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Question 261Question →

An engineer configures a Cisco router interface GigabitEthernet0/0 with a MAC address of 0011.2589.ABCD using the command `ipv6 address 2001:DB8:ACAD:1::/64 eui-64`. Which IPv6 address will be automatically generated on this interface via the EUI-64 process?

Show answer & explanation

Answer: 2001:DB8:ACAD:1:211:25FF:FE89:ABCD

Answer

2001:DB8:ACAD:1:211:25FF:FE89:ABCD
The correct address is constructed by splitting MAC address 0011.2589.ABCD into 0011.25 and 89.ABCD, inserting FFFE into the center to get 0011.25FF.FE89.ABCD, and inverting the 7th bit of the first byte from 0 to 1 (changing 0x00 to 0x02). Appending this interface identifier to prefix 2001:DB8:ACAD:1::/64 yields 2001:DB8:ACAD:1:211:25FF:FE89:ABCD after suppressing leading zeros.

Step-by-Step Solution

1
Split the 48-bit MAC address into two 24-bit halves.
Left half: 00-11-25, Right half: 89-AB-CD.
The EUI-64 process expands a 48-bit MAC address into a 64-bit Interface Identifier by splitting it at the midpoint.
2
Insert the 16-bit hexadecimal constant FFFE between the two halves.
00-11-25-FF-FE-89-AB-CD.
FFFE is inserted into the center of a 48-bit MAC address to construct a 64-bit IEEE EUI-64 interface identifier.
3
Invert the 7th bit (Universal/Local bit) of the first byte.
First byte 0x00 (binary 0000 0000) becomes 0x02 (binary 0000 0010).
Inverting the 7th bit changes a universally administered MAC address bit into a 1 to indicate global uniqueness within IPv6 interface identifiers.
4
Combine the /64 prefix with the generated 64-bit interface identifier and apply standard IPv6 zero suppression.
2001:DB8:ACAD:1:0211:25FF:FE89:ABCD becomes 2001:DB8:ACAD:1:211:25FF:FE89:ABCD.
Leading zeros in any 16-bit hex field must be omitted per standard IPv6 address formatting rules.

Key Concept

IPv6 EUI-64 Interface Identifier Generation
Estimated Time:1m 30s
Question 262Question →

A network engineer is troubleshooting Layer 2 protocol operations between a Cisco Catalyst switch (SW-1) and an adjacent third-party switch (SW-2). The engineer executes the `show lldp neighbors detail` command on SW-1 and reviews the following output:

SW-1# show lldp neighbors detail
------------------------------------------------
Local Interface: Gi1/0/12
Chassis id: 0050.56a1.b2c3
Port id: Eth101/1/5
Port Description: Ethernet101/1/5
System Name: SW-2-AGG
System Description: Vendor-X Enterprise Operating System v8.4
Time remaining: 114 seconds
System Capabilities: B, R
Enabled Capabilities: B
Management Addresses:
IP: 192.168.40.254
Auto Negotiation - supported, enabled
Physical media capabilities:
1000baseT(FD)
VLAN Information:
Native VLAN: 10

Assuming SW-1 port GigabitEthernet1/0/12 is configured as an 802.1Q trunk using default native VLAN 1 and default LLDP timer settings, which diagnosis and remediation step accurately reflect this state?

Show answer & explanation

Answer: A native VLAN mismatch exists because the remote device advertises native VLAN 10 over IEEE 802.1AB TLVs while SW-1 uses native VLAN 1; the native VLAN settings must be synchronized on both switch ports to prevent traffic leakage.

Answer

A native VLAN mismatch exists because the remote device advertises native VLAN 10 over IEEE 802.1AB TLVs while SW-1 uses native VLAN 1; the native VLAN settings must be synchronized on both switch ports to prevent traffic leakage.
The detailed LLDP output explicitly indicates that the remote switch (SW-2-AGG) is sending LLDP Type-Length-Value (TLV) data showing its native VLAN as 10. Since SW-1 is configured with the default native VLAN 1 on its trunk port (Gi1/0/12), a native VLAN mismatch exists across the 802.1Q trunk. Aligning the native VLAN configurations on both connected switch interfaces fixes the mismatch.

