M1-交换机基本原理.pptVIP

Outline 广播域和冲突域 交换机处理帧的三种模式 交换机的学习逻辑 交换机的转发与过滤逻辑 Ethernet Switches and Bridges MAC Address Table Learning Addresses Learning Addresses (Cont.) Filtering Frames Filtering Frames (Cont.) Broadcast and Multicast Frames REVIEW MAC地址表的创建是依靠帧的源MAC，默认的超时时间是多少秒？ Show mac-address-table可以查看MAC地址表 交换机对广播流量与多播流量如何转发？ ? 2004 Cisco Systems, Inc. All rights reserved. ICND v2.2—1-* * ? 2004 Cisco Systems, Inc. All rights reserved. ? 2004 Cisco Systems, Inc. All rights reserved. ICND v2.2—1-* 交换 1．交换机的基本原理 Address learning Forwarding the filtering decisions Loop avoidance Cut-Through Switch checks destination address and immediately begins forwarding frame Fragment-Free Switch checks the first 64 bytes, then immediately begins forwarding frame Store and Forward Complete frame is received and checked before forwarding Transmitting Frames The initial MAC address table is empty. Station A sends a frame to station C. The switch caches the MAC address of station A to port E0 by learning the source address of data frames. The frame from station A to station C is flooded out to all ports except port E0 (unknown unicasts are flooded). Station D sends a frame to station C. The switch caches the MAC address of station D to port E3 by learning the source address of data frames. The frame from station D to station C is flooded out to all ports except port E3 (unknown unicasts are flooded). Station A sends a frame to station C. The destination is known; the frame is not flooded. Station A sends a frame to station B. The switch has the address for station B in the MAC address table. Station D sends a broadcast or multicast frame. Broadcast and multicast frames are flooded to all ports other than the originating port. Purpose: This slide discuss the initial configurations on the routers and switches. Note: There is no setup mode on the Catalyst 1900 switch. Emphasize: The next few slides discuss the basic function of a bridge/switch: 1. How it learns the location of the hosts by reading