[c-nsp] BGP ORR - experiences

[Darko P]

Thank you for the feedback!

By "other vendors," do you mean Cisco/Nokia?

We have a similar scenario with over 30 regions, so this kind of sparks my
imagination.
We don't have that many routes in our backbone, and we tend to keep FIRT at
the edge, with just ~100k peering routes in the core, so we could actually
go with hardware.
Which Junos release are you running on the RRs? The reason I'm asking is
because they made some changes in 23.x regarding orr.

Again, thanks for your feedback! Much appreciated.

Cheers,

Darko

On Wed, Oct 15, 2025 at 7:23 AM Saku Ytti <saku at ytti.fi> wrote:

> We use ORR and add-path 3 (to enable ECMP and to have backup) with
> about 40 ORR perspectives and +15M RIB. But this is Junos running on
> compute.
>
> You really want compute, not actual router hardware as the CPU gains
> from modern compute are very significant.
>
>
> I expected we'd have some rearing problems doing this, but it's been
> basically problem free since we started about 4 years ago, compared to
> the significant amount of issues we had due to full-mesh prior to it.
> At the time of doing this, we had some of our other vendors say flatly
> 'no' to the idea of having 40 ORR views with the RIB scale we have.
>
>
>
> Juniper limits the BGP window by default to 16kB, which you can raise
> to 64kB, but we'd really want window scaling support too, as our
> initial convergence is still bound by the TCP window.
>
> On Tue, 14 Oct 2025 at 20:17, Darko P via cisco-nsp
> <cisco-nsp at puck.nether.net> wrote:
> >
> > Hi everyone,
> >
> > I just wanted to ask about experiences with running BGP ORR, or if anyone
> > actually uses it.
> >
> > I know Cisco faced significant issues with the ASR9K, and they always
> > recommended using different silicon if you want to implement BGP ORR.
> >
> > At that time, we couldn't run BGP ORR because we had only 9k's, which was
> > out of the question due to their ongoing issues. Now that it's time to
> > replace the 9k with something else, I wanted to get your thoughts.
> >
> > Cheers,
> >
> > Darko
> > _______________________________________________
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>
>
>
> --
>   ++ytti
>