| Network Working Group | M. Douglass |
| Internet-Draft | RPI |
| Intended status: Standards Track | C. Daboo |
| Expires: August 06, 2014 | Apple |
| February 02, 2014 |
Timezone Service Protocol
draft-douglass-timezone-service-09
This document defines a timezone service protocol that allows reliable, secure and fast delivery of timezone data to client systems such as calendaring and scheduling applications or operating systems.
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Copyright (c) 2014 IETF Trust and the persons identified as the document authors. All rights reserved.
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Timezone data typically combines a coordinated universal time (UTC) offset with daylight saving time (DST) rules. Timezones are typically tied to specific geographic and geopolitical regions. Whilst the UTC offset for particular regions changes infrequently, DST rules can change frequently and sometimes with very little notice (sometimes hours before a change comes into effect).
Calendaring and scheduling systems, such as those that use iCalendar [RFC5545], as well as operating systems, critically rely on timezone data to determine the correct local time. As such they need to be kept up to date with changes to timezone data. To date there has been no fast and easy way to do that. Timezone data is often supplied in the form of a set of data files that have to be "compiled" into a suitable database format for use by the client application or operating system. In the case of operating systems, often those changes only get propagated to client machines when there is an operating system update, which can be infrequent, resulting in inaccurate timezone data being present for significant amounts of time.
This specification defines a timezone service protocol that allows for fast, reliable and accurate delivery of timezone data to client systems. This protocol is based on HTTP [RFC2616] using a REST style API, with JSON [RFC4627] responses.
This specification does not define the source of the timezone data. It is assumed that a reliable and accurate source is available. One such source is the IANA hosted timezone database [RFC6557].
Discussion of this document should take place on the calsify mailing list calsify@ietf.org
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].
The following terms with the given meanings are used throughout this document.
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(a) | Contributors | | Contributors |
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(b) | Publisher A | | Publisher B |
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(c) | Provider |
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(d) | Provider | | | Provider |
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(e) | Client | | Client | | Client | | Client |
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Figure 1: Timezone Service Architecture
The overall process for the delivery of timezone data can be visualized via the diagram shown below.
The overall service is made up of several layers:
Some of those layers may be coalesced by implementors. For example, a vendor may choose to implement the entire service as a single monolithic virtual server with the address embedded in distributed systems. Others may choose to provide a service consisting of multiple layers of providers, many local servers and a small number of root servers.
This specification is only concerned with the protocol used to exchange data between providers and from provider to client. This specification does not define how contributors pass their information to publishers, nor how those publishers vet that information to obtain trustworthy data, nor the format of the data produced by the publishers.
Timezone identifiers are unique names associated with each timezone, as defined by publishers. The iCalendar [RFC5545] specification has a "TZID" property and parameter whose value is set to the corresponding timezone identifier, and used to identify timezone data and relate timezones to start and end dates in events, etc. This specification does not define what format of timezone identifiers should be used. It is possible that timezone identifiers from different publishers overlap, and there might be a need for a provider to distinguish those with some form of "namespace" prefix identifying the publisher. However, development of a standard (global) timezone identifier naming scheme is out of scope for this specification.
Timezone aliases map a name onto a timezone identifier. For example "US/Eastern" is usually mapped on to "America/New_York". Timezone aliases are typically used interchangeably with timezone identifiers when presenting information to users.
A timezone service needs to maintain timezone alias mapping information, and expose that data to clients as well as allow clients to query for timezone data using aliases. When returning timezone data to a client, the server returns the data with an identifier matching the query, but it can include one or more equivalent identifiers in the data to provide a hint to the client that alternative identifiers are available. For example, a query for "US/Eastern" could include equivalent identifiers for "America/New_York" or "America/Montreal".
Localized names are names for timezones which can be presented to a user in their own language. Each timezone may have one or more localized names associated with it. Names would typically be unique in their own locale as they might be presented to the user in a list.
A timezone service might need to maintain localized name information, for one or more chosen languages, as well as allow clients to query for timezone data using localized names.
