Resilience - How many BGP providers

Tore Anderson tore at
Thu Nov 12 08:11:38 UTC 2009

* adel at

> - I could ask the question as to whether I can peer with separate
> routers on each of the upstreams.  i.e. to protect against router
> failures on their side.

If you're getting transit from two different upstreams, you're pretty
much guaranteed to be connected to two different routers.  Unless you're
thinking about establishing redundant connections to each provider, that is.

What you should ensure, though, is that the PoPs of the two upstreams
are not found in the same physical building (or neighbourhood for that
matter), and that the fibres that connects you to those PoPs never
cross - it doesn't really help that much with two trenches on each side
of your building if the paths converge 1km away from it.  You might also
want to consider getting the fibres from two different providers to
guard against contract-related disputes, unexpected bankruptcies, or
similar that would cause the fibre provider to terminating/suspending
your service.

> - I will make sure that neither upstream peers with the other
> directly.

This does not make any sense, if you're talking about peering.  Peering
is a good thing for reliability and performance.  I see from the rest of
your e-mail that you're mixing up the terms peering and transit, though,
so if you're taking about your provider A purchasing transit from
provider B, it makes perfect sense - at least if provider A is _only_
getting transit from B.  If on the other hand provider A is getting
transit from C, D, and E in addition to B, it's not really a problem.

It might also be the case that A and B both get transit from C only,
which would make C a single point of failure for you.

Best regards,
Tore Anderson
Redpill Linpro AS -
Tel: +47 21 54 41 27

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