GEOPRIV WG M. Barnes, Ed.
Internet-Draft Nortel
Intended status: Standards Track
Expires: August 29, 2009
February 25, 2009
HTTP Enabled Location Delivery (HELD)
draft-ietf-geopriv-http-location-delivery-13.txt
Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-
Drafts.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
This Internet-Draft will expire on August 29, 2009.
Copyright Notice
Copyright (c) 2009 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents in effect on the date of
publication of this document (http://trustee.ietf.org/license-info).
Please review these documents carefully, as they describe your rights
and restrictions with respect to this document.
Abstract
A Layer 7 Location Configuration Protocol (L7 LCP) is described that
Barnes, et al. Expires August 29, 2009 [Page 1]
Internet-Draft HELD February 2009
is used for retrieving location information from a server within an
access network. The protocol includes options for retrieving
location information in two forms: by value and by reference. The
protocol is an extensible application-layer protocol that is
independent of session-layer. This document describes the use of
HyperText Transfer Protocol (HTTP) and HTTP over Transport Layer
Security (HTTP/TLS) as transports for the protocol.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Conventions & Terminology . . . . . . . . . . . . . . . . . . 4
3. Overview and Scope . . . . . . . . . . . . . . . . . . . . . . 5
4. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 6
4.1. Device Identifiers, NAT and VPNs . . . . . . . . . . . . . 7
4.1.1. Devices and VPNs . . . . . . . . . . . . . . . . . . . 7
4.1.2. LIS Handling of NATs and VPNs . . . . . . . . . . . . 8
4.2. Location by Value . . . . . . . . . . . . . . . . . . . . 8
4.3. Location by Reference . . . . . . . . . . . . . . . . . . 9
5. Protocol Description . . . . . . . . . . . . . . . . . . . . . 9
5.1. Delivery Protocol . . . . . . . . . . . . . . . . . . . . 10
5.2. Location Request . . . . . . . . . . . . . . . . . . . . . 10
5.3. Location Response . . . . . . . . . . . . . . . . . . . . 10
5.4. Indicating Errors . . . . . . . . . . . . . . . . . . . . 11
6. Protocol Parameters . . . . . . . . . . . . . . . . . . . . . 11
6.1. "responseTime" Parameter . . . . . . . . . . . . . . . . . 12
6.2. "locationType" Parameter . . . . . . . . . . . . . . . . . 12
6.2.1. "exact" Attribute . . . . . . . . . . . . . . . . . . 14
6.3. "code" Parameter . . . . . . . . . . . . . . . . . . . . . 14
6.4. "message" Parameter . . . . . . . . . . . . . . . . . . . 15
6.5. "locationUriSet" Parameter . . . . . . . . . . . . . . . . 15
6.5.1. "locationURI" Parameter . . . . . . . . . . . . . . . 15
6.5.2. "expires" Parameter . . . . . . . . . . . . . . . . . 16
6.6. "Presence" Parameter (PIDF-LO) . . . . . . . . . . . . . . 16
7. XML Schema . . . . . . . . . . . . . . . . . . . . . . . . . . 17
8. HTTP Binding . . . . . . . . . . . . . . . . . . . . . . . . . 21
9. Security Considerations . . . . . . . . . . . . . . . . . . . 22
9.1. Assuring that the proper LIS has been contacted . . . . . 23
9.2. Protecting responses from modification . . . . . . . . . . 24
9.3. Privacy and Confidentiality . . . . . . . . . . . . . . . 24
10. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
10.1. HTTPS Example Messages . . . . . . . . . . . . . . . . . . 25
10.2. Simple Location Request Example . . . . . . . . . . . . . 27
10.3. Location Request Example for Multiple Location Types . . . 28
11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 29
11.1. URN Sub-Namespace Registration for
urn:ietf:params:xml:ns:geopriv:held . . . . . . . . . . . 29
Barnes, et al. Expires August 29, 2009 [Page 2]
Internet-Draft HELD February 2009
11.2. XML Schema Registration . . . . . . . . . . . . . . . . . 30
11.3. MIME Media Type Registration for 'application/held+xml' . 30
11.4. Error code Registry . . . . . . . . . . . . . . . . . . . 31
12. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 32
13. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 32
14. Changes since last Version . . . . . . . . . . . . . . . . . . 33
15. References . . . . . . . . . . . . . . . . . . . . . . . . . . 39
15.1. Normative References . . . . . . . . . . . . . . . . . . . 39
15.2. Informative References . . . . . . . . . . . . . . . . . . 40
Appendix A. HELD Compliance to IETF LCP requirements . . . . . . 41
A.1. L7-1: Identifier Choice . . . . . . . . . . . . . . . . . 41
A.2. L7-2: Mobility Support . . . . . . . . . . . . . . . . . . 42
A.3. L7-3: ASP and Access Network Provider Relationship . . . . 42
A.4. L7-4: Layer 2 and Layer 3 Provider Relationship . . . . . 42
A.5. L7-5: Legacy Device Considerations . . . . . . . . . . . . 43
A.6. L7-6: VPN Awareness . . . . . . . . . . . . . . . . . . . 43
A.7. L7-7: Network Access Authentication . . . . . . . . . . . 44
A.8. L7-8: Network Topology Unawareness . . . . . . . . . . . . 44
A.9. L7-9: Discovery Mechanism . . . . . . . . . . . . . . . . 44
A.10. L7-10: PIDF-LO Creation . . . . . . . . . . . . . . . . . 44
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 45
Barnes, et al. Expires August 29, 2009 [Page 3]
Internet-Draft HELD February 2009
1. Introduction
The location of a Device is information that is useful for a number
of applications. The L7 Location Configuration Protocol (LCP)
problem statement and requirements document
[I-D.ietf-geopriv-l7-lcp-ps] provides some scenarios in which a
Device might rely on its access network to provide location
information. The Location Information Server (LIS) service applies
to access networks employing both wired technology (e.g. DSL, Cable)
and wireless technology (e.g. WiMAX) with varying degrees of Device
mobility. This document describes a protocol that can be used to
acquire Location Information (LI) from a LIS within an access
network.
