N10-008 Exam Questions: Which Statement Describes the Behavior of a Switch When the MAC Address Table Is Full?

The CompTIA Network+ (N10-008) certification is a globally recognized credential for IT professionals, validating foundational networking skills in design, configuration, management, and troubleshooting. A key exam question, “Which statement describes the behavior of a switch when the MAC address table is full?” highlights that the switch floods frames to all ports (except the receiving port), acting like a hub, tested within Domain 1: Networking Fundamentals (24%) and Domain 2: Network Implementations (25%). These domains cover switching concepts, device configurations, and network operations, essential for roles like network technicians, help desk analysts, and junior network administrators.

The N10-008 exam, lasting 90 minutes with 90 questions, includes multiple-choice, drag-and-drop, and performance-based questions, requiring a passing score of 720 (on a 100–900 scale). Study4Pass is a premier resource for N10-008 - CompTIA Network+ Certification Exam Prep, offering comprehensive study guides, practice exams, and hands-on labs tailored to the exam syllabus. This article explores MAC address tables, their behavior when full, real-world implications, and strategic preparation tips using Study4Pass to excel in the CompTIA N10-008 certification exam.

Introduction to MAC Address Tables

What is a MAC Address Table?

The MAC address table, also known as the Content Addressable Memory (CAM) table, is a dynamic database maintained by a Layer 2 switch to map MAC addresses to switch ports. This table enables the switch to forward frames efficiently to the correct destination, reducing unnecessary traffic compared to a hub.

Key Functions:

• Learning: The switch records the source MAC address and port of incoming frames.
• Forwarding: Uses the table to send frames to specific ports based on destination MAC addresses.
• Aging: Removes inactive entries after a timeout (default: 300 seconds).

Example: A switch receives a frame from MAC 00:1A:2B:3C:4D:5E on port Fa0/1. It adds this MAC-to-port mapping to the table and uses it to forward future frames.

Importance in Networking

The MAC address table is critical for:

• Efficiency: Prevents flooding by directing frames to specific ports.
• Scalability: Supports large networks with thousands of devices.
• Security: Enables features like port security to restrict unauthorized MACs.

For N10-008 candidates, understanding the MAC address table is foundational, as it underpins Layer 2 switching and troubleshooting. Study4Pass provides detailed guides on switching concepts, supported by practice questions that reinforce table operations.

Relevance to CompTIA N10-008 Exam

The N10-008 exam tests MAC address table behavior in objectives like “Explain the purpose and characteristics of network devices” and “Troubleshoot common network issues.” Candidates must:

• Describe normal table operations (learning, forwarding, aging).
• Understand behavior when the table is full (flooding like a hub).
• Troubleshoot related issues (e.g., performance degradation).

Exam questions may involve selecting correct behaviors, analyzing scenarios, or configuring switches. Study4Pass aligns its resources with these objectives, offering labs and practice exams that mirror real-world switching scenarios.

MAC Address Table Capacity Fundamentals

Table Size and Limitations

• Capacity: Varies by switch model, ranging from 1,000 to 128,000 entries (e.g., Cisco Catalyst 2950: ~8,000; Catalyst 9300: ~32,000).
• Storage: Resides in switch RAM or CAM, a high-speed memory for fast lookups.
• Factors Affecting Size:
  o    Switch Model: Enterprise switches have larger tables than SOHO models.
  o    Network Size: Large networks with many devices require more entries.
  o    VLANs: Each VLAN maintains a separate table, multiplying capacity needs.

Example: A small office switch with 2,000 entries suffices for 50 devices, but a data center switch needs 64,000 for thousands of VMs.

Dynamic vs. Static Entries

• Dynamic Entries:
  o    Learned automatically from incoming frames.
  o    Subject to aging (e.g., removed after 300 seconds of inactivity).
  o    Example: A PC’s MAC is added when it sends traffic.
• Static Entries:
  o    Manually configured for specific devices (e.g., servers).
  o    Do not age out, reducing available dynamic entries.
  o    Command: mac address-table static 00:1A:2B:3C:4D:5E vlan 10 interface Fa0/1.

Table Full Scenario

When the MAC address table reaches capacity:

• Behavior: The switch cannot add new MAC addresses and floods frames with unknown destination MACs to all ports (except the receiving port), mimicking a hub.
• Impact: Increases network traffic, degrades performance, and poses security risks (e.g., easier packet sniffing).
• Example: A switch with a full 8,000-entry table floods frames for a new device, causing congestion.

