the upgrading router is not selected as a designated router.
Related Topics

Recommended Settings for Routing Protocol Timers During Unified ISSU

You can use the default values for many of the routing protocol timers with no adverse
effect on a unified in-service software upgrade. For other timers, we recommend
particular values, as described in Table 16 on page 95.
94
Recommended Settings for Routing Protocol Timers During Unified ISSU
(continued)
Protocol Behavior
OSPF OSPF timers are not negotiable between peers. Unified ISSU generates a
warning if the hello timers or the keepalive timers are not long enough to
survive the forwarding plane upgrade.
OSPF begins a graceful restart before the SRP module switchover. When
you configure graceful restart before the unified in-service software
upgrade, you must ensure that the graceful restart times are long enough
to allow recovery.
OSPF sends out hello messages and keepalive messages immediately
before and immediately after forwarding plane restart, independent of the
interval since it last sent them.
PIM If necessary, temporarily lengthens the hold times in hello messages. PIM
guarantees that at least one hello message with a lengthened hold time is
sent to each neighbor.
If necessary, increases the join-prune hold time. PIM guarantees that at
least one join-prune message with a lengthened hold time is sent to each
neighbor.
RIP RIP timers do not affect unified ISSU.
RSVP-TE If necessary, temporarily lengthens the graceful restart timers to survive
the SRP module switchover.
If necessary, lengthens the hello timers to survive the forwarding plane
upgrade.
Application Support for Unified ISSU on page 71