3com S7906E 설치 설명서

 

1-1 

 

The S7900E Series Ethernet Switches are distributed devices supporting Intelligent Resilient 

Framework (IRF). Two S7900E series can be connected together to form a distributed IRF device. If an 

S7900E series is not in any IRF, it operates as a distributed device; if the S7900E series is in an IRF, it 

operates as a distributed IRF device. For introduction of IRF, refer to IRF Configuration in the System 

Volume. 

 

This chapter covers the following topics: 

z 

z 

z 

QoS Techniques Overview 

For network traffic, the Quality of Service (QoS) involves bandwidth, delay, and packet loss rate during 

traffic forwarding process. In a network, you can improve the QoS by guaranteeing the bandwidth, and 

reducing the delay, jitter, and packet loss rate.  

The network resources are always scarce. QoS requirements exist on any occasion where traffic flows 

contend for network resources. QoS is a relative concept for traffic flows, that is, guaranteeing QoS for 

a certain traffic flow may damage QoS of other traffic flows. For example, in the case of fixed bandwidth, 

if a traffic flow gets more bandwidth, the other traffic flows will get less bandwidth and may be affected. 

Therefore, the network administrator should reasonably plan and allocate network resources based on 

the characteristics of various traffic flows, thus utilizing the network resources effectively.  

The following part introduces the QoS service models, and some mature QoS techniques used most 

widely. Using these techniques reasonably in the specific environments, you can improve the QoS 

effectively.  

This section covers three typical QoS service models:  

z 

Best-effort service 

z 

Integrated service (IntServ) 

z 

Differentiated service (DiffServ)