Re: [Geopriv] Confirmation of GEOPRIV IETF 68 Working Group Hums

DHCP is not a great choice in a mobile environment and also not when it 
comes to more complex location representations.

Ciao
Hannes

Brian Rosen wrote:
> 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:[email protected]]
>> Sent: Thursday, April 19, 2007 6:39 PM
>> To: James M. Polk; Dawson, Martin; John Schnizlein; Andrew Newton
>> Cc: GEOPRIV WG; [email protected]; 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:[email protected]]
>>> Sent: Thursday, April 19, 2007 5:31 PM
>>> To: Dawson, Martin; John Schnizlein; Andrew Newton
>>> Cc: GEOPRIV WG; [email protected]; 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
>>>
>>>
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>>>
>>>       
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>
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