Answer to Question #273362 in Computer Networks for may

Question

Briefly EXPLAIN X.25 and Frame Relay protocols, their protocol layers and equipment used

Answer 1

X.25

X.25 is a protocol suite defined by ITUT for packet-switched communication over a WAN (Wide Area Network).Currently it's used in ATM and credit card verification networks. This allows multiple logical channels to use the same physical line. You can also exchange data between end devices with different communication speeds.

It has three protocol layers

Physical layer

It defines the physical, electrical, and functional properties that form the interface between the computer terminal and the connection to the packet-switched node X.21. Physical implementers are often used for links.

Data link layer

Contains procedures to access links for exchanging data over the link. It uses the LAPB frame (Link Access Procedure Balanced).

Packet layer

This layer defines the format of the data packet and the procedure for managing and transmitting the data packet.

Equipment used

• X.21 implementer
• DTE − Data Terminal Equipment
• DCTE − Data Circuit Terminating Equipment

Frame Relay Protocol

Frame Relay is a packet-switched communication service from the local area network (LAN) to the backbone and wide area networks. It operates at two levels: the physical layer and the data link layer. It supports all standard physical layer protocols. This is mainly implemented at the data transfer channel level.

Equipment used

• DTE − Data Terminal Equipment
• DCTE: − Data Circuit Terminating Equipment