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A network engineer is troubleshooting a connectivity issue between two switches, SW1 and SW2, connected via a trunk link. SW1 is a Cisco Catalyst 3850 running IOS-XE, and SW2 is a Cisco Catalyst 2960 running IOS. The trunk is configured as a dynamic desirable mode on SW1 and dynamic auto on SW2. The engineer notices that the trunk is not forming. What is the most likely cause?
2An engineer is configuring a new access switch for a branch office. The switch must support multiple VLANs for different departments: VLAN 10 (Engineering), VLAN 20 (Sales), and VLAN 30 (Management). The uplink to the distribution switch is a trunk. The engineer wants to ensure that only the required VLANs are allowed on the trunk and that the native VLAN is changed from the default to VLAN 99 for security reasons. Which configuration commands should the engineer apply on the access switch's uplink interface?
3A network engineer is deploying a new server farm with multiple servers connected to a Cisco Nexus 9000 switch. Each server is dual-homed to two separate access switches for redundancy. The servers are configured with NIC teaming in active-standby mode. The engineer wants to ensure that if the active link fails, traffic continues without interruption. The access switches are connected to each other via a trunk. Which technology should the engineer implement on the access switches to prevent loops and allow both uplinks to be active?
4An engineer is troubleshooting a problem where a host in VLAN 20 cannot communicate with a host in VLAN 30, even though both are connected to the same access switch. The access switch is configured with VLANs 20 and 30, and the uplink to the distribution switch is a trunk that allows both VLANs. The distribution switch has SVIs for both VLANs and IP routing is enabled. The engineer verifies that the trunk is up and both VLANs are allowed. What is the most likely cause of the communication failure?
5A network engineer is configuring a new Cisco Catalyst 9300 switch to connect to an existing network. The uplink to the core switch is configured as a trunk. The engineer wants to ensure that all VLANs except VLAN 1 are allowed on the trunk, and that the native VLAN is set to VLAN 999. Which configuration should the engineer apply on the uplink interface?
6An engineer is troubleshooting a connectivity issue between two switches, SW1 and SW2, connected via a trunk. The trunk is configured with switchport mode trunk on both sides. The engineer notices that some VLANs are not passing traffic, even though they are in the allowed list. The output of 'show interfaces trunk' on SW1 shows that VLANs 10, 20, and 30 are in the allowed list and are active. However, hosts in VLAN 30 cannot reach the distribution switch. What is the most likely cause?
7A network engineer is configuring a new Cisco Catalyst switch to connect to an existing network. The uplink to the distribution switch is configured as a trunk. The engineer wants to ensure that the trunk uses 802.1Q encapsulation and that the native VLAN is set to VLAN 100. The distribution switch is a Cisco Catalyst 3850. Which configuration should the engineer apply on the uplink interface?
8An engineer is troubleshooting a problem where a trunk link between two Cisco switches is not passing traffic for VLAN 10, but other VLANs are working. The trunk is configured with switchport mode trunk on both sides. The engineer checks the allowed VLAN list and sees VLAN 10 is included. The native VLAN is set to 1 on both sides. What is the most likely cause?
9A network engineer is configuring a new Cisco Nexus 9000 switch to connect to an existing Cisco Catalyst 3850 switch. The link between them should be a trunk carrying VLANs 10, 20, and 30. The engineer configures the Nexus switch with 'switchport mode trunk' and 'switchport trunk allowed vlan 10,20,30'. However, the trunk does not come up. The Catalyst switch is configured with 'switchport mode trunk' and 'switchport trunk allowed vlan 10,20,30'. What is the most likely cause?
10A network engineer runs the following command on Switch SW1: SW1# show vlan brief VLAN Name Status Ports ---- -------------------------------- --------- ------------------------------- 1 default active Gi0/1, Gi0/2, Gi0/3 10 Sales active Gi0/4, Gi0/5 20 Engineering active Gi0/6, Gi0/7 1002 fddi-default act/unsup 1003 token-ring-default act/unsup 1004 fddinet-default act/unsup 1005 trnet-default act/unsup Based on this output, what can be concluded?
11A network engineer runs the following command on Switch SW1: SW1# show interfaces trunk Port Mode Encapsulation Status Native vlan Gi0/1 on 802.1q trunking 1 Gi0/2 on 802.1q trunking 1 Port Vlans allowed on trunk Gi0/1 1-1005 Gi0/2 1-1005 Port Vlans allowed and active in management domain Gi0/1 1,10,20 Gi0/2 1,10,20 Port Vlans in spanning tree forwarding state and not pruned Gi0/1 1,10,20 Gi0/2 1,10,20 Based on this output, what can be concluded?
