Which of the following is not a congestion policy at network layer?

Explanation

Flow control is a function of the data link layer and transport layer, not a network layer congestion policy. Flow control manages the rate of data transmission between two nodes to prevent a fast sender from overwhelming a slow receiver. Network layer congestion policies are: (1) Virtual circuits vs datagram inside the subnet (2) Packet queueing and service policy (3) Packet discard policy (4) Routing algorithm (5) Packet lifetime management.