The Alternating bit protocol is a form of communication protocol used in computer networks to ensure the reliable transmission of data between two entities, typically referred to as the sender and receiver. This protocol employs a simple approach to deal with potential issues such as packet loss, errors, and out-of-order delivery that might arise during data transmission.
In this protocol, the sender divides the data into small packets, each assigned with a unique sequence number. The sender then transmits the packets to the receiver one at a time, alternating between two states: sending a packet with the current sequence number and waiting for an acknowledgment (ACK) from the receiver, or resending the same packet if an acknowledgment is not received within a timeout period.
Upon receiving a packet, the receiver verifies the sequence number, checks for errors, and sends back an acknowledgment to the sender. If the received packet is error-free and in the expected sequence order, the receiver sends an ACK with the next expected sequence number. Otherwise, it discards the packet and sends an ACK for the previously successfully received packet.
This alternating process continues until all packets are successfully transmitted and acknowledged. The protocol ensures reliability by retransmitting packets when necessary, confirming their successful receipt, and reacting appropriately to out-of-order or duplicate packets.
The Alternating bit protocol provides a simple yet effective mechanism for achieving reliable communication between two entities in a network, commonly used in scenarios where transmission errors are likely to occur, such as wired or wireless connections where signal interference can affect data integrity.
