Subject: LLDP-MED and Phone BCP (Re: [Ecrit] New phonebcp draft was submitted)

From: [email-masked]
Date: Mon, 26 Jun 2006 13:33:10 -0400

Brian, list, 

> ... I think we want to have a discussion on whether LLDP-MED is on that list.

As might be expected, I definitely support LLDP-MED as one on that list of 
location methods.  Some key points in favour I believe are: 

o LLDP-MED works at Layer 2, which is where real location comes from. 
Closest to source is better. 

o Access network elements (L2 switches typically) need to be configured 
anyway, and while the admin is touching them, location can be entered 
readily. 

o Wire map associated with L2 access needs to be created and maintained 
anyway.  (DHCP method would require it to be put in a different, possibly 
unrelated dB.) 

o Simple and direct, no intermediate mechanisms needed. (Eg. no need to 
turn on DHCP relay, insert DHCP relay agent sub-options, etc.)  Less 
dependancies is better. 

o No need for any additional interfaces in LLDP-MED method -- all 
interfaces are already defined.  In DHCP method (and presumably L7 also ?) 
an interface to DHCP server, to interface to the wiremap dB, would need to 
be defined to have a fully standards-based approach.   (In LLDP-MED, the 
wiremap dB interface is effectively done through SNMP and the defined 
MIBs, and the data becomes distributed across the L2 infrastructure.) 

o Can be made to work with wireless mobility as well.  Currently, LLDP-MED 
can locate down to the Access Point only (since the wireless environment 
does not yet have a standard way to do triangulation or similar), however 
would be relatively straight-forward to extend to higher accuracy.  (DHCP 
is completely inappropriate for wireless mobility IMHO.) 

Personally, I think above points make best case to use LLDP-MED in a 
managed enterprise environment.  That's a BIG market segment!  Other 
methods may be more appropriate in different environments. 

BTW for those not familiar, among many other things, LLDP-MED provide an 
L2 mechanism for location conveyance, 100% data compatible by design with 
the DHCP methods (both geolocation and civic).  The spec, (formally 
ANSI/TIA-1057), can be found at: 
 
http://www.tiaonline.org/standards/technology/voip/documents/ANSI-TIA-1057_final_for_publication.pdf

Cheers,
Peter Blatherwick

"Rosen, Brian" <[email-masked]>
26.06.06 10:13

        To:     <[email-masked]>
        cc: 
        Subject:        [Ecrit] New phonebcp draft was submitted

I submitted an update to the phonebcp draft before the deadline.  I 
incorporated nearly all of the changes suggested on the list.  I did not 
add a lot of wording about frequency of calls from mobiles as suggested by 
James.  I also did not delete the section on specific protocols phones 
must implement for location acquisition as suggested by Patty.  I'll bring 
up that issue at the meeting; basically, I believe we must have a list 
that all phones must implement, and access network must choose one from 
that list.  Otherwise, we will have no interoperability.  The list at 
present would be DHCP and the L7 protocol (HELD or whatever).  I think we 
want to have a discussion on whether LLDP-MED is on that list.

Until it appears in the archives, you can find it at:
http://www.brianrosen.net/internet-drafts/draft-rosen-ecrit-phonebcp-01.txt
http://www.brianrosen.net/internet-drafts/draft-rosen-ecrit-phonebcp-01.html

Brian

_______________________________________________
Ecrit mailing list
[email-masked]
https://www1.ietf.org/mailman/listinfo/ecrit

_______________________________________________
Ecrit mailing list
[email-masked]
https://www1.ietf.org/mailman/listinfo/ecrit

---

From: "Rohan Mahy" <[email-masked]>
Date: Thu, 29 Jun 2006 15:29:50 -0700

Hi Peter,

Some comments inline.  To be clear, I do not have a strong feeling about
what does on Brian's list or not.  I think LLDP-MED is a completely
reasonable thing for a wired phone vendor to implement on enterprise class
phones.

>  Closest to source is better.

...As opposed to working at the application layer, where real application
security comes from.  Closer to the application is better?   I don't want to
have a debate about layer 2 vs. layer 7 location here, just point out that
the answer you get depends on what you are willing to tradeoff.

> anyway.  (DHCP method would require it to be put in a different, possibly

I'll point out that in the wireless case, the location of the station is
also often in an unrelated place to the the L2 access device.

o Simple and direct, no intermediate mechanisms needed. (Eg. no need to turn
> on DHCP relay, insert DHCP relay agent sub-options, etc.)  Less dependancies
> is better.
>
> wiremap dB interface is effectively done through SNMP and the defined MIBs,
> and the data becomes distributed across the L2 infrastructure.)
>
> would be relatively straight-forward to extend to higher accuracy.  (DHCP is
> completely inappropriate for wireless mobility IMHO.)
>

LLDP-MED does not work in an 802.11 wireless LAN environment.  The
assumptions made in LLDP-MED about link reliability, authentication,
bandwidth availability, timing, and lack of mobility are grossly
inappropriate in a WLAN environment.

IEEE 802.11 Task Group V is working on a Layer 2 approach of their own,
which is significantly better than LLDP-MED on these regards:

ftp://ieee:[email-masked]/11/06/11-06-0010-01-000v-location-presentation.ppt
ftp://ieee:[email-masked]/11/06/11-06-0009-03-000v-location-proposal.doc

There were still some big issues in the posted version.  I provided a bunch
of comments to one of the authors after that version was published, at the
last 802.11 interim.  I would expect the draft will be updated shortly
before the next 802.11 plenary in San Diego (the week after IETF 66).

Personally, I think above points make best case to use LLDP-MED in a managed
> enterprise environment.  That's a BIG market segment!  Other methods may be
> more appropriate in different environments.
>

I am personally much more interested in location (emergency and otherwise)
for wireless LAN devices than for wired devices.  The user of a wireless LAN
device is much less likely to know their own location than a user of a wired
LAN devices.  This is a fast growing market segment because people want
mobility once the price is right and the quality is good enough.  Yes, we
need to solve wired location, but lets not forget the wireless communities.

thanks,
-rohan

---

From: Andrew Newton <[email-masked]>
Date: Fri, 30 Jun 2006 09:43:53 -0400

On Jun 29, 2006, at 6:29 PM, Rohan Mahy wrote:

> To be clear, I do not have a strong feeling about what does on  
> Brian's list or not.  I think LLDP-MED is a completely reasonable  
> thing for a wired phone vendor to implement on enterprise class  
> phones.

Just throwing in my $0.0199997, I have not formed a strong opinion  
about this either.  It does seem reasonable for enterprise class  
devices with ethernet jacks to implement LLPD-MED, or for devices of  
category Y to implement method X... as what must be implemented by  
the device will always be dictated by the network media it uses.

Where this gets a little tricky is that if there is no one common  
method, then devices may end up implementing things that are not  
appropriate in an attempt to have devices that work in multiple  
network environments... and even then they may end up missing the  
mark.  Therefore, one method that does work in all environments must  
be implemented.   And that is likely to be the L7-LCP.

-andy