Frame
Relay:
Frame relay is a telecommunication service designed for
cost-efficient data transmission for intermittent traffic between
local area networks (LANs) and between end-points in a wide area
network (WAN). Frame relay puts data in a variable-size unit called
a frame and leaves any necessary error correction (retransmission of
data) up to the end-points, which speeds up overall data
transmission. For most services, the network provides a permanent
virtual circuit (PVC), which means that the customer sees a
continuous, dedicated connection without having to pay for a
full-time leased line, while the service provider figures out the
route each frame travels to its destination and can charge based on
usage. An enterprise can select a level of service quality -
prioritizing some frames and making others less important. Frame
relay is provided on fractional T-1 or full T-carrier system
carriers. Frame relay complements and provides a mid-range service
between ISDN, which offers bandwidth at 128 Kbps, and Asynchronous
Transfer Mode (ATM), which operates in somewhat similar fashion to
frame relay but at speeds from 155.520 Mbps or 622.080 Mbps.
Frame relay is based on the older X.25 packet-switching
technology which was designed for transmitting analog data such as
voice conversations.
Unlike X.25 which was designed for analog signals, frame relay is
a fast packet technology, which means that the protocol does not
attempt to correct errors.
When an error is detected in a frame, it is simply "dropped."
(thrown away). The end points are responsible for detecting and
retransmitting dropped frames. (However, the incidence of error in
digital networks is extraordinarily small relative to analog
networks.)
Frame relay is often used to connect local area networks with
major backbones as well as on public wide area networks and also in
private network environments with leased lines over T-1 lines. . It
requires a dedicated connection during the transmission period. It's
not ideally suited for voice or video transmission, which requires a
steady flow of transmissions. However, under certain circumstances,
it is used for voice and video transmission.
Frame relay relays packets at the Data Link layer of the Open
Systems Interconnection (OSI) model rather than at the Network
layer. A frame can incorporate packets from different protocols such
as Ethernet and X.25. It is variable in size and can be as large as
a thousand bytes or more.
Frame Relay Service Provided
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