I would like share some experience on the reported issue. As you mentioned that Volte users sending 183 SDP. So I suppose it is not related to ring back tone for CPE user since it is only intimation of session progress for CPE or playing tone from Volte user if there is any early media.
In Other case, Volte user may need to send 183 SDP if there is any pre- Alerting SRVCC implentation is required in the network. In this case ring back tone to CPE also not required. Local ring back tone to CPE only seems to be related to 180. If the Volte user send 180 SDP in that case it may be issue for the CPE unable to provide ring back tone to CPE user since most of the CPE configured ring back tone only 180 w/o SDP. Again Volte user may need to send 180 SDP if there is requirement for Alerting SRVCC implementation in the Network. If Alerting SRVCC is required, Volte user need to send 180 SDP for bearer setup during ringing to initiate HO. In that case CPE must be modified to accept 180with SDP to provide local ring back tone instead of currently configured local Ring back tone 180 w/o SDP. Otherwise as a whole, without Alerting / pre-alerting SRVCC , Volte user can send 180 Without SDP to tell CPE to play ring back tone locally. Thanks Sent from my BlackBerry 10 smartphone. Original Message From: Dale R. Worley Sent: Friday, 23 September 2016 22:38 To: Tarun Gupta Cc: sip-implementors@lists.cs.columbia.edu Subject: Re: [Sip-implementors] No RBT Fixed IMS CPE's Tarun Gupta <tarun.gu...@ericsson.com> writes: > It has been observed whilst testing our WiFi/VoLTE solution that when > a Fixed IMS service (such as Broadband voice or SIP Trunking) CPE > calls one of our WiFi/VoLTE subs, they do not hear any ring back tone > as call setup progresses. It transpires that this is because our VoLTE > UE's always reliably send an SDP in the 183 Session Progress which > means that the Fixed IMS service CPE's sit there waiting for the > remote endpoint to provide early media ring back tone which of course > will never come from the VoLTE UE's. > > Has anyone experienced this in their deployments and if yes, what > solutions were put in place to fix this? (for example network provided > RBT? removing preconditions?) I would suggest adjusting the VoLTE UE's to not send SDP (establish a session) until they are prepared to send media, either ring-back tone or user media. Otherwise the CPE has to test the provided media to see if it is silent. Dale _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/sip-implementors ________________________________ The content of this email together with any attachments, statements and opinions expressed herein contains information that is private and confidential are intended for the named addressee(s) only. If you are not the addressee of this email you may not copy, forward, disclose or otherwise use it or any part of it in any form whatsoever. If you have received this message in error please notify postmas...@etisalat.ae by email immediately and delete the message without making any copies. _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
