Method and apparatus for providing work-conserving properties in a non-blocking switch with limited speedup independent of switch size
US6563837B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 10, 1998 |
| Grant date | May 13, 2003 |
| Priority date | — |
| Expiry date | Feb 10, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L2012/5681
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A switching method and apparatus operates as a work conserving network device. An arbiter using an arbitration algorithm controls a switch fabric interconnecting input ports and output ports. To switch cells, a virtual output queue of an input port is selected that corresponds to an output port with a lowest occupancy rating and a request is sent to this output port. In a greedy version of the algorithm, input ports may send requests to the lowest occupied output port for which they have a cell. In a non-greedy version, requests may only be sent if that input port has a cell for the lowest occupied output port in the entire network device. An output port that receives one or more requests from input ports uses an input port selection algorithm to select an input port from which to receive a packet. After as many input and output ports are matched as is possible in a phase, the packets for those matched ports are transferred across the switch. The switch fabric operates with a speedup of only twice that of the input port data rates and is still work conserving.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.