Synthetic monitoring is an active Web site monitoring that is done using Web browser emulation or scripted real Web browsers. Behavioral scripts (or paths) are created to simulate an action or path that a customer or end-user would take on a site. Those paths are then continuously monitored at specified intervals for availability and response time measures. Synthetic monitoring is valuable because it enables a Webmaster to identify problems and determine if his Web site or Web application is slow or experiencing downtime before that problem affects actual end-users or customers. Answer: B is incorrect. Passive monitoring is a technique used to analyze network traffic by capturing traffic from a network by generating a copy of that traffic. It is done with the help of a span port, mirror port, or network tap. Once the data (a stream of frames or packets) has been extracted, it can be used in many ways. Passive monitoring can be very helpful in troubleshooting performance problems once they have occurred. Passive monitoring relies on actual inbound Web traffic to take measurements, so problems can only be discovered after they have occurred. Answer: A is incorrect. Route analytics is an emerging network monitoring technology specifically developed to analyze the routing protocols and structures in meshed IP networks. Their main mode of operation is to passively listen to the Layer 3 routing protocol exchanges between routers for the purposes of network discovery, mapping, real-time monitoring, and routing diagnostics. Answer: C is incorrect. Network tomography is an important area of network measurement that deals with monitoring the health of various links in a network using end-to-end probes sent by agents located at vantage points in the network/Internet.