2.2 Flashcards by Brandon Palmer

What is the purpose of a VLAN database on a switch?

Stores VLAN IDs and names for configuration and reference
Controls physical port speed
Stores DNS records for the switch
Manages SSH credentials

✅ Correct Answer: Stores VLAN IDs and names for configuration and reference

📘 Explanation: The VLAN database keeps track of configured VLANs and their associated details, allowing for consistent application.

📌 Practical Use Case: A network admin uses the VLAN database to check which VLAN IDs are already in use before creating a new one.

📚 Exam Objective Reference: 2.2 – VLAN database

🔁 Follow-Up: How can you view or modify the VLAN database on a Cisco switch?

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What is a Switch Virtual Interface (SVI) used for?

Tags traffic with 802.1Q headers
Extends a VLAN across routers
Assigns MAC addresses to ports
Provides Layer 3 IP connectivity to a VLAN

✅ Correct Answer: Provides Layer 3 IP connectivity to a VLAN

📘 Explanation: SVIs allow switches to route between VLANs by assigning IP addresses to virtual interfaces.

📌 Practical Use Case: A network uses SVIs to route traffic between VLAN 10 and VLAN 20 internally without a separate router.

📚 Exam Objective Reference: 2.2 – Switch Virtual Interface (SVI)

🔁 Follow-Up: What command is used to assign an IP address to an SVI?

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What is the function of a native VLAN on a trunk port?

Prevents VLAN hopping
Carries untagged traffic across the trunk link
Encrypts VLAN data
Assigns a dynamic VLAN ID to voice devices

✅ Correct Answer: Carries untagged traffic across the trunk link

📘 Explanation: The native VLAN allows untagged traffic to pass on trunk ports, typically used for management or legacy devices.

📌 Practical Use Case: A printer that doesn’t support VLAN tagging is placed on the native VLAN so it can still communicate.

📚 Exam Objective Reference: 2.2 – Native VLAN

🔁 Follow-Up: What risk is associated with an unconfigured native VLAN?

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How is a voice VLAN different from a data VLAN?

It encrypts all data traffic
It assigns static IP addresses
It blocks internet access
It prioritizes traffic for IP phones using QoS

✅ Correct Answer: It prioritizes traffic for IP phones using QoS

📘 Explanation: Voice VLANs are configured to ensure voice traffic receives higher priority over data on the same link.

📌 Practical Use Case: IP phones and computers share a port; the phone uses the voice VLAN for guaranteed call quality.

📚 Exam Objective Reference: 2.2 – Voice VLAN

🔁 Follow-Up: What switch configuration enables a port to support both voice and data VLANs?

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What does 802.1Q tagging allow on a trunk link?

It disables MAC flooding
It encrypts VLAN traffic
It prevents duplex mismatches
It allows multiple VLANs to be identified over a single physical connection

✅ Correct Answer: It allows multiple VLANs to be identified over a single physical connection

📘 Explanation: 802.1Q tagging inserts VLAN ID headers into Ethernet frames for proper delivery across trunk links.

📌 Practical Use Case: A switch uses 802.1Q to send VLAN 10 and VLAN 20 traffic to another switch over the same port.

📚 Exam Objective Reference: 2.2 – 802.1Q tagging

🔁 Follow-Up: What field in the Ethernet frame is modified by 802.1Q?

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What is the benefit of link aggregation?

Allows VoIP without VLANs
Increases bandwidth and provides redundancy between switches
Prevents switch boot failures
Disables broadcast domains

✅ Correct Answer: Increases bandwidth and provides redundancy between switches

📘 Explanation: Link aggregation combines multiple physical links into a single logical link to improve performance and failover.

📌 Practical Use Case: Two switches are connected with four Ethernet cables in an aggregated group to improve throughput.

📚 Exam Objective Reference: 2.2 – Link aggregation

🔁 Follow-Up: What protocols are used for link aggregation negotiation?

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What does configuring a switch port for auto speed do?