Timezones and daylight saving times rules have been in use for over a century. Timezone data can thus contain a large amount of "historical" information that may not be relevant for a particular server's intended clients. For example, calendaring and scheduling clients are likely most concerned with timezone data that covers a period for one or two years in the past on into the future, as users typically only create new events for the present and future. To avoid having to send unnecessary data, servers are allowed to truncate timezone data at some appropriate date in the past, and only provide accurate offsets and rules from that point on. The server will need to advertise the cut-off dates it is using so that clients that need timezone data for earlier dates can take appropriate action. To simplify the set of data a server needs to support, truncation always occurs at the start of a year, i.e., midnight on 1st January for the timezone's local time. A server will advertise a set of years for truncated data it can supply, or provide an indicator that it can truncate at any past year. In addition, the server will advertise that it can supply untruncated data. In the absence of any indication of truncated data available on the server, the server will only supply untruncated data.
When truncating a "VTIMEZONE" component, the server MUST include either a "STANDARD" or "DAYLIGHT" sub-component with a "DTSTART" property value that matches the date-time where the truncation occurred, and appropriate "UTC-OFFSET-FROM" and "UTC-OFFSET-TO" properties to indicate the correct offset in effect right after the point of truncation. This sub-component thus represents the earliest valid date-time covered by the timezone data in the truncated "VTIMEZONE" component.
The timezone service protocol uses HTTP [RFC2616] for query and delivery of data. Queries are made on a single HTTP resource using the GET method, with specific client request attributes passed in request-URI parameters.
The "action" request-URI parameter defines the overall function being requested, with other request parameters acting as arguments to that function.
Most security considerations are already handled adequately by HTTP. However, given the nature of the data being transferred and the requirement it be correct, all interactions between client and server SHOULD use an HTTP connection protected with TLS [RFC5246] as defined in [RFC2818].
Timezone identifiers, aliases or localized names can be used to query for timezone data. This will be more explicitly defined below for each action. In general however, if a "tzid" request parameter is used then the value may be an identifier or an alias. When the "name" parameter is used it may be an identifier, an alias or a localized name.
The default format for returning timezone definitions is the iCalendar [RFC5545] data format. In addition, the iCalendar-in-XML [RFC6321], and iCalendar-in-JSON [I-D.ietf-jcardcal-jcal] representations are also available. The "format" request-URI parameter can be used to select which data format is returned.
Timezone data is generally slow moving, with the set of timezones that change from even year-to-year being relatively small. However, any changes that do occur, need to be distributed in a timely manner. Typically it is more efficient to just provide the set of changes to timezone data, so a client can do updates to any locally cached data.
When listing timezones, a timestamp is returned by the server, and that can be used later by clients to determine if any "substantive" change has occurred in the timezone data. Clients can use a conditional "list" action (see Section 6.2), supplying a previous timestamp value, to limit the results to timezones which have changed in a "substantive" manner since that previous timestamp. This allows clients to cache the last timestamp and to periodically poll the server for possible changes.
A "substantive" change is one which affects the calculated onsets for a timezone. Changes to properties such as a description are not treated as a "substantive" change.
Clients SHOULD poll for such changes at least once a day. A server acting as a local provider, caching timezone data from another server, SHOULD poll for changes once per hour. See Section 9 on expected client and server behavior regarding high request rates.
Determining timezone offsets at a particular point in time is often a complicated process, as the rules for daylight saving time can be complex. To help with this, the timezone service provides an action that allows clients to request the server to expand a timezone definition into a set of "observances" over a fixed period of time (see Section 6.4). Each of these observances describes a local onset time and UTC offsets for the prior time and the observance time. Together, these provide a quick way for "thin" clients to determine an appropriate UTC offset for an arbitrary date without having to do full timezone expansion themselves.
To enable a simple client implementation, servers SHOULD ensure that they provide or cache data for all commonly used timezones, from various publishers. That allows client implementations to configure a single server to get all timezone data. In turn, any server can refresh any of the data from any other server - though the root servers may provide the most up-to-date copy of the data.
The following are examples of response codes one would expect to be used by the server. Note, however, that unless explicitly prohibited any 2/3/4/5xx series response code may be used in a response.
