Netgear M5300-28G-POE+ (GSM7228PSv1h2) - 12-Port Managed Gigabit Switch Softwarehandbuch

The QoS feature contains Differentiated Services (DiffServ) support that allows traffic to be 
classified into streams and given certain QoS treatment in accordance with defined per-hop 
behaviors. 

Standard IP-based networks are designed to provide best effort data delivery service. Best 
effort service implies that the network delivers the data in a timely fashion, although there is 
no guarantee. During times of congestion, packets might be delayed, sent sporadically, or 
dropped. For typical Internet applications, such as email and file transfer, a slight degradation 
in service is acceptable and in many cases unnoticeable. Conversely, any degradation of 
service has undesirable effects on applications with strict timing requirements, such as voice 
or multimedia.

To use DiffServ for QoS, you must first define the following categories and their criteria:

Class - Create classes and define class criteria.

Policy - Create policies, associate classes with policies, and define policy statements.

Service - Add a policy to an inbound interface.

Packets are classified and processed based on defined criteria. The classification criteria are 
defined by a class. The processing is defined by a policy's attributes. Policy attributes can be 
defined on a per–class instance basis, and it is these attributes that are applied when a 
match occurs. A policy can contain multiples classes. When the policy is active, the actions 
taken depend on which class matches the packet.

Packet processing begins by testing the class match criteria for a packet. A policy is applied 
to a packet when a class match within that policy is found.

The DiffServ Wizard enables DiffServ on the switch by creating a traffic class, adding the 
traffic class to a policy, and then adding the policy to the ports that you select. The DiffServ 
Wizard does the following:

Creates a DiffServ Class and defines match criteria used as a filter to determine if 
incoming traffic meets the requirements to be a member of the class.

Sets the DiffServ Class match criteria based on Traffic Type selection as follows:

Drop Precedence Level

The drop precedence level. 

WRED Minimum Threshold

The weighted RED minimum queue threshold value.

WRED Maximum Threshold

The weighted RED maximum queue threshold value. 

WRED Drop Probability Scale

The packet drop probability value.