DOA

This paper essentially suggests an alternate addressing scheme built on top of IP known DOA (delegation oriented architecture). It purports to address the problems created by NAT and firewalls - that is, they violate the principles of the internet. It claims to be better than IPv6, because the addresses do not reflect any kind of network topology (though what is wrong with that, I cannot tell).

The basic idea is that every machine anywhere has a 160-bit EID. These EIDs can be resolved to IPs through the use of a global lookup table. They suggest that this global lookup table be implemented as a DHT. Then, using a NAT or a firewall becomes simple. 1) You send your information (EID to IP mapping) to the NAT or firewall. 2) You place an entry in the EID mapping that maps your EID to the address of the NAT or firewall. After these two steps have been accomplished, a packet destined for your EID will make its way to the NAT or firewall through normal IP routing, and from there to you, with information that your NAT or firewall keeps in its local state.

This allows for some nice things, such as chaining intermediary elements, and the use of intermediate nodes that are not directly on the path between your own machine and other nodes on the internet.

The costs, though, are significant. This system is bad news for latency, since the average amount of time to resolve an EID was on the order of 138 ms. If that is just their test system, then it is reasonable to assume that this would increase (at least a little) for a larger DHT. After having read the paper on DNS performance, which points out that there are a large number of sites that are visited only once, this probably means that the quality of internet users' experiences would suffer at least a little. Most importantly, many connections are short-lived http connections, and users would like their pages to load quickly.

My own personal complaint about this system (which extends beyond the latency problem noted above) is that it essentially imposes a structure on the internet through its use of a DHT to do EID resolution. While it definitely solves the exhaustion of IPv4 addresses, so does IPv6. And they both impose some sort of structure on the internet. For IPv6, that structure is hierarchical addressing. For DOA, it is a DHT across the internet. The hierarchical system has been shown to have at least some merit (as in the case of DNS), whereas a DHT seems like it would suffer from frequent node losses which, while they would not affect correctness, would at the very least affect performance.