Network Load Balancing Improvements

Applies To: Windows Server 2008

In the Windows Server® 2008 operating system, the improvements to Network Load Balancing (NLB) include support for Internet Protocol version 6 (IPv6) and Network Driver Interface Specification (NDIS) 6.0, Windows Management Instrumentation (WMI) enhancements, and improved functionality with Forefront Threat Management Gateway 2010 Enterprise Edition and Forefront TMG 2010 Enterprise Edition.

What does Network Load Balancing do?

NLB is a feature that distributes the load for networked client/server applications across multiple cluster servers. It is part of the Windows scale out functionality and is one of three Windows Clustering technologies.

Who will be interested in this feature?

NLB is used by IT professionals who need to distribute client requests across a set of servers. It is particularly useful for ensuring that stateless applications, such as a Web server running Internet Information Services (IIS), can be scaled out by adding additional servers as the load increases. NLB provides scalability by allowing you to easily replace a malfunctioning server or add a new server.

Are there any special considerations?

You must be a member of the Administrators group on the host that you are configuring by using NLB, or you must have been delegated the appropriate authority.

What new functionality does this feature provide?

NLB includes the following improvements:

  • Support for IPv6. NLB fully supports IPv6 for all communication.

  • Support for NDIS 6.0. The NLB driver has been completely rewritten to use the new NDIS 6.0 lightweight filter model. NDIS 6.0 retains backward compatibility with earlier NDIS versions. Improvements in the design of NDIS 6.0 include enhanced driver performance and scalability and a simplified NDIS driver model.

  • WMI Enhancements. The WMI enhancements to the MicrosoftNLB namespace are for IPv6 and multiple dedicated IP address support.

    • Classes in the MicrosoftNLB namespace support IPv6 addresses (in addition to IPv4 addresses).

    • The MicrosoftNLB_NodeSetting class supports multiple dedicated IP addresses by specifying them in DedicatedIPAddresses and DedicatedNetMasks.

  • Enhanced functionality with Forefront Threat Management Gateway 2010 Enterprise Edition and Forefront TMG 2010 Enterprise Edition. With Forefront Threat Management Gateway and Forefront TMG, you can configure multiple dedicated IP addresses per each NLB node. They also provide NLB with SYN attack and timer starvation notifications (these scenarios typically occur when a computer is overloaded or is being infected by an Internet virus).

  • Support for multiple dedicated IP addresses per node. NLB fully supports defining more than one dedicated IP address per node. (Previously only one dedicated IP address per node was supported.)