October 1997

Today's Networking Revolution

Frame Relay Battles Emerging Technologies and Turns Up a Winner

BY NICK BROOKS

Frame relay is by no means a new technology — it has been in the public domain since the 1980s. However, the use of frame relay has accelerated in recent years due to the highquality digital infrastructures available in many countries and the migration from self-managed leased line solutions to frame relay services, which are fully managed by a service provider.

At the same time, the growing number of service providers for frame relay services has allowed customers to benefit from high functionality and competitively priced services. With the real costs of bandwidth (in global terms) now in decline due to this increased competition, alternative networking solutions, and the Internet, frame relay is an ideal solution for many companies that need to transmit data and other traffic types to geographically dispersed sites at a relatively low cost. The technology used in both the widearea network (WAN) by the service providers and by customers in the localarea network (LAN) is also declining in price but rapidly increasing in capability and functionality. When equipment such as routers, frame relay access devices (FRADs), and hubs are supplied by the service provider, customers are able to benefit from “future proofing,” as new software upgrades to technology are introduced by the manufacturers. Costeffective alternatives to leased lines are seen as the primary driver for customers buying frame relay networks. And when these networks are fully managed by the service provider, there is generally less investment required.

FRAME RELAY DEVELOPMENTS
Many companies have, during the last 25 years, migrated their networking onto X.25 as an alternative to leased lines. This migration has given customers a fully managed, widely available service that also conforms to internationally agreed upon standards.

Tariffing for X.25 can be based either on time or data volume, and is often presented as a combination of the two. In this case, heavy use of X.25 nulls any appreciable cost benefits. Furthermore, most X.25 service providers only offer service up to 56 or 64 kbps, which, for companies in need of greater capacity, can be a limiting factor.

Although frame relay, which relies on a digital infrastructure, is not as widely available as X.25 (due to X.25’s availability on analog lines), it does support access speeds at up to 2 Mbps. The market is now seeing service providers announce plans of supporting access speeds of up to 45 Mbps and there is talk about introducing support for frame relay access at this speed sometime in the coming months.

The major problem with access at these speeds, and in fact at speeds beyond 256 kbps, is the question of availability — provided from the local carriers — of access circuits. In addition to acquiring bandwidth at these greater speeds, another major concern is the affordability of such services. While the cost of low-speed bandwidth has been in decline in the global market, the tariffs for high-speed bandwidth have not been moving in the same direction, because many bandwidth providers are uncertain about the demand and the amount they should be charging customers and service providers.

So, not only will frame relay support greater speeds than X.25, but since most networks are based on the Permanent Virtual Circuit (PVC) concept, the tariffing tends to be flat-topped. This means that customers will be charged an exact amount independent of usage, allowing budgets to be set and managed accordingly. This is very attractive to financial controllers in many companies. The flat fee would likely encompass a port on the service provider’s network, and a PVC, which will vary according to the Committed Information Rate (CIR) and the destination.

In other words, a PVC which has a CIR of 16 kbps from Los Angeles to San Francisco will be cheaper than a 16-kbps PVC linking Los Angeles to Tokyo, simply because the bandwidth required to support the channel is domestic rather than international. A PVC, in terms of frame relay, is defined by linking two halfduplex channels together, resulting in Data Link Connections (DLCs). Each DLC is a single half-duplex data stream between two users.

NEW APPLICATIONS
Many attractive new applications are emerging that can be transported over frame relay. Two applications, which today are garnering a lot of attention, are voice and video over frame relay.

Voice Over Frame Relay
Voice over frame relay is a rapidly maturing technology with primary interest being generated by customers looking to drive down the costs of their voice traffic while consolidating data networking costs. The voice FRAD technology has matured rapidly during the last two years while the cost of the associated hardware and software has dropped considerably. It is becoming very attractive to companies who look to utilize spare frame relay bandwidth, which has already been paid for to support basic voice requirements.

Companies are now using this for point-to-point nonmissioncritical voice applications, especially on routes where the round-trip delay is minimal and the PSTN tariffs are prohibitive.

