Jabber Technical Overview Presenter: Ming-Wei Lin

Introduction The term "Jabber" is widely used to refer to a set of open protocols for streaming XML elements between any two points on a network, and to the technologies built using those protocols The term "Jabber" is widely used to refer to a set of open protocols for streaming XML elements between any two points on a network, and to the technologies built using those protocols The core protocols provide an XML streaming infrastructure that has been used to build a wide variety of real-time communications systems. The core protocols provide an XML streaming infrastructure that has been used to build a wide variety of real-time communications systems.

A Quick Example The architecture of Jabber IM systems is extremely similar to that of the most time-tested messaging system on the planet: The architecture of Jabber IM systems is extremely similar to that of the most time-tested messaging system on the planet:

Architectural Foundations Communications both in and in Jabber are made possible by a distributed network of servers that use a common protocol Communications both in and in Jabber are made possible by a distributed network of servers that use a common protocol Specialized clients connect to servers in order to receive messages from other users and send messages to users on the same server or any other server that is connected to the network Specialized clients connect to servers in order to receive messages from other users and send messages to users on the same server or any other server that is connected to the network Jabber servers deliver messages in close to real time Jabber servers deliver messages in close to real time

Architectural Foundations (cont.) Three additional features Three additional features The first is a set of open, well-documented, easy-to- understand protocols The first is a set of open, well-documented, easy-to- understand protocols The second is the fact that the Jabber protocols are 100% XML The second is the fact that the Jabber protocols are 100% XML The third is that Jabber uses addresses that are based on DNS and recognized URI schemes, resulting in addresses of the same form as those used in The third is that Jabber uses addresses that are based on DNS and recognized URI schemes, resulting in addresses of the same form as those used in

Client/Server Jabber technologies use a client-server architecture Jabber technologies use a client-server architecture This connection is "always-on" for the life of the client's session on the server, which means the client does not have to poll for messages as an client does. This connection is "always-on" for the life of the client's session on the server, which means the client does not have to poll for messages as an client does.

Open Protocols the original Jabber team defined an open protocol for streaming XML over the wire. the original Jabber team defined an open protocol for streaming XML over the wire. This protocol continues to grow in depth and breadth This protocol continues to grow in depth and breadth The depth comes mainly from work completed by the XMPP Working Group within the Internet Engineering Task Force (IETF) The depth comes mainly from work completed by the XMPP Working Group within the Internet Engineering Task Force (IETF) The breadth comes mainly from work by the Jabber Software Foundation in defining extensions to the core protocols for a wide variety of features, including groupchat, file transfer, service discovery, avatars, and much more. The breadth comes mainly from work by the Jabber Software Foundation in defining extensions to the core protocols for a wide variety of features, including groupchat, file transfer, service discovery, avatars, and much more.

XML Data Format XML is an integral part of Jabber technologies XML is an integral part of Jabber technologies It makes them fundamentally extensible and able to express almost any structured data It makes them fundamentally extensible and able to express almost any structured data A client connects to a server, it opens a one-way XML stream from the client to the server, and the server responds with a one-way XML stream from the server to the client. A client connects to a server, it opens a one-way XML stream from the client to the server, and the server responds with a one-way XML stream from the server to the client.

XML Data Format (cont.) Example Example Wherefore art thou, Romeo? Wherefore art thou, Romeo?

Distributed Network Each user connects to a "home" server, which receives information for them, and the servers transfer data among themselves on behalf of users. Each user connects to a "home" server, which receives information for them, and the servers transfer data among themselves on behalf of users.

Modular Servers Handling client connections and communicating directly with Jabber clients. Handling client connections and communicating directly with Jabber clients. Communicating with other Jabber servers Communicating with other Jabber servers Coordinating the various server components associated with the server. Coordinating the various server components associated with the server.

Modular Servers (cont.) Jabber servers are designed to be modular, with specific internal code packages. Jabber servers are designed to be modular, with specific internal code packages. Jabber servers can be extended with external components, which enable server administrators to supplement the core server with additional services Jabber servers can be extended with external components, which enable server administrators to supplement the core server with additional services

Simple Clients The only things a Jabber client must do are: The only things a Jabber client must do are: Communicate with the Jabber server over TCP sockets. Communicate with the Jabber server over TCP sockets. Parse and interpret well-formed XML "stanzas" over an XML stream. Parse and interpret well-formed XML "stanzas" over an XML stream. Understand the core Jabber data types Understand the core Jabber data types In practice, many of the low-level functions of the client (e.g., parsing XML and understanding the core Jabber data types) are handled by Jabber client libraries, enabling client developers to focus on the user interface In practice, many of the low-level functions of the client (e.g., parsing XML and understanding the core Jabber data types) are handled by Jabber client libraries, enabling client developers to focus on the user interface

Standards-Based Addressing There are many different entities that need to communicate with each other. These entities can represent servers, gateways, groupchat rooms, a single Jabber user, etc. Jabber IDs are used both externally and internally to express ownership or routing information. There are many different entities that need to communicate with each other. These entities can represent servers, gateways, groupchat rooms, a single Jabber user, etc. Jabber IDs are used both externally and internally to express ownership or routing information.

Standards-Based Addressing (cont.) Key characteristics of Jabber IDs include: Key characteristics of Jabber IDs include: They uniquely identify individual objects or entities for communicating instant messages and presence information. They uniquely identify individual objects or entities for communicating instant messages and presence information. They are easy for users to remember and express in the real world.Ex They are easy for users to remember and express in the real world.Ex They are flexible enough to enable the inclusion of other IM and presence schemes They are flexible enough to enable the inclusion of other IM and presence schemes

Conclusion Jabber protocols and technologies provide a true open alternative to the closed, proprietary services offered by legacy IM vendors such as AIM and MSN. Jabber protocols and technologies provide a true open alternative to the closed, proprietary services offered by legacy IM vendors such as AIM and MSN. Jabber's IETF pedigree and XML foundation enable developers to create robust, near-real-time messaging and presence solutions for IM and beyond. Jabber's IETF pedigree and XML foundation enable developers to create robust, near-real-time messaging and presence solutions for IM and beyond.