H3C S7500E Series Ethernet Switches Operation Manual

Operation Manual – IPv4 Routing
H3C S7500E Series Ethernet Switches Chapter 6 Routing Policy Configuration
6-3
V. Extended community list
Extended community list (extcommunity-list) applies to BGP only. It involves two
attributes: Route-Target extcommunity for VPN, Source of Origin extcommunity. An
extcommunity-list specifies matching conditions according to the two attributes.
VI. Routing policy
A routing policy is used to match against some attributes in given routing information
and modify the attributes of the information if match conditions are satisfied. It can
reference the above mentioned filters to define its own match criteria.
A routing policy can comprise multiple nodes, which are in logic OR relationship. Each
node is a match unit, and the system compares each node to a packet in the order of
node sequence number. Once a node is matched, the routing policy is passed and the
packet will not go through the next node.
Each node comprises a set of if-match and apply clauses. The if-match clauses
define the match criteria. The matching objects are some attributes of routing
information. The different if-match clauses on a node is in logical AND relationship.
Only when the matching conditions specified by all the if-match clauses on the node
are satisfied, can routing information pass the node. The apply clauses specify the
actions to be performed after the node is passed, concerning the attribute settings for
routing information.
6.1.3 Routing Policy Application
A routing policy is applied in two ways:
z When redistributing routes from other routing protocols, a routing protocol accepts
only routes passing the routing policy.
z When receiving or advertising routing information, a routing protocol uses the
routing policy to filter routing information.
6.2 Routing Policy Configuration Task List
Complete the following tasks to configure a routing policy:
Task
Defining an IPv4 prefix List
Defining an AS Path List
Defining a Community List
Defining Filtering Lists
Defining an Extended Community List