Quick Reference Guide

PowerConnect B-Series TI24X Configuration Guide 651
53-1002269-02
Configuring RIP parameters
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Configuring a RIP neighbor filter
By default, a Layer 3 Switch learns RIP routes from all its RIP neighbors. Neighbor filters allow you
to specify the neighbor routers from which the device can receive RIP routes. Neighbor filters apply
globally to all ports.
To configure a RIP neighbor filters, enter a command such as the following.
PowerConnect(config-rip-router)# neighbor 1 deny any
Syntax: [no] neighbor <filter-num> permit | deny <source-ip-address> | any
This command configures the Layer 3 Switch so that the device does not learn any RIP routes from
any RIP neighbors.
The following commands configure the Layer 3 Switch to learn routes from all neighbors except
192.168.1.170. Once you define a RIP neighbor filter, the default action changes from learning all
routes from all neighbors to denying all routes from all neighbors except the ones you explicitly
permit. To deny learning from a specific neighbor but allow all other neighbors, you must add a
filter that allows learning from all neighbors. Be sure to add the filter to permit all neighbors last
(the one with the highest filter number). Otherwise, the software can match on the permit all filter
instead of a filter that denies a specific neighbor, and learn routes from that neighbor.
PowerConnect(config-rip-router)# neighbor 2 deny 192.16.1.170
PowerConnect(config-rip-router)# neighbor 1024 permit any
Changing the route loop prevention method
RIP can use the following methods to prevent routing loops:
• Split horizon – The Layer 3 Switch does not advertise a route on the same interface as the one
on which the router learned the route.
• Poison reverse – The Layer 3 Switch assigns a cost of 16 (“infinite” or “unreachable”) to a
route before advertising it on the same interface as the one on which the router learned the
route. This is the default.
These loop prevention methods are configurable on an individual interface basis. One of the
methods is always in effect on an interface enabled for RIP. If you disable one method, the other
method is enabled.
NOTE
These methods may be used in addition to RIP maximum valid route cost of 15.
To disable poison reverse and enable split horizon on an interface, enter commands such as the
following.
PowerConnect(config)# interface ethernet 1
PowerConnect(config-if-1)# no ip rip poison-reverse
Syntax: [no] ip rip poison-reverse
To disable split horizon and enable poison reverse on an interface, enter commands such as the
following.
PowerConnect(config)# interface ethernet 1
PowerConnect(config-if-1)# ip rip poison-reverse