Ip Routing Policy Overview - Huawei Quidway S5600 Series Operation Manual

Operation Manual – Routing Protocol
Quidway S5600 Series Ethernet Switches-Release 1510
Chapter 6 IP Routing Policy Configuration

6.1 IP Routing Policy Overview

When a router distributes or receives routing information, it may need to implement
some policies to filter the routing information, so as to receive or distribute only the
routing information meeting given conditions. A routing protocol (RIP, for example) may
need to import the routing information discovered by other protocols to enrich its routing
knowledge. While importing routing information from another protocol, it possibly only
needs to import the routes meeting given conditions and set some attributes of the
imported routes to make the routes meet the requirements of this protocol.
For the implementation of a routing policy, you need to define a set of matching rules by
specifying the characteristics of the routing information to be filtered. You can set the
rules based on such attributes as destination address and source address of the
information. The matching rules can be set in advance and then used in the routing
policies to advertise, receive, and import routes.
The S5600 series provide three kinds of filters (Route-policy, ACL, and ip-prefix), which
can be referenced by routing protocols. The following sections introduce these filters.
I. Route-policy
A route policy is used to match some attributes with given routing information and the
attributes of the information will be set if the conditions are satisfied.
A route policy can comprise multiple nodes. Each node is a unit for matching test, and
the nodes will be matched in the order of their node numbers. Each node comprises a
set of if-match and apply statements. The if-match statements define the matching
rules. The matching objects are some attributes of routing information. The relationship
among the if-match statements for a node is "AND". As a result, a matching test
against a node is successful only when all the matching conditions specified by the
if-match statements in the node are satisfied. The apply statements specify the
actions performed after a matching test against the node is successful, and the actions
can be the attribute settings of routing information.
The relationships among different nodes in a route-policy are "OR". As a result, the
system examines the nodes in the route-policy in sequence, and once the route passes
a node in the route-policy, it will pass the matching test of the route-policy without
entering the test of the next node.
II. ACL
The S5600 series support four types of ACLs: advanced, basic, user-defined, and layer
2 ACLs.
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Chapter 6 IP Routing Policy Configuration