Hi Inder,

Here are some answers to your questions...

Is this an expected behavior when using the same VR ID across different
> interfaces and FIB tables?


It's not an intended behavior. I would expect things to work with your
setup , but I have never tried using VRs with the same VR ID on
subinterfaces of the same physical interface which are attached to
different FIB tables. I have tested many times with subinterfaces using the
same VR ID on the same physical interface with both subinterfaces using the
default FIB table and that has worked.


> Could this be a known issue or limitation in VPP 24.02?


It's not a known issue. So if you're asking if it might possibly be fixed
in a newer release than 24.02, I don't know. If it was caused as a side
effect of some bug unrelated to VRRP, maybe it works in a newer version.
But the issue has not been specifically addressed since 24.02 because
you're the first person to report it that I know of.

Are there any recommended best practices for handling VRRP instances across
> multiple FIB tables?


There are no documented best practices. One suggestion I can make is to try
using a different VR ID on one of the VRs and see if the behavior changes.

> Please let us know if additional logs, configuration snippets, or packet
> captures would help in analyzing the issue further.
>
Yes, all of that stuff would help :)

If you send the commands you are using to configure VPP, a packet capture
of one of the ping packets being dropped and output of 'vppctl show
hardware-interfaces', that might help me make a better guess on what's
causing the issue.

Thanks,
-Matt



On Thu, Feb 26, 2026 at 8:53 AM Inder via lists.fd.io <inderpalpatheja=
[email protected]> wrote:

> Hi Team,
>
> Dear VPP Community,
>
> We are currently using *VPP version 24.02* and have encountered an issue
> related to VRRP configuration. We would appreciate your guidance on this
> behavior.
> Setup Details
>
>    -
>
>    Two VMs configured in an active/backup redundancy model.
>    -
>
>    A VRRP instance (VR ID 101) is configured on interface eth0.1.
>    -
>
>    eth0.1 is associated with *FIB table 1*.
>    -
>
>    Both VMs participate in this VRRP instance, with one acting as *Master*
>    and the other as *Backup*.
>    -
>
>    In this setup, the Backup VM is able to successfully ping the VRRP VIP.
>
> Issue Observed
>
> When we configure a second VRRP instance with the *same VR ID (101)* on a
> different interface (eth0.2), where:
>
>    -
>
>    eth0.2 belongs to a separate FIB table (FIB table 2),
>
> we observe the following behavior:
>
>    -
>
>    The Backup VM is no longer able to ping the VRRP VIP of the first VRRP
>    instance.
>    -
>
>    This functionality was working correctly prior to configuring the
>    second VRRP instance.
>
> Additional Observation
>
>    -
>
>    After restarting the VPP service, the ping to the first VRRP VIP from
>    the Backup VM starts working again.
>    -
>
>    We understand that using the same VR ID results in the same Virtual
>    MAC address.
>    -
>
>    However, we are unsure why restarting VPP restores correct behavior.
>
> Query
>
>    1.
>
>    Is this an expected behavior when using the same VR ID across
>    different interfaces and FIB tables?
>    2.
>
>    Could this be a known issue or limitation in VPP 24.02?
>    3.
>
>    Are there any recommended best practices for handling VRRP instances
>    across multiple FIB tables?
>
> Please let us know if additional logs, configuration snippets, or packet
> captures would help in analyzing the issue further.
>
> Thank you in advance for your support.
>
> regards
> Inder
>
> 
>
>
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