Programmably sliceable switch-fabric unit and methods of use
A programmably sliceable switch-fabric unit (PSSU) and methods of use are disclosed. An N×N′ switch matrix is programmably made to operate as if it were a plurality of S×S′ virtual switch slices, where S<N and S′<N′. Ingressing requests each specify an egress path (unicast mode) or plural egress paths (multicast mode) in terms of one or more relative egress port numbers. A request translator converts relative egress port numbers into absolute egress port numbers by determining what virtual slice each request belongs to. The translated egress requests are handed off to an arbitration and/or scheduling mechanism for further processing. If the translated request is granted, the corresponding payload egresses through the actual egress port(s) which the translated request asked for. An inventory of PSSU's may be distributed in accordance with the disclosure to segmented markets such that each PSSU can service the specific needs of a market, be it providing a plurality of 4×4 switch slices, 8×8 switch slices, 16×16 switch slices, or otherwise. In one embodiment, virtual slices are distributed throughout a physical switch-matrix so as to minimize pinout crossover for external line card units.
1. A method for configuring a Programmably-Sliceable Switch-fabric Unit (PSSU) having a capability of functioning as an N.times.N′ crossbar, where said PSSU also has a capability of being programmably sliced to instead function as a plurality of S.times.S′ virtual switch slices, where S<N and S′<N′, where the PSSU includes absolute Ingress ports (aI's) and absolute Egress ports (aE's) that are alternatively identifiable as Relative ingress ports (Ri's) and Relative egress ports (Re's) of respective ones of said virtual switch slices; where the aI's can receive routing requests and payloads that are to be routed, and where the aE's can output routed payloads to corresponding destinations; and where said configuring method comprises: (a) executing a program to thereby transform the state of the PSSU to be sliced such that its plural virtual slices are intermingled to provide effective uncrossings of ingress and/or egress signal lines of the PSSU.
2. The method of claim 1 where N equals N′ and S equals S′.
3. The method of claim 1 where N equals 16.
4. The method of claim 1 where N equals 32.
5. The method of claim 1 where N equals 64.
6. The method of claim 1 where N is greater than 64.
7. The method of claim 1 where S is one half of N or less.
8. The method of claim 1 where S is one quarter of N or less.
9. The method of claim 1 wherein said executing the program includes: (a.1) specifying a Scalable Aperture Partitioning mode (SAP mode).
10. The method of claim 9 wherein said executing the program includes: (a.2) in accordance with the SAP mode, specifying a corresponding translation from use of relative (logical) egress identifications to use of absolute (physical) egress identifications.
11. The method of claim 9 wherein said executing the program includes: (a.2) in accordance with the SAP mode, specifying a corresponding request translation to take place within the PSSU.
12. The method of claim 9 wherein said executing the program includes: (a.2) in accordance with the SAP mode, specifying a corresponding multicast translation process to take place within the PSSU.