[cisco-voip] Early media

Thu Apr 14 15:16:46 EDT 2005

Hi Bryan,

Yes the progress indicator contains the value of 8 and is actually being
sent in the progress message. As you said there is not much one can do.
Answering the call would ruin my accounitng and I don't want to do that. I
have to tackle it from the Central Office end. I tested with a two PRAs; one
from Ericsson switch and another from a Siemens EWSD switch and they both
behave in the same manner, ie they do not cut-thorugh the early media when
this is coming from the subscriber side.  Maybe some sort of security measure not to allow users playing announcements to their callers for free!!!!!!!!

Thanks again,

Carmelo

----- Original Message -----
From: "Bryan Deaver" <bdeaver at cisco.com>
To: "Karl Smith" <sipware at yahoo.co.uk>
Sent: Wednesday, April 13, 2005 5:11 PM
Subject: Re: [cisco-voip] Early media

> The last thing to check is that the isdn progress/alert being sent from
the
> GW does contain a PI of 8; it should if the audio is being cut through by
> the GW.  If this all checks out, then there is not much you can do on the
> GW.  You could try something like doing a 2-step dialing at the GW so that
> the call actually connects on the ISDN side, then sends out the SIP
invite.
> I simple tcl script could force this but it ends up screwing up any
> accounting you may have and could lead to other potential issues.
>
> Bryan
>
>
>
>
>
> From: Karl Smith <sipware at yahoo.co.uk>
> Date: Wed, 13 Apr 2005 09:17:29 +0100 (BST)
> To: <cisco-voip at puck.nether.net>
> Subject: [cisco-voip] Early media
>
> Hi Bryan,
>
> thanks for your suggestions. This morning I was just thinking exactly on
the
> same lines. I have in fact performed the suggested debugs and confirmed
that
> the gateway is infact cutting through the early media; it is the central
> office which is not switching it through to the caller. I have also traced
> the SS7 signalling (i have access to the CO signalling system) and the ACM
> lacks the optional parameter :
>
> 'Inband information: inband info or pattern now available'
>
> Furthermore, looking at Q931 rec, it appears that not all ISDN networks
> supports the transmission of early media originating from the ISDN
> subscriber side:
>
> K.2 Procedures
> As a network option, completion of the transmission path prior to receipt
of
> a call acceptance
> indication may be provided in one of three ways:
> a) on completion of successful channel negotiation at the destination
> interface; or
> b) on receipt of a message containing an indication that in-band
information
> is being provided;
> or
> c) not at all, i.e. this option is not supported by the network.
>
> Thanks a lot for your help.
>
> Best regards,
>
> Carmelo
>
>
>
>
>
>
> It should be cut through dependent on the sip progress message we receive.
> You might try 'progress setup enable 3' on the voip sip dial-peer as well.
>
> Can you make a single test call with the following debug enabled so we can
> see what is happening:
>     - debug isdn q931
>     - debug ccsip message
>     - debug voip ccapi inout
> Make sure that you have disabling console logging to minimize the impact
of
> enabling the debugs.
>
> You can also check the output of 'show call active voice brief' while the
> call is in alerting stage.  You should see on the ip call leg side the rx
> packet count incrementing and on the telephony call leg side you should be
> able to see the 'out' dbm level fluctuate when you do multiple iterations
of
> the command.  If you see what appears to be some audio on the telephony
call
> leg (meaning that you see the 'out' level at something than
around -79dbm),
> t! hen it sounds like the audio is being cut through at the gateway but
> somewhere in the isdn cloud it is not being cut through.
>
> Bryan
>
>
> From: Karl Smith <sipware at yahoo.co.uk>
> Date: Tue, 12 Apr 2005 15:20:11 +0100 (BST)
> To: <cisco-voip at puck.nether.net>
> Subject: [cisco-voip] Early media
>
> Hi,
>
> thanks a lot for your help, but unfortunately the rtp send-recv did not
> solve the problem. I have also upgraded the IOS but still no success.
>
> Any other ideas??
>
> Regards,
>
> Carmelo
>
>
>
>
>
>
> From: "Teodor Georgiev" <tgeorgiev at is-bg.net>
> To: <cisco-voip at puck.nether.net>
> Sent: Tuesday, April 12, 2005 15:42
> Subject: Re: [cisco-voip] Early media
>
> > >
> > voice rtp send-recv
> >
> > issue that command in global configuration mode. It shall solve your
problem.
> > The issue you have described below is an usual behaviour - the reverse
> > "bearer" path won't be opened until a CONNECT message is received.
> >
> >
> >
> > On Tuesday 12 April 2005 11:40, Karl Smith wrote:
> > > Hi,
> > >
> > > I am using a 2610 as a sip to isdn gateway. It appears that there is
an
> > > issue with early media. When the gateway receives rtp in early media
on the
> > > ip side it does not switch it through on the isdn bearer channel.
Hence if
> > > any announcements or tones are provided on a media server just after
the
> > > 183 session progress and before the 200 OK, these cannot be heard on
the
> > > ISDN side.
> > >
> > > This problem does not exist in the reverse direction; i.e. if an
> > > anno! uncement is available on th! e isdn side before the connect
message,
> the
> > > gateway will swith it on an rtp stream and sends it to the ua.
> > >
> > > The IOS image that I am using is the c2600-is3x-mz.123-6b.bin
> > >
> > > Does any one knows whether this problem was resolved in more recent
> > > releases? If yes, any ideas which release?
> > >
> > > Thanks and regards,
> > >
> > > Carmelo
> > >
> > >
> > >
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