When an error status is set the server SHOULD respond with some descriptive text in an error object as per Section 7.4. In the case of an invalid "action" query parameter, the following error code can be used:
This protocol is designed to be extensible through a standards based registration mechanism (see Section 10). It is anticipated that other useful timezone actions will be added in the future (e.g., mapping a geographical location to timezone identifiers, getting change history for timezones), and so, servers MUST return a description of their capabilities. This will allow clients to determine if new features have been installed and, if not, fall back on earlier features or disable some client capabilities.
Client implementations need to either know where the timezone service is located or discover it through some mechanism. To use a timezone service, a client needs a fully qualified domain name (FQDN), port and HTTP request-URI path.
[RFC2782] defines a DNS-based service discovery protocol that has been widely adopted as a means of locating particular services within a local area network and beyond, using SRV RR records. This can be used to discover a service's FQDN and port.
This specification adds two service types for use with SRV records:
Clients MUST honor "TTL", "Priority" and "Weight" values in the SRV records, as described by [RFC2782].
Example: service record for server without transport layer security
_timezone._tcp SRV 0 1 80 tz.example.com.
Example: service record for server with transport layer security
_timezones._tcp SRV 0 1 443 tz.example.com.
When SRV RRs are used to advertise a timezone service, it is also convenient to be able to specify a "context path" in the DNS to be retrieved at the same time. To enable that, this specification uses a TXT RR that follows the syntax defined in Section 6 of [RFC6763] and defines a "path" key for use in that record. The value of the key MUST be the actual "context path" to the corresponding service on the server.
A site might provide TXT records in addition to SRV records for each service. When present, clients MUST use the "path" value as the "context path" for the service in HTTP requests. When not present, clients use the ".well-known" URI approach described next.
Example: text record for service with transport layer security
_timezones._tcp TXT path=/timezones
A "well-known" URI [RFC5785] is registered by this specification for the Timezone service, "timezone" (see Section 10). This URI points to a resource that the client can use as the initial "context path" for the service they are trying to connect to. The server MUST redirect HTTP requests for that resource to the actual "context path" using one of the available mechanisms provided by HTTP (e.g., using an appropriate 3xx status response). Clients MUST handle HTTP redirects on the ".well-known" URI. Servers MUST NOT locate the actual timezone service endpoint at the ".well-known" URI as per Section 1.1 of [RFC5785].
Servers SHOULD set an appropriate Cache-Control header value (as per Section 14.9 of [RFC2616]) in the redirect response to ensure caching occurs as needed, or as required by the type of response generated. For example, if it is anticipated that the location of the redirect might change over time, then a "no-cache" value would be used.
To facilitate "context path's" that might differ from user to user, the server MAY require authentication when a client tries to access the ".well-known" URI (i.e., the server would return a 401 status response to the unauthenticated request from the client, then return the redirect response only after a successful authentication by the client).
A Timezone server has a "context path" that is "/servlet/timezone". The client will use "/.well-known/timezone" as the path for the service after it has first found the FQDN and port number via an SRV lookup or via manual entry of information by the user. When the client makes its initial HTTP request against "/.well-known/timezone", the server would issue an HTTP 301 redirect response with a Location response header using the path "/servlet/timezone". The client would then "follow" this redirect to the new resource and continue making HTTP requests there.
When a secondary service or a client wishing to cache all timezone data first starts, or wishes to do a full refresh, it synchronizes with another server by first issuing a "list" action. The client would preserve the returned datestamp for subsequent use. Each timezone in the returned list can then be fetched and stored locally. In addition a mapping of aliases to timezones can be built.
A secondary service or a client caching all timezone data needs to periodically synchronize with a server. To do so it would issue a "list" action with the "changedsince" parameter set to the value of the datestamp returned by the last synchronization. The client would again preserve the returned datestamp for subsequent use. Each timezone in the returned list can then be fetched and stored locally.
Note, this process makes no provision for handling deleted timezones. In general it is bad practice to delete timezones as they might still be in use by consumers of timezone data.
