Question

Which among the following is true about the explicit congestion network?

(a) Explicit congestion notification is an extension of the data link layer and network layer

(b) Explicit congestion notification is an extension of transport and network layer

(c) Explicit congestion notification is an extension of transport and data link layer

(d) Explicit congestion notification is an extension of the physical and data link layer

I got this question during an interview.

My question comes from Next Generation Wireless Network topic in division Next Generation Wireless Network of Cognitive Radio

Answer 1

Right option is (b) Explicit congestion notification is an extension of transport and network layer

To explain I would say: Explicit congestion notification informs about network congestion to end devices without dropping packets. It is possible only when the end devices and the underlying infrastructure support ECN. The procedure involves marking a bit in the IP header to indicate upcoming congestion.