Altering the Network Library for Visual LANSA V11 SP5 and above

Description:

This technical note raises a number of points with regards to changing the network library and the performance effect to the system. It should be noted that TCP/IP is the default used by the LANSA installation and is suitable for all situations (i.e. no changes are required). However, some customer may choose to change to Named Pipes.

Summary:

• The default for the LANSA installation is TCP/IP
• TCP/IP can be changed to Named Pipes when SQL Server and the client are on the same machine, otherwise TCP/IP should be used
• Named Pipes performs best in a high bandwidth/low latency network, or when the SQL client and server are on the same machine. However, we recommend TCP/IP in all LAN situations as it is at least as fast as Named Pipes and has the most flexibility
• If you are in a situation where you have a laptop that connects to a domain and you have the SQL Server and the client on the same machine then we recommend that you stay with the default TCP/IP configuration. This is due to a known Windows defect that can cause issues with the configuration

Detailed information:

1. In a fast local area network (LAN) environment, TCP/IP and Named Pipes are comparable with regard to performance. However in a slow network environment the overhead of the Named Pipe protocol can have a significant effect on other network clients.
   
   If the Client Application is running on the same PC as the SQL Server then the Named Pipe protocol is very fast (faster than TCP/IP).
   Please refer to http://msdn.microsoft.com/en-us/library/ms187892.aspx
    
2. If the host PC belongs to a network domain, that for some reason is physically outside of that domain, (an example of this is a notebook used from home over a VPN) then the trusted connection to Local SQL Server using the TCP/IP protocol may run into a known Windows problem
    
3. To by-pass the problem in (2) instead of using the PC name to qualify the connection 127.0.0.1 was used. For example PC1\SQLEXPRESS becomes 127.0.0.1\SQLEXPRESS where SQLEXPRESS is the instance name.
    
4. Consideration for Visual LANSA only: Visual LANSA remembers the connection string returned to it. This connection string contains a number of parameters for Named Pipes (if Named Pipe protocol is used). These parameters change when the host PC moves in and out of its domain.
   
   Because of this feature we use TCP/IP as our network library for Visual LANSA on Microsoft SQL Server. Named Pipes can still be used by Visual LANSA in this situation but when the machine is moved the Visual LANSA connection string would need to be erased.