Allows the port to negotiate speed with the connected device
Forces full duplex mode
Disables VLAN tagging
Locks the port at 100 Mbps

✅ Correct Answer: Allows the port to negotiate speed with the connected device

📘 Explanation: Auto speed enables devices to negotiate the highest mutually supported speed during connection setup.

📌 Practical Use Case: A technician plugs a laptop into a switch, and the port auto-negotiates to 1 Gbps based on the NIC.

📚 Exam Objective Reference: 2.2 – Speed

🔁 Follow-Up: What happens if auto speed fails to negotiate properly?

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What is a common symptom of a duplex mismatch between two switch ports?

Incorrect VLAN assignment
Slow network performance and high collisions
Broadcast storm from STP
MAC address duplication

✅ Correct Answer: Slow network performance and high collisions

📘 Explanation: Duplex mismatches result in one side using full duplex while the other uses half, causing frame loss and retransmissions.

📌 Practical Use Case: A user reports slow file transfers because their PC is set to full duplex, but the switch port is on half duplex.

📚 Exam Objective Reference: 2.2 – Duplex

🔁 Follow-Up: How can you check duplex settings on a Cisco switch?

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

Prevents switching loops by blocking redundant paths
Configures access control lists
Assigns IP addresses to switches
Encrypts VLAN traffic

✅ Correct Answer: Prevents switching loops by blocking redundant paths

📘 Explanation: STP detects and disables redundant switch paths to prevent broadcast storms and loops.

📌 Practical Use Case: A network uses STP to block one of two paths between switches to avoid looping broadcast traffic.

📚 Exam Objective Reference: 2.2 – Spanning Tree

🔁 Follow-Up: What is the default STP protocol version used by most modern switches?

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What is a jumbo frame?

A packet used only by STP
A frame that contains multiple VLAN tags
An Ethernet frame that exceeds the standard 1500-byte MTU
A broadcast frame with priority tagging

✅ Correct Answer: An Ethernet frame that exceeds the standard 1500-byte MTU

📘 Explanation: Jumbo frames allow larger payloads (often 9000 bytes) to reduce overhead in high-throughput environments.

📌 Practical Use Case: A storage network enables jumbo frames to optimize file transfers over a 10 Gbps link.

📚 Exam Objective Reference: 2.2 – MTU / Jumbo Frames

🔁 Follow-Up: Why must all devices in a path support jumbo frames for them to work correctly?

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What does BPDU Guard do in Spanning Tree Protocol?

Disables a port if a BPDU is received, protecting the STP topology
Sends BPDUs to all VLANs
Enables jumbo frame inspection
Automatically promotes the port to root

✅ Correct Answer: Disables a port if a BPDU is received, protecting the STP topology

📘 Explanation: BPDU Guard prevents edge ports from participating in STP if a BPDU is received, protecting against rogue switches.

📌 Practical Use Case: BPDU Guard shuts down a user port that mistakenly receives a BPDU from an unauthorized switch.

📚 Exam Objective Reference: 2.2 – Spanning Tree (BPDU Guard)

🔁 Follow-Up: When should BPDU Guard be enabled on access ports?

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What is the purpose of Loop Guard in Spanning Tree Protocol?

Prevents loops by blocking ports that stop receiving BPDUs
Forces root bridge reelection
Enables load balancing on VLANs
Allows voice VLANs on trunk ports

✅ Correct Answer: Prevents loops by blocking ports that stop receiving BPDUs

📘 Explanation: Loop Guard maintains STP stability by blocking non-designated ports if BPDUs stop arriving unexpectedly.

📌 Practical Use Case: A port stops receiving BPDUs due to a unidirectional link; Loop Guard keeps the port in a blocking state.

📚 Exam Objective Reference: 2.2 – Spanning Tree (Loop Guard)

🔁 Follow-Up: How does Loop Guard differ from Root Guard?

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What are the main STP port states during convergence?

