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Re: OMB: IPv6 by June 2008

  • From: David Andersen
  • Date: Tue Jul 12 21:36:51 2005


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