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Key Points. congestion occurs when number of packets traveling throught a network approaches capacitythe lack of flow control mechanisms built into ATM and frame relay protocols makes congestion control difficultATM networks establish a traffic contract with each userATM networks monitor the cell
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1. William StallingsData and Computer Communications8th Edition Chapter 13
Congestion in Data Networks
2. Key Points congestion occurs when number of packets traveling throught a network approaches capacity
the lack of flow control mechanisms built into ATM and frame relay protocols makes congestion control difficult
ATM networks establish a traffic contract with each user
ATM networks monitor the cell flow from each incoming source and may discard or label cells that exceed the agreed traffic flow
3. What Is Congestion? Congestion occurs when the number of packets being transmitted through the network approaches the packet handling capacity of the network
Congestion control aims to keep number of packets below level at which performance falls off dramatically
Data network is a network of queues
Generally 80% utilization is critical
Finite queues mean data may be lost
4. Queues at a Node