Initialize, Commit, Accept
Hold, Start, Push, Pull
Blocking, Listening, Learning, Forwarding, Disabled
Idle, Waiting, Sending, Receiving

✅ Correct Answer: Blocking, Listening, Learning, Forwarding, Disabled

📘 Explanation: STP transitions ports through several states to safely establish a loop-free topology.

📌 Practical Use Case: A technician observes a port in the learning state while STP recalculates after a topology change.

📚 Exam Objective Reference: 2.2 – Spanning Tree

🔁 Follow-Up: Which port state learns MAC addresses but doesn’t forward frames?

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What happens when MTU values are mismatched between switches?

STP disables the interfaces
MAC address tables are erased
VLANs are merged automatically
Traffic may be dropped or fragmented, causing performance issues

✅ Correct Answer: Traffic may be dropped or fragmented, causing performance issues

📘 Explanation: MTU mismatches lead to dropped frames or fragmentation, especially with jumbo frames.

📌 Practical Use Case: A switch fails to transfer large backup files due to MTU mismatch with the upstream core switch.

📚 Exam Objective Reference: 2.2 – MTU

🔁 Follow-Up: What command can verify MTU on a Cisco interface?

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How can you verify if jumbo frames are supported on a switch port?

Check the MTU setting and supported frame size on the interface
Enable port security and check logs
Use STP root guard
Ping the VLAN interface

✅ Correct Answer: Check the MTU setting and supported frame size on the interface

📘 Explanation: You must confirm the interface supports higher-than-standard MTU and that jumbo frames are enabled.

📌 Practical Use Case: An admin enables jumbo frames to support a SAN that requires 9000-byte frames.

📚 Exam Objective Reference: 2.2 – Jumbo Frames

🔁 Follow-Up: How do you test jumbo frame support using ping?

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What does ‘allowed VLANs’ mean in trunk configuration?

Creates new VLANs automatically
Specifies which VLANs are permitted to traverse the trunk link
Blocks voice VLANs by default
Forces trunk ports to become access ports

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✅ Correct Answer: Specifies which VLANs are permitted to traverse the trunk link

📘 Explanation: Allowed VLANs limit trunk traffic to only those explicitly listed, enhancing control and security.

📌 Practical Use Case: An admin restricts a trunk to only carry VLANs 10, 20, and 30 to prevent broadcast storms.

📚 Exam Objective Reference: 2.2 – Trunking

🔁 Follow-Up: What command shows which VLANs are allowed on a trunk?

What occurs if a VLAN is not allowed on a trunk link?

The switch shuts down
Port changes to dynamic mode
Traffic for that VLAN is dropped at the trunk port
VLAN is automatically created

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✅ Correct Answer: Traffic for that VLAN is dropped at the trunk port

📘 Explanation: If a VLAN isn’t part of the trunk’s allowed list, frames tagged with that VLAN are discarded.

📌 Practical Use Case: VLAN 50 traffic doesn’t pass between switches because it’s not included in the trunk’s allowed VLAN list.

📚 Exam Objective Reference: 2.2 – Trunking

🔁 Follow-Up: How do you add a VLAN to the allowed list on a trunk port?

What is a sign of misconfigured voice and data VLANs on a switch port?

MAC address flooding
STP loop detection
Excessive broadcast traffic
Phones fail to get IP addresses or register with the call server

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✅ Correct Answer: Phones fail to get IP addresses or register with the call server

📘 Explanation: Incorrect VLAN assignment can prevent IP phones from communicating with DHCP or VoIP services.

📌 Practical Use Case: An office reports all phones offline because the switch ports have no voice VLAN configured.

📚 Exam Objective Reference: 2.2 – Voice VLAN

🔁 Follow-Up: What Cisco command assigns a voice VLAN to a port?

What issue arises when two trunk ports have different native VLANs?

Trunk negotiation is reversed
All ports enter blocking state
Untagged traffic is misinterpreted, leading to VLAN confusion
STP is disabled

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✅ Correct Answer: Untagged traffic is misinterpreted, leading to VLAN confusion

📘 Explanation: Mismatch in native VLANs causes untagged frames to be misrouted or discarded.

