Configure Quality of Service
179
S350 Series 8-Port Gigabit Ethernet Smart Managed Pro Switch Models GS308T and GS310TP
The traffic class is the hardware queue for a port. Higher traffic class values indicate a
higher queue position. Before traffic in a lower queue is sent, it must wait for traffic in
higher queues to be sent.
The allowed Per Hop Behavior (PHBs) values, besides other DSCP experimental values,
are as follows:
• Class Selector (CS) PHB. These values are based on IP precedence.
• Assured Forwarding (AF) PHB. These values define four main levels to sort and
manipulate some flows within the network.
• Expedited Forwarding (EF) PHB. These values are used to prioritize traffic for
real-time applications. In many situations, if the network exceeded traffic and you
need some bandwidth guaranteed for an application, the EF traffic must receive this
rate independently of the intensity of any other traffic attempting to transit the node.
The Other DSCP Values (Local/Experimental Use) section allows you to set non-default
values for advanced settings.
7. Click the Apply button.
Your settings are saved.
Manage 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.
To Next Page
Loading...
Need help?
General
