Netgear GSM4248P User Manual - Page 464

AV Line of Fully Managed Switches M4250 Series Main User Manual Table 133. CoS Interface Queue Drop Precedence Status (Continued) Field WRED Maximum Threshold WRED Drop Probability Scale Description The WRED maximum queue threshold value. The WRED packet drop probability value. Differentiated Services 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 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. If congestion occurs, packets might be delayed, sent sporadically, or dropped. For typical Internet applications, such as email and file transfers, a slight degradation in service is acceptable and in many cases unnoticeable. However, any degradation of service can negatively affect applications with strict timing requirements, such as voice and multimedia. Defining DiffServ To use DiffServ for QoS, you must first define the following categories and their criteria: 1. Class: Create classes and define class criteria. 2. Policy: Create policies, associate classes with policies, and define policy statements. 3. 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. Note the following about the DiffServ process: • Packets are filtered and processed based on defined criteria. The filtering criteria is defined by a class. The processing is defined by a policy's attributes. Policy attributes Configure Quality of Service 464 Main User Manual