SIP SIMPLE Client SDK

= XMPP gateway architecture =

<abbr title="DesignXMPP, DesignXMPP_analysis, DesignXMPP_arch, DesignXMPP_im, depth=2">TOC</abbr>

The architecture of the SIP-XMPP gateway can be modeled in two different ways:

• Based on an XMPP component
• Based on an XMPP server (using server-to-server communication)

Both approaches are not mutually exclusive, they can both be implemented at the same time and decide which one to use with a configuration option to allow different deployment scenarios.

XMPP component based architecture

Image(xmppgw-arch-component.png, 700px, center)

=== Elements required ===

• XMPP server (ejabberd for example)
• XMPP server plugin (divert stanzas to offline users to a given component)
• SIP Application server which is also a XMPP component
• SIP proxy (registration, AAA and routing)

XMPP server based architecture

Image(xmppgw-arch-server.png, 700px, center)

=== Elements required ===

• SIP Application server which is also a XMPP server
• SIP proxy (registration, AAA and routing)

Chosen architecture

After experimenting with both models the chosen model to be implemented first is the '''XMPP server based architecture'''. The component based approach shall be added at a later time.

The chosen model has a number of advantages / disadvantages:

• Advantages * Less network elements involved * Full control over XMPP routing since the server is customized * No need for developing plugins for any XMPP server
• Disadvantages: * Inability to use an XMPP client in the local domain

The critical factor when making this choice is the fact that if a custom XMPP server is built all the routing logic can be customized without the need of running an extra XMPP server and writing a plugin for it. Thus, this approach is more sustainable over time.

The aforementioned disadvantage would also disappear if the chosen library implemented accepting XMPP client connections, which is likely to happen in the future.