Application Scenarios for Congestion Avoidance and Congestion Management
Congestion Management
Congestion management is often deployed in QoS applications to schedule different services based on priorities
On an enterprise network, when multiple services compete for the same resources (such as the bandwidth and buffer), traffic congestion may occur and high-priority services may be not processed in a timely manner. Packets can be sent to different queues according to the priority mapping result, as shown in Figure 6-11. Different scheduling modes are set in the outbound direction to implement differentiated services.
Congestion Avoidance
When congestion occurs or aggravates, congestion avoidance discards low-priority packets to relieve network overload and ensure forwarding of high-priority packets.
As shown in Figure 6-12, users in different LANs may obtain data from the same server, so data exchanged between users and the server passes the WAN. Because WAN bandwidth is lower than LAN bandwidth, congestion may occur on the edge device between the WAN and LANs. Congestion avoidance can be configured on the edge device to discard low-priority packets such as data packets, reducing network overload and ensuring forwarding of high-priority services.
