Evaluating several implementations for the AS Minimum Bandwidth Egress Link Scheduler

The relevance of the provision of QoS is taken into account in the definition of the new network technologies like for example Advanced Switching (AS). AS is a new fabric-interconnect technology that further enhances the capabilities of PCI Express, which is the next PCI generation. In this paper we discuss the aspects that must be considered for implementing a specific mechanism for the AS minimum bandwidth egress link scheduler, or just MinBW scheduler. We also propose several implementations for this scheduler, analyze their computational complexity, and compare their performance by simulation. The main differentiating aspect from other interconnection technologies that must be taken into account when implementing the AS MinBW scheduler is that both the link-level flow control and the scheduling are made at a Virtual Channel (VC) level. This means that the scheduler must have the ability to enable or disable the selection of a given VC based on the flow control information.