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wfx

Blind Transfer REFER Issue

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wfx    0

I am working on evaluating the Vodia PBX as a gateway to a legacy Microsoft Speech Server (MSS) based IVR application. I am using the Vodia Free edition and I have the following setup:

  • ITSP -> Vodia PBX -> MSS IVR
  • ITSP and MSS are both configured as trunks.
  • Extension created that redirects calls via dial plan to MSS,
  • ITSP trunk is configured to send all calls to extension for MSS.

I am able to receive calls from the PSTN via the ITSP to the MSS IVR with no issue, but I am unable to blind transfer a call (REFER) from MSS back to the ITSP. When the MSS sends the REFER to the Vodia PBX it logs the following:

[5] 0:01:15.003    APP:    Redirecting call to 1234567890
[5] 0:01:15.003    APP:    REFER without a valid extension is not accepted on trunk 2 0
[8] 0:01:15.003    MEDI:    Port 60: state code from 200 to 486
[8] 0:01:15.003    MEDI:    Port 60: Send hangup with reason bye

I have read this thread regarding a similar issue:

I have made changes to my configuration to enable the trunks as Global and allow REFER, but always received the same response from the Vodia PBX. The post as well as the https://vodia.com/doc/trunk_settings Trunk Settings help document make reference to a setting called "Assume that call comes from user", but I do not see this in my Vodia version nor does my version look anything like the screenshot in the Trunk Setting help doc.

Anyone have any thoughts?

wfx

 

 

 

 

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Support    0

Hi,

 

Could you please try this and let us know:-

On the trunk settings you set "Yes" under "Inter-Office Trunk --> Trunk may terminate calls for remote systems" and then set the dial plan to "Dial plan for outbound calls"

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wfx    0

Support,

Thanks for the quick response! Made your suggested modification to the trunk, but no change, same result in the logs - "REFER without a valid extension is not accepted".

Something else of note, when the Vodia receives the REFER request from the MSS IVR it determines it should not accept it and then returns a BYE back to the MSS IVR, but it never sends a BYE to the ITSP leg of the call. This results in the original call from the PSTN still being open with dead air and requires the caller to hangup to generate a BYE from the ITSP to the Vodia. It's almost like the Vodia is treating the REFER as a new call and not part of the existing one it is bridging between the MSS and ITSP.

What I am really looking for is the Vodia to just pass the REFER back to the ITSP and not act on it.

wfx

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Vodia PBX    0

You must enable "Accept redirect" for that trunk. The MS server uses those redirects; by default they are not permitted. There are a couple of posts for this topic already on the forum and also in the Internet. Try searching for pbxnsip and microsoft speech server and also microsoft exchange and sip, this will show you a couple of more results on the topic.

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wfx    0

Vodia PBX,

FYI - "Accept redirect" is enabled. Note, redirects are not the issue here, blind transfer (REFER) is the issue. I believe you are referring to the Speech Server known issue of sending 302 Redirects on the initial INVITE to steer the incoming call to a new random high TCP port, which is working fine, the call is up and working normally. My problem is that my IVR has the option to transfer to a live operator and if the caller chooses that option the IVR app initiates a blind transfer via SIP REFER to signal back to the ITSP to transfer the call. When the Vodia PBX receives this message it refuses to act on it and logs the following:

REFER without a valid extension is not accepted on trunk 2 0

I need to figure out how to configure Vodia to allow the REFER through from a "Sip Gateway" trunk. Any thoughts?

wfx

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Vodia PBX    0

Ok if you have already enabled the accept redirect you should be half way there. The PBX now needs to know what dial plan to apply (who should pay for the call). What you can try here is to assign an extension the caller-ID that the speech server is using (as addition alias name, e.g. "40 +16171231234"), even if just for try. If the SIP INVITE shows in the From field a number that is found in the domain, it will use that extension for the dial plan and then the call should go through. If that is working at least we should know what knob to turn here.

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wfx    0

Vodia PBX,

According to the help document for extensions the Alias should be entered into the Account Number field:

Quote

Number: This field takes an extension number and/or alias, i.e., a DID number. When entering DIDs as aliases to an extension number, use the following syntax: 505/9781234567/9781234567. To create multiple accounts at the same time, use a space between them: 505 506 507

My extension # for forwarding to MSS is 888 and the from DID on the REFER from MSS say is 1234567890, so I changed the "Account number(s)" field from just "888" to "888/1234567890" however once I do that the inbound call can no longer find the 888 extension , returns a 404 to the caller and this written to the log:

[8] 11:25:50.725    TRUN:    Send call to extension ERE returned 888
[8] 11:25:50.725    TRUN:    User 888 not found in domain 10.10.10.6
[3] 11:25:50.725    APP:    Port 32: No destination found for the call

If I return the "Account number(s)" field to "888" it works as normal and forwards the incoming call to MSS.

Since the help document seems to be written for an older version of Vodia, is the syntax for specifying the alias in the help document correct?

wfx

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