Hi Francois,

Have you checked the Implementors Guide from the 09/98 meeting?

For proposed alternative channels from called to calling, alternatives have the same sessionId, mediaChannel (RTP address), and mediaControlChannel (RTCP address). A unique fwdLCN is assigned to the chosen alternative by the called endpoint and returned in the OLC which accepts the proposed channel.

For proposed alternative channels from calling to called, the mediaChannel is chosen by the called endpoint. A unique fwdLCN is assigned to each proposal (alternative or not) by the calling endpoint.

In addition, all RTCP addresses proposed by the calling endpoint for a given sessionId must be the same, regardless of the direction of the logical channel.

Regards,

Dave Walker Mitel Corp.

Francois Audet wrote:

Hi,

Question on fastStart. When presenting different alternatives in the OpenLogicalChannel, the sessionID is the same for all, in order to distinguish between alternatives for the same session, instead of a proposal to open multiple media channels.

Is the same valid for the RTP/RTCP port numbers, and the logical channel numbers? Do they have to be the same for alternative proposals, or can they be different?

Any views?

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François Audet Tel:+1 408 565 5675 mailto:audet@NortelNetworks.com Nortel Networks Fax:+1 408 565 2375 http://www.NortelNetworks.com