From: Andi Kleen <andi@firstfloor.org>
To: Rick Jones <rick.jones2@hp.com>
Cc: Andi Kleen <andi@firstfloor.org>, Glen Turner <gdt@gdt.id.au>,
netdev@vger.kernel.org
Subject: Re: UDP path MTU discovery
Date: Mon, 29 Mar 2010 22:14:31 +0200 [thread overview]
Message-ID: <20100329201431.GH20695@one.firstfloor.org> (raw)
In-Reply-To: <4BB0DCF6.9020401@hp.com>
On Mon, Mar 29, 2010 at 10:01:42AM -0700, Rick Jones wrote:
> >In theory one could probably add some hack in the the kernel UDP code
> >to hold one packet and retransmit it immediately with fragments when
> >the ICMP comes in. However that would be quite far in behaviour from
> >traditional UDP and be considered very ugly. It could also mess up
> >congestion avoidance schemes done by the application.
> >
> >Still might be preferable over rewriting zillions of applications?
>
> But which of the last N datagrams sent by the application should be
> retained for retransmission? It could be scores if not hundreds of
> datagrams depending on the behaviour of the application and the latency to
> the narrow part of the network.
Yes, if there's a large window you lose. I guess it would make protocols
like DHCP work at least ("transactional UDP" as the original poster called it)
I don't know if it would fix enough applications to be worth
implementing. The only way to find out would be to try I guess.
I don't have any better ideas.
> That the IPv6 specification was heavily "influenced" by "the router guys"
> seems increasingly clear...
Yes it sounds like the IETF didn't completely think that through.
-Andi
--
ak@linux.intel.com -- Speaking for myself only.
next prev parent reply other threads:[~2010-03-29 20:14 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-26 0:02 UDP path MTU discovery Glen Turner
2010-03-26 0:53 ` Rick Jones
2010-03-26 3:26 ` David Miller
2010-03-26 17:48 ` Rick Jones
2010-03-31 23:42 ` Glen Turner
2010-03-31 23:51 ` Hagen Paul Pfeifer
2010-04-01 0:06 ` Rick Jones
2010-03-26 3:24 ` David Miller
2010-03-28 8:41 ` Andi Kleen
2010-03-31 23:57 ` Glen Turner
2010-04-01 0:57 ` Andi Kleen
2010-03-28 8:50 ` Andi Kleen
2010-03-29 17:01 ` Rick Jones
2010-03-29 20:14 ` Andi Kleen [this message]
2010-03-29 20:25 ` Rick Jones
2010-03-29 20:50 ` Edgar E. Iglesias
2010-03-29 21:01 ` Rick Jones
2010-03-29 21:29 ` Eric Dumazet
2010-03-29 23:38 ` Templin, Fred L
2010-03-30 5:20 ` Andi Kleen
2010-03-30 6:06 ` Eric Dumazet
2010-03-30 6:16 ` Andi Kleen
2010-03-30 6:17 ` UDP path MTU discovery II Andi Kleen
2010-03-30 6:16 ` UDP path MTU discovery Edgar E. Iglesias
2010-03-30 6:19 ` Andi Kleen
2010-03-30 8:20 ` Edgar E. Iglesias
2010-03-30 14:12 ` Andi Kleen
2010-03-30 22:04 ` Edgar E. Iglesias
2010-03-30 15:58 ` Templin, Fred L
2010-03-30 16:06 ` Andi Kleen
2010-03-31 23:43 ` Glen Turner
2010-04-01 0:55 ` Andi Kleen
2010-04-02 5:41 ` Glen Turner
2010-04-04 10:25 ` Andi Kleen
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