Parameters
None
Description
Use
compare-different-as-med
to enable the comparison of the MED for paths from peers in
different ASs.
Use
undo compare-different-as-med
to disable the comparison.
The comparison is disabled by default.
If several paths to one destination are available, the path with the smallest MED is selected.
Do not use this command unless associated ASs adopt the same IGP protocol and routing selection
method.
Examples
# In BGP view, enable the comparison of the MED for paths from peers in different ASs.
<Sysname> system-view
[Sysname] bgp 100
[Sysname-bgp] compare-different-as-med
# In BGP-VPN instance view, enable the comparison of the MED for paths from peers in different Ass.
(The VPN has been created.)
<Sysname> system-view
[Sysname] bgp 100
[Sysname-bgp] ipv4-family vpn-instance vpn1
[Sysname-bgp-ipv4-vpn1] compare-different-as-med
confederation id
Syntax
confederation id
as-number
undo confederation id
View
BGP view
Default level
2: System level
Parameters
as-number
: Number of the AS that contains multiple sub-ASs, in the range of 1 to 4294967295.
Description
Use
confederation id
to configure a confederation ID.
Use
undo confederation id
to remove a specified confederation.
By default, no confederation ID is configured.
Configuring a confederation can reduce IBGP connections in a large AS. You can split the AS into
several sub-ASs, and each sub-AS remains fully meshed. These sub-ASs form a confederation. Key
IGP attributes of a route, such as the next hop, MED, local preference, are not discarded when
crossing each sub-AS. The sub-ASs still look like a whole from the perspective of other ASs. This
can ensure the integrity of the former AS, and solve the problem of too many IBGP connections in
the AS.
Related commands:
confederation nonstandard
and
confederation peer-as
.
192