| 摘要 |
Described herein is a method of cell level scheduling for handling unicast traffic in routing devices, for example, crossbar switches. This is achieved by the provision of support for multimedia and real-time traffic in large bandwidth routing devices known as terabit routers. Each terabit route r has a plurality of ingress line interface cards (210, 212, 214, 216), a plurality of egress line interface cards (220, 222, 224, 226) and a cell based cross-b ar (202). Each ingress card has a plurality of queues, a different queue for ea ch of the egress cards respectively. The cross-bar (202) is controlled by a cro ss- bar controller (204) in association with a bandwidth controller (206). In operation, a target rate matrix is maintained over a set period. At the beginning of each period, a matrix of numbers of cells queued to be transmitted is calculated in accordance with the target rate. For each successive cell slot within the period, a configuration is found which match es the cell number matrix by servicing only queues which have non-zero cell counts. At the end of the period, the cell counts are all zero. |
