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MDT 2013 Multicast not working RRS feed

  • Question

  • After enabling this, all the workstations show status of "waiting" in MDT and never start applying the OS.  I had to manually switch them all to unicast to get them to image.

    When I deployed a single system, it successfully deployed with multicast enabled, but the OS installed very, very slowly (maybe 5 times slower than normal).  When I tried to do multiple at the same time, it never even started deploying the OS.

    I looked in the MDT deployment documentation and saw this:

    "MDT supports only the multicast transfer of images stored in the LTI$ distribution share. Images stored in Windows Deployment Services cannot be deployed using multicast transfer"

    I don't see any share on the deployment server named "LTI$."  How does that get created?  Do I have to manually rename a share to LTI$ to make this work? 


    • Edited by MyGposts Friday, August 12, 2016 3:55 PM
    Friday, August 12, 2016 3:53 PM

All replies

  • If one machine works with multicast many should work.  Since this is really a WDS question the host OS version would be very useful.

    Are you PXE booting?


    Many questions such as where do I find logs and what logs are interesting are found in: MDT TechNet Forum - FAQ & Getting Started Guide Please take the time to read it. Also if you don't post logs your problem won't be easily solved.


    Friday, August 12, 2016 5:59 PM
    Moderator
  • Yes, it is PXE boot and the PXE boot part of it works.

    When deploying a single system via multicast, it was so slow that we would never want to do that again.

    The WDS server is 2012 R2.

    I noticed the MDT documentation says there has to be a deployment share named LT1$ for multicast to work.

    So, everyone who uses multicast has to rename their deployment share to LTI$ if they want to use multicast?

    Since there can only be on share with a specific share name, that would mean that if you have multiple deployment shares on your server, you can only use multicast from one of them?

    Friday, August 12, 2016 6:11 PM

  • Yes multicast is slower for 1 machine.  Multicast is useful for 1 to many installs.  Since you already decided it is too slow for a single machine are you moving forward (although I suppose you could mess with the TFTP block size and see if you can get better performance).

    You might get something useful out of the WDS logs. https://support.microsoft.com/en-us/kb/936625

    The other thing is it might be a network issue.  You will probably need to look at your end to end scenario and look at each part.


    Many questions such as where do I find logs and what logs are interesting are found in: MDT TechNet Forum - FAQ & Getting Started Guide Please take the time to read it. Also if you don't post logs your problem won't be easily solved.

    Friday, August 12, 2016 6:26 PM
    Moderator
  • Normally, we will be deploying more than one machine at a time.  This main issue is that when I tried to do 5 at a time, it never launched.  They all stayed in a waiting state when unicast is enabled.

    Is the LTI$ share name issue something that needs to be fixed?

    Friday, August 12, 2016 6:31 PM
  • No it doesn't matter about LT1$.  BTW what documentation says that?  Is it a tutorial of some sort?

    Back to troubleshooting If 1 worked then many should work.  So use the link I sent to take a look at the WDS logging. Since they are all PXE booting there will be log entries for them.  When you find something interesting in the log take a look at your favorite search engine and let us know what you find.


    Many questions such as where do I find logs and what logs are interesting are found in: MDT TechNet Forum - FAQ & Getting Started Guide Please take the time to read it. Also if you don't post logs your problem won't be easily solved.

    Friday, August 12, 2016 6:37 PM
    Moderator
  • No it doesn't matter about LT1$.  BTW what documentation says that?  Is it a tutorial of some sort?


    No.  The official documentation from Microsoft says that.

    https://technet.microsoft.com/en-us/library/dn759415.aspx

    Friday, August 12, 2016 9:43 PM
  • I think you missed the context of the LTI$:

    For LTI deployments, the Deployment Workbench creates a multicast namespace for the deployment share.

    Have you taken any time to look at the WDS logs?


    Many questions such as where do I find logs and what logs are interesting are found in: MDT TechNet Forum - FAQ & Getting Started Guide Please take the time to read it. Also if you don't post logs your problem won't be easily solved.

