A. encryption—scrambles the packet contents to prevent them from being seen by unauthorized sources
B. password—a password （community string） sent in clear text between a manager and agent for added protection
C. authentication—determines that the message is from a valid source
D. message integrity—ensures that a packet has not been tampered with while it was in transit 
E. user—to determine if user authentication is used instead of community strings

A. Join interface is a Layer 3 entity， and with the Cisco NX-OS release 6.0， it can only be defined as a physical interface， physical subinterface， Layer 3 port channel， or Layer 3 port channel subinterface.
B. A single join interface can be defined and associated with a given OTV overlay.
C. Multiple overlays can also share the same join interface.
D. Join interface can be a loopback interface.
E. The join interface is a Layer 3 entity that can be defined as a physical interface but not as a logical one.