3GPP Technical Specifications

For an IP Multimedia Subsystem (IMS) environment, Polycom has introduced support for a subset of the 3rd Generation Partnership Project technical specifications (3GPP TS) 24.229 , 24.615 , and 24.629 .

In addition, Polycom phones provide partial or complete support for the following RFCs:
  • RFC 3327
  • RFC 3608
  • RFC 3680
  • RFC 6665
  • RFC 6228
  • RFC 3261
  • RFC 5009
  • RFC 7462
  • RFC 7329
  • RFC 6026
  • RFC 3581
  • RFC 6947
VVX phones support the following IMS feature enhancements:
  • The call waiting ring-back tone plays to inform users that a call is waiting at the far end.
  • The SIP Response Code 199 (defined in RFC 6228) is supported.
  • The Path extension header field in the SIP Register request message allows accumulating and transmitting the list of proxies between a user agent and Registrar server.
  • The caller phone can support the p-early-media SIP header that determines whether the caller phone should play a network-provided media or its own media as a ring back tone.
  • The VQMon messages generated by the phone can contain service route information in SIP route headers.
  • In a NAT network, a phone may need to send keep-alive messages to maintain the IP addresses mapping in the NAT table.