Re: [Idr] WG adoption call for draft-merciaz-idr-bgp-bfd-strict-mode-02.txt (9/2 to 9/17/2019)

Jeffrey Haas <jhaas@pfrc.org> Wed, 11 September 2019 14:47 UTC

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Date: Wed, 11 Sep 2019 10:49:56 -0400
From: Jeffrey Haas <jhaas@pfrc.org>
To: Robert Raszuk <robert@raszuk.net>
Cc: "Mercia Zheng (merciaz)" <merciaz@cisco.com>, "idr@ietf.org" <idr@ietf.org>, Susan Hares <shares@ndzh.com>
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Subject: Re: [Idr] WG adoption call for draft-merciaz-idr-bgp-bfd-strict-mode-02.txt (9/2 to 9/17/2019)
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Robert,

On Tue, Sep 10, 2019 at 08:46:22PM +0200, Robert Raszuk wrote:
> If you really want to make it work for IBGP (other then corner p2p use
> cases) you need to encap both BFD and BGP into UDP/IP header and treat as
> one flow. I don't see any issue with that.

Aside from some radical changes to BGP transport.  That's a non-starter, and
not a problem we're intending to address.

> And last bringing down the BGP session to RRs just because BFD in strict
> mode on that session got a hiccup serves no good.

As I noted in the last response, there's a number of caveats.  Your use case
may be different than someone else's.  If you don't like it - don't do that.

Again, BFD gets used both in single and multi-hop situations for BGP.  We're
only addressing where in the state machine it's used, not the use cases.
And very intentionally, not prohibiting existing use cases.

> To detect remote next hop liveness you have different mechanisms in place.

See draft-ietf-idr-rs-bfd for some discussion on that.

-- Jeff