Networking: Switch Operations and Methods

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Questions and Answers

What is the main function of a MAC address table in a switch?

To maintain records of port connections to devices (correct)

To prioritize network bandwidth for different devices

To store the IP addresses of connected devices

To filter traffic based on port speed

Which factor is NOT typically considered when selecting a switch?

Cost

Speed

Brand reputation (correct)

Reliability

What does the process of address learning in switches involve?

Managing bandwidth allocation for necessary devices

Recording the destination MAC address of each received frame

Assigning IP addresses to connected devices

Learning source MAC addresses from incoming frames (correct)

What type of switch operates at Layer 3 of the OSI model?

Layer 3 switch Signup and view all the answers

Which configuration type allows for the combination of multiple switches into a single unit?

Stackable Configuration Signup and view all the answers

What is a primary goal of loop avoidance in switched networks?

To prevent multiple copies of the same frame Signup and view all the answers

Regarding port speed, which of the following is the fastest?

GigabitEthernet Signup and view all the answers

Which is a key characteristic of a modular configuration switch?

It allows expansion through additional modules Signup and view all the answers

What does a switch do when it receives a frame?

It checks the destination MAC address and uses the exit interface from the MAC address table. Signup and view all the answers

What is the primary purpose of the Spanning Tree Protocol (STP)?

To prevent network loops while allowing redundancy. Signup and view all the answers

What is a key feature of Store-and-Forward switching?

The entire frame is received and checked for errors before forwarding. Signup and view all the answers

How does Cut-Through switching function?

The switch makes a forwarding decision as soon as it sees the destination MAC address. Signup and view all the answers

What is the benefit of using Fragment Free switching?

It waits for the collision window to pass, improving error checking without significant latency. Signup and view all the answers

Which of the following is NOT a method of frame forwarding discussed?

Packet Relay Switching Signup and view all the answers

What happens to frames with errors in Cut-Through switching?

They are forwarded without any error checking. Signup and view all the answers

Which condition does a switch check using the Frame Check Sequence (FCS)?

The integrity of the frame after full reception. Signup and view all the answers

Study Notes

Forward/Filter Decisions

Switch identifies the exit interface using the destination MAC address found in the MAC address table.
Frames are forwarded only through the specified destination port.

Loop Avoidance

Redundant connections between switches may lead to network loops.
Spanning Tree Protocol (STP) effectively prevents loops while allowing redundancy in the network.

Switch Internal Processing

Switches process frames to ensure efficient data forwarding through various methods.

Frame Forwarding Methods

Store-and-Forward Switching
- Entire frame is received before forwarding.
- Switch verifies frame integrity by comparing frame-check-sequence (FCS) values.
- Only error-free frames are forwarded, enhancing reliability.
Cut-Through Switching
- Switch forwards frames immediately after determining the destination MAC address.
- Potentially forwards frames with errors, prioritizing speed over error-checking.
Fragment Free Switching
- A variation of cut-through switching that waits for the collision window (64 bytes) to pass.
- Better error checking than cut-through with minimal increase in latency.

Switch Types

Layer 2 Switch: Operates at Data Link layer, managing local traffic.
Layer 3 Switch: Operates at Network layer, can route packets.

Switch Form Factors

Fixed Configuration: Pre-defined ports and features.
Modular Configuration: Expandable with additional hardware modules.
Stackable Configuration: Several units can be stacked and managed as a single device.

Business Considerations for Switch Selection

Cost: Assess initial investment and long-term value.
Speed and Interfaces: Evaluate required bandwidth and port quantity.
Expansion Capability: Consider future network growth.
Port Density: Justify the number of devices on the network.
Power: Look into options for Power over Ethernet (PoE) and backup power supplies.
Reliability: Ensure switches provide continuous access.
Port Speed: Choose between Ethernet, FastEthernet, GigabitEthernet based on requirements.
Scalability: Anticipate network expansion needs.

Switch Functions

Address Learning: Switches store source MAC addresses from incoming frames into the MAC address table.
Forward/Filter Decisions: Based on the MAC address table, switches manage frame delivery.
Loop Avoidance: Mechanisms like STP are employed to manage potential network loops.

MAC Address Table

Switches construct a MAC address table that tracks the devices connected to each port.
This table is pivotal for determining how frames are processed and directed within the network.

Address Learning Process

Layer 2 switches and bridges accumulate source MAC addresses from received frames.
These addresses are entered into a MAC address table, forming the basis for future forwarding decisions.

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Description

This quiz focuses on the operations of network switches, including frame forwarding methods like Store-and-Forward and Cut-Through Switching. Additionally, it covers loop avoidance strategies such as the Spanning Tree Protocol (STP) and the process behind how switches handle data. Test your knowledge on the internal workings and decision-making processes of switches.