Re: BFD w/ static routes and single-hop eBGP

[Jeffrey Haas <[e-mail]>]

[With my co-chair hat off]

On Tue, Oct 25, 2005 at 01:28:28PM +0300, Pekka Savola wrote:
> I still want to see the details of BFD with:
>  - single-hop static routes
>  - single-hop eBGP

I'd also like to see at the least the BGP/RIP case spelled out in
a little more detail.

In the case of statics, it seems reasonably clear that your BFD session
can be with the nexthop assigned to the static route.

In the case of BGP and RIP, your session probably should be with
the advertising router (RIP) or the peer (BGP) for purposes of
converging the protocol up/down state.  In the case where each of
these protocols use first party nexthops, you will typically need
this session to verify that the nexthop is reachable.  The BFD session
status could then be used to remove routes that can't be active due
to a down session.

The third party nexthop case is the more interesting one.  I believe
you'd want a BFD session for each third party nexthop.

> .. in some document.  At the last meeting, David said that he didn't 
> believe these are necessary as the bfd-generic-01 doc includes this 
> information but I disagree.

In the sense that you can turn on a BFD session with any address you want,
that may be clear.  What's not clear is what you'd want to do per
protocol.  Is that your argument?

> I suggest a section or two either in the main body of the spec or in 
> an appendix either in draft-ietf-bfd-v4v6-1hop or 
> draft-ietf-bfd-generic.

[With my co-chair hat on]

In interest in advancing the base specifications on a timely fashion,
I'd say we wish to have this in the generic document.

-- 
Jeff Haas 
NextHop Technologies