CCNA Network Implementation Questions

STP prevents loops in a network but does not tag frames with VLAN information; it operates at Layer 2 to block redundant paths, not to identify VLAN membership.

VTP is used to synchronize VLAN information across switches, not to tag frames with VLAN information. The protocol for tagging frames is 802.1Q.

LACP is used for link aggregation (combining multiple physical links into one logical link) to increase bandwidth and provide redundancy, not for tagging frames with VLAN information.

Cat6a twisted-pair copper is limited to 100 meters for 10GBASE-T and 1GBASE-T, so it cannot reach 150 meters. The question requires a link of 150 meters, making Cat6a unsuitable.

Single-mode fiber optic is more expensive than multimode fiber and is typically used for longer distances (several kilometers), making it overkill and over budget for a 150-meter link.

802.1X is an authentication framework used for port-based network access control, not a roaming standard. It requires re-authentication when roaming between access points unless combined with a fast roaming protocol like 802.11r.

802.11i (WPA2) provides security (encryption and authentication) but does not handle fast roaming without re-authentication to the authentication server. The question specifically asks for a standard that allows clients to roam without re-authenticating, which is addressed by 802.11r (Fast Roaming).

802.11e defines QoS enhancements for wireless networks, not fast roaming or authentication caching. The question asks for a standard that allows clients to roam without re-authenticating, which is addressed by 802.11r, not 802.11e.

Single-mode fiber with 1000BASE-LX can reach 400 meters, but multimode fiber with 1000BASE-SX is more cost-effective for this distance and is designed for shorter runs with high EMI. Single-mode fiber and transceivers are more expensive, making option A less cost-effective.

10GBASE-SR transceivers are designed for 10 Gbps speeds, which is overkill for a 400-meter link and more expensive than 1000BASE-SX. Additionally, multimode fiber with 10GBASE-SR typically supports distances up to 300 meters (OM3) or 400 meters (OM4) at 10 Gbps, but the question asks for a cost-effective solution, and 10GBASE-SR is not cost-effective for 1 Gbps needs.

1000BASE-EX transceivers are designed for single-mode fiber and support distances up to 40 km, which is overkill and more expensive for a 400-meter link. Multimode fiber with 1000BASE-SX is more cost-effective for this distance.

A /27 subnet provides 2^(32-27)-2 = 30 usable host addresses, which is insufficient for the requirement of 50 usable hosts.

A /28 subnet provides only 14 usable host addresses (2^(32-28)-2 = 14), which is insufficient for the required 50 usable hosts.

A /25 subnet provides 126 usable host addresses, which far exceeds the requirement of 50. The question asks for the minimum number of usable addresses while still accommodating the requirement, so /26 (62 usable) is the correct choice, not /25.

Incorrect termination can cause signal loss, but the question states the fiber is multimode and the distance is 2 km. Multimode fiber is typically limited to about 550 meters at 10 Gbps; the primary issue is attenuation due to exceeding the distance limit, not termination.

Crosstalk occurs when signals from adjacent cables interfere with each other, typically in copper cabling (e.g., UTP). Fiber optic cables use light, not electricity, so crosstalk is not a concern, especially over a 2 km multimode link where distance-related attenuation is the primary issue.

The tunnel is active and IPsec traffic is permitted, so DNS is not the issue. The problem is that the branch office cannot reach the main office subnet, which indicates a routing problem, not DNS resolution.

The tunnel is active, indicating IPsec is working; MTU issues typically cause fragmentation or packet loss, not complete unreachability between subnets.

The SSID is a wireless network identifier for Wi-Fi, which is unrelated to IPsec site-to-site VPN connectivity between branch and main office networks.

Configuring a VTY password is necessary for remote access, but the switch must first have an IP address on the management VLAN to be reachable over the network. Without IP connectivity, SSH cannot be established.

10GBASE-SR over multimode fiber is limited to distances around 300-400 meters (depending on OM3/OM4), so it cannot reliably support 450 meters. Single-mode fiber with 10GBASE-LR is required for that distance at 10 Gbps.