For N10-008 candidates, mastering table capacity is critical. Study4Pass flashcards summarize table mechanics, ensuring quick recall.

Critical Exam Scenario: Table Full Condition

Behavior When the MAC Address Table is Full

When the table is full:

• Flooding: Frames with unknown or new destination MACs are sent to all ports (except the source port), as the switch cannot learn new mappings.
• Hub-Like Operation: The switch behaves like a hub, broadcasting traffic indiscriminately.
• Performance Impact: Flooding increases bandwidth usage, leading to congestion and latency.
• Security Risk: Broadcasted frames are visible to all devices, increasing eavesdropping risks.

Example: In a network with a full table, a new PC’s traffic is flooded, slowing down VoIP calls and exposing data to unauthorized devices.

Why This Happens

• Capacity Limit: The table’s fixed size (e.g., 8,000 entries) is exhausted.
• High Device Count: Dense environments (e.g., data centers) exceed table limits.
• Misconfiguration: Excessive static entries or disabled aging reduce dynamic space.
• Attack: MAC flooding attacks (e.g., sending fake MACs) deliberately fill the table.

Exam Relevance

• Question Type: “Which statement describes the behavior of a switch when the MAC address table is full?”
  o    Correct Answer: The switch floods frames to all ports except the receiving port.
  o    Incorrect Options: Continues normal operation, drops frames, or reboots.
• Study4Pass Tip: Practice scenario-based questions to identify flooding behavior.

Study4Pass guides detail this scenario, supported by labs simulating full tables.

Real-World Implications

Network Performance Degradation

• Issue: Flooding consumes bandwidth, causing delays for critical applications (e.g., ERP, VoIP).
• Example: A full table in a campus network slows video conferencing due to excessive broadcasts.
• Impact: Reduced user productivity and poor QoS.

Security Vulnerabilities

• Issue: Flooded frames are accessible to all devices, enabling packet sniffing.
• Example: An attacker captures sensitive data (e.g., credentials) during flooding.
• Impact: Data breaches, compliance violations (e.g., GDPR, HIPAA).

Scalability Challenges

• Issue: Small table sizes limit network growth in dense environments.
• Example: A switch with 4,000 entries struggles in a 5,000-device network.
• Impact: Requires costly hardware upgrades.

Case Study: Enterprise Network Congestion

• Scenario: A company’s Cisco 2950 switch (8,000 entries) supports 7,500 devices. A new department adds 1,000 IoT devices, filling the table.
• Issue: Flooding causes network slowdowns and VoIP jitter.
• Solution:
  I.      Upgrade to a Catalyst 9300 (32,000 entries).
  II.      Enable port security to limit MACs per port.
  III.      Monitor table usage with show mac address-table count.
• Outcome: Restored performance, enhanced security.

Study4Pass PDF Exam Questions simulate these implications, reinforcing real-world applications.

Troubleshooting & Mitigation

Identifying a Full Table

• Command: show mac address-table count (displays total and used entries).
• Example Output:
• Total MAC Addresses: 8000
Used MAC Addresses: 7998
• Symptoms: Increased broadcast traffic, slow network, Wireshark showing flooded frames.
• Tool: SNMP monitoring (e.g., SolarWinds) for table usage alerts.

Mitigation Strategies

1. Increase Table Size:
   o    Upgrade to a switch with a larger CAM table (e.g., Cisco Catalyst 9200).
   o    Example: Replace a 4,000-entry switch with a 16,000-entry model.
2. Adjust Aging Time:
   o    Reduce aging (e.g., 120 seconds): mac address-table aging-time 120.
   o    Example: Free up entries for inactive devices in a dynamic environment.
3. Implement Port Security:
   o    Limit MACs per port: switchport port-security maximum 2.
   o    Example: Restrict a port to two devices to prevent table overflow.
4. VLAN Segmentation:
   o    Divide devices into VLANs to reduce table load per VLAN.
   o    Example: Separate IoT and corporate devices into VLAN 10 and 20.
5. Detect Attacks:
   o    Enable port security to block MAC flooding: switchport port-security violation shutdown.
   o    Example: Shut down a port sending fake MACs.

Troubleshooting Steps

1. Verify Table Status: Run show mac address-table count.
2. Check Traffic: Use Wireshark to confirm flooding.
3. Review Configurations: Ensure aging and port security are optimized.
4. Test Mitigation: Apply VLANs or port security, then recheck performance.

