单播与多播路由选择.ppt

Fall 2006 gcsu@szu.edu.cn Shenzhen University Figure 21.21 路径矢量路由报文 Figure 21.22 BGP报文的类型 21.3 多播路由 IGMP Multicast Trees MBONE Figure 21.23 多播 在多播路由选择中, 路由器通过若干个端口转发数据分组. Note: IGMP 是一个组管理协议. 帮助路由器创建和更新与每个路由器端口相连的可信成员列表. Note: Figure 21.24 IGMP 报文类型 Figure 21.25 IGMP 分组格式 Table 21.4 IGMP 字段 0x17 or 0x16 or 0x11 or Value Leave report Membership report General or special query Type Figure 21.26 IGMP 运作过程 Figure 21.27 成员关系汇报 在IGMP中, 一份成员关系报告要发送两次，并且依次进行. Note: Figure 21.28 离开报告 No Response 通用查询报文并不定义一个特定的组. Note: Figure 21.29 通用查询报文 No Response Example 1 Imagine there are three hosts in a network, as shown in Figure 21.30 (below). A query message was received at time 0; the random delay time (in tenths of seconds) for each group is shown next to the group address. Show the sequence of report messages. Solution The events occur in this sequence: Time 12. The timer for 228.42.0.0 in host A expires and a membership report is sent, which is received by the router and every host including host B which cancels its timer for 228.42.0.0. Time 30. The timer for 225.14.0.0 in host A expires and a membership report is sent, which is received by the router and every host including host C which cancels its timer for 225.14.0.0. Time 50. The timer for 251.71.0.0 in host B expires and a membership report is sent, which is received by the router and every host. Time 70. The timer for 230.43.0.0 in host C expires and a membership report is sent, which is received by the router and every host including host A which cancels its timer for 230.43.0.0. * * Chapter 21 单播与多播路由选择: 路由协议 21.1 单播路由选择 度量 内部与外部路由选择 Figure 21.1 单播路由 在单播路由选择中, 路由器仅通过某个端口转发数据包. Note: 21.2 单播路由协议 RIP OSPF BGP Figure 21.2 常见的路由协议 Figure 21.3 自治系统 Table 21.1 距离矢量路由表 6 4 5 7 Hop Count 131.4.7.19 115.0.0.0 200.5.1.6 189.45.0.0 176.3.6.17 197.5.13.0 172.6.23.4 163.5.0.0 Other information Next Router Destination Receive: a resp