North American Network Operators Group

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Re: /8 end user assignment?

  • From: Iljitsch van Beijnum
  • Date: Fri Aug 05 06:06:49 2005

On 5-aug-2005, at 11:33, Bruce Campbell wrote:

Is there any particular reason why a service over IPv6 couldn't be load balanced by putting a good number of AAAA records in the DNS?

_Eventually_, DNS packet size and a desire to avoid truncation at that level would stop you. Nothing stopping you from having say 4 As and 3 AAAAs attached to one www record though.
Note that the issues for regular requests are very different from those that make adding AAAA record to the root servers more difficult.

Since clients are either asking for A or AAAA in any given request, the two won't generally sit together in the same packet.

I'm not sure how much room additional AAAA records take up, but I think it's a little under 30 bytes. At this rate, there is no way you're going to run out of 512 bytes with less than 10 AAAA records. Then there is EDNS0, and failing that, TCP.

Personally, I think that having two AAAA records will hold you in place for long enough that vendors will catch up with decent AAAA load balancing support, unless of course you get hit by the mythical IPv6 killer app in the meantime.
Mythical killer apps only need mythical bandwidth so a mythical load balancer suffices. :-)