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CHAPTER 19
Configuring Policy Options
Configuring an AS Path in a BGP Routing Policy (NSM Procedure)
Copyright © 2010, Juniper Networks, Inc.
Configuring an AS Path in a BGP Routing Policy (NSM Procedure) on page 243
Configuring an AS Path Group in a BGP Routing Policy (NSM Procedure) on page 244
Configuring a Community for use in BGP Routing Policy Conditions(NSM
Procedure) on page 245
Configuring a BGP Export Policy Condition (NSM Procedure) on page 246
Configuring Flap Damping to Reduce the Number of BGP Update Messages(NSM
Procedure) on page 247
Configuring a Routing Policy Statement (NSM Procedure) on page 249
Configuring Prefix List (NSM Procedure) on page 250
An autonomous system (AS) path is a path to a destination. An AS path consists of the
AS numbers of all the network devices that a packet traverses if it takes the associated
route to a destination. The AS numbers are assembled in a sequence, or path, that is
read from right to left. For example, for a packet to reach a destination using a route with
an AS path 5 4 3 2 1, the packet first traverses AS 1 and so on until it reaches AS 5, which
is the last AS before its destination.
You can define a match condition based on all of or portions of the AS path. You can
create a named AS path and then include it in a BGP routing policy.
To configure an AS path for a BGP routing policy in NSM:
In the navigation tree, select
1.
In the
list, double-click the device to select it.
Devices
2.
Click the
3.
Configuration
In the configuration tree, expand
4.
Select
As Path
.
5.
Add or modify the parameters as specified in Table 125 on page 244.
6.
Click one:
7.
OK—To save the changes.
Device Manager > Devices
tab.
.
Policy Options
.
243
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