Scalability

Redundancy

Supports a combination of up to 24 web and database servers in a farm.
 Servers can be added or removed as needed without service interruption.
Eliminates single point of failure.
Failed servers removed automatically. The remaining servers handle client requests.

Load Balancing

Manageability

Persistent session control maintains client session on the same web server for the duration of the session.
Distributes requests to servers based on real-time availability and load.
Automatic load re-distribution when servers are added or removed.
.Net Framework Remoting load balancing. 
Single Internet Information Server (IIS) management point  for all servers.
Single content repository and content propagation.
Virtual Web Servers across single or multiple IP addresses.
May be combined with MS SQL database failover cluster for total front/back end solution.

Distribute load across a group of front-end independent web servers managed centrally