ISC2 Exam SSCP Topic 7 Question 60 Discussion

ARP interrogates the network by sending out a broadcast seeking a network node that has a specific IP address, and asks it to reply with its hardware address. A broadcast message is sent to everyone whether or not the message was requested. A traditional unicast is a 'one-to-one' or 'narrowcast' message. A multicast is a 'one-to-many' message that is traditionally only sent to those machine that requested the information. Semicast is an imposter answer.

Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, 2001, John Wiley & Sons, Page 87.