SIP-SS7 Gateway CNAM Interworking for Legacy Network Compatibility
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Solution Overview
Problem
Existing communication systems face compatibility issues in providing Calling Name (CNAM) services for SIP originated calls terminating in circuit-switched networks, as SIP uses subscriber addresses that are not recognizable by legacy equipment, leading to incompatibility with conventional CNAM query mechanisms.
Innovation Solution
A method involving a SIP-SS7 gateway that assigns a temporary telephone number to SIP calling subscriber identifier information, generates an SS7 call setup message, and communicates this information to a CNAM interworking function module, which stores and retrieves the necessary information to facilitate CNAM queries and responses, enabling compatibility with legacy systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If SIP subscriber addresses are used for calling identification, then SIP calling functionality is enabled, but compatibility with legacy CNAM query mechanisms is lost
Solution Approach 1:
The patent introduces a CNAM interworking function (CIF) module as an intermediary between the SIP network and the legacy SS7 network. This module receives CNAM queries from terminating switching offices, translates them into SIP lookup requests, and returns the appropriate calling name information. The CIF acts as a mediator that bridges the incompatible addressing schemes of SIP (URI-based) and legacy networks (telephone number-based), enabling CNAM services to function seamlessly across both networks without requiring changes to either the SIP subscriber addresses or the legacy CNAM query mechanisms.
2Reliability
If temporary telephone numbers are assigned to SIP subscribers, then CNAM queries can be translated, but additional network components and complexity are introduced
Solution Approach 1:
The CNAM interworking function (CIF) module is designed to perform multiple functions within a single component. It not only translates CNAM queries from SS7 format to SIP format, but also maintains a mapping database between temporary telephone numbers and SIP subscriber addresses, manages the assignment and release of temporary numbers, and handles both incoming CNAM queries and outgoing SIP call setup. This multi-functional design consolidates what could be separate complex systems into a single integrated module, reducing overall network complexity while maintaining full CNAM service compatibility.
Data Source
AI summary
Methods, systems, and computer program products for communicating CNAM services for SIP originated calls terminating in a circuit switched network is described. In one embodiment, the method includes, at a SIP-SS7 gateway, receiving a SIP call setup message that includes a SIP calling subscriber identifier information, associating a temporary telephone number with the SIP calling subscriber identifier information, generating an SS7 call setup message associated with the SIP call setup message, wherein the SS7 call setup message includes the temporary telephone number, and communicating the temporary telephone number and SIP calling subscriber identifier information to a calling name interworking function (CIF) module. The method also includes, at the CIF module, storing the temporary telephone number and the associated SIP calling subscriber identifier information in a local cache, receiving a CNAM query message containing the temporary telephone number from a terminating switching office, and transmitting a CNAM response message to the terminating switching office including the SIP calling subscriber identifier information.