Network Working Group D. Stanley
Internet Draft Aruba Networks
Intended status: Proposed Standard S. McCann
Expires: April 19, 2010 Research in Motion
Gabor Bajko
Nokia
Allan Thomson
Cisco Systems
October 19, 2009
Interior Location Extensions
draft-stanley-geopriv-int-ext-00.txt
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Abstract
This document extends the definition of Interior Location defined in
draft-rosen-geopriv-pidf-interior to include a set of registered
elements that allow for the expression of relative location. The
expression of relative location enables LAN technologies that have such
capability to provide a more accurate location description than normally
allowed using [RFC4776] [RFC5139]. By registering the elements
described here, interoperability between applications and vendors is
enabled.
Table of Contents
1. Introduction.......................................................2
1.1. Requirements Notation..........................................3
1.2. Motivation for Interior Location...............................3
2. INT Elements.......................................................4
2.1. Measurement Uncertainty........................................4
2.2. Reference Location.............................................4
3. Shapes.............................................................5
3.1. Point........................................................5
3.2. Circle.......................................................6
3.3 Arcband.......................................................7
3.4. Polygon......................................................9
4. Security Considerations...........................................11
5. IANA Considerations...............................................11
5.1. INT Name Registry.............................................11
6. References........................................................12
6.1. Normative References..........................................12
7. Acknowledgments...................................................12
Authors' Addresses...................................................12
1. Introduction
This extension to the definition of interior locations is a set of
registered elements that provide a common method to express
additional location information in the form of a relative location
from a reference location.
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The relative location information could be produced by LAN
technologies and used in environments such as large campus networks,
large public buildings, hot spots, etc.
Using geodetic coordinates to describe the location of an entity has
limitations that restrict its usability, especially in indoor
environments. In these cases, describing the determined location of
the entity using civic and relative addressing may be both more
feasible and easier for human consumption than using geodetic
coordinates.
1.1. Requirements Notation
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC-2119.
1.2. Motivation for Interior Location
Current civic addressing [RFC4776],[RFC5139] is neither granular nor
accurate enough to be able to describe an arbitrary indoor position
of a network device with precision. This document proposes to extend
civic addressing with a reference point, an offset and relative
location from these points using shapes in the Cartesian coordinate
system to describe the position of a network device. The data
included within the relative position parameters is supplementary to,
not exclusive of the existing civic location data expressed in PIDF-
LO [RFC4119] and the DHCP Civic Location option [RFC4776] [RFC5139].
An example of this may be a 4-story campus building belonging to a
company that has wireless LAN technology deployed throughout the
building. The building has complete RF coverage and the wireless
network architecture for the building can locate network devices
within that building to within a few meters using RF measurements or
other technologies. The supplementary data provided by relative
location would enable a more granular location expression for a
located device. In addition to "34 Some Street, Anytown, PA, USA,
Building 10, Floor 4", a relative position "within X meters of the
point which is 10 meters south and 15 meters east of the main
elevator on Floor 4" is possible.
Another example of this may be a popular wireless hotspot located at
234 N. Main St., Anytown, PA. USA. It is reasonable to expect that
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234 N. Main St. covers a geographic area that encompasses several
hundred square meters. The wireless network architecture for this
hotspot could include several wireless infrastructure access points.
The supplementary data provided via relative location would enable a
more granular location expression. In addition to providing 234 N.
Main St., Anytown, PA. USA, a relative position like "within X meters
from the main entrance" could be added.
2. INT Elements
Included in the interior relative location architecture below is a
set of INT elements and corresponding attributes that are registered
with the namespace to enable interoperability between various vendors
and devices. Included are 4 shapes: point, circle, arcband, and
polygon. Mixing the use of these registered INT elements with any
quantity of local, or private, INT elements is allowed. Please note
that all INT elements are supplementary to Civic location elements in
PIDF-LO. The order in which these new elements appear in PIDF-LO is
significant based on the text for each shape below.
2.1. Measurement Uncertainty
When calculating a network device's location using the technology
described above, there is an area of uncertainty associated with the
measurement techniques. The method of expressing a calculated
position and separately expressing the area of uncertainty has been
debated as to its usefulness. Hence, there is no facility included
here to allow the expression of an area of uncertainty separate from
the shape. It is expected that the expressed shape will include the
area of uncertainty, to yield a result that the device is contained
within the shape to a 95% confidence level.
2.2. Reference Location
Measurement from the reference is provided by using the labels of X,
Y and Z. The east-west dimension is labeled X and north-south
dimension is labeled Y. A positive Y value is considered north of
the reference, a negative Y value south of the reference, a positive
X value for east of the reference and a negative X value indicates
west of the reference. The height value, Z, is optional. A positive
Z value would indicate the height above the floor level at the
reference whereas a negative Z value would indicate a height below
the reference. The absence of a Z value indicates the shape is at
the floor level of the reference or unknown. All position values are
in meters.
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3. Shapes
The different shapes are described by first declaring a mandatory
reference element, which is the starting location for the offset
positions. Next is a mandatory declaration of the shape type, which
includes point, circle, arcband, or polygon. Following the shape
declaration element are the shape specific offset measurement
elements as outlined below.
3.1. Point
The point shape includes the reference, the shape type, and offset
measurement values for X, Y, and optionally Z. See Figure 1.
Front Door
+25
+10
+10 (optional)
+--------------------------------------x
| SHAPE-OFFSET-X
|
|
|
| SHAPE-OFFSET-Y
|
|
REF
Figure 1 - Point Shape
3.1.1 Point Example
An example of a point shape included in the whole of the civic
location elements would be:
US
Florida
Miami
8200
NW
41st
Street
33166
4
400
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Front Door
+25
+10
+10
3.2. Circle
The circle shape includes the reference, shape type, offset
measurement values for the X, Y, and optionally Z of the center point
of the circle, and a radius value. See Figure 2.
