Network devices and the layers they operate at
Name:
Date:
Class:
A
Quick Questions
Shade in the A or B circle for each question.
1. A switch normally works at which layer of the OSI model?
2. Which statement about a hub is correct?
3. Which device is mainly responsible for forwarding packets between networks using IP addresses?
4. A layer 3 switch differs from a layer 2 switch because it can:
5. A network interface card (NIC) and a wireless access point operate at:
B
Match the Pairs
Draw a line connecting each item on the left to its match on the right.
| Left column | Right column | |
|---|---|---|
| 1Hub: Layer 1 (Physical) | AA hub does not read MAC addresses. It simply repeats signals at layer 1 (physical), so it is not a layer 2 device. | |
| 2Router: Layer 3 (Network) | BA hub only repeats electrical signals out of every port. It does not read addresses, so it works at the physical layer. | |
| 3A basic switch forwards frames using MAC addresses, so it works at the data link layer. | CLayer 3 switch: forwards by IP address | |
| 4A layer 3 switch can also route using IP addresses, so it works above the data link layer as well. | DSwitch (layer 2): MAC address table | |
| 5Hub: Layer 2 (reads MAC addresses) | EA router reads IP addresses in packets and chooses the next hop, so it works at the network layer. | |
| 6Firewall and proxy: Layer 1 only | FFirewalls and proxies inspect addresses, ports and application data. They work at layers 3 to 7, not just the physical layer. |
C
Definitions
device layer
D
Fill in the Blanks
Complete each line of code by filling in the missing parts.
1.
Hub: Layer _ (Physical)
2.
Layer 2 switch reads ___ addresses
3.
Layer 3 switch and router use __ addresses
4.
Proxy and firewall: Layers 3 to _
5.
Router works at the _______ layer (3)
E
Spot the Error
Shade in the letter of the line that contains an error.
Question 1
A
layers = {
B
'hub': 2,
C
'switch': 2,
D
'router': 3
E
}
Question 2
A
device = 'access point'
B
layers = [2, 3]
C
print(device, layers)
Question 3
A
sw_a = 'layer 2 switch'
B
uses = 'IP address'
C
layer = 2
Question 4
A
firewall = {
B
'name': 'packet filter',
C
'first': 3,
D
'last': 4
E
}
Question 5
A
proxy = {
B
'type': 'application',
C
'layer': 2
D
}
Answer Key
Network devices and the layers they operate at
Section A: Quick Questions
Q1
A — Layer 2 (Data Link)
Q2
A — A hub works at the Physical layer and just repeats the signal out of every port
Q3
B — Router (Network layer)
Q4
B — Route traffic using IP addresses as well as switch using MAC addresses
Q5
A — The Physical and Data Link layers (layers 1-2)
Section B: Match the Pairs
Q1
Hub: Layer 1 (Physical) → A hub only repeats electrical signals out of every port. It does not read addresses, so it works at the physical layer.
Q2
Router: Layer 3 (Network) → A router reads IP addresses in packets and chooses the next hop, so it works at the network layer.
Q3
A basic switch forwards frames using MAC addresses, so it works at the data link layer. → Switch (layer 2): MAC address table
Q4
A layer 3 switch can also route using IP addresses, so it works above the data link layer as well. → Layer 3 switch: forwards by IP address
Q5
Hub: Layer 2 (reads MAC addresses) → A hub does not read MAC addresses. It simply repeats signals at layer 1 (physical), so it is not a layer 2 device.
Q6
Firewall and proxy: Layer 1 only → Firewalls and proxies inspect addresses, ports and application data. They work at layers 3 to 7, not just the physical layer.
Section C: Definitions
Q1
device layer — The OSI layer a device works at: hubs at layer 1, NICs and access points at layers 1-2, switches at 2, routers at 3, and firewalls and proxies at layers 3 to 7.Section D: Fill in the Blanks
Q1
Hub: Layer 1 (Physical)Q2
Layer 2 switch reads MAC addressesQ3
Layer 3 switch and router use IP addressesQ4
Proxy and firewall: Layers 3 to 7Q5
Router works at the Network layer (3)Section E: Spot the Error
Q1
B — A hub only repeats electrical signals, so it works at layer 1 (physical), not layer 2. It should be 'hub': 1.
Q2
B — A wireless access point works at the physical and data link layers, which are layers 1 and 2. It should be [1, 2].
Q3
B — A layer 2 switch forwards frames using MAC addresses. It does not read IP addresses, which is what a layer 3 device does. It should be 'MAC address'.
Q4
D — Firewalls can inspect traffic from the network layer (3) up to the application layer (7). The last layer should be 7, not 4.
Q5
C — An application proxy works at the application layer, layer 7. It does not work at the data link layer (2). It should be 'layer': 7.