The "action" request-URI parameter MUST be included in all requests to define what action is required of the server.
The following request-URI parameters are used with the various actions.
Example: a server that can only return one set of truncated data - client can omit the "truncate" query parameter:
truncated: {
"any": false,
"years": [1970],
"untruncated": false
}
Example: a server that can return truncated data for any past year as well as untruncated data if client omits the "truncate" query parameter:
truncated: {
"any": true,
"untruncated": true
}
Example: a server that can return only untruncated data - the "truncate" query parameter would always be omitted:
truncated: {
"any": false,
"untruncated": true
}
Servers MUST support the following actions.
>> Request <<
GET /?action=capabilities HTTP/1.1
Host: tz.example.com
>> Response <<
HTTP/1.1 200 OK
Date: Wed, 4 Jun 2008 09:32:12 GMT
Content-Type: application/json; charset="utf-8"
Content-Length: xxxx
{
"version": 1,
"info": {
"primary-source": "Olson:2011m",
"truncate" : {
"any": false,
"years": [1970, 2000, 2010],
"untruncated": true
},
"contacts": ["mailto:tzs@example.org"]
},
"actions": [
{
"name": "list",
"parameters": [
{
"name": "lang",
"required": false,
"multi": true
},
{
"name": "changedsince",
"required": false,
"multi": false
}
]
},
{
"name": "get",
"parameters": [
{
"name": "format",
"required": false,
"multi": false,
"values": [
"text/calendar",
"application/calendar+xml",
"application/calendar+json"
]
},
{
"name": "lang",
"required": false,
"multi": true
},
{
"name": "tzid",
"required": true,
"multi": false
},
{
"name": "truncate",
"required": false,
"multi": false
}
]
},
{
"name": "expand",
"parameters": [
{
"name": "tzid",
"required": true,
"multi": false
},
{
"name": "start",
"required": false,
"multi": false
},
{
"name": "end",
"required": false,
"multi": false
}
]
},
{
"name": "find",
"parameters": [
{
"name": "name",
"required": true,
"multi": false
},
{
"name": "lang",
"required": false,
"multi": true
}
]
},
{
"name":"capabilities",
"parameters": []
}
]
}
In this example the client requests the timezone identifiers and in addition requests that the US-English local names be returned.
>> Request <<
GET /?action=list&lang=en_US HTTP/1.1
Host: tz.example.com
>> Response <<
HTTP/1.1 200 OK
Date: Wed, 4 Jun 2008 09:32:12 GMT
Content-Type: application/json; charset="utf-8"
Content-Length: xxxx
{
"dtstamp": "2009-10-11T09:32:11Z",
"timezones": [
{
"tzid": "America/New_York",
"last-modified": "2009-09-17T01:39:34Z",
"aliases":["US/Eastern"],
"local-names": [
{
"name": "America/New_York",
"lang": "en_US"
}
]
},
...
]
}
In this example the client requests the timezone with a specific timezone identifier to be returned
>> Request <<
GET /?action=get&tzid=America/New_York
&format=text/calendar HTTP/1.1
Host: tz.example.com
>> Response <<
HTTP/1.1 200 OK
Date: Wed, 4 Jun 2008 09:32:12 GMT
Content-Type: text/calendar; charset="utf-8"
Content-Length: xxxx
ETag: "123456789-000-111"
BEGIN:VCALENDAR
...
BEGIN:VTIMEZONE
TZID:America/New_York
...
END:VTIMEZONE
END:VCALENDAR
In this example the client requests the timezone with an aliased timezone identifier to be returned, and the server returns the timezone data with that identifier, and two equivalents
>> Request <<
GET /?action=get&tzid=US/Eastern
&format=text/calendar
&truncate=2000 HTTP/1.1
Host: tz.example.com
>> Response <<
HTTP/1.1 200 OK
Date: Wed, 4 Jun 2008 09:32:12 GMT
Content-Type: text/calendar; charset="utf-8"
Content-Length: xxxx
ETag: "123456789-000-111"
BEGIN:VCALENDAR
...
