[c-nsp] behavior of BGP when new address families are enabled (BGP dynamic capability)

[Tassos Chatzithomaoglou]

Does anyone have any recorded references regarding the behavior of BGP when new address families are enabled?
I'm mostly interested in VPNv6 and IPv6 address families on 7200s, ASR1k, ASR9k, CRS.

In almost all of the cases i have done it myself, i have seen the BGP session reseting, but i was wondering if i'm doing something wrong or there is an option to preconfigure it but enable it at a later time, probably doing just a manual reset of the BGP session.

As a sidenote, i had recently a look at draft-ietf-idr-dynamic-cap (which defines capability code 67 according to http://www.iana.org/assignments/capability-codes/capability-codes.xhtml). This draft is being discussed for over 10 years in IETF, but has expired since last year. There was also a similar capability code 66, which has been deprecated.

Although written by Cisco, i could only find a Nexus reference (http://www.cisco.com/en/US/partner/docs/switches/datacenter/sw/6_x/nx-os/unicast/configuration/guide/l3_advbgp.html#wp1082963)
On the hand, Juniper seems to provide more related docs:
http://www.juniper.net/techpubs/en_US/junose12.3/information-products/topic-collections/swconfig-bgp-mpls/index.html?id-80976.html
http://www.juniper.net/techpubs/software/erx/erx41x/swconfig-routing-vol2/html/bgp-config14.html
Also, vyatta seems to support that:
http://docs.vyatta.com/current/BGP/wwhelp/wwhimpl/common/html/wwhelp.htm#href=Neighbors.06.29.html&single=true

Can anyone provide any inside info what we should expect in this area?

-- 
Tassos