Re: BFD WG adoption for draft-haas-bfd-large-packets

"Reshad Rahman (rrahman)" <> Mon, 29 October 2018 16:17 UTC

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From: "Reshad Rahman (rrahman)" <>
To: Jeffrey Haas <>
CC: "Les Ginsberg (ginsberg)" <>, "Naiming Shen (naiming)" <>, "" <>
Subject: Re: BFD WG adoption for draft-haas-bfd-large-packets
Thread-Topic: BFD WG adoption for draft-haas-bfd-large-packets
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Date: Mon, 29 Oct 2018 16:17:51 +0000
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Hi Jeff,

I'd be fine with the text below on BFD echo in the discussion section. 


On 2018-10-29, 11:36 AM, "Jeffrey Haas" <> wrote:

    On Fri, Oct 26, 2018 at 06:32:26PM +0000, Reshad Rahman (rrahman) wrote:
    >On 2018-10-25, 11:38 AM, "Jeffrey Haas" <> wrote:
    > >     The draft I had previously worked on with Xiao Min discussing probing using
    > >     BFD Echo had the concept of probes that would happen wherein the session is
    > >     not torn down.  The example carries similarly with the "send occasional".
    > <RR> We discussed use of echo at IETF102. The large-packets draft mentions
    > that echo can only be used for single-hop, hence the need for padding the
    > control packets. But isn't single-hop Albert's main use-case? 
    It's Albert's primary use case.  And, I think a common related one is
    protecting tunnels of various flavors; e.g. GRE or IPsec.
    > I believe we
    > should add the echo option in the large-packets draft, it has the benefit
    > that you get the desired functionality even if only 1 side of the WAN link
    > supports echo. I realize not all implementations support echo so they
    > might have to do pad control packets instead.
    While I don't think Albert or I would have any objections to adding Echo
    discussion in the existing document, we perhaps risk running into one of the
    issues Xiao and I had briefly discussed.  Echo is intentionally
    under-specified in RFC 5880 et seq.  While it's possible that we can simply
    put in a discussion section that says "if you use Echo mode with similar
    padding, you can get similar benefit", I think that may be as far as we want
    to go.
    The related observation is that nothing stops an Echo implementation from
    doing this with no changes to the protocol. :-)
    -- Jeff