Step-by-Step Solution

1
Analyze the local vs remote interface fields in the LLDP output.
Local Interface is GigabitEthernet1/0/12 (on SW-1). Port id/description is Eth101/1/5 (on remote neighbor SW-2-AGG).
Correctly identifying local versus remote identifiers prevents interface role misinterpretation.
2
Evaluate the protocol timers displayed in the output.
'Time remaining: 114 seconds' reflects LLDP's standard holdtime (default 120 seconds = 30s hello × 4 holdtime multiplier).
This confirms that LLDP discovery is operating normally and is not timing out or relying on CDP 180s timers.
3
Examine the Organizationally Specific VLAN TLV output.
The neighbor advertises Native VLAN: 10 via LLDP TLVs, whereas SW-1 uses default native VLAN 1 on trunk Gi1/0/12.
An unmanaged difference in native VLAN configuration across an 802.1Q trunk leads to VLAN hopping vulnerabilities, STP errors, and traffic leakage.

Key Concept

LLDP CLI Output Analysis and Native VLAN Mismatch Detection
Estimated Time:2m 0s
Question 263Question →

A network security analyst is auditing border firewall traffic logs to ensure no unroutable internal addresses are leaked to the public Internet. Corporate security policy requires Network Address Translation (NAT) for all internal devices accessing public web services.

Which TWO IPv4 addresses identified in the firewall log belong to the RFC 1918 private address space and require source NAT before being routed across the public Internet? (Select two.)

Select all that apply

Show answer & explanation

Answer: 10.254.1.5; 172.30.100.45

Answer

The addresses 10.254.1.5 and 172.30.100.45 are RFC 1918 private IPv4 addresses that require Network Address Translation to be routed over the public Internet.
RFC 1918 defines three private IPv4 address blocks that are not routable across the public Internet: 10.0.0.0/8, 172.16.0.0/12 (172.16.0.0 through 172.31.255.255), and 192.168.0.0/16. The address 10.254.1.5 falls inside the 10.0.0.0/8 Class A block, and 172.30.100.45 falls inside the 172.16.0.0/12 Class B block. Both require source NAT to communicate over public networks.

Step-by-Step Solution

1
Identify the standard RFC 1918 private IPv4 address blocks.
Class A: 10.0.0.0/8 (10.0.0.0 – 10.255.255.255)
Class B: 172.16.0.0/12 (172.16.0.0 – 172.31.255.255)
Class C: 192.168.0.0/16 (192.168.0.0 – 192.168.255.255)
RFC 1918 designates these exact prefixes for private enterprise networks and dictates that they are non-routable on the public Internet.
2
Evaluate each address option against the private IPv4 boundary definitions.
10.254.1.5 resides within 10.0.0.0/8.
172.30.100.45 resides within 172.16.0.0/12.
172.32.50.10 is outside 172.16.0.0/12.
192.169.10.1 is outside 192.168.0.0/16.
Addresses starting with 172.32 and 192.169 belong to public IPv4 address space assigned to internet registries.

Key Concept

RFC 1918 Private IPv4 Addressing Ranges
Estimated Time:1m 15s
Question 264Question →

A network administrator needs to select a transport layer protocol for a real-time voice application where low latency is critical and missing packets should not be retransmitted. Which transport layer protocol satisfies these requirements?

Show answer & explanation

Answer: User Datagram Protocol (UDP)

Answer

User Datagram Protocol (UDP) is correct because it operates as a connectionless transport protocol with low header overhead and no retransmission mechanism, preserving low latency for real-time voice data.
User Datagram Protocol (UDP) operates without establishing a session connection or tracking packet delivery. Because it omits sequencing and retransmissions, it minimizes latency, making it the preferred transport layer protocol for time-sensitive traffic like voice and video.

Step-by-Step Solution

1
Identify application requirements
Real-time voice requires minimal latency and minimal overhead, and cannot afford the latency introduced by packet retransmissions.
Voice traffic relies on timely delivery; delayed retransmitted audio packets arrive too late to be usable.
2
Evaluate transport layer protocols
UDP provides lightweight, connectionless transmission without ordering or retransmission guarantees, whereas TCP adds latency via flow control and retransmissions.
UDP headers are only 8 bytes compared to TCP's 20-byte baseline header, eliminating setup handshakes and recovery delays.

Key Concept

Connectionless vs Connection-Oriented Transport Protocols
Question 265Question →

An engineer enters the following configuration command on a Cisco router interface whose hardware MAC address is `0A00.2712.3456`:

`R1(config-if)# ipv6 address 2001:db8:acad:b000::/64 eui-64`

Which fully compressed IPv6 global unicast address will be dynamically assigned to this interface?

