netdev - Re: [RFC] IP_MAX

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Message-ID: <1356114879.21834.7709.camel@edumazet-glaptop>
Date:	Fri, 21 Dec 2012 10:34:39 -0800
From:	Eric Dumazet <erdnetdev@...il.com>
To:	Rick Jones <rick.jones2@...com>
Cc:	David Miller <davem@...emloft.net>, netdev <netdev@...r.kernel.org>
Subject: Re: [RFC] IP_MAX_MTU value

On Fri, 2012-12-21 at 10:19 -0800, Rick Jones wrote:

> If you go beyond the protocol limit of an IPv4 datagram, won't it be 
> necessary to  start being a bit more conditional on IPv4 vs IPv6?
> 

This IP_MAX_MTU is really an IPv4 thing (static to net/ipv4/route.c)


> 
> 99 times out of 10 I will assert that faster is better, but do we need 
> another 50% for UDP over loopback with that large a message size?

Well, I only didnt understand why sending 65507 UDP messages had to use
fragments. I didnt care of performance at this point, only tried to have
an reasonable explanation.

It turns out its a strange limitation.




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