Last Mile QoS WAS: RE: QOS or more bandwidth

Tue May 29 22:16:43 UTC 2001

On Tue, 29 May 2001, Rafi Sadowsky wrote:

> Hi
>
>  Sorry about the previous  (content free :-( ) Email
> May I suggest reading (and following links from)
>
>   <http://www.cisco.com/warp/public/788/voice-qos/voip-mlppp.html>
>
> (Scanning for "cRTP" & "Interleaving" should be useful)

Ya, it is funny because cisco was one of the authors of CRTP (RFC 2508)
and they don't comply with the RFC on any of their products. CRTP is
great, but frankly it does not help at all without other changes. Lets say
we have 10 ms sample of G.726 that is 40 bytes + 2 byte CRTP header + 8
byte AAL5, we are still at two cells and just have more space for padding.
What I am doing is changing the frame size to odd sizes like 9.5 ms giving
me a 38 byte payload + 2 byte CRTP + 8 byte AAL5, fits in one ATM cell.

-Nathan