• Example: A technician notices slow network performance, confirms a full table (8,000/8,000 entries), reduces aging to 100 seconds, and restores normal operation.

Study4Pass labs provide virtual switches to practice these techniques, ensuring troubleshooting proficiency.

CompTIA N10-008 Exam Focus

MAC Address Table Topics

• Objectives:
  o    Explain switch operations (learning, forwarding, flooding).
  o    Troubleshoot Layer 2 issues (e.g., full tables, misconfigurations).
  o    Configure switch security features (e.g., port security).
• Topics:
  o    Table capacity and behavior.
  o    Commands like show mac address-table.
  o    Mitigation for full tables.

Common Question Types

• Multiple-Choice: “What happens when the MAC address table is full?” (Answer: Floods frames).
• Performance-Based: Configure port security to prevent table overflow.
• Scenario-Based: Diagnose slow network due to a full table.
• Example: “A switch floods traffic after adding new devices. What is the cause?” (Answer: Full MAC address table).

Importance of Mastery

• Exam Success: Directly tested in switching and troubleshooting questions.
• Real-World Skills: Essential for maintaining efficient, secure networks.
• Study4Pass Tip: Practice 50 table-focused questions.

Study4Pass practice exams include these question types, ensuring exam readiness.

Study Resources for CompTIA N10-008 Exam Prep

Study4Pass Resources

• Guides: 150+ pages on switching, MAC tables, and troubleshooting.
• Practice Tests: 200+ questions, including performance-based tasks.
• Labs: Virtual switches (e.g., Cisco Packet Tracer) for table management.
• Forums: Peer support for Layer 2 issues.
• Tip: Use Study4Pass’s switching cheat sheet for quick reference.

Recommended Labs

1. Lab 1: Table Monitoring:
   o    Run show mac address-table count on a switch.
   o    Simulate new devices to approach capacity.
   o    Outcome: Understood table limits.
2. Lab 2: Port Security:
   o    Configure switchport port-security maximum 2 on a port.
   o    Test with multiple devices to trigger violations.
   o    Outcome: Mastered security mitigation.
3. Lab 3: Troubleshooting:
   o    Simulate a full table, observe flooding with Wireshark.
   o    Apply VLAN segmentation to resolve.
   o    Outcome: Learned troubleshooting steps.

Study Plan

• Weeks 1–2: Memorize table operations, flooding behavior, commands.
• Weeks 3–4: Practice labs (table monitoring, port security, VLANs).
• Weeks 5–6: Solve 100-question practice tests, focus on scenarios.
• Study4Pass Tip: Review incorrect answers to strengthen weak areas.

Bottom Line

The CompTIA Network+ N10-008 certification equips IT professionals with essential networking skills, with MAC address table behavior—especially flooding when full—as a critical topic in Networking Fundamentals and Network Implementations. Understanding table capacity, troubleshooting flooding, and mitigating issues like congestion and security risks ensures exam success and proficiency in managing Layer 2 switches.

Study4Pass is the ultimate resource for N10-008 preparation, offering study guides, practice exams, and hands-on labs that replicate real-world switching scenarios. Its table-focused labs and scenario-based questions ensure candidates can monitor tables, configure security, and troubleshoot issues confidently. With Study4Pass, aspiring Network+ professionals can ace the exam and launch rewarding careers, with salaries averaging $60,000–$85,000 annually (Glassdoor, 2025).

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Practice Questions from CompTIA N10-008 Certification Exam

Which statement describes the behavior of a switch when the MAC address table is full?

A. The switch drops all incoming frames.
B. The switch floods frames to all ports except the receiving port.
C. The switch reboots to clear the table.
D. The switch continues normal operation without flooding.

Which command displays the current MAC address table entries on a switch?

A. show running-config
B. show mac address-table
C. show interfaces
D. show vlan brief

A network technician notices increased broadcast traffic. What is a likely cause?

A. A full MAC address table
B. A misconfigured VLAN
C. A faulty cable
D. An incorrect IP address

Which mitigation prevents a MAC address table from becoming full due to unauthorized devices?

A. Enable QoS
B. Configure port security
C. Increase switch bandwidth
D. Disable VLANs

What is the default aging time for dynamic MAC address table entries?

A. 60 seconds
B. 120 seconds
C. 300 seconds
D. 600 seconds