My teacher has assigned us to program Dijkstra's token termination algorithm in Promela. Here is the algorithm:
"Every node maintains a counter c. Sending a message increases c by one; the receipt of a message decreases c by one. The sum of all counters thus equals the number of messages pending in the network. When node 0 initiates a detection probe, it sends a token with a value 0 to node N-1. Every node i keeps the token until it becomes passive; it then forwards the token to node i-1 increasing the token value by c. Every node and also the token has a color (initially all white). When a node receives a message, the node turns black. When a node forwards the token, the node turns white. If a black machine forwards the token, the token turns black; otherwise the token keeps its color. When node 0 receives the token again, it can conclude termination, if node 0 is passive and white, the token is white, and the sum of the token value and c is 0. Otherwise, node 0 may start a new probe."
I somewhat get the idea, but I am having trouble really understanding what is going on. If someone could help explain exactly what the algorithm is doing step-by-step, that would be great. Also, while I don't want anyone writing the code for me, any tips on how to get started would be helpful.
