Subject: Re: [Idr] draft-uttaro-idr-bgp-persistence-01 as IDR WG document - 3 more weeks

From: Jeffrey Haas <[email-masked]>
Date: Tue, 3 Jul 2012 09:09:08 -0400

Enke,

On Sat, Jun 23, 2012 at 07:58:49PM -0700, Enke Chen wrote:
> Again, GR allows stale paths to be kept for a short duration.  I do
> not feel comfortable to have stale paths in the routing system for
> hours or days.  That would make BGP semi-static and semi-dynamic.
> The implication is non-trivial, as pointed by others.

It is worth noting that the scenario best covered by the persistence draft
is when the impacted reachability is semi-static.

In my opinion, a significant amount of the heat of this discussion comes
from the well placed concerns that such a mechanism isn't well suited to
highly dynamic routing information.  There is also a lot of concern about
when the routing information in question starts to get far enough away from
its home network where the scope of whether something is stale is important
or not.

But in the case of semi-static routing data, some sort of "route stickiness"
mechanism is probably appropriate to cover outages in redudnant
infrastructure.  The primary challenge as protocol developers is how to
properly scope such a feature, especially in a protocol that is inter-domain
by nature.

-- Jeff