Qtech QSW-2910-09T-POE-AC/DC [96/212] Chapter 7 qos configuration

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Chapter 7 QOS Configuration

7.1 Brief introduction of QOS

In traditional packet network, all packets are equal to be handled. Each switch and router

handles packet by FIFO to make best effort to send packets to the destination and not to

guarantee the transmission delay and delay variation.

With the fast development of computer network, the requirement of network is higher. More

and more voice, image and important data which are sensitive about bandwidth, delay and

jittering transferred through network, which greatly enrich network service resources and the

requirement of quality of service is higher for the network congestion. Now, Ethernet becomes

the leading technology in every independent LAN, and many LAN in the form of Ethernet have

become a part of internet. With the development of Ethernet technology, Ethernet connecting

will become one of main connecting for internet users. To realize end-to-end QoS solution has

to consider the service guarantee of Ethernet QoS, which needs Ethernet device applies to

Ethernet technology to provide different levels of QoS guarantee for different types of service

flow, especially the service flow highly requiring delay and jitter.

1. Flow

Flow is traffic which means all packets through switch.

2. Traffic classification

Traffic classification means adopting certain regulation to recognize packet with some features.

Clasification rule means the filtration regulation configured by the administrator according to

managing need which can be simple, such as realizing flow with the feature of different priority

according to the ToS field of IP packet head and can be complicated, such as information of

integrated link layer (layer 2), network layer (layer 3), transmission layer (layer 4), such as

MAC address, IP protocol, source address, destination address or application program

interface number to classify packet. General classification is limited in the head of

encapsulation packet. Use packet content to be classification standard is singular.

3. Access control list

To classify flow is to provide service distinctively which must be connected resource

distributing. To adopt which kind of flow control is related to the stage it is in and the current

load of the network. For example: monitor packet according to the promised average speed

rate when the packet is in the network and queue scheduling manage the packet before it is

out of the node.

4. Packet filtration

Packet filtration is to filtrate service flow, such as deny, that is, deny the service flow which is