XMPP Glossary

Roster, JID, full JID or bare JID, BOSH, caps, component, C2S and S2S, MUC, federation, dialback, PubSub, service discovery, resource, priority, transport, stanza, IQ, spim, ICE/STUN/TURN, presence, Jingle, and… Jabber. Maybe most of all these terms mean something to you. But some may not have a meaning in the XMPP context, or some just do not mean anything.

A

Address book: see roster

Ad-Hoc Commands: wizard-type commands exchanged between 1

Affiliation: in MUC, it is a long-lived privilege set

Attention: specific packet sent to get attention from a contact

Attribute: XML key-value pair that qualifies an element, example <element key=’value’ /> (see element)

Authentication: process by which an XMPP server verifies that a user is really legitimate to connect to an account

Avatar: image chosen by a user to visually represent himself

B

Bare JID: JID without the resource, in the form username@domain

Bind: process by which a client-to-server (C2S) connection is linked to a resource name

Blocking: exhaustive framework for filtering incoming and outgoing traffic via Privacy Lists, as well as simple user blocking via Simple Communications Blocking

Bookmark: server-side saved links to chat rooms (and optionally HTTP links)

BOSH: technique simulating a TCP connection with two long-lived HTTP requests

Bot: a client or component that behaves automatically, usually used as a service or a game

C

Caps: entity capabilities transported by presence

CAPTCHA: challenge for robots, helps identify humans

Chat: real time/synchronous textual conversation

Chatroom: virtual place where multiple users can chat together (see Multi-User Chat)

Chat State Notifications: notifications telling a user is giving attention to a chat, is writing, etc.

Chat theme: set chat window decorations

Client: user-side software the connects to a server and lets the user interact with contacts

Component: server-side software linked to a server

Compression: enables traffic compression between two connected entities (it can be based on stream or TLS)

Contact: another entity generally in the user’s roster

Contact list: see roster

C2S: client-to-server connection

D

Dial-back: in S2S, a mechanism in which a servers calls another one then hangs up, then the second one must callback the first one: this prevents server identity theft

Directory: list of users and search interface on a server

Disco: see Service discovery

E

Element: basic atomic in XML, for example <element/> or <element>content</element>, see XML

Entity: an addressable client, server or component

Event: in PubSub, a notification or payload

E2E: end-to-end encryption, encryption from the sender entity to the receiver entity, even the intermediary servers can’t read the content

F

Federation: interconnection of multiple servers, that enables the users to interact all together

File transfer: process of file exchange between two (or more) entities, it may be synchronous or not

Full JID: JID including the resource, in the form username@domain/resource

G

Gateway: see transport

Geo-location: location transported by PEP

Group: in the roster, a group of contacts is a label put on roster items

Group-chat: see MUC

H

HTTP Binding: see BOSH

HTTP Polling: deprecated method of doing XMPP over HTTP

I

ICE: NAT traversal technique mixing direct connection STUN and TURN

Instant messaging: or IM, also called chat, lets people chat interactively instantaneously

Invitation: packet sends from a room or an entity inviting another entity to join a room

In-band: traffic inside the <stream/> element, see out-of-band

Info-Query: IQ, see query

IQ: short for Info-Query, see query

J

Jabber: former name of XMPP

Jabber address: see JID

Jabber ID: see JID

JEP: former name of XEP

JID: the addressable name of an entity in the form of user@domain (user is optional), see bare JID and full JID

Jingle: negotiation technique enabling voice, video, file transfer, reatime collab apps, and any other heavy binary duty that is not suitable in-band

Jingle Relay Nodes: distributable piece of software that acts as a relay for out-of-band data for peers

Join: process of joining a MUC

JSF: stands for “Jabber Software Foundation”, see XSF

JUD: Jabber User Directory

K

Keep-alive: white-spaces that are sent between two entities directly connected to avoid network hops timeouts

L

Location: see geolocation

M

Message: XML element, first child of the <stream/> element, conveys textual messages between users (and more, like meta data), notation <message/>

