GUARANTEE

typedef enum

{ 

    BestEffortService,

    ControlledLoadService,

    PredictiveService,

    GuaranteedService

} GUARANTEE;

Types

GuaranteedService

A service provider supporting guaranteed service implements a queuing algorithm which isolates the flow from the effects of other flows as much as possible, and guarantees the flow the ability to propagate data at the TokenRate for the duration of the connection. If the sender sends faster than that rate, the network may delay or discard the excess traffic. If the sender does not exceed TokenRate over time, then latency is also guaranteed. This service is designed for applications which require a precisely known quality of service but would not benefit from better service, such as real-time control systems.

PredictiveService

A service provider supporting predictive service guarantees the flow the ability to propagate data at the TokenRate for the duration of the connection. If the sender sends faster than that rate, the network may delay or discard the excess traffic. The delay limit is not guaranteed (occasional packets may take longer than specified), but is generally highly reliable. This service is designed for applications that can accommodate or adapt to some variation in service quality, such as video service.

ControlledLoadService

With this service, end-to-end behavior provided to an application by a series of network elements tightly approximates the behavior visible to applications receiving best-effort service "under unloaded conditions" from the same series of network elements. Thus, applications using this service can assume that:

  1.  A very high percentage of transmitted packets will be successfully delivered by the network to the receiving end-nodes. (Packet loss rate will closely approximate the basic packet error rate of the transmission medium).

  2.  Transit delay experienced by a very high percentage of the delivered packets will not greatly exceed the minimum transit delay experienced by any successfully delivered packet at the speed of light.

Note  This definition comes from the Internet Engineering Task Force (IETF).

BestEffortService

A service provider supporting best effort service, at minimum, takes the flow spec as a guideline and makes reasonable efforts to maintain the level of service requested, however without making any guarantees whatsoever.