2.5 Delay, Loss, & Throughput in Packet-Switched Networks
What is end-to-end delay?
End-to-end delay or one-way delay (OWD) refers to the time taken for a packet to be transmitted across a network from source to destination.
What are the four types of delay that a packet may encounter at each hop (i.e. at each router)?
Transmission Delay, Propagation Delay, Queing Delay, End-to-end delay
What is the traceroute tool? What does it measure?
traceroute is a computer network diagnostic tool for displaying the route (path) and measuring transit delays of packets across an Internet Protocol (IP) network.
What is the bottleneck link?
bottleneck link for a given data flow is a link that is fully utilized (is saturated) and of all the flows sharing this link,
What is the difference between transmission delay and propagation delay?
Transmission delay: is a delay based on how long it takes to send the signal down the transmission line. Propagation Delay: the time that a packet takes to move in the link, which depends on the speed of light.
What is throughput?
In data transmission, network throughput is the amount of data moved successfully from one place to another in a given time period, and typically measured in bits per second (bps), as in megabits per second (Mbps) or gigabits per second (Gbps).
What causes queuing delay?
Queuing delay is a delay based on how long the packet has to sit around in the router. Quite often the wire is busy, so we can't transmit a packet immediately. In these cases, the packet sits, ready to go, in a queue. These delays are almost entirely defined by the amount of traffic on the network (often queuing delay is the only traffic dependent part of the puzzle!). The more traffic there is, the more likely a packet finds itself stuck behind another packet in the queue, just sitting in memory, waiting.
What is the ping tool? What does it measure?
RTT is typically measured using a... . ping — a command-line tool that bounces a request off a server and calculates the time taken to reach a user device
