In XMPP, rosters and presence subscriptions have been used to date only among IM users (see XMPP IM [1]). However, nothing prevents the application of these concepts to other XMPP entities, such as components and servers. Given that a presence subscription typically indicates some level of trust in a peer, server deployments can use the sharing of XMPP presence information as a way to indicate that a given server has a trust relationship with a peer server. The server might then share certain kinds of additional information only with trusted peers (for example, incident reports).
To establish a trust relationship with a peer, a server shall send a presence subscription request to the peer, just as is done between XMPP users.
<presence from='montague.lit'
to='capulet.lit'
type='subscribe'/>
A server MUST NOT send such a presence subscription request unless explicitly requested to do so by the server administrator(s).
Upon receiving such a presence subscription request, the XMPP server software running at the peer MUST prompt the server administrator(s) to approve the request, rather than automatically approving it. Methods for doing so are out of scope for this specification.
If the server administrator(s) approve the request, the peer server shall then inform the originating server that the request has been approved.
<presence from='capulet.lit'
to='montague.lit'
type='subscribed'/>
The peer SHOULD also send a subscription request to the originating server.
<presence from='capulet.lit'
to='montague.lit'
type='subscribe'/>
If an XMPP server implementation supports this usage of presence subscriptions, it MUST keep a list of approved entities, which we denote a "server roster". The implementation MAY use that roster for access control purposes defined in other specifications.
To follow.
This document requires no interaction with the Internet Assigned Numbers Authority (IANA) [2].
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The Extensible Messaging and Presence Protocol (XMPP) is defined in the XMPP Core (RFC 6120) and XMPP IM (RFC 6121) specifications contributed by the XMPP Standards Foundation to the Internet Standards Process, which is managed by the Internet Engineering Task Force in accordance with RFC 2026. Any protocol defined in this document has been developed outside the Internet Standards Process and is to be understood as an extension to XMPP rather than as an evolution, development, or modification of XMPP itself.
There exists a special venue for discussion related to the technology described in this document: the <operators@xmpp.org> mailing list.
The primary venue for discussion of XMPP Extension Protocols is the <standards@xmpp.org> discussion list.
Discussion on other xmpp.org discussion lists might also be appropriate; see <https://xmpp.org/community/> for a complete list.
Errata can be sent to <editor@xmpp.org>.
The following requirements keywords as used in this document are to be interpreted as described in RFC 2119: "MUST", "SHALL", "REQUIRED"; "MUST NOT", "SHALL NOT"; "SHOULD", "RECOMMENDED"; "SHOULD NOT", "NOT RECOMMENDED"; "MAY", "OPTIONAL".
1. RFC 6121: Extensible Messaging and Presence Protocol (XMPP): Instant Messaging and Presence <http://tools.ietf.org/html/rfc6121>.
2. The Internet Assigned Numbers Authority (IANA) is the central coordinator for the assignment of unique parameter values for Internet protocols, such as port numbers and URI schemes. For further information, see <http://www.iana.org/>.
Note: Older versions of this specification might be available at https://xmpp.org/extensions/attic/
First draft, split from the incident reporting proposal.
@report{hefczyc2009xepxxxx,
title = {Server Rosters},
author = {Hefczyc, Artur and Jensen, Florian and Rémond, Mickaël and Saint-Andre, Peter and Wild, Matthew},
type = {XEP},
number = {xxxx},
version = {0.0.1},
institution = {XMPP Standards Foundation},
url = {https://xmpp.org/extensions/xep-xxxx.html},
date = {2009-04-30/2009-04-30},
}END