IPv6 Address allocation best practises for sites.

Aleksi Suhonen nanog-poster at axu.tm
Tue Sep 25 05:20:01 UTC 2012


The way to allocate IPv6 addresses per website depends more on the 
technologies already in use at the hosting site. An existing hoster will 
move slowly to any alternative method.

I predict a bigger, faster change in the way medium sized sites do load 
balancing. IPv6 allows hosters to go back to DNS round robin based load 
balancing, which still works much better than often reported. It became 
an unfashionable way to do things because there weren't enough IPv4 
addresses for everyone to be doing it, but this limitation won't be an 
issue in IPv6.

I had a customer case a couple of years back where the client tried it 
out and was amazed at the results. In that particular case each server 
announced 2 /128s to the closest router, one with a better metric and 
the other with a worse metric. So during failovers, one server got twice 
the normal traffic until that DNS entry was pulled from the round robin set.

Said client went back to "the old ways" tho because they couldn't do the 
same thing on IPv4 and they didn't want to have two different load 
balancing methods for two different IP versions. They are very fervent 
believers in the KISS principle. They are now waiting and hoping for the 
IPv4 traffic to die down and IPv6 traffic to pick up so that they can 
start doing things on IPv6's terms instead. :-)

Hoping against all odds that they won't have to wait long,

         Aleksi Suhonen / Axu TM Oy
         Internetworking Consulting
         Cellular: +358 45 670 2048
         World Wide Web: www.axu.tm

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