Skype for Business 2015 Standard Server with TCP Sip trunk NOT working (stilling using TLS )

Question

Hi there,

I'm trying to use skype call into Asterisk (PBX). I had Skype for Business 2015 Standard Server installed with collocated mediation server enabled, mediation server configuration as follows:

Also, I set up a PTSN gateway as follows:

and a SIP trunk:
(picture upload failed)

Trunk name: 172.31.45.64-5060
PTSN gateway: 172.31.45.64
Listening port: 5060
SIP Transport: TCP
Mediation Server: sfb.xxxx
Mediation Server port : 5060

when I trying to use Skype for Business Client call Asterisk, let's say, call 5464604320:

client responsed with 'No response from server' .

After I check SFB logs , I found following output :

Severity: error  
Text: Failed to complete outbound connection  
Peer-IP: 172.31.32.14:5070  
Connection-ID: 0x1C503  
Transport: TLS  
Result-Code: 0x8007274d  
Data: ip-address="172.31.32.14";peer-type="InternalServer";winsock-code="10061";winsock-info="The peer actively refused the connection attempt"  
$$end_record  

Severity: error  
Text: Message was not sent because the connection was closed  
SIP-Start-Line: INVITE sip:5464604320@172.31.45.64:5070;user=phone;maddr=sfb.xxxxx SIP/2.0  
SIP-Call-ID: 440f6a53e6fb44e4a23cd53643a6dae3  
SIP-CSeq: 1 INVITE  
Peer: 172.31.32.14:5070  

......  

TL_INFO(TF_PROTOCOL) [sfb\sfb]162C.2FD0::07/27/2021-12:05:30.871.0042EE20 (OutboundRouting,OutboundRoutingDispatcher.OnResponse:outboundroutingdispatcher.cs(604)) [2753578010]Received status code 504 for request sip:5464604320@172.31.45.64:5070;user=phone;maddr=sfb.xxxxxx  
TL_INFO(TF_COMPONENT) [sfb\sfb]162C.2FD0::07/27/2021-12:05:30.871.0042EE21 (OutboundRouting,OutboundGateway.IncrementDownCounter:gateway.cs(233)) (000000000164C597)Processing response from Target 172.31.45.64-5060 [Response=504]  
TL_INFO(TF_PROTOCOL) [sfb\sfb]162C.2FD0::07/27/2021-12:05:30.871.0042EE22 (OutboundRouting,OutboundRoutingDispatcher.ReRouteRequest:outboundroutingdispatcher.cs(2998)) [2753578010]Target [172.31.45.64-5060] failure - reason [504 Server time-out]  

in the log above, 172.31.45.64 is my asterisk server with TCP enabled on 5060. 172.31.32.14 is SFB with collocated mediation server.

it looks like the problem is SFB is using TLS for inviting Asterisk: INVITE sip:5464604320@172.31.45.64:5070

I can also get and error event in Event Viewer:

An attempt to route to a gateway failed.  
  
Could not route to Gateway 172.31.45.64-5060, the attempt failed with response code: 504 Server time-out (CallID: e2a1902e099f4f1f871744c28fb5ef6f).  
Failure occurrences: 1, since 2021/7/27 12:44:30.  
Cause: A gateway failed to respond to a request within allotted time or was unable to route the request due to some error.  
Resolution:  
Check whether the specified gateway is up and is properly configured.  

the port used for invite should be 5060 as trunk settings showed. I don't know why it still using port 5070. Also, the transport should be TCP rather than TLS.

Anybody know how to change that port number (from 5070 to 5060 with TCP)?

Thanks in advance.

Answer 1

Hi @JimmyYang-MSFT , thanks for your help.

We finally found the problem.

The **Collocated Mediation Server is NOT started. ** In the SFB Control Panel, it's status always been Retrieving... .

We tried many ways try to start the collocated mediation server, but failed, also, there is no logs in Event Viewer pointed to Mediation Server.

The solution is, installing a stand-alone mediation server on another machine, adding it to mediation server pool for use.

That solved my problem.