Module Matching Schemes for Input-Queued Clos-Network Packet Switches

Abstract

Abstract-Current schemes for configuration of input-queued three-stage Clos-network (IQC) switches involve port matching and path routing assignment, in that order. The implementation of a scheduler capable of matching thousands of ports in largesize switches is complex. To decrease the scheduler complexity for such switches (e.g., 1024 ports or more), we propose a configuration scheme for IQC switches that hierarchizes the matching process. In a practical scenario our scheme performs routing first and port matching thereafter. This approach reduces the scheduler size and the configuration complexity of IQC switches. We show that the switching performance of the proposed approach using weight-based and weightless selection schemes is high under uniform and nonuniform traffic.Index Terms-Clos-network switch, Space-Space-Space switch, matching, input queued, scheduler design.

Packet dispatching using module matching in the modified MSM Clos-network switch

“…Module-level matching algorithms for MSM Clos-network switches were proposed and evaluated in [11][12][13]. The algorithms proposed in [11] and [12] employ two phases: input and output module matching, and then port matching.…”

“…The algorithms proposed in [11] and [12] employ two phases: input and output module matching, and then port matching. The request-grant-accept scheme with many iterations is used to select cells to be transmitted to output modules.…”

Minimizing scheduling complexity with a Clos-network space-space-memory (SSM) packet switch

“…WMF-NP uses the module-matching first approach [6], using weights assigned by the occupancy of the ports corresponding to an input module and destined to an output module. To determine the matching weight of an IM (i)−OM (j) pair, a VOQ module counter V OM C(i, j) is used to count the number of cells at the input ports of IM (i) and destined to…”

“…Configuration schemes may reduce the scheduler size and configuration complexity by grouping ports of a module and by performing module matching [5], [6]. These schemes perform module matching first and port matching thereafter.…”

“…First, we introduce the weighted module-first and none-port matching (WMF-NP) scheme to show that the SSM switch achieves the higher performance than a S 3 switch using a similar scheme, however, with port matching [6]. Then, we introduce the weighted central-module link matching (WCMM) scheme to enhance the performance of the SSM switch by allowing matchings between an IM to multiple OMs and by removing the need of multiple matching iterations.…”