This specification identifies two types of location information that
may be retrieved from the LIS. Location may be retrieved from the
LIS by value, that is, the Device may acquire a literal location
object describing the location of the Device. The Device may also
request that the LIS provide a location reference in the form of a
location URI or set of location URIs, allowing the Device to
distribute its LI by reference. Both of these methods can be
provided concurrently from the same LIS to accommodate application
requirements for different types of location information.
This specification defines an extensible XML-based protocol that
enables the retrieval of LI from a LIS by a Device. This protocol
can be bound to any session-layer protocol, particularly those
capable of MIME transport. This document describes the use of
HyperText Transfer Protocol (HTTP) and HTTP over Transport Layer
Security (HTTP/TLS) as transports for the protocol.
2. Conventions & Terminology
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 [RFC2119].
This document uses the terms (and their acronym forms) Access
Provider (AP), Location Information (LI), Location Object (LO),
Device, Target, Location Generator (LG), Location Recipient (LR),
Rule Maker (RM) and Rule Holder (RH) as defined in RFC 3693, GEOPRIV
Requirements [RFC3693] . The terms Location Information Server
(LIS), Access Network, Access Provider (AP) and Access Network
Provider are used in the same context as defined in the L7 LCP
Problem statement and Requirements document
[I-D.ietf-geopriv-l7-lcp-ps]. The usage of the terms, Civic
Location/Address and Geodetic Location follows the usage in many of
Barnes, et al. Expires August 29, 2009 [Page 4]
Internet-Draft HELD February 2009
the referenced documents.
In describing the protocol, the terms "attribute" and "element" are
used according to their context in XML. The term "parameter" is used
in a more general protocol context and can refer to either an XML
"attribute" or "element".
3. Overview and Scope
This document describes an interface between a Device and a Location
Information Server (LIS). This document assumes that the LIS is
present within the same administrative domain as the Device (e.g.,
the access network). An Access Provider (AP) operates the LIS so
that Devices (and Targets) can retrieve their LI. The LIS exists
because not all Devices are capable of determining LI, and because,
even if a device is able to determine its own LI, it may be more
efficient with assistance. This document does not specify how LI is
determined.
This document is based on the attribution of the LI to a Device and
not specifically a person (end user) or Target, based on the premise
that location determination technologies are generally designed to
locate a device and not a person. It is expected that, for most
applications, LI for the device can be used as an adequate substitute
for the end user's LI. Since revealing the location of the device
almost invariably reveals some information about the location of the
user of the device, the same level of privacy protection demanded by
a user is required for the device. This approach may require either
some additional assurances about the link between device and target,
or an acceptance of the limitation that unless the device requires
active user authentication, there is no guarantee that any particular
individual is using the device at that instant.
Barnes, et al. Expires August 29, 2009 [Page 5]
Internet-Draft HELD February 2009
The following diagram shows the logical configuration of some of the
functional elements identified in [RFC3693] and the LIS defined in
[I-D.ietf-geopriv-l7-lcp-ps] and where this protocol applies, with
the Rule Maker and Target represented by the role of the Device.
Note that only the interfaces relevant to the Device are identified
in the diagram.
+---------------------------------------------+
| Access Network Provider |
| |
| +--------------------------------------+ |
| | Location Information Server | |
| | | |
| | | |
| | | |
| | | |
| +------|-------------------------------+ |
+----------|----------------------------------+
|
|
HELD
|
Rule Maker - _ +-----------+ +-----------+
o - - | Device | | Location |
This document (RFC xxxx) defines HELD messages.
Barnes, et al. Expires August 29, 2009 [Page 17]
Internet-Draft HELD February 2009
Barnes, et al. Expires August 29, 2009 [Page 18]
Internet-Draft HELD February 2009
Barnes, et al. Expires August 29, 2009 [Page 19]
Internet-Draft HELD February 2009
Barnes, et al. Expires August 29, 2009 [Page 20]
Internet-Draft HELD February 2009
8. HTTP Binding
This section describes the use of HTTP [RFC2616] and HTTP Over TLS
[RFC2818] as transport mechanisms for the HELD protocol, which a
conforming LIS and Device MUST support.
Although HELD uses HTTP as a transport, it uses a strict subset of
HTTP features, and due to the restrictions of some features, a LIS is
not a fully compliant HTTP server. It is intended that a LIS can
easily be built using an HTTP server with extensibility mechanisms,
and that a HELD Device can trivially use existing HTTP libraries.
This subset of requirements helps implementors avoid ambiguity with
the many options the full HTTP protocol offers. The LIS MUST NOT
rely on device support for cookies [RFC2965] or use Basic or Digest
authentication [RFC2617].
A HELD request is carried in the body of an HTTP POST request. The
Device MUST include a Host header in the request.
The MIME type of HELD request and response bodies is
"application/held+xml". LIS and Device MUST provide this value in
the HTTP Content-Type and Accept header fields.If the LIS does not
receive the appropriate Content-Type and Accept header fields, the
LIS SHOULD fail the request, returning a 406 (not acceptable)
response. HELD responses SHOULD include a Content-Length header.
Devices MUST NOT use the "Expect" header or the "Range" header in
HELD requests. The LIS MAY return 501 (not implemented) errors if
either of these HTTP features are used. In the case that the LIS
receives a request from the Device containing a If-* (conditional)
header, the LIS SHOULD return a 412 (precondition failed) response.
The POST method is the only method REQUIRED for HELD. If a LIS
chooses to support GET or HEAD, it SHOULD consider the kind of
application doing the GET. Since a HELD Device only uses a POST
method, the GET or HEAD MUST be either an escaped URL (e.g., somebody
found a URL in protocol traces or log files and fed it into their
browser) or somebody doing testing/ debugging. The LIS could provide
information in the HELD response indicating that the URL corresponds
to a LIS server and only responds to HELD POST requests or the LIS
could instead try to avoid any leak of information by returning a
very generic HTTP error message such as 404 (not found).
