Re: [babel] Mirja Kühlewind's Discuss on draft-ietf-babel-rfc6126bis-12: (with DISCUSS and COMMENT)

Juliusz Chroboczek <> Wed, 08 January 2020 15:15 UTC

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Date: Wed, 08 Jan 2020 16:15:36 +0100
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From: Juliusz Chroboczek <>
To: Mirja Kuehlewind <>
Cc: "" <>, Babel at IETF <>, Alvaro Retana <>, The IESG <>, Martin Vigoureux <>, "STARK, BARBARA H" <>, Teco Boot <>
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Subject: Re: [babel] =?iso-8859-1?q?Mirja_K=FChlewind=27s_Discuss_on_draft-ie?= =?iso-8859-1?q?tf-babel-rfc6126bis-12=3A_=28with_DISCUSS_and_COMMENT=29?=
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> The smaller the time interval are that you use, the higher is the load
> on the network. That means certain configuration would endanger the
> integrity of the network if the network capacity is below the load that
> is generated by the updates and hello.

Mirja -- this is not a transport-layer protocol that is deployed over
a heterogeneous Internet; it's a signalling protocol that is deployed over
the local link.  Since there are no intermediate routers to congest,
congestion control issues are very different from what you are used to.

The amount of signalling traffic that a Babel node generates is minuscule,
on the order of a few hundred bytes per second, a few kB/s in large
networks.  Since there are no intermediate routers to congest, the only
limiting factor is the speed of the local link.

> This is not discussed in appendix B.

Neither does RFC 5340.

There is no concensus whether congestion control for link-local signalling
protocols is a real issue.  If you believe that it is an issue, then
I encourage you to create a WG to deal with the issue in a general manner,
one that applies to OSPF, IS-IS, Babel and even DHCPv6 and ND.  (I know at
least one person who thinks like you, and would probably be interested in
participating; I, for one, would be interested in reviewing any documents
you produce.)

Requiring us to solve this (real or imagined) problem within the Babel WG
is not reasonable, just as it would not be reasonable to request that it
be solved within the OSPF WG.

-- Juliusz