Figure 15.8 A system of connected LANs and its graph representation LAN 1 LAN2 LAN 3 啤 LAN4 a.Actual system B 1 0 LAN1 ←—0 41 0 B3 1→ LAN2 LAN3 ←—1 ←一0 1 0 LAN4 B5 4一0 —1 b.Graph representation with cost assigned to each arc 15.16
15.16 Figure 15.8 A system of connected LANs and its graph representation
Figure 15.9 Finding the shortest paths and the spanning tree in a system of bridges 1 1 B1 LAN 1 B2 LAN2 LAN3 生成树 B4 B5 11 522 a.Shortest paths Root of spanning tree B1 LAN1 B2 LAN 2 ®国 LAN3 B4- LAN4 B5 b.Spanning tree 15.17
15.17 Figure 15.9 Finding the shortest paths and the spanning tree in a system of bridges 生成树
Figure 15.10 Forwarding and blocking ports after using spanning tree algorithm 生成树 LAN 1 1 Root bridge 2 Blocking LAN2 3 LAN 3 Blocking LAN4 Ports 2 and 3 of bridge B3 are blocking ports(no frame is sent out of these ports) Port 1 of bridge B5 is also a blocking port(no frame is sent out of this port). 15.18
15.18 Figure 15.10 Forwarding and blocking ports after using spanning tree algorithm 生成树
源路由网桥 ■是防止有环的另外一种方法 ■透明网桥的指责（过滤帧、转发和阻塞）有源 站点来执行，目中程度上有目的站点来执 行。 ■有源方指定帧必须经过的网桥。 ■被用于令牌环网。 15.19
源路由网桥 是防止有环的另外一种方法 透明网桥的指责(过滤帧、转发和阻塞)有源 站点来执行，目中程度上有目的站点来执 行。 有源方指定帧必须经过的网桥。 被用于令牌环网。 15.19
网桥与广播风暴 结点101 结点205 504 Data 504 Data 局域网1 局域网3 N.1 N.3 网桥 N.4 局域网2 局域网4 504Data 504 Data 结点803 结点504
网桥与广播风暴 局域网1 结点101 结点205 结点803 结点504 N.1 N.2 N.3 N.4 局域网2 局域网3 局域网4 网桥 504 Data 504 Data 504 Data 504 Data