TechContrarian

The information listed below has been tested using Microsoft SQL Server 2005 and Microsoft SQL Server 2008.
Office Communications Server 2007 Enterprise Edition R2 supports the use of non default TCP\IP port configurations for network access to its pool configuration databases that are located on the backend SQL server instance. Microsoft SQL Server supports three types of configurations for the Instances that it can host. They are:
Default Instance
The Default Instance is the instance that is installed on the SQL Server that will inherit the host name of the server that SQL Server is installed on. There can only be one Default Instance installation per SQL Server. So any instances that are installed before or after the single Default Instance will have to be a SQL Server Named Instance.
Named Instance
A Named Instance can be installed onto a SQL Server at any time. Microsoft SQL Server can support many Named Instances at one [...]