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Re: [AVT] gen-art review of draft-ietf-avt-rtp-atrac-family-16.txt




If we assume that the smallest MTU is 576, would anything need to be changed?


On Aug 18, 2008, at 20:31 , actech wrote:

----------------------------------------------------
> > 5.3.1 Usage of ATRAC Header Section
> >
> >  >    Fragment Number (FrgNo): 3 bits
> > > In the event of data fragmentation, this value is one for the
> >  >    first packet, and increases sequentially for the remaining
> >  >    fragmented data packets. This value SHOULD be zero for an
> >  >    unfragmented frame.
> >
> > Earlier it was said: "The ATRAC codec can handle very large frames. As > > most IP networks have significantly smaller MTU sizes than the frame
> > sizes ATRAC can handle ...".  If there can be such a significant
> > difference -- and if you want to allow for larger frames in the future > > -- is there special handling for when this 3-bit counter rolls over
> > (more than 7 fragments)?  If not, at least mention that you do not
> > expect it to roll over -- or that you expect the receiver to be able to
> > handle rollovers.

In ATRAC specification, it is described that supported bit-rate is
up to 1.4Mbps. It corresponds to approximately 7500bytes/frame.
So 3-bit counter is sufficient for expressioning Fragment Number,
as far as the MTU size is 1500bytes.

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