SIP SIMPLE Client SDK

= XMPP library candidates analysis =

<acronym title="DesignXMPP_analysis, depth=2">TOC</acronym>

In this phase the existing XMPP libraries will be analyzed and one will be chosen to be used throughout the project.

Library requirements * Written in Python (C/C++ could also be used, but a wrapper would need to be written) * Support for XMPP server (or component, details later) * Ability to use it with the current model used by SylkServer * Green threads * Callback based IO XMPP server vs XMPP component

The XMPP protocol was designed to be extended by entities called "components" which sit on the side of the server. A component is addressed with a DNS subdomain in the following form:

{{{
component.domain.tld
}}}

This mechanism is defined in [http://xmpp.org/extensions/xep-0114.html XEP-0114].

With this architecture in place deployment of additional features to an existing XMPP server doesn't require to modify it. The SIP-XMPP gateway can potentially be implemented as either a XMPP component or an standalone XMPP server.

Library evaluation

The following aspects were considered when evaluating a given library:

• Met requirements stated above
• Is it actively maintained?
• Example use cases
• Deployments in real-world scenarios
• Perceived complexity to integrate it with SylkServer architecture

= SleekXMPP=== * Plugin architecture, each XEP as a plugin * Client and server component support * Threaded model (thread based scheduler) * Active development

=== Wokkel ===

• Plugin architecture, 'subprotocols' implementing different XEPs
• Client and server component support
• XMPP server-to-server support (s2s)
• Designed to be used with Twisted (reactor model)
• Active development

Selected XMPP library

After analyzing candidate libraries '''Wokkel''' was the chosen one. Reasons:

• Implemented on top of Twisted, which makes integration with SylkServer straightforward
• Support for both component and XMPP server models, allowing for flexibility in implementation