Zimbra Client Architecture

Zimbra Ajax client : The full form of Ajax is Asynchronous JavaScript and XML.

Some of the unique features of Ajax are :

• Highly interactive user interface
• Effective communication
• Investment protection of web standard
• Smooth integration with other web content
• No cost involved in administration of web client

The Zimbra Ajax client is a wide ranging user interface, programmed in JavaScript. The client follows Model- View-Controller (MVC) architecture, where changes are rendered in the UI and are then either sent to or retrieved from the backing server. Certain optimization techniques that are a must to enhance the user experience and to reduce latency include aggregating multiple JavaScript and CSS files, compressing the result and browser caching of code.

Client/server communications

A Zimbra messaging and collaboration service includes sending emails and scheduling meetings from any web service enabled application. With it also comes a “fast path” alternative where Zimbra server sends optimized representation which is better suited for processing within the Ajax client.

Figure i: Front-End Architecture

As depicted in Figure i, Zimbra Suite is compatible with a wide array ofclients like Apple Desktop, Outlook, Mozilla Thunderbird etc., using the plug ins provided by Zimbra.

• Outlook (MAPI) – Zimbra includes a MAPI provider plug-in (packaged as a universal Windows Installer or MSI file) that directly links with Outlook and hence must be installed upon the Windows client. This is the Microsoft- sanctioned and supported approach for synchronizing Outlook features like email as well as calendaring and contacts (not supported by IMAP) with messaging servers like ZCS. The Zimbra MAPI provider speaks the identical secure web services protocol as the Zimbra Ajax client (minus the JSON optimization). The Zimbra MAPI provider supports cached mode for efficient disconnected operation and resynchronization. Since it natively supports SSL/TLS and does not require a VPN to be secured over public network.
• Apple Desktop (iSync) – The Zimbra Collaboration Server sync for Apple has been designed on similar lines to the server for Outlook. The added advantage here is that it provides synchronization from Apple Address Book, iCal and Apple Mail.
• Novell Evolution – The Zimbra Collaboration Server for Novell Evolution uses the Evolution Data Server (EDS) as its client- side integration point and provides synchronization via web services transport which is fully secure.
• POP3 – SSL/TLS or clear text transport. Underlying asynchronous I/O implementation ensures efficient handling of many concurrent clients.
• IMAP4 – Most of the IMAP4 extensions are supported by Zimbra.
• iCalendar – Zimbra is fully up-to-date with the emerging Internet calendaring standard for scheduling events and tasks in the following RFCs :
  
  RFC 2445 - Internet Calendaring and Scheduling Core Object
  Specification (iCalendar)
  RFC 2446 - iCalendar Transport-Independent
  Interoperability Protocol (iTIP)
  RFC 2447 - iMIP (iTIP over MIME)
  
  Zimbra also publishes calendar data for read-only access from clients like Apple iCal.
• RSS, REST & SOAP – Zimbra functions are published on suitable XML endpoints for other applications to leverage.
• “Over the Air” Synchronization to Mobile Devices – Zimbra’s smart phones provide Personal Information Management (PIM) software. Zimbra Mobile is capable of synchronizing contacts, appointments, and email with Nokia, Motorola, Samsung, Treo, and Blackberry smart phones. Now applications can easily be extended to mobile devices via Zimbra Collaboration Service, for example exporting customer contacts from the CRM system, sending an email request to visit a particular URL from the browser.