[Rmt] Re: [MMUSIC] FW: New Version Notification - draft-mehta-rmt-flute-sdp-04.txt

[Colin Perkins <csp at csperkins.org>]

Hi,

On 25 Nov 2005, at 12:49, Magnus Westerlund wrote:
...
> > Layering:
> > The layering with slash notation was our first consideration for
> > describing multiple channels some time ago (check out the  
> > discussion on
> > differentiating channels in the I-D). Using slash notation for one  
> > but
> > not the other is allowed (again check the I-D for reasons). However,
> > limiting all FLUTE sessions to only using conecutive numbers  
> > (addresses
> > for multicast; ports for unicast) is unecessary and potentailly  
> > harmful
> > as we do not yet a have a comprehensive set fo RMT CC RFCs for each
> > scheme which has been dicsussed. i.e. we need a means to group  
> > different
> > m-lines together: appearing in the same SDP without group:CS for  
> > single
> > FLUTE session SDPs; have a mid:# belonging to the same group:CS as  
> > other
> > media is for multiple FLUTE session SDPs. Use of port numbers to  
> > differentiate channels (with the same IP
> > destination/group address) is only useful where some other
> > application-based congestion control is introduced; indeed it is
> > recommended only for unicast applications. Differentiation of  
> > channels
> > based on IP destination/group address is appropriate for multicast
> > sessions with RMT congestion control. Note, the RMT family uses
> > layers/channels principally for congestion control. Using them for  
> > FEC
> > is allowed but if it messes with congestion control deployment on the
> > public Internet can not be assumed feasible.
>
> I think that using CS instead of the layering mechanism is the  
> right choice. However I think one should require the usage of CS  
> for all cases where a FLUTE session contains more than a single  
> channel. That way we are consistent with SDP usage.

I agree - my main concern with this draft is the implicit grouping of  
channels ("m=" lines) into a single session, unless otherwise  
signalled. I strongly prefer a solution where separate "m=" lines  
denote separate FLUTE sessions, unless the grouping framework is used.

Colin

_______________________________________________
Rmt mailing list
Rmt at ietf.org
https://www1.ietf.org/mailman/listinfo/rmt