发明授权
- 专利标题: Forwarding database cache for integrated switch controller
- 专利标题(中): 转发集成交换机控制器的数据库缓存
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申请号: US538321申请日: 1995-10-03
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公开(公告)号: US5740175A公开(公告)日: 1998-04-14
- 发明人: Laurence N. Wakeman , Roy T. Myers, Jr.
- 申请人: Laurence N. Wakeman , Roy T. Myers, Jr.
- 申请人地址: CA Santa Clara
- 专利权人: National Semiconductor Corporation
- 当前专利权人: National Semiconductor Corporation
- 当前专利权人地址: CA Santa Clara
- 主分类号: H04L12/56
- IPC分类号: H04L12/56 ; H04Q11/04
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.
公开/授权文献
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