BGP channel add/remove

[Ondrej Zajicek]

On Fri, Jun 22, 2018 at 09:23:02AM +0000, Arvin Gan wrote:
> Hi All,
> I am using Bird 2.0.2 version, I create a BGP instance with one channel IPV4, that all work normally.  Then I modified configuration file and add new channel IPV6, and using command "configure" under birdc , found the  new added channel IPV6 is not announced to peer and channel ipv6 is down state.  Then I used "restart bgp",  all channels IPV4 and IPV6 are announced, work normally.   I also do another test that delete channel  in configure file and used   "configure", it work normally.
>  Anyone know the difference of actions  between  "configure" and "restart "?   The command "configure" can dynamically modify the BGP protocol configuration, cant the action "configure"  re-announce the added/removed capability  to peer to update ?

Hi

The capabilities (including supported AFIs/SAFIs) can be announced just
during the session establishment, not later. So it is not possible to
really add/remove BGP channels without restarting the session.

Currently the 'configure' adds/removes the channels while do not trigger
restart, so consecutive 'restart' would cause re-establishment.
Obviously, just using 'restart' without 'configure' would not read the
config file and would keep the old setting.

Perhaps we should trigger restart when BGP channels are added/removed
and keep current behavior for 'configure soft'.

-- 
Elen sila lumenn' omentielvo

Ondrej 'Santiago' Zajicek (email: santiago at crfreenet.org)
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"To err is human -- to blame it on a computer is even more so."