IP Multicast Persistent Duplicate Packet Issue

Wed Apr 6 23:07:34 UTC 2022

Thanks Jared. Yes it is SSM. I will try to flip PIM priority and align HSRP
active.

My initial thought was keeping everything as it is. Can I simply flip PIM
assert winner to PE1. Same way we can manually select STP root. Looks like
this is probably not an option. Didn't find relevant doc on how to
manipulate PIM assert winner in Cisco boxes though. Highest IP is the
winner if IGP costs are the same to the source.

R

On Thu, Apr 7, 2022 at 3:02 AM Jared Mauch <jared at puck.nether.net> wrote:

> If this is ASM, what device is the RP?  You may want to configure MSDP
> between PE1/PE2 to help if that’s the case, or is this SSM or something
> else you may want to just flip the PIM priority to make it pick what you
> want and see if you can tie it to your HSRP (Cisco, might I suggest VRRP so
> you could do dual-vendor later?) state, perhaps with EEM script to keep the
> config in sync if required.
>
> - Jared
>
> > On Apr 6, 2022, at 3:25 AM, Roman Islam <romislam at gmail.com> wrote:
> >
> > Hi Everyone,
> >
> > Has anyone experienced a TETRA Radio application issue if underlying IP
> multicast transport sends persistent duplicate packets?
> >
> > Here is my scenario as below:
> >
> > PIM is running on the MPLS L3 VPN environment. C multicast is running on
> a single VRF (TETRA) only. Source is running behind a dual home PE. HSRP,
> PIM DR path is via PE1 to the source. Anycast RP is configured with PE1 &
> PE2.
> >
> > On the receiver side there is a single PE. When I check (S,G) route on
> the receiver side PE default MDT is working as expected. After the
> threshold exceeds it switches to the data MDT. PIM Assert mechanism winner
> is PE2 though (Since PE 2 has the highest IP and source is behind dual home
> PE with equal cost I guess).
> >
> > Can this be a reason for persistent duplicate multicast packets at the
> receiver side; since the assert winner is PE2 but HSRP, PIM DR path is via
> PE1 to the source?
> >
> > If this is the case is there any way to manually configure the assert
> winner to PE1?
> >
> > Roman
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.nanog.org/pipermail/nanog/attachments/20220407/acd00388/attachment.html>