Comparing alternatives for enterprise VoIP and VoIP access.

Pitfalls on the Low End

Low-end gateways can be very attractive to today's VoIP buyer. Most IT organizations are working with very tight budgets. And many do not have highly ambitious plans for their initial VoIP deployments. They simply want to piggyback voice calls on their data network's existing IP connections. So it's easy for them to be seduced into purchasing a simple, no-frills VoIP gateway to ostensibly limit costs and complexity.

This is rarely a wise decision. Low-end gateways are rarely adequate for today's enterprise VoIPrequirements. Even in cases where they may be able to meet an immediate, short-term need, they will not be able to support evolving technical and business requirements in the future.

Specific common shortcomings in low-end gateways include:

Poor interoperability with the PBX
Low-end gateways simply convert analog signals from a phone line to a stream of packets that can travel over an IP link. They are therefore unable to interoperate with or leverage the power of the corporate PBX. This can make installation in the existing enterprise communications environment problematic. Users may be required change their dialing habits - something most are disinclined to do. So any cost savings can quickly be consumed by installation and configuration work.

Lack of enterprise-class capabilities
Low-end gateways are limited-use devices with little or no call routing capability. They are mainly intended for "second line" applications that supplement a separate regular phone line. Thus, they typically route all calls to a central point where the intelligence resides. As a result, they cannot support basic Vo I P functions such as network "hop off" or "hop on" that allow, for example, the transatlantic portion of a call from an office in the U.S. to a customer in France to be carried over a corporate WAN connection to an office in Paris before being passed to a local phone company - thereby eliminating international phone charges. Reliance on a central point-of-intelligence also leaves these gateways completely vulnerable to a failure of that central point.

NAT headaches
Many organizations use network address translation (NAT) on their routers and/or firewalls as a security measure and as a way of increasing the number of IP addresses available for their internal use. But, because NAT masks internal addresses from the outside world, it can also make it difficult or impossible to set up point-to-point VoIP sessions with external users. Low-end gateways that lack an effective mechanism for automatically and securely traversing these NAT boundaries can therefore cause significant implementation headaches.

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