SIP SIP-I Interworking
The Oracle Communications Session Border Controller (SBC) supports the Interworking function (IWF) between SIP and SIP-I networks by including ISUP message information in the body of SIP messages, and formatting SIP message information for SIP-I, from which subsequent devices use for ISUP. The SBC has broad support for ITU Specification Q.1912.5, which defines SIP-I. This specification defines ISUP message encapsulation and the mapping between SIP headers and ISUP parameters. This ITU specification is considered a superset of the IETF's SIP-T specification. The SBC also complies with IETF specifications on the use of MIME within SIP messages.
Within the context of SIP SIP-I IWF, the Oracle Communications Session Border Controller (SBC) operates between the SIP network and a Media Gateway Controller Function (MGCF) generating and interpreting SIPI as an interim step for originating and/or terminating services between SIP and ISUP. The configurable categories of interworking information include:
- Signaling Message and Parameter IWF
- Diversion Information IWF
- ISUP Version IWF
You configure sip-profiles and sip-isup-profiles and apply them to session-agent, sip-interface or realm to enable interworking. These configurations determine the base actions taken on the target traffic. The SBC supports three methods refining the interworking. You can them use the following configuration methods to refine the interworking by specifying information, such as header parameter detail, for ingress and/or egress traffic:
- Interworking with Header Manipulation Rules (HMR)
- Interworking with Session Translation
- Native SIP SIP-I Interworking Support
You configure the SBC to use one or a combination of these methods. Note the processing order in which the SBC executes these functions, explained in this document, as each subsequent function operates on the results of the prior function.
By default, you configure HMR for all SIP to SIP-I interworking, with the exception of IAM interworking. This is a legacy means of configuring this interworking, and is widely deployed.
Session translation configuration is similar to HMR, but is for less complex message manipulation. You configure session translation elements to perform specific text changes on a limited number of SIP and/or SIP-I objects using offsets to find your target objects, and add, change or delete the text you specify. You can also use session translation for called and calling number manipulation for SIP to SIP signaling.
Native SIP SIP-I interworking features automatically perform interworking on messages in addition the IAM. For native SIP SIP-I interworking, you simply enable it and the SBC performs the changes described herein. Advantages of Native IWF configuration include:
- Avoids the complexity of HMR configuration, reducing implementation time and resources
- Provides session statefulness within the SBC for these interworked sessions
- Overcomes the HMR limitation of HEX to decimal arithmetic, simplifying reason code mapping
- Allows better system performance
Regardless of the method you choose, at a high level, for SIPI to SIP interworking, the SBC constructs the SIP headers based on the SIPI information, then removes the entire SIPI MIME block. For the SIP to SIPI direction, the SBC interworks IAM parameters as described in this document and inserts the block.
Note:
The SBC does not comply with every aspect of ITU Specifications Q.1912.5, which defines SIP-I.