what all i need to monitor on my network devices for pro active monitoring...
like cpu utilizations, connecitivity, and what else all???
what features i need to add in my console of network management system,, or what features i need to see before purchasing or going for some network managements system of my network devices???
This is a very broad question. Most of the times, what you monitor will depend on the requirements. From my past experience, I would recommend monitoring at least these parameters: 1) CPU usage 2) Memory usage 3) Connectivity between sites/servers and corresponding latency <<<<< can be achieved using ping 4) Send your log messages to the syslog server. Parse there for anything above warning or error level. You might want to monitor for some specific logs that are dependent on your requirements/deployment. 5) Monitor the interface traffic (especially for the uplinks). 6) Monitor the size of your routing/ethernet-switching tables.
One of the best things that you can do for your deployment is to figure out the patterns when everything is 'normal'. That way, if something goes bad, you can compare the data and reach the solution quickly.
About the features for the NMS: again depends on your requirements I would make a list of all the attributes that are very important for my network and corresponding SLAs and then start looking for those features in the softwares which are available.
Those are pretty broad questions and so difficult to answer. Can you tell us a little about the size of your network, it's purpose, and your experience with other monitoring solutions?
BTW, with a Juniper Care support contract, you are entitled to use Junos Space and Service Now applications - for free (for the virtual machine version). Junos Space comes with built-in fault and performance monitoring that is pre-configured for most common uses. This would at least provide you a benchmark to compare against other solutions. See http://www.juniper.net/customers/support/?space2 for more info.