Re: Call for the ipdvb WG to adopt: draft-fairhurst-ipdvb-ule-ext-01.txt

[Gorry Fairhurst <gorry@erg.abdn.ac.uk>]

Thanks George,

Indeed, on this specific draft: MPEG-2 TS packets can indeed be directly 
mapped in a S2 BBframe, without the use of extra overhead - as you say, 
but the aim was (as you hinted) to provide a way of sending small 
ammounts of SI-Data over a totally packet-based (IP) link-layer, so that 
a future system would not require a separate ISI for the TS, and
could for example receive its signalling in-band with the data.

On the other research areas you identify, relating to all-IP based 
solutions, these seem like good potential areas for future work and 
important standardisation - and would be good to include in the Charter 
debate for future work in this group - I would be interested to know if 
other people have comments on your list?

Thanks,

Gorry

---

Dear Gorry,

thanks for your initiative.
I read your draft carefully and found it very interesting.
However, I have the feeling that MPEG-2 TS is gradually abandoned and we 
are paving towards an "all-IP" environment. The introduction of "generic 
stream" shows exactly this tendency, and I believe that the same 
philosophy is to be followed in the 2nd generation terrestrial specs 
also (DVB-T2). Surely, providing a support for TS packets encapsulation 
within GSE or ULE might provide a backwards-compatibility, but IMHO it 
is of questionable usability. MPEG-2 TS packets can be directly mapped 
in a S2 BBframe, without the use of extra overhead.

At NCSR "Demokritos", we have a strong experience in IP/DVB and are 
currently leading a European research activity which is to investigate 
DVB-T2. In the latter, our team is devoted to research regarding 
baseband formatting and upper-layer issues.

My proposal: we can go on with your draft, since it strengthens the role 
of GSE and ULE, making them more flexible. Indeed, the feature of 
grouping data belonging to the same NPA is quite attractive. But I 
believe it is also important to look into how the ipdvb WG can benefit 
from the advance of next-generation terrestrial standards. Looking 
towards the "shutoff" of the MPEG-2 TS, possible issues for research 
could be:

- the full migration of the MPEG signalling (PSI) to IP/GSE level
- the transfer of the DVB-H Time Slicing feature in IP/GSE level
- the transfer of the transport-layer FEC (MPE-FEC) in IP/GSE level.
and generally any issue which may stem from the use of Next-gen DVB as a 
"transmission system for broadcasting IP datagrams"

I would be more than willing to participate in any activity covering 
such issues.

Thanks and best regards to all,

George

---------------
Dr. Georgios J. Gardikis
Associate Researcher
Digital Telecommunications Lab
NCSR "Demokritos", Institute of Informatics and Telecommunications
Ag.Paraskevi, Athens, Greece
Tel: +30 210 6503108
Fax: +30 210 6532175
Web: http://aias.iit.demokritos.gr/~gardikis
Email: gardikis@iit.demokritos.gr





O/H Gorry Fairhurst έγραψε:

As WG Chair, I request the ipdvb list to consider whether the WG is 
ready to adopt the following individual ID (Internet Draft) as a working 
group ID, with an intention to develop this into a RFC.

This particular draft was introduced to support a standard in 
preparation by the DVB Forum. The aim is to make the 2nd Generation 
Physical Layer present an interface via the Generic Stream Encapsulation 
that is consistent with ULE (e.g. uses the IANA registry), so that both 
can benefit from common extension modules: header compression, etc 
(should these be defined).

PLEASE DO read the draft below and offer email comments on the 
suitability or progression to an RFC and the technical content. ALL 
comments are welcome. Email received before the 25th January 2007 will 
be used to inform the decision about whether to make this a WG Draft.

WG documents should no longer be regarded as the property of the 
individuals who originally authored them - the working group as a whole 
must decide how they are shaped, and to see the document to a successful 
conclusion. If adopted, the Internet Draft will be renamed to start with 
the filename draft-ietf-ipdvb..., and will be listed on the IETF web 
page for this WG.


Best wishes,

Gorry Fairhurst
(ipdvb WG Chair)


----


Title : Extension Formats for Unidirectional Link Encapsulation (ULE) 
and the Generic Stream Encapsulation (GSE)
Author(s) : B. Collini-Nocker, G. Fairhurst
Filename : draft-fairhurst-ipdvb-ule-ext-01.txt
Date : 2007-1-11

This document describes a set of Extension Headers for the
Unidirectional Lightweight Encapsulation (ULE). The Extension Header
formats defined in this document provide new extensions that are
common extensions to both ULE and the Generic Stream Encapsulation
(GSE) defined by the second generation framing structure DVB-S2
standard (Channel coding and modulation systems for Broadcasting,
Interactive Services, News Gathering and other broadband satellite
applications).

A URL for this Internet-Draft is:
http://www.ietf.org/internet-drafts/draft-fairhurst-ipdvb-ule-ext-01.txt