Learn Networking from very beginner to advanced through a complete course.
A network switch connects devices inside a LAN and forwards Ethernet frames to the correct destination. Switches are one of the most important devices in Networking.
In this chapter, you will learn Layer 2 vs Layer 3 switches, managed vs unmanaged switches, MAC address tables, frame forwarding, flooding, broadcasts, STP/RSTP, link aggregation, LACP, port mirroring, jumbo frames, PoE, and switch troubleshooting .
A switch is a network device that connects devices inside a local network.
PC1 ----\
PC2 ----- Switch ---- Router
PC3 ----/The switch allows PC1, PC2, and PC3 to communicate.
A switch primarily uses:
MAC addresses
to decide where Ethernet frames should go.
Think:
Switch = intelligent traffic director inside a LAN
A Layer 2 switch operates mainly at:
OSI Layer 2 — Data Link
It forwards:
Frames
using:
MAC addresses
PC A
MAC AA:AA:AA:AA:AA:AA
|
|
Switch
|
|
PC B
MAC BB:BB:BB:BB:BB:BBThe switch learns which MAC address is connected to which port.
A Layer 3 switch can perform normal switching and also routing functions.
That means it can work with:
VLAN 10
|
|
Layer 3 Switch
|
|
VLAN 20A Layer 3 switch can route traffic between the VLANs.
Layer 2 switch
= MAC + Frames
Layer 3 switch
= MAC + Frames + IP routingA managed switch can be configured by an administrator.
You can usually configure things such as:
Managed switches are common in businesses and enterprise networks.
An unmanaged switch is simpler.
You usually:
There is little or no configuration.
Internet
|
Router
|
Small unmanaged switch
/ | \
PC TV Printer| Managed | Unmanaged |
|---|---|
| Configurable | Plug-and-play |
| Enterprise features | Very limited configuration |
| Monitoring | Limited or no advanced monitoring |
| VLANs | Usually little or no VLAN configuration |
A switch keeps a list of MAC addresses and their associated ports.
This is called a:
MAC address table
It may also be called a:
CAM table
| MAC Address | Switch Port |
|---|---|
| AA:AA:AA:AA:AA:AA | Port 1 |
| BB:BB:BB:BB:BB:BB | Port 2 |
| CC:CC:CC:CC:CC:CC | Port 3 |
SWITCH
Connects devices inside a LAN
Forwards Ethernet frames
--------------------------------
LAYER 2 SWITCH
OSI Layer 2
Uses:
MAC addresses
Frames
--------------------------------
LAYER 3 SWITCH
Switching
+
Routing
Uses:
MAC addresses
IP addresses
VLANs
Routing
--------------------------------
LAYER 2 VS LAYER 3
Layer 2 switch
= MAC + Frames
Layer 3 switch
= MAC + Frames + IP routing
--------------------------------
MANAGED SWITCH
Configurable
Can support:
VLANs
Trunks
STP
Port security
Link aggregation
PoE settings
Monitoring
SNMP
Port mirroring
Speed and duplex
--------------------------------
UNMANAGED SWITCH
Plug-and-play
Little or no configuration
--------------------------------
MAC ADDRESS TABLE
Also called:
CAM table
Example:
AA:AA:AA:AA:AA:AA
→ Port 1
BB:BB:BB:BB:BB:BB
→ Port 2
CC:CC:CC:CC:CC:CC
→ Port 3Chapter 8 source complete.
What is the main purpose of a network switch?
A. Connect devices inside a LAN
B. Replace DNS
C. Assign public IP addresses
D. Provide Internet service by itself
A switch connects devices inside a local network and forwards Ethernet frames toward the correct destination.
What type of address does a Layer 2 switch primarily use?
A. IP address
B. MAC address
C. DNS name
D. TCP sequence number
A Layer 2 switch uses MAC addresses to decide where Ethernet frames go.
Which OSI layer is most closely associated with a Layer 2 switch?
A. Layer 1
B. Layer 2
C. Layer 3
D. Layer 7
A Layer 2 switch operates mainly at the Data Link layer.
What does a Layer 2 switch forward?
A. Frames
B. Files only
C. DNS records
D. Applications
Layer 2 switches forward Ethernet frames using MAC-address information.
What extra capability does a Layer 3 switch have?
A. Routing
B. It removes MAC addresses
C. It only works with Wi-Fi
D. It cannot use VLANs
A Layer 3 switch can perform normal switching and also route traffic.
Which information can a Layer 3 switch work with?
A. MAC addresses only
B. MAC addresses and IP addresses
C. DNS names only
D. TCP ports only
A Layer 3 switch can use both Layer 2 MAC information and Layer 3 IP information.
Which switch type can route traffic between VLAN 10 and VLAN 20?
A. Layer 3 switch
B. Basic hub
C. Patch panel
D. Repeater only
A Layer 3 switch can perform inter-VLAN routing.
Which statement correctly compares Layer 2 and Layer 3 switches?
A. Layer 2 = MAC + Frames; Layer 3 = MAC + Frames + IP routing
B. Layer 2 = IP only; Layer 3 = MAC only
C. Both are Layer 1 devices only
D. Layer 3 switches cannot use VLANs
This is the key distinction from your Chapter 8 material.
