SIP provider trunk configuration information and questionnaire


When working with your SIP provider to set up and configure your external trunk in PureCloud, you need to provide them with information about PureCloud. You also need to ask specific questions about configuration options. Once you have your initial trunk configuration in place, youwant to run some tests to make sure that everything is set up properly.

In this article, we provide you with  a list of PureCloud requirements. We also provide you  a list of the RFCs currently supported in PureCloud. You can use this information to assist you with a discussion with your SIP provider.

Also in this article, we provide you with a questionnaire designed to help you discuss your needs and requirements with your SIP provider. We also provide you with a test plan designed to help you make sure that your SIP trunk is configured properly.



Discuss these requirements with your SIP provider.

  • List IP addresses the carrier will use to source SIP and RTP traffic
  • SIP OPTIONS request to each Edge device for trunk failover

Functionality requirements

  • Out-of-Band DTMF (RFC2833)
  • Fax via g.711 pass-though
  • Inbound calls with and without ANI
  • Outbound calls with ANI
  • Early Media
  • Hold Support (re-invite to 0.0.0.0)
  • Incoming call forwarding
  • Always in Audio
  • Service unavailable (503 response from carrier)

SIP/RTP traffic requirements

  • Carrier must allow SIP and RTP traffic from your Edge Appliance IP Addresses
  • Sequential trunk failover is recommended for multi-Edge deployments
  • SIP port 5060 for all inbound/outbound SIP traffic
  • Recommended to use the G.711 Codec for voice traffic inbound and outbound between you and the carrier


You can tell your SIP provider that these RFCs are supported by PureCloud.

Standard Description
RFC 791 Internet Protocol (IPv4)
RFC 2327 SDP: Session Description Protocol
RFC 2833

RTP Payload for DTMF Digits, Telephony Tones, and Telephony Signals

The customer endpoints should be able to handle in-band if RFC 2833 is not  supported (by the PBX and/or the far end).

RFC 3261

SIP: Session Initiation Protocol

The transport methods supported are UDP (RFC 768) and TCP (RFC 793).

The PBX-specific agreed transport method (i.e. UDP or TCP) shall apply in both  directions between the PBX and the service.

RFC 3263

Session Initiation Protocol (SIP): Locating SIP Servers

Note: PureCloud only partially supports this RFC as SRV and NAPTR are excluded.

RFC 3264

An Offer/Answer Model with Session Description Protocol (SDP)

RFC 3311 The Session Initiation Protocol (SIP) UPDATE Method
RFC 3515 The Session Initiation Protocol (SIP) Refer Method
RFC 3550 RTP: A Transport Protocol for Real-Time Applications
RFC 3891 "Replaces" Header.
RFC 3892 Referred-By Mechanism.
RFC 3960 Early Media and Ringing Tone Generation in the Session Initiation Protocol (SIP),
RFC 4028 Session Timers in the Session Initiation Protocol (SIP)
RFC 4244 An Extension to the Session Initiation Protocol (SIP) for Request History  Information
RFC 4566 SDP: Session Description Protocol (obsoletes RFC 2327)
RFC 4904 Representing Trunk Groups in tel/sip Uniform Resource Identifiers (URIs)
RFC 5806 Diversion Indication in SIP (network accepts does not send)
ITU G.168 Echo cancellation

Download the questionnaire, which is a fillable PDF form, before you contact your SIP provider. Then use it to discuss the SIP trunk configuration options with your SIP provider and record the answers. 

Download our SIP trunk questionnaire

You can then use the answers to configure each setting for the trunk configurations within PureCloud. For more information, see Create an external SIP trunk.

Print the test plan and use it to perform the tests and record the results. If you have problems, you can then use this information to coordinate solutions with your SIP provider.

Download our SIP trunk test plan