Alternating Bit Protocol C Program

GitHub - Ankeshni/Simulation-of-transport-Layer-protocols-in-c
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Alternating Bit Protocol C Program
Alternating Bit Protocol C Programs

ICS 451 Assignment 6: Alternating Bit Protocol Assigned February 24th, to be completed by March 3rd. Turn in this exercise by e-mailing to jmoroney@hawaii.edu all your code. You may do this assignment in groups of up to three. Your team cannot include anyone that was on your team in Assignment 5. 2 The alternating bit protocol The alternating bit protocol, or ABP, is used to transmit messages on a lossy channel, that is, a channel that can lose some of the messages it receives be-fore delivering them at the other end. According to ABP, a bit is attached to each packet of information sent through the channel. The sender must keep on. More behavioural equivalences. This module elaborates on the equivalences provided earlier. It is shown how it can be applied, especially to the alternating bit protocol. Furthermore, a number of additional equivalences are introduced. The alternating bit protocol 13:18. The output should be similar in form to the output for the alternating bit protocol, but you should see a more efficient transfer of data. Documentation for Provided Classes. The classes that you will be working with are extensively documented. The documentation has been compiled into HTML web pages using the javadoc program.

Alternating bit protocol (ABP) is a simple network protocol operating at the data link layer (OSI layer 2) that retransmits lost or corrupted messages using FIFO semantics. It can be seen as a special case of a sliding window protocol where a simple timer restricts the order of messages to ensure receivers send messages in turn while using a window of 1 bit.^[1]

Design[edit]

Messages are sent from transmitter A to receiver B. Assume that the channel from A to B is initialized and that there are no messages in transit. Each message from A to B contains a data part and a one-bit sequence number, i.e., a value that is 0 or 1. B has two acknowledge codes that it can send to A: ACK0 and ACK1.

When A sends a message, it resends it continuously, with the same sequence number, until it receives an acknowledgment from B that contains the same sequence number. When that happens, A complements (flips) the sequence number and starts transmitting the next message.

GitHub - Ankeshni/Simulation-of-transport-Layer-protocols-in-c

When B receives a message that is not corrupted and has sequence number 0, it starts sending ACK0 and keeps doing so until it receives a valid message with number 1. Then it starts sending ACK1, etc.

This means that A may still receive ACK0 when it is already transmitting messages with sequence number one. (And vice versa.) It treats such messages as negative-acknowledge codes (NAKs). The simplest behaviour is to ignore them all and continue transmitting.

The protocol may be initialized by sending bogus messages and acks with sequence number 1. The first message with sequence number 0 is a real message.

A variant of this protocol, introduced by Philips, is called Bounded Retransmission Protocol (BRP). Unlike ABP, BRP deals with sequence numbers of datum in the file and interrupts transfer after fixed number of retransmissions for a datum.^[2]

History[edit]

An Alternating Bit Protocol was used by the ARPANET and the European Informatics Network.^[3]

References[edit]

^Tel, Gerard (2000). Introduction to distributed algorithms. Cambridge. p. 85. ISBN0521794838.
^'TreX's Examples -- Bounded Retransmission Protocol'. www.irif.fr.
^Davies, Donald Watts (1979). Computer networks and their protocols. Internet Archive. Chichester, [Eng.] ; New York : Wiley. pp. 206.

This article is based on material taken from the Free On-line Dictionary of Computing prior to 1 November 2008 and incorporated under the 'relicensing' terms of the GFDL, version 1.3 or later.

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