North American Network Operators Group
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RE: BGP Anywhere - Global Redundancy

  • From: Steve Gibbard
  • Date: Wed Apr 06 21:44:02 2005 
On Wed, 6 Apr 2005, Vandy Hamidi wrote:


I definitely want 100% of traffic going towards the Primary Site during
normal operation.

LocalPref/MED can be controlled by community strings with my direct
peers.  As you said, I'm paying them for the service, but how will the
advertisement behave after it propagates to their upstream peers?  At
that point AS Path should be the only determining factor, yes?
Nope. You're at the mercy of whatever traffic engineering or local-preffing other networks decide to do, and you won't have any control over it.

Are ISP to ISP transit routes manipulated at MED or LocalPref levels?  I
suppose some ISPs may mark some peer with a preferential MED.

Yes.


I was turned on to BGP anywhere when reading up on UltraDNS.  Looks like
they use it for Global load balancing in which a DNS server on the East
Coast will respond to DNS queries to my East Coast DC and the same for
the west coast.  They guarantee 100% DNS response, so I imagine it works
for them.

Has anyone on the list performed BGP Anywhere?  There has to be someone
on Nanog that has done this.
This is more often known as Anycast.

I run the network infrastructure for the PCH Anycast DNS network.

It works well for trying to get traffic to come into multiple places. When we have a site go down, we withdraw the routing announcements from that location.

Trying to get traffic to go to only one place while sourcing BGP announcements from multiple places won't work very well.

-Steve