VoIP Industry Newsletter: On Perfecting Call Routing

I started my career as a Provisioning Engineer building a T1/T3 network for voice origination and termination. Then, like now, the whole idea was to build a network that allowed you to ‘perfect’ routing of telephone calls. ‘Perfect’ as you may have noted, I write in quotes for a reason. Perfect routing has a different meaning for every carrier and service provider. The meaning depends on many business factors that change over time or that are based on shifting product type, customer expectations, use of network, pricing, etc. When I was provisioning T1s and T3s back in the ‘90s, I reluctantly understood that ‘perfect’ wasn’t the goal and that ‘better’ would suffice.

Now, though, with a decade of VoIP and SIP, we’ve seen many technology changes that could bring this goal into sight. Among these changes are rapidly growing wireline and wireless broadband networks, extensive carrier and service provider VoIP peering, over 300 million global VoIP end-users, Electronic Number (ENUM) databases and still few regulatory boundaries (though they persist or in many cases remain to be drawn). Perhaps it might be the time to ‘perfect' routing. With readily available technology tools and diligent management of the data inputs and required operational metrics, carriers and service providers, on balance, are moving closer to ‘perfect’ routing. As a person that appreciates an orderly universe, I am excited to see more route/ cost professionals devoting time and effort to this cause.

The following are some of the common types of routing that carriers and service providers are trying to ‘perfect’ and how tools available through VoIP technology can help:

1. Carrier Intra-network Routing - Within a carrier or service providers network there are several ways to standardize procedures via technical prefix management, digit manipulation, dial-code normalization, SIP header manipulation, and generally  to move signaling and media most efficiently between internal POPs. As in many cases below SIP Redirect messaging, stateful session management via session controller technology and network data capacity management allows an operator to achieve routing to their very specific requirements.
2. Origination Routing – There are still many regulatory variables that differ by jurisdiction, dial plan, operating companies, etc., as you will read about in the Voices From the Industry article at the end of this quarter’s newsletter. That being said, soft switches and/or session border controller technology can manage digits, dynamically match codec, match protocol and forward to any network device or end point on the Internet.
3. Termination Routing – Telephone call transportation and termination can be ‘perfected’ using VoIP at least to the point that data inputs are correct and meticulously managed. Because the cost of a public Internet interconnect is nominal, interconnects are abounding. I.e., instead of two options to route telephone calls to Mexico and 500 breakouts, you can have 20 options and 20,000 breakouts. And there are also exchanges and minutes clearinghouses where a single interconnect nets you dozens of routing options to every destination. Smart management of costs, pricing and the ability to manage the quality of service are all possible across heterogeneous network types, providing that they all use packet routing variants. This has a huge potential for an operators ability to save money and control quality but also to minimize hops in the larger Public Packet Telephone Network (PPTN) (see #5 below on Media Management).
4. ENUM and Data ‘dips’ – There is a growing list of places to make real-time ‘dip’ for information. Neustar’s Number Portability database and Telcordia’s various ENUM databases, among others, are necessary and popular as are services from Xconnect that are aggregating information to more intelligently route calls. With VoIP technology you can incorporate one or more of these databases into your routing matrices. As VoIP device addressing becomes more complicated — i.e., in addition to telephone numbers (DIDs) we are starting to find SIP User IDs as valid addresses for call routing — this type of real-time look-up service is important for ‘perfecting’ certain types of routing. These and other data sources should be accessed by more carriers for cost savings alone.
5. Call Stream/Media Management – Using VoIP protocols like SIP, SIP-B, MGCP, SCCP from the desktop on a call gives an operator (or a pair of operators depending on who is being called) extensive control over the media stream. Some of the highest user-rated features of VoIP like simultaneousring, find me, voicemail to email, etc., all use split and redirected call streams which easily make use of ‘cloud’ systems - leveraging the ubiquity of the Internet. While this type of ‘perfecting’ of routing is less likely to save money or improve quality, it expands the capabilities of the technology.

If you couple together these five advantages of using VoIP technology and Internet network topology together with diligent attention to managing the data integration used to make routing decisions, you can make significant strides towards perfecting your routing.

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