Cisco IE 4000, Software Configuration Manual

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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 causes 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. 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” section in the IP Routing: BGP Configuration Guide, Cisco IOS Release 15M&T .
Note: 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.
BEFORE YOU BEGIN
You should know your network design and how you want traffic to flow through it before configuring route redistribution
or policy-based routing.