SIP

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Session Initiation Protocol, more commonly known as SIP, is a signaling protocol for packet-based networks and is commonly used, along with H.323 to provide signaling for voice over IP (VoIP) communications.


Contents

TelcoBridges and SIP

Toolpack provides support for signaling using the Session Initiation Protocol, more commonly known as SIP, for voice over IP (VoIP) communications. SIP may be used in conjunction with various voice codecs for the media component of a call. TelcoBridges Tmedia media gateways and Tdev development platforms support SIP signaling concurrently with SS7, ISDN and other signaling protocols.

SIP signaling stacks are configured for IP applications and for each Tmedia or Tdev unit requiring SIP signaling.

Based upon your system requirements, you can configure a SIP stack to carry signaling traffic over multiple transport servers, which are IP endpoints comprised of: protocol type (TCP/UDP), port number, IP interface, IP address, IP name, and SAPs.

A conceptual illustration is provided below:


SIP stack conceptual illustration.jpg


While TelcoBridges media gateways can perform multiple simultaneous functions such as switching and transcoding as well as deliver value-added services such as IVR or conferencing, they can also be configured to perform a single function. In this case, it is possible to configure TelcoBridges media gateway to act as a SIP gateway.


TelcoBridges' SIP Implementation

TelcoBridges' SIP implementation works on top of a couple of layers, including SIP and TUCL. In the following figure, grey boxes represent entities that need allocation on the TelcoBridges equipment. The TUCL layer is a transport layer used by SIP on our architecture. TUCL presents some advantages over a simple TCP/IP stack. For instance, it adds tracing facilities to any virtual interface.


TB-SIP-Architecture.jpg


Supported SIP RFCs

TelcoBridges supports the following RFCs for SIP:

Specification TMedia SIP stack support Toolpack API Support Media Gateway Application Support
RFC 2327 Session Description Protocol Yes Complete Complete
RFC 2976 SIP INFO Method Yes Complete Partial (For DTMF Tones Only)
RFC 3204 MIME media types for ISUP and QSIG Objects Yes Complete No
RFC 3261 Session Initiate Protocol Yes Complete Complete
RFC 3262 Reliability of Provisional Responses in the Session Initiation Protocol (SIP) Yes Complete Complete
RFC 3263 Session Initiation Protocol (SIP): Locating SIP Servers Yes Complete Complete
RFC 3264 An Offer/Answer Model with the Session Description Protocol (SDP) Yes Complete Complete
RFC 3265 Session Initiation Protocol (SIP)-Specific Event Notification Yes No No
RFC 3311 The Session Initiation Protocol (SIP) UPDATE Method Yes Partial (Only For Session Timer Refresh) Partial (Only For Session Timer Refresh)
RFC 3323 A Privacy Mechanism for the Session Initiation Protocol (SIP) Yes Partial* Partial*
RFC 3325 Private Extensions to the Session Initiation Protocol (SIP) for Asserted Identity within Trusted Networks Yes Partial (No P-Preferred-Identity) Partial (No P-Preferred-Identity)
RFC 3326 The Reason Header Field for the Session Initiation Protocol (SIP) Yes Complete No
RFC 3398 ISUP-SIP Mapping Yes Complete Complete
RFC 3515 Refer Method Yes Complete Complete
RFC 3578 Overlap Yes Partial (Conversion of ISUP Overlap Signalling into SIP en-bloc Signalling) Partial (Conversion of ISUP Overlap Signalling into SIP en-bloc Signalling)
RFC 3581 An Extension to the Session Initiation Protocol (SIP) for Symmetric Response Routing Yes Complete Complete
RFC 3665 Session Initiation Protocol (SIP) Basic Call Flow Examples Yes Partial* Partial*
RFC 3666 Public Switched Telephone Network (PSTN) Call Flows Yes Complete Complete
RFC 3764 enumservice registration for Session Initiation Protocol (SIP) Addresses-of-Record Yes Complete Complete
RFC 3891 "Replaces" Header Yes Complete Complete
RFC 3892 Referred-By Mechanism Yes No No
RFC 4028 Session Timers in the Session Initiation Protocol (SIP) Yes Complete Complete


Related actions

Refer to the appropriate Toolpack release:


References

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