asterisk users - Apr 2005 - IAX blind transfers

Good Evening,  

 

Just a quick question to ask if blind transfers (via #) are possible?  I
have an IAX2 connection to my VOIP provider. In my dial plan I sometimes
forward an incoming call back out on IAX, but when this happens I seem
to lose the ability to transfer the call.  If the incoming call uses
SIP, or the destination uses SIP, transfer works.  I've noticed that in
the Asterisk CLI I get message saying "Attempting Native Bridge", but
nothing more to indicate whether this failed or succeeded.  I have tried
notransfers=yes and notransfers=no in my iax.conf, but this doesn't seem
to make a difference, as best I can tell asterisk is staying in the call
though, so I'm guessing blind transfers aren't possible?

 

Paul

 

 

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On Thu, 14 Apr 2005, Paul Seymour wrote:
> Just a quick question to ask if blind transfers (via #) are possible?  I
> have an IAX2 connection to my VOIP provider. In my dial plan I sometimes
> forward an incoming call back out on IAX, but when this happens I seem
> to lose the ability to transfer the call.  If the incoming call uses
> SIP, or the destination uses SIP, transfer works.  I've noticed that in
> the Asterisk CLI I get message saying "Attempting Native Bridge",
but
> nothing more to indicate whether this failed or succeeded.  I have tried
> notransfers=yes and notransfers=no in my iax.conf, but this doesn't
seem
> to make a difference, as best I can tell asterisk is staying in the call
> though, so I'm guessing blind transfers aren't possible?
If the Asterisk box IS doing IAX native bridging, then the # won't be seen 
on that box.

Native bridging is a different thing than transfering.  When an Asterisk 
box "transfers" the call it actual gets the two remote IAX peers to
rather
talk directly and sees nothing more of the call (in an IAX trace you'll 
see TXREQ (transfer request) frames and similar).

"notransfer" is about enabling and disabling this feature.

Native bridging is just where chan_iax2.c uses an optimised "quick
copy"
function to pass frames between the input and output iax connections.

Native bridging will be done whenever two IAX channels are bridged 
together and both use the same codec etc.

There's no config file option to enable or disable it.

If you don't want native bridging, you need to disable it in chan_iax2.c 
by undefining BRIDGE_OPTIMIZATION.  If you do that, then your box will 
probably hear and act on the # transfer request.

Regards,
Steve

On Thu, 14 Apr 2005, Paul Seymour wrote:
> 
> > Just a quick question to ask if blind transfers (via #) are
possible?  I
> > have an IAX2 connection to my VOIP provider. In my dial plan I
sometimes
> > forward an incoming call back out on IAX, but when this happens I
seem
> > to lose the ability to transfer the call.  If the incoming call uses
> > SIP, or the destination uses SIP, transfer works.  I've noticed
that
in
> > the Asterisk CLI I get message saying "Attempting Native
Bridge",
but
> > nothing more to indicate whether this failed or succeeded.  I have
tried
> > notransfers=yes and notransfers=no in my iax.conf, but this
doesn't
seem
> > to make a difference, as best I can tell asterisk is staying in the
call
> > though, so I'm guessing blind transfers aren't possible?
> 
> If the Asterisk box IS doing IAX native bridging, then the # won't be
seen
> on that box.
> 
> Native bridging is a different thing than transfering.  When an
Asterisk
> box "transfers" the call it actual gets the two remote IAX peers
to
rather
> talk directly and sees nothing more of the call (in an IAX trace
you'll
> see TXREQ (transfer request) frames and similar).
> 
> "notransfer" is about enabling and disabling this feature.
> 
> Native bridging is just where chan_iax2.c uses an optimised "quick
copy"
> function to pass frames between the input and output iax connections.
> 
> Native bridging will be done whenever two IAX channels are bridged
> together and both use the same codec etc.
> 
> There's no config file option to enable or disable it.
> 
> If you don't want native bridging, you need to disable it in
chan_iax2.c
> by undefining BRIDGE_OPTIMIZATION.  If you do that, then your box will
> probably hear and act on the # transfer request.
> 
Thanks Steve, have done as you suggested and it works perfectly.  Would
this be considered a bug since the T or t directive in the dial plan
probably should preclude native bridging if the end result is to prevent
a transfer?