Cisco 6500 - Catalyst Series 10 Gigabit EN Interface Module Expansion, Configuration Manual, Page: 161 / 742

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Catalyst 6500 Series Switch and Cisco 7600 Series Router Firewall Services Module Configuration Guide using ASDM
OL-20748-01
Chapter 8 Configuring IP Routing and DHCP Services
Configuring OSPF
The spf-holdtime is the minimum time (in seconds) between two consecutive SPF calculations. It can be
an integer from 0 to 65535. The default time is 10 seconds. A value of 0 means that there is no delay;
that is, two SPF calculations can be done, one immediately after the other.
The following example shows how to configure route calculation timers:
hostname(config)# router ospf 1
hostname(config-router)#
timers spf 10 120
Logging Neighbors Going Up or Down
By default, the system sends a system log message when an OSPF neighbor goes up or down.
Configure this command if you want to know about OSPF neighbors going up or down without turning
on the
debug ospf adjacency command. The log-adj-changes router configuration command provides
a higher level view of the peer relationship with less output. Configure log-adj-changes detail if you
want to see messages for each state change.
To log neighbors going up or down, perform the following steps:
Step 1
If you have not already done so, enter the router configuration mode for the OSPF process you want to
configure by entering the following command:
hostname(config)# router ospf process_id
Step 2 To configure logging for neighbors going up or down, enter the following command:
hostname(config-router)# log-adj-changes [ detail ]
Note Logging must be enabled for the neighbor up/down messages to be sent.
The following example shows how to log neighbors up/down messages:
hostname(config)# router ospf 1
hostname(config-router)#
log-adj-changes detail
Displaying OSPF Update Packet Pacing
OSPF update packets are automatically paced so they are not sent less than 33 milliseconds apart.
Without pacing, some update packets could get lost in situations where the link is slow, a neighbor could
not receive the updates quickly enough, or the router could run out of buffer space. For example, without
pacing packets might be dropped if either of the following topologies exist:
• A fast router is connected to a slower router over a point-to-point link.
•
During flooding, several neighbors send updates to a single router at the same time.
Pacing is also used between resends to increase efficiency and minimize lost retransmissions. You also
can display the LSAs waiting to be sent out an interface. The benefit of the pacing is that OSPF update
and retransmission packets are sent more efficiently.