交换和VLAN cning and VLAN 厦 Cisco.com 深圳职业技术学院计算机系网络专业
© 2006, Shenzhen Polytechnic, All rights reserved. 1 交换和VLAN Switching and VLAN 深圳职业技术学院计算机系网络专业
教学目标(Objectives) Cisco.com 1.交换机学习主机地址 (Switche Learn Host Address) 2.两种交换方法(Two Switching Methods) 3.配置端口安全(Configuring Port Security) 4.密码破解(Password Recovery) 5.VLAN操作(VLAN Operations) 6.配置和验证静态VLAN (Configuring and Verifying Static VLANs) 2006,By Shenzhen Polytechnic.All rights reserved
© 2006, By Shenzhen Polytechnic. All rights reserved. 2 教学目标（ Objectives ） 1. 交换机学习主机地址 （Switche Learn Host Address） 2. 两种交换方法（Two Switching Methods） 3. 配置端口安全（Configuring Port Security） 4.密码破解（Password Recovery） 5. VLAN操作（VLAN Operations） 6.配置和验证静态VLAN (Configuring and Verifying Static VLANs)
交换机三种功能 (Three Switch Functions 厦 Cisco.com 盟 。地址学习（Address learning) ·决定转发或过滤(Forward/.filter decision) ·避免环路(Loop avoidance) 2006,By Shenzhen Polytechnic.All rights reserved
© 2006, By Shenzhen Polytechnic. All rights reserved. 3 • 地址学习（Address learning） • 决定转发或过滤（Forward/filter decision） • 避免环路（Loop avoidance） 交换机三种功能 （Three Switch Functions ）
交换机学习主机地址 (Switche Learn Host Address) wwccmm Cisco.com MAC address table A B 0260.8c01.1111 E1 0260.8c01.3333 E3 D 0260.8c01.2222 0260.8c01.4444 ·初始MAC地址表是空的 Initial MAC address table is empty 00,By Shenzhen Polytechnic.All rightsreserved
© 2006, By Shenzhen Polytechnic. All rights reserved. 4 交换机学习主机地址 （Switche Learn Host Address） • 初始MAC地址表是空的 • Initial MAC address table is empty MAC address table 0260.8c01.1111 0260.8c01.2222 0260.8c01.3333 0260.8c01.4444 E0 E1 E2 E3 A B C D
交换机学习主机地址 (Switche Learn Host Address) IIIIIIIIIIIW Cisco.com MAC address table E0:0260.8c01.1111 ◆B 0260.8c01.1111 E1 0260.8c01.3333 E2 E3 D 0260.8c01.2222 0260.8c01.4444 ·A向C发送帧(StationA sends a frame to Station C) 交换机将A的MAC地址和其对应的接口E0放入MAC地址表 Switch caches station A MAC address to port E0 by learning the source address of data frames ·该帧向除了E0接口的所有接口泛洪 The frame from station A to station C is flooded out to all ports except port Eo
© 2006, By Shenzhen Polytechnic. All rights reserved. 5 交换机学习主机地址 （Switche Learn Host Address） • A向C发送帧（Station A sends a frame to Station C） • 交换机将A的MAC地址和其对应的接口E0放入MAC地址表 • Switch caches station A MAC address to port E0 by learning the source address of data frames • 该帧向除了E0接口的所有接口泛洪 • The frame from station A to station C is flooded out to all ports except port E0 MAC address table 0260.8c01.1111 0260.8c01.2222 0260.8c01.3333 0260.8c01.4444 E0: 0260.8c01.1111 E0 E1 E2 E3 C D A B
交换机学习主机地址 (Switche Learn Host Address) I Cisco.com MAC addresstable E0:0260.8c01.1111 E3:0260.8c01.4444 A B 0260.8c01.1111 E1 0260.8c01.3333 c E2 E3 0260.8c01.2222 0260.8c01.4444 ·D向c发送帧(Station D sends a frame to station C) ·交换机将D的MAC地址和其对应的接口E3放入MAC地址表 。 Switch caches station D MAC address to port E3 by learning the source Address of data frames 该帧向除了E3接口的所有接口泛洪 The frame from station D to station C is flooded out to all ports except port E3(unknown unicasts are flooded)
