ITAA工程师 2008-1-23 11:20
原创 IP 直播
[size=6][font=Times New Roman]IP[/font][font=黑体][size=24pt]直播[/size][/font][/size][size=24pt][/size]
R1(S1/0)---------(S2/0)R2(E0/0)----------(E0/0)R3
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Figure 8 IP[font=黑体]直播[/font]
[font=宋体]
[/font][font=宋体]默认情况下，广播数据报文是没法穿过路由器传播的，有这么一些应用，向处在一个广播域的全部主机发送广播，但是发送者并不处在这 个广播域内，这个时候，希望有一种能够使用单播数据报文穿过路由网络，但到达目的网络时，以广播方式发放（这种应用一般可视为有 去无回，大都是无连接的UDP应用）。IP直播在IOS里面广泛被支持。[/font]
[font=宋体]
[/font][font=宋体]以下配置，R3就是处在接收广播域内的一个成员，而R1是发送者，而R2正是一个将单播转换为广播的路由器。使用OSPF保持路由连通，环回口在这个实验并无实质应用，OSPF的数据报为组播224.0.0.5，在debug调试时，最好过滤掉输出这类信息。[/font]
R1
[size=9pt]![/size]
[size=9pt]hostname
R1[/size]
[size=9pt]![/size]
[size=9pt]interface
Loopback0[/size]
[size=9pt]ip
address 1.1.1.1 255.255.255.0[/size]
[size=9pt]
ip ospf network point-to-point[/size]
[size=9pt]![/size]
[size=9pt]interface
Serial1/0[/size]
[size=9pt]
ip address 12.1.1.1 255.255.255.0[/size]
[size=9pt]
clockrate 64000[/size]
[size=9pt]![/size]
[size=9pt]router
ospf 10[/size]
[size=9pt]
router-id 1.1.1.1[/size]
[size=9pt]network
0.0.0.0 255.255.255.255 area 0[/size]
[size=9pt]![/size]
R2
[size=9pt]![/size]
[size=9pt]hostname
R2[/size]
[size=9pt]![/size]
[size=9pt]interface
Loopback0[/size]
[size=9pt]
ip address 2.2.2.2 255.255.255.0[/size]
[size=9pt]
ip ospf network point-to-point[/size]
[size=9pt]![/size]
[size=9pt]interface
Ethernet0/0[/size]
[size=9pt]
ip address 10.1.1.2 255.255.255.0[/size]
[size=9pt]![/size]
[size=9pt]interface
Serial2/0[/size]
[size=9pt]
ip address 12.1.1.2 255.255.255.0[/size]
[size=9pt]![/size]
[size=9pt]router
ospf 10[/size]
[size=9pt]
router-id 2.2.2.2[/size]
[size=9pt]
network 0.0.0.0 255.255.255.255 area 0[/size]
[size=9pt]![/size]
R3
[size=9pt]![/size]
[size=9pt]hostname
R3[/size]
[size=9pt]![/size]
[size=9pt]interface
Loopback0[/size]
[size=9pt]
ip address 3.3.3.3 255.255.255.0[/size]
[size=9pt]
ip ospf network point-to-point[/size]
[size=9pt]![/size]
[size=9pt]interface
Ethernet0/0[/size]
[size=9pt]
ip address 10.1.1.3 255.255.255.0[/size]
[size=9pt]![/size]
[size=9pt]router
ospf 10[/size]
[size=9pt]
router-id 3.3.3.3[/size]
[size=9pt]
network 0.0.0.0 255.255.255.255 area 0[/size]
[size=9pt]![/size]
监视和测试配置
[font=宋体]路由器可以转发主机位全为[/font]1[font=宋体]的目的地址，对于中间路由器，转发数据报文，只检查网络位，因此这些数据报文在到达最后[/font]1[font=宋体]跳时，转发和普通数据包无异：[/font]
1)[font=宋体]打开[/font]R2[font=宋体]、[/font]R3[font=宋体]的调试开关[/font]
[size=9pt]R2(config)#access-list 101
permit icmp any any[/size]
[size=9pt]R2#debug ip packet 101[/size]
[size=9pt]IP packet debugging is on for
access list 101[/size]
