Traffic control functions

Traffic control functions only apply to integrated service and are not specific to System i™ products.

You cannot see these terms used in the quality of service (QoS) interface, because the server cannot control external hardware. Outside a private network, the hardware needs to have the ability to handle general QoS requirements. The general router requirements for integrated service policies are discussed in the following section. It is suggested that you research general QoS concepts and prerequisites before implementing the policies.

To get the predictable results, you need to have the hardware that is enabled by ReSerVation Protocol (RSVP) along the traffic's path. Routers must have certain traffic control functions to use RSVP. This is often referred to as being RSVP-enabled or QoS-enabled. Remember that your operating system's role is either a client or a server. It cannot be used as a router at this time. Check with your network equipment manuals to verify that they can handle QoS requirements.

Traffic control functions include the following functions:

Packet scheduler

The packet scheduler manages the packet forwarding based on the information in the IP header. The packet scheduler ensures that the packet delivery corresponds to the parameters that you set in your policy. The scheduler is implemented at the point where packets are queued.

Packet classifier

The packet classifier identifies which packets of an IP flow receive a certain level of service based on the IP header information. Each incoming packet is mapped by the classifier into a specific class. All the packets that are classified in the same class receive the same treatment. This service level is based on the information that you provide in your policy.

Admission control

The admission control contains the decision algorithm that a router uses to determine whether there are enough routing resources to accept the requested QoS for a new flow. If there are not enough resources, the new flow is rejected. If the flow is accepted, the router assigns the packet classifier and scheduler to reserve the requested QoS. Admission control occurs in each router along the reservation path.

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Related concepts
QoS APIs