[OpenSIPS-Users] Stopping a T.38 reinvite with Opensips loose_route()

[Andreas Sikkema]

On 3/7/11 12:12 AM, Jeff Pyle wrote:
> As I said I've never seen a T.38 session start without a reinvite.  I
> have seen only unsupported codecs come in.  In a reinvite scenario, this
> will cause a 488.  On an initial INVITE, however, the Adtrans send a 415
> Unsupported media type.  I don't have enough experience with different
> types of gateways to know if this is normal behavior or not.

In situations where you *know* the call you're initiating is from a FAX
you can just start with offering T.38 and fall back when that fails. I
have heard from several vendors that this is advantageous in situations
where a G.711 to T.38 re-invite procedure takes too long and the fax
machines are not be able to synchronise and start the transfer.

I seem to remember AVM Fritz!Box ATAs doing this on the lower end of the
spectrum and heard the same from a number of "enterprise" hardware vendors

-- 
Andreas Sikkema