BEGIN:VTIMEZONE
TZID:US/Eastern
EQUIVALENT-TZID:America/New_York
EQUIVALENT-TZID:America/Montreal
...
END:VTIMEZONE
END:VCALENDAR
Assume the server advertises a "truncated" object in its "capabilities" response that appears as:
truncated: {
"any": false,
"years": [1970, 2000],
"untruncated": false
}
In this example the client requests the timezone with a specific timezone identifier truncated at one of the years specified as available by the server, to be returned
>> Request <<
GET /?action=get&tzid=America/New_York
&format=text/calendar
&truncate=2000 HTTP/1.1
Host: tz.example.com
>> Response <<
HTTP/1.1 200 OK
Date: Wed, 4 Jun 2008 09:32:12 GMT
Content-Type: text/calendar; charset="utf-8"
Content-Length: xxxx
ETag: "123456789-000-111"
BEGIN:VCALENDAR
...
BEGIN:VTIMEZONE
TZID:America/New_York
...
END:VTIMEZONE
END:VCALENDAR
In this example the client requests a timezone in the expanded form.
>> Request <<
GET /?action=expand&tzid=America/New_York HTTP/1.1
Host: tz.example.com
>> Response <<
HTTP/1.1 200 OK
Date: Mon, 11 Oct 2009 09:32:12 GMT
Content-Type: application/json; charset="utf-8"
Content-Length: xxxx
ETag: "123456789-000-111"
{
"dtstamp": "2009-10-11T09:32:11Z",
"observances": [
{
"name": "Daylight",
"onset": "2008-03-09T07:00:00Z",
"utc-offset-from": -18000,
"utc-offset-to": -14400
},
{
"name": "Standard",
"onset": "2008-11-02T06:00:00Z",
"utc-offset-from": -14400,
"utc-offset-to": -18000
},
{
"name": "Daylight",
"onset": "2009-03-08T07:00:00Z",
"utc-offset-from": -18000,
"utc-offset-to": -14400
},
...
]
}
In addition, when matching, underscore characters (0x5F) SHOULD be mapped to a single space character (0x20) prior to string comparison. This allows timezone identifiers such as "America/New_York" to match a query for "*New York*". ASCII characters in the range 0x41 ("A") through 0x5A ("Z") SHOULD be mapped to their lowercase equivalents.
In this example the client asks for data about the timezone "US/Eastern".
>> Request <<
GET /?action=find&name=US/Eastern HTTP/1.1
Host: tz.example.com
>> Response <<
HTTP/1.1 200 OK
Date: Wed, 4 Jun 2008 09:32:12 GMT
Content-Type: application/json; charset="utf-8"
Content-Length: xxxx
{
"dtstamp": "2009-10-11T09:32:11Z",
"timezones": [
{
"tzid": "America/New_York",
"last-modified": "2009-09-17T01:39:34Z",
"aliases":["US/Eastern"],
"local-names": [
{
"name": "America/New_York",
"lang": "en_US"
}
]
},
{
"tzid": "America/Detroit",
"last-modified": "2009-09-17T01:39:34Z",
"aliases":["US/Eastern"],
"local-names": [
{
"name": "America/Detroit",
"lang": "en_US"
}
]
},
...
]
}
JSON members used by this specification are defined here using the syntax in [I-D.newton-json-content-rules]. Clients MUST ignore any JSON members they do not expect.
JSON Content Rules for the JSON document returned for a "capabilities" action request.
; root object
root {
version,
info,
actions
}
; The version number of the protocol supported - MUST be 1
version "version" : integer 1..1
; object containing service information
info "info" {
primary_source / secondary_source,
?truncated,
contacts
}
; The source of the timezone data provided by a "primary" server
primary_source "primary-source" : string
; The timezone server from which data is provided by a "secondary"
; server
secondary_source "secondary-source" : uri
; Present if the server is providing truncated timezone data. The
; value is the truncation date-time. Timezone data will not be
; valid for dates prior to this value.
; [RFC3339] UTC value
truncated "truncated" : {
any,
?years,
?untruncated
}
; Indicates whether the server can truncate timezone data at any year
; boundary in the past. When set to "true" any past year is a valid
; value for use with the "truncated" query parameter in an action
; "get" request
any "any" : boolean
; Indicates which year boundaries the server has truncated data for.
