If I understand you correctly, your clients from different regions are connecting to a single GUP while you want them to connect to their respective local GUPs.
I assume you are using the "Multiple GUP" feature (the missing registry key indicates this). This feature may cause unexpected behavior. If all GUPs defined in the Multiple GUP list are in the same subnet, the clients will connect to the same GUP in most cases. Best explained here:
http://www.symantec.com/docs/TECH139867
The easiest way to solve the problem is to create a group structure reflecting your regions. In every LiveUpdate policy of these groups, set a different Single GUP.
To your questions:
1) On GUP server i see "MasterClientHost" Value data as empty. What will confirm that this is an active GUP server ?
If MasterClientHost is empty, it may indicate you are using the multiple GUP feature. See link above. Active GUPs are listening on port 2967 (check with netstat) and have a cache folder (in SEP 11: <Drive>:\Program Files\Symantec\SharedUpdates).
2) What will confirm that the clients have started taking updates from GUP server ?
See John Q.'s posting below. Unfortunately I don't know if it works on SEP 11 as well:
https://www-secure.symantec.com/connect/articles/how-can-we-check-which-content-sep-121-clients-are-downloading-gup
Alternatively, in the local Client system log you should find "Download content from GUP". Or you enable sylink debugging on clients:
http://www.symantec.com/docs/TECH97190
3) I have recently saw an increase in dispace, i know this is due the client packages are being downloaded tp SPEM, still what do u suggest is there a need to increase the disk space, we have 35GB HDD attached to it
The client packages are not the biggest issue. Old packages can be deleted. However, try to save as many content revisions as possible to prevent full downloads (~270 MB). My personal rule of thumb for the size of one single revision is as follows:
(270 MB + (1.9 x 270 MB)) x 2
The zipped 270 MB packet will be unzipped on the SEPM (cannot be prevented), that's the 1.9 factor. And you have to double the result because SEPM will produce 32-bit and 64-bit content revisions. Of course you have to consider that these 270 MB are steadily growing. In a year they may be 350 MB.
4) Is 2MB bandwith okay as i have also told you about our whole scenario ?
Which connection has 2 Mbit/s in your environment? If, say, the SEPM is in Manassas and all regions have a maximum of 2 Mbit/s to this SEPM it may be ok if you save enough content revisions on your SEPM. If your GUP scenario is working, it should be enough because full downloads are seldom. BTW, you can throttle the bandwidth in the GUP settings.
5) When does TCP port 2967 becomes active, do u have any videos ?
Se 1). No other videos, as far as I know; keep in mind that the videos mentioned in my post above are for SEP 11 only. When you'll upgrade to 12.1, you will face a slightly different GUP behavior and extended features.
To check GUP and download behavior, you could try the (unsupported) SEP Content Distribution Monitor:
https://www-secure.symantec.com/connect/downloads/sep-content-distribution-monitor