350-401 Practice Test 15 — 15 Questions

Question 1

Examine the following configuration:

interface Port-channel1
 switchport mode trunk
!
interface GigabitEthernet0/1
 switchport mode trunk
 channel-group 1 mode desirable
!
interface GigabitEthernet0/2
 switchport mode access
 channel-group 1 mode desirable

What is the problem with this configuration?

Accepted Answer

The switchport mode mismatch between Gi0/1 (trunk) and Gi0/2 (access) will prevent the EtherChannel from forming.. EtherChannel requires all member interfaces to have the same switchport mode (all trunk or all access). Here, Gi0/1 is configured as trunk, but Gi0/2 is configured as access. This mismatch will prevent the channel from forming.

Answer

The channel-group mode desirable is incompatible with trunk ports.

Answer

The port-channel interface must also be configured as access to match Gi0/2.

Answer

The EtherChannel will form but only Gi0/1 will be active.

Question 2

Examine the following configuration:

interface Port-channel1
 switchport mode trunk
!
interface GigabitEthernet0/1
 switchport mode trunk
 channel-group 1 mode active
 spanning-tree portfast
!
interface GigabitEthernet0/2
 switchport mode trunk
 channel-group 1 mode active
 spanning-tree portfast

What is the effect of the 'spanning-tree portfast' command on the member interfaces of this EtherChannel?

Accepted Answer

The PortFast on the member interfaces will be ignored because they are part of an EtherChannel.. PortFast is used on access ports to immediately transition to forwarding state, bypassing STP listening/learning. However, on trunk ports, PortFast can cause loops if used incorrectly. In this case, the member interfaces are part of an EtherChannel, and PortFast is applied at the interface level. But the port-channel interface itself does not have PortFast. The PortFast on member interfaces is ignored because the channel is a trunk; the port-channel interface controls STP. The correct practice is to apply PortFast on the port-channel interface, not on individual members.

Answer

The PortFast will be applied to the EtherChannel, causing it to immediately transition to forwarding.

Answer

The PortFast will cause the EtherChannel to form faster.

Answer

The configuration will cause a spanning-tree loop because PortFast is used on trunk ports.

Question 3

What is the maximum number of active member links supported in a single EtherChannel on Cisco Catalyst switches?

Accepted Answer

8. Cisco Catalyst switches support up to 8 active member links in a single EtherChannel. Some platforms also support up to 16 links with 8 active and 8 standby using LACP, but the maximum active links is 8.

Answer

4

Answer

16

Answer

32

Question 4

Consider this configuration:

interface Port-channel1
 switchport mode trunk
 switchport trunk native vlan 999
!
interface GigabitEthernet0/1
 switchport mode trunk
 switchport trunk native vlan 999
 channel-group 1 mode active
!
interface GigabitEthernet0/2
 switchport mode trunk
 switchport trunk native vlan 999
 channel-group 1 mode active

What is the effect of the 'switchport trunk native vlan 999' command on the EtherChannel?

Accepted Answer

The EtherChannel will use VLAN 999 as the native VLAN, and any untagged frames will be associated with VLAN 999.. The native VLAN is used for untagged traffic on a trunk. Setting it to 999 (an unused VLAN) helps prevent VLAN hopping attacks and ensures that any untagged frames are dropped. The configuration is consistent across all member interfaces and the port-channel, so the channel will form.

Answer

The EtherChannel will drop all untagged frames because the native VLAN is not in the allowed list.

Answer

The EtherChannel will not form because the native VLAN must be the same across all interfaces, which it is.

Answer

The EtherChannel will form but the native VLAN will be ignored on the port-channel.

Question 5

What is the default load-balancing method used by Cisco switches for EtherChannel?

Accepted Answer

Source MAC address. Cisco switches default to source MAC address-based load balancing for EtherChannel. This method distributes traffic based on the source MAC address of the frame, which can lead to uneven distribution if traffic patterns are not diverse.

Answer

Destination MAC address

Answer

Source IP address

Answer

Source and destination IP address

Question 6

Which LACP mode must be configured on at least one side of an EtherChannel for the channel to establish?

