3Com Router User Manual

BGP Configuration Example477
[RouterD-ospf] network 4.0.0.0 0.0.0.255 area 0
[RouterD] bgp 200
[RouterD-bgp] undo synchronization
[RouterD-bgp] peer 194.1.1.2 as-number 100
[RouterD-bgp] peer 194.1.1.2 as-number 200
To make the configuration effective, use the reset bgp all command to reset all 
BGP neighbors. 

478CHAPTER 30: CONFIGURING BGP 

31
CONFIGURING IP ROUTING POLICY
This chapter covers the following topics:
■IP Routing Policy Overview
■Configure IP Routing Policy
■Displaying and Debugging IP Routing Policy
■Configuring IP Routing Policy
■Troubleshooting IP Routing Policy
IP Routing Policy 
OverviewDuring the information exchange with a peer router, the routing protocol may 
need to receive or distribute only part of the route information that complies with 
specific conditions; and to import only part of the route information learned...

480CHAPTER 31: CONFIGURING IP ROUTING POLICY
Routing PolicyA routing policy matches attributes of the given routing information and sets 
some attributes of the routing information when the conditions are matched. A 
routing policy contains several if-match clauses and apply clauses. The 
if-match clauses specify the matching conditions. The apply clauses specify 
the configuration commands that are executed when the filtering conditions 
specified by if-match clauses are satisfied.
Access ListAn access...

Configure IP Routing Policy481
community. Actually, it is a method of grouping according to the destination 
address where the packets are sent. After grouping, the whole group of routing 
information should be distributed, received or imported. The community-list is an 
access list based on community information, used for the BGP protocol. Its 
matching object is the community field of BGP routing information.
Community-list definition is already implemented in BGP configuration. See the 
description of...

482CHAPTER 31: CONFIGURING IP ROUTING POLICY
Define a Matching RulesThe if-match clause defines matching rules to meet the filtering conditions of the 
routing information of the current routing policy. The matched objects are the 
attributes of this routing information.
Perform the following configurations in routing policy view.
Ta b l e 561   Configure a Matching Rules
By default, AS regular expression, community list, interface type, IP address range, 
metric value, OSPF tag field and OSPF routing...

Configure IP Routing Policy483
be filtered through the routing policy unless it matches all if-match clauses of 
this part and it can execute the operation of teh apply sub-clause.
■If an if-match clause is not specified, all routing information is filtered through 
the policy of this node.
Defining an Apply 
ClauseThe apply clause specifies the configuration commands that are executed after 
the filtering conditions specified by the 
if-match clause are satisfied. The 
commands are used to modify...

484CHAPTER 31: CONFIGURING IP ROUTING POLICY
Ta b l e 563   Configure Route Import
By default, a protocol does not import routes from other domains into the its 
routing table.
protocol specifies the source routing domain that can be imported. At present, it 
can import routes domain such as direct, static, RIP, OSPF, OSPF-ASE and BGP.
Software supports importing route information found by the ollowing protocols 
into the route table:
■direct: network segment (or host) route directly connected to the...

Configure IP Routing Policy485
type is the type of ospf external route corresponding to the imported route when 
ospf is importing other protocol routes. 
type 1 refers to external route type 1 and 
type 2 refers to external route type 2.
The metric value of the imported route can be set as the following:
1Specify the metric value with the apply cost command.
2Filter the route with routing policy and set attributes for the route matching the 
conditions.
3If neither of the above is specified, the...

486CHAPTER 31: CONFIGURING IP ROUTING POLICY
Ta b l e 565   Configure Filtering Route Information Received
2Configure filtering the route information being advertised
Define a strategic rule and quote an ACL or prefix-list to filter the routing 
information that does not meet the requirements when receiving routes. Specify 
the protocol to filter only the distributed protocol routing information.
Ta b l e 566   Configure Filtering RouteInformation Being Advertised
By default, no route information...