What is meant by network congestion?

Answer 1

When too many packets are present in a subnet, performance degrades. This situation is called Congestion.

Update:

In any network when there is too much the data traffic at a node that the network slows down or starts loosing data, it is known as network congestion. It degrades quality of service and also can lead to delays, lost data or e.g. dropped calls on a telephone network.

- Neeraj Sharma

when excess of data travels in a subnet or in node there will be a loss of data, this excess flow is know as network congestion.This demotes the performance in network e.g.improper delivery of fax

Answer 2

Congestion is a situation where a link is carrying so much data that it's quality deteriorates.

A network carrying data packets have two important measurable parameters:

i) Load: Load means the number of packets being carried by the network.

ii) Capacity: Capacity refers to the maximum number of packets that the network is able to carry.

When the load on the network becomes greater than the capacity of the network, congestion occurs.

The main causes of congestion are:-

A. Bad Retransmission policy: If we use bad retransmission policies like Go back N, the number of frames to be sent on occasion of a retransmission is increased, thus increasing the Load on the network thereby creating a probability of congestion.

B. Bad Acknowledgement Policy: The acknowledgement frames also put load on the network. Hence if each and every frame is acknowledged, probability of congestion increases.

Answer 3

causes are :

- too many hosts in a broadcast domain

- broadcast storms

- low bandwidth

Answer 4

Network congestion is when a link carries so much information that the quality of service slows down. Queuing delay or blocking of new connections are signs there is network congestion.