The LIS populates the HTTP headers of responses so that they are
consistent with the contents of the message. In particular, the
"CacheControl" header SHOULD be set to disable caching of any PIDF-LO
document or Location URIs by HTTP intermediaries. Otherwise, there
is the risk of stale locations and/or the unauthorized disclosure of
Barnes, et al. Expires August 29, 2009 [Page 21]
Internet-Draft HELD February 2009
the LI. This also allows the LIS to control any caching with the
HELD "expires" parameter. The HTTP status code MUST indicate a 2xx
series response for all HELD locationResponse and HELD error
messages.
The LIS MAY redirect a HELD request. A Device MUST handle redirects,
by using the Location header provided by the server in a 3xx
response. When redirecting, the Device MUST observe the delay
indicated by the Retry-After header. The Device MUST authenticate
the server that returns the redirect response before following the
redirect. A Device SHOULD authenticate the LIS indicated in a
redirect.
The LIS SHOULD support persistent connections and request pipelining.
If pipelining is not supported, the LIS MUST NOT allow persistent
connections. The Device MUST support termination of a response by
the closing of a connection.
The use of HTTP also includes a default behaviour, which is triggered
by a POST with no request body. If either of these queries are
received, the LIS MUST attempt to provide either a PIDF-LO document
or a Location URI, as if the request was a location request.
Implementations of HELD that implement HTTP transport MUST implement
transport over TLS [RFC2818]. TLS provides message integrity and
confidentiality between Device and LIS. The Device MUST implement
the server authentication method described in HTTPS [RFC2818]. The
device uses the URI obtained during LIS discovery to authenticate the
server. The details of this authentication method are provided in
section 3.1 of HTTPS [RFC2818]. When TLS is used, the Device SHOULD
fail a request if server authentication fails, except in the event of
an emergency.
9. Security Considerations
HELD is a location acquisition protocol whereby the a client requests
its location from a LIS. Specific requirements and security
considerations for location acquisition protocols are provided in
[I-D.ietf-geopriv-l7-lcp-ps]. An in-depth discussion of the security
considerations applicable to the use of Location URIs and by
reference provision of LI is included in
[I-D.ietf-geopriv-lbyr-requirements].
By using the HELD protocol, the client and the LIS expose themselves
to two types of risk:
Barnes, et al. Expires August 29, 2009 [Page 22]
Internet-Draft HELD February 2009
Accuracy: Client receives incorrect location information
Privacy: An unauthorized entity receives location information
The provision of an accurate and privacy/confidentiality protected
location to the requestor depends on the success of five steps:
1. The client must determine the proper LIS.
2. The client must connect to the proper LIS.
3. The LIS must be able to identify the device by its identifier
(IP Address).
4. The LIS must be able to return the desired location.
5. HELD messages must be transmitted unmodified between the LIS
and the client.
Of these, only the second, third and the fifth are within the scope
of this document. The first step is based on either manual
configuration or on the LIS discovery defined in
[I-D.ietf-geopriv-lis-discovery], in which appropriate security
considerations are already discussed. The fourth step is dependent
on the specific positioning capabilities of the LIS, and is thus
outside the scope of this document.
9.1. Assuring that the proper LIS has been contacted
This document assumes that the LIS to be contacted is identified
either by an IP address or a domain name, as is the case for a LIS
discovered as described in LIS Discovery
[I-D.ietf-geopriv-lis-discovery]. When the HELD transaction is
conducted using TLS [RFC5246], the LIS can authenticate its identity,
either as a domain name or as an IP address, to the client by
presenting a certificate containing that identifier as a
subjectAltName (i.e., as an iPAddress or dNSName, respectively). In
the case of the HTTP binding described above, this is exactly the
authentication described by TLS [RFC2818]. If the client has
external information as to the expected identity or credentials of
the proper LIS (e.g., a certificate fingerprint), these checks MAY be
omitted. Any binding of HELD MUST be capable of being transacted
over TLS so that the client can request the above authentication, and
a LIS implementation for a binding MUST include this feature. Note
that in order for the presented certificate to be valid at the
client, the client must be able to validate the certificate. In
particular, the validation path of the certificate must end in one of
the client's trust anchors, even if that trust anchor is the LIS
certificate itself.
Barnes, et al. Expires August 29, 2009 [Page 23]
Internet-Draft HELD February 2009
9.2. Protecting responses from modification
In order to prevent that response from being modified en route,
messages must be transmitted over an integrity-protected channel.
When the transaction is being conducted over TLS (a required feature
per Section 9.1), the channel will be integrity protected by
appropriate ciphersuites. When TLS is not used, this protection will
vary depending on the binding; in most cases, without protection from
TLS, the response will not be protected from modification en route.
9.3. Privacy and Confidentiality
Location information returned by the LIS must be protected from
access by unauthorized parties, whether those parties request the
location from the LIS or intercept it en route. As in Section 9.2,
transactions conducted over TLS with appropriate ciphersuites are
protected from access by unauthorized parties en route. Conversely,
in most cases, when not conducted over TLS, the response will be
accessible while en route from the LIS to the requestor.
Because HELD is an LCP and identifies clients and targets by IP
addresses, a requestor is authorized to access location for an IP
address only if it is the holder of that IP address. The LIS MUST
verify that the client is the target of the returned location, i.e.,
the LIS MUST NOT provide location to other entities than the target.
Note that this is a necessary, but not sufficient criterion for
authorization. A LIS MAY deny requests according to any local
policy.
A prerequisite for meeting this requirement is that the LIS must have
some assurance of the identity of the client. Since the target of
the returned location is identified by an IP address, simply sending
the response to this IP address will provide sufficient assurance in
many cases. This is the default mechanism in HELD for assuring that
location is given only to authorized clients; LIS implementations
MUST support a mode of operation in which this is the only client
authentication.
Using IP return routability as an authenticator means that location
information is vulnerable to exposure through IP address spoofing
attacks. A temporary spoofing of IP address could mean that a device
could request a Location Object or Location URI that would result in
another Device's location. In addition, in cases where a Device
drops off the network for various reasons, the re-use of the Device's
IP address could result in another Device receiving the original
Device's location rather than its own location. These exposures are
limited by the following:
Barnes, et al. Expires August 29, 2009 [Page 24]
Internet-Draft HELD February 2009
o Location URIs MUST have a limited lifetime, as reflected by the
value for the expires element in Section 6.5.2. The lifetime of
location URIs necessarily depends on the nature of the access.
o The LIS and network SHOULD be configured so that the LIS is made
aware of Device movement within the network and addressing
changes. If the LIS detects a change in the network that results
in it no longer being able to determine the location of the
Device, then all location URIs for that Device SHOULD be
invalidated.
