From: Andi Kleen <andi@firstfloor•org>
To: David Miller <davem@davemloft•net>
Cc: gdt@gdt•id.au, netdev@vger•kernel.org
Subject: Re: UDP path MTU discovery
Date: Sun, 28 Mar 2010 10:41:37 +0200 [thread overview]
Message-ID: <87bpe825z2.fsf@basil.nowhere.org> (raw)
In-Reply-To: <20100325.202424.201654947.davem@davemloft.net> (David Miller's message of "Thu, 25 Mar 2010 20:24:24 -0700 (PDT)")
David Miller <davem@davemloft•net> writes:
> From: Glen Turner <gdt@gdt•id.au>
> Date: Fri, 26 Mar 2010 10:32:31 +1030
>
>> This differs from TCP, where it is the kernel -- and not
>> the application -- which organises retransmission. On
>> receiving a ICMP Fragmentation Needed the kernel can
>> immediately re-probe the path MTU wiht no waiting for
>> an exponential timer to expire.
>
> So the argument is, the kernel TCP does retransmission smart,
> userspace UDP apps do it stupidly, so let's turn off the feature
> instead of fixing userspace.
>
> Right?
>
> Sorry, fix this correctly in the user apps. Putting the
> blame on UDP path MTU discovery is placing it in the
> wrong spot.
It means though that all IPv6 UDP applications essentially have
to implement path mtu discovery support (which is non trivial)
Will be likely a long time until they're all fixed.
Seems like a big hole not considered by the IPv6 designers?
-Andi
--
ak@linux•intel.com -- Speaking for myself only.
next prev parent reply other threads:[~2010-03-28 8:41 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 [this message]
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
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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