[asterisk-dev] How to diagnose early media on a PRI
Pavel Troller
patrol at sinus.cz
Mon Aug 4 23:10:33 CDT 2014
> >>I'm not an expert on PRI, but maybe your telco is not passing on the early media to the caller.
>
> Yes, I believe that to be the case as well. My Telco has been...less than helpful. They are blaming the PBX, so I'm looking for a way to prove that asterisk is doing things correctly and shift the blame back on them.
>
Hi!
It's very probable that the PSTN switch is not passing audio, even you are sending the Progress IE in the Alerting message telling that the audio is available.
It is the default setting of most "mature" PSTN switches. For example, on EWSD, you would need to have the parameter PTHRUCON in your category to allow passing audio from the PBX without answer. Without it, the switch starts sending its own Ringback tone and totally ignores your media. With other switches, it's very similar.
However, I'm very surprised, why Asterisk sends Alerting at all ? There should be DISCONNECT with Clear Cause 17 (User Busy) and it can also contain the Progress IE with Inband Info now Available.
With regards,
Pavel
> -Justin
>
> ________________________________
> From: asterisk-dev-bounces at lists.digium.com [mailto:asterisk-dev-bounces at lists.digium.com] On Behalf Of Eric Wieling
> Sent: Monday, August 04, 2014 9:27 AM
> To: Asterisk Developers Mailing List
> Subject: Re: [asterisk-dev] How to diagnose early media on a PRI
>
> Why do you want to use early media instead of using OOB signaling by using Hangup(17)?
>
> I'm not an expert on PRI, but maybe your telco is not passing on the early media to the caller.
>
> From: asterisk-dev-bounces at lists.digium.com [mailto:asterisk-dev-bounces at lists.digium.com] On Behalf Of Justin Killen
> Sent: Monday, August 04, 2014 12:23 PM
> To: Asterisk Developers Mailing List
> Subject: Re: [asterisk-dev] How to diagnose early media on a PRI
>
> I have tried it, yes - the results are the same. When Busy() is called, the channel driver gets a message and opens the early media stream if it hasn't been opened already. I have the Q.931 entry for the alerting message for "Progress Description: Inband information or appropriate pattern now available. (8)":
>
> PRI Span: 8 > DL-DATA request
> PRI Span: 8 > Protocol Discriminator: Q.931 (8) len=9
> PRI Span: 8 > TEI=0 Call Ref: len= 2 (reference 1885/0x75D) (Sent to originator)
> PRI Span: 8 > Message Type: ALERTING (1)
> PRI Span: 8 TEI=0 Transmitting N(S)=11, window is open V(A)=10 K=7
> PRI Span: 8
> PRI Span: 8 > Protocol Discriminator: Q.931 (8) len=9
> PRI Span: 8 > TEI=0 Call Ref: len= 2 (reference 1885/0x75D) (Sent to originator)
> PRI Span: 8 > Message Type: ALERTING (1)
> PRI Span: 8 > [1e 02 81 88]
> PRI Span: 8 > Progress Indicator (len= 4) [ Ext: 1 Coding: CCITT (ITU) standard (0) 0: 0 Location: Private network serving the local user (1)
> PRI Span: 8 > Ext: 1 Progress Description: Inband information or appropriate pattern now available. (8) ]
>
>
> And it seems the Telco has received it on the other side:
>
> ------------Q931---------------------Q931 message-----------------------------
>
> 001 00001000 Protocol Discriminator : 8 - Q.931/I.145 user-ntwk call control msg
>
> ------------CRV----------------------Call Reference Value---------------------
>
> 002 xxxx0010 Length of CRV : 2 -
>
> ------------------------------------------------------------------------------
>
> 003 .0111000 Reference value : 56 -
>
> | 1....... Reference Flag : 1 - To call ref originator
>
> 004 11011110 Reference value : 222
>
> ------------------------------------------------------------------------------
>
> 005 x0000001 Message Type : 1 - Alert message
>
> ------------QPARMS-------------------Q931 Parameters--------------------------
>
> -------------------------------------Q931 Parameter---------------------------
>
> 006 x0011110 Parameter Name : 30 - Progress Indicator
>
> 007 00000010 Parameter Length : 2
>
> ------------PRGIND-------------------Progress Indicator-----------------------
>
> 008 ...x0001 Location : 1 - Private network serving the local user
>
> | .00..... Coding Std. : 0 - CCITT Standardized Coding
>
> | 1....... Extension Bit : 1 - Last Octet
>
> 009 .0001000 Progress Description : 8 - In-band info/an appr. pattern is now avlbl
>
> | 1....... Extension Bit : 1 - Last Octet
>
> ------------------------------------------------------------------------------
>
> This is (I assume) the opening of the early media stream. I'm just not sure where to go from there.
