公开(公告)号：WO1996013922A2

公开(公告)日：1996-05-09

申请号：PCT/US1995013838

申请日：1995-10-25

Applicant: CISCO SYSTEMS, INC.

Inventor： CISCO SYSTEMS, INC. ,  LENNEY, Mark, A. ,  CHIN, Hon, Wah

IPC: H04L12/44

CPC classification number: H04L49/351 ,  H04L49/205 ,  H04L49/254 ,  H04L49/45

Abstract: A switching fabric circuit that provides on-the-fly switching of packets, an expandable number of ports, and the interconnection of heterogeneous LAN segments. The switching fabric circuit includes a switching link that comprises a switching bus and a plurality of packet processors, wherein each packet processor is coupled between the switching bus and a LAN segment. The switching bus is a time division multiple access (TDMA) bus, and arbitration for switching bus access is distinct from arbitration for access to the ports of the switching fabric circuit. Switching bus arbitration is done according to one of two priority levels, wherein high priority requests are guaranteed access to the switching bus during a synchronization period in which the high priority requests are made. This provides for guaranteed throughput and on-the-fly switching of packets. Port arbitration may be either uniport port arbitration or multiport port arbitration. Port arbitration is characterized by the transmission of a POE mask by a source port to a destination port and by the subsequent transmission of a DPA signal by the destination port to the source port.

Abstract translation: 提供数据包的实时切换，可扩展数量的端口以及异构LAN段的互连的交换结构电路。 交换结构电路包括交换链路，其包括交换总线和多个分组处理器，其中每个分组处理器耦合在交换总线和LAN分段之间。 交换总线是时分多址（TDMA）总线，用于切换总线访问的仲裁与接入交换结构电路的端口的仲裁不同。 根据两个优先级中的一个完成切换总线仲裁，其中高优先级请求在其中进行高优先级请求的同步时段期间被保证访问交换总线。 这提供了数据包的保证吞吐量和即时切换。 端口仲裁可以是单向端口仲裁或多端口仲裁。 端口仲裁的特征在于将源端口的POE掩码传输到目的端口，并且由目的端口向源端口发送DPA信号。