© 2006, By Shenzhen Polytechnic. All rights reserved. 6 交换机学习主机地址 （Switche Learn Host Address） • D向C发送帧(Station D sends a frame to station C) • 交换机将D的MAC地址和其对应的接口E3放入MAC地址表 • Switch caches station D MAC address to port E3 by learning the source Address of data frames • 该帧向除了E3接口的所有接口泛洪 • The frame from station D to station C is flooded out to all ports except port E3 (unknown unicasts are flooded) MAC address table 0260.8c01.1111 0260.8c01.2222 0260.8c01.3333 0260.8c01.4444 E0: 0260.8c01.1111 E3: 0260.8c01.4444 E0 E1 C E2 E3 D A B
交换机过滤帧(Switches Filter Frames) IIWWIE Cisco.com MAC address table E0:0260.8c01.1111 E2:0260.8c01.2222 A E1:0260.8c01.3333 B E3:0260.8c01.4444 0260.8c01.1111 0260.8c01.3333 c于 D 0260.8c01.2222 0260.8c01.4444 ·A向C发送帧 Station A sends a frame to station C ·目的地址已知，帧不被泛洪 Destination is known,frame is not flooded ,By Shenzhen Polytechnic
© 2006, By Shenzhen Polytechnic. All rights reserved. 7 交换机过滤帧（ Switches Filter Frames） • A向C发送帧 • Station A sends a frame to station C • 目的地址已知，帧不被泛洪 • Destination is known, frame is not flooded E0: 0260.8c01.1111 E2: 0260.8c01.2222 E1: 0260.8c01.3333 E3: 0260.8c01.4444 0260.8c01.1111 0260.8c01.2222 0260.8c01.3333 0260.8c01.4444 E0 E1 E2 E3 X C X D A B MAC address table
两种交换方法(Two Switching Methods) Cisco.com T
© 2006, By Shenzhen Polytechnic. All rights reserved. 8 两种交换方法（Two Switching Methods）
存储转发特征(Store-.and-forward Feature) d Cisco.com 1.在转发之前整个帧被接收 The entire frame is received before any forwarding takes place. 2由于交换开始之前要接收完整帧，较大的数据 帧延迟较大 Latency is greater with larger frames because the entire frame must be received before the switching process begins. 2006,By Shenzhen Polytechnic.All rights reserved
© 2006, By Shenzhen Polytechnic. All rights reserved. 9 存储转发特征（Store-and-forward Feature） 1. 在转发之前整个帧被接收 The entire frame is received before any forwarding takes place. 2.由于交换开始之前要接收完整帧，较大的数据 帧延迟较大 Latency is greater with larger frames because the entire frame must be received before the switching process begins
直通特征(Cut-through Feature) IWE Cisco.com 1在接收完整帧之前，帧就被转发。 The frame is forwarded through the switch before the entire frame is received. 2.最快的是只要读到目的地址就转发。 At a minimum the frame destination address must be read before the frame can be forwarded. 3.这种模式降低了延迟，但是不进行检错 This mode decreases the latency of the transmission,but also reduces error detection. 2006,By Shenzhen Polytechnic.All rights reserved
© 2006, By Shenzhen Polytechnic. All rights reserved. 10 直通特征（Cut-through Feature） 1.在接收完整帧之前，帧就被转发。 The frame is forwarded through the switch before the entire frame is received. 2.最快的是只要读到目的地址就转发。 At a minimum the frame destination address must be read before the frame can be forwarded. 3.这种模式降低了延迟，但是不进行检错 This mode decreases the latency of the transmission, but also reduces error detection