>
> -Justin
> ________________________________
> From: asterisk-dev-bounces at lists.digium.com<mailto:asterisk-dev-bounces at lists.digium.com> [mailto:asterisk-dev-bounces at lists.digium.com] On Behalf Of Eric Wieling
> Sent: Monday, August 04, 2014 8:59 AM
> To: Asterisk Developers Mailing List
> Subject: Re: [asterisk-dev] How to diagnose early media on a PRI
>
> Have you tried using Progress?
>
> From: asterisk-dev-bounces at lists.digium.com<mailto:asterisk-dev-bounces at lists.digium.com> [mailto:asterisk-dev-bounces at lists.digium.com] On Behalf Of Justin Killen
> Sent: Monday, August 04, 2014 11:58 AM
> To: Asterisk Developers Mailing List
> Subject: Re: [asterisk-dev] How to diagnose early media on a PRI
>
> Sorry for confusing the issue, I should have stripped out that line from the dialplan as well. Given just the busy() line:
>
> exten => 1005,n,Busy(20)
>
> The busy tone should(?) be generated from the PRI channel driver. This is the tone that the Telco is saying is being sent incorrectly. I've looked at the dahdi configs, and it is setup correctly to use US tones.
>
> -Justin
> ________________________________
> From: asterisk-dev-bounces at lists.digium.com<mailto:asterisk-dev-bounces at lists.digium.com> [mailto:asterisk-dev-bounces at lists.digium.com] On Behalf Of Eric Wieling
> Sent: Monday, August 04, 2014 8:33 AM
> To: Asterisk Developers Mailing List
> Subject: Re: [asterisk-dev] How to diagnose early media on a PRI
>
> Run Progress before the playtones. This is documented in https://wiki.asterisk.org/wiki/display/AST/Early+Media+and+the+Progress+Application
>
> --Eric
>
> ---
> Frequently Asked Questions
>
> Q1: How do a transfer a call using a Polycom phone?
> A1: While on a call press the Transfer button on the phone, wait for dialtone, dial the number you want to transfer to, wait for the person answer, tell them you are transferring a call, then press the Transfer button the phone a second time.
>
> Q2: I don't want to wait for the person answer when transferring a call.
> A2: Press the Transfer buton on the phone, the press the Blind softkey, the dial the extension you want to transfer the call to. The transfer should complete automatically. If it does not, you may need to press the Send softkey
>
> Q3: Where can I find more information on using Polycom phones?
> A3: Go to http://help.nyigc.net/ for documentation for Polycom phones.
>
> Q4: What is the best kept secret on the Internet?
> A4: That would be the InterGlobe Help Site, at http://help.nyigc.net/
>
> Q5: When calling my VMAX fax line I always get a busy signal.
> A5: You must call VMAX fax lines either from another VMAX fax line or from a non-VMAX voice line. If you call a VMAX fax line from a VMAX voice line you will always receive a busy signal.
>
>
> From: asterisk-dev-bounces at lists.digium.com<mailto:asterisk-dev-bounces at lists.digium.com> [mailto:asterisk-dev-bounces at lists.digium.com] On Behalf Of Justin Killen
> Sent: Monday, August 04, 2014 11:25 AM
> To: Asterisk Developers Mailing List
> Subject: [asterisk-dev] How to diagnose early media on a PRI
>
> I asked this on the users list a week and a half ago but haven't gotten any response. I'm hoping someone here with PRI/ISDN experience can help guide me in the right direction.
>
> I have a dialplan (freepbx) that plays a busy signal in-band when an extension is busy (before an Answer). Stripped down, it looks like this:
> exten => 1005,n,PlayTones(busy)
> exten => 1005,n,Busy(20)
> Note that there is no Answer() prior to this. Our trunk is a PRI.
> When I call into this extension from outside, I get about 25 seconds of ringing, followed by a hangup. Looking at the asterisk logs, 20 seconds of that delay is AFTER the PlayTones() function is invoked. I talked with our Telco about this, and they want to refer to in-band tones prior to answer as a media cut-through. The tech said that it is enabled on their end, and he did some test calls and got some ISDN trap logs. He is saying that the PBX is playing the ring-back tone instead of the busy tone, but I don't think that's the case (If I add an Answer() to the dialplan, I do in fact hear the busy tone).
> Is there anybody out there who has experience with reading/analyzing IDSN trap logs (Q931) that can help me narrow down where the issue is and how to fix it?
>
> Thanks,
> -Justin
>
> --
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