Re: MPE Question

[Bernhard Collini-Nocker <bnocker@cosy.sbg.ac.at>]

Dear Siva,

you are right in that I had understood your question different.

Generally Sections do allow for numbering that is, one can put a payload 
(for example a DSM-CC object) into a number of Sections and with 
section_number and last_section_number the reassebler knows what to do. 
MPE uses this Section mechanism, so multiple Section operations should 
be possible. Actually I have never tested whether MPE decapsulators do 
support this in real, in principle they should (again the DVB 
databroadacst standard does not say too much, if anything, about it) but 
in DSM-CC Obejct carousels is a very usual mode of operation.

Siva Veerepalli wrote:
> Thanks for the response Bernhard, but I am a bit
> confused about the answer. Please see my question
> below:
>
> --- Bernhard Collini-Nocker <bnocker@cosy.sbg.ac.at>
> wrote:
>
> > Siva Veerepalli wrote:
[...]
> I understand that two MPE sections could probably
> start in the same TS packet (I guess that is what you
> mean by section packing).

Yes.

> My original questions was, what is the usual practice
> with regards to fragmenting an IP datagram over
> multiple MPE sections (irrespective of how these
> sections are transported in TS packets)? The DVB-H
> (data broadcast standard) allows for this, however,
> the IPDC interim specification requires that one
> datagram be encapsulated entirely in one mpe section
> i.e., no datagram fragmentation over multiple MPE
> sections.

Now the confusion starts when one introduces the wording of "over 
multiple MPE sections", because there is no such thing as a MPE section 
fragmentation.
I will have to read the DVB-H standard again in order to find out what 
it really says. I guess the only real issues the DVB-H wrt to IP is 
addressing is the necessity of a IP datagram encapsulated in MPE is to 
support time slicing (ie a burst transmission of the resulting TS 
packets to allow for power saving) and MPE-FEC (adding redundant code to 
allow for reconstruction). In that case I woould assume that it is very 
reasonable (especially with legacy equipment) to avoid all potential 
interpretations of MPE wrt multiple section operation and section packing.

> thanks,
> Siva
[...]

Yor are very welcome,
and I hope I got THE expected answer closer,
Bernhard