Hi Ingemar, Arjuna is conducting the latest simulations on the topic of VoIP-DCCP interaction and therefore he should have the best view of the current state of affairs. Let me just point you to another draft that addresses how restart after idle periods of different lenghts is handled by the TFRC congestion control method: http://www.ietf.org/internet-drafts/draft-ietf-dccp-rfc3448bis-02.txt A difference to consider between the mechanism specified in this draft and CCID3 or CCID4 is that the later use a window counter mechanism for timing the feedback packets which might somehow perform differently after long idle periods. Regards, Vlad On 8/15/07, Ingemar Johansson S (LU/EAB) <ingemar.s.johansson@xxxxxxxxxxxx> wrote: > Hi > > I am trying to get a deeper understanding of the DCCP protocol. However I am a little lost on the different CCID's. > > I have a typical VoIP scenario where packets are transmitted 50 packets per second with a payload size of ~30bytes. Also one can assume that DTX is used and that periodic comfort noise update packets are transmitted at a rate of ~5 packet/second. > > In terms of congestion avoidance it is possible to reduce the payload size to 10bytes and the packet rate can be reduced to 10 packets/second. > It is not acceptable to reduce the packet rate to below 10 packets/second for active speech segments. > > An additional requirement is that the feedback rate must be kept fairly low. > > Given the outline above. What CCID can be used ?. > Two drafts catch my interest, namely > http://tools.ietf.org/wg/dccp/draft-ietf-dccp-tfrc-faster-restart/ > And > http://tools.ietf.org/wg/dccp/draft-floyd-dccp-ccid4-01.txt > Do any of the above meet the requirements ? > > Regards > Ingemar > ******************************************* > Ingemar Johansson > Senior Research Engineer, IETF "nethead" > EAB/TVP - Multimedia Technologies > Ericsson Research Ericsson AB > Box 920 S-971 28 Luleå, Sweden > Tel: +46 (0)8 4043042 > ECN: 850-43042 > Mobile: +46 (0)730 783289 > MSN: ingemarjohansson1965@xxxxxxxxxxx > ******************************************* > > >
