CCENT Concepts Pt. 2

Question 1

CSMA/CD

Answer 1

• A device that wants to send a frame wait until the LAN is silent. In other
  words, no frames are currently being sent. Before attempting to send an
  electrical signal.
• If a collision still occurs, the devices that caused the collision wait a random
  amount of time and then try again.

Question 2

EIA/TIA Standard Ethernet

Cabling Pinouts - T568A

Answer 2

1 - Green/White
2 - Green
3 - Orange/White
4 - Blue
5 - Blue/White

Question 3

EIA/TIA Standard Ethernet

Cabling Pinouts - T568B

Answer 3

1 - Orange/White
2 - Orange
3 - Green/White
4 - Blue
5 - Blue/White

Question 4

Devices that transmit on 1,2 and

Receive on 3,6

Answer 4

PC NICs, Routers, Wireless Access
Point (Ethernet interface), Networked
printers (printers that connected
directly to the LAN)

Question 5

Devices that transmit on 3,6 and

Receive on 1,2

Answer 5

Hubs, Switches

Question 6

Crossover Ethernet Cable

Answer 6

1 - 3
2 - 6
3 - 1
4 - 4
5 - 5

Question 7

CSMA/CD algorithm

Answer 7

Step 1 - A device with a frame to send listens until the Ethernet is not busy.
Step 2 - When the Ethernet is not busy, the sender(s) begin(s) sending the
frame.
Step 3 - The sender(s) listen(s) to make sure that no collision occurred.
Step 4 - If a collision occurs, the devices that had been sending a frame each
send a jamming signal to ensure that all stations recognize the collision.
Step 5 - After the jamming is complete, each sender randomizes a timer and
waits that long before trying to resend the collided frame.

Question 8

Structure of Unicast Ethernet

Addresses

Answer 8

Organizationally Unique Identifier (OUI), Vender
Assigned (NIC Cards, Interfaces)
Size, in bits - 24 Bits, 24 Bits
Size, in hex digits 6 Hex Digits, 6 Hex Digits

Question 9

MAC

Answer 9

Media Access Control, 802.3
(Ethernet) defines the MAC sublayer of
IEEE Ethernet.

Question 10

Ethernet Address, NIC address,

LAN address

Answer 10

Other name often used instead of MAC
address. These terms describe the
6-byte address of the LAN interface
card.

Question 11

Burned-in address

Answer 11

The 6-byte address assigned by

the vendor making the card.

Question 12

Unicast address

Answer 12

An address that means “all
devices that reside on this LAN
right now.”

Question 13

Multicast address

Answer 13

On Ethernet, a multicast address
implies some subset of all devices
currently on the Ethernet LAN.

Question 14

Full-Duplex

Answer 14

Generically, any communication in which two communication devices can
concurrently send and receive data. In Ethernet LANs, the allowance for both
devices to send and receive at the same time, allowed when both devices
disable their CSMA/CD logic.

Question 15

Half-Duplex

Answer 15

Generically, any communication in which only one device at a time can send
data. In Ethernet LANs, the normal result of the CSMA/CD algoritm that
enforces the rule that only one device should send at a time.

Question 16

Hub

Answer 16

A LAN device that provides a centralized connection point for LAN cabling,
repeating any received electrical signal out all other ports, thereby creating a
logical bus. Hubs do not interpret the electrical signals as a frame of bits, so
hubs are considered to be Layer 1 devices.
page 5

Question 17

Pinout

Answer 17

The documentation and
implementation of which wires inside a
cable connect to each pin position in
any connector.

Question 18

Protocol Type Field

Answer 18

A field in a LAN header that identifies the type of
header that follows the LAN header. Includes the
DIX Ethernet Type field, the IEEE 802.2 DSAP field,
and the SNAP protocol Type field.

Question 19

Shared Ethernet

Answer 19

An Ethernet that uses a hub, or even the original
coaxial cabling, which results in the devices having
to take turns sending data, sharing the available
bandwidth.

Question 20

Switch

Answer 20

A network device that filters, forwards,
and floods Ethernet frames based on
the destination address of each frame.

Question 21

Switched Ethernet

Answer 21

An Ethernet that uses a switch, and particularly not a hub, so that the devices
connected to one switch port do not have to contend to use the bandwidth
available on another port. This term contrasts with shared Ethernet, in which
the devices must share bandwidth, whereas switched Ethernet provides much
more capacity, as the devices do not have to share the available bandwidth.

Question 22

Twisted pair

Answer 22

Transmission medium consisting of two insulated wires, with the wires twisted
around each other in a spiral. An electrical circuit flows over the wire pair, with
the current in opposite directions on each wire, which significantly reduces the
interference between the two wires.