Hi! We implemented IPv4 Multicast Service Reflection (for IPTV) several years ago and it worked just fine until several weeks ago our reflectors started corrupting a picture.
To be specific: we have a vlan 412 with upstream IPv4 multicast source for about 100 multicast groups/IPTV channels from same provider that supports both of IGMP join and PIM. This source comes via single 1Gbps optical L2 port to our 7600 RSP720-3C-GE core router, the port load is 357Mbps at max. We also use several Cisco 7201 routers connected to the same vlan as PIM routers and Multicast Service Reflectors. Each of 7201 routers joins nonoverlapping set of groups on its Gi0/0, performs multicast-to-multicast reflection and sends result over its Gi0/1.14 back to the same 7600 core router that is a PIM router, too. CPU load of 7201 routers is steady and less than 60%. Incoming streams contain nice and clean pictures and until recently reflected streams were fine, too. Suddenly reflected streams went bad with visual artefacts due to severe skipped frames (over 2.2%) and discontinues in transport streams and I started looking closely. No errors at physical layer, no bad CRC, no packet drops, no full buffers. However, physical ports load graphs show that 7600 started flooding some part of reflected multicasts back to the vlan 412 and now 7201 routers have to receive and drop extra multicast traffic received over its Gi0/1 ports, upto 100Mbps. Gi0/1 ports of 7201 routers are supposed to have nearly zero input load but that's not true anymore. I suspect this may be the source of the problem as I already tried to replace 7201 routers, switch their connections to the 7600 from copper ports to optical ones and vise versa, no changes at all. Also, I rebooted 7600 core router having uptime over 6 years, no changes too. I also mirrored traffic sent inadequately from 7600 to Gi0/1 of 7201 and my packet analyzer shows reflected streams there. I cannot understand why. 7600 has IGMP snooping and PIM snooping enabled and should not behave so, to my understanding... Some part of 7600 router configuration running image c7600rsp72043-adventerprisek9-mz.152-4.S6: ! bidir unused really, PIM-SM in use only ip pim bidir-enable ip pim rp-address A.A.A.A list1 override ip pim rp-address B.B.B.B list2 override ... ip pim rp-address F.F.F.F list6 override ip pim autorp listener ip pim send-rp-announce Loopback0 scope 4 group-list Bars ip pim send-rp-discovery Loopback0 scope 4 ip pim rp-announce-filter rp-list iptv-rp group-list all-multicast ip pim snooping no ip pim snooping dr-flood ! interface Vlan412 description "IPTV source" ip address 172.31.0.2 255.255.255.0 ip pim sparse-mode ip pim snooping ip igmp query-interval 125 ! interface Vlan14 description "IPTV reflected" ip address X.X.X.X 255.255.255.240 ! Real PIM DR of upstream has priority 100 and 7201 routers have defaults of 1 ip pim dr-priority 10 ip pim sparse-mode ip pim snooping ip igmp query-interval 125 ip igmp snooping querier end Some part of 7201 routers configuration: buffers small permanent 60 buffers small max-free 180 buffers small min-free 25 buffers middle permanent 30 buffers middle max-free 180 buffers middle min-free 15 buffers big permanent 500 buffers big max-free 1500 buffers big min-free 50 buffers verybig permanent 500 buffers verybig max-free 50 buffers verybig min-free 50 ! ip pim rp-address A.A.A.A list1 override ip pim rp-address B.B.B.B list2 override ... ip pim rp-address F.F.F.F list6 override ip pim send-rp-announce Loopback0 scope 4 group-list reflected ip pim register-rate-limit 8000 ! interface GigabitEthernet0/0 description "Source" mtu 1636 ip address 172.31.0.11 255.255.255.0 ip pim sparse-mode ip igmp query-interval 125 load-interval 30 duplex auto speed 1000 media-type rj45 negotiation auto hold-queue 4096 in ! interface GigabitEthernet0/1 mtu 1636 no ip address ! unused, no Netflow generation really ip flow ingress load-interval 30 duplex auto speed 1000 media-type rj45 negotiation auto hold-queue 4096 in hold-queue 4096 out ! interface GigabitEthernet0/1.14 description "Reflected" encapsulation dot1Q 14 ip address X.X.X.A 255.255.255.240 ip pim sparse-mode ! interface Vif1 ip address 172.18.0.1 255.255.255.252 ! An example for one of multiple reflected groups ip service reflect GigabitEthernet0/0 destination 239.13.0.1 to 239.45.1.128 mask-len 32 source 172.18.0.2 ip pim sparse-mode ip igmp static-group 239.13.0.1 ! I'm ready to supply more information, if needed. _______________________________________________ cisco-nsp mailing list cisco-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
