Field guide to frame relay

Communications News, May, 1998 by Ron Kovac

Pricing and features vary widely among frame relay service providers, so you must determine what's right for your needs.

These times of rapidly changing technology and policy--and of tight budget dollars--demand a review of telecommunication connection costs. Cost-conscious businesses need to perform a thorough assessment of their telecommunications needs followed by a review of available technologies that will meet these needs. Frame relay is a technology that should be considered, for it is typically lower in price and offers advantages over other connection strategies.

To help telecommunications mangers make decisions regarding frame relay services, we researched the industry and interviewed 18 frame relay service providers. This information should help you decide if frame relay is right for you and assist you in selecting an appropriate service provider.

BRIEF OVERVIEW

Frame relay is a form of packet-switching technology that depends on newer and higher-quality transmission lines. It typically offers lower costs and higher performance than other technologies and is perfect for bursty data over WANs.

Unlike its predecessor, X.25, frame relay does not provide error correction. It relies upon higher-level protocols (i.e., TCP/IP) to correct errors, allowing faster network speed with less overhead and responsibility for service providers. This translates to lower costs to the user. Similar to X.25, frame relay supports multiple virtual circuits via a common network interface.

The most commonly implemented frame relay connections are PVCs (permanent virtual circuits). As a PVC is implemented, a permanent circuit is established between two locations. A single PVC allows one site to communicate with a defined second site. By combining PVCs, a fully meshed network can be provided within a frame relay network.

A less common type of frame relay implementation is the SVC (switched virtual circuit). A SVC provides on-demand connections between two locations within frame relay and is typically use sensitive. When a SVC is used, the subscriber can connect to any other subscriber site with SVC capabilities.

Another unique characteristic of frame relay is its CIR (committed information rate). The CIR is the minimum throughput of data that you can expect in transmission. CIR is usually contractually guaranteed and is sometimes charged for (the higher the CIR, the more dollars paid). CIR is established for each PVC or SVC. An upside to frame relay is that service providers usually let you burst over your PVC nominal rate without additional charges.

LOOKING FOR A PERFECT FIT

In searching for frame relay service providers, we identified 18 organizations that had industry recognition. Next, we developed a survey instrument based on criteria we felt might be helpful to a frame relay shopper. These criteria include available speeds, guarantees such as provisioning, and specific features that may set the service providers apart.

For example, one of the features surveyed is the offering of T3 access for frame relay. This feature is essential if a customer has multiple sites sending large amounts of data to a host. Other features surveyed include the offering of customer premise equipment (CPE), frame over an ATM backbone, SVC availability, and customer network management (CNM) availability. CNM is necessary when the customer has the need to directly monitor the frame network and pull various performance criteria of the network for internal management.

PRICING CONFUSION

Price is typically a critical variable for the customer. Originally, we had hoped to provide a comparative pricing table, but we soon realized there were far too many variations for this display to work. Provider pricing schemes were vastly different, and we found prices were almost always negotiable. Sometimes we wondered if pricing was the most complex part of the technology. Therefore, we have provided frame relay service information that is based on the vendors' service offerings.

Frame relay pricing is made up of four basic elements: 1) the committed information rate (CIR), 2) the port charge, 3) the access lines and, 4) the customer premise equipment (CPE).

The CIR lies within the frame relay cloud and is typically priced by speed. Some providers do not charge for the CIR, which implies the cost is bundled in other ways. To reduce costs, one would choose a CIR speed lower than the speed of the access line. Service providers offer 0 Kbps CIR (or at least close to 0 Kbps) so the consumer may reduce costs and the frame network may maximize throughput. Be aware that 0 Kbps-based CIR can result in a "send and pray" mode depending on overall provider frame traffic.

All surveyed frame providers' prices for CIR are distance-insensitive, allowing cross-country communication at reasonable costs.

The port charge allows access to the frame relay cloud. Port pricing is based on speed, with the higher speeds demanding the highest cost. The port speeds you select will typically match your access line speed.