The Frame Relay Forum has finally ratified a standard for voice traffic over frame relay networks. The FRF.11 implementation agreement is a set of standards for vendors that want to build networking system in which compressed voice traffic can piggy- back on access lines that are carrying data, to take advantage of any spare bandwidth there might be. The hope, obviously is for interoperability between different vendors’ products, and eventually, between voice over ATM and voice over IP networks standards as well. Products – Voice Frame Relay Access Devices (VRADs) – are expected to roll out straight away, though forum members at the announcement at Networld+Interop this week was reluctant to name names of products in the pipeline, for fear of appearing to be getting one over on their Forum colleagues. The default compression algorithms chosen are G.727 EADPCM 32Kbps, offering about 2:1 compression rates and suited to embedded applications, and G.729/G.729A CS-ACELP 8Kbps algorithm, that offers a higher ration, about 8:1. Vendors can support either or both to be compliant. Virtual Connections (VCs) are also defined in the spec, which enables up to 255 voice and data sub-channels to be carried over a single VC through a frame relay network. The spec makes it possible for any kind of VRAD at one end of the network – it could be a PBX, fax, or multiplexor for example, to exchange voice and signaling with any type of VRAD on the other end. This makes for less compression and decompression – only once in each VRAD – that means better voice quality, as does the need to have only one connection per location. There is no support yet for signaling or for negotiation – the ability to decide which compression algorithm to use. Support for both had been due by now, as getting this implementation ratified took a lot longer than thought – Forum officials said there were about 70-80 vociferous attendees at each meeting – they wouldn’t put a time frame on when the spec will be revved.
