Which four attributes must be considered when designing a secure IP telephony solution? (Choose four.)
A.
protection of voice at Layer 2
B.
placement of application layer gateways
C.
number and sizing of output queue thresholds
D.
stateful inspection of all packets on the corporate intranet
E.
creation and assignment of VU\Ns and broadcast domains
F.
implementation of packet filters and the establishment of firewalls