> -----Original Message-----
> From: NANOG [mailto:nanog-boun...@nanog.org] On Behalf Of Christopher
> Morrow
> Subject: Re: AWS Elastic IP architecture
> [...]
> i sort of doesn't matter right? it is PROBABLY some form of encapsulation
> (like gre, ip-in-ip, lisp, mpls, vpls, etc) ...
> [...]

I don't know how the public blocks get to the datacenter (e.g. whether they are 
using MPLS) but after that I think it is pretty straightforward. All of the VMs 
have only one IPv4 address assigned out of 10/8. This doesn't change when you 
attach an Elastic IP to them.

All that is happening is that they have some NAT device somewhere (maybe even 
just a redundant pair of VMs?) that has a block of public IPs assigned to it 
and they are static NAT'ing the Elastic IP to the VM. They control the 
allocation of the Elastic IPs, so they just pick one that is routed out of that 
datacenter already. They probably don't need to do anything out of the ordinary 
to get it there.

(See: http://aws.amazon.com/articles/1346 )

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