Video Over Frame Relay
There has also been a lot of recent press coverage about new video over frame relay capabilities from the most innovative hardware and software manufacturers — further proof that frame relay is not just seen as an IP or basic data transport mechanism.

Stepping Stone To ATM?
Coupled with bandwidth capabilities up to 45 Mbps and support for multimedia applications, frame relay is proving an important stepping stone to newer technologies, such as ATM. In fact, with the great capabilities and bandwidths being offered by ATM, many companies may find that frame relay meets all of their medium- and long-term requirements, at least until international bandwidth becomes more affordable and their bandwidth needs have grown beyond frame relay. While ATM promises capabilities from 45 Mbps to 1.2 Gbps, this bandwidth is really only necessary in campus or LAN environments, and customers will not usually require such speeds in their WAN. In fact, if this much bandwidth was required, the probability is that the tariffs alone would be a strong deterrent.

UNIQUE CHALLENGES
We have seen that frame relay offers an ideal migration path from both leased-line solutions and from X.25, but for many companies, the real bene-fit is that they can focus on their core business while freeing valuable resources.

The unique challenge to these companies is to forecast the growth and requirements of their customers and colleagues as network sizing becomes important. With frame relay reports, performance and traffic statistics are reported to all customers. This makes it easy to see which network links are being used, and how. Recommendations on network sizing, in fact, are all part of the managed service.

The introduction of new services such as frame relay will encourage employees and customers to use the network. Coping with growth should not be a problem, as PVCs can be expanded via software reconfiguration, provided the customer access circuit has enough bandwidth to cope with the increase. If not, the customer will require an access circuit upgrade from the local service provider, which may not take a long time, but may prove a little inconvenient in some parts of the world.

FRAME RELAY SAVINGS
The key advantage to frame relay is that it is designed to be priced at between 10 percent and 50 percent cheaper than leased-line solutions, which, for many companies is reason enough to make use of frame relay. Managed FRAD service not only consolidates multi-protocol traffic types through a single access device into a single line connected to the frame relay service, but is capable of replacing many lower speed multi-drop lines, the type one would expect to encounter in a branch networking environment.

At the same time, the customer benefits from a high-speed service for a fraction of the original cost. A FRAD is the only new technology required — the cluster controllers and other terminals currently in use do not need to be replaced unless, of course, they have come to the end of their useful life and are going to be changed anyway. Replacement costs are minimal and, since the company will be using a managed service, there are no hardware investments to make. The components of the service can be charged as a combined monthly charge covering all the elements.

At the same time, freeing human resources to work on other projects enables savings while increasing efficiency.

FRAME RELAY RESILIENCE
Frame relay, like X.25, is a very secure and reliable medium ideally suited for high availability. Unlike pointtopoint routing associated with leased-line solutions, frame relay benefits from diverse routing because of the meshed network architecture built into its backbone.

ALTERNATIVE TECHNOLOGIES
We have already considered two major alternatives: leased lines, which tend to be customer managed, and X.25, which although highly available, is generally limited to access speeds of 64 kbps.

The Internet is an alternative, but is not ideal for mission-critical business applications due to the fact that there are no inherent guarantees that messages will be delivered, there are no expected response times, and possibilities exist for network failures that may go unaccounted for. A common complaint is network congestion — there are too many people trying to use the Internet for too many applications. ISDN is another competitive solution especially in markets where the tariffs are favorable. But, for international networking, the break-even point comes when it becomes more economical to use flat-top tariffed frame relay service.

With lead times now very acceptable in most countries, frame relay networks can be deployed quickly, upgraded quickly, and fixed quickly through local and global help desks. Performance reports assure customers that networks are performing to predetermined service levels, and also give guidance on network sizing.

ATM is still a ways off in the WAN because the bandwidth is not priced attractively. Frame relay, with evergrowing multimedia support and increased access speeds, will be around for a long while to come, even if some companies only view it as a stepping stone. For the majority, it will offer far greater functionality and more capability than they will ever need.

Nick Brooks is product manager, Broadband Services, at EQUANT Network Services, a provider of highquality voice and data services to multinational companies over the world’s largest international global communications network. For more information, visit the company’s Web site at www.equant.com.