The above measures are dependent on network configuration, which
SHOULD be considered. For instance, in a fixed internet access,
providers may be able to restrict the allocation of IP addresses to a
single physical line, ensuring that spoofing is not possible; in such
an environment, additional measures may not be necessary.
10. Examples
The following sections provide basic HTTP/HTTPS examples, a simple
location request example and a location request for multiple location
types example along with the relevant location responses. To focus
on important portions of messages, the examples in Section 10.2 and
Section 10.3 do not show HTTP/HTTPS headers or the XML prologue. In
addition, sections of XML not relevant to the example are replaced
with comments.
10.1. HTTPS Example Messages
The examples in this section show complete HTTP/HTTPS messages that
include the HELD request or response document.
This example shows the most basic request for a LO. The POST
includes an empty "locationRequest" element.
POST /location HTTP/1.1
Host: lis.example.com:49152
Content-Type: application/held+xml
Content-Length: 87
Barnes, et al. Expires August 29, 2009 [Page 25]
Internet-Draft HELD February 2009
Since the above request does not include a "locationType" element,
the successful response to the request may contain any type of
location. The following shows a response containing a minimal
PIDF-LO.
HTTP/1.1 200 OK
Server: Example LIS
Date: Tue, 10 Jan 2006 03:42:29 GMT
Expires: Tue, 10 Jan 2006 03:42:29 GMT
Cache-control: private
Content-Type: application/held+xml
Content-Length: 594
-34.407 150.88001
2006-01-11T03:42:28+00:00
Wiremap
2006-01-10T03:42:28+00:00
Barnes, et al. Expires August 29, 2009 [Page 26]
Internet-Draft HELD February 2009
The error response to the request is an error document. The
following response shows an example error response.
HTTP/1.1 200 OK
Server: Example LIS
Expires: Tue, 10 Jan 2006 03:49:20 GMT
Cache-control: private
Content-Type: application/held+xml
Content-Length: 135
10.2. Simple Location Request Example
The location request shown below doesn't specify any location types
or response time.
The example response to this location request contains a list of
Location URIs.
https://ls.example.com:9768/357yc6s64ceyoiuy5ax3o
sip:9769+357yc6s64ceyoiuy5ax3o@ls.example.com
Barnes, et al. Expires August 29, 2009 [Page 27]
Internet-Draft HELD February 2009
An error response to this location request is shown below:
10.3. Location Request Example for Multiple Location Types
The following Location Request message includes a request for
geodetic, civic and any Location URIs.
geodetic
civic
locationURI
The corresponding Location Response message includes the requested
location information, including two location URIs.
https://ls.example.com:9768/357yc6s64ceyoiuy5ax3o
sip:9769+357yc6s64ceyoiuy5ax3o@ls.example.com:
-34.407242 150.882518
30
Barnes, et al. Expires August 29, 2009 [Page 28]
Internet-Draft HELD February 2009
AU
NSW
Wollongong
Gwynneville
Northfield Avenue
University of Wollongong
2
Andrew Corporation
2500
39
WS-183
U40
false
2007-05-25T12:35:02+10:00
Wiremap
2007-05-24T12:35:02+10:00
11. IANA Considerations
This document requires several IANA registrations detailed in the
following sections.
11.1. URN Sub-Namespace Registration for
urn:ietf:params:xml:ns:geopriv:held
This section registers a new XML namespace,
"urn:ietf:params:xml:ns:geopriv:held", per the guidelines in
[RFC3688].
URI: urn:ietf:params:xml:ns:geopriv:held
Barnes, et al. Expires August 29, 2009 [Page 29]
Internet-Draft HELD February 2009
Registrant Contact: IETF, GEOPRIV working group,
(geopriv@ietf.org), Mary Barnes (mary.barnes@nortel.com).
XML:
BEGIN
HELD Messages
Namespace for HELD Messages
urn:ietf:params:xml:ns:geopriv:held
[NOTE TO IANA/RFC-EDITOR: Please replace XXXX
with the RFC number for this specification.]
See RFCXXXX
END
11.2. XML Schema Registration
This section registers an XML schema as per the guidelines in
[RFC3688].
URI: urn:ietf:params:xml:schema:geopriv:held
Registrant Contact: IETF, GEOPRIV working group, (geopriv@ietf.org),
Mary Barnes (mary.barnes@nortel.com).
Schema: The XML for this schema can be found as the entirety of
Section 7 of this document.
11.3. MIME Media Type Registration for 'application/held+xml'
This section registers the "application/held+xml" MIME type.
To: ietf-types@iana.org
Subject: Registration of MIME media type application/held+xml
MIME media type name: application
MIME subtype name: held+xml
Required parameters: (none)
Optional parameters: charset
Indicates the character encoding of enclosed XML. Default is
UTF-8.
Barnes, et al. Expires August 29, 2009 [Page 30]
Internet-Draft HELD February 2009
Encoding considerations: Uses XML, which can employ 8-bit
characters, depending on the character encoding used. See RFC
3023 [RFC3023], section 3.2.
Security considerations: This content type is designed to carry
protocol data related to the location of an entity, which could
include information that is considered private. Appropriate
precautions should be taken to limit disclosure of this
information.
Interoperability considerations: This content type provides a basis
for a protocol
Published specification: RFC XXXX [NOTE TO IANA/RFC-EDITOR: Please
replace XXXX with the RFC number for this specification.]
Applications which use this media type: Location information
providers and consumers.
Additional Information: Magic Number(s): (none)
File extension(s): .xml
Macintosh File Type Code(s): (none)
Person & email address to contact for further information: Mary
Barnes
Intended usage: LIMITED USE
Author/Change controller: The IETF
Other information: This media type is a specialization of
application/xml [RFC3023], and many of the considerations
described there also apply to application/held+xml.
