1-15 EXAMINING NETWORK SWITCHES

Question 1

What is a network switch?

Answer 1

A network device connecting devices inside local area networks (LAN) using MAC addresses to forward data to its destination.

Question 2

What is frame forwarding in the context of switches?

Answer 2

How switches use MAC addresses to determine the destination of a frame.

Question 3

What is a collision domain?

Answer 3

A network segment where only one device can transmit at a time.

Question 4

How do switches affect collision domains?

Answer 4

Switches reduce collisions and improve network performance.

Question 5

What are unmanaged switches?

Answer 5

Plug and play switches without configuration.

Question 6

What features do managed switches offer?

Answer 6

Features for configuration, VLAN setup, monitoring, etc.

Question 7

What do Layer 2 (Data Link) switches operate on?

Answer 7

MAC addresses.

Question 8

What distinguishes Layer 3 (Network) switches from Layer 2 switches?

Answer 8

Incorporate routing functions and operate using both MAC and IP addresses.

Question 9

What are multilayer switches?

Answer 9

Switches that operate at multiple layers, often combining Layer 2 and Layer 3 functions.

Question 10

What is a PoE (Power over Ethernet) switch?

Answer 10

A switch that delivers power and data over a single Ethernet cable.

Question 11

List the benefits of using switches.

Answer 11

• Efficiency: Reduced collisions and dedicated bandwidth for each connection.
• Performance: High-speed connectivity, especially in full-duplex mode.
• Flexibility: Scalability to accommodate growing networks.
• Security: Features like VLANs can segment network traffic.

Question 12

What is the process of store-and-forward switching?

Answer 12

The switch receives the entire data frame into its buffer, checks it for errors before forwarding it.

Question 13

What is the primary method of error checking in store-and-forward switching?

Answer 13

Cyclic Redundancy Check (CRC).

Question 14

What is a disadvantage of store-and-forward switching?

Answer 14

Higher latency, especially with larger frames.

Question 15

What is cut-through switching?

Answer 15

A method that begins forwarding the frame immediately after reading the destination MAC address.

Question 16

What is a key disadvantage of cut-through switching?

Answer 16

Potential for forwarding corrupted frames, as there is minimal error checking.

Question 17

What is fragment-free switching?

Answer 17

A variation of cut-through switching that waits for the first 64 bytes of the frame before forwarding.

Question 18

What is the latency characteristic of fragment-free switching?

Answer 18

Slightly higher latency than pure cut-through but less than store-and-forward.

Question 19

What advantage does fragment-free switching provide?

Answer 19

Balances low latency and error checking, reducing the chances of forwarding error frames.

Question 20

What is the purpose of the Preamble in an Ethernet Frame?

Answer 20

Alerts the receiving system of the incoming frame’s start and facilitates synchronization.

Question 21

What does SFD stand for and what is its function?

Answer 21

SFD stands for Start Frame Delimiter. It indicates that the Destination MAC Address field commences with the subsequent byte.

Question 22

What does the Destination MAC field specify?

Answer 22

Specifies the receiver of the frame.

Question 23

What does the Source MAC field specify?

Answer 23

Specifies the originator of the frame.

Question 24

What is the purpose of the Type field in an Ethernet Frame?

Answer 24

Designates the protocol type encapsulated within the frame, such as IPv4 or IPv6.

Question 25

What does the Data and Pad field hold?

Answer 25

Holds the frame’s payload. Padding is used to fulfill the minimum length requirement of this field, which is 46 bytes.

Question 26

What is included in the FCS (Frame Check Sequence)?

Answer 26

Includes a 32-bit Cyclic Redundancy Check (CRC), used for identifying any data corruption.