Alcatel Unleashed

does 7750 SR support active intercept using SNMPv3 . has any one know about MIBs that support Lawful .
what is necessary configuration end to enable LI.

Take a look at the section "Lawful Intercept Configuration Overview" in the 7750 SR OAM and Diagnostics Guide.

You can also see which SNMP subtrees are needed in the output of "show system security view li-view"