Front Door
+34
-9
+5 (optional)
4
REF
|
|
|
|
| SHAPE-OFFSET-Y _,...._
| ,-' `-.
| ,' --,`. RADIUS
| / ,'| \
| .' / '.
| | ,' |
+-----------------------------+---------x |
SHAPE-OFFSET-X \ /
\ /
`. ,'
`. ,'
`--...--'
Figure 2 - Circle Shape
3.2.2. Circle Example
An example of a circle shape included in the whole of the civic
location elements would be:
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US
Florida
Miami
8200
NW st 41
Street
33166
4
400
Front Door
+34
-9
+5
4
3.3 Arcband
The arcband shape includes the reference, shape type, offset
measurement value of the central point, the optional Z value, the
inner and outer radius values, the start angle, and the opening
angle. See Figure 3.
Front Door
+17
-2
+2 (optional)
8
18
329
82
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_,,..,--------....__
'' `--..
\ ``-.
REF \ `-._
| \ `.
| \ ;>
| \ ,'
| \ __......__ ,'
| .-'' `--._ ,'
| \ `. / OuterRadius
| `. `.,'
| SHAPE-OFFSET-Y | Opening ,'
| | Angle ,'
| `. /
| | ,'
| | ,'
| Start `. ,' InnerRadius
| Angle | /
| | ,'
+------------------------------------x
SHAPE-OFFSET-X
Figure 3 - Arcband Shape
3.3.1 Arcband Example
An example of an arcband shape included in the whole of the civic
location elements would be:
US
Florida
Miami
8200
NW
41st
Street
33166
4
400
Front Door
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+17
-2
+2
8
18
329
82
3.4. Polygon
The polygon shape includes the reference, the shape type, the number
of polygon points, the offset measurement value for each point,
optionally a calculated geo center point of the polygon, and the
optional Z value. This example shows a single Z value for the entire
shape. See Figure 4.
Front Door
5
-18
-8
-20
-5
-25
-6
-25
-10
-20
-13
-18
-8
-10 (optional)
-20 (optional)
+10 (optional)
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REF
|
|
|
|
| SHAPE-
| OFFSET-Y(A)
|
|
|
SHAPE-OFFSET-X(A) |
_,.-------------------------------------+ SHAPE-
_,,-' `. | OFFSET-Y(B)
_,.-'' \ SHAPE-OFFSET-X(B) |
'------------------\--------------------------------+
| \ | SHAPE-
| `. | OFFSET-Y(C)
| \ |
| \ SHAPE-OFFSET-X(C) |
| ;--------------------------+ SHAPE-
| ,-' | OFFSET-Y(D)
| ,' SHAPE-OFFSET-X(D) |
':----------------;----------------------------------+
`-. ,' | SHAPE-
`. ,-' | OFFSET-Y(E)
`-. ,' SHAPE-OFFSET-X(E) |
'------------------------------------------+
Figure 4 - Polygon Shape
3.4.1 Polygon Example
An example of a polygon shape included in the whole of the civic
location elements would be:
US
Florida
Miami
8200
NW
41st
Street
33166
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4
400
Front Door
5
-18
-8
-20
-5
-25
-6
-25
-10
-20
-13
-18
-8
-10
-20
4. Security Considerations
The XML representation described in this document is designed for
inclusion in a PIDF-LO document. As such, it is subject to the same
security considerations as are described in [RFC4119]. Considerations
relating to the inclusion of this representation in other XML documents
are outside the scope of this document.
5. IANA Considerations
5.1. INT Name Registry
This document adds new values to the registry managed by IANA called
"INT Names". The new values are listed below:
Reference
Point
Circle
Arcband
Polygon
SHAPE-OFFSET-X
SHAPE-OFFSET-Y
SHAPE-OFFSET-Z
Radius
InnerRadius
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OuterRadius
StartAngle
Opening
PolygonPoints
SHAPE-GEOCENTER-X
SHAPE-GEOCENTER-Y
SHAPE-OFFSET-Z
6. References
6.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4119] Peterson, J., "A Presence-based GEOPRIV Location Object
Format", RFC 4119, December 2005.
[RFC5139] Thomson, M. and J. Winterbottom, "Revised Civic Location
Format for Presence Information Data Format Location
Object (PIDF-LO)", RFC 5139, February 2008.
[RFC4776] H. Schulzrinne, "DHCPv4 and DHCPv6 Option for Civic
Addresses Configuration Information", RFC4776, November
2006.
7. Acknowledgments
The authors would like to acknowledge James Polk and Marc Linsner for
their contributions to this document.
This document was prepared using 2-Word-v2.0.template.dot and "JavE"
from http://www.jave.de without whom those radii would not have been.
Authors' Addresses
Dorothy Stanley
Aruba Networks
1322 Crossman Ave
Sunnyvale, CA 94089 USA
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+1 630-363-1389
Email: dstanley@arubanetworks.com
Stephen McCann
Research in Motion
200 Bath Road
Slough
Berkshire, SL1 3XE, UK
+44 1753 667099
Email: smccann@rim.com
Gabor Bajko
Nokia
323 Fairchild Drive
Mountain View, CA, 94043 USA
Email: gabor.bajko@nokia.com
Allan Thomson
Cisco Systems, Inc.
170 West Tasman Drive
San Jose, California, 95134 USA
Email: althomso@cisco.com
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