Re: Multicast issue

I think your network is so simple that you don't even need an rp or
mapping agent, the source and destination are connected to the same
router so there is no need for the type of multicast routing that
requires a RP.

I suspect the rpf failures are because it is an ethernet segment and
when one router forwards the packets towards the client the other
router also gets a copy of those packets, then drops them as rpf
failures.

When I have tried to use a switch to simulate an igmp host it required
enabling multicast routing and pim on the interface, as well as the
igmp join-group command, I'm not exactly sure why this is, but without
it the switch would not reply to icmp's. The solution when doing this
is to add a pim neighbor filter on the interface to stop it from
forming an adjacency.

HTH

Jason

On 5 August 2010 23:45, Maarten Vervoorn <mr.vervoorn_at_gmail.com> wrote:
> I don't think thats the issue here. It is a multiple access network all
> switches can reach eachother directly.
> The routers do reply to the traffic altough they configured the same. There
> is some sort of difference in joining a group from a SVI interface and a
> physical router interfice. I'm trying to find out what it is.
> If I enable multicast routing with sparse mode on SW3 it will also reply to
> 226.1.1.1. But I don;t think that should be nessecary. Its is acting like a
> client so I do not want to enable pim on SW3 just link on the oter routers I
> have tested.
>
> Anyone any idea what the issue could be here?
>
> 2010/8/5 Adrian Brayton <abrayton_at_gmail.com>
>
>> Hey Maarten,
>>
>> From the looks of your topology, your going to have multiple paths to the
>> same source... Have you looked into multicast multipath (I think that is for
>> load balancing so it probably doesn't even relate to your issue)? I have
>> never tried it myself so I cant say with any certainty whether that will
>> help or not.
>>
>> This example doesn't relate to your specific situation but it might be a
>> similar idea... When you set up FR Multipoint, you will run into an issue
>> where the physical interface of the "HUB" wont send out multicast traffic to
>> one or more of the spokes. So to resolve this issue you need to create
>> another interface to send out the multicast traffic "insert tunnel here" so
>> now the hub has another interface in which to send out the multicast
>> traffic. You will also need to add a static mroute but hopefully you get the
>> idea!
>>
>> Or maybe just a simple static mroute will fix your RPF issues!
>>
>> HTHs a little but its early and just woke up!
>>
>>
>> On Aug 5, 2010, at 4:13 AM, Maarten Vervoorn wrote:
>>
>> > Its seems it has something to do with the SW3 client switch. When I
>> > configure a client router on the same segment (VLAN10) it does respond to
>> > the 226.1.1.1,
>> > but what are all those RPF failures?
>> > Why is SW3 not responing?
>> > it almost the same configuration SW3 has configured a IGMP join on the
>> SVI
>> > interface and the router on a physical interface.
>> >
>> > Can anyone help me clarify this
>> >
>> > Kind regards,
>> >
>> > Maarten Vervoorn
>> >
>> >
>> >
>> > 2010/8/5 Maarten Vervoorn <mr.vervoorn_at_gmail.com>
>> >
>> >> Hi group,
>> >>
>> >> I have set up a simple multicast network. But somethings seems to be
>> >> failing. I think its a silly mistake but I can;t find it. Maybe you can
>> help
>> >> me out here?
>> >> Setup:
>> >> SW3
>> >> |
>> >> ---------------------------vlan10 (10.10.10.0/24)
>> >> | |
>> >> SW1 SW2
>> >> | |
>> >> ----------------------------vlan20 (10.10.20.0/24)