11.4. Error code Registry
This document requests that the IANA create a new registry for the
HELD protocol including an initial registry for error codes. The
error codes are included in HELD error messages as described in
Section 6.3 and defined in the schema in the 'codeType' token in the
XML schema in (Section 7)
The following summarizes the requested registry:
Related Registry: Geopriv HELD Registries, Error codes for HELD
Defining RFC: RFC XXXX [NOTE TO IANA/RFC-EDITOR: Please replace XXXX
with the RFC number for this specification.]
Registration/Assignment Procedures: Following the policies outlined
in [RFC5226], the IANA policy for assigning new values for the
Error codes for HELD shall be Specification Required: values and
their meanings must be documented in an RFC or in some other
permanent and readily available reference, in sufficient detail
that interoperability between independent implementations is
possible.
Barnes, et al. Expires August 29, 2009 [Page 31]
Internet-Draft HELD February 2009
Registrant Contact: IETF, GEOPRIV working group, (geopriv@ietf.org),
Mary Barnes (mary.barnes@nortel.com).
This section pre-registers the following seven initial error codes as
described above in Section 6.3:
requestError: This code indicates that the request was badly formed
in some fashion.
xmlError: This code indicates that the XML content of the request
was either badly formed or invalid.
generalLisError: This code indicates that an unspecified error
occurred at the LIS.
locationUnknown: This code indicates that the LIS could not
determine the location of the Device.
unsupportedMessage: This code indicates that the request was not
supported or understood by the LIS. This error code is used when
a HELD request contains a document element that is not supported
by the receiver.
timeout: This code indicates that the LIS could not satisfy the
request within the time specified in the "responseTime" parameter.
cannotProvideLiType: This code indicates that the LIS was unable to
provide LI of the type or types requested. This code is used when
the "exact" attribute on the "locationType" parameter is set to
"true".
notLocatable: This code indicates that the LIS is unable to locate
the Device, and that the Device MUST NOT make further attempts to
retrieve LI from this LIS. This error code is used to indicate
that the Device is outside the access network served by the LIS;
for instance, the VPN and NAT scenarios discussed in
Section 4.1.2.
12. Contributors
James Winterbottom, Martin Thomson and Barbara Stark are the authors
of the original document, from which this WG document was derived.
Their contact information is included in the Author's address
section. In addition, they also contributed to the WG document,
including the XML schema.
13. Acknowledgements
The author/contributors would like to thank the participants in the
GEOPRIV WG and the following people for their constructive input and
feedback on this document (in alphabetical order): Nadine Abbott,
Eric Arolick, Richard Barnes (in particular the security section),
Peter Blatherwick, Ben Campbell, Guy Caron, Eddy Corbett, Martin
Barnes, et al. Expires August 29, 2009 [Page 32]
Internet-Draft HELD February 2009
Dawson, Lisa Dusseault, Jerome Grenier, Ted Hardie, Cullen Jennings,
Neil Justusson, Tat Lam, Marc Linsner, Patti McCalmont, Roger
Marshall, Perry Prozeniuk, Carl Reed, Julian Reschke, Eric Rescorla,
Brian Rosen, John Schnizlein, Shida Schubert, Henning Schulzrinne, Ed
Shrum, Doug Stuard, Hannes Tschofenig and Karl Heinz Wolf.
14. Changes since last Version
NOTE TO THE RFC-Editor: Please remove this section prior to
publication as an RFC.
Changes from WG 12 to 13 (Post-2nd WGLC):
1) Fixed editorial error in section 6.2 with regards to empty
"locationType" - error was introduced in 06 to 07 changes.
2) Added additional text in section 6.5.1 to improve security
associated with locationURIs.
3) Modified XML schema for errorType and responseType to allow an
attribute to be returned. Also, added extensibility to errorType.
Changes from WG 11 to 12 (Post-2nd WGLC):
1) Expanded text in section 8 (HTTP binding) to provide more detail
about the requirements for an HTTP implementation supporting HELD.
Clarified the mandatory functionality and specific handling of other
functionality of HTTP.
2) Clarification in section 9.1 for clients that have external info
wrt the identity or credentials of the LIS.
3) More nits.
Changes from WG 10 to 11 (Post-2nd WGLC):
1) Added additional text around the scope and applicability of the
URI returned from LIS Discovery (section 4).
2) Removed HTTP GET - will always use POST.
3) Removed sentence wrt mobile devices in section 6.2.
4) Added specific recommendation for minimum value for expires in
section 6.5.2 (30 Minutes).
5) Remove reference to RFC 3704 (for IP address spoofing) in section
Barnes, et al. Expires August 29, 2009 [Page 33]
Internet-Draft HELD February 2009
9.3 (bullet 2).
6) Clarified that both HTTP and HTTPS are allowed - changed last
bullet in section 5.1 from REQUIRES to RECOMMENDS.
7) Clarification wrt "presence" parameter in section 6.6 - a "single"
presence parameter may be included.
Changes from WG 09 to 10 (2nd WGLC):
1) Updated text for Devices and VPNs (section 4.1.1) to include
servers such as HTTP and SOCKs, thus changed the text to be generic
in terms of locating LIS before connecting to one of these servers,
etc.
2) Fixed (still buggy) HTTP examples.
3) Added text explaining the whitespaces in XML schema are for
readability/document format limitations and that they should be
handled via parser/schema validation.
4) Miscellaneous editorial nits
Changes from WG 08 to 09 (Post-IETF LC: continued resolution of sec-
dir and gen-art review comments, along with apps-area feedback):
1) Removed heldref/heldrefs URIs, including fixing examples (which
were buggy anyways).
2) Clarified text for locationURI - specifying that the deref
protocol must define or appropriately restrict and clarifying that
requirements for deref must be met and that deref details are out of
scope for this document.
3) Clarified text in security section for support of both HTTP/HTTPS.
4) Changed definition for Location Type to force the specification of
at least one location type.
Changes from WG 07 to 08 (IETF LC: sec-dir and gen-art review
comments):
1) Fix editorial nits: rearranging sections in 4.1 for readibility,
etc.
2) Added back text in Device and VPN section referencing DHCP and
LLDP-MED when a VPN device serves as a LIS.
Barnes, et al. Expires August 29, 2009 [Page 34]
Internet-Draft HELD February 2009
3) Clarified the use of both HTTP and HTTPS.
