Brocade Multi-Service IronWare Routing Configuration Guide (Supporting R05.6.00) - Manual (Page 350)

322 Multi-Service IronWare Routing Configuration Guide
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Configuring RIP parameters
Configuring a RIP neighbor filter
By default, a Brocade device learns RIP routes from all its RIP neighbors. Neighbor filters allow you
to specify the neighbor routers from which the Brocade 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.
Brocade(config-rip-router)# neighbor 1 deny any
Syntax: [no] neighbor filter-num permit | deny source-ip-address | any
This command configures the Brocade device so that the device does not learn any RIP routes from
any RIP neighbors.
The following commands configure the Brocade device 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. Thus, to deny learning from a specific neighbor but allow all other neighbors, you must add
a filter that allows learning from all neighbors. Make sure you add the filter to permit all neighbors
as the last filter (the one with the highest filter number). Otherwise, the software can match on the
permit all filter before a filter that denies a specific neighbor, and learn routes from that neighbor.
Brocade(config-rip-router)# neighbor 2 deny 192.168.1.170
Brocade(config-rip-router)# neighbor 1024 permit any
Changing the route loop prevention method
RIP uses the following methods to prevent routing loops:
• Split horizon – The Brocade device does not advertise a route on the same interface as the
one on which the Brocade device learned the route. This is the default.
• Poison reverse – The Brocade device assigns a cost of 16 (“infinite” or “unreachable”) to a
route before advertising it on the same interface as the one on which the Brocade device
learned the route.
These loop prevention methods are configurable on a global basis as well as on an individual
interface basis. One of the methods is always in effect on an interface enabled for RIP. Thus, if you
disable one method, the other method is enabled.
NOTE
These methods are in addition to RIP’s maximum valid route cost of 15.
To disable poison reverse and enable split horizon on a global basis, enter the following command.
Brocade(config-rip-router)# no poison-reverse
Syntax: [no] poison-reverse
To disable poison reverse and enable split horizon on an interface, enter commands such as the
following.
Brocade(config-if-e10000-1/1)# no ip rip poison-reverse
Syntax: [no] ip rip poison-reverse
To disable split horizon and enable poison reverse on an interface, enter the command such as the
following.
Brocade(config-if-e10000-1/1)# ip rip poison-reverse