12A network engineer runs the following command on Switch SW1: SW1# show interfaces gi0/1 switchport Name: Gi0/1 Switchport: Enabled Administrative Mode: trunk Operational Mode: trunk Administrative Trunking Encapsulation: dot1q Operational Trunking Encapsulation: dot1q Negotiation of Trunking: On Access Mode VLAN: 1 (default) Trunking Native Mode VLAN: 1 (default) Administrative Native VLAN tagging: enabled Voice VLAN: none Administrative private-vlan host-association: none Administrative private-vlan mapping: none Administrative private-vlan trunk native VLAN: none Administrative private-vlan trunk Native VLAN tagging: enabled Administrative private-vlan trunk encapsulation: dot1q Administrative private-vlan trunk normal VLANs: none Administrative private-vlan trunk private VLANs: none Operational private-vlan: none Trunking VLANs Enabled: ALL Pruning VLANs Enabled: 2-1001 Capture Mode Disabled Capture VLANs Allowed: ALL Based on this output, what can be concluded?
13A network engineer runs the following command on Switch SW1: SW1# show spanning-tree vlan 10 VLAN0010 Spanning tree enabled protocol ieee Root ID Priority 32778 Address 0011.2233.4455 This bridge is the root Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Bridge ID Priority 32778 (priority 32768 sys-id-ext 10) Address 0011.2233.4455 Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Aging Time 300 sec Interface Role Sts Cost Prio.Nbr Type ---------------- ---- --- --------- -------- -------------------------------- Gi0/1 Desg FWD 4 128.1 P2p Gi0/2 Desg FWD 4 128.2 P2p Gi0/3 Desg FWD 4 128.3 P2p Based on this output, what can be concluded?
14A network engineer runs the following command on Switch SW1: SW1# show etherchannel summary Flags: D - down P - bundled in port-channel I - stand-alone s - suspended H - Hot-standby (LACP only) R - Layer3 S - Layer2 U - in use N - not in use, no aggregation f - failed to allocate aggregator M - not in use, minimum links not met u - unsuitable for bundling w - waiting to be aggregated d - default port Number of channel-groups in use: 1 Number of aggregators: 1 Group Port-channel Protocol Ports ------+-------------+-----------+-------------------------------------------- 1 Po1(SU) LACP Gi0/1(P) Gi0/2(P) Gi0/3(D) Based on this output, what can be concluded?
15A network engineer runs the following command on Switch SW1: SW1# show vlan id 10 VLAN ID: 10 VLAN Name: Sales VLAN Type: Ethernet VLAN State: active MTU: 1500 Remote SPAN VLAN: No Primary VLAN ID: 10 Private VLAN Type: Primary Associated Secondary VLAN IDs: 100, 200 Based on this output, what can be concluded?
16A network engineer runs the following command on Switch SW1: SW1# show interfaces gi0/1 trunk Port Mode Encapsulation Status Native vlan Gi0/1 desirable n-802.1q trunking 1 Port Vlans allowed on trunk Gi0/1 1-1005 Port Vlans allowed and active in management domain Gi0/1 1,10,20 Port Vlans in spanning tree forwarding state and not pruned Gi0/1 1,10,20 Based on this output, what can be concluded?
17A network engineer runs the following command on Switch SW1: SW1# show dtp interface gi0/1 DTP information on GigabitEthernet0/1: DTP: Enabled DTP mode: Desirable DTP negotiate: TRUE DTP status: Trunk DTP trunk status: Trunking DTP timer: 30 DTP max-age: 2 DTP encapsulation: 802.1q DTP refresh rate: Both DTP requests: 10 DTP errors: 0 Based on this output, what can be concluded?
18A network engineer runs the following command on Switch SW1: SW1# show interfaces gi0/1 trunk Port Mode Encapsulation Status Native vlan Gi0/1 on 802.1q trunking 1 Port Vlans allowed on trunk Gi0/1 10,20 Port Vlans allowed and active in management domain Gi0/1 10,20 Port Vlans in spanning tree forwarding state and not pruned Gi0/1 10,20 Based on this output, what can be concluded?
19Given the following configuration on a Cisco IOS-XE switch: interface GigabitEthernet0/1 switchport mode trunk switchport trunk native vlan 999 switchport trunk allowed vlan 10,20,30 What is the effect of this configuration?
