Delivering Value-Added Services between IP Networks
Service providers are now building value-added services with all IP-based elements, typically using the SIP protocol. These emerging SIP-based networks offer enormous potential for generating new services and increasing revenue per subscriber, but the introduction of IP throughout the network also creates challenges. For all-IP environments, new elements are required that can mediate signaling, transcode among different media formats, and handle basic security issues. The Dialogic® IMG 1010 Integrated Media Gateway is exceptionally well-suited for these tasks.
Note: Although the IMG 1010 will be discussed here, Dialogic offers integrated gateways that provide both higher and lower densities.
Multimedia Border Requirements between Network Elements
An IMG 1010 is useful where there is a need to translate between the SIP variations used by different vendors in order to deliver enhanced services. The illustration “Multimedia Border Requirements between Network Elements” shows how an IMG 1010 can be used between network elements. In this example, a SIP-based softswitch supporting SIP over UDP needs to communicate with a hosted voice platform that uses SIP over TCP. The IMG 1010 provides SIP mediation between the two platforms and media transcoding between the platforms for tones or voice. In this situation, the IMG 1010 plays a role much like a PSTN-to-IP media gateway, but the connections on both sides are IP-based. The IMG 1010 provides value by reconciling the signaling and the media between the softswitch and the voice platform, and by performing these functions using a single, small form factor device.
Multimedia Border Requirements between Network Elements
Multimedia Border Requirements on the Network Edge
Another role for an IMG 1010 is to provide an intelligent link at the network edge between two different IP networks. Carriers have often used SBCs in this role, but in cases where there are requirements for media transcoding between the networks, an IMG 1010 can offer a more comprehensive approach.
The illustration “Multimedia Border Requirements on the Network Edge Example” shows how an IMG 1010 can be used on the network edge. In this example:
- A carrier must handle telephony traffic that is sent from a softswitch to the network edge, and then sent across a network boundary. The traffic needs to cross the network boundary in order to connect to a feature server controlled by a service provider who offers hosted services on the Internet.
- The carrier needs to use SIP to connect to the feature server, but also wants extra protection for the signaling, so it issues a request for SIP over TLS to the feature server.
- The service provider wants to conserve bandwidth, so it requests that the media be converted from uncompressed G.711 voice into compressed G.729.
- The carrier wants to mask its IP topology when communicating with the service provider, so it uses the back-to-back user agent of the IMG 1010 to shield the internal IP addresses of the carrier from the service provider.
Multimedia Border Requirements on the Network Edge
An IMG 1010 provides value to the carrier by securing the signaling for passage across the internet, transcoding the voice media per the requirements of the service provider, and masking the carrier’s IP topology.