hi Ashoka,
Please refer below, also you will get hardware specifiation in below links
http://www.ntop.org/pf_ring/port-mirror-vs-network-tap/
https://www-secure.symantec.com/connect/forums/discussion-recommended-tap-device-dlp-network-monitor#comment-8100021
https://www-secure.symantec.com/connect/forums/network-monitor-install-details