; A value from this list may be used with the "truncated" query
; parameter in an action "get" request. Not present if "any" is set
; to "true"
years "years" : [ * : integer ]
; Indicates whether the server can can supply untruncated data. When
; set to "true" indicates that, in addition to truncated data being
; available, the server can return untruncated data if an action "get"
; request is executed without a "truncated" query parameter
untruncated "untruncated" : boolean
; Array of URIs providing contact details for the server
; administrator
contacts "contacts" [ * : uri ]
; Array of actions supported by the server
actions "actions" [ * action ]
; An action supported by the server
action {
action_name,
action_params
}
; Name of the action
action_name "name" : string
; Array of request-URI query parameters supported by the action
action_params "parameters" [ * parameter ]
; Object defining an action parameter
parameter {
param_name,
?param_required,
?param_multi,
?param_values
}
; Name of the parameter
param_name "name" : string
; If true the parameter has to be present in the request-URI
; default is false
param_required "required" : boolean
; If true the parameter can occur more than once in the request-URI
; default is false
param_multi "multi" : boolean,
; An array that defines the allowed set of values for the parameter
; In the absence of this member, any string value is acceptable
param_values "values" [ * : string ]
JSON Content Rules for the JSON document returned for a "list" action request.
; root object
root {
dtstamp,
timezones
}
; Server generated timestamp used for synchronizing changes,
; [RFC3339] UTC value
dtstamp "dtstamp" : date-time
; Array of timezone objects
timezones "timezones" [ * timezone ]
; Information about a timezone available on the server
timezone {
tzid,
last_modified,
?aliases,
?local_names,
}
; Timezone identifier
tzid "tzid" : string
; Date/time when the timezone data was last modified
; [RFC3339] UTC value
last_modified "last-modified" : date-time
; An array that lists the set of timezone aliases available
; for the corresponding timezone
aliases "aliases" [ * : string ]
; An array that lists the set of localized names available
; for the corresponding timezone
local_names "local-names" [ * local_name ]
local_name [lang, lname, ?pref]
; Language tag for the language of the associated name
lang : string
; Localized name
lname : string
; Indicates whether this is the preferred name for the associated
; language default: false
pref : boolean
JSON Content Rules for the JSON document returned for a "expand" action request.
; root object
root {
dtstamp,
observances
}
; Server generated timestamp used for synchronizing changes
; [RFC3339] UTC value
dtstamp "dtstamp" : date-time
; Array of timezone objects
observances "observances" [ * observance ]
; Information about a timezone available on the server
observance {
oname,
?olocal_names,
onset,
utc_offset_from,
utc_offset_to
}
; Observance name
oname "name" : string
; Array of localized observance names
olocal_names "local-names" [ * : string]
; The local time at which the observance takes effect
; [RFC3339] value modified to exclude "time-offset" part
onset "onset" : date-time
; The UTC offset in seconds before the start of this observance
utc_offset_from "utc-offset-from" : integer
; The UTC offset in seconds at and after the start of this observance
utc_offset_to "utc-offset-to" : integer
JSON Content Rules for the JSON document returned when an error occurs.
; root object
root {
error,
?description
}
; Error code
error "error" : string
; Description of the error
description "description" : string
equivalent-tzid = "EQUIVALENT-TZID" etzidpropparam ":"
[tzidprefix] text CRLF
etzidpropparam = *(";" other-param)
;tzidprefix defined in [RFC5545].
EQUIVALENT-TZID:US/Eastern
Timezone data is critical in determining local or UTC time for devices and in calendaring and scheduling operations. As such, it is vital that a reliable source of timezone data is used. Servers providing a timezone service MUST support HTTP over Transport Layer Security (TLS) (as defined by [RFC2818]) with a valid certificate. Clients and servers making use of a timezone service SHOULD use HTTP over TLS and verify the authenticity of the service being used before accepting and using any timezone data from that source.
