[asterisk-dev] extend IAX2 IE proposal

[Derek Smithies]

Hi,
On Mon, 11 Dec 2006, Russell Bryant wrote:
> 
> I was thinking of this exact same idea.  Another reason for choosing this over
> the previous proposal is that we only take up a single IE identifier, as
> opposed to 16.  This method takes up an extra byte to store the segment
> number, but given that you had to segment the IE in the first place, you're
> already sending a significant enough amount of information where the extra
> byte does not make much of a difference.
> 
> Unless there is any opposition, this proposal gets my vote.

Well no..
I am not happy with this. Yes yes, it will work to a size of 4096 bytes or 
some such size. But what happens if someone wants 20K bytes? Should we 
not, at this time, think about future requirements? I am thinking of when 
iax2 is used as an alternative to MSN, and people are doing file transfers 
over iax2. Or other such large transfers.
 
The proposal above is, in my view flawed - it does not go large enough.
Worse, there has been no discussion on how it will go on a moderately 
lossy link. The calculation I put forward a while ago was based on 100 K 
bytes, and 0.1% loss. Now, on a 1 % lossy link, what happens? audio 
quality is poor, and they send out a large packet. The packet does not 
make it through, and all full frames are held up, waiting for this super 
large packet to go out. Does that mean the link is frozen in an up state, 
and one cannot send the hangup message?

Sure, in some countries of the world with ethernet links to each house, 1% 
is ridiculously high. However, for many others, 1% does happen. 

Derek.
-- 
Derek Smithies Ph.D.
IndraNet Technologies Ltd.
Email: derek at indranet.co.nz
ph +64 3 365 6485
Web: http://www.indranet-technologies.com/