[dns-operations] anycasting for fun and profit

[Jim Reid]

On 16 Oct 2012, at 03:48, Bill Woodcock wrote:

> The big problem comes if you select different transit providers in  
> different locations.  That's what Patrick is alluding to when he  
> says that London queries can be directed to Tokyo servers…  Network  
> operators will always deliver to a customer rather than a peer, even  
> if they have to haul halfway around the world to do so.

+1.

When Nominum ran an anycast service 10-12 years ago, I saw my DNS  
queries from Scotland wave hello to the anycast node at LINX as they  
passed through the LINX backplane on their way to a node in  
California. The reason for that was my ISP at the time didn't peer or  
have some other form of agreement with Nominum's transit provider(s)  
at LINX but did at PAIX. Another issue back then was some LINX members  
wouldn't peer with members who had less than a /20(?) of space and  
Nominum's anycast /24 was considered to be too small to be allowed to  
mingle with the grown-ups. This should be less of a concern nowadays  
since anycasting is so widely used.

Bill, you no doubt remember those details far better than I do. :-)