ecrit B. Rosen
Internet-Draft Neustar
Intended status: Standards Track November 04, 2013
Expires: May 08, 2014
Validation of Locations Around a Planned Change
draft-rosen-ecrit-lost-planned-changes-00
Abstract
This document defines an extension to LoST (RFC5222) that allows a
planned change to the data in the LoST server to occur. Records that
previously were valid will become invalid at a date in the future,
and new locations will become valid after the date. The extension
adds two elements to the <findservice> request: a URI to be used to
inform the LIS that previously valid locations will be invalid after
the planned change date, and add a date which requests the server to
perform validation as of the date specified.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
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This Internet-Draft will expire on May 08, 2014.
Copyright Notice
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document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions used in this document . . . . . . . . . . . . . . 3
3. <plannedChange> element . . . . . . . . . . . . . . . . . . . 3
4. <locationInvalidated> object . . . . . . . . . . . . . . . . 4
5. Relax NG Schema . . . . . . . . . . . . . . . . . . . . . . . 4
6. Security Considerations . . . . . . . . . . . . . . . . . . . 6
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
7.1. Relax NG Schema Registration . . . . . . . . . . . . . . 6
7.2. LoST Namespace Registration . . . . . . . . . . . . . . . 7
8. Normative References . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
This document describes an update to the LoST protocol [RFC5222]
which allows a <findservice> request to add a URI and a date to be
used with planned changes to the underlying location information in
the server which is used by the validation function. The URI is
retained by the LoST server, associated with the data record that was
validated, and used to notify the LIS (the LoST client) when a
location which was previously valid will become invalid. The date is
used by the client to ask the server to perform validation as of a
future date.
Validation of civic locations involves dealing with data that changes
over time. A typical example is a portion of a county or province
that was not part of a municipality is "annexed" to a municipality.
Prior to the change, the content of the PIDF A3 element would be
blank, or represent some other value and after the change would be
the municipality that annexed that part of the county/province. This
kind of annexation has an effectivity date (typically 00:00 on some
date).
Records in a LIS must change around these kinds of events. The old
record must be discarded, and a new, validated record must be loaded
into the LIS. It is often difficult for the LIS operator to know
that records must be changed. There are other circumstances where
locations that were previously valid become invalid. As RFC5222
defines validation, the only way for a LIS to discover such changes
was to periodically revalidate its entire database. Of course, this
would not facilitate timely changes, and also adds significant load
to the LoST server.
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This extension allows the client to provide a stable URI that is
retained by the server associated with the location provided that the
location information in the request was valid. In the event of a
planned change, or any other circumstance where the LI becomes
invalid, the server sends a notification to the URI informing it of a
change. The notification contains the date and time when the LI
becomes invalid.
Ideally, the LIS will prepare a new record, to be inserted in its
active database, that becomes valid at the precise planned event date
and time, at which point it would also delete the old record.
However, the new record has to be valid, and the LIS would like to
validate it prior to the planned change event. If it requests
validation before the planned event, the server (without this
extension) would inform the client that the location was invalid.
This extension includes an optional "asOf" date and time in the
request that allows the LoST server to provide validation as of the
date and time specified, as opposed to the "as of now" implied in the
current LoST protocol.
2. Conventions used in this document
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].
"Server" in this document refers to the LoST server and "Client" is
the LoST client, even when the server is performing an operation on
the client.
3. <plannedChange> element
This document defines a new element to <findService> called
'plannedChange'. This element contains two attributes: 'uri' and
'asOf'. The 'uri' attribute MUST be a URI with a scheme of https.
The URI will be stored by the server against the location in the
request for subsequent use with the notification function defined
below. To minimize storage requirements of at the server, the length
of the URI MUST be less than 256 bytes. Each client of the server
may only store one URI against a location, where "location" is
defined by policy at the server, since a given unique location may
have many combinations of LI elements that resolve to the same
location. If the server receives a 'uri' for the same location from
the same client, the URI in the request replaces the URI it
previously retained. Policy at the server may limit how many uris it
retains for a given location. A new warning is defined below to be
used to indicate that the URI has not been stored.
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4. <locationInvalidated> object
When the server needs to invalidate a location where the client
provided a URI in <plannedChange>, the server sends
<locationInvalidated> to the URI previously provided. This is the
notice from the server to the client that the location may be invalid
and should be revalidated. <locationInvalidated> contains an asOf
attribute that specifies when the location may become invalid. If
the date/time in asOf is earlier than the time the
<locationInvalidated> was sent, the location may already be invalid
and the LIS should take immediate action.
