3com 8807 참조 가이드
500
C
HAPTER
27: BGP C
ONFIGURATION
C
OMMANDS
If there are several routes available to one destination address, the route with
smaller MED parameter can be selected as the final route item.
smaller MED parameter can be selected as the final route item.
Do not use this command unless it is determined that the same IGP and routing
selection mode are adopted by different autonomous systems.
selection mode are adopted by different autonomous systems.
Example
[3Com-bgp] compare-different-as-med
confederation id
Syntax
confederation id as-number
undo confederation id
View
BGP view
Parameter
as-number: The ID of BGP AS confederation. It is equal to the AS number which
contains the AS numbers of multiple sub-ASs. The range is 1 to 65535.
contains the AS numbers of multiple sub-ASs. The range is 1 to 65535.
Description
Use the confederation id command to configure confederation identifier.
Use the undo confederation id command to cancel the BGP confederation
specified by as-number argument.
specified by as-number argument.
By default, the confederation ID is not configured.
Confederation can be adopted to solve the problem of too many IBGP full
connections in a large AS domain. The solution is, first dividing the AS domain into
several smaller sub-ASs, and each sub-ASs remains full-connected. These sub-ASs
form a confederation. Key BGP attributes of the route, such as next hop, MED,
local preference, are not discarded across each sub-ASs. The sub-ASs still look like
a whole from the point of view of a confederation although these sub-ASs have
EBGP relations. This can assure the integrality of the former AS domain, and ease
the problem of too many connections in the domain
connections in a large AS domain. The solution is, first dividing the AS domain into
several smaller sub-ASs, and each sub-ASs remains full-connected. These sub-ASs
form a confederation. Key BGP attributes of the route, such as next hop, MED,
local preference, are not discarded across each sub-ASs. The sub-ASs still look like
a whole from the point of view of a confederation although these sub-ASs have
EBGP relations. This can assure the integrality of the former AS domain, and ease
the problem of too many connections in the domain
Related command: confederation nonstandard, confederation peer-as.
Example
# Confederation 9 consists of four sub-ASs, namely, 38, 39, 40 and 41. Here, the
peer 10.1.1.1 is an internal member of the AS confederation while the peer
200.1.1.1 is an external member of the AS confederation. For external members,
Confederation 9 is a unified AS domain.
peer 10.1.1.1 is an internal member of the AS confederation while the peer
200.1.1.1 is an external member of the AS confederation. For external members,
Confederation 9 is a unified AS domain.
[SW8800] bgp 41
[3Com-bgp] confederation id 9
[3Com-bgp] confederation peer-as 38 39 40
[3Com-bgp] group Confed38 external
[3Com-bgp] peer Confed38 as-number 38
[3Com-bgp] peer 10.1.1.1 group Confed38
[3Com-bgp] group Remote98 external