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1. Get the windows box client to recognise the Linux machine's Simple CA for getting the certificates ? ( will I have to hack thru the python scripts ? or some option is available )

I'm not sure what you mean by recognizing the simple ca for certs. If you're issuing your own certs with a globus simple ca, you're going to have to import the CA certificate into any machines that you're going to use with those certs, as well as importing the users' identity certs.

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2. Get the WIndows machine to be multicast enabled : Do you know of some reliable softwatre , or are there any settings that you know of ?

Like Jennifer said, this is a network issue; you shouldn't have to do anything on the win box to make it understand multicast (well, usually - if you have multiple network interfaces, or are using something like VMware that installs additional interfaces, there is some tweaking that you may have to do).

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3. Initaially , I had setup the gpt3.0 on both the machines and had planend to get the grid up and running and then put up the AG on top of it. But when i have proceeded to the AG installation , the package has GPT1.0 ( with linux AG distribution ) and GPT2.0 ( with win2k AG dist.) . Will the "downgrading" of gpt have any problems ?

I'm not sure what you're referring to with respect to GPT2.0 on the win2k distribution; we aren't using GPT there (GPT being the Globus Packing Technology stuff). On the linux side, I'm not sure if the later GPT versions are backward compatible with the older Globus we require. --bob