Question

What is processing delay? What is queuing delay? What is transmission delay? What ispropagation delay? Explain why a network system should be designed to have a traffic intensity of no greater than 1.

Answer 1

1: Processing Delay: This term is related to networking. We know that a router transmit the data in packet form So In networking the processing delay is the time that a router takes to process the packet header. This processing delay occur during performing complex encryption algorithm, Deep packet Inspection or during network address translation etc.

2: Queing Delay : This term is also used in networking. Queing delay is most often used in reference to routers. When a packets arrives at a router, they have to be processed and transmitted. A router can only process one packet at a time. If packets arrive faster than the router can process them such as in a burst transmission the router puts them into the queue,until it can get around to transmitting them. This queue is also called buffer.

Here is the exact defination..

"In packet switching queueing delay is the time the packets is assigned to a queue for transmission and the time it starts transmitting. During this time, the packet waits in a buffer to be serviced while other packet in the transmission queue are transmitted."

3: Transmission Delay: In networking most of the packet switched network use store and forward mechanism for packet transmission. So transmission delay is the amount of time it takes to push all the packets to the transmitting links.And this transmission delay is depends on the data rate of the links.

4: Propagation Delay: Propagation Delay is the time taken by the 1st bit of the packet to reach the receiver router. It can be calculated by dividing the distance between the two routers and the speed of propagation of the link.

The combination of these all delays is called Nodal Delay.

Why a network system should be designed to have a traffic intensity of no greater than 1.???

In Networking traffic intensity is a measure of the average occupancy of a server or resource during a specified period of time, normally in a busy hour.

Network system should be designed to have a traffic intensity of not greater than 1 because If traffic intensity is greater than one it means that the rate at which bits arrive exceeds the rate at which bits can be transmitted. Hence the Queuing delay will grow without bound under these circumstances as long as the traffic intensity stays the same. If the traffic intensity is less than one then the router can handle more average traffic.

Hence network system should be Designed so that the traffic intensity is no greater than 1.