The following fields describe RFC 1583 compatibility, OSPF timers,
and graceful restart:
OSPF – Advanced Settings
Description
RFC 1583 Compatibility
Select to ensure compatibility with RFC
1583 (OSPF Version 2).
Timers
SPF Calculation Delay
(sec)—Allows you to tune the delay time between receiving
new topology information and performing an SPF calculation. Lower
values enable faster OSPF re-convergence. Routers peering with the
firewall should be tuned in a similar manner to optimize convergence
times.
LSA Interval (sec)—Specifies the minimum
time between transmissions of two instances of the same LSA (same router,
same type, same LSA ID). This is equivalent to MinLSInterval in
RFC 2328. Lower values can be used to reduce re-convergence times
when topology changes occur.
Graceful Restart
Enable Graceful Restart—Enabled
by default, a firewall enabled for this feature will instruct neighboring
routers to continue using a route through the firewall while a transition
takes place that renders the firewall temporarily down.
Enable Helper Mode—Enabled by default,
a firewall enabled for this mode continues to forward to an adjacent device
when that device is restarting.
Enable Strict LSA Checking—Enabled
by default, this feature causes an OSPF helper mode enabled firewall
to exit helper mode if a topology change occurs.
Grace Period (sec)—Period of time,
in seconds, that peer devices should continue to forward to this
firewall while adjacencies are being re-established or the router
is being restarted (range is 5-1,800; default is 120).
Max Neighbor Restart Time—Maximum
grace period, in seconds, that the firewall will accept as a help-mode
router. If the peer devices offers a longer grace period in its
grace LSA, the firewall will not enter helper mode (range is 5-1,800;
default is 140).
