Re: [Idr] I-D Action: draft-ietf-idr-rs-bfd-02.txt

Jeffrey Haas <jhaas@pfrc.org> Mon, 20 March 2017 19:58 UTC

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Date: Mon, 20 Mar 2017 16:04:15 -0400
From: Jeffrey Haas <jhaas@pfrc.org>
To: Gert Doering <gert@space.net>
Cc: Robert Raszuk <robert@raszuk.net>, idr wg <idr@ietf.org>
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Subject: Re: [Idr] I-D Action: draft-ietf-idr-rs-bfd-02.txt
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On Thu, Mar 16, 2017 at 08:37:53AM +0100, Gert Doering wrote:
> Optimizing the "route server shall distribute multiple paths" is only
> half of the solution.  More interesting for me is "where do I need to
> point my vendors to, to get them to implement proper black-hole
> detection in the forwarding path, so the BGP NH can be invalidated?"

As noted earlier, the BFD component of the draft is separable and may be
worth a split at some later point if necessary.  It's also the easy part of
the draft.

> (I'm not aware of any gear that will do this right now, as in "if
> IPv4 ARP or IPv6 ND fails, mark NH as invalid and look for other paths
> in BGP" - but I'm always willing to learn)

Having been at the wrong end of quirks of ND/ARP issues, I don't recommend
this as a sufficiently useful mechanism.  

I also suspect the IXPs wouldn't want their customers participating in a
layer 2 OAM mechanism.  This leaves layer 3, which moves us largely to BFD.

Or alternatively ping. Which is gross, but would totally work.

-- Jeff