Show answer & explanation

Answer: 2001:db8:acad:b000:800:27ff:fe12:3456

Answer

The correct dynamically generated address is 2001:db8:acad:b000:800:27ff:fe12:3456.
To derive the EUI-64 interface identifier from MAC address 0A00.2712.3456, insert FFFE between the 24-bit OUI and 24-bit NIC identifier to get 0A00:27FF:FE12:3456. Invert the 7th bit of the first hex byte (0A = 0000 1010 -> 08 = 0000 1000), resulting in 0800:27FF:FE12:3456. Combining this with prefix 2001:db8:acad:b000::/64 and suppressing the leading zero in 0800 yields 2001:db8:acad:b000:800:27ff:fe12:3456.

Step-by-Step Solution

1
Split MAC address and insert FFFE into the middle
MAC 0A00.2712.3456 becomes 0A00:27FF:FE12:3456.
EUI-64 generation requires expanding a 48-bit MAC address into a 64-bit interface ID by inserting FFFE (0xFFFE) between the OUI and device identifier.
2
Invert the 7th bit (Universal/Local bit) of the first byte
First byte 0A (binary 0000 1010) becomes 08 (binary 0000 1000).
The IEEE standard specifies that the 7th bit of the first byte must be inverted to indicate a globally unique, locally configured IPv6 interface identifier.
3
Combine the subnet prefix and interface ID, applying IPv6 compression rules
2001:db8:acad:b000:0800:27ff:fe12:3456 compresses to 2001:db8:acad:b000:800:27ff:fe12:3456.
Leading zeros within a hextet must be suppressed (0800 becomes 800), while non-zero fields like b000 retain their representation.

Key Concept

EUI-64 Interface Identifier Generation
Estimated Time:2m 0s
Question 266Question →

A network administrator is evaluating the division of responsibilities in a Cisco Split-MAC wireless architecture. Which two functions are performed directly by the Lightweight Access Point (LAP) in real time? (Select two.)

Select all that apply

Show answer & explanation

Answer: Transmitting 802.11 beacon and probe response frames; Executing real-time 802.11 frame encryption and decryption

Answer

The two functions performed directly by the Lightweight Access Point are transmitting 802.11 beacon and probe response frames, and executing real-time 802.11 frame encryption and decryption.
In Cisco Split-MAC architecture, time-sensitive real-time tasks are performed directly by the Lightweight Access Point (LAP). These include transmitting 802.11 beacons, responding to probe requests, and performing hardware encryption/decryption of RF frames. Management, authentication, and global radio management are handled centrally by the WLC.

Step-by-Step Solution

1
Analyze Split-MAC architecture roles
Split-MAC divides 802.11 protocol handling between real-time tasks (LAP) and management/control tasks (WLC).
Real-time functions require immediate RF handling and low latency.
2
Identify LAP real-time tasks
Beacon generation, probe responses, packet buffering, and MAC layer encryption/decryption are handled by the LAP.
These operations must occur instantaneously at the physical RF boundary.
3
Identify WLC centralized management tasks
802.1X authentication, RRM channel/power calculations, and frame payload translation occur at the controller.
Centralizing management provides coordinated control and security enforcement across the wireless network.

Key Concept

Cisco Split-MAC Architecture Function Division
Question 267Question →

A network administrator needs to statically configure an interface on a Cisco Catalyst switch to act as an IEEE 802.1Q trunk link to a neighboring switch. Which interface configuration command achieves this objective?

Show answer & explanation

Answer: switchport mode trunk

Answer

The command `switchport mode trunk` statically sets the switch interface to operate in trunking mode.
The `switchport mode trunk` command puts the interface into permanent trunking mode and initiates DTP negotiation to convert the link into a trunk link.

Step-by-Step Solution

1
Identify the administrative requirement.
The link must be manually configured as a static 802.1Q trunk line connecting two switches.
The scenario requires an interface command that changes the port mode to permanent trunking.
2
Evaluate Cisco IOS interface mode configuration syntax.
Executing `switchport mode trunk` forces the interface to transition out of access mode into permanent 802.1Q trunking mode.
This is the standard command used to establish permanent L2 interswitch connectivity.

Key Concept

802.1Q Trunk Mode Configuration
Question 268Question →

A network administrator needs to segment an enterprise network to prevent broadcast traffic sent by one host from reaching devices in other departments. Which network component natively creates separate broadcast domains at Layer 3?

Show answer & explanation

Answer: Router

Answer

A router natively breaks up broadcast domains because it operates at Layer 3 and blocks Layer 2 broadcast traffic from passing between its interfaces.
Routers operate at Layer 3 (Network Layer) and break up broadcast domains by default because they do not forward Layer 2 broadcast frames between interfaces.

