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Re: Traffic Engineering
"Jay R. Ashworth" <firstname.lastname@example.org> writes: > Are there any major potholes in this theory that I'm missing? Well, you have two technical problems to solve: firstly, the same numbering problem that anyone else has, viz. addresses will change. Secondly, you have a traffic attraction/traffic dispersion problem for non-local connectivity. You also have to provide better value-for-money than the classical hierarchy-of-providers model your competitors will be using. The "classical" approach is to renumber to solve the first case and do the oh-so-fun BGP tricks Dennis Ferguson described here a couple of incarnations ago. A better approach to both problems is to use NAT to deal with the renumbering issue, and large-scale NAT to deal with your border problem (you not only want to reduce the number of prefixes you advertise outbound, and use the DNS to offer back different topolical locators (i.e., IP addresses) for the things connected to you, but you also want to reduce the amount of information you take in from the outside world). To deal with connectivity failures outside the NATs themselves you build tunnels through working inside or outside infrastructure between your NATs. This is straightforward and is what is done now. Dealing with the failures of the NATs themselves requires synchronized or deterministic address mappings, NAT-friendly higher-layer protocols, and a simple IGP. With some performance-affecting trade-offs you can deal with many NAT-unfriendly higher-layer protocols in various ways too, mostly by sharing state information among your border NATs. Sean.