CCDA Certification Interview Question:

Suppose A Cisco security mechanism has the following attributes:
it is a sensor appliance
it searches for potential attacks by capturing and analyzing traffic
it is a "purpose-built device"
it is installed passively
it introduces no delay or overhead
Which Cisco security mechanism is this?
A. IKE
B. PIX
C. HIPS
D. NIDS
E. HMAC