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general RADEXT Working Group Internet-Draft RADIUS 5580 Location This document describes a new location profile for use with the RADIUS Location-Data Attribute. The new profile is used to carry a geospatial location profile that includes location uncertainty.

Introduction The Location-Data Attribute specified in defines the ability to encode a geospatial location format where the geospatial location information is encoded as an opaque object, with the format being based on the Location Configuration Information (LCI) format defined in Section 2 of . has been obsoleted by , where the encoding of the geospatial location format has been enhanced to enable signalling of uncertainty parameters for latitude, longitude and altitude. This specification defines the ability to transport the GeoLocation (GeoLoc) profile defined in in the Location-Data Attribute specified in , enabling location uncertainty values to be signaled. Individual use-cases operating using this location profile may require the location uncertainty is below some threshold value. Details of such use-cases and how a RADIUS Server responds when receiving a Location-Data Attribute with uncertainty that exceeds any defined threshold are out of scope of this document.

Requirements Language The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 when, and only when, they appear in all capitals, as shown here.

Terminology Uncertainty:

• The uncertainty of a location estimate is the distance from the actual location the estimate is likely to fall within. The lower the value the more accurate the estimate.

Confidence:

• An estimated upper bound on the probability that a "true" value is found within the extents defined by the uncertainty.

Geospatial Location With Uncertainty Profile This section defines the geospatial location-information profile corresponding to the value (TBC) indicated in the Code field of the Location-Information Attribute, as specified in . Geospatial location information with uncertainty is encoded as an opaque object. The format is based on the DHCPv4 GeoLoc Option 144, as specified in Section 2.2.2 of , but starts with the third octet (i.e., the code for the DHCP option and the length field is not included). Whereas defines a means for representing uncertainty, it does not specify a corresponding value for the confidence. Following Section 3.4 of , a default value of 95% confidence SHOULD be assumed for the combination of the uncertainty on each axis.

Security Considerations Providing uncertainty information can reveal information about the process by which location information is generated.

IANA Considerations

Updated Location Profiles Registry IANA is requested to allocate the value TBC to signal the encoding of this type in the Code field of the Location-Information Attribute, as specified in , and to update the Location Profiles Registry with the new value: Value (TBC): Geospatial location profile with uncertainty, as described in .

Updated Location-Capable Attribute Registry IANA is requested to allocate the value TBC to add a new entry in the Location-Capable Attribute as specified in : Value (TBC): Capability Token corresponds to GEO_UNCERTAINTY_LOCATION

Updated Requested-Location-Info Attribute Registry IANA is requested to allocate the value TBC to add a new entry in the Requested-Location-Info Attribute as specified in : Value (TBC): Capability Token corresponds to GEO_UNCERTAINTY_LOCATION

In many standards track documents several words are used to signify the requirements in the specification. These words are often capitalized. This document defines these words as they should be interpreted in IETF documents. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements. This document defines key concepts of uncertainty and confidence as they pertain to location information. Methods for the manipulation of location estimates that include uncertainty information are outlined. This document normatively updates the definition of location information representations defined in RFCs 4119 and 5491. It also deprecates related terminology defined in RFC 3693. RFC 2119 specifies common key words that may be used in protocol specifications. This document aims to reduce the ambiguity by clarifying that only UPPERCASE usage of the key words have the defined special meanings. This document describes procedures for conveying access-network ownership and location information based on civic and geospatial location formats in Remote Authentication Dial-In User Service (RADIUS) and Diameter. The distribution of location information is a privacy-sensitive task. Dealing with mechanisms to preserve the user's privacy is important and is addressed in this document. [STANDARDS-TRACK] This document specifies Dynamic Host Configuration Protocol options (both DHCPv4 and DHCPv6) for the coordinate-based geographic location of the client. The Location Configuration Information (LCI) includes Latitude, Longitude, and Altitude, with resolution or uncertainty indicators for each. Separate parameters indicate the reference datum for each of these values. This document obsoletes RFC 3825. [STANDARDS-TRACK] This document specifies a Dynamic Host Configuration Protocol Option for the coordinate-based geographic location of the client. The Location Configuration Information (LCI) includes latitude, longitude, and altitude, with resolution indicators for each. The reference datum for these values is also included. [STANDARDS-TRACK]