SRS-Based QoS Scheme
Motivated by the SRS design, its dropping policy, and the use of the FCRB field, the SRSbased
QoS mechanism is introduced. In this mechanism, the QoS requirements of the upper
layer packets are defined based on their traffic class. Packets of the same class and destination
are assembled into the same data segment, which will be labeled with a priority number
accordingly. A data burst may contain data segments of the same or different priorities. Using
an appropriate assembly algorithm, the data segments are assembled into data bursts in
such a way that the lower priority data segments envelop the higher priority data segments
as shown in Figure 6(b). To realize the SRS-based QoS scheme, both the edge nodes and
core nodes must cooperate, using an assembly algorithm in the edge nodes and the SRS
dropping policy in core nodes.
Assembly Algorithm
Although either timer-based or burstlength-based assembly algorithm could be used, it is
preferred to use hybrid assembly algorithms. In the hybrid approach, first a burst length
threshold is used in assembling the data segments; this allows the control of the data segments
size, which must be fixed and restricted to a maximum length.
Pages:
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795