    Friday, August 12, 2016 9:49 PM
    Moderator
  • I think you missed the context of the LTI$:

    For LTI deployments, the Deployment Workbench creates a multicast namespace for the deployment share.

    Have you taken any time to look at the WDS logs?


    Many questions such as where do I find logs and what logs are interesting are found in: MDT TechNet Forum - FAQ & Getting Started Guide Please take the time to read it. Also if you don't post logs your problem won't be easily solved.

    If that's not what they meant, this quote is not worded very well.

    "MDT supports only the multicast transfer of images stored in the LTI$ distribution share. "

    Why not just call it the MDT deployment share instead of LTI$?

    I will not be able to get to the MDT server again until Monday.

    I also found this post here where they claimed their issue was solved be renaming their deployment share to LTI$

    https://social.technet.microsoft.com/Forums/en-US/3e61a8f4-9908-4d3c-8c02-f4b95c9aa447/mdt-2013-wds-server-2012-r2-multicasting-not-working-rc-1073740940?forum=mdt

    "Thanks for all the help.  We found what the issue was.  It turns out that the MDT Deploymentshare needs to be shared with the name LTI$  We had it shared as just Deploymentshare.  After making that change multicast is working great.

    Hope this helps anyone else with this problem."


    • Edited by MyGposts Friday, August 12, 2016 10:04 PM
    Friday, August 12, 2016 10:02 PM
  • Until we look at your WDS log this is just guessing.  I have never had a share named LTI$ however I have had multicast work so it isn't that.

    Many questions such as where do I find logs and what logs are interesting are found in: MDT TechNet Forum - FAQ & Getting Started Guide Please take the time to read it. Also if you don't post logs your problem won't be easily solved.

    Friday, August 12, 2016 10:27 PM
    Moderator
  • What error am I'm looking for and in which one of the log files?

    Can the workstations be plugged into a regular dumb switch or do they need their network cables plugged directly into a managed  switch that specifically supports multicast?
    Monday, August 15, 2016 11:21 PM
  • I don't know what  your WDS logs will say.  Look and let me know what you find.

    As far as a network hub versus a switch goes a hub should work fine since there is no routing required.


    Many questions such as where do I find logs and what logs are interesting are found in: MDT TechNet Forum - FAQ & Getting Started Guide Please take the time to read it. Also if you don't post logs your problem won't be easily solved.

    Tuesday, August 16, 2016 12:22 AM
    Moderator
  • These are the only things I see in logs that looks like errors:

    [WDSServer/WDSMC] WDSMCTP[0xc1afcd15] No window space to send; WindowSize=2, InFlight=39, Recover=1

    [WDSServer/WDSMC] Holding off window expansion until repairs are complete. McTrail#=6110, Lead=6149

    [WDSServer] [base\eco\wds\wdsmgmt\src\wdsdirectoryservicesusepolicy.cpp:295] Expression: , Win32 Error=0x2

    None of the systems will start installing the OS, they all say "Attempting multicast transfer"

    Tuesday, August 16, 2016 4:45 PM
  • Do boot images need to be changed for multicast?
    Tuesday, August 16, 2016 4:50 PM
  • So you configured tracing and did your failing scenario again and that is all that showed in the logs?

    If there is something about you boot images that changed you might need to change them.


    Many questions such as where do I find logs and what logs are interesting are found in: MDT TechNet Forum - FAQ & Getting Started Guide Please take the time to read it. Also if you don't post logs your problem won't be easily solved.

    Tuesday, August 16, 2016 5:02 PM
    Moderator
  • The boot image is the same as it has always has been and it boots up to the MDT deployment wizard fine.  We have always just used unicast.  Do we have to use different boot images for unicast vs multicast?

    We are trying multicast for the first time now.

    Tuesday, August 16, 2016 5:08 PM
  • You may want to contact premier support.

    Many questions such as where do I find logs and what logs are interesting are found in: MDT TechNet Forum - FAQ & Getting Started Guide Please take the time to read it. Also if you don't post logs your problem won't be easily solved.

    Tuesday, August 16, 2016 5:16 PM
    Moderator