On 7/16/07 4:13 AM, "Brian E Carpenter" <brian.e.carpenter@xxxxxxxxx> wrote: > Maybe by a lack of simplicity? Midcom and SIMCO are very simple. I think that there are a few problems, which taken in aggregate make NAT "control" a hard sell. One is that in even modestly complex networks either the application has to be aware of and make decisions about topology or that the traversal mechanism has to be aware of and make decisions about topology. I started the network-friendly midcom stuff (which turned into the NSIS nat and firewall work) because of that, but after having spent more time with it I really think it is not deployable in real networks, which we can talk about some other time. Another problem is the lack of naming and lookup facilities. DNS SRV records are probably going to be as good as it gets. VoIP protocols and others that make use of embedded addresses actually do have an advantage here, because they're able to transmit an acquired address in the application signaling. However, that won't help with servers, P2P, and so on. And, of course, there are heaps of political issues. Some of them are as crude as being about who controls what, but there are some more subtle ones around business models (the last time I talked about this Keith insisted that the "IETF doesn't do business models," and I still encourage him to take a good look at what's going on in what's now the RAI area), as well, that shape the technical decisions that are made. Melinda _______________________________________________ Ietf@xxxxxxxx https://www1.ietf.org/mailman/listinfo/ietf