Devil's Advocate - Segment Routing, Why?

Baldur Norddahl baldur.norddahl at
Sat Jun 20 09:27:29 UTC 2020

On Sat, Jun 20, 2020 at 11:08 AM Mark Tinka <mark.tinka at> wrote:

> > MPLS with hierarchical routing just does not scale.
> With Internet in a VRF, I truly agree.
> But if you run a simple global BGP table and no VRF's, I don't see an
> issue. This is what we do, and our scaling concerns are exactly the same
> whether we run plain IP or IP/MPLS.
> Mark.
We run the Internet in a VRF to get watertight separation between
management and the Internet. I do also have a CGN vrf but that one has very
few routes in it (99% being subscriber management created, eg. one route
per customer). Why would this create a scaling issue? If you collapse our
three routing tables into one, you would have exactly the same number of
routes. All we did was separate the routes into namespaces, to establish a
firewall that prevents traffic to flow where it shouldn't.


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