Accepted Answer

Active. LACP requires at least one side to be in active mode to initiate negotiation. If both sides are passive, the channel will not form because neither side sends LACP packets.

Answer

Passive

Answer

Desirable

Answer

On

Question 7

A large enterprise has a campus network with a collapsed core design. The core switch connects to two distribution switches, each serving several access switches. The network uses OSPF as the IGP. Recently, after a link failure between the core and distribution switch A, the network experienced a 30-second outage before converging. The engineer wants to improve convergence time to under 5 seconds. The budget is limited, so hardware upgrades are not an option. The engineer is considering the following actions:
A. Enable OSPF Fast Hello on all interfaces.
B. Reduce OSPF dead timer to 1 second and hello timer to 333 milliseconds.
C. Implement OSPF LSA throttling with a minimum interval of 0 ms.
D. Use OSPF incremental SPF (iSPF).

Which action will provide the most significant improvement in convergence time for this scenario?

Accepted Answer

Reduce OSPF dead timer to 1 second and hello timer to 333 milliseconds.. Option B is correct because reducing the OSPF dead timer to 1 second and hello timer to 333 milliseconds directly addresses the 30-second outage caused by the link failure. The default dead timer (40 seconds on broadcast networks) is the primary contributor to convergence delay, as OSPF must wait for the dead interval to expire before declaring a neighbor down. By lowering these timers, failure detection drops from 40 seconds to approximately 1 second, which is the most impactful single change for convergence under budget constraints.

Answer

Enable OSPF Fast Hello on all interfaces.

Answer

Implement OSPF LSA throttling with a minimum interval of 0 ms.

Answer

Use OSPF incremental SPF (iSPF).

Question 8

A network engineer is deploying a new wireless LAN controller (WLC) in a campus network. The WLC must manage 200 access points across three buildings. The engineer configures the WLC with a management IP address and enables CAPWAP. However, the access points fail to join the WLC. The APs are in the same VLAN as the WLC and can ping the WLC's management IP. What is the most likely cause of the APs not joining?

Accepted Answer

The WLC does not have a CAPWAP source interface configured.. The correct answer is that the APs are unable to discover the WLC via CAPWAP because the WLC's CAPWAP source interface is not configured or is misconfigured. Even though the APs can ping the management IP, CAPWAP discovery requires the WLC to respond from a consistent source IP. The other options are less likely: DHCP option 43 is not needed if APs are in the same subnet, APs do not need a specific IOS version to join, and APs do not need a static IP if they can obtain one via DHCP.

Answer

The APs are not configured with DHCP option 43 to point to the WLC.

Answer

The APs are running an incompatible IOS version that does not support CAPWAP.

Answer

The APs must be assigned a static IP address to join the WLC.

Question 9

An engineer is configuring a new Cisco 9800 WLC in a branch office. The WLC will manage 50 APs and must provide guest access with a captive portal. The engineer configures a guest SSID with open authentication and a redirect ACL for the captive portal. However, after the configuration, clients can associate to the guest SSID but cannot reach the captive portal page. What is the most likely cause?

Accepted Answer

The redirect ACL is missing entries for DNS and HTTP traffic to the captive portal server.. The correct answer is that the redirect ACL is not properly configured to allow DNS and HTTP traffic to the captive portal server. Without proper ACL entries, the client's HTTP request is not redirected to the portal. The other options are incorrect because open authentication does not require a pre-shared key, the WLC does not need a specific interface for guest traffic (it can use a service port or management interface), and captive portal does not require RADIUS authentication by default.

Answer

The guest SSID is configured with open authentication, which does not support captive portal.

Answer

The WLC does not have a dedicated guest interface configured.

Answer

The captive portal requires a RADIUS server to be configured on the WLC.

Question 10

Drag and drop the steps of LACP EtherChannel negotiation and bundle formation into the correct order, from first to last.

Accepted Answer

Exchange LACP system priority to elect active side. LACP first exchanges system priority to determine which side is active, then exchanges port priorities to select which ports bundle, next negotiates the operational key, then forms the bundle by synchronizing parameters, and finally the port channel interface becomes operational. This order follows the LACP state machine as defined in IEEE 802.3ad.

