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What ever happened to VoFR?

Mar 31, 20042 mins

* Remember Voice over Frame Relay?

As VoIP continues to gather momentum, we’re sometimes left wondering whatever happened to some of its earlier competitors.  In this newsletter, we’re going to address Voice over Frame Relay (VoFR) and next week we’ll look at Voice over DSL (VoDSL).

VoFR predates VoIP by several years.  Back in 1997, the Frame Relay Forum (now the MPLS and Frame Relay Alliance) defined VoFR as a technology to pass low-bit-rate voice over frame relay PVCs.  Interestingly, even though frame relay inherently has much lower latency and much better predictability that IP networks, VoFR was only moderately successful in the market and today it appears to be fading into the background.

There are several reasons for this lackluster acceptance.  First and foremost, VoFR’s primary strength is transporting point-to-point voice as a replacement technology for traditional “tie lines.”  As such, voice can be transported very inexpensively, and the VoFR justification is a tariff arbitrage.  However, as the price for voice has continued to plummet, VoFR – as well as VoIP – continues to be a tough sell if tariff arbitrage is the only factor.

In contrast with VoFR, VoIP really began to excel as IP PBXes started to roll out. While VoFR using switched virtual circuits (SVC) could theoretically compete with VoIP, there are still few if any widespread frame-relay SVC services available.  Additionally, VoIP, as we’ve often discussed, is becoming integrated into the entire IT infrastructure.  By contrast, frame relay is appropriately limited to the WAN transport arena.

Of course, depending on how you define VoFR, there are massive installations in place today.  Frame relay is a major carrier for all types of IP traffic, including VoIP.  However, the VoFR of today is VoIP over frame relay (VoIPoFR).


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