Load Balancing and Session Broker in Windows Server 2008 Terminal Services
The Terminal Services Session Broker is not a new idea in Windows Server 2008, but there have been some significant security and performance improvements over the previous version in Windows Server 2003. The Microsoft Terminal Services team has a blog post explaining some of the new improvements.
In a Windows Server 2003 Terminal Services environment, “when a terminal server in a farm received a connection request, it created a temporary session to authenticate the user and load user policies. If no local disconnected session was present, it queried the TS Session Broker to see if there was a disconnected session for the user on another machine in the SB farm. If a disconnected session was found, a redirection request was sent to the client to connect to the other server instead. The temporary session was then discarded.
The temporary session creation resulted in significant delay in completing the connection because a full logon occurs in the session. Also, the user experience was unpleasant because the user saw two welcome screens, first for the temporary session and then again for the redirected session.”
So, that is the way it used to work. Windows Server 2008 builds on the Session Broker by adding load balancing and adding security enhancements using CresSSP (which also gets rid of that nasty double login - which increases logon performance). “In Windows Server® 2008, a new load balancing algorithm has been introduced to distribute the load amongst all the servers in the farm… The new technique uses the credentials (user name and domain name) provided by CredSSP and the initial program available at that point, to load the user profile. It then uses the same credential to query for a disconnected session in the SB farm, if the machine is in a farm. If a disconnected session is found on another machine in the farm, it immediately sends a redirect packet to the client and the client subsequently connects to the redirected server. Hence no temporary session is created before the connection is redirected.”
To learn more about CredSSP, check out how RDP Frontside Authentication works.
Technorati : Load Balancing, Session Broker, Terminal Services, Windows Server 2008
Del.icio.us : Load Balancing, Session Broker, Terminal Services, Windows Server 2008
Ice Rocket : Load Balancing, Session Broker, Terminal Services, Windows Server 2008