Re: [v6ops] Thoughts on draft-yourtchenko-ra-dhcpv6-comparison

Ole Troan <otroan@employees.org> Mon, 16 December 2013 21:46 UTC

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From: Ole Troan <otroan@employees.org>
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Date: Mon, 16 Dec 2013 22:46:03 +0100
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To: Owen DeLong <owen@delong.com>
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Subject: Re: [v6ops] Thoughts on draft-yourtchenko-ra-dhcpv6-comparison
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Owen,

>>>> Second: some of the text you have now deals with link-layer performance. However, I think that since these are configuration protocols, the attributes that are important are primarily semantics, not performance or implementation.
>>> 
>>> Lorenzo, this is kind of a puzzling position to take.   There are lots of ways to do things with really nice semantics that fall on their face for performance reasons.   So I think performance questions are in scope.
>>> 
>>> Oh, of course - in general, they are. But here the protocols used are so similar that there is little substantive difference in performance.
>> 
>> could you expand on that?
>> I see the scaling properties on a multicast capable link very different between the two.
>> take a multicast capable link with 10K nodes on it, where power has just come back.
>> a few hundred RS/RA messages, at least 40K DHCPv6 messages.
> 
> I'm trying to think of a multi-user network technology still in use today where 40,000 packets over a couple of minutes time is likely to be a significant load and I'm failing to come up with one.

indeed, I wasn't thinking of link-congestion, but processing time. on the DHCP server and the first-hop switches and routers.
do you agree that RS/RA and DHCP scales quite differently in this scenario?
(then we can argue later if the differences matter or not).

cheers,
Ole