Application Note - Call Routing Engine

This virtualisation enables the support of many dial plans, routing tables as well as digit manipulation (DM) profiles.  The CRE’s flexibility is shown in the dial plan and routing tables below.

Interoperability and Peering

The biggest challenge for today’s VoIP operators is interoperability with other connecting networks and elements.  With the growth of SIP and the large number of SIP devices on the market, developers have implemented SIP in many different ways. Some vendors use certain methods and format their messages in specific ways, all for valid reasons, however, the nuances of these different implementations means that one device cannot talk directly to another device successfully as they do not understand each others SIP “dialect”.  The approach to this problem so far has been for the SBC vendor to write a patch for the SBC which normalizes the message.  This approach tends to be slow and cumbersome and when time is of the essence, as it usually is with a commercial peering agreement, any operational issues can result in a loss of revenue.    Newport Networks’ approach to this problem is to provide a user-friendly tool that operators can use to pre-programme the profile of the interconnecting network, including message formatting, network behaviour and emulation. This means no need for any system downtime to implement a new patch, which enables Newport’s approach to be downtime free and simple to implement. The interoperability tool also includes support for 3GPP SIP.

The next challenge is in securing the peering interconnect or SIP trunk.  Newport’s SBC enables Access Control Lists to be created, VLANs for private peering and overlapping IP address support (rfc1918).  When combined with Newport’s CRE application peering security can extend to trunk group prefixing, validation and authorization.

No matter whether the service provider offers wholesale VoIP, arbitrage or SIP trunking services, the network should be able to deliver these services from a single platform, which means that the same set of tools should be available for all service types such as Interop profiles, dial plan management, digit manipulation as well as routing and service reporting.

Newport Networks’ CRE application extends to offering a virtual partitioning feature, which enables different operators, such as ITSPs, to operate their own private virtual exchange with their own call routing preferences, digit manipulation rules and traffic reports and metrics.  Access to the virtual partition is via SSL over the internet or a private VPN.

Call Routing

Wholesale peering and arbitrage differ in the way the LCR or routing is managed. Wholesale peering prices do not change as frequently as arbitrage prices and SIP trunking prices for the Enterprise market rarely change.  Flexibility in how the optimized route is achieved is the key to being agile and fast to market with any commercial changes.  Newport Networks’ CRE application includes an LCR tool which enables the operator to upload new rate sheets, calculate a new LCR, preview and then submit.  If any minor changes are required, Newport’s override tool allows you to customize your Least Cost Routing before being activated.  As this is an integrated tool, moves, adds and changes are simple and quick to apply. The CRE application has no limit in the number of dial plans and LCR tables, therefore the operator has the option to create various levels of call quality routing such as Gold, Silver and Bronze.

Operators that have a distributed network can centralise the CRE application and distribute the SBCs to the optimum ingress and egress points in the network.  In this case there can be multiple Call Routing Engines distributed in the network which automatically synchronise to offer geographic redundancy and high availability, not just in the data centre, but across the network.

Operators with a centralised point of presence can implement Newport Networks’ CRE to support up to 100,000 concurrent calls in a single telco rack which includes Newport’s SBC, CRE and reporting engine.  Redundancy can be provided at both the application and hardware layers as well as resilience at the network layer.

Combining the 1460 SBC platform, which offer no single point of failure, or the 310 which offers unparalleled levels of SBC application redundancy, with the Newport Networks CRE application means a solution can be created to provide the levels of redundancy required by an operator.

Conclusion

Newport’s advances in SBC features such as a programmable interoperability tool for network and device emulation, and network integration capabilities such as Link Aggregation Groups, means that Newport can offer a complete, fully programmable peering solution that delivers call routing and SIP trunking services.

Interconnecting NGN and IMS networks is enabled with full 3GPP signalling support and Newport’s interoperability tool. Add granular session control, customisable Codec support, advanced Media Edge Routing and a powerful Least Cost Routing tool and this is a network solution that will provide you with a fast time to market, application scalability and a migration path to IMS. ■

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