[asterisk-dev] extend IAX2 IE proposal

[Tim Panton]

On 3 Dec 2006, at 21:11, Derek Smithies wrote:

> Hi,
> On Sun, 3 Dec 2006, Markku Korpi wrote:
>> Derek Smithies wrote:
>>> On Wed, 29 Nov 2006, Kevin P. Fleming wrote:
>>>> Di-Shi Sun wrote:>
>>
>> The third option could be to add a segmentation procedure in a  
>> similar way as
>> they are used e.g. in SS7 ISUP and Q.931. In this case we would  
>> need to select
>> a message coding scheme that would cause an old client/peer to  
>> throw away the
>> segment message, but proceed with the non-segmented content.
>>
> Are you suggesting to segment a large block of data into 250 byte  
> (say)
> chunks, with each chunk in a separate IE? Place a header byte (or  
> two) as
> the first element of the data field stating where this chunk is in the
> large block of data ?

But Kevin's point still applies, IAX doesn't support multiple  
instances of the same
IE type in a message. So to implement your scheme you need to  
allocate new
IE types called ExtendedMessage0 through to ExtendedMessage32 (or  
whatever)
- which then obviates the the need for the second 'sequence' byte in  
the data.

Anyhow, I can't help feeling this is the wrong way to tackle the problem
(admittedly we have not had the actual problem described, just a  
possible
solution).

Depending on what (exactly) the OP is trying to do, using one of the
existing frame types seems like a better plan than using an IE,
perhaps a 'pseudo' image or provisioning frame ?


Tim Panton

www.mexuar.net
www.westhawk.co.uk/