[82347] in North American Network Operators' Group
Re: OMB: IPv6 by June 2008
daemon@ATHENA.MIT.EDU (David Andersen)
Tue Jul 12 21:36:04 2005
In-Reply-To: <20050712175248.GA14537@OZoNE.TZoNE.ORG>
Cc: NANOG list <nanog@merit.edu>,
Iljitsch van Beijnum <iljitsch@muada.com>
From: David Andersen <dga+@cs.cmu.edu>
Date: Tue, 12 Jul 2005 21:35:37 -0400
To: Phillip Vandry <vandry@TZoNE.ORG>
Errors-To: owner-nanog@merit.edu
On Jul 12, 2005, at 1:52 PM, Phillip Vandry wrote:
>
> How are people making the case for IPv6 with popular applications like
> voice?
>
> With G.711 and 20ms voice samples, with IPv4 you get:
>
> 20 bytes IP + 8 bytes UDP + 12 bytes RTP + 160 bytes payload
> 20% overhead.
>
> 40 bytes IP + 32 bytes shim6 8 bytes UDP + 12 bytes RTP +
> 160 bytes payload
> 36.5% overhead
>
> Almost twice as much overhead is a much tougher pill to swallow. I
> would
> try to stay with IPv4 as long as I could. Even without adding shim6
> into the picture you're taking a significant penalty.
Even standard IP headers are a pretty high overhead for VoIP,
particularly if you're doing very high compression to try to get the
samples to squeeze into a low bandwidth channel. Enter IP header
compression, which is shockingly effective at compressing IP headers of
all sorts... if you've dedicated 128 bits for the address, and it's
still just as static as it was in IPv4, it'll compress to just the same
amount. This is an easy technical problem to solve.
-Dave