What is a managed switch?
A. A configurable switch
B. A switch that cannot be configured
C. A switch with no ports
D. A router only
Managed switches allow administrators to configure advanced network features.
Which feature is commonly available on a managed switch?
A. VLAN configuration
B. No configuration at all
C. No monitoring
D. No port settings
Managed switches can commonly configure VLANs, trunks, STP, port security, and other features.
Which switch type is most common in enterprise networks?
A. Managed switch
B. Unmanaged hub only
C. Repeater only
D. Patch panel
Managed switches are common in businesses and enterprise environments.
What best describes an unmanaged switch?
A. Plug-and-play
B. Requires complex routing configuration
C. Always provides advanced VLAN control
D. Works only as a router
An unmanaged switch normally works automatically with little or no configuration.
Which environment is a good example for an unmanaged switch?
A. Small simple network
B. Complex enterprise requiring advanced VLAN policies
C. Large data center core only
D. Internet service provider backbone only
Unmanaged switches are useful when basic connectivity is needed without advanced configuration.
What does a switch store in a MAC address table?
A. MAC addresses and associated switch ports
B. DNS names only
C. User passwords
D. Internet URLs
A switch uses this table to know which port leads to a particular MAC address.
What is another name for a MAC address table?
A. CAM table
B. DNS table
C. ARP-only table
D. Routing protocol table
The MAC address table may also be called a CAM table.
A switch learns MAC address AA:AA:AA:AA:AA:AA on Port 1. What does that mean?
A. That MAC address is reachable through Port 1
B. Port 1 is automatically a router
C. The MAC address becomes an IP address
D. The switch must delete Port 1
The switch associates learned MAC addresses with the ports on which they are observed.
Which managed-switch feature helps prevent switching loops?
A. STP
B. HTTP
C. DNS
D. DHCP
STP is one of the switch features named in the Chapter 8 material and is used to manage redundant Layer 2 paths.
What does RSTP provide compared with traditional STP?
A. Faster spanning-tree convergence
B. DNS resolution
C. Email transport
D. IP address assignment
RSTP is the rapid version of spanning tree and is intended to converge faster than traditional STP.
What is link aggregation used for?
A. Combine multiple physical links into one logical link
B. Replace MAC addresses
C. Assign DNS names
D. Disable switch redundancy
Link aggregation can increase bandwidth and provide redundancy.
Which protocol is associated with link aggregation negotiation?
A. LACP
B. SMTP
C. NTP
D. POP3
LACP is the link-aggregation protocol named in your Chapter 8 introduction.
What is port mirroring used for?
A. Copy traffic for monitoring or analysis
B. Increase monitor screen brightness
C. Assign IP addresses
D. Encrypt all VLAN traffic automatically
Port mirroring allows selected network traffic to be copied to another port for troubleshooting or monitoring.
What are jumbo frames?
A. Ethernet frames larger than the standard frame size
B. Tiny DNS packets only
C. Wireless-only packets
D. Router configuration files
Jumbo frames are larger Ethernet frames and may be used in environments where supported end-to-end.
What does PoE allow a switch to provide?
A. Electrical power over Ethernet cabling
B. DNS resolution
C. Public IP addresses
D. Fiber light directly to a PC
PoE can provide both data connectivity and electrical power through Ethernet cabling.
Which device commonly benefits from PoE?
A. Wireless access point
B. Passive patch panel only
C. Standard paper document
D. DNS record
PoE is commonly useful for devices such as access points, IP phones, and cameras.
Which feature allows an administrator to monitor a managed switch?
A. SNMP
B. POP3
C. FTP only
D. TFTP only
SNMP is listed among the configurable and monitoring features of a managed switch.
Which switch feature can restrict which devices are allowed on a port?
A. Port security
B. DNS
C. NTP
D. SMTP
Port security is a managed-switch feature used to control device access at a switch port.
Which switch setting can help fix a link that is up but performing poorly?
A. Speed and duplex
B. DNS domain name only
C. SMTP port only
D. POP3 mailbox
Managed switches often allow speed and duplex configuration, which can be important when troubleshooting link problems.
A network requires VLANs, trunks, STP, monitoring, and port security. Which switch type should be chosen?
A. Managed switch
B. Unmanaged switch
C. Hub
D. Repeater
These are advanced features associated with managed switches.
A small home setup only needs extra Ethernet ports and no advanced configuration. Which device is most appropriate?
A. Unmanaged switch
B. Layer 3 core switch only
C. Enterprise firewall only
D. Router-on-a-stick
An unmanaged switch is suitable for simple plug-and-play connectivity.
Which statement correctly summarizes a network switch?
A. A switch connects LAN devices and primarily forwards Ethernet frames using MAC-address information.
B. A switch only resolves DNS names.
C. A switch has no knowledge of MAC addresses.
D. All switches are unmanaged and cannot be configured.
Layer 2 switches primarily use MAC addresses and frames. Layer 3 switches add IP-routing capabilities.
Exam memory: Layer 2 switch = MAC + Frames. Layer 3 switch = MAC + Frames + IP routing. Managed = configurable. Unmanaged = plug-and-play. MAC address table = CAM table.
A modern course built to help learners study step by step with clarity, comfort, and confidence.