12-18-2021 08:31 PM - edited 01-23-2022 01:45 AM
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 ???
01-21-2022 02:18 AM - edited 01-21-2022 02:19 AM
Hi, please check the Admin -> Advanced menu
and so Voip -SIP menu
In this menu change the AVT Dynamic Payload to 101. You can find this option in the SDP Payload types menu:
Regards.
01-23-2022 01:44 AM
Thanks for the reply,
My AVT Dynamic Payload is already 101 should I change the NSE Dynamic Payload to 101 ????
01-28-2022 12:15 AM
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.
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