The assignment requirement is to realize a reliable transmission simulation program according to rdt 3.0 protocol. The program was given by the teacher. Of course, the program is incomplete and needs to be modified and perfected by itself. Altbit.c is the code file that needs to be changed, and all other files are correct. 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. Programming Assignment 5: Implementing a Reliable Transport Protocol. In this laboratory programming assignment, you will be writing the sending and receiving transport-level code for implementing a simple reliable data transfer protocol. There are two versions of this lab, the Alternating-Bit-Protocol version and the Go-Back-N version. In this section, we present an alternating bit protocol with a sender and a receiver processes that are subject to message loss faults. Using the synthesis method presented in 1, we synthesize an alternating bit protocol that is nonmasking faulttolerant; i.e., when faults occur the program guarantees recovery to its invariant. Programming Languages Models -Abstract Programs. Alternating bit protocol in page 8 is capable of delivering data without duplication and in the right order.
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.
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]
See also[edit]
See Full List On Github.com
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.
Clarke’s Model-checking Flavio Lerda As Part Of Ed ...
- 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.