Certification Question of the Day [QOTD] for Cisco CCNA [CCNA 640-802] [Q001 CCNA] [ANSWER]

QUESTION – What is a router’s primary function on a network? (Choose all that apply – choose only the best answers).

A.   Create the boundary of a Broadcast domain

B.   Create the boundary of a Collision domain

C.   Creates a network segment where it is the default gateway

D.   Creates a network segment where it is the central network device on that segment

E.   Responsible for Packet Switching on the network

F.   Responsible for Path Selection on a network

Answer and Explanation.

The best answers for this question are A, C, E and F

Choice A - Create the boundary of a Broadcast domain, is correct because routers are mainly responsible for creating the logical network division that we call a broadcast domain. For more information please see the Wikipedia article titled “Broadcast Domain”.

Choice C - Creates a network segment where it is the default gateway, is a correct answer because routers are generally the default gateways for a network segment. For more information please see the “Act as the Default Gateway” segment of the article posted on the InetDaemon website titled “What Is A Router?”

Choices E and F are also correct in that a router is mainly responsible for both packet switching and path selection on a network. For more information please see the Wikipedia articles titled “Router,” “Packet switching” and “Routing”

 

Choice B - Create the boundary of a Collision domain, is technically correct but it is not the best answer which is why it is not considered as a choice for this question. Network connected devices that are connected to the same Ethernet repeater or switch are considered to be members of the same broadcast domain. When you are talking about the true division point of a Collision Domain that would be one of the primary functions of a network switch. For more information please see the Wikipedia article titled “Broadcast Domain”.

Choice D - Creates a network segment where it is the central network device on that segment, is not a correct answer. While it is entirely possible that a router could be the central network device it often is an end point. Having a default gateway where all traffic enters and exits often places the device on the extreme end of a network segment. Generally hubs and more often than not, switches, are the devices you will see as central network devices for a given segment.