[font=宋体]以上定义访问列表的意义是调试只输出[/font]ICMP[font=宋体]相关数据包，这样可以避免[/font]OSPF[font=宋体]的[/font]hello[font=宋体]干扰。[/font]
2[font=宋体]）打开[/font]R2[font=宋体]的[/font]Ethernet0/0[font=宋体]接口转发直播[/font]
[size=9pt]R2(config)#int e0/0[/size]
[size=9pt]R2(config-if)#ip
directed-broadcast[/size]
[b]3[/b][b][font=宋体]）在[/font][/b][b]R1
ping 10.1.1.0/24[/b][b][font=宋体]目标网段，发起一个主机位全为[/font][/b][b]1[/b][b][font=宋体]的地址。[/font][/b][b][/b]
[size=9pt]R1#ping 10.1.1.255[/size]
[size=9pt] [/size]
[size=9pt]Type escape sequence to
abort.[/size]
[size=9pt]Sending 5, 100-byte ICMP
Echos to 10.1.1.255, timeout is 2 seconds:[/size]
[size=9pt]!!!!![/size]
[size=9pt]Success rate is 100 percent
(5/5), round-trip min/avg/max = 8/20/32 ms[/size]
[size=9pt] [/size]
[font=宋体]4)[/font][font=宋体]查看R2的调试输出，关键部分为粗体显示：[/font]
[font=宋体] [/font]
[font=宋体][size=9pt]*Jul 25 20:57:03.879: IP: s=[b]12.1.1.1[/b] (Serial2/0), d=[b]10.1.1.255[/b] (Ethernet0/0), g=[b]255.255.255.255[/b], len 100, [b]forward directed broadcast[/b][/size][/font]
[font=宋体][size=9pt]*Jul 25 20:57:03.879: IP: s=12.1.1.1
(Serial2/0), d=10.1.1.255 (Ethernet0/0), len 100, rcvd 5[/size][/font]
[font=宋体][size=9pt]*Jul 25 20:57:03.879: IP: s=12.1.1.2
(local), d=12.1.1.1 (Serial2/0), len 100, sending[/size][/font]
[font=宋体][size=9pt]*Jul 25 20:57:03.899: IP: s=12.1.1.1
(Serial2/0), d=10.1.1.255 (Ethernet0/0), g=255.255.255.255, len 100, forward
directed broadcast[/size][/font]
[font=宋体][size=9pt]（以下重复，输出省略）[/size][/font]
[font=宋体][size=9pt] [/size][/font]
[font=宋体]可见R2已经将数据报文转为广播方式，向10.1.1.0/24所在接口转发。[/font]
[font=宋体][size=9pt] [/size][/font]
[font=宋体]5)[/font][font=宋体]查看R3调试输出，关键部分为粗体显示：[/font]
[font=宋体][size=9pt]*Jul 25 20:59:06.079: IP: s=12.1.1.1
(Ethernet0/0), [b]d=255.255.255.255[/b],
len 100, rcvd 2[/size][/font]
[font=宋体][size=9pt]*Jul 25 20:59:06.079: IP: s=10.1.1.3
(local), d=12.1.1.1 (Ethernet0/0), len 100, sending[/size][/font]
[font=宋体][size=9pt]*Jul 25 20:59:06.099: IP: s=12.1.1.1
(Ethernet0/0), d=255.255.255.255, len 100, rcvd 2[/size][/font]
[font=宋体][size=9pt]*Jul 25 20:59:06.099: IP: s=10.1.1.3
(local), d=12.1.1.1 (Ethernet0/0), len 100, sending[/size][/font]
[font=宋体][size=9pt]*Jul 25 20:59:06.119: IP: s=12.1.1.1
(Ethernet0/0), d=255.255.255.255, len 100, rcvd 2[/size][/font]
[font=宋体][size=9pt]*Jul 25 20:59:06.119: IP: s=10.1.1.3
(local), d=12.1.1.1 (Ethernet0/0), len 100, sending[/size][/font]
[font=宋体][size=9pt]*Jul 25 20:59:06.139: IP: s=12.1.1.1
(Ethernet0/0), d=255.255.255.255, len 100, rcvd 2[/size][/font]
[font=宋体][size=9pt]*Jul 25 20:59:06.139: IP: s=10.1.1.3
(local), d=12.1.1.1 (Ethernet0/0), len 100, sending[/size][/font]