Question 11

A company is deploying a new wireless network in a large warehouse. The network engineer must choose between using a centralized WLC architecture (with CAPWAP tunnels) or a converged access (SD-Access) wireless architecture. The warehouse has high-density client areas and requires low latency for real-time applications like voice and video. Which architecture should the engineer choose and why?

Accepted Answer

Converged access (SD-Access) wireless, because it allows local switching of traffic at the access layer, reducing latency.. The correct answer is converged access (SD-Access) because it enables local switching of traffic at the access layer, reducing latency and improving performance for real-time applications. Centralized CAPWAP tunnels would force all traffic back to the WLC, increasing latency. The other options are incorrect because centralized architecture does not inherently provide better RF management, and SD-Access does not require more APs or more WLCs.

Answer

Centralized WLC architecture, because it provides better RF management and security.

Answer

Centralized WLC architecture, because it requires fewer access points to cover the warehouse.

Answer

Converged access (SD-Access) wireless, because it requires fewer WLCs to manage the network.

Question 12

A network engineer is deploying a wireless mesh network using outdoor access points. The mesh APs are configured to use 802.11a/n on the 5 GHz band for backhaul and 802.11b/g/n on the 2.4 GHz band for client access. The engineer notices that the mesh backhaul links are unstable and have high packet loss. What is the most likely cause of the instability?

Accepted Answer

The 5 GHz band is being used for both backhaul and client access, causing co-channel interference.. The correct answer is that the backhaul and client access channels are overlapping, causing interference. Using the same band for both backhaul and client access can lead to co-channel interference, especially if channels are not carefully planned. The other options are less likely: 802.11a/n is not obsolete, mesh backhaul does not require a wired connection, and 5 GHz generally has better range than 2.4 GHz for backhaul.

Answer

The 802.11a/n standard is obsolete and does not support mesh networking.

Answer

The mesh APs require a wired Ethernet connection to the root AP.

Answer

The 2.4 GHz band provides better range for backhaul than the 5 GHz band.

Question 13

Drag and drop the steps of configuring a Layer 2 EtherChannel using PAgP into the correct order, from first to last.

Accepted Answer

Create port-channel interface with interface port-channel command. First, create the port-channel interface globally. Then set the channel-group mode to desirable on the first interface. Next, set the same mode on the second interface. After that, verify the bundle forms using show commands. Finally, assign the port-channel to a VLAN to enable data forwarding. This sequence ensures PAgP negotiation completes before the bundle is used.

Question 14

A network engineer is troubleshooting a wireless network where clients in a conference room experience intermittent connectivity. The engineer notices that the access point in that room is showing a high number of CRC errors on its uplink interface. The AP is connected to a Cisco 9300 switch via a copper cable. What is the most likely cause of the CRC errors?

Accepted Answer

The Ethernet cable is faulty or of poor quality.. CRC errors typically indicate physical layer issues such as faulty cabling, bad connectors, or electromagnetic interference. Since the AP is connected via copper, a faulty cable is the most likely cause. Duplex mismatch would cause alignment errors, not just CRC. AP overload would not cause CRC errors on the uplink. PoE issues would cause power problems, not CRC errors.

Answer

The AP is overloaded with too many clients.

Answer

The switch port is configured with a duplex mismatch.

Answer

The AP is not receiving enough power from Power over Ethernet (PoE).

Question 15

An engineer is configuring a Cisco 9800 WLC for high availability using a pair of WLCs in an active/standby configuration. The engineer configures the same SSID and security settings on both WLCs. However, when the active WLC fails, clients that were connected to the active WLC do not automatically reconnect to the standby WLC. What is the most likely cause?

Accepted Answer

The APs are not configured with the standby WLC's IP address as a backup controller.. The correct answer is that the APs are not configured to use the standby WLC as a backup. In a high availability setup, APs must be configured with both primary and secondary WLC IP addresses. The other options are incorrect: client roaming is not required for failover, SSID names can be the same, and APs do not need to be rebooted after failover if properly configured.

Answer

Clients must be configured to roam between WLCs, which is not supported in active/standby mode.

Answer

The SSID name must be different on the standby WLC to avoid conflicts.

Answer

The APs must be rebooted after the active WLC fails to recognize the standby WLC.