RE: [rohc] Liaison towards 3GPP

["Casati, Alessio (Alessio)" <acasati@lucent.com>]

> I have also seen these not yet concretized proposals for header
> stripping and I don't think that they are a preferred way. 
> 
Tdoc 2-00-771 from Nokia (sorry for introducing company related
things here, which I hate to do, but this is how SMG2 works) is a good
document, although not yet finalized and approved, for instance.
Also There are some merits in handling RTP play out at the RNC
for R'99 CS backward compatibility.

> They violate
> the end-to-end integrity of IP. To me it seems like these proposals aim
> at "eating the cake and still try to keep it".
> 
For the sake of truth, they don't violate IP integrity, 
but RTP integrity (not to mislead anybody, this is not WAP
based ;).

>  Furthermore, I seriously doubts that there is any large
> gain in capacity having this kind of algorithms. The proposals I've seen
> involves sending some header related information over the air-interface,
> hence they will create some overhead. Since there are no actual detailed
> proposals on header stripping (to my knowledge) it is not possible to
> estimate the overhead, however, it is not unlike that it would be some
> 0.x of a byte overhead in average per packet.
> 
I would say that once the bearer is set up, maybe that X
is very close to 0.

> Given the propsals for header compression in ROHC wg today, the
> difference in efficiency will not be large. ROCCO for instance is
> currently able to compress the header down to an average of appr. 1
> byte. 
> 
1 byte out of 20 is 5 %.  

Spectrum license B in UK auction is now valued around  $6 billions
5% is roughly valued $300 M even 30% of that is still $100 M.  That's enough
to start looking at the merits of header stripping.

> I don't expect the final scheme to be any less efficient. Hence,
> with header compression the efficiency will be only slightly smaller,
> but you have the very desirable property of IP end to end. 
> 
when trading IP end to end for voice services and $300 M (or $100 M) a
carrier may like the latter. This however does not mean we don't need
the ROCH stuff. People just must be informed and be aware of the
context they are working in (I assume not everybody here has visibility
on everything, and I would like to be informed about what I can't see
myself)


alessio