Questions about anycasting setup

Sat Mar 10 06:16:25 UTC 2012

Thanks for guidance everyone!

Appreciate it.

And yes, I can see another thread running on discussion about /48 - I am
listening silently about it.

Multiple AS doing anycasting was little concern for me, but now seems good
since I can see everyone's suggestion to use single own ASN for anycasting.

On Fri, Mar 9, 2012 at 3:25 PM, Pete Carah <pete at altadena.net> wrote:

> On 03/09/2012 01:34 AM, Elmar K. Bins wrote:
> > Re Bill,
> >
> > woody at pch.net (Bill Woodcock) wrote:
> >
> >>> Well, let's say, using Quagga/BIRD might not really be best practice
> for
> >>> everybody... (e.g., *we* are using Cisco equipment for this)
> >> How does your Cisco know whether an adjacent nameserver is heavily
> loaded, and adjust its BGP announcements accordingly?
> > It doesn't have to.
> >
> > I don't know how you guys do it, but we take great care to
> > keep min. 70% overhead capacity during standard operation.
> >
> My point had to do with resilience in the face of hardware/OS/software
> failures in the box providing the
> service.  Bill's has more to do with resilience in the face of other
> network events (e.g. the upstream for one
> of the boxes has a DDOS; you cannot reasonably provide enough excess
> capacity to handle that...)  Neither of these is addressed by using a
> separate router to announce the server's anycast route.  (unless somehow
> the Cisco is providing the anycasted service, which would address my
> concern but still not Bill's.)
>
> Also, Bill is probably talking root (or bigger public) servers whose
> load comes from "off-site"; the average load characteristics for those
> are well known but there can be extremes that would be hard to plan for
> (hint - operating at 30% isn't really good enough, probably not 10%
> either.  Bill (and the other Bill) have pretty good stats for this that
> I've only glanced at...)  And it is easy to see where one of the
> extremes might hit only one or two of the anycast instances.  He implies
> having the instances talking to each other in background to adjust bgp
> announcements to maybe help level things.  Fortunately at least for the
> root servers, the redundancy is at two levels and anycast is only one of
> them.
>
> -- Pete
>
>
>

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