COMP 445 Study Guide - Midterm Guide: Queuing Delay, Message Queue, Propagation Delay

• School: Concordia University
• Department: Computer Sci.
• Course: COMP 445
• Professor: aimanhanna

Document Summary

The ne twork edge packet transmission delay = time needed to transmit l-bit packet into link = l(bits)/r(bits/sec) packets of length l transmission rate r. The ne twork core hosts break application-layer message into packets. Packet-switching: store and forward takes l/r seconds to transmit (push-out) entire packet must arrive at router before it can be transmitted end-to-end delay = 2l/r assuming no propagation delay. Packet-switching: queueing delay, loss packets will queue, wait to be transmitted packets can be dropped if memory buffer fills up routing: determines source-destination route taken by packets forwarding: move packets from router"s input to appropriate router output. Circuit-switching dedicated end-to-end resources between source and destination no sharing common in traditional phone networks. De la y, los s , throughput loss and delay occur because of packet queues in router buffers arrival rate to link temporarily exceeds output link capacity packets queue, wait for turn.