Configuration now understood. Pim is enabled they are using virtual routing/instances
Thanks
Going into more obscure scenarios, if for some reason in the initial process while the SOURCE is registering to the RP, the PIM Join from RP back... -posted to the "Ask the Expert" community
Re: Multicast routing PIM L3 switches No PIM interfaces configured | | | Going into more obscure scenarios, if for some reason in the initial process while the SOURCE is registering to the RP, the PIM Join from RP back to the FHR does not arrive and/or the RP never sends the PIM Register Stop, certainly the FHR would stay sending multicast traffic encapsulated as unicast, never switching to the native multicast path, and in this situation the only parties that would know what's going on in terms of multicast groups in your L3 topology are the path from the RP down to the RECEIVERs and the path from the SOURCE towards the RP, the routers in transit from SOURCE (FHR) to RP won't know, but that is usually due to configuration issues or software defects.
More plausible scenarios could be due to tunneling as mentioned by Yasmin, or something like Multicast VLAN Registration (MVR).
Regards,
Elvin | | Reply to Group Online View Thread Recommend Forward |
Original Message: Sent: 08-22-2021 14:19 | |
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Original Message:
Sent: 8/23/2021 5:23:00 AM
From: ElvinArias
Subject: RE: Multicast routing PIM L3 switches No PIM interfaces configured
Going into more obscure scenarios, if for some reason in the initial process while the SOURCE is registering to the RP, the PIM Join from RP back to the FHR does not arrive and/or the RP never sends the PIM Register Stop, certainly the FHR would stay sending multicast traffic encapsulated as unicast, never switching to the native multicast path, and in this situation the only parties that would know what's going on in terms of multicast groups in your L3 topology are the path from the RP down to the RECEIVERs and the path from the SOURCE towards the RP, the routers in transit from SOURCE (FHR) to RP won't know, but that is usually due to configuration issues or software defects.
More plausible scenarios could be due to tunneling as mentioned by Yasmin, or something like Multicast VLAN Registration (MVR).
Regards,
Elvin
Original Message:
Sent: 08-22-2021 14:19
From: MIKE WRIGHT
Subject: Multicast routing PIM L3 switches No PIM interfaces configured
Hiya Yasmin
What you are saying in your initial paragraph seems right to me.
We basically only have RP and groups being advertised in routing instance.
My opinion is this is a poor configuration, do you confirm.
Regards
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MIKE WRIGHT
Original Message:
Sent: 08-21-2021 22:52
From: Yasmin Lara
Subject: Multicast routing PIM L3 switches No PIM interfaces configured
Hi Mike,
Initially, the multicast traffic is tunneled from the sending side router to the RP as unicast traffic with destination address = RP. That could get to the RP without PIM enabled on the interfaces. However, on the receiving side, the router that receives an IGMP message from the client, sends PIM join message towards the RP, and that requires PIM enabled interfaces all the way to the RP.
My guesses:
- The switches are flooding the multicast traffic (at L2)
- You are using something like draft rosen and the multicast traffic is being encapsulated in GRE.
Regards,
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YASMIN LARA
Technical Marketing Engineer
JNCIE-SP, JNCIE-ENT, JNCIE-DC, JNCIE-SEC
JNCDS-DC, JNCIA-DevOps, JNCIP-CLOUD
Original Message:
Sent: 08-20-2021 09:11
From: MIKE WRIGHT
Subject: Multicast routing PIM L3 switches No PIM interfaces configured
Hiya
I studied PIM a while ago and the new company Im working at is using multicast for video streaming.
The have configured the core switch to be the RP and are then advertising several multicast groups(subnets) and the RP via a routing instance.
They are using OSPF for the routing between the L3 switches so all switches are aware of the multicast groups and RP.
I have run show pim interfaces on many of the L3 switches and it say the pim instance does not exist, in other words the switches havent been enabled for PIM
Some how they are still routing multicast traffic. Would this be because the receives look at their local switch (and has the routes) will route to the RP regardless.
I would have thought there would be a PIM tree if it is not enabled on any of these switches.
Thanks
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MIKE WRIGHT
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