Section 2

Question 1

What are local-area networks?

Answer 1

Local area networks are high-speed, low-error data networks that cover a small geographical area.

Question 2

What are LAN standards?

Answer 2

LAN standards define the physical media and connectors used to connect to the media at the physical layer and the way devices communicate at the data link layer.
LAN standards encompass Layers 1 and 2 of the OSI model. An example of a LAN standard is Ethernet, which is also known as 802.3

Question 3

What are the typical components found in LANs?

Answer 3

Typical components found in LANs are:

• Computers (PCs, servers, tablets)
• Interconnections (NICs, media)
• Network devices (switches, routers, access points)
• Protocols (IP, ARP, DHCP)

Question 4

What is the logical topology of Ethernet?

Answer 4

Bus, Ethernet uses a logical bus topology and either a physical bus or a star topology.

Question 5

What are two types of Layer 1 network devices?

Answer 5

Repeaters and Hubs.

Question 6

What are some network devices that operate at the data link layer (Layer 2)?

Answer 6

Bridges and switches.

Question 7

What is a LAN segment?

Answer 7

A network connection made by a single unbroken network cable.

Question 8

What devices can you use to extend a LAN segment?

Answer 8

Hubs, Repeaters, Bridges, and Switches.

Question 9

How do collisions occur on an Ethernet LAN?

Answer 9

Collisions occur on a shared LAN segment when two devices try to transmit at the same time.

Question 10

What are collision domains?

Answer 10

A collision domain is a set of LAN interfaces whose frames could collide with each other.

Question 11

What happens when you segment the network with hubs/repeaters?

Answer 11

Hubs and repeaters operate at the physical layer of the OSI model; segmenting a network with these devices appears as an extention to the physical cable.
Hubs and repeaters are transparent devices; they are unintelligent devices. All devices that connect to a hub/repeater share the same bandwidth.

Question 12

What is the advantage of segmenting a LAN with switches?

Answer 12

Switches operate at layer 2 of the OSI model and filter and forward by MAC address. Each port on a switch provides fully dedicated bandwidth and creates a single collision domain. Because switches operate at layer 2, they cannot filter broadcasts, and they create a single broadcast domain.

Question 13

What devices are used to break up collision domains?

Answer 13

Switches, bridges, and routers.

Question 14

In an attempt to extend your Ethernet LAN segment, you add a 24-port hub. How many collision domains will you have in the segment with the addition of the hub?

Answer 14

1

Question 15

In an attempt to extend your Ethernet LAN segment, you add a 24-port switch. How many collision and broadcast domains will you have in the segment with the addition of a switch?

Answer 15

24

Question 16

What are broadcast domains?

Answer 16

A broadcast domain defines a group of devices that receive each other’s broadcast messages. As with collisions, the more broadcasts that occur on the network, the slower the network will be. This is because every devices that receives a broadcast must process it to see whether the broadcast was inteded for that device.

Question 17

You install a six-port router on your network. How many collision domains and broadcast domains will be created on the network with the addition of the six-port router?

Answer 17

Six collision domains and six broadcast domains will be created.

Question 18

What is a broadcast storm?

Answer 18

Broadcast storms occur when many broadcasts are sent simultaniously across all network segments. They are usually caused by Layer 2 loops because of spanning-tree configurations, a bad network interface card, a faulty network device, or a virus.