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Catalyst 3750 SwitchSoftware Configuration Guide
OL-8550-09
Chapter38 Configuring IP Unicast Routing
Configuring ISO CLNS Routing
frequently and IS-IS adjacencies are failing unnecessarily. You can raise the hello multiplier and
lower the hello interval correspondingly to make the hello protocol more reliable without increasing
the time required to detect a link failure.
•Other time intervals:
–
Complete sequence number PDU (CSNP) interval. CSNPs are sent by the designated router to
maintain database synchronization
–
Retransmission interval. This is the time between retransmission of IS-IS LSPs for
point-to-point links.
–
IS-IS LSP retransmission throttle interval. This is the maximum rate (number of milliseconds
between packets) at which IS-IS LSPs are re-sent on point-to-point links This interval is
different from the retransmission interval, which is the time between successive retransmissions
of the same LSP
•Designated router election priority, which allows you to reduce the number of adjacencies required
on a multiaccess network, which in turn reduces the amount of routing protocol traffic and the size
of the topology database.
•The interface circuit type, which is the type of adjacency desired for neighbors on the specified
interface
•Password authentication for the interface
Beginning in privileged EXEC mode, follow these steps to configure IS-IS interface parameters:
Command Purpose
Step1 configure terminal Enter global configuration mode.
Step2 interface interface-id Specify the interface to be configured and enter interface configuration
mode. If the interface is not already configured as a Layer 3 interface, enter
the no switchport command to put it into Layer 3 mode.
Step3 isis metric default-metric [level-1 |
level-2]
(Optional) Configure the metric (or cost) for the specified interface. The
range is from 0 to 63. The default is 10. If no level is entered, the default is
to apply to both Level 1 and Level 2 routers.
Step4 isis hello-interval {seconds |
minimal} [level-1 | level-2]
(Optional) Specify the length of time between hello packets sent by the
switch. By default, a value three times the hello interval seconds is
advertised as the holdtime in the hello packets sent. With smaller hello
intervals, topological changes are detected faster, but there is more routing
traffic.
•minimal—causes the system to compute the hello interval based on the
hello multiplier so that the resulting hold time is 1 second.
•seconds—the range is from 1 to 65535. The default is 10 seconds.
Step5 isis hello-multiplier multiplier
[level-1 | level-2]
(Optional) Specify the number of IS-IS hello packets a neighbor must miss
before the router should declare the adjacency as down. The range is from
3 to 1000. The default is 3. Using a smaller hello-multiplier causes fast
convergence, but can result in more routing instability.
Step6 isis csnp-interval seconds [level-1 |
level-2]
(Optional) Configure the IS-IS complete sequence number PDU (CSNP)
interval for the interface. The range is from 0 to 65535. The default is
10 seconds.