5. Relax NG Schema
The Relax NG schema in [RFC5222] is modified to be:
namespace a = "http://relaxng.org/ns/compatibility/annotations/1.0"
default namespace ns1 = "urn:ietf:params:xml:ns:lost-plannedChange1"
##
## Extension to Location-to-Service Translation (LoST) Protocol
## to support a planned change to location data
##
## plannedChange is used in the extensionPoint of
## commonRequestPattern in a findService request
##
## locationInvalidated is used by the LoST server to notify a
## LIS that a previously valid location may be (or will become)
## invalid
##
## uriNotStored is a new warning to be used in a
## exceptionContainer in the warnings element of a
## findServiceResponse
##
start =
plannedChange
| locationInvalidated
| uriNotStored
##
## plannedChange
##
div {
plannedChange =
element plannedChange {
attribute uri {
xsd:anyURI }?,
attribute asOf {
xsd:dateTime }?,
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extensionPoint+
}
}
##
## locationInvalidated
##
div {
locationInvalidated =
element locationInvalidated {
attribute asOf {
xsd:dateTime }?,
extensionPoint+
}
}
##
## uriNotStored
##
div {
uriNotStored =
element uriNotStored { basicException }
}
##
## Patterns for inclusion of elements from schemas in
## other namespaces.
##
div {
##
## Any element not in the LoST namespace.
##
notLostChange = element * - (ns1:* | ns1:*) { anyElement }
##
## A wildcard pattern for including any element
## from any other namespace.
##
anyElement =
(element * { anyElement }
| attribute * { text }
| text)*
##
## A point where future extensions
## (elements from other namespaces)
## can be added.
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##
extensionPoint = notLostChanged*
}
6. Security Considerations
As an extension to LoST, this document inherits the security issues
raised in [RFC5222]. The server could be tricked into storing a
malicious URI which, when sent the locationInvalidated object could
trigger something untoward. The server MUST NOT accept any data from
the client in response to POSTing the locationInvalidated.
The server is subject to abuse by clients because it is being asked
to store something and may need to send data to an uncontrolled URI.
Clients could request many URIs for the same location for example.
The server MUST have policy that limits use of this mechanism by a
given client. If the policy is exceeded, the server returns the
uriNotStored warning. The server MUST validate that the content of
the uri sent is syntactically valid and meets the 256 byte limit.
When sending the locationInvalidated object to the uri stored, the
server MUST protect itself against common http vulnerabilities.
The mutual authentication between client and server when is
RECOMMENDED for both the initial findService operation that requests
storing the uri and the sending of the locationInvalidated object.
The server should be well known to the client, and its credential can
be learned in a reliable way. For example, a public safety system
operating the LoST server may have a credential traceable to a well
known Certificate Authority known to provide credentials for public
safety agencies. Many of the clients will be operated by local ISPs
or other service providers where the server operator can reasonably
obtain a good credential to use for the URI. Where the server does
not recognize the client, it's policy MAY limit the use of this
feature beyond what it would limit a client it recognized.
7. IANA Considerations
7.1. Relax NG Schema Registration
URI: urn:ietf:params:xml:schema:lost-planedChange1
Registrant Contact: IETF ECRIT Working Group, Brian Rosen
(br@brianrosen.net).
Relax NG Schema: The Relax NG schema to be registered is contained
in Section 5. Its first line is
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default namespace = "urn:ietf:params:xml:ns:lost-PlannedChange1
and its last line is
}
7.2. LoST Namespace Registration
URI: urn:ietf:params:xml:ns:lost-plannedChange1
Registrant Contact: IETF ECRIT Working Group, Brian Rosen
(br@brianrosen.net).
XML:
BEGIN
<?xml version="2.0"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML Basic 1.0//EN"
"http://www.w3.org/TR/xhtml-basic/xhtml-basic10.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="content-type"
content="text/html;charset=iso-8859-1"/>
<title>LoST Planned Change Namespace</title>
</head>
<body>
<h1>Namespace for LoST Planned Change extension</h1>
<h2>urn:ietf:params:xml:ns:lost-plannedChange1</h2>
<p>See <a href="http://www.rfc-editor.org/rfc/rfc????.txt">
RFC????</a>.</p>
</body>
</html>
END
8. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC5222] Hardie, T., Newton, A., Schulzrinne, H., and H.
Tschofenig, "LoST: A Location-to-Service Translation
Protocol", RFC 5222, August 2008.
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Author's Address
Brian Rosen
Neustar
470 Conrad Dr
Mars, PA 16046
US
EMail: br@brianrosen.net
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