| 摘要 |
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 and handling unicast as well as multicast traffic. 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 data 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 memory shared switch core only if the switch core can send 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.
|
