Frame Relay

Frame Relay:

It is a standardized wide area network technology that specifies the physical and logical link layers of digital telecommunications channels using a packet switching methodology. Originally designed for transport across integrated services digital network (ISDN) infrastructure, it may be used today in the context of many other network interfaces.

Network providers commonly implement Frame Relay for voice (VoFR) and data as an encapsulation technique, used between local area networks (LANs) over a wide area networks (WAN). Each end-user gets a private line (or leased line) to a Frame Relay node. The Frame Relay network handles the transmission over a frequently-changing path transparent to all end-users.

Frame Relay has become one of the most extensively-used WAN protocols. Its cheapness (compared to leased lines) provided one reason for its popularity. The extreme simplicity of configuring user equipment in a Frame Relay network offers another reason for Frame Relay's popularity.

Frame Relay began as a stripped-down version of the X.25 protocol, releasing itself from the error-correcting burden most commonly associated with X.25. When Frame Relay detects an error, it simply drops the offending packet. Frame Relay uses the concept of shared-access and relies on a technique referred to as "best-effort", whereby error-correction practically does not exist and practically no guarantee of reliable data delivery occurs. Frame Relay provides an industry-standard encapsulation utilizing the strengths of high-speed, packet-switched technology able to service multiple virtual circuits and protocols between connected devices, such as two routers.

Frame:

When Frame Relay was developed, the important part of the data−carrying capacity was the use of the frame to carry the traffic and not have the same overhead as an older technology (such as X.25). The frame was filled with data as necessary, but it handled the speed and throughput via the high−speed communications and lower overhead.

Frame relay vs OSI:

Frame Relay works at the data link layer to reduce the overhead associated

with the movement of data across the wide area. Because we refer to Frame Relay as a WAN

technology, it is natural that the protocols will work with the improvements made in the network over

the past decades.

In the older days, data was shipped across the layer three protocols (such as X.25) to assure the

reliability and integrity of the data.The X.25 protocol worked at layer three.The overhead associated with the transmission and reception of the data on the X.25 networks was inordinate. To facilitate better data throughout and eliminate some of the overhead, Frame Relay was developed. 

• The networks were now improved through the mass deployment of fiber−based networking technologies and the use of SONET protocols.
• The networking st rategies of  many end users were based on  router   technologies and LAN−to−WAN communications instead of the older terminal−to−host inter communications.

These two changes actually revamped the way we communicate. No longer did we have to use a

timing   relationship,  as in the older data networks. Any form of data transmission could be

accommodated across the newer improved techniques and protocols

With this comparison in mind, one will note that the Layer 2 protocol (in this case, Frame Relay)

eliminates some of the overhead associated with the transmission of data. The need for network

addressing using Layer 3 is reduced because many of the link architectures are based on

point−to−point circuits or private networking techniques.

Frame Relay Speed:

Carriers' Implementation of IP−Enabled Frame Relay:

Carriers are now offering IP−enabled services, enabling a customer to use an existing Frame Relay

access link to tap into a connection less Multiprotocol Label Switching (MPLS)−based IP backbone

or a private IP network. The primary benefit is that achieving mesh connectivity within a customer's

VPN requires just a single "access" PVC from each remote site.

Frame Relay vs IP:

Source:


www.wikipedia.com
Broadband Telecommunications Handbook second edition by Regis J. "BUD" BATES