zlociu / SWN-Token-Ring

Algorithm of token transport in unreliable token-ring topology

SWN-Token-Ring

An implementation of algorithm of token transport in unreliable token-ring topology.
Implementation in C# & F# in .NET 6 using async Tasks.
Works on Windows & Linux (tested on Windows 10 & Fedora 35).

How to run

C#

1. Go to folder where file .csproj exists.
2. Open cmd/terminal.
3. Type: dotnet run

F#

1. Go to folder where file .fsproj exists.
2. Open cmd/terminal.
3. Type: dotnet run

How algorithm works?

0. Initial conditions:
   • synchronous workflow
   • NO FIFO in communication (token value increase infinitely)
   • all messages are sent in one direction
   • communication channels can be unreliable but in finite time.
1. Only one process/thread which have token can do things (critical section).
2. Process (1) send token to next process. (e.g. 1 -> 2)
3. Process (2) get token, sends ack with token number.
4. Process (2) do things in its critical section and then sends token again (with bigger sequencial value e.g. +1).
   1. If process (1) didn't received ack for sent token in specified time (timeout), resend it.
   2. Process (1) will resending token until:
      • get ack OR
      • get newer token than it has.

Addition

Project was created for High Reliability Systems Lab course held by Institute of Computing Science, Poznań University of Technology.