📌 Practical Use Case: A network sees management traffic dropped between switches due to mismatched native VLANs.

📚 Exam Objective Reference: 2.2 – Native VLAN

🔁 Follow-Up: What command checks native VLAN on both sides of a trunk?

What causes a link aggregation group to fail even if physical links are connected?

MAC address aging timers
Port security is disabled
Inconsistent port settings (speed, duplex, VLANs)
Trunking protocol mismatch

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✅ Correct Answer: Inconsistent port settings (speed, duplex, VLANs)

📘 Explanation: All physical interfaces in an aggregation group must have identical configurations.

📌 Practical Use Case: Only 2 of 4 aggregated ports come online due to a speed mismatch on one port.

📚 Exam Objective Reference: 2.2 – Link Aggregation

🔁 Follow-Up: Which show command helps verify port-channel consistency?

How can you test if STP is blocking a redundant link?

Enable port security
Change interface to access mode
Use show spanning-tree to check port state
Ping the root bridge directly

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✅ Correct Answer: Use show spanning-tree to check port state

📘 Explanation: The show spanning-tree command displays each port’s STP state, confirming if it’s forwarding or blocking.

📌 Practical Use Case: An admin sees one uplink in blocking state to prevent loops due to STP topology decisions.

📚 Exam Objective Reference: 2.2 – Spanning Tree

🔁 Follow-Up: What causes a port to enter blocking state in STP?

Why is the native VLAN a potential security risk?

It disables voice VLAN functionality
It triggers jumbo frame floods
It prevents STP from operating
Untagged traffic can be intercepted or misrouted if not secured

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✅ Correct Answer: Untagged traffic can be intercepted or misrouted if not secured

📘 Explanation: Since untagged traffic travels on the native VLAN, attackers can exploit misconfigurations or spoof VLANs.

📌 Practical Use Case: An attacker gains access to sensitive data by injecting untagged traffic into a trunk link using the native VLAN.

📚 Exam Objective Reference: 2.2 – Native VLAN

🔁 Follow-Up: How can you secure the native VLAN on trunk ports?

What happens if both ends of a trunk port are set to different native VLANs?

Trunking is disabled
Spanning Tree blocks the port
Voice VLAN is automatically reset
Traffic may be misrouted or dropped due to VLAN mismatch

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✅ Correct Answer: Traffic may be misrouted or dropped due to VLAN mismatch

📘 Explanation: A native VLAN mismatch can cause confusion about which VLAN untagged traffic belongs to, disrupting communication.

📌 Practical Use Case: Two switches on a trunk link fail to pass management traffic due to native VLAN mismatch.

📚 Exam Objective Reference: 2.2 – Native VLAN

🔁 Follow-Up: What command shows native VLAN configuration on a trunk?

How does a switch treat voice traffic in a configured voice VLAN?

It tags voice traffic for prioritization over data
It blocks it from crossing trunk links
It compresses it before transmission
It tunnels it over HTTP

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✅ Correct Answer: It tags voice traffic for prioritization over data

📘 Explanation: Voice VLANs tag voice traffic for QoS, ensuring lower latency and jitter.

📌 Practical Use Case: An IP phone on a switch port sends voice traffic over the voice VLAN and data traffic from a PC on the same port over the data VLAN.

📚 Exam Objective Reference: 2.2 – Voice VLAN

🔁 Follow-Up: Which command assigns a voice VLAN to a switch port?

What does link aggregation require to function correctly? - Matching speed and duplex on all aggregated interfaces - Dynamic VLAN assignment - Multiple routing protocols enabled - Jumbo frames disabled

✅ Correct Answer: Matching speed and duplex on all aggregated interfaces 📘 Explanation: All links in an aggregation group must match in speed and duplex to operate without errors. 📌 Practical Use Case: A switch blocks one of four aggregated links because it’s set to half-duplex while others are full-duplex. 📚 Exam Objective Reference: 2.2 – Link aggregation 🔁 Follow-Up: Which protocol dynamically negotiates link aggregation?

