[j-nsp] igmp snooping layer 2 querier breaks ospf in other devices

[Aaron Gould]

Thanks Aditya, here's my re-creation of this scenario in my lab... but 
it works with the pim/igmp config that i have, and the ospf neighboring 
over the l2circuit continues to work.  isn't ospf 224 packets "hidden" 
inside encapsulation over l2circuit?  how would pfe in 5048 use 224 
routes seen in inet.0 and inet.1 for l2circuits?


-Aaron


me at lab-5048-2> show route 224/8


inet.0: 846 destinations, 847 routes (846 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

224.0.0.2/32       *[PIM/0] 16:56:50
                       MultiRecv
                     [LDP/9] 16:56:47, metric 1
                       MultiRecv
224.0.0.5/32       *[OSPF/10] 16:56:52, metric 1
                       MultiRecv
224.0.0.13/32      *[PIM/0] 16:56:50
                       MultiRecv
224.0.0.22/32      *[IGMP/0] 16:55:29
                       MultiRecv

inet.1: 6 destinations, 6 routes (6 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

224.0.0.0/24       *[Multicast/180] 16:56:46
                       MultiDiscard

me at lab-5048-2> show route table l2circuit.0

l2circuit.0: 12 destinations, 12 routes (12 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

...

10.123.12.240:NoCtrlWord:5:2056:Local/96
                    *[L2CKT/7] 16:55:35, metric2 2
                     > to 10.123.14.9 via xe-0/0/0.0, Push 64741

10.123.12.240:NoCtrlWord:5:2056:Remote/96
                    *[LDP/9] 16:55:35
                       Discard







On 2/2/2024 10:25 AM, Aditya Mahale wrote:
> When you enabled pim multicast routes are added to the pfe, this is 
> mostly breaking ospf over l2 ckt because these packets are mostly now 
> matching the default 224 routes added to pfe . Without having any show 
> commands or rtsockmon it’s difficult to debug anything
>
> -Aditya
> Google
>
> On Fri, Feb 2, 2024 at 8:21 AM Aaron Gould via juniper-nsp 
> <juniper-nsp at puck.nether.net> wrote:
>
>     I tried to recreate the scenario in my lab with no success
>
>     21.2R3-S4.8 - in lab - problem not seen
>     20.2R3-S7.3 - in lab - problem not seen
>     19.2R3-S6.1 - in lab - problem not seen
>     18.3R3-S6.1 - in lab - problem not seen
>     17.4R2-S11  - in lab - problem not seen
>
>     17.4R2-S11  - in field - problem seen
>
>
>     again, the problem is, when i enabled this command...
>
>     set protocols igmp-snooping vlan vlan100 l2-querier source-address
>     10.100.4.1
>
>     ...a customer riding an l2circuit on ge-0/0/2 report to me that their
>     multicast stops working... ospf goes down and stays in INIT...
>
>     when i remove all pim and igmp, then there OSPF neighbors up and
>     stabilizes
>
>     i just don't know how running igmp inside vlan 100 with ports
>     ge-0/0/4,
>     5 and 6 would have anything to do with an l2circuit on ge-0/0/2
>
>
>     -Aaron
>
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>
-- 
-Aaron