Ip Routing Policy; Introduction To Routing Policy - Edge-Core ES3628EA User Manual

Static route
RIP
OSPF ASE
IBGP
EBGP
Unknown route

13.2 IP Routing Policy

13.2.1 Introduction To Routing Policy

Some policies have to be applied when the router publishing and receiving routing
messages so to filter routing messages, such as only receiving or publishing routing
messages meets the specified conditions. A routing protocol maybe need redistribute
other routing messages found by other protocols such as OSPF so to increase its own
routing knowledge; when the router redistributing routing messages from other routing
protocols there may be only part of the qualified routing messages is needed, and some
properties may have to be configured to suit this protocol.
To achieve routing policy, first we have to define the characteristics of the routing
messages to be applied with routing policies, namely define a group matching rules. We
can configure by different properties in the routing messages such as destination address,
the router address publishing the routing messages. The matching rules can be
previously configured to be applied in the routing publishing, receiving and distributing
policies.
Five filters are provided in ES3628EA switch: route-map, acl, as-path, community-list
and ip-prefix for use. We will introduce each filter in following sections:
1. route-map
For matching certain properties of the specified routing information and setting some
routing properties when the conditions are fulfilled.
Route-map is for controlling and changing the routing messages while also
controlling the redistribution among routes. A route-map consists of a series of match and
set commands in which the match command specifies the conditions required matching,
and the set command specifies the actions to be taken when matches. The route-map is
also for controlling route publishing among different route process. It can also used on
policy routing which select different routes for the messages other than the shortest
route.
A group matches and set clauses make up a node. A route-map may consist of
several nodes each of which is a unit for matching test. We match among nodes with by
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