1000BASE-LX supports only 1 Gbps, while the question asks for the highest data rate over 450 meters. 10GBASE-LR provides 10 Gbps, which is higher.

OSPF can dynamically assign a router ID using the highest loopback or physical IP address if none is configured, so missing a router ID would not prevent routes from another area from appearing.

A corrupted link-state database would typically cause OSPF neighbor states to not reach FULL or cause routing loops, not specifically prevent routes from another area from appearing while neighbors are FULL.

RIP uses hop count as its metric, not bandwidth and delay, and converges slowly due to its periodic updates and hold-down timers. It also does not support VLSM in RIPv1, though RIPv2 does, but it still lacks the required metric and fast convergence.

OSPF uses cost as its metric, which is typically based on bandwidth but not delay. The question requires a metric based on both bandwidth and delay, which is a feature of EIGRP, not OSPF.

BGP uses a path-vector algorithm with complex attributes like AS-path, not bandwidth and delay, and converges slowly, making it unsuitable for this internal routing scenario requiring fast convergence and VLSM support.

802.11ac is a wireless networking standard for Wi-Fi, not a Power over Ethernet (PoE) standard. It does not define power delivery over Ethernet cables.

802.1X is an authentication protocol for network access control, not a standard for powering devices over Ethernet. The question asks for a standard that provides power over Ethernet, which is addressed by IEEE 802.3af (PoE).

802.3ab defines Gigabit Ethernet over copper (1000BASE-T), not Power over Ethernet (PoE). It does not provide power delivery.

LACP 'On' mode (also called manual or static) does not use LACP negotiation; it forces the link into a LAG without exchanging LACP frames. Since Switch A is in LACP active mode, Switch B must be in LACP passive mode to successfully negotiate the LAG via LACP.

In this question, LACP is explicitly used (Switch A is in active mode), so the peer must use LACP passive mode. 'Static' is not a valid LACP mode; it refers to a manual LAG without LACP, which would not interoperate with LACP active.

In LACP, 'Auto' is a Cisco proprietary mode that initiates negotiation only if the remote side is set to 'Desirable'. Since Switch A is in LACP 'Active' mode, Switch B must be in LACP 'Passive' mode to form a LAG; 'Auto' is not a valid LACP mode.

Spanning tree priority is a configuration for the Spanning Tree Protocol (STP) to influence root bridge election, not for enabling remote management of the switch's management interface.

VLAN 1 membership is the default for all switch ports and does not enable remote management; remote management requires an IP address and default gateway on the management interface.

Port security is a feature that restricts which MAC addresses can communicate through a switch port, but it is not required for remote management of the switch's management interface.

PVC-jacketed cable is not allowed in plenum spaces because it produces toxic smoke and supports flame propagation, violating building codes that require low-smoke, fire-resistant materials.

Riser-rated cable is designed for vertical runs between floors, not for plenum spaces where air circulates. Building codes require plenum-rated cable in plenums due to its low smoke and flame spread properties.

LSZH cable is designed to emit low smoke and no halogens when burned, but it is not specifically rated for plenum spaces; plenum-rated cable is required by building codes for air-handling spaces due to its fire-resistant and low-smoke properties.

QoS marking for classification and prioritization uses Layer 3 fields like DSCP or IP Precedence, not the source IP address. The source IP identifies the sender but does not carry QoS priority information.

Source port number is a transport-layer field used for identifying applications, but QoS marking for voice traffic is typically done at Layer 3 using DSCP (e.g., EF for voice), not by source port.

MAC addresses operate at Layer 2 and are not used for QoS marking in IP networks; QoS classification and prioritization rely on Layer 3 fields like DSCP or IP precedence.

802.1X is a port-based network access control protocol used for authentication, not for tagging frames with VLAN information. It does not provide VLAN tagging capabilities.

802.11 is a wireless networking standard (Wi-Fi), not a protocol for tagging VLAN frames on Ethernet links between switches.

802.3 is an Ethernet standard that defines physical and data link layer specifications, but it does not include VLAN tagging. VLAN tagging is accomplished by 802.1Q, which inserts a VLAN tag into the Ethernet frame.