System information

Troubleshooting ISO CLNS
Book Title
12-284
ISO CLNS: Redistribution Causes Routing Problems
Symptom: Route redistribution does not work properly and causes routing problems. Traffic does
not get through a router that is redistributing routes between two different routing areas or
domains—typically IS-IS and ISO-IGRP. Observed symptoms range from poor performance to no
communication at all.
Table 12-8 outlines the problems that might cause this symptom and describes solutions to those
problems.
Table 12-8 ISO CLNS: Redistribution Causes Routing Problems
Possible Problem Solution
Misordered sequence
numbers
The sequence numbers used in route-map router configuration commands determine the
order in which conditions are tested. Misordered sequence numbers can cause
redistribution problems.
Step 1 Use the show running-config privileged exec command to display the router
configuration. Look for route-map router configuration command entries.
Step 2 If route-map commands are configured, look at the sequence numbers that are
assigned. Lower sequence numbers are tested before higher sequence numbers,
regardless of the order in which they are listed in the configuration.
Step 3 If conditions are not being tested in the order you want, you must modify the
sequence numbers to change the testing order. The syntax for the route-map
command to adjust the sequence number is as follows:
route-map map-tag {permit | deny} sequence-number
Syntax Description:
• map-tag—Meaningful name for the route map. The redistribute command
uses this name to reference this route map. Multiple route maps can share the
same map tag name. Can either be an expression or a filter set.
• permit—If the match criteria are met for this route map and permit is
specified, the route is redistributed as controlled by the set actions. If the
match criteria are not met, and permit is specified, the next route map with
the same map tag is tested. If a route passes none of the match criteria for the
set of route maps sharing the same name, it is not redistributed by that set.
Misordered sequence
numbers
• deny—If the match criteria are met for the route map and deny is specified,
the route is not redistributed and no further route maps sharing the same map
tag name will be examined.
• sequence-number—Number that indicates the position a new route map is to
have in the list of route maps already configured with the same name. If given
with the no form of this command, it specifies the position of the route map
that should be deleted.