4) Defined two URIs related to 3 respectively - divided IANA
registrations into sub-sections to accomodate this change. (Note:
LIS Discovery will now define that URI, thus this document defines
the one associatied with a Location reference).
5) Clarified the description of the location URI in Protocol Overview
and Protocol parameter sections. Note that these sections again
reference location dereference protocol for completeness and
clarification of issues that are out of scope for this base document.
6) Defined new error code: notLocatable.
7) Clarifications and corrections in security section.
8) Clarified text for locationType, specifically removing extra text
from "any" description and putting that in a separate paragraph.
Also, provided an example.
9) Added boundaries for "expires" parameter.
10) Clarified that the HELD protocol as defined by this document does
not allow for canceling location references.
Changes from WG 06 to 07 (PROTO review comments):
1) Fix nits: remove unused references, move requirements to
Informational References section, fix long line in ABNF, fix ABNF
(quotes around '?'), add schemaLocation to import namespace in XML
schema.
2) Remove text in Device and VPN section referencing DHCP and LLDP-
MED when a VPN device serves as a LIS, per Issue 1 resolution at
IETF-71. (Editorial oversight in producing version 06).
Changes from WG 05 to 06 (2nd WGLC comments):
1) Updated security section based on WG feedback, including
condensing section 10.1.1 (Assuring the proper LIS has been
contacted), restructuring sections by flattening, adding an
additional step to the list that had been in the Accuracy section and
removing summary section.
2) Changed URI schema to "helds" to address concerns over referential
integrity and for consistency with mandate of TLS for HELD.
3) Editorial clarifications including fixing examples to match HELD
Barnes, et al. Expires August 29, 2009 [Page 35]
Internet-Draft HELD February 2009
URI definition (e.g., adding port, adding randomness to URI examples,
etc.)
4) Updated references removing unused references and moving
requirements docs to Informational Reference section to avoid
downrefs.
Changes from WG 04 to 05 (WGLC comments):
1) Totally replaced the security section with the details provided by
Richard Barnes so that we don't need a reference to the location
security document.
2) Fixed error codes in schema to allow extensibility. Change the
IANA registration to be "specification required".
3) Cleaned up the HELD: URI description, per comments from Martin and
James and partially addressing HELD-04 Issue 1. Put the definition
in a separate section and clarified the applicability (to also
include being a results of the discovery process) and fixed examples.
4) Updated the LocationURI section to be more accurate, address
HELD-04 Issue 3, and include the reference to the new HELD:URI
section. Also, fixed an error in the doc in that the top level parm
in the locationResponse is actually locationUriSet, which contains
any number of locationURI elements and the "expires" parameter. So,
Table 1 was also updated and a new section for the LocationURISet was
added that includes the subsections for the "locationURI" and
"expires". And, then clarified that "expires" applies to
"locationURISet" and not per "locationURI".
5) Editorial nits: pointed out offline by Richard (e.g., by-value ->
by value, by-reference -> by reference, etc.) and onlist by James and
Martin. Please refer to the diff for a complete view of editorial
changes.
6) Added text in HTTP binding section to disable HTTP caching
(HELD-04 Issue 5 on the list).
Changes from WG 03 to 04:
1) Terminology: clarified in terminology section that "attribute" and
"element" are used in the strict XML sense and "parameter" is used as
a general protocol term Replaced term "HTTP delivery" with "HTTP
transport". Still have two terms "HTTP transport" and "HTTP
binding", but those are consistent with general uses of HTTP.
2) Editorial changes and clarifications: per Roger Marshall's and
Barnes, et al. Expires August 29, 2009 [Page 36]
Internet-Draft HELD February 2009
Eric Arolick's comments and subsequent WG mailing list discussion.
3) Changed normative language for describing expected and recommended
LIS behaviors to be non-normative recommendations in cases where the
protocol parameters were not the target of the discussion (e.g., we
can't prescribe to the LIS how it determines location or what it
defines to be an "accurate" location).
4) Clarified responseTime attribute (section 6.1). Changed type from
"decimal" to "nonNegativeInteger" in XML schema (section 7)
5) Updated Table 1 in section 6 to only include top-level parameters
and fixed some errors in that table (i.e., code for locationResponse)
and adding PIDF-LO to the table. Added a detailed section describing
PIDF-LO (section 6.6), moving some of the normative text in the
Protocol Overview to this section.
6) Added schema and description for locationURI to section 6.5.
Added IANA registration for HELD: URI schema.
7) Added IANA registry for error codes.
Changes from WG 02 to 03:
1) Added text to address concern over use of IP address as device
identifier, per long email thread - changes to section 3 (overview)
and section 4 (protocol overview).
2) Removed WSDL (section 8 updated, section 8.1 and 10.4 removed)
3) Added extensibility to baseRequestType in the schema (an oversight
from previous edits), along with fixing some other nits in schema
(section 7)
4) Moved discussion of Location URI from section 5.3 (Location
Response) to where it rightly belonged in Section 6.5 (Location URI
Parameter).
5) Clarified text for "expires" parameter (6.5.1) - it's an optional
parm, but required for LocationURIs
6) Clarified responseTime parameter: when missing, then the LCS
provides most precise LI, with the time required being implementation
specific.
7) Clarified that the MUST use in section 8 (HTTP binding) is a MUST
implement.
Barnes, et al. Expires August 29, 2009 [Page 37]
Internet-Draft HELD February 2009
8) Updated references (removed unused/added new).
Changes from WG 01 to 02:
1) Updated Terminology to be consistent with WG agreements and other
documents (e.g., LCS -> LIS and removed duplicate terms). In the
end, there are no new terms defined in this document.
2) Modified definition of responseTime to reflect WG consensus.
3) Removed jurisdictionalCivic and postalCivic locationTypes (leaving
just "civic").
4) Clarified text that locationType is optional. Fixed table 1 and
text in section 5.2 (locationRequest description). Text in section
6.2 (description of locationType element) already defined the default
to be "any".
5) Simplified error responses. Separated the definition of error
response type from the locationResponse type thus no need for
defining an error code of "success". This simplifies the schema and
processing.
