Melinda, I actually agree with most of what you say in the absolute. I will note that the one thing going for the home network NAT guys is that they have focused on making things work to the extent that they even have George Hamilton selling NATs at the poolside on TV commercials for Circuit City. They may not take routing transparency seriously enough, but they seem to have a real market for their products. The leading NAT gets the follow review on amazon.com: Average Customer Review: <4 stars out of 5> Based on 682 reviews! To that extent, they may have found the right engineering and usability trade-offs for the home LAN scenario and perhaps even the common soho solution. I did not see a single comment in the amazon reviews citing routing issues. I think we can agree that a single protocol for traversal that works for all topologies would be ideal. cheers, peterf -----Original Message----- From: Melinda Shore [mailto:mshore@cisco.com] Sent: Monday, March 18, 2002 2:18 PM To: Peter Ford Cc: ietf@ietf.org Subject: Re: Netmeeting - NAT issue >Ahh, it doesn't have to damage routing transparency. If we were to use >a signaling protocol that is carefully crafted to preserve routing >transparency (e.g. RSVP) then we can avoid this issue. That's what I'm working on, but midcom and upnp as they're currently defined most certainly do have routing-related problems. >The upnp guys are not really thinking of damaging routing transparency. Of course they weren't. But the assumptions that the network is single-homed and that there's only one NAT in the path and that there are no firewall interactions are inherently non- general, and any assumption that they fix "the" problem is necessarily incorrect. Seeing this stuff touted as a general- purpose fix makes me very uncomfortable. Melinda