>> >> |
>> >> SW4
>> >>
>> >> SW1 and SW2 are multicast routers, SW1 is the RP and mapping agent
>> >> (loopback, 10.10.110.1)
>> >> SW3 on vlan 10 is the multicast client (226.1.1.1)
>> >> SW4 in vlan 20 is the multicast source
>> >> Only the vlan interfaces of SW1 and SW2 are configured sparse mode (with
>> ip
>> >> pim autorp listener)
>> >>
>> >> When I ping from SW4 to group 226.1.1.1 it is failing.
>> >> On SW1 I see RPF failures
>> >> show ip mroute count
>> >> Group: 226.1.1.1, Source count: 1, Packets forwarded: 136, Packets
>> >> received: 231
>> >> RP-tree: Forwarding: 0/0/0/0, Other: 0/0/0
>> >> Source: 10.10.20.40/32, Forwarding: 136/1/1/0, Other: 231/230/0
>> >> Group: 224.0.1.39, Source count: 1, Packets forwarded: 0, Packets
>> received:
>> >> 15
>> >> Source: 10.10.110.1/32, Forwarding: 0/0/0/0, Other: 15/15/0
>> >> Group: 224.0.1.40, Source count: 1, Packets forwarded: 0, Packets
>> received:
>> >> 15
>> >> Source: 10.10.110.1/32, Forwarding: 0/0/0/0, Other: 15/15/0
>> >>
>> >> It looks like SW2 has a RPF failure to the RP but I can't see what it is
>> >>
>> >> (*, 226.1.1.1), 00:32:16/stopped, RP 10.10.110.1, flags: SJCF
>> >> Incoming interface: Vlan20, RPF nbr 10.10.20.10
>> >> Outgoing interface list:
>> >> Vlan10, Forward/Sparse, 00:01:26/00:02:35
>> >> (10.10.20.40, 226.1.1.1), 00:24:28/00:02:54, flags: FT
>> >> Incoming interface: Vlan20, RPF nbr 0.0.0.0
>> >> Outgoing interface list:
>> >> Vlan10, Forward/Sparse, 00:24:28/00:02:35
>> >> (*, 224.0.1.39), 00:40:50/stopped, RP 0.0.0.0, flags: DC
>> >> Incoming interface: Null, RPF nbr 0.0.0.0
>> >> Outgoing interface list:
>> >> Vlan20, Forward/Sparse, 00:40:50/00:00:00
>> >> Vlan10, Forward/Sparse, 00:40:50/00:00:00
>> >> (10.10.110.1, 224.0.1.39), 00:01:53/00:02:14, flags: PTX
>> >> Incoming interface: Vlan20, RPF nbr 10.10.20.10
>> >> Outgoing interface list:
>> >> Vlan10, Prune/Sparse, 00:00:54/00:02:06
>> >> (*, 224.0.1.40), 00:40:58/stopped, RP 0.0.0.0, flags: DCL
>> >> Incoming interface: Null, RPF nbr 0.0.0.0
>> >> Outgoing interface list:
>> >> Vlan20, Forward/Sparse, 00:40:58/00:00:00
>> >> Vlan10, Forward/Sparse, 00:40:58/00:00:00
>> >> (10.10.110.1, 224.0.1.40), 00:36:11/00:02:33, flags: PLT
>> >> Incoming interface: Vlan20, RPF nbr 10.10.20.10
>> >> Outgoing interface list:
>> >> Vlan10, Prune/Sparse, 00:01:26/00:01:34
>> >> SW2 has rp mappings
>> >> SW2#sh ip pim rp map
>> >> PIM Group-to-RP Mappings
>> >> Group(s) 224.0.0.0/4
>> >> RP 10.10.110.1 (?), v2v1
>> >> Info source: 10.10.110.1 (?), elected via Auto-RP
>> >> Uptime: 00:45:27, expires: 00:02:10
>> >> !
>> >> SW2# show ip mroute count
>> >> Group: 226.1.1.1, Source count: 1, Packets forwarded: 31, Packets
>> received:
>> >> 2
>> >> RP-tree: Forwarding: 0/0/0/0, Other: 0/0/0
>> >> Source: 10.10.20.40/32, Forwarding: 31/1/4/0, Other: 2/1/0
>> >> Group: 224.0.1.39, Source count: 1, Packets forwarded: 2, Packets
>> received:
>> >> 4
>> >> Source: 10.10.110.1/32, Forwarding: 2/0/48/0, Other: 4/2/0
>> >> Group: 224.0.1.40, Source count: 1, Packets forwarded: 3, Packets
>> received:
>> >> 7
>> >> Source: 10.10.110.1/32, Forwarding: 3/-1/48/0, Other: 7/2/2
>> >> SW2# show ip route
>> >> Gateway of last resort is not set
>> >> 10.0.0.0/8 is variably subnetted, 4 subnets, 2 masks
>> >> C 10.10.10.0/24 is directly connected, Vlan10
>> >> C 10.10.20.0/24 is directly connected, Vlan20
>> >> O 10.10.110.1/32 [110/2] via 10.10.20.10, 00:00:01, Vlan20
>> >> [110/2] via 10.10.10.10, 00:00:01, Vlan10
>> >
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Received on Fri Aug 06 2010 - 01:09:40 ART