20Examine the following configuration snippet on a Cisco IOS switch: interface GigabitEthernet0/2 switchport mode access switchport access vlan 50 spanning-tree portfast Which statement is true about this interface?
21Consider the following configuration on a Cisco IOS-XE switch: interface GigabitEthernet0/3 switchport trunk encapsulation dot1q switchport mode trunk switchport trunk native vlan 1 What is the effect of this configuration?
22Given the following configuration on a Cisco IOS switch: interface GigabitEthernet0/4 switchport mode trunk switchport trunk allowed vlan except 100-200 What is the effect of this configuration?
23Examine the following configuration on a Cisco IOS-XE switch: interface GigabitEthernet0/5 switchport mode trunk switchport trunk native vlan 999 switchport trunk allowed vlan 10,20,30 switchport nonegotiate What is the effect of the 'switchport nonegotiate' command?
24Given the following configuration on a Cisco IOS switch: interface GigabitEthernet0/6 switchport mode dynamic desirable What is the effect of this configuration?
25What is the default native VLAN on a Cisco switch trunk port?
26Which of the following is a valid VLAN range that can be created on a Cisco IOS switch?
27What is the purpose of the Dynamic Trunking Protocol (DTP) on Cisco switches?
28Drag and drop the steps of Dynamic Trunking Protocol (DTP) negotiation into the correct order, from first to last.
29Drag and drop the steps of configuring a native VLAN mismatch detection into the correct order, from first to last.
30Drag and drop the steps of adding a new VLAN to a trunk link into the correct order, from first to last.
31Drag and drop the steps of VLAN pruning on trunks using VTP into the correct order, from first to last.
32Drag and drop the steps of Private VLAN (PVLAN) configuration steps into the correct order, from first to last.
33Drag and drop the steps of Q-in-Q (802.1ad) double-tagging configuration into the correct order, from first to last.
34Drag and drop the steps of VLAN mapping on trunk interfaces into the correct order, from first to last.
35Drag and drop the steps of SVI configuration for inter-VLAN routing into the correct order, from first to last.
36Drag and drop the steps of VLAN pruning on trunks using VTP into the correct order, from first to last.
37Drag and drop the steps of Private VLAN (PVLAN) configuration steps into the correct order, from first to last.
38Drag and drop the steps of Q-in-Q (802.1ad) double-tagging configuration into the correct order, from first to last.
39Drag and drop the steps of VLAN mapping on trunk interfaces into the correct order, from first to last.
40Drag and drop the steps of SVI configuration for inter-VLAN routing into the correct order, from first to last.
41Drag and drop each VLAN range on the left to its matching type on the right.
42Drag and drop each DTP mode on the left to its matching trunking behavior on the right.
43Drag and drop each trunk encapsulation on the left to its matching standard on the right.
44Drag and drop each VTP mode on the left to its matching capability on the right.
45Drag and drop each VLAN type on the left to its matching purpose on the right.
46Drag and drop each VLAN range on the left to its matching type on the right.
47Drag and drop each DTP mode on the left to its matching trunking behavior on the right.
48Drag and drop each trunk encapsulation type on the left to its matching standard or characteristic on the right.
49Drag and drop each VTP mode on the left to its matching capability on the right.
50Drag and drop each VLAN type on the left to its matching purpose on the right.
51Which two statements about VLAN trunking using IEEE 802.1Q are true? (Choose two.)
52Which three statements about Dynamic Trunking Protocol (DTP) are true? (Choose three.)
53Which two statements about VLAN configuration and verification on a Cisco IOS switch are true? (Choose two.)
54Which two statements about DTP (Dynamic Trunking Protocol) are true? (Choose two.)
55Which three statements about trunking and VLAN pruning are true? (Choose three.)
56Which two statements about native VLANs on an 802.1Q trunk are true? (Choose two.)
57Which three statements about VLAN configuration and verification are true? (Choose three.)
58Which three statements about trunking and VLAN pruning are true? (Choose three.)
The VLANs and Trunking domain covers the key concepts tested in this area of the 350-401 exam blueprint published by Cisco. Courseiva provides free domain-focused practice, mock exams, missed-question review, and readiness tracking across all 350-401 domains — no account required.
The Courseiva 350-401 question bank contains 58 questions in the VLANs and Trunking domain. Click any question to see the full explanation and answer breakdown.
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