Packet Switching

Is a method of transmitting data in a network via small units called Packets that contain a division of the data.

An alternative to this is Circuit Switching.

As the packets travel from one Node to another they can experience multiple types of delay:

• Processing Delay
• Queuing Delay
• Transmission Delay
• Propagation Delay

The total nodal delay is therefore

$$d_{\text{nodal}}=d_{\text{processing}}+d_{\text{queuing}}+d_{\text{transmission}}+d_{\text{propagation}}$$

The accumulation of node delays on $N$ identical Communication Links and $N-1$ identical Routers result in the end-to-end delay (assuming no Congestion such that there is no Queuing Delay)

$$d_{\text{end-end}}=N(d_{\text{processing}}+d_{\text{transmission}}+d_{\text{propagation}})$$