Clients that support transport layer security as defined by [RFC2818] SHOULD try the "_timezones" service first before trying the "_timezone" service. Clients MUST follow the certificate verification process specified in [RFC6125].
A malicious attacker with access to the DNS server data, or able to get spoofed answers cached in a recursive resolver, can potentially cause clients to connect to any server chosen by the attacker. In the absence of a secure DNS option, clients SHOULD check that the target FQDN returned in the SRV record matches the original service domain that was queried. If the target FQDN is not in the queried domain, clients SHOULD verify with the user that the SRV target FQDN is suitable for use before executing any connections to the host.
Timezone servers SHOULD protect themselves against errant or malicious clients by throttling high request rates or frequent requests for large amounts of data. Clients can avoid being throttled by using the polling capabilities outlined in Section 4.1.3
This specification defines a new registry of "actions" for the timezone service protocol, defines a "well-known" URI using the registration procedure and template from Section 5.1 of [RFC5785], creates two new SRV service label aliases, and defines one new iCalendar property parameter as per the registration procedure in [RFC5545].
This section defines the process to register new or modified timezone service actions with IANA.
The IETF will create a mailing list, timezone-service@ietf.org, which can be used for public discussion of timezone service actions proposals prior to registration. Use of the mailing list is strongly encouraged. The IESG will appoint a designated expert who will monitor the timezone-service@ietf.org mailing list and review registrations.
Registration of new timezone service actions MUST be reviewed by the designated expert and published in an RFC. A Standard Tracks RFC is REQUIRED for the registration of new timezone service actions. A Standard Tracks RFC is also REQUIRED for changes to actions previously documented in a Standard Tracks RFC.
The registration procedure begins when a completed registration template, defined in the sections below, is sent to timezone-service@ietf.org and iana@iana.org. The designated expert is expected to tell IANA and the submitter of the registration within two weeks whether the registration is approved, approved with minor changes, or rejected with cause. When a registration is rejected with cause, it can be re-submitted if the concerns listed in the cause are addressed. Decisions made by the designated expert can be appealed to the IESG Applications Area Director, then to the IESG. They follow the normal appeals procedure for IESG decisions.
An action is defined by completing the following template.
An action parameter is defined by completing the following template.
The IANA is requested to create and maintain the following registries for timezone service actions with pointers to appropriate reference documents.
The following table is to be used to initialize the actions registry.
| Action Name | Status | Reference |
|---|---|---|
| capabilities | Current | RFCXXXX, Section 6.1 |
| list | Current | RFCXXXX, Section 6.2 |
| get | Current | RFCXXXX, Section 6.3 |
| expand | Current | RFCXXXX, Section 6.4 |
| find | Current | RFCXXXX, Section 6.5 |
The following table is to be used to initialize the parameters registry.
| Parameter | Status | Reference |
|---|---|---|
| action | Current | RFCXXXX, Section 5.1 |
| changedsince | Current | RFCXXXX, Section 5.3 |
| end | Current | RFCXXXX, Section 5.5 |
| format | Current | RFCXXXX, Section 5.2 |
| lang | Current | RFCXXXX, Section 5.6 |
| name | Current | RFCXXXX, Section 5.8 |
| start | Current | RFCXXXX, Section 5.4 |
| truncate | Current | RFCXXXX, Section 5.9 |
| tzid | Current | RFCXXXX, Section 5.7 |
This document registers two new service names as per [RFC6335]. Both are defined within this document.
This document defines the following new iCalendar property to be added to the registry defined in Section 8.2.3 of [RFC5545]:
| Property | Status | Reference |
|---|---|---|
| EQUIVALENT-TZID | Current | RFCXXXX, Section 8 |
The authors would like to thank the members of the Calendaring and Scheduling Consortium's Timezone Technical Committee and the following individuals for contributing their ideas and support: Steve Allen, Steve Crocker, John Haug, Ciny Joy, Bryan Keller, Andrew McMillan, Ken Murchison, Arnaud Quillaud, and Jose Edvaldo Saraiva.
The authors would also like to thank the Calendaring and Scheduling Consortium for advice with this specification.
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