[font=宋体][size=9pt]*Jul 25 20:59:06.167: IP: s=12.1.1.1
(Ethernet0/0), d=255.255.255.255, len 100, rcvd 2[/size][/font]
[font=宋体][size=9pt]*Jul 25 20:59:06.167: IP: s=10.1.1.3
(local), d=12.1.1.1 (Ethernet0/0), len 100, sending[/size][/font]
[size=9pt] [/size]
[font=宋体]
R3[/font][font=宋体]收到广播数据报文，并以单播方式应答ping。[/font]
[font=宋体] [/font]
[font=宋体]6)[/font][font=宋体]关闭R2的Ethernet0/0接口直播[/font]
[font=宋体] [/font]
[size=9pt]R2(config)#interface ethernet
0/0[/size]
[size=9pt]R2(config-if)#no ip
directed-broadcast[/size]
[font=宋体] [/font]
[font=宋体]7)R1[/font][font=宋体]再次发起ping 目标网段10.1.1.0/24,主机位为全为1。[/font]
[font=宋体]R1#ping
10.1.1.255[/font]
[font=宋体] [/font]
[font=宋体]Type
escape sequence to abort.[/font]
[font=宋体]Sending
5, 100-byte ICMP Echos to 10.1.1.255, timeout is 2 seconds:[/font]
[font=宋体]!!!!![/font]
[font=宋体]Success
rate is 100 percent (5/5), round-trip min/avg/max = 20/20/20 ms[/font]
[font=宋体] [/font]
[font=宋体]8)[/font][font=宋体]查看R2调试输出：[/font]
[font=宋体] [/font]
[font=宋体][size=9pt]*Jul 25 21:05:22.071: IP: s=12.1.1.1
(Serial2/0), d=10.1.1.255 (Ethernet0/0), len 100, rcvd 5[/size][/font]
[font=宋体][size=9pt]*Jul 25 21:05:22.071: IP: s=12.1.1.2
(local), d=12.1.1.1 (Serial2/0), len 100, sending[/size][/font]
[font=宋体][size=9pt]*Jul 25 21:05:22.099: IP: s=12.1.1.1
(Serial2/0), d=10.1.1.255 (Ethernet0/0), len 100, rcvd 5[/size][/font]
[font=宋体][size=9pt]*Jul 25 21:05:22.099: IP: s=12.1.1.2
(local), d=12.1.1.1 (Serial2/0), len 100, sending[/size][/font]
[font=宋体][size=9pt]*Jul 25 21:05:22.131: IP: s=12.1.1.1
(Serial2/0), d=10.1.1.255 (Ethernet0/0), len 100, rcvd 5[/size][/font]
[font=宋体][size=9pt]*Jul 25 21:05:22.131: IP: s=12.1.1.2
(local), d=12.1.1.1 (Serial2/0), len 100, sending[/size][/font]
[font=宋体][size=9pt]*Jul 25 21:05:22.159: IP: s=12.1.1.1
(Serial2/0), d=10.1.1.255 (Ethernet0/0), len 100, rcvd 5[/size][/font]
[font=宋体][size=9pt]*Jul 25 21:05:22.159: IP: s=12.1.1.2
(local), d=12.1.1.1 (Serial2/0), len 100, sending[/size][/font]
[font=宋体][size=9pt]*Jul 25 21:05:22.191: IP: s=12.1.1.1
(Serial2/0), d=10.1.1.255 (Ethernet0/0), len 100, rcvd 5[/size][/font]
[font=宋体][size=9pt]*Jul 25 21:05:22.191: IP: s=12.1.1.2 (local),
d=12.1.1.1 (Serial2/0), len 100, sending[/size][/font]
[font=宋体][size=9pt] [/size][/font]
[font=宋体]只有单播的应答，R2使用接收直播的接口应答（即S2/0），R2没有再将直播数据报转换成广播方式向Ethernet0/0发送。[/font]
[font=宋体] [/font]
[font=宋体]
9)[/font][font=宋体]查看R3调试输出：[/font]
[font=宋体] [/font]
[font=宋体]
R3[/font][font=宋体]没有调试输出，原因如上，R2关闭直播后，在对应接口，不再转换直播地址为广播发送。[/font]
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