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U1981 - Transfer to mobile phone issue

Publication Date:  2018-03-16 Views:  80 Downloads:  1
Issue Description

Customer reported an issue when trying to transfer to a mobile phone. The scenario is as follows:

 

Extension A: 1473

Extension B: 2684

Extension C - External mobile phone - 628822118

 

When extension A places a call to extension B and afterwards extension A tries to transfer the call to number C  (external mobile phone); extension A can not talk with number C and the reorder tone appears


Handling Process

In order to address tthe reported issue we have performed the following steps;

1. checked the configuration file of U1981/ gathered the data.bin file

2. Checked the configuration of the involved SIP users.

3. Extracted the debug log and signaling trace using LMT after reproducing the issue

4. After analyzing the debug log provided we have found the following:

 - There is an Astra IP phone involved that does not support the G722 codec.





From the below REFER message used to teransfer the call in SIP signaling the request is accepted with a 202 Accepted message:

 

sCallMsg:[Y], Direction:[10.71.1.138--->172.16.239.202]

REFER sip:0628822118@172.16.239.202:5060;user=phone SIP/2.0

Via: SIP/2.0/UDP 10.71.1.138:5060;branch=z9hG4bKej69zzmv5j3evj556yye56w8w

Call-ID: uxevsju5jmgsyg3gm6v835svj8u3gsez@10.71.1.138

From: "2495"<sip:2495@172.16.239.202>;tag=j6gezzx8

To: <sip:0628822118@172.16.239.202;user=phone>;tag=vwmm54fx

CSeq: 4 REFER

Contact: <sip:2495@10.71.1.138:5060;transport=udp>

Refer-To: <sip:2207@172.16.239.202;user=phone?Replaces=36m6yuw339jsj9eesj33z8sxe53vxj3z%4010.71.1.138%3Bto-tag%3Dvmlawayn%3Bfrom-tag%3Devgyy5wz>

Referred-By: <sip:2495@172.16.239.202>

Max-Forwards: 70

User-Agent: Huawei eSpace 7910 V200R003C00

Content-Length: 0

 

 

IsCallMsg:[Y], Direction:[172.16.239.202--->10.71.1.138]

SIP/2.0 202 Accepted

Via: SIP/2.0/UDP 10.71.1.138:5060;branch=z9hG4bKej69zzmv5j3evj556yye56w8w

Call-ID: uxevsju5jmgsyg3gm6v835svj8u3gsez@10.71.1.138

From: "2495"<sip:2495@172.16.239.202>;tag=j6gezzx8

To: <sip:0628822118@172.16.239.202;user=phone>;tag=vwmm54fx

CSeq: 4 REFER

Allow: INVITE,ACK,OPTIONS,BYE,CANCEL,REGISTER,INFO,PRACK,SUBSCRIBE,NOTIFY,UPDATE,REFER,MESSAGE,PUBLISH

Contact: <sip:0628822118@172.16.239.202:5060;user=phone>

Content-Length: 0

 

However the INVITE message sent from 172.16.239.202--->10.71.16.155 contains in the SDP body just the RTP payload (G722 codec)

 

INVITE sip:2207@10.71.16.155:5060;transport=udp SIP/2.0

Via: SIP/2.0/UDP 172.16.239.202:5060;branch=z9hG4bKm44vnsarmdyhswafya5glwgay

Call-ID: nvrhlwsvdyy55al4nrgwwrx5arvrfyn5@172.16.239.202

From: "2495"<sip:2495@172.16.239.202;user=phone>;tag=rh4f5dgl

To: <sip:2207@10.71.16.155>;tag=1415790462

CSeq: 4 INVITE

Contact: <sip:2495@172.16.239.202:5060;user=phone>

Max-Forwards: 70

Content-Length: 233

Content-Type: application/sdp

 

v=0

o=HuaweieSpaceV200R003C20SPCb00 162326 162328 IN IP4 172.16.239.202

s=Sip Call

c=IN IP4 172.16.239.202

t=0 0

m=audio 10928 RTP/AVP 101

a=rtpmap:9 G722/8000

a=ptime:20

a=rtpmap:101 telephone-event/8000

a=fmtp:101 0-15

 

The Astra IP Phone replies with a 488 Not Acceptable Here since it can only support just the below codecs accepted in the earlier INVITE/200 OK sequence

 

a=rtpmap:8 PCMA/8000

a=rtpmap:0 PCMU/8000

a=rtpmap:18 G729/8000

 

 

IsCallMsg:[Y], Direction:[10.71.16.155--->172.16.239.202]

SIP/2.0 488 Not Acceptable Here

Via: SIP/2.0/UDP 172.16.239.202:5060;branch=z9hG4bKm44vnsarmdyhswafya5glwgay

From: "2495"<sip:2495@172.16.239.202;user=phone>;tag=rh4f5dgl

To: <sip:2207@10.71.16.155>;tag=1415790462

Call-ID: nvrhlwsvdyy55al4nrgwwrx5arvrfyn5@172.16.239.202

CSeq: 4 INVITE

Allow: INVITE, ACK, CANCEL, BYE, NOTIFY, REFER, OPTIONS, UPDATE, PRACK, SUBSCRIBE, INFO

Allow-Events: aastra-xml, talk, hold, conference, LocalModeStatus

Server: Aastra 6731i/3.3.1.2234

Supported: path

Content-Length: 0



Root Cause

The root cause of this issue was that the Astra IP Phone could not support G722 codec; the only codec advertised in the RE-INVITE sent and the call failed with a client failure SIP error 488 Not Acceptable Here.

After customer enabled for testing purposes only on one phone G722 the transfer worked fine however he requested to disable the G722 in the unified gateway to avoid future interoperability with Astra Phones.


Solution

To define the codec supported in the unified gateway by using the following commands in enable mode:

1. First you need to check the output of the command "show system information" to see the Voice Code and Decode Type:




Afterwards input the below command in order to modify the codec list:

config system codetype G711A&G711U&G729&G723&AMR_WB&iLBC_1520&iLBC_1333

And afterwards check again the output of command “show system information” to make sure that G722/G7221_24/G7221_32 are not present and test again.


END