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Catalyst 3550 Multilayer Switch Software Configuration Guide
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Chapter 31 Configuring IP Unicast Routing
Configuring Protocol-Independent Features
To disable redistribution, use the no form of the commands.
The metrics of one routing protocol do not necessarily translate into the metrics of another. For example,
the RIP metric is a hop count, and the IGRP metric is a combination of five qualities. In these situations,
an artificial metric is assigned to the redistributed route. Uncontrolled exchanging of routing information
between different routing protocols can create routing loops and seriously degrade network operation.
If you have not defined a default redistribution metric that replaces metric conversion, some automatic
metric translations occur between routing protocols:
•
RIP can automatically redistribute static routes. It assigns static routes a metric of 1 (directly
connected).
•
IGRP can automatically redistribute static routes and information from other IGRP-routed
autonomous systems. IGRP assigns static routes a metric that identifies them as directly connected.
It does not change the metrics of routes derived from IGRP updates from other autonomous systems.
•
Any protocol can redistribute other routing protocols if a default mode is in effect.
Configuring Policy-Based Routing
You can use policy-based routing (PBR) to configure a defined policy for traffic flows. By using PBR,
you can have more control over routing by reducing the reliance on routes derived from routing
protocols. PBR can determine and implement routing policies that allow or deny paths based on:
•
Identity of a particular end system
•
Application
•
Protocol
You can use PBR to provide equal-access and source-sensitive routing, routing based on interactive
versus batch traffic, or routing based on dedicated links. For example, you could transfer stock records
to a corporate office on a high-bandwidth, high-cost link for a short time while transmitting routine
application data such as e-mail over a low-bandwidth, low-cost link.
Step 3
redistribute protocol [process-id] {level-1 | level-1-2 |
level-2} [metric metric-value] [metric-type type-value]
[match internal | external type-value] [tag tag-value]
[route-map map-tag] [weight weight] [subnets]
Redistribute routes from one routing protocol to another
routing protocol.
Step 4
default-metric number
Cause the current routing protocol to use the same metric
value for all redistributed routes (BGP, RIP, and OSPF).
Step 5
default-metric bandwidth delay reliability loading mtu
Cause the IGRP or EIGRP routing protocol to use the
same metric value for all non-IGRP redistributed routes.
Step 6
no default-information {in | out}
Disable the redistribution of default information between
IGRP processes, which is enabled by default.
Step 7
end
Return to privileged EXEC mode.
Step 8
show route-map
Display all route maps configured or only the one
specified to verify configuration.
Step 9
copy running-config startup-config
(Optional) Save your entries in the configuration file.
Command
Purpose