Operation Manual – QoS-QoS Profile
H3C S3100 Series Ethernet Switches
Chapter 1 QoS Configuration
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are critical for videoconference and VoD. As for other applications, such as transaction
processing and Telnet, although bandwidth is not as critical, a too long delay may cause
unexpected results. That is, they need to get serviced in time even if congestion occurs.
Newly emerging applications demand higher service performance from IP networks. In
addition to simply delivering packets to their destinations, better network services are
demanded, such as allocating dedicated bandwidth, reducing packet loss ratio,
avoiding congestion, regulating network traffic, and setting priority of the packets. To
meet those requirements, the network should be provided with better service capability.
1.1.4 Major Traffic Control Techniques
Figure 1-1
End-to-end QoS model
Traffic classification, traffic policing, traffic shaping, congestion management, and
congestion avoidance are the foundations for a network to provide differentiated
services. Mainly they implement the following functions.
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Traffic classification identifies traffic based on certain matching rules. It is a
prerequisite for differentiated services and is usually applied in the inbound
direction of a port.
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Traffic policing confines traffic to a specific specification and is usually applied in
the inbound direction of a port. You can configure restriction or penalty measures
against the exceeding traffic to protect carrier benefits and network resources.
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Traffic shaping adapts output traffic rate usually to the input capability of the
receiving device to avoid packet drop and port congestion. Traffic shaping is
usually applied in the outbound direction of a port.
z
Congestion management handles resource competition during network
congestion. Generally, it puts packets into queues first, and then schedules the
packets with a certain algorithm. Congestion management is usually applied in the
outbound direction of a port.
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Congestion avoidance monitors the use of network resources and drops packets
actively when congestion reaches certain degree. It relieves network load by
