System and method for collapsing VOQ's of a packet switch fabric
US7706394B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 20, 2004 |
| Grant date | Apr 27, 2010 |
| Priority date | — |
| Expiry date | Oct 16, 2028 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L49/3045
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A system and a method to avoid packet traffic congestion in a shared-memory switch core, while dramatically reducing the amount of shared memory in the switch core and the associated egress buffers, is disclosed. According to the invention, the virtual output queuing (VOQ) of all ingress adapters of a packet switch fabric are collapsed into its central switch core to allow an efficient flow control. The transmission of packets from an ingress buffer to the switch core is subject to a mechanism of request/acknowledgment. Therefore, a packet is transmitted from a virtual output queue to the shared-memory switch core only if the switch core can actually forward it to the corresponding egress buffer. A token based mechanism allows the switch core to determine the egress buffer's level of occupation. Therefore, since the switch core knows the states of the input and output adapters, it is able to optimize packet switching and to avoid packet congestion. Furthermore, since a packet is admitted in the switch core only if it can be transmitted to the corresponding egress buffer, the shared memory is reduced.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.