Step-by-Step Solution

1
Analyze the operational requirements specified in the scenario.
The requirement is to isolate broadcast traffic so broadcast frames are not flooded to all hosts.
Broadcast frames flood across all ports within a single broadcast domain.
2
Evaluate the function of Layer 2 vs. Layer 3 network components.
Layer 2 switches separate collision domains but forward broadcasts to all ports in the same VLAN. Routers work at Layer 3 and drop Layer 2 broadcast packets by default.
Routers terminate Layer 2 broadcast domains on each routed interface.

Key Concept

Network Components Roles and Functions
Question 269Question →

Match each Ethernet physical interface standard or transceiver type to its corresponding media specification, wavelength, and maximum distance limitation.

Click a left item, then click its matching right item

Items

10GBASE-SR SFP+ Transceiver
1000BASE-LX Transceiver (operating over MMF)
10GBASE-LR SFP+ Transceiver
100BASE-TX Interface

Matches

Show answer & explanation

Answer

10GBASE-SR SFP+ matches Multimode Fiber using 850 nm wavelength up to 300 m on OM3; 1000BASE-LX over MMF matches Multimode Fiber using 1310 nm wavelength requiring a mode-conditioning patch cord for 550 m reach; 10GBASE-LR SFP+ matches Single-Mode Fiber using 1310 nm wavelength up to 10 km; 100BASE-TX matches Category 5e/6 UTP Copper cable up to 100 m.
Each physical transceiver and interface type has specific operating wavelengths, core media requirements, and distance bounds: 10GBASE-SR uses 850 nm lasers on multimode fiber up to 300 meters (OM3); 1000BASE-LX can run over multimode fiber at 1310 nm up to 550 meters when using a mode-conditioning patch cord; 10GBASE-LR operates over 1310 nm single-mode fiber up to 10 kilometers; and 100BASE-TX uses twisted-pair copper with RJ-45 connectors up to 100 meters.

Step-by-Step Solution

1
Identify copper media standards among the options
Classify 100BASE-TX as unshielded twisted-pair (UTP) copper media operating up to 100 meters with RJ-45 terminations.
The suffix -TX in IEEE 802.3 standards denotes twisted-pair copper specifications.
2
Differentiate 10 Gigabit optical transceiver specifications
Pair 10GBASE-SR with 850 nm multimode fiber (300m reach on OM3) and 10GBASE-LR with 1310 nm single-mode fiber (10 km reach).
Short Range (-SR) optics rely on lower-cost 850 nm VCSEL lasers for multimode cores, whereas Long Range (-LR) optics require 1310 nm Fabry-Perot/DFB lasers for single-mode fiber.
3
Analyze legacy Gigabit Ethernet deployment nuances over MMF
Associate 1000BASE-LX operating on legacy MMF with the mode-conditioning patch cord requirement to reach 550 meters.
Coupling a single-mode laser directly into the center of a multimode fiber core causes multiple light modes to propagate asynchronously (differential mode delay), which is corrected by offset laser launch via a mode-conditioning patch cord.

Key Concept

Physical Interface, Fiber Optics, and Cabling Specifications
Estimated Time:2m 0s
Question 270Question →

A network engineer is designing a collapsed core enterprise campus topology connecting multiple access switches to a redundant pair of core switches. The design requires all redundant uplink interfaces from each access switch to forward traffic simultaneously for bandwidth optimization and load balancing, while preventing Layer 2 loops without forcing Spanning Tree Protocol (STP) to place any physical uplink into a blocking state. Which design architecture or technology satisfies these operational requirements?

Show answer & explanation

Answer: Implementation of multichassis link aggregation (such as Cisco StackWise or Virtual Switching System) across the collapsed core switches

Answer

Implementation of multichassis link aggregation (such as Cisco StackWise or Virtual Switching System) across the collapsed core switches
In a 2-Tier Collapsed Core architecture, dual core switches operating independently would trigger Spanning Tree Protocol (STP) to block one of the redundant uplinks from each access switch to prevent Layer 2 loops. By deploying multichassis technologies such as Cisco StackWise, Virtual Switching System (VSS), or StackWise Virtual, the two core switches merge into a single logical control plane. This enables access switches to configure Multi-chassis EtherChannel (MEC), allowing all redundant physical uplinks to actively forward traffic simultaneously with balanced load distribution.

