Question about MPLS L3VPN

[Ondrej Zajicek]

On Sat, Jan 27, 2024 at 01:42:57PM +0100, Marcel Menzel via Bird-users wrote:
> Hello List,
> 
> I am doing a test setup with the new MPLS L3VPN feature (for background
> information: I am running IPsec with L2TP on top, with OSPF as IGP and iBGP
> between loopbacks)
> with one router receiving an IPv6 fulltable via eBGP and the other one
> establishing the BGP session through a tunnel described above, and I noticed
> periodic high CPU usage on the router receiving the routes at the end of the
> tunnel.
> 
> It seems, that BIRD keeps exporting the whole table to the kernel every 30
> seconds, as it is configured in the kernel protocol scan time with the "vrf"
> directive set:

Hello

It is possible that BIRD exports some route but receives back from kernel
something slightly different than it expected, so it will try to re-send
it during the scan.

If you enable 'debug all' on the kernel protocol (both global and in
VRF), you can see:

2024-01-27 14:53:50.313 <TRACE> kernel1v6: 2001:db8:1:2::/64: seen

or:

2024-01-27 14:53:50.313 <TRACE> kernel2v6: 2001:db8:1:2::/64: updating

... and i just noticed that the bug manifests even in my test case, so
i will check it.

-- 
Elen sila lumenn' omentielvo

Ondrej 'Santiago' Zajicek (email: santiago at crfreenet.org)
"To err is human -- to blame it on a computer is even more so."