Will multilink frame relay catch on?

The Frame Relay Forum is working on an Implementation Agreement for multilink frame relay, which we said in an earlier newsletter is a key technology trend that bears watching. But the question remains -- exactly how important will multilink be?

Multilink services allow the use of multiple transmission facilities - multiple 56/64K bit/sec links or multiple T1 links - to be aggregated and treated as a single logical frame relay stream. The need for multilink stems from the simple fact that dedicated access services still make quantum leaps from 56/64K bit/sec to T1/E1 to T3/E3 and above, with rarely any granularity in between. Consequently, the popularity of interfaces at certain speeds tends to clump around those upper limits that don't require these leaps (and associated service cost increases) for more bandwidth.

There does seem to be some pent-up demand for multilink services. Our poll this winter at Webtorials.com indicated that most of the respondents would move to an incrementally higher speed if the services were available (see www.webtorials.com/public/survey1/survey1.htm). Multilink frame relay provides a simple path for doing this. The idea is simple: send frames for a single logical frame relay user-network interface (UNI) across the access facilities using parallel transmission paths on a frame-by-frame basis. While this involves upgrading software -- and possibly upgrading the hardware at both ends of the access circuit -- it avoids the most costly component - upgrading the actual physical transmission facilities. Consequently, multiple 56/64K bit/sec circuits can be used to provide fractional T1 access without provisioning a T1, and multiple T1/E1 circuits can be used to provide fractional T3/E3.

This provides an especially attractive opportunity for moving the majority of users to higher speeds. About two-thirds of frame relay users are still using 56/64K bit/sec access links, which provides an attractive means for upgrading to a higher speed with nearly linear price increases by the DS0 (64K bit/sec increment), thus eliminating the need for quantum leaps to T1/E1 access facilities.

Coming: High-speed multilink, potential pitfalls and implications for voice over frame relay.

Would YOU use multilink frame relay? Fill out our new survey at www.webtorials.com/survey2.htm and we'll enter you in a drawing for a cool Webtorials.com shirt.

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Steven Taylor, consultant and broadband packet evangelist, and Joanie Wexler, an independent networking technology editor and writer, team up to bring you this analysis and commentary. Taylor specializes in education and market analysis, and Wexler adds incisive reporting and research. For more detailed information on most of the topics discussed in this newsletter, connect to www.webtorials.com, the first Web site dedicated exclusively to market studies and technology tutorials in the Broadband Packet areas of Frame Relay, ATM, and IP. Feedback and additional topic ideas are welcome. Please contact taylor@webtorials.com or joanie_wexler@mindspring.com.

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