What condition can cause a duplex mismatch? - Both devices use the same MAC address - One device is set to auto and the other is hardcoded to full - IP conflict on different VLANs - STP is disabled on both sides

✅ Correct Answer: One device is set to auto and the other is hardcoded to full 📘 Explanation: Auto-negotiation can fall back to half-duplex if the peer is forced to full, leading to mismatch. 📌 Practical Use Case: A PC connected to a switch has poor performance due to a duplex mismatch. 📚 Exam Objective Reference: 2.2 – Duplex 🔁 Follow-Up: How can you resolve duplex mismatches on Cisco devices?

What is the result of enabling jumbo frames? - More frequent STP recalculations - Faster VLAN discovery - Larger Ethernet frames can be transmitted to reduce overhead - Broadcast traffic is blocked

✅ Correct Answer: Larger Ethernet frames can be transmitted to reduce overhead 📘 Explanation: Jumbo frames increase efficiency by allowing more data per frame but require uniform support across the path. 📌 Practical Use Case: A storage system enables jumbo frames for better performance on 10 Gbps links. 📚 Exam Objective Reference: 2.2 – Jumbo Frames 🔁 Follow-Up: What is the typical MTU size for a jumbo frame?

Which scenario best describes a VLAN hopping attack? - An attacker sends double-tagged frames to access a different VLAN - Voice VLAN is reconfigured dynamically - STP is disabled and causes a loop - An attacker uses jumbo frames to overflow buffers

✅ Correct Answer: An attacker sends double-tagged frames to access a different VLAN 📘 Explanation: VLAN hopping takes advantage of misconfigured trunk ports to inject traffic into other VLANs. 📌 Practical Use Case: A compromised device forges 802.1Q tags to jump from VLAN 10 to VLAN 20. 📚 Exam Objective Reference: 2.2 – VLAN/802.1Q 🔁 Follow-Up: How can VLAN hopping be prevented on access ports?

What is the role of the root bridge in Spanning Tree Protocol? - Blocks all trunk ports by default - Routes VLAN traffic - Serves as the central point for calculating the spanning tree topology - Assigns IP addresses to hosts

✅ Correct Answer: Serves as the central point for calculating the spanning tree topology 📘 Explanation: The root bridge is the anchor switch from which all path costs are calculated in STP. 📌 Practical Use Case: A network administrator manually assigns bridge priority to control the STP root bridge. 📚 Exam Objective Reference: 2.2 – Spanning Tree 🔁 Follow-Up: Which STP attribute determines the root bridge?

What happens when multiple switches in a network form a loop without STP? - Broadcast storms and MAC table instability occur - Speed and duplex mismatch - Switches enter VTP transparent mode - Switch ports convert to access mode

✅ Correct Answer: Broadcast storms and MAC table instability occur 📘 Explanation: Without STP, redundant paths result in endless frame forwarding, flooding the network. 📌 Practical Use Case: A new switch added without STP causes the entire LAN to slow down due to looping broadcasts. 📚 Exam Objective Reference: 2.2 – Spanning Tree 🔁 Follow-Up: How can you confirm STP is enabled on a port?

Which parameter must match on both sides of a trunk link for it to function properly? - MAC address table age - Port security settings - Encapsulation type (e.g., 802.1Q) - Switch hostname

✅ Correct Answer: Encapsulation type (e.g., 802.1Q) 📘 Explanation: Trunk ports must agree on the encapsulation method to properly tag and interpret VLAN frames. 📌 Practical Use Case: A trunk link fails to pass VLAN traffic because one side uses ISL and the other uses 802.1Q. 📚 Exam Objective Reference: 2.2 – Trunking 🔁 Follow-Up: What command verifies encapsulation type on a trunk port?

2.2 Flashcards

(31 cards)