6) Updated schema/examples for the above.
7) Updated Appendix A based on updates to requirements document,
specifically changes to A.1, A.3 and adding A.10.
8) Miscellaneous editorial clarifications.
Changes from WG 00 to 01:
1) heldResponse renamed to locationResponse.
2) Changed namespace references for the PIDF-LO geoShape in the
schema to match the agreed GML PIDF-LO Geometry Shape Application
Schema.
3) Removed "options" element - leaving optionality/extensibility to
XML mechanisms.
4) Changed error codes to be enumerations and not redefinitions of
HTTP response codes.
5) Updated schema/examples for the above and removed some remnants of
the context element.
6) Clarified the definition of "Location Information (LI)" to include
Barnes, et al. Expires August 29, 2009 [Page 38]
Internet-Draft HELD February 2009
a reference to the location (to match the XML schema and provide
consistency of usage throughout the document). Added an additional
statement in section 7.2 (locationType) to clarify that LCS MAY also
return a Location URI.
7) Modifed the definition of "Location Configuration Server (LCS)" to
be consistent with the current definiton in the requirements
document.
8) Updated Location Response (section 6.3) to remove reference to
context and discuss the used of a local identifier or unlinked
pseudonym in providing privacy/security.
9) Clarified that the source IP address in the request is used as the
identifier for the target/device for the HELD protocol as defined in
this document.
10) Miscellaneous editorial clarifications.
15. References
15.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246, August 2008.
[RFC2965] Kristol, D. and L. Montulli, "HTTP State Management
Mechanism", RFC 2965, October 2000.
[RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext
Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.
[RFC2617] Franks, J., Hallam-Baker, P., Hostetler, J., Lawrence, S.,
Leach, P., Luotonen, A., and L. Stewart, "HTTP
Authentication: Basic and Digest Access Authentication",
RFC 2617, June 1999.
[RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
January 2004.
[I-D.ietf-geopriv-pdif-lo-profile]
Barnes, et al. Expires August 29, 2009 [Page 39]
Internet-Draft HELD February 2009
Winterbottom, J., Thomson, M., and H. Tschofenig, "GEOPRIV
PIDF-LO Usage Clarification, Considerations and
Recommendations", draft-ietf-geopriv-pdif-lo-profile-14
(work in progress), November 2008.
[W3C.REC-xmlschema-1-20041028]
Thompson, H., Maloney, M., Beech, D., and N. Mendelsohn,
"XML Schema Part 1: Structures Second Edition", World Wide
Web Consortium Recommendation REC-xmlschema-1-20041028,
October 2004,
.
[W3C.REC-xmlschema-2-20041028]
Biron, P. and A. Malhotra, "XML Schema Part 2: Datatypes
Second Edition", World Wide Web Consortium
Recommendation REC-xmlschema-2-20041028, October 2004,
.
[I-D.ietf-geopriv-lis-discovery]
Thomson, M. and J. Winterbottom, "Discovering the Local
Location Information Server (LIS)",
draft-ietf-geopriv-lis-discovery-07 (work in progress),
February 2009.
15.2. Informative References
[RFC0793] Postel, J., "Transmission Control Protocol", STD 7,
RFC 793, September 1981.
[RFC3023] Murata, M., St. Laurent, S., and D. Kohn, "XML Media
Types", RFC 3023, January 2001.
[RFC3693] Cuellar, J., Morris, J., Mulligan, D., Peterson, J., and
J. Polk, "Geopriv Requirements", RFC 3693, February 2004.
[RFC3825] Polk, J., Schnizlein, J., and M. Linsner, "Dynamic Host
Configuration Protocol Option for Coordinate-based
Location Configuration Information", RFC 3825, July 2004.
[LLDP-MED]
TIA, "ANSI/TIA-1057 Link Layer Discovery Protocol - Media
Endpoint Discovery".
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, January 2005.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
Barnes, et al. Expires August 29, 2009 [Page 40]
Internet-Draft HELD February 2009
IANA Considerations Section in RFCs", BCP 26, RFC 5226,
May 2008.
[I-D.ietf-geopriv-l7-lcp-ps]
Tschofenig, H. and H. Schulzrinne, "GEOPRIV Layer 7
Location Configuration Protocol; Problem Statement and
Requirements", draft-ietf-geopriv-l7-lcp-ps-09 (work in
progress), February 2009.
[I-D.ietf-geopriv-lbyr-requirements]
Marshall, R., "Requirements for a Location-by-Reference
Mechanism", draft-ietf-geopriv-lbyr-requirements-06 (work
in progress), February 2009.
[I-D.ietf-sip-location-conveyance]
Polk, J. and B. Rosen, "Location Conveyance for the
Session Initiation Protocol",
draft-ietf-sip-location-conveyance-12 (work in progress),
November 2008.
[I-D.winterbottom-geopriv-deref-protocol]
Winterbottom, J., Tschofenig, H., Schulzrinne, H.,
Thomson, M., and M. Dawson, "An HTTPS Location
Dereferencing Protocol Using HELD",
draft-winterbottom-geopriv-deref-protocol-03 (work in
progress), February 2009.
Appendix A. HELD Compliance to IETF LCP requirements
This appendix describes HELD's compliance to the requirements
specified in the [I-D.ietf-geopriv-l7-lcp-ps].
A.1. L7-1: Identifier Choice
"The L7 LCP MUST be able to carry different identifiers or MUST
define an identifier that is mandatory to implement. Regarding the
latter aspect, such an identifier is only appropriate if it is from
the same realm as the one for which the location information service
maintains identifier to location mapping."
COMPLY
HELD uses the IP address of the location request message as the
primary source of identity for the requesting device or target. This
identity can be used with other contextual network information to
provide a physical location for the Target for many network
deployments. There may be network deployments where an IP address
Barnes, et al. Expires August 29, 2009 [Page 41]
Internet-Draft HELD February 2009
alone is insufficient to identify a Target in a network. However,
any necessary identity extensions for these networks is beyond the
scope of this document.
A.2. L7-2: Mobility Support
"The GEOPRIV Layer 7 Location Configuration Protocol MUST support a
broad range of mobility from devices that can only move between
reboots, to devices that can change attachment points with the impact
that their IP address is changed, to devices that do not change their
IP address while roaming, to devices that continuously move by being
attached to the same network attachment point."