MUC: see Multi-User Chat

Multi-User Chat: service for chatrooms

N

Namespace: method to avoid element name conflicts

NAT: stands for “Network Address Translation”, IP-level network device meant to remap addresses

Nick, nickname: pseudonym used in the context of MUC

Node: in the context of PubSub, a please where a publisher publishes information

Notification: event meta-data, which may contain a payload, and may be pushed or polled

O

Offline messages: messages saved by the server, and delivered to the receiver after his reconnection

Out-of-band: traffic outside the <stream/> element

P

Payload: actual content of a notification

PEP: see Personal Eventing Protocol

Personal Eventing Protocol: also known as PubSub on JID

Ping: XMPP-based mechanism to ping an XMPP entity

PLAIN: method of authentication where the password is sent unencrypted, but hashed, via SASL

Port: IP-based addressing number to multiplex traffic

Presence: stanza distributed to subscribed contacts, notation <presence/>

Priority: weight to prioritize client connections using the same bare JID

Privacy lists: lists of filters for stanzas

Private XML Storage: per-account server-side storage space

Protocol: set of rules that define a way to communicate

Proxy: network device that relays requests and/or traffic

Proxy65: XMPP protocol extension based on SOCKS5 to allow out-of-band file transfers

PubSub: specification and implementation of a publish-subscribe messaging pattern

Publish-subscribe: see PubSub

Push: technique that enables a sender to transmit data to receivers, instead of having the receivers polling the sender

Q

Query: stanza <iq/> that needs a response, that enables an entity to query/send info or make actions to another entity

R

Receipts: acknowledgements that a message is received by an entity

Registration: creation of an account

Resource: name given to differentiate client connections to the same account. There can not be two connections with the same resource. Different policies apply: either the new or the old one is disconnected by the server, or the new one is forbidden.

Robot: see bot

Roles: in MUC, it is a short-lived privilege set

Room: a MUC room, where participants send and receive presence and messages

Roster: a contact list (or address book) containing JIDs, nicknames, groups (like labels) and subscriptions to each other’s presence

S

SASL: stands for Simple Authentication and Security Layer, it is a framework for authentication and data security in Internet protocols

Server: network entity that manages C2S, S2S, etc.

Service: an XMPP service, like MUC, PubSub, or transport

Service discovery: a mechanism to browse the services offered by an entity

Simple Communications Blocking: enables the blocking of all communications with a specific contact, see Privacy Lists

SOCKS5: proxy-based file transfer mechanism

Spim: spam on IM

SSL: see TLS

Standards Track: XMPP specifications that are valid for implementation

Stanza: the first-child element of a stream, the smallest unit of XML exchanged between two connected entities, may be <IQ/>, <message/>, or <presence/>

Status: a natural language sentence, transported by presence

Stream: root element or an XMPP traffic

STUN: mechanism to exchange external IP addresses for entities behind a NAT

Subscription: a mechanism for an entity manually authorize another to subscribe to his presence

S2S: server-to-server connection, enables federation

T

TCP: lossless low-level transport for network packets

Thread: within the context of a chat, linked messages that form a consistent conversation

TLS: mechanism to encrypt the stream-level traffic, used for C2S and S2S traffic

Traffic shaping: server-side mechanism to limit the incoming traffic from a client

Transport: a service that provides a gateway to a third party IM (or other communication mean)

TURN: media relay proxy

U

UDP: low-level transport for network packets

URI: unique address of an entity

V

vCard: self-filled set of information about a user, aka profile

W

Whiteboard: real-time collaborative draw

X

XEP: specification that extends XMPP

XHTML-IM: chat formatting

XML: markup language used as the basis of almost all XMPP communication

XMPP: realt-ime communication protocol

XSF: XMPP Standards Foundation, the standards organization that edits XEP and promotes the protocol

5

5222: standard C2S port

5223: legacy SSL port

5269: standard S2S port

5280: standard BOSH port

If you find that a definition is lacking, if you find an error, or if you simply want to extend it, please feel free: you are highly encouraged to contribute.