Supporting LOC RR's

[Timothe Litt]

On 12-Apr-22 14:15, Philip Prindeville wrote:
> In my case, I do split-horizon for my domain in-house and use RFC-1918 addresses, so leaking them with the internet would be pointless anyway.

I have separate LOC records for in-house and external views.  The 
in-house version is high precision.  The external version is fuzzed.

I use LOC records on domains; the comparison with IP geolocation is 
because the usual alternative to LOC is to translate the domain name to 
an IP address; then geolocate that using one of the commercial databases.

Of course, that gets tricky when a hostname has multiple IP addresses or 
is served by anycast (such as a CDN).  In that case, the semantics 
aren't obvious - should the location be that of the CDN server (and 
which one)? The origin server?  And with 1918/NAT, the origin server may 
be in different locations depending on the protocol used.  (E.g. one 
public IP address, with an SMTP server in one building and a WWW server 
in another)

With WPs, you're not trying to locate a host at all; you're trying to 
infer (or calculate) the mobile device client's location.  Or assist the 
mobile device to calculate its location.

It's not clear to me that it's less work to prepopulate LOC records than 
to put a cellphone on top of the WAP before turning it on, getting the 
GPS coordinates (e.g. see the 'gpstest' app), and pasting them into the 
WAP's configuration.

If you really want cm scale accuracy, you need some kind of surveying 
instrument - whose data has to go someplace - be it LOC or the WAP 
configuration.  Or the new AP figures out its location based on 
triangulating from existing APs that somehow are deemed trustworthy.  
THEY might have LOC records to help, but that's not pre-provisioning.  
Maybe the new AP could then publish a LOC record with its location to 
help clients.  But I don't see how pre-provisioning helps setting up a 
new AP in this case; you might do the survey before the WAP arrives, but 
once the survey instrument reports a position, you either have prepared 
a configuration file for it (usual case), or you have to find it & 
configure it at that point.  Either way, setting the location is the 
smallest part of setting up a configuration - VLANs, SSIDs, access 
control/portals take much more work.

Anyhow, it's not clear exactly what problem you're asking LOC (or 
anything) to solve.

BTW, RFC1876 is worth reading for the suggested search algorithms.  I 
don't think it ever moved from "experimental", which may be part of why 
uptake hasn't been great.

Timothe Litt
ACM Distinguished Engineer
--------------------------
This communication may not represent the ACM or my employer's views,
if any, on the matters discussed.


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