Anycast 101

Fri Dec 17 12:11:53 UTC 2004

On 17-dec-04, at 12:25, Stephane Bortzmeyer wrote:

>> but even if 5 or 8 or 12 addresses become unreachable the timeouts
>> get bad enough for users to notice.

> We can turn this into a Good Practice: do not put an instance of every
> root name server on any given exchange point.

> Actually, this is only a theoretical issue, the current maximum seems
> to be only three (at the LINX in London).

Well, there may be only three "at" the LINX, but from where I'm 
sitting, 7 are reachable over the AMS-IX, 4 over ISP #1 and 1 over ISPs 
#2 and #3, respectively.

Interestingly enough, b, c, d and f all share this hop:

  6  portch1.core01.ams03.atlas.cogentco.com (195.69.144.124)

(195.69.144.0/23 is the AMS-IX exchange subnet.)