Netgear XCM8810 - 8800 SERIES 10-SLOT CHASSIS SWITCH ユーザーズマニュアル

for EBGP multihop. Using the loopback interface eliminates multiple, unnecessary route 
changes. 

Looped AS_Path Attribute

When a BGP speaker receives a route from its neighbor, it must validate the AS_Path 
attribute to ensure that there is no loop in the AS_Path. When a BGP speaker finds it's own 
AS-number in the received BGP route's AS_Path attribute, it is considered as "Looped AS 
Path" and by default, the associated BGP routes are silently discarded. 

There are certain cases (such as in a spoke and hub topology) where it becomes necessary 
to accept and process BGP routes with looped AS_Path attribute. This feature enables you 
to control the processing of BGP routes with looped AS_Path attribute. You can do the 
following: 

Allow the route with looped AS_Path to be accepted 

Allow the route with looped AS_Path to be accepted only if the number of occurrences of 

its own AS-Number is less than or equal to 

N

, where 

N

 is an user-configurable unsigned 

integer configured

Silently discard the route with looped AS_Path 

BGP Peer Groups

You can use BGP peer groups to group together up to 512 BGP neighbors. All neighbors 
within the peer group inherit the parameters of the BGP peer group. The following mandatory 
parameters are shared by all neighbors in a peer group:

remote AS

source-interface

route-policy

send-community

next-hop-self

Each BGP peer group is assigned a unique name when it is created. To create or delete peer 
groups, use the following commands:

create bgp peer-group <peer-group-name>

 

delete bgp peer-group <peer-group-name>

Changes made to the parameters of a peer group are applied to all neighbors in the peer 
group. Modifying the following parameters will automatically disable and enable the 
neighbors before changes take effect:

remote-as

timer

source-interface

soft-in-reset