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Catalyst 3750-X and 3560-X Switch Software Configuration Guide
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Chapter 42 Configuring IP Unicast Routing Configuring ISO CLNS Routing
Configuring IS-IS Global Parameters
These are some optional IS-IS global parameters that you can configure:
• You can force a default route into an IS-IS routing domain by configuring a default route controlled
by a route map. You can also specify other filtering options configurable under a route map.
• You can configure the router to ignore IS-IS LSPs that are received with internal checksum errors
or to purge corrupted LSPs, which causes the initiator of the LSP to regenerate it.
• You can assign passwords to areas and domains.
• You can create aggregate addresses that are represented in the routing table by a summary address
(route-summarization). Routes learned from other routing protocols can also be summarized. The
metric used to advertise the summary is the smallest metric of all the specific routes.
• You can set an overload bit.
• You can configure the LSP refresh interval and the maximum time that an LSP can remain in the
router database without a refresh
• You can set the throttling timers for LSP generation, shortest path first computation, and partial
route computation.
• You can configure the switch to generate a log message when an IS-IS adjacency changes state (up
or down).
• If a link in the network has a maximum transmission unit (MTU) size of less than 1500 bytes, you
can lower the LSP MTU so that routing will still occur.
• The partition avoidance router configuration command prevents an area from becoming partitioned
when full connectivity is lost among a Level1-2 border router, adjacent Level 1 routers, and end
hosts.
Beginning in privileged EXEC mode, follow these steps to configure IS-IS parameters:
Command Purpose
Step 1 configure terminal Enter global configuration mode.
Step 2 clns routing Enable ISO connectionless routing on the switch.
Step 3 router isis Specify the IS-IS routing protocol and enter router configuration mode.
Step 4 default-information originate
[route-map map-name]
(Optional) Force a default route into the IS-IS routing domain.If you enter
route-map map-name, the routing process generates the default route if the
route map is satisfied.
Step 5 ignore-lsp-errors (Optional) Configure the router to ignore LSPs with internal checksum
errors, instead of purging the LSPs. This command is enabled by default
(corrupted LSPs are dropped). To purge the corrupted LSPs, enter the no
ignore-lsp-errors router configuration command.
Step 6 area-password password (Optional Configure the area authentication password, which is inserted in
Level 1 (station router level) LSPs.
Step 7 domain-password password (Optional) Configure the routing domain authentication password, which is
inserted in Level 2 (area router level) LSPs.
Step 8 summary-address address mask
[level-1 | level-1-2 | level-2]
(Optional) Create a summary of addresses for a given level.