WDS Multicasting MDT 2010 created SOE

Question

I'm just wondering if the following scenario is possible with the setup we currently have.  The architecture we've implemented is:
MDT 2010 on Win2008 R2.  No clients build from this server.
Windows 2008 R2 servers with the WDS Transport Server role only.  We have no AD in the environment, so this is what I'm limited to.  Clients connect via PXE to these servers to image, using a WinPE LTI.
Multicast has been setup and configured, and it working successfully for the base OS .wim file only.  Once the client moves further into the task sequence and begins installing additional applications, their traffic falls back to Unicast.
Is it possible to maintain multicast throughout the entire imaging process given this environment and its limitations?

Answer 1

Interesting setup.  I think the answer is no.  My thought process is:
- Boot LiteTouch wim via PXE - unicast for multiple machines
- multiple machines establish a session from which the deployment server starts sending out the blocks for the install.wim via multicast to clients at the same time.
- task sequence starts up at different times for the clients for first boot\OOBE and complete final tasks via unicast.
Once the install.wim is deployed, that piece is complete from multicast perspective.  This would happen if you had a domain, so I don't think you environment piece is a factor.  By the way, you may want to evaluate Windows Server 2012 as it supports
WDS with non domain joined configuration called "stand alone".
Configure Windows Deployment Services (WDS) In Standalone Mode in Windows Server 2012
http://technet.microsoft.com/en-us/video/configure-windows-deployment-services-wds-in-standalone-mode-in-windows-server-2012.aspx
If I recall multicast is actually slower than unicast unless the number of deployments you have going concurrently are quite high.  This is the best link that I know of that shows the speeds based on deployment type:
Optimizing Performance and Scalability
http://technet.microsoft.com/en-us/library/cc732088(v=WS.10).aspx
Dave Guenthner [MSFT] This posting is provided "AS IS" with no warranties, and confers no rights. http://blogs.technet.com/b/davguents_blog
I concur with Dave's post.
It's not a limitation of your environment, however multicast is only supported for data images. Once the OS is actually deployed, and the task sequence continues within Windows, all network traffic will be unicast as it will only access the deployment share
through smb.
The 'general' cutoff as to where multicast will become more effective vs unicast in terms of computers starts at about 50, more then 50 unicast connections at the same time will generally cause the wds server not being able to keep up to serve the data.
This still depends on the server's hardware, unless it's a really high end machine with fast storage you might be able to serve more then 50 unicast at a reasonable speed.
Kind regards,
Stephan Schwarz
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