In the example you gave the Hilton is EXACTLY the network that MUST give you your location, and Verisign, if they tried, would give a valid, but very wrong location. That is the point of using DHCP for location, you need the closest possible server to get the right location. You need a server that understands the L2 to which you are connected. Anything L3 and farther has a big problem of where, exactly, are you? The proposals for L7 versions of location configuration protocols suffer mightily from the problem of figuring out where you are in the L2. They have to go to great lengths to determine some kind of identifier that they can unambiguously use to figure that out. I think we have (painfully) figured out a way though that morass that will work in enough circumstances to be interesting, but it remains hard, very hard, to identify the L2 when your server is sitting at L7. So, make sure that when you go to the Hilton that you use it's location server, or you may have a big problem if you have to make an emergency call (or even order a pizza). DHCP is an excellent choice for a location server for networks where the DHCP infrastructure is present, and can reasonably be upgraded. The L7 guys point out, correctly, that that's a tall order in a lot of interesting networks. I think that is right. I do think they believe L7 works on every network. I'm certain it doesn't. That's why the compromise of BOTH is probably required. I know it's the only way we are going to get anything done in the next year. Brian > -----Original Message----- > From: Hallam-Baker, Phillip [mailto:pbaker@xxxxxxxxxxxx] > Sent: Thursday, April 19, 2007 6:39 PM > To: James M. Polk; Dawson, Martin; John Schnizlein; Andrew Newton > Cc: GEOPRIV WG; ietf@xxxxxxxx; Allison Mankin > Subject: RE: [Geopriv] Confirmation of GEOPRIV IETF 68 Working Group Hums > > DHCP is a layer 3 technology that talks directly to layer 2. > > This is entirely acceptable, useful and right for NETWORK configuration. > DHCP is an entirely sensible means of obtaining an IP address and > _proposals_ for domain name prefixes and DNS servers. > > DHCP should not be used for any other purpose. In particular to make use > of DHCP for application configuration is a layer violation. Layer 7 should > NEVER communicate with Layer 2 directly. When that happens we lose all the > power and flexibility built into the IP stack. > > > To give a concrete example of the problems caused. I am currently typing > on a VeriSign machine in an office in VeriSign corporate HQ. In that > environment the local DHCP server could provide me with useful and valid > suggestions for all manner of services. But its still the wrong > technology. > > The problem is that when I take the machine to the Hilton Garden Inn down > the road where I am staying I explicitly DO NOT want the hotel network to > provide any more than an IP address. I am not going to use their DNS > server and I certainly don't want to make use of any email server, DNS > prefix, GEOPRV or any other application layer feature they might want to > foist onto me. > > I am using the Hilton Garden Inn LAN, I am not joining their network. The > machine is remaining on the VeriSign network. > > > DHCP is a fine technology for the task DHCP is designed to do. It is an > inappropriate technology for application or service configuration. The > proper infrastructure to support those needs is DNS, supplemented if > necessary by HTTP or LDAP backing store (i.e. either discover the services > via DNS directly or use DNS to discover where the directory service is to > be found). > > Looking at the history of UPnP and Zero Config it strikes me that > attempting to manage networks through peer to peer broadcast or multicast > have been a bust precisely because of this layer violation. > > > > -----Original Message----- > > From: James M. Polk [mailto:jmpolk@xxxxxxxxx] > > Sent: Thursday, April 19, 2007 5:31 PM > > To: Dawson, Martin; John Schnizlein; Andrew Newton > > Cc: GEOPRIV WG; ietf@xxxxxxxx; Allison Mankin > > Subject: RE: [Geopriv] Confirmation of GEOPRIV IETF 68 > > Working Group Hums > > > > At 04:20 PM 4/19/2007, Dawson, Martin wrote: > > >"DHCP is not adequate because it doesn't meet multiple sets of > > >requirements as documented multiple times ..." > > > > bologna > > > > "documented multiple times" means in individual submissions > > > > of which, zero facts were presented to substantiate > > > > If DHCP were so inadequate, why is the DSL forum now going to > > specify it? Why does PacketCable define it? These were > > fairly recent moves... > > > > And, how many times has HELD been presented as if it were a > > product of an IETF WG? > > > > James > > > > > > _______________________________________________ > > Ietf mailing list > > Ietf@xxxxxxxx > > https://www1.ietf.org/mailman/listinfo/ietf > > > > _______________________________________________ > Ietf mailing list > Ietf@xxxxxxxx > https://www1.ietf.org/mailman/listinfo/ietf _______________________________________________ Ietf@xxxxxxxx https://www1.ietf.org/mailman/listinfo/ietf