graphs can tell a lot
After contributing my .2ç to this usenet thread i remembered that today i first noticed one of our backbone rings to be split by our DNS graphs.
This is what it looked like:
<img src=”/static/files/ring-split-jumpy-small.png”
What happened is that one part of our recursive servers are situated in Duesseldorf while the other part sits in Frankfurt; both sites are reachable via the same Addresses due to use of iBGP anycast so the load gets split by the l3 routing decision. What we can see above is some of the DNS queries getting shifted from Duesseldorf to Frankfurt because at that time Berlin and eastern Germany were ‘nearer’ to Frankfurt than to Duesseldorf network topology wise because of a fibrecut between Berlin and Hannover.
So, nothing serious happened due to the ring structure, some DNS queries got shifted and some milliseconds added — business as usual you could say, nevertheless fun to watch with these graphs.
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