Question: The three-node network of Fig. contains only one virtual circuit from node 1 to 3, and uses node-by-node windows. Each packet transmission on link (1,2) takes 1 sec, and on link (2.3) takes 2 sec: processing and propagation delay is negligible. Permits require 1 sec to travel on each link. There is an inexhaustible supply of packets at node 1. The system starts at time 0 with W permits at node 1, W permits at node 2, and no packets stored at nodes 2 and 3. For W = 1, find the times, from 0 to 10 sec at which a packet transmission starts at node 1 and node 2. Repeat for W = 2.
