Frame Relay

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Introduction of Frame Relay

The concept of Frame Relay was initially designed for transmission across Integrated Services Digital Network(ISDN) infrastructure i.e. Frame Relay originated as an extension of integrated services digital network (ISDN).

Frame Relay is a standard or technology applied in a wide area network (WAN) that specifies the physical and data link layers of digital telecommunications channels using a packet-switching methodology.

These techniques transmit data in the form of frames(a variable-size data unit).
This technology provides a telecommunication service in a cost-efficient way for data transmission between local area networks (LANs) and between end-points in a wide area network (WAN).
The Frame Relay network handles the transmission over a frequently changing path transparent to all end-users with extensively used WAN protocols.
It has a very simple structure and hence is less expensive than leased lines service so it is more popular.
Due to the advent of Ethernet, VPN, Broadband DSL, etc. technology, it has now become less popular in recent times.
It is a fast packet-switching technology for data transmission.

Each Frame Relay consists of the following fields:-

Flag Field: The flag is used to indicate the beginning and end of the frame with a unique pattern.
Address Field: Each address field may occupy either octet 2 to 3, octet 2 to 4, or octet 2 to 5, depending on the range of the address in use.
Information Field: It defines the maximum information field size that a host can pack into a frame i.e. at least 262 octets but it recommends that the network support the maximum value of at least 1600 octets in order to avoid the need for segmentation and reassembling by end-users.
Frame Check Sequence (FCS) Field: This error detection mechanism is used in the Frame Relay technique that uses the cyclic redundancy check (CRC) method.

It is mainly used to connect LANs with major backbones(to interconnect diverse networks), as well as on public WANs and also in private network environments with leased lines.
It switches create virtual circuits to connect remote LANs to a WAN.