公开(公告)号：US5740175A

公开(公告)日：1998-04-14

申请号：US538321

申请日：1995-10-03

申请人： Laurence N. Wakeman ,  Roy T. Myers, Jr.

发明人： Laurence N. Wakeman ,  Roy T. Myers, Jr.

IPC分类号： H04L12/56 ,  H04Q11/04

CPC分类号： H04L49/351 ,  H04L49/25

摘要： A LAN network switch includes a RAM forwarding database which contains the address-to-port mappings for all the workstations or other devices connected to the switch's plurality of ports and further includes at least one CAM-cache connected to respective one or more of the switch's ports. The CAM-cache, having an access time much faster than that of the forwarding database, stores selected ones of the address-to-port mappings. When it is desired for the switch to forward a packet, the destination address is extracted and the CAM-cache is accessed and searched. If the correct mapping is contained in the CAM-cache, the packet is immediately forwarded to the destination port without accessing the much larger and slower forwarding database. Only if the CAM-cache does not contain the correct mapping is the forwarding database accessed to retrieve the correct mapping. The packet is then forwarded to the destination port, and the CAM-cache is updated with this mapping so that succeeding packets having the same destination address-to-port mapping may be forwarded to the destination port by accessing only the fast CAM-cache and, by eliminating the need to access the much slower forwarding database, increasing the forwarding speed of the switch.

摘要翻译： LAN网络交换机包括RAM转发数据库，​​其包含用于所有工作站或连接到交换机的多个端口的其他设备的地址对端口映射，并且还包括连接到交换机的多个端口中的一个或多个的至少一个CAM缓存 港口。 具有比转发数据库快的访问时间的CAM缓存存储所选择的地址到端口映射。 当需要转发转发数据包时，提取目的地址，并访问和搜索CAM高速缓存。 如果正确的映射包含在CAM缓存中，则数据包将立即转发到目标端口，而无需访问更大和更慢的转发数据库。 只有CAM-cache不包含正确的映射，才能访问转发数据库以检索正确的映射。 然后将数据包转发到目标端口，并且使用该映射更新CAM缓存，使得具有相同目的地地址到端口映射的后续分组可以通过仅访问快速CAM缓存而被转发到目的地端口，并且 ，通过消除访问速度较慢的转发数据库的需要，增加交换机的转发速度。