Step-by-Step Solution

1
Identify topology requirements
The topology is a 2-Tier Collapsed Core model requiring redundant uplinks from access switches to dual core switches with active-active forwarding (no STP blocked ports).
Standard STP blocks redundant paths to prevent loops, reducing aggregate bandwidth if links are unaggregated.
2
Evaluate switch virtualization and aggregation mechanisms
Multichassis technology presents dual core switches as a single logical STP bridge.
Because the access switch sees only one logical upstream device, cross-chassis EtherChannel (MEC/LACP) bundles all physical links into a single logical channel.
3
Confirm operational behavior
Traffic is load balanced across all links in the EtherChannel bundle while STP views the bundle as a single loop-free connection.
This achieves full bandwidth efficiency and instantaneous hardware-based failover.

Key Concept

Collapsed Core Topology & Multichassis EtherChannel (MEC / VSS / StackWise)
Estimated Time:2m 0s
Question 271Question →

SwitchA has its interconnecting physical interfaces configured with the command `channel-group 1 mode passive`. Which channel-group mode must be configured on SwitchB for the IEEE 802.3ad LACP EtherChannel to successfully form?

Show answer & explanation

Answer: `active`

Answer

The mode configured on SwitchB must be `active`.
The `active` mode causes the switch port to actively initiate negotiations by sending LACP frames. Since SwitchA is configured as `passive`, it only responds to received LACP frames. SwitchB must be in `active` mode so LACP frames are transmitted to start the dynamic trunk negotiation.

Step-by-Step Solution

1
Analyze the LACP mode configured on SwitchA.
SwitchA is set to `passive`, meaning it responds to LACP packets but will not initiate LACP frame exchanges.
LACP passive mode requires an incoming LACP negotiation request to begin bundling interfaces.
2
Determine the compatible LACP mode required on SwitchB.
SwitchB must be set to `active` so that it actively transmits LACP control frames to SwitchA.
At least one end of an LACP EtherChannel link must be in `active` mode for successful negotiation.

Key Concept

LACP Mode Compatibility
Question 272Question →

Match each network topology architecture on the left with its primary design characteristic on the right.

Click a left item, then click its matching right item

Items

Collapsed Core Architecture
Three-Tier Campus Architecture
Spine-Leaf Data Center Architecture
SOHO Network Architecture

Matches

Show answer & explanation

Answer

Collapsed Core Architecture pairs with combining core and distribution functions into a single tier. Three-Tier Campus Architecture pairs with using distinct Access, Distribution, and Core layers. Spine-Leaf Data Center Architecture pairs with providing predictable, low-latency east-west traffic flow. SOHO Network Architecture pairs with integrating routing, switching, wireless, and security into a single appliance.
Each topology architecture serves a distinct deployment scale and traffic profile. Collapsed Core simplifies management by consolidating distribution and core functions. Three-Tier provides clear boundary separation across large campuses. Spine-Leaf ensures low, uniform latency across data center workloads. SOHO designs consolidate multi-layer functions into a single physical appliance for small sites.

Step-by-Step Solution

1
Identify the structural definition of Collapsed Core architecture.
Collapsed Core merges the distribution and core layers into a single switch tier.
Smaller campus sites do not require a separate dedicated core layer, making a two-tier collapsed design more cost-effective.
2
Identify the structural definition of Three-Tier Campus architecture.
Three-Tier relies on dedicated Access, Distribution, and Core layers.
Large multi-building campus networks require modular tier separation for traffic control, policy enforcement, and scalability.
3
Identify the structural definition of Spine-Leaf Data Center architecture.
Spine-Leaf provides deterministic east-west latency with all leaf switches directly connected to all spine switches.
Modern data center applications generate significant server-to-server traffic, requiring consistent hop counts and ECMP routing.
4
Identify the structural definition of Small Office/Home Office (SOHO) network architecture.
SOHO architectures use a single multi-function wireless router appliance.
SOHO environments have very low user counts and simple connectivity demands handled by integrated consumer or small-business devices.

Key Concept

Enterprise Network Topology Architectures
Question 273Question →

A host in VLAN 20 sends an Ethernet frame to another host in VLAN 20 located on a remote switch across an IEEE 802.1Q trunk link. What is the correct chronological sequence of events for processing and forwarding this frame from the source access port to the destination access port?

Drag items to arrange them in the correct order

Show answer & explanation

Answer

The correct chronological sequence begins with Switch 1 receiving the untagged frame on an access port, inserting a 4-byte 802.1Q tag for VLAN 20, transmitting the tagged frame over the trunk, Switch 2 receiving and identifying the tagged frame, Switch 2 stripping the 802.1Q header, and finally delivering the untagged frame to the destination host on the access port.
The correct sequence follows standard IEEE 802.1Q trunking operations: frames enter an access port untagged, are tagged with a 4-byte header containing the VLAN ID when forwarded out a trunk port for non-native VLANs, travel across the link, are read and stripped of the tag by the remote switch, and are finally delivered untagged to the destination host on an access port in the same VLAN.

