North American Network Operators Group

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Re: multi-homing fixes

  • From: Valdis.Kletnieks
  • Date: Sat Aug 25 12:22:12 2001

On Sat, 25 Aug 2001 14:55:51 BST, Alex Bligh said:
> One such technology possibly ripe for perversion is DNS. Another
> is mobile IP. Sure, these may not be great for the application right
> now, but they both share a key advantage, which is that the deployer
> pays (not the rest of the internet). Assuming the a fixed % of users
> multihome (and it's likely to increase), and assuming a fixed cost per
> prefix supported (OK, so that's likely to decrease), the costs are
> O(n) rather than O(n^2).

Do you *really* want your DNS TTL set down in the same range as
the time for a BGP route fall-over?

We usually run with hign TTLs, and drop them down before impending
changes.  Unfortunately, there's no easy way to do that 24 hours before
the backhoe gets there...

Also, if you run and drop your DNS TTL, I *do* pay,
because now my DNS server has to hit the network for a look-up for
your site - you just added several packets to the transaction. Given
that we have an on-site Akamai node, for some sites, the DNS lookup
could be 10% of the total traffic on our outbound pipe for each page