8. Delays and Links

Delays represent the time required for a packet to traverse a link. A special form of this object (``dynamic link'') also captures the possibility of a link failure. The amount of time required for a packet to traverse a link is defined to be $s/b + d$ where $s$ is the packet size (as recorded in its IP header), $b$ is the speed of the link in bits/sec, and $d$ is the link delay in seconds. The implementation of link delays is closely associated with the blocking procedures described for Queues in Section7.1.1.