turning off BGP capability 65

[mayambanzumba]

Hi,

Is it possible to stop a router advertising BGP capability 65(Support for 4-octet AS number capability, RFC4893)in the BGP OPEN meesage?

Is it possible to turn this capability off per neighbor within the IPV4 address family, as some of the devices we need to peer to do not currently support that feature.

Thanks

Mayamba

[Reza Sharifi]

Hi Mayamba,

I don't think there is a command to turn it off but this should not be an issue as:

The transit across the OLD BGP domains leaves the NEW_AS_PATH untouched, and prepends 16-bit AS values to the AS_PATH. In other words, OLD BGP behaves as it always has. The NEW_AS_PATH is passed through the OLD realm as an opaque bit block.

Have a look at this doc for more info:

http://www.cisco.com/web/about/ac123/ac147/archived_issues/ipj_9-1/autonomous_system_numbers.html

HTH

Reza