350-601 Network Practice Test 3 — 15 Questions

Question 1

Which command displays the VLANs allowed on a trunk interface?

Accepted Answer

show interface trunk. The 'show interface trunk' command displays trunk parameters, including the VLANs allowed on the trunk interface. This command shows the trunking mode, encapsulation (e.g., 802.1Q), and the allowed VLAN list for each trunk port. It is the direct command to verify which VLANs are permitted on a specific trunk link.

Answer

show running-config interface

Answer

show vlan

Answer

show interface switchport

Question 2

In a VXLAN EVPN multi-tier design, which feature ensures traffic between leaf switches takes the optimal path without hair-pinning through a spine?

Accepted Answer

ECMP. C is correct because Equal-Cost Multipath (ECMP) in a VXLAN EVPN multi-tier design allows leaf switches to load-balance traffic across multiple equal-cost spine paths, ensuring that traffic between leaf switches takes the most direct route without being forced to hair-pin through a spine. ECMP leverages the underlying IP fabric's routing to forward VXLAN-encapsulated packets over any available spine, avoiding suboptimal forwarding that would occur if a single spine were used as a relay.

Answer

Anycast gateway

Answer

Type-2 routes

Answer

ARP suppression

Question 3

A network engineer is verifying VPC configuration on a pair of Nexus switches. Which two commands should be used to check VPC status and consistency? (Choose two.)

Accepted Answer

show vpc consistency-parameters. (show vpc) is correct because it displays the overall VPC status, including the local and peer VPC system MAC, role, and the operational state of each VPC member port. Option B (show vpc consistency-parameters) is correct because it verifies that critical parameters (e.g., STP mode, VLAN interfaces, MTU) are consistent between the two VPC peers, which is essential for VPC to function correctly and avoid traffic black-holing.

Answer

show vpc role

Answer

show vpc peer-keepalive

Answer

show vpc statistics

Question 4

Which three EVPN route types are essential for VXLAN EVPN operation in a typical data center fabric? (Choose three.)

Accepted Answer

Type-3 (Inclusive Multicast Ethernet Tag). Type-3 (Inclusive Multicast Ethernet Tag) routes are essential for VXLAN EVPN because they enable BUM traffic replication across the underlay network by advertising the VNI and multicast group mapping, allowing VTEPs to join the correct multicast tree for flooding unknown unicast, broadcast, and multicast frames.

Answer

Type-4 (Ethernet Segment)

Answer

Type-1 (Ethernet Auto-Discovery)

Question 5

When configuring BGP EVPN on spine switches functioning as route reflectors, which two address families must be configured? (Choose two.)

Accepted Answer

address-family l2vpn evpn. B is correct because BGP EVPN (Ethernet VPN) uses the L2VPN address family (l2vpn evpn) to carry MAC/VXLAN routing information between spine and leaf switches. This address family is mandatory for EVPN control plane operation in a VXLAN fabric, enabling MAC address learning and advertisement via MP-BGP.

Answer

address-family link-state

Answer

address-family ipv6 unicast

Answer

address-family vpnv4

Question 6

Refer to the exhibit. What is the current state of the VPC domain?

Accepted Answer

Operational. The exhibit shows the output of 'show vpc' with the vPC domain ID set to 100, the peer-keepalive link status as 'Active', and the peer-link status as 'up'. The vPC role is 'primary' and the operational status is listed as 'operational', which indicates that the vPC domain is fully functional and all consistency checks have passed. Therefore, the current state is operational.

Answer

VPC domain not configured

Answer

Peer-link down

Answer

Consistency check failed

Question 7

Refer to the exhibit. Which VLANs are allowed on the VPC peer-link?

Accepted Answer

VLANs 1-100 only. In a vPC domain, the peer-link carries only specific VLANs that are allowed on the trunk. By default, the peer-link is configured as a trunk allowing VLANs 1-100, and the native VLAN is not included in this allowed list because the peer-link uses a dedicated VLAN for control traffic (typically VLAN 4094) and does not forward native VLAN traffic. Option C is correct because the default allowed VLAN list on a vPC peer-link is VLANs 1-100, as shown in the exhibit.

Answer

VLANs 1-100 and native VLAN

Answer

Only VLAN 1

Answer

All VLANs (1-4094)

Question 8

Refer to the exhibit. What is the most likely cause of the NVE interface being down?

Accepted Answer

The source interface is not configured.. The NVE (Network Virtualization Edge) interface requires a valid source interface (typically a loopback) to establish VXLAN tunnels. If the source interface is not configured under the NVE interface, the interface remains in a down state because it cannot form VXLAN overlay adjacencies. This is the most common cause of an NVE interface being down in Cisco NX-OS.

Answer

The VXLAN destination UDP port is incorrect.

Answer

The overlay VLAN is not configured.

Answer

The VNI list is empty.

Question 9

A network engineer is troubleshooting VXLAN connectivity between two VTEPs. The source VTEP is configured with `nve1` and member VNI 10000. The `show nve peers` command shows the remote VTEP IP but the status is 'Init'. What is a likely cause?

