Alcatel-Lucent 6850 Switch User Manual


 
Configuring IS-IS Configuring IS-IS
OmniSwitch 6800/6850/9000 Advanced Routing Configuration Guide December 2007 page 3-31
Configuring Redundant Switches in a Stack for Graceful Restart
By default, IS-IS graceful restart is disabled. When graceful restart is enabled, the router can either be a
helper or a restarting router. When graceful restart is enabled on the router, the helper mode is automati-
cally enabled by default. To configure IS-IS graceful restart support on OmniSwitch 6850 Series switches,
use the ip isis graceful-restart command.
Note. In the current release, only the graceful restart helper mode is supported.
For example, to configure graceful restart on the router, enter:
-> ip isis graceful-restart
The helper mode can be disabled on the router with the ip isis graceful-restart helper command. For
example, to disable the helper support for neighboring routers, enter the following:
-> ip isis graceful-restart helper disable
To disable support for graceful restart, use the no form of the ip isis graceful-restart command by enter-
ing:
-> no ip isis graceful-restart
On OmniSwitch 6850 Series switches, continuous forwarding during a graceful restart depends on several
factors. If the secondary module has a different router MAC than the primary module, or if one or more
ports of a VLAN belonged to the primary module, spanning tree re-convergence might disrupt forwarding
state, even though IS-IS performs a graceful restart.
Note. Graceful restart is only supported on active ports (i.e., interfaces), which are on the secondary or
idle switches in a stack during a takeover. It is not supported on ports on a primary switch in a stack.