IPQoS features enable Internet service providers (ISPs) and application service providers (ASPs) to offer different levels of network service to customers. These features enable individual companies and educational institutions to prioritize services for internal organizations or for major applications.
If your organization is an ISP or ASP, you can base your IPQoS configuration on the service-level agreement (SLA) that your company offers to its customers. In an SLA, a service provider guarantees to a customer a certain level of network service that is based on a price structure. For example, a premium-priced SLA might ensure that the customer receives highest priority for all types of network traffic 24 hours per day. Conversely, a medium-priced SLA might guarantee that the customer receives high priority for email only during business hours. All other traffic would receive medium priority 24 hours a day.
If your organization is an enterprise or an institution, you can also provide quality-of-service features for your network. You can guarantee that traffic from a particular group or from a certain application is assured a higher or lower degree of service.
You implement quality of service by defining a quality-of-service (QoS) policy. The QoS policy defines various network attributes, such as customers' or applications' priorities, and actions for handling different categories of traffic. You implement your organization's QoS policy in an IPQoS configuration file. This file configures the IPQoS modules that reside in the Oracle Solaris kernel. A host with an applied IPQoS policy is considered an IPQoS-enabled system.
Your QoS policy typically defines the following:
Discrete groups of network traffic that are called classes of service.
Metrics for regulating the amount of network traffic for each class. These metrics govern the traffic-measuring process that is called metering.
An action that an IPQoS system and a Diffserv router must apply to a packet flow. This type of action is called a per-hop behavior (PHB).
Any statistics gathering that your organization requires for a class of service. For example, traffic that is generated by a customer or particular application.
When packets pass to your network, the IPQoS-enabled system evaluates the packet headers. The action that the IPQoS system takes is determined by your QoS policy.
Tasks for designing the QoS policy are described in Planning the Quality-of-Service Policy.