ASP.NET and IIS request routing module updated to version 3.0

Building scaled web applications with ASP.NET and IIS is not trivial, but not very difficult either. One of the main ways to build scalable web applications is to have more than one web server handle the load. However, if you must keep two or more servers behind a single public DNS name (such as myapp.company.com), you must start thinking about the possible solution options.

One solution in the Microsoft land is to have a front-end server that uses IIS and the Application Request Routing (ARR) module.

This module makes the decisions on where to route requests, and uses a cookie called "ARRAffinity", so that it know to which server a client's request should be routed, based on the original routing decision. Put another way, this means that ARR by default routes client's request always to the same server unless that becomes unavailable. This is called session affinity.

Version 3.0 of ARR has recently been made available, and new features include URL health monitoring, Web Socket support (cool!) and opt-out possibility from session affinity.

You can download your copy from Microsoft's IIS.net web site.