Cisco CCNA mock exam questions sample test – Question 47

.With the following equipment list, which of the following network scenarios could be supported?

Two IP subnets of 255.255.255.0
Seven 48-port switches
Two router interfaces

A. 300 workstations in a single broadcast domain, each workstation in its own collision domain
B. 300 workstations, with 150 workstations in two broadcast domains and each workstation in its own collision domain
C. 300 workstations, with 150 workstations in two broadcast domains and all workstations in the same collision domain
D. 600 workstations, with 300 workstations in two broadcast domains and each workstation in its own collision domain

Correct Answer: B

Explanation:
This equipment will support 300 workstations, with 150 workstations divided in two broadcast domains and each workstation in its own collision domain. Subnets with a 24-bit mask (255.255.255.0) yield 254 addresses in each network, so 150 is within those limits. Also, seven 48-port switches make 336 ports available. After subtracting out 2 ports per switch for connecting the switches to each other and the router ( a total of 14) that leaves 321 ports yielding 160 for each subnet ( with one left over) . Two subnets require two router interfaces,
which are available in the scenario, and since switches are in use, each switch port is its own collision domain.

This equipment will not support 300 workstations in a single broadcast domain with each workstation in its own collision domain. With a 24-bit mask, 300 workstations cannot be placed in a single subnet.
This equipment will not support 300 workstations, 150 each in two broadcast domains and all workstations in the same collision domain. The 300 workstations cannot be placed in the same collision domain when using switches. If hubs were in use that would be possible, but not desirable.

This equipment will not support 600 workstations, 300 each in two broadcast domains; each workstation in its own collision domain. 600 workstations cannot be placed in two subnets when using the mask 255.255.255.0. Each subnet can only hold 254 workstations, not 300. Moreover, 300 workstations cannot be placed in the same collision domain when using switches. If hubs were in use that would be possible but not desirable.

Objective:
Network Fundamentals
Sub-Objective:
Describe the impact of infrastructure components in an enterprise network
References:
Cisco Documentation > Internetwork Design Guide > Internetworking Basics