Step-by-Step Solution

1
Identify frame ingress at the source switch
The source switch accepts an untagged frame on a standard VLAN 20 access port.
End-user hosts send standard Ethernet frames without 802.1Q tags.
2
Apply 802.1Q tagging prior to trunk egress
A 4-byte 802.1Q tag with VLAN ID 20 is inserted into the Ethernet header.
Trunk links require frame tagging to distinguish traffic belonging to non-native VLANs across switches.
3
Transmit the tagged frame across the trunk
The frame travels over the physical interswitch link.
The frame carries the VLAN 20 identifier across the shared trunk interface.
4
Process frame ingress at the receiving switch
Switch 2 reads the 802.1Q tag to determine the target VLAN.
The receiving switch relies on the tag to route the frame internally within the correct VLAN context.
5
De-encapsulate the 802.1Q frame
The 4-byte 802.1Q header is stripped from the frame.
Standard access ports must not send tagged frames to end hosts that do not support 802.1Q tagging.
6
Forward untagged frame to destination host
The original frame is delivered out the destination VLAN 20 access port.
The destination host receives standard Ethernet traffic identical to what was originally transmitted.

Key Concept

802.1Q Frame Tagging and Trunk Processing Lifecycle
Estimated Time:1m 0s
Question 274Question →

An administrator reviews the routing table of a Cisco router and observes the following specific route entry:

text
O 172.31.50.0/26 [110/65] via 10.1.1.2, 00:04:12, GigabitEthernet0/1

Which two statements correctly interpret the components of this routing entry? (Select two.)

Select all that apply

Show answer & explanation

Answer: The administrative distance of this route is 110, identifying OSPF as the routing protocol source.; The metric value for reaching the destination network via this path is 65.

Answer

The statement identifying the administrative distance as 110 (indicating OSPF) and the statement identifying the metric value as 65 are correct.
In Cisco IOS routing tables, a route entry displays the route source code ('O' for OSPF), destination subnet prefix, and bracketed values [Administrative Distance / Metric]. For the route entry provided, 110 is the Administrative Distance and 65 is the OSPF route metric. The egress interface is GigabitEthernet0/1, and 10.1.1.2 is the next-hop router IP address.

Step-by-Step Solution

1
Analyze the prefix code prefixing the routing entry.
The code 'O' indicates the route was dynamically learned through Open Shortest Path First (OSPF).
Routing codes at the beginning of an entry indicate the source protocol.
2
Examine the bracketed numbers [110/65].
The structure is formatted as [Administrative Distance / Metric]. Therefore, AD = 110 and Metric = 65.
Cisco IOS routing entries consistently format believable path trustworthiness (AD) first and protocol metric second.
3
Identify destination subnet and forwarding descriptors.
172.31.50.0/26 is the target subnet, 10.1.1.2 is the next-hop IP address, and GigabitEthernet0/1 is the egress interface.
The 'via' keyword introduces the next-hop IP address for remote networks.

Key Concept

Routing Table Components
Question 275Question →

A network administrator is configuring Hot Standby Router Protocol (HSRP) on a Cisco router interface that has already been assigned the physical IPv4 address 192.168.10.1/24. The administrator attempts to execute the command `standby 1 ip 192.168.10.1` on this interface. What is the result of executing this command?

Show answer & explanation

Answer: The router rejects the command because HSRP does not permit assigning a router's physical interface IP address as the virtual IP address.

Answer

The router rejects the command because HSRP does not permit assigning a router's physical interface IP address as the virtual IP address.
In Hot Standby Router Protocol (HSRP), the virtual IP address must be an unused, unique IP address within the local IPv4 subnet. Unlike Virtual Router Redundancy Protocol (VRRP), which allows the virtual IP address to match a physical interface IP address (making that router the IP address owner with priority 255), HSRP explicitly forbids using any member router's physical interface IP address. Attempting to do so in Cisco IOS results in an error message rejecting the command.

