文档介绍：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 )
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)
(Password Recovery) 5. VLAN操作(VLAN Operations)
(Configuring and Verifying Static VLANs)
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)
初始MAC地址表是空的
Initial MAC address table is empty
MAC address table
E0
E1
E2
E3
A
B
C
D
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
E0:
E0
E1
E2
E3
D
C
B
A
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
E0:
E3:
E0
E1
E2
E3
D
C
A
B
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:
E2:
E1:
E3:
E0
E1
E2
E3
X
X
D
C
A
B
MAC address table
两种交换方法(Two Switching Methods)
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