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SPA8000 Calls from IPHONE 8 or above ring but cut off on answer

charles
Level 1
Level 1

Have SPA8000  connected to a Telco SIP gateway.     Have a problem that Incoming Calls from IPHONES (started 4 weeks ago)  ring but hang up on answer.  other calls are OK  from landlines and android.

 

(IP address have been replaced with names)

 

Trace from a IPHONE Call

 

call from IPHONE to SPA8000 (Fri 2021-11-12 05:56:44 UTC)

RingPartySipIP --> TelcoSIPSrv01 --> CalledPartySipIP, INVITE (SDP)
RingPartySipIP <-- TelcoSIPSrv01 <-- CalledPartySipIP, SIP: 100 Trying
RingPartySipIP <-- TelcoSIPSrv01 <-- CalledPartySipIP, SIP: 180 Ringing
.
TelcoSIPSrv01 <-- CalledPartySipIP, SIP: 200 OK (for INVITE) (SDP)
m=audio 16430 RTP/AVP 8 100 100
a=rtpmap:8 PCMA/8000
a=rtpmap:100 NSE/8000
a=fmtp:100 192-193
a=rtpmap:100 telephone-event/8000
a=fmtp:100 0-15
a=ptime:30
a=sendrecv
.
.
RingPartySipIP <-- TelcoSIPSrv01, SIP: 500 Server Internal Error
.
.
2021-11-12 05:56:46.944ISC TelcoSIPSrv01 The received SDP contained two rtpmap or fmtp lines for the same codec
.
Two rtpmap or fmtp lines have been found for the same codec.
The SDP failed to parse. This may cause call failure.
Payload ID: 100
Duplicated attribute: rtpmap
SDP:
m=audio 16430 RTP/AVP 8 100 100
a=rtpmap:8 PCMA/8000
a=rtpmap:100 NSE/8000
a=fmtp:100 192-193
a=rtpmap:100 telephone-event/8000
a=fmtp:100 0-15
a=ptime:30
a=sendrecv

 

Telco says this call failed because of Duplicated attribute: rtpmap

Customer's (SIP: 200 OK (for INVITE) (SDP)) has rtpmap:100 for two different things

a=rtpmap:100 NSE/8000
a=fmtp:100 192-193

This rtpmap:100 NSE/8000 is used for switching from voice to passthrough for fax/modem communication without involving SIP

and a=rtpmap:100 telephone-event/8000 <<<<< this is incorrect, for a telephone-event/8000 it should be a rtpmap:101, not 100

 


Now below is a good call sample:


View call from ANDROID to SPA8000 (Wed 2021-11-24 01:50:38 UTC)


RingPartySipIP --> TelcoSIPSrv01 --> CalledPartySipIP, INVITE (SDP)
RingPartySipIP <-- TelcoSIPSrv01 <-- CalledPartySipIP, SIP: 100 Trying
RingPartySipIP <-- TelcoSIPSrv01 <-- CalledPartySipIP, SIP: 180 Ringing
.
TelcoSIPSrv01 <-- CalledPartySipIP, SIP: 200 OK (for INVITE) (SDP)
m=audio 16410 RTP/AVP 8 100 101 <<<<<<<<<<<<
a=rtpmap:8 PCMA/8000
a=rtpmap:100 NSE/8000
a=fmtp:100 192-193
a=rtpmap:101 telephone-event/8000 <<<<<<<<<<<<
a=fmtp:101 0-15
a=ptime:30
a=sendrecv
.
.
RingPartySipIP <-- TelcoSIPSrv01, SIP: 200 OK (for INVITE) (SDP)
m=audio 51938 RTP/AVP 8 101
a=sendrecv
a=rtpmap:8 PCMA/8000
a=rtpmap:101 telephone-event/8000 <<<<<<
a=fmtp:101 0-15
a=ptime:30

 



 

Does any one know what setting I need to change in the SPA800  to change   100  to 101  as the Telco is suggesting ???

3 Replies 3

Hi, please check the Admin -> Advanced menu
and so Voip -SIP menu

sip_menu.jpg
 

In this menu change the AVT Dynamic Payload to 101. You can find this option in the SDP Payload types menu:

sdp.jpg

 

Regards.

Thanks for the reply,

My AVT Dynamic Payload is already 101   should I change the NSE Dynamic Payload to 101 ????

 

sip.png

Hi, NSE is a Cisco proprietary protocol used to manage fax and modem transmissions.
You cannot disable it but try to change the NSE value from 100 to another value in the available dynamic payload range: 96-127 dynamic

You cannot use an already config value like 96, 97, 98, etc.
Set for instance 106.

 

Let me know the result.
Regards.