Re:What DNS Is Not
by tptacek on Sunday November 08, 2009 @10:45PM
(#930334)
Both the end-to-end principle and the principle of common engineering sense argue against baking content distribution networks into "layer 3" Internet routing:
* Internet routing, particularly interdomain routing, is already overtaxed. Despite the fact that BGP4 is fully capable of doing so, it's still impossible to advertise a "typical" individual IP address (so that you could, for instance, multihome).
* There are as many different CDN service models as there are CDNs, and when you have flexible and changing app requirements, you want to keep the center of balance in the app layer, where it's easy to change.
The problem with Vixie's argument here is that while BGP4 is genuinely a "lower" layer --- where almost any policy innovation needs to be agreed on by multiple billion-dollar corporations --- DNS simply isn't. These stupid global traffic management pet tricks that Vixie is arguing against don't actually break the DNS; they just rob it of its purity of essence.
* Internet routing, particularly interdomain routing, is already overtaxed. Despite the fact that BGP4 is fully capable of doing so, it's still impossible to advertise a "typical" individual IP address (so that you could, for instance, multihome).
* There are as many different CDN service models as there are CDNs, and when you have flexible and changing app requirements, you want to keep the center of balance in the app layer, where it's easy to change.
The problem with Vixie's argument here is that while BGP4 is genuinely a "lower" layer --- where almost any policy innovation needs to be agreed on by multiple billion-dollar corporations --- DNS simply isn't. These stupid global traffic management pet tricks that Vixie is arguing against don't actually break the DNS; they just rob it of its purity of essence.