Set As-Path; Set Comm-List Delete - NETGEAR M6100 Series Reference Manual

set as-path

To prepend one or more AS numbers to the AS path in a BGP route, use the set as-path
command in Route Map Configuration mode. This command is normally used to insert one or
more instances of the local AS number at the beginning of the AS_PATH attribute of a BGP
route. Doing so increases the AS path length of the route. The AS path length has a strong
influence on BGP route selection. Changing the AS path length can influence route selection
on the local router or on routers to which the route is advertised.
When prepending an inbound route, if the first segment in the AS_PATH of the received route
is an AS_SEQUENCE, as-path-string is inserted at the beginning of the sequence. If the
first segment is an AS_SET, as-path-string is added as a new segment with type
AS_SEQUENCE at the beginning of the AS path. When prepending an outbound route to an
external peer, as-path-string follows the local AS number, which is always the first ASN.
Format
set as-path prepend as-path-string
Mode Route Map Configuration
Parameter Description
as-path-string A list of AS path numbers to insert at the beginning of the AS_PATH attribute of matching BGP
routes. To prepend more than one AS number, separate the ASNs with a space and enclose the
string in quotes. Up to ten AS numbers may be prepended.
Command example:
The following example prepends three instances of an external peer's AS number to paths
that are received from that peer, causing routes that are learned from this peer less likely to
be chosen as the best path:
(NETGEAR Switch)# config
(NETGEAR Switch)# route-map ppAsPath
(NETGEAR Switch)# set as-path prepend "2 2 2"
(NETGEAR Switch)# exit
(NETGEAR Switch)# router bgp 1
(NETGEAR Switch)# neighbor 172.20.1.2 remote-as 2
(NETGEAR Switch)# neighbor 172.20.1.2 route-map ppAsPath in
no set as-path
To remove a set command from a route map, use the no set as-path command.
Format
no set as-path prepend as-path-string
Mode Route Map Configuration

set comm-list delete

To remove BGP communities from an inbound or outbound UPDATE message, use the set
comm-list delete command in Route Map Configuration mode. A route map with this set
M6100 Series Switches
Routing Commands
665