New WAS v7.0 SIP Function

In our last major release of WebSphere Application Server (WAS), we released our Session Initiation Protocol (SIP) functionality. If you need more background on that, you can read this article on developerWorks or check out this presentation to a WebSphere Users Group. In v7.0, we added several pieces of function and further increased our performance.

First, we added support for the following RFCs:

• 3263 - Locating SIP Servers
  
• 3311 - The SIP Update method
  
• 3325 - Private Extensions to the Session Initiation Protocol (SIP) for Asserted Identity within Trusted Networks
  
• 3891 - The SIP Replaces Header
  
• 3911 - The SIP Join Header
  
• 4475 - SIP Torture Test Messages
  

In WAS v6.1, we had supported RFC 3263 aside from section 5 but completed section 5 in this release. The final RFC there, the SIP torture test messages, refers more to a testing effort than function. This torture testing combined with our already rigorous telco carrier grade testing will help WAS v7.0 be one of the most stabile SIP application servers on the market.

Beyond the additional standards support, our SIP Proxy which fronts the application server had several enhancements. It can now support DMZ deployments as discussed here, clustering of the proxy servers when behind the firewall, and an improved load balancing to further reduce call loss in some error conditions associated with retransmissions. Finally, also in our converged Servlet Container, users will notice that the digest authentication support has been made much better.