Juniper JUNOSE 11.2.X BGP AND MPLS, Руководство по настройке

Страница: 129 / 742

and want to fill the Adj-RIBs-Out table for that peer group with the results of the new
policy, you must use the
clear ip bgp peer-group command to perform a hard clear or
outbound soft clear of the peer group. You cannot merely perform a hard clear or
outbound soft clear for individual peer group members because that causes BGP to
resend only the contents of the Adj-RIBs-Out table.
•
Use the no version to send only standard communities to a BGP neighbor. Use the
default version to remove the explicit configuration from the peer or peer group and
reestablish inheritance of the feature configuration.
•
See neighbor send-community.
set community
•
Use to set the community attribute in BGP updates.
•
You can specify a community list number in the range 1–4294967295, or in the new
community format of
AA : NN , or one of the following well-known communities:
•
local-as —Prevents advertisement outside the local AS
•
no-advertise —Prevents advertisement to any peer
•
no-export —Prevents advertisement beyond the BGP confederation boundary
•
Alternatively, you can use the list keyword to specify the name of a community list
that you previously created with the ip community-list command.
•
Example
host1(config)# route-map nyc1 permit 10
host1(config-route-map)# set community no-advertise
•
Use the none keyword to remove the community attribute from a route.
•
Use the no version to delete the set clause from a route map.
•
See set community.
Community Lists
A community list is a sequential collection of permit and deny conditions. Each condition
describes the community number to be matched. If you issued the
ip bgp-community
new-format command, the community number is in AA : NN format; otherwise it is in
decimal format.
The router tests the community attribute of a route against the conditions in a community
list one by one. The first match determines whether the router accepts (the route is
permitted) or rejects (the route is denied) a route having the specified community.
Because the router stops testing conditions after the first match, the order of the
conditions is critical. If no conditions match, the router rejects the route.
Consider the network structure shown in Figure 27 on page 94.
93 Copyright © 2010, Juniper Networks, Inc.
Chapter 1: Configuring BGP Routing