Multicast – Static Mroute SSM
上一篇总结中描述了Static Mroute的应用方法《Multicast – Static Mroute》,它是ASM的模型,也就是组向RP注册生成 (*, G),源向RP注册,生成 (S, G),然后建立SPT进行组播转发。这种效率往往不高,步骤繁多,为了追求更优化的组播解决方案,SSM模型被开发出来并与IGMPv3配合使用。在源特定组播SSM中,他不需要RP,从而也不需要与RP相关的,如MSDP协议,这样大大降低组网的复杂性及维护难度,提高了组播转发效率。这里仍然用同样的topology,把新加的源和组通过SSM来部署,从而配合Static Mroute:
关于IGMPv2的行为和ASM模型的具体实施,可以看我之前的总结《CCIE SP—组播 PIM SM For Join and Reg》。另外如果关注详细的IGMP的信息,可以看我另一篇总结:《Multicast – IGMPv1/2/3》。IGMPv3的主机可以直接支持SSM,而对于仅支持IGMPv2和IGMPv1的主机,需要用SSM Mapping的方式使其支持SSM。
1. 在R4上使用IGMPv3和SSM,然后观察R4和R2的组播表
可以看到R4已经没有(*, G),在R2中有(S, G),因为R2仍然是ASM模型,所以会自动产生(*, G),但事实上没人给它发送(*, G)的注册,所以在OIL中,是null,对于(S, G)表项,也可以看到这时OIL只有一个指向R1,问题解决了
R4#config ter Enter configuration commands, one per line. End with CNTL/Z. R4(config)#ip pim ssm range 1 R4(config)#access-list 1 permit 239.0.200.1 R4(config)# R4(config)#int lo2 R4(config-if)#no ip igmp join-group 239.0.200.1 R4(config-if)#ip igmp join-group 239.0.200.1 source 23.23.23.23 R4(config-if)#end R4# R4#sh ip mroute IP Multicast Routing Table Flags: D - Dense, S - Sparse, B - Bidir Group, s - SSM Group, C - Connected, L - Local, P - Pruned, R - RP-bit set, F - Register flag, T - SPT-bit set, J - Join SPT, M - MSDP created entry, X - Proxy Join Timer Running, A - Candidate for MSDP Advertisement, U - URD, I - Received Source Specific Host Report, Z - Multicast Tunnel, z - MDT-data group sender, Y - Joined MDT-data group, y - Sending to MDT-data group, V - RD & Vector, v - Vector Outgoing interface flags: H - Hardware switched, A - Assert winner Timers: Uptime/Expires Interface state: Interface, Next-Hop or VCD, State/Mode (*, 239.0.100.1), 04:54:26/00:02:18, RP 3.3.3.3, flags: SJCL Incoming interface: FastEthernet1/1, RPF nbr 45.1.1.5 Outgoing interface list: Loopback1, Forward/Sparse, 04:54:26/00:02:18 (23.23.23.23, 239.0.200.1), 00:06:44/stopped, flags: sLTI Incoming interface: FastEthernet1/0, RPF nbr 14.1.1.1, Mroute Outgoing interface list: Loopback2, Forward/Sparse, 00:06:45/00:02:15 (*, 224.0.1.40), 04:54:26/00:02:35, RP 3.3.3.3, flags: SJCL Incoming interface: FastEthernet1/1, RPF nbr 45.1.1.5 Outgoing interface list: FastEthernet1/0, Forward/Sparse, 04:54:26/00:02:25 R2#sh ip mroute IP Multicast Routing Table Outgoing interface flags: H - Hardware switched, A - Assert winner Timers: Uptime/Expires Interface state: Interface, Next-Hop or VCD, State/Mode (*, 239.0.100.1), 00:05:56/00:03:25, RP 3.3.3.3, flags: S Incoming interface: FastEthernet1/0, RPF nbr 23.1.1.3 Outgoing interface list: FastEthernet1/1, Forward/Sparse, 00:05:56/00:03:25 (*, 239.0.200.1), 00:06:25/stopped, RP 3.3.3.3, flags: SP Incoming interface: FastEthernet1/0, RPF nbr 23.1.1.3 Outgoing interface list: Null (23.23.23.23, 239.0.200.1), 00:01:30/00:03:26, flags: T Incoming interface: FastEthernet1/0, RPF nbr 23.1.1.3 Outgoing interface list: FastEthernet0/0, Forward/Sparse, 00:01:30/00:02:59 (*, 224.0.1.40), 00:06:35/00:02:45, RP 3.3.3.3, flags: SJCL Incoming interface: FastEthernet1/0, RPF nbr 23.1.1.3 Outgoing interface list: FastEthernet1/1, Forward/Sparse, 00:05:44/00:02:44 FastEthernet0/0, Forward/Sparse, 00:06:35/00:02:45
2. 在R4上使用IGMPv2和SSM Mapping,然后观察R4和R2的组播表
拿模拟器和ASR1006分别做了测试,发现怎么配置都不行,后来发现不行是正常的。。。SSM-Mapping不支持”igmp-join”,可以用”ip igmp static-group 239.0.200.1 source ssm-map” 来替代”igmp-join”,但是这个命令只支持外部的host,不支持local的。
CSCsr11612, IGMPv2: ip igmp join-group ignored for ssm group when ssm-map configured
ip igmp ssm-map static 1 23.23.23.23 ! interface Loopback2 ip address 24.24.24.24 255.255.255.255 ip pim sparse-mode ip igmp join-group 239.0.200.1 ! access-list 1 permit 239.0.200.1 R4#sh ip mroute IP Multicast Routing Table Outgoing interface flags: H - Hardware switched, A - Assert winner Timers: Uptime/Expires Interface state: Interface, Next-Hop or VCD, State/Mode (*, 239.0.100.1), 00:16:03/00:02:34, RP 3.3.3.3, flags: SJCL Incoming interface: FastEthernet1/1, RPF nbr 45.1.1.5 Outgoing interface list: Loopback1, Forward/Sparse, 00:16:03/00:02:34 (*, 239.0.200.1), 00:16:03/00:02:45, RP 3.3.3.3, flags: SJCL Incoming interface: FastEthernet1/1, RPF nbr 45.1.1.5 Outgoing interface list: Loopback2, Forward/Sparse, 00:16:03/00:02:45 (*, 224.0.1.40), 00:16:03/00:02:50, RP 3.3.3.3, flags: SJCL Incoming interface: FastEthernet1/1, RPF nbr 45.1.1.5 Outgoing interface list: FastEthernet1/0, Forward/Sparse, 00:16:03/00:02:50 R4#show ip igmp groups 239.0.200.1 de Flags: L - Local, U - User, SG - Static Group, VG - Virtual Group, SS - Static Source, VS - Virtual Source, Ac - Group accounted towards access control limit Interface: Loopback2 Group: 239.0.200.1 Flags: L U Uptime: 00:23:45 Group mode: EXCLUDE (Expires: 00:02:26) Last reporter: 24.24.24.24 Source list is empty