[asterisk-dev] New frame type for IAX: AST_FRAME_RAW ?

[Tim Panton]

On 7 Feb 2007, at 08:31, Roger Schreiter wrote:

> Tilghman Lesher schrieb:
>> ...
>>> If it is a propriatry protocol by a certain ISDN software,
>>> like the formerly common (before internet was widely available)
>>> file transfer software Leonardo, just reject data tranfser?
>> Correct.
>
>
> Hi,
>
> ok, I got your thoughts.
>
> You recommend not you use IAX in order to extract
> one ISDN channel from a PRI card and forward it to
> another computer to create a virtual "/dev/ttyIx".
>
> I should look for another transport. Is it right?
>
>
> Ok, will think about it.
> Thanks for telling your considerations!


If you did go down this route, you need to remember that
IAX is over UDP, hence lossy, it does have retry mechanisms,
but they only really apply to 'full' frames which are used to carry
commands. You would need to ensure your ISDN data was all
in full frames, not in miniframes, or you would need to add
a retry mechanism on top....

Tilghman is right, IAX isn't the right protocol for this - at least
at the general level. As for the G4 fax, you would do better to do the
decoding close to the PSTN and pass tiffs around instead.

You might want to look at Plan9 and the 9p protocol to
see this kind of thing taken to extremes.
In Plan9 you could export the /dev file system over 9p
to a 'client' computer and the client could read and write
the device as if it were it's own.

They took this to absurd lengths by exporting the /dev/framebuffer
from your desktop to the compute server so it could draw
on your screen !



>
>
> Roger.
>
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Tim Panton

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