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Question

MultiCast or UniCast

  • March 8, 2011
  • 2 replies
  • 14 views
A
  • Anonymous

Happy Tuesday Folks!

We are having some real slow copies and imaging from our NetBoot Server and our Applications Image server in our network. We can copy to these two server in about 1/10th the time as it takes to copy from them.

We have our network guys looking into this, but I am trying to find out if 10.6 server is using MultiCast by default or is UniCast? At one point years ago, everything was UniCast but since we have upgraded finally, it feels like something is missing.

Any thoughts?

Mick

    2 replies

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    • Bukira
    • Contributor
    • March 8, 2011

    Will be unicast, u have to force multicast

    U need more network bandwidth

    Criss Myers

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    • daworley
    • Valued Contributor
    • March 8, 2011

    Your Casper Admin will be able to tell you if the policy is going to unicast or multicast the image.

    One easily missed step in imaging in regards to Multicasting vs Unicasting is how the image is scanned in asr. Check out the man page for asr, specifically the --nostream section.

    The default in Disk Utility is to apply the --nostream option, making the bit ordering optimized for unicasting. The default in calling asr from Terminal is to not apply --nostream, making the bit ordering optimized for multicasting. Either way, so long as the image is scanned the imaging process will work. If it is scanned wrong, it will still work but will take longer. I don't know if this is exactly what's causing your issue, but it might be a factor.

    Question to the JAMFers: Do the Casper tools automatically rescan the image if a policy wants to deploy the .dmg differently than how the image was scanned for asr?

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