... protocols, and gateway-to-gateway protocols. Two routers that communicate directly with one another and are both part of the same autonomous system are said to be interior neighbors and are called ... Structure of the time stamp request and reply • Type 13 for time-stamp request and 14 for time-stamp reply message • Originate time-stamp Generated by sender and contains a time value identifying ... the gateways (routers)) and the destination node are all operating correctly. The structure of the request and reply are indicated below. Figure 6.39 ICMP echo request and reply The first...