CCENT Concepts Pt. 5

Question 1

TCP/IP Transport Layer Feature -

Multiplexing using ports

Answer 1

Function that allows receiving hosts to
choose the correct application for
which the data is destined, based on
the port number

Question 2

TCP/IP Transport Layer Feature -

Error recovery

Answer 2

Process of numbering and
acknowledging data with Sequence
and Acknowledgement header fields.

Question 3

TCP/IP Transport Layer Feature -

Flow control using windowing

Answer 3

Process that uses window sizes to
protect buffer space and routing
devices.
page

Question 4

TCP/IP Transport Layer Feature -
Connection establishment and
termination

Answer 4

Process used to initialize port
numbers and Sequence and
Acknowledgment fields.

Question 5

TCP/IP Transport Layer Feature -
Ordered data transfer and data
segmentation

Answer 5

Continuous stream of bytes from an upper-layer
process that is “segment” for transmission and
delivered to upper-layer processes at the receiving
device, with the bytes in the same order.

Question 6

FTP Port Number

Answer 6

20 (data) & 21 (control)

Question 7

SSH Port Number

Answer 7

22

Question 8

Telnet Port Number

Answer 8

23

Question 9

SMTP Port Number

Answer 9

25 TCP

Question 10

DNS Port Number

Answer 10

UDP, TCP 53

Question 11

DHCP Port Number

Answer 11

UDP 67,68

Question 12

TFTP Port Number

Answer 12

UDP 69

Question 13

HTTP (WWW) Port Number

Answer 13

TCP 80

Question 14

POP3 Port Number

Answer 14

TCP 110

Question 15

SNMP Port Number

Answer 15

UDP 161

Question 16

SSL Port Number

Answer 16

TCP 443

Question 17

RTP-based Voice (VoiP) and

Video

Answer 17

UDP, 16, 384 - 32, 767

Question 18

Connection-oriented protocol

Answer 18

A protocol that requires an exchange an exchange
of message before data transfer begins or that has
a required preestablished correlation between two
endpoints.

Question 19

Connectionless protocol

Answer 19

A protocol that does not require an
exchange of messages and that does
not require a preestablished correlation
between two endpoints.

Question 20

Low Delay

Answer 20

VoiP requires a very low delay between the sending phone and the receiving
phone - typically less than 200 milliseconds (.2 seconds). This is a much lower
delay than what is required by typical data applications.

Question 21

Low Jitter

Answer 21

Jitter is the variation in delay. VoiP requires very low jitter as well, whereas
data applications can tolerate much higher jitter. For example, the jitter for
consecutive VoIP packets should not exceed (.03 seconds), or the quality
degrades.

Question 22

Loss

Answer 22

if a VoIP packet is lost in transit because of errors of because a router doesn’t
have room to store the packet while waiting to send it, the VoIP packet is not
delivered across the network. Because of the delay and jitter issues, there is
no need to try to recover the lost packet. It would be useless by the time it was
recovered. Lost packets can sound like a break in the sound of the VoIP call.

Question 23

Denial of Service (DoS)

Answer 23

An attack whose purpose is to break things.

Question 24

Reconnaissance attack

Answer 24

The kind of attack may be disruptive as
a side effect, but its goal is gathering
information to perform an access
attack.

Question 25

Access attacks

Answer 25

An attempt to steal data, typically data
for some financial advantage, for a
competitive advantage with another
company, or even for international

Question 26

Common Security Issues in an

Enterprise

Answer 26

• Access from the wireless LAN
• Infected mobile laptops
• Disgruntled employees

Question 27

anti-x

Answer 27

The term used by Cisco to refer to a
variety of security tools that help
prevent various attacks including
antivirus, anti-phishing, and anti-spam.