Accepted Answer

The multicast group is not reachable.. The 'Init' status in the output of 'show nve peers' indicates that the VXLAN tunnel endpoint (VTEP) has learned the remote VTEP IP address (likely via BGP EVPN or static configuration) but is unable to complete the tunnel establishment. In VXLAN multicast mode, the underlay multicast group is used for BUM traffic and for VTEP discovery. If the multicast group is not reachable (e.g., due to missing PIM configuration, incorrect RP, or firewall filtering), the source VTEP cannot receive the multicast join or data from the remote VTEP, leaving the peer stuck in 'Init' state.

Answer

The remote VTEP is not configured with the same VNI.

Answer

The MTU is too low.

Answer

The VRF is mismatched between the VTEPs.

Question 10

An engineer is designing a Layer 3 network for a data center using OSPF. The core switches are connected to aggregation switches. To optimize convergence, which OSPF network type should be used on the links between core and aggregation?

Accepted Answer

point-to-point. In a data center spine-leaf architecture, the links between core (spine) and aggregation (leaf) switches are typically point-to-point Layer 3 links. Configuring OSPF network type point-to-point (option D) on these interfaces eliminates the need for DR/BDR election, reduces hello and dead timers (default 10s/40s vs 30s/120s for broadcast), and allows faster convergence because OSPF immediately forms a neighbor adjacency without waiting for election delays.

Answer

broadcast

Answer

non-broadcast

Answer

point-to-multipoint

Question 11

In an EVPN-VXLAN fabric, a network engineer notices that MAC addresses learned from an external router are not being advertised as EVPN type-2 routes. The external router is connected to a leaf switch via a Layer 3 port. Which additional configuration is needed on the leaf switch?

Accepted Answer

Configure `ip arp evpn` on the Layer 3 interface.. When an external router is connected via a Layer 3 port, the leaf switch learns the router's MAC address through ARP, not through a VLAN. To advertise this MAC as an EVPN type-2 route, the `ip arp evpn` command must be configured on the Layer 3 interface. This command enables the switch to synchronize ARP entries into the EVPN BGP control plane, allowing MAC/IP advertisement for directly connected hosts on routed interfaces.

Answer

Configure `redistribute host-routes` under the BGP address-family l2vpn evpn.

Answer

Configure `evpn` under the VLAN interface associated with the external router's VLAN.

Answer

Configure `routing-config` under BGP to enable both MAC-VRF and IP-VRF.

Question 12

A data center switch has multiple access ports configured with spanning-tree portfast. A new server is connected to one of these ports and immediately causes a network loop. What is the most likely cause?

Accepted Answer

The port is not configured with BPDUguard.. Spanning Tree Protocol (STP) PortFast immediately transitions a port to the forwarding state, bypassing the listening and learning phases. However, PortFast alone does not protect against loops if a rogue device (like a server) inadvertently connects two switch ports or sends BPDUs. BPDUguard must be explicitly configured on the port to disable it upon receiving any BPDU, preventing a loop. Without BPDUguard, the switch will process the BPDU and may re-enter STP convergence, potentially causing a loop if the server is misconfigured or bridging traffic.

Answer

The portfast feature is disabled by default on the switch.

Answer

The server sends BPDUs.

Answer

The switch is running MSTP instead of PVST+.

Question 13

A network engineer is configuring a Fabric Extender (FEX) to connect to a parent switch. Which best practice should be followed for FEX host interfaces?

Accepted Answer

Enable Virtual Port Channel (vPC) on the parent switch.. Enabling Virtual Port Channel (vPC) on the parent switch is a best practice for FEX host interfaces because it allows the FEX to be dual-homed to two separate parent switches, providing link-level redundancy and active-active forwarding. Without vPC, the FEX would rely on a single parent switch, creating a single point of failure and potentially causing traffic black-holing during a parent switch failure.

Answer

Configure all host interfaces as trunk ports.

Answer

Use the same FEX ID for redundancy.

Answer

Use LACP for the FEX uplinks.

Answer

Disable spanning-tree on FEX host interfaces.

Question 14

In a vPC domain, a consistency check failure is observed for the vPC keepalive link. What is the impact on the vPC domain operation?

Accepted Answer

The vPC domain will continue to operate but with reduced reliability.. The vPC keepalive link is used as a secondary heartbeat to detect dual-active scenarios when the peer link fails. A consistency check failure on the keepalive link does not directly affect data forwarding; the vPC domain continues to operate, but the loss of this redundancy mechanism reduces reliability because the switches can no longer reliably detect a split-brain condition without the peer link.

Answer

The vPC peer link will be suspended.

Answer

The secondary switch will shutdown its vPC member ports.

Answer

Both switches will independently forward traffic via the vPC peer link.

Question 15

A multicast application requires that all receivers join the same group using PIM sparse mode. Which router is responsible for forwarding traffic from the source to the RP?

Accepted Answer

First-hop router. In PIM sparse mode, the first-hop router (the router directly connected to the multicast source) is responsible for encapsulating the source's multicast traffic in unicast PIM register messages and forwarding them to the rendezvous point (RP). This process establishes the initial path and triggers the RP to join the source-specific tree (SPT) toward the source.

Answer

Rendezvous point (RP)

Answer

Last-hop router

Answer

Source-specific router