You are the network administrator at CertKing . CertKing has 14 different departments, each of which
requires its own subnet. CertKing has been assigned the network address 155.69.0.0. CertKing does not
expect any one department to exceed maximum of 1,000 hosts but the company does expect that the
number of departments will increase by up to 10 each year for the next four years. You are required to
apply a subnet mask that will meet these requirements, and would not need to be changed for at least 4
years.
What subnet mask will you use?A. 255.255.0.0B. 255.255.240.0C. 255.255.252.0D. 255.255.255.0E. 255.255.255.192Ans: C

Explanation:
We have one Class B address that we must divide.
Currently there are 14 departments. We must make provision for an increase of 10 departments each year. Thus
we need to make provision for 14+(10x4)=54 departments. Each department requires a separate subnet so we
need 54 network addresses.
No one department will exceed 1,000 hosts so we need to support 1,000 hosts per subnet.
The process of extending the default subnet mask creates a counting range in the octet that the subnet was
extended into, which can be used to represent subnetworks. This allows a single Class A, B, or C network to be
subdivided into many smaller groups with each group, or subdivision treated as if it were a network itself. A
Class B address has a default subnet mask of 255.255.0.0. In binary, this is a 16 bit mask
(11111111.11111111.00000000.00000000).
We require 6 host bits from the host id to support 54 subnetworks (26-2=62). This leaves 10 bits for hosts,
which is sufficient as 10 bits supports 1022 hosts (210-2=1022).
We need to add the 6 bits to the default 16 bit mask to give us a 22 bit mask
(11111111.11111111.11111100.00000000). This equates to 255.255.252.0
Reference:
CertKing 640-821 Study Guide, Section 2, "IP Addressing and Subnetting"


Q50
You are a technician at CertKing . Your newly appointed CertKing trainee wants to know what command
she can use to verify the active configuration on a Cisco router.
What would your reply be?A. Router# show memoryB. Router# show startup-configC. Router# show running-configD. Router# show flashAns: C

Explanation:
The two commands that list the currently used configuration in a router is reloaded are show running-config
and write terminal.
Reference:
CCNA Self-Study CCNA INTRO exam certification Guide (Cisco Press, ISBN 1-58720-094-5) page 494


Q51
In the following is the MAC address of your NIC:
C9-3F-32-B4-DC-19
What is the OUI portion expressed in decimal format?A. 172-47-10B. 198-59-21C. 201-63-50D. 204-73-54E. 212-92-64F. 224-96-69Ans: C

Explanation:
The first half of the address identifies the manufacturer of the card. This code, which is assigned to each
manufactory by the IEEE, is called the organizationally unique identifier (OUI). In this example, the OUI is:
C9-3F-32. This equates to 201-63-50.
Reference:
CertKing 640-821 Study Guide, Appendix A "Decimal, Hexadecimal and Binary Conversion Table"


Q52
You are a technician at CertKing . Your newly appointed CertKing trainee wants to know what the binary
value for c9-3f is.
What would your reply be?A. 10010010-00011101B. 10101100-00100110C. 11000011-01101100D. 11001001-00111111E. 11100110-00011101F. 11100111-00001100Ans: D

Explanation:
c9-3f is the hexadecimal equivalent of 201-63 in binary, this is 11001001-00111111


Q53
Which of the following is a basic characteristic of switches and hubs?A. Hubs cannot filter frames.B. Using hubs is costly with regard to bandwidth availability.C. Switches do and can not forward broadcasts.D. Switches are more efficient than hubs in processing frames.E. Switches increase the number of collision domains in the network.Ans: E

Explanation: Switches increases the number of collisions domains in the network.
Note:
Switches use a couple of different types of internal processing variations. Almost of the more recently released
switches use store-and-forward processing, but all three types of switching are supported in at least one type of
currently available Cisco Switch.
o Store-and-forward -The switch fully receives all bits in the frame (store) before forwarding the frame
(forward).
o Cut-through - The switch performs the address table lookup as soon as the destination address field in
the header is received.
o Fragment-free - This performs like cut-through switching, but the switch waits for 64 bytes to be
received before forwarding the first bytes of the outgoing frame.
Reference:
CCNA Self-Study CCNA INTRO exam certification Guide (Cisco Press, ISBN 1-58720-094-5) Page 243