Step-by-Step Solution

1
Identify the protocol being configured and the requested virtual IP address.
The protocol is HSRP (v1/v2) and the command `standby 1 ip 192.168.10.1` attempts to use the physical IP address of the local interface (192.168.10.1).
Determining protocol-specific rules for Virtual IP (VIP) assignment is required to evaluate command validity.
2
Recall HSRP IP address assignment constraints.
HSRP requires the virtual IP address to be an unused IP address within the subnet shared by the gateway routers.
HSRP does not support the concept of an IP address owner sharing a physical IP address with the virtual IP address.
3
Determine the Cisco IOS CLI output behavior.
Cisco IOS generates an error indicating that the virtual IP address cannot match the interface IP address and rejects the command.
Executing a standby IP command with the interface's own IP address fails validation.

Key Concept

HSRP Virtual IP Address Assignment Constraints
Question 276Question →

An access port on a Cisco switch running IEEE 802.1D Spanning Tree Protocol (STP) without PortFast enabled is connected to a workstation and experiences a link-up event. Arrange the operational STP port states in the exact sequential order that the interface undergoes from initial link activation until it actively processes and forwards user data traffic.

Drag items to arrange them in the correct order

Show answer & explanation

Answer

The correct operational sequence of 802.1D STP port states from link activation to active forwarding is: Blocking state, Listening state, Learning state, and Forwarding state.
IEEE 802.1D Spanning Tree Protocol transitions non-PortFast interfaces through a mandatory four-stage sequence: Blocking (loop prevention), Listening (BPDU exchange and port role determination), Learning (building MAC tables), and Forwarding (active user frame transmission).

Step-by-Step Solution

1
Identify the initial default safety state upon link bring-up in classic IEEE 802.1D STP.
The port enters the Blocking state immediately upon physical link detection.
Default 802.1D STP behavior forces a non-PortFast interface into Blocking to prevent immediate Layer 2 loop creation.
2
Determine the state where active BPDU negotiation and role determination occur.
The port transitions from Blocking to the Listening state for a duration of 15 seconds.
In Listening, the switch transmits and processes BPDUs to determine active topology roles, while suppressing MAC table learning and user data frame forwarding.
3
Identify the state dedicated to populating switch address tables prior to data forwarding.
The port transitions from Listening to the Learning state for a duration of 15 seconds.
In Learning, the port populates its MAC address table from incoming frame source MACs to prevent unnecessary unicast flooding when data forwarding starts.
4
Identify the final fully functional operational state.
The port transitions from Learning into the Forwarding state.
After the total 30-second convergence delay (2 x 15-second Forward Delay timers) completes without topology conflicts, the interface begins normal frame forwarding.

Key Concept

IEEE 802.1D STP Port State Transition Sequence
Question 277Question →

Which two statements accurately describe port roles, states, and configuration rules in Rapid PVST+? (Select two choices.)

Select all that apply

Show answer & explanation

Answer: An Alternate port provides a backup path to the Root Bridge and remains in the discarding state under normal operation.; Rapid PVST+ removes the 802.1D Listening port state and consolidates non-forwarding states into the Discarding state.

Answer

The correct statements are that an Alternate port provides a backup path to the Root Bridge while remaining in a discarding state, and that Rapid PVST+ eliminates the 802.1D Listening state by using the Discarding state.
Rapid PVST+ introduces the Alternate port role, which provides an instant backup path to the Root Bridge while staying in a discarding state. Additionally, Rapid PVST+ streamlines the IEEE 802.1D port states (Disabled, Blocking, Listening, Learning, Forwarding) down to three operational states: Discarding, Learning, and Forwarding.

Step-by-Step Solution

1
Evaluate the role of an Alternate port in Rapid PVST+.
Confirm that an Alternate port receives BPDUs from another switch and acts as an alternate path to the Root Bridge in the discarding state.
RSTP/Rapid PVST+ defines Alternate ports for fast convergence when a Root port link fails.
2
Evaluate Rapid PVST+ operational port states.
Identify that 802.1w simplifies port states to Discarding, Learning, and Forwarding, combining Disabled, Blocking, and Listening into Discarding.
This structural simplification enables faster overall protocol operation.
3
Verify bridge priority increments and PortFast guidelines.
Reject custom non-multiplier priority values and reject applying PortFast on switch interconnects.
Priority values must adhere to steps of 4096 due to the System ID Extension, and PortFast is reserved exclusively for edge access interfaces.

Key Concept

Rapid PVST+ Port Roles, States, and Priority Calculations
Question 278Question →

A network administrator needs to perform initial configuration and out-of-band management on a newly deployed Cisco Wireless LAN Controller (WLC). Which WLC interface is specifically dedicated to out-of-band management and network recovery, operating completely isolated from the data traffic processing plane?

