Cisco Catalyst 3560-X Series, Software Configuration Manual

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Catalyst 3750-X and 3560-X Switch Software Configuration Guide
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Chapter 1 Configuring IP Unicast Routing
Configuring Protocol-Independent Features
Using Route Maps to Redistribute Routing Information
The switch can run multiple routing protocols simultaneously, and it can redistribute information from
one routing protocol to another. Redistributing information from one routing protocol to another applies
to all supported IP-based routing protocols.
You can also conditionally control the redistribution of routes between routing domains by defining
enhanced packet filters or route maps between the two domains. The
match and set route-map
configuration commands define the condition portion of a route map. The match command specifies that
a criterion must be matched. The set command specifies an action to be taken if the routing update meets
the conditions defined by the match command. Although redistribution is a protocol-independent
feature, some of the
match and set route-map configuration commands are specific to a particular
protocol.
One or more match commands and one or more set commands follow a route-map command. If there
are no match commands, everything matches. If there are no set commands, nothing is done, other than
the match. Therefore, you need at least one match or set command.
Note
A route map with no set route-map configuration commands is sent to the CPU, which could cause high
CPU utilization.
You can also identify route-map statements as permit or deny . If the statement is marked as a deny, the
packets meeting the match criteria are sent back through the normal forwarding channels
(destination-based routing). If the statement is marked as permit, set clauses are applied to packets
meeting the match criteria. Packets that do not meet the match criteria are forwarded through the normal
routing channel.
You can use the BGP route map continue clause to execute additional entries in a route map after an
entry is executed with successful match and set clauses. You can use the continue clause to configure
and organize more modular policy definitions so that specific policy configurations need not be repeated
within the same route map. Beginning in Cisco IOS Release 12.2(37)SE, the switch supports the
continue clause for outbound policies. For more information about using the route map continue clause,
see the BGP Route-Map Continue Support for an Outbound Policy feature guide for Cisco IOS
Release 12.4(4)T.
Although each of Steps 3 through 14 in the following section is optional, you must enter at least one
match route-map configuration command and one set route-map configuration command.