COMPLY
Mobility support is inherently a characteristic of the access network
technology and HELD is designed to be access network agnostic.
Consequently HELD complies with this requirement. In addition HELD
provides specific support for mobile environments by providing an
optional responseTime attribute in location request messages.
Wireless networks often have several different mechanisms at their
disposal for position determination (e.g. Assisted GPS versus
location based on serving base station identity), each providing
different degrees of accuracy and taking different amounts of time to
yield a result. The responseTime parameter provides the LIS with a
criterion which it can use to select a location determination
technique.
A.3. L7-3: ASP and Access Network Provider Relationship
"The design of the L7 LCP MUST NOT assume a business or trust
relationship between the Application Service Provider (ASP) and the
Access Network Provider. Requirements for resolving a reference to
location information are not discussed in this document."
COMPLY
HELD describes a location acquisition protocol between a Device and a
LIS. In the context of HELD, the LIS is within the Access Network.
Thus, HELD is independent of the business or trust relationship
between the Application Service Provider (ASP) and the Access Network
Provider. Location acquisition using HELD is subject to the
restrictions described in Section 9.
A.4. L7-4: Layer 2 and Layer 3 Provider Relationship
"The design of the GEOPRIV Layer 7 Location Configuration Protocol
MUST assume that there is a trust and business relationship between
Barnes, et al. Expires August 29, 2009 [Page 42]
Internet-Draft HELD February 2009
the L2 and the L3 provider. The L3 provider operates the LIS and
needs to obtain location information from the L2 provider since this
one is closest to the end host. If the L2 and L3 provider for the
same host are different entities, they cooperate for the purposes
needed to determine end system locations."
COMPLY
HELD was specifically designed with this model in mind and readily
allows itself to chaining requests between operators without a change
in protocol being required. HELD is a webservices protocol which can
be bound to transports other than HTTP, such as BEEP. Using a
protocol such as BEEP offers the option of high request throughput
over a dedicated connection between an L3 provider and an L2 provider
without incurring the serial restriction imposed by HTTP. This is
less easy to do with protocols that do not decouple themselves from
the transport.
A.5. L7-5: Legacy Device Considerations
"The design of the GEOPRIV Layer 7 Location Configuration Protocol
MUST consider legacy residential NAT devices and NTEs in an DSL
environment that cannot be upgraded to support additional protocols,
for example to pass additional information through DHCP."
COMPLY
HELD is an application protocol and operates on top of IP. A HELD
request from a host behind a residential NAT will traverse the NAT
acquiring the external address of the home router. The location
provided to the host therefore will be the address of the home router
in this circumstance. No changes are required to the home router in
order to support this function, HELD was designed specifically to
address this deployment scenario.
A.6. L7-6: VPN Awareness
"The design of the GEOPRIV Layer 7 Location Configuration Protocol
MUST assume that at least one end of a VPN is aware of the VPN
functionality. In an enterprise scenario, the enterprise side will
provide the LIS used by the client and can thereby detect whether the
LIS request was initiated through a VPN tunnel."
COMPLY
HELD does not preclude a LIS on the far end of a VPN tunnel being
aware that the client request is occurring over that tunnel. It also
does not preclude a client device from accessing a LIS serving the
Barnes, et al. Expires August 29, 2009 [Page 43]
Internet-Draft HELD February 2009
local physical network and subsequently using the location
information with an application that is accessed over a VPN tunnel.
A.7. L7-7: Network Access Authentication
"The design of the GEOPRIV Layer 7 Location Configuration Protocol
MUST NOT assume prior network access authentication."
COMPLY
HELD makes no assumptions about prior network access authentication.
HELD strongly recommends the use of TLS with server-side certificates
for communication between the end-point and the LIS. There is no
requirement for the end-point to authenticate with the LIS.
A.8. L7-8: Network Topology Unawareness
"The design of the GEOPRIV Layer 7 Location Configuration Protocol
MUST NOT assume end systems being aware of the access network
topology. End systems are, however, able to determine their public
IP address(es) via mechanisms such as STUN or NSIS NATFW NSLP."
COMPLY
HELD makes no assumption about the network topology. HELD doesn't
require that the device know its external IP address, except where
that is required for discovery of the LIS.
A.9. L7-9: Discovery Mechanism
"The L7 LCP MUST define a single mandatory to implement discovery
mechanism."
COMPLY
HELD uses the discovery mechanism in
[I-D.ietf-geopriv-lis-discovery].
A.10. L7-10: PIDF-LO Creation
"When a LIS creates a PIDF-LO per RFC 4119 then it MUST put the
element into the element of the presence document
(see RFC 4479). This ensures that the resulting PIDF-LO document,
which is subsequently distributed to other entities, conforms to the
rules outlined in ". [I-D.ietf-geopriv-pdif-lo-profile]
COMPLY
Barnes, et al. Expires August 29, 2009 [Page 44]
Internet-Draft HELD February 2009
HELD protocol overview (Section 4 ) describes the requirements on the
LIS in creating the PIDF-LO and prescribes that the PIDF-LO generated
by the LIS MUST conform to [I-D.ietf-geopriv-pdif-lo-profile].
Authors' Addresses
Mary Barnes (editor)
Nortel
2201 Lakeside Blvd
Richardson, TX
USA
Email: mary.barnes@nortel.com
James Winterbottom
Andrew
PO Box U40
Wollongong University Campus, NSW 2500
AU
Phone: +61 2 4221 2938
Email: james.winterbottom@andrew.com
URI: http://www.andrew.com/
Martin Thomson
Andrew
PO Box U40
Wollongong University Campus, NSW 2500
AU
Phone: +61 2 4221 2915
Email: martin.thomson@andrew.com
URI: http://www.andrew.com/
Barnes, et al. Expires August 29, 2009 [Page 45]
Internet-Draft HELD February 2009
Barbara Stark
BellSouth
Room 7A43
725 W Peachtree St.
Atlanta, GA 30308
US
Email: barbara.stark@att.com
Barnes, et al. Expires August 29, 2009 [Page 46]