Show answer & explanation

Answer: Service Port

Answer

The Service Port is the dedicated physical interface reserved for out-of-band management, system restoration, and initial setup on a Cisco WLC.
The Service Port is a dedicated physical port on Cisco Wireless LAN Controllers that provides isolated, out-of-band management capabilities. It operates on its own discrete subnet and interface, allowing administrators to access the controller for initial setup, troubleshooting, or recovery even when the main network links or distribution switches are offline.

Step-by-Step Solution

1
Identify out-of-band management requirements for Cisco WLC architectures.
Recognize that out-of-band traffic must be physically segregated from the in-band data paths and distribution switch ports.
Out-of-band access ensures administrative connectivity remains operational even during network outages affecting main data VLANs.
2
Differentiate between WLC interfaces based on their functional roles.
The Service Port handles out-of-band management, the Management Interface handles in-band management and CAPWAP control, Virtual Interface handles web auth/DHCP relay, and Dynamic Interfaces handle WLAN client traffic.
Cisco controllers separate administrative control planes across distinct physical and logical interfaces.

Key Concept

Cisco WLC Physical and Logical Interface Roles
Question 279Question →

Place the tie-breaking criteria evaluated by a non-root switch running Rapid PVST+ in the correct sequence (from first evaluated to last evaluated) when selecting its Root Port.

Drag items to arrange them in the correct order

Show answer & explanation

Answer

The correct sequence for Rapid PVST+ Root Port selection tie-breaking is: 1) Lowest cumulative Root Path Cost, 2) Lowest Designated (Sender) Bridge ID, 3) Lowest Designated (Sender) Port ID, and 4) Lowest Local Port ID on the receiving switch.
Rapid PVST+ evaluates Root Port selection strictly in sequence: cumulative path cost first, followed by upstream sender Bridge ID, upstream sender Port ID, and finally the local receiving Port ID as a last resort.

Step-by-Step Solution

1
Identify the primary criterion for Root Port selection in Spanning Tree operations.
Path cost evaluation is performed first.
The switch determines the shortest administrative distance to the Root Bridge by adding the local port cost to the root path cost reported in the incoming BPDU.
2
Evaluate the first tie-breaker if path costs are equal.
Designated (Sender) Bridge ID is evaluated.
When equal-cost paths originate from different neighboring switches, the switch prefers the neighbor with the lowest Bridge ID (Priority + System ID Extension + MAC Address).
3
Evaluate the second tie-breaker if receiving BPDUs from the same neighbor across parallel links.
Designated (Sender) Port ID is evaluated.
When parallel links connect to the same upstream switch, the neighbor Bridge ID is identical, so the sender's Port ID (Port Priority + Port Number) breaks the tie.
4
Evaluate the final tie-breaker if BPDUs arrive on different local interfaces from the exact same remote port.
Local Port ID is evaluated.
If all sender parameters are identical, the local receiving switch uses its own lowest Port ID (Port Priority + Port Number) as the definitive tie-breaker.

Key Concept

Rapid PVST+ Root Port Selection Algorithm
Question 280Question →

Match each Cisco Wireless LAN Controller (WLC) interface type to its corresponding primary function.

Click a left item, then click its matching right item

Items

Management Interface
Service Port
Virtual Interface
Dynamic Interface

Matches

Show answer & explanation

Answer

Management Interface matches in-band access and CAPWAP termination; Service Port matches out-of-band recovery management; Virtual Interface matches mobility management, DHCP relay, and web auth; Dynamic Interface matches user VLAN data mapping.
Each WLC interface has a distinct architectural purpose: the Management Interface is responsible for in-band administration and CAPWAP tunnel termination; the Service Port is isolated for out-of-band maintenance; the Virtual Interface facilitates client web auth and DHCP relaying; and Dynamic Interfaces handle user data mapping to trunked VLANs.

Step-by-Step Solution

1
Identify in-band management and CAPWAP termination requirements
The Management Interface handles in-band administrative traffic and CAPWAP communications with APs.
Lightweight Access Points terminate CAPWAP control and data tunnels on the WLC management interface.
2
Identify out-of-band administrative access requirements
The Service Port provides dedicated, isolated out-of-band access.
The service port is non-routable and independent of the main data path for out-of-band management and recovery.
3
Differentiate between Virtual and Dynamic internal interfaces
Virtual interface manages web auth/DHCP relaying, while Dynamic interfaces bind WLANs to user VLANs.
Virtual interface provides internal Layer 3 services to clients, whereas Dynamic interfaces handle client payload forwarding.

Key Concept

Cisco Wireless LAN Controller Interfaces and Management Connections
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