350-601 Network Practice Test 2 — 15 Questions

Question 1

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?

Choose an answer to begin — your selection is scored in the full session.

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 2

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 3

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 4

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 5

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

Question 6

An engineer is configuring VXLAN bridging and routing on a Cisco Nexus 9000 switch. Which configuration is required to enable inter-VNI routing?

Accepted Answer

Configure anycast gateway MAC.. Inter-VNI routing requires a shared anycast gateway MAC address across all VTEPs in the same VXLAN fabric. This allows the switch to respond to ARP requests for the gateway IP and forward traffic between different VNIs without relying on a traditional routed interface. The anycast gateway MAC is configured under the VLAN interface (SVI) using the 'fabric forwarding anycast-gateway-mac' command.

Answer

Configure a VLAN interface under the bridge domain.

Answer

Enable ip routing under VRF.

Answer

Configure a VRF and associate the VLAN interface to it.

Question 7

In a BGP EVPN deployment, route type 2 (MAC/IP advertisement) is used to advertise MAC addresses. What additional information is carried in route type 2 for IP routing?

Accepted Answer

IP address and MAC address. In BGP EVPN, route type 2 (MAC/IP Advertisement Route) is used to advertise both MAC addresses and their associated IP addresses. The additional information carried for IP routing is the IP address and the MAC address, enabling the control plane to support both Layer 2 bridging and Layer 3 routing (e.g., host route advertisement for IP-based forwarding). This is defined in RFC 7432, where the route type 2 NLRI includes a MAC address field and an optional IP address field.

Answer

IP address and route distinguisher

Answer

IP prefix and next-hop

Answer

MAC address and VNI

Question 8

An OSPF router in a broadcast network has not formed a neighbor relationship. What are three possible causes? (Choose three.)

Accepted Answer

MTU mismatch. In OSPF, an MTU mismatch prevents the formation of a neighbor relationship because OSPF routers compare the MTU value in Database Description (DBD) packets. If the receiving router's interface MTU is smaller than the DBD packet size, the packet is dropped, and the neighbor state remains stuck in EXSTART/EXCHANGE. This is a common issue on broadcast networks where different link types or misconfigured interfaces exist.

Answer

Authentication incorrect

Answer

Area ID mismatch

Question 9

Which two benefits does EVPN provide compared to traditional VPLS? (Choose two.)

Accepted Answer

Load balancing of traffic across multiple active paths. EVPN uses BGP to advertise MAC addresses and IP prefixes, enabling per-flow load balancing across multiple equal-cost paths via its all-active multi-homing capability. In contrast, traditional VPLS relies on a single active forwarder per site (using Spanning Tree Protocol or VPLS Multihoming), which prevents active-active load balancing and wastes bandwidth.

Answer

Simpler BGP configuration

Answer

Reduced MAC address learning

Answer

No need for MPLS

Question 10

Refer to the exhibit. A network engineer has configured a port-channel for OSPF adjacency. What additional configuration is required for the port-channel to operate correctly?

Accepted Answer

Configure the channel-group mode on member interfaces.. For a port-channel to form an OSPF adjacency, the member interfaces must be configured with a channel-group mode (e.g., 'channel-group 1 mode active') to bundle them into a logical port-channel interface. Without this, the interfaces remain individual Layer 2 or Layer 3 links, and OSPF cannot establish adjacency over the port-channel as a single logical link.

Answer

Set the OSPF priority.

Answer

No additional configuration needed.

Answer

Enable OSPF on the port-channel with `ip router ospf process`.

Question 11

A network engineer is troubleshooting high CPU utilization on a Nexus 9000 switch. Which command is most useful to identify the process consuming the most CPU?

Accepted Answer

show process cpu sort. The 'show process cpu sort' command on Nexus 9000 switches displays the current CPU utilization sorted by the process consuming the most CPU, allowing the engineer to quickly identify the top CPU consumer. This command provides a real-time, sorted list of processes with their CPU usage percentages, which is directly useful for troubleshooting high CPU utilization.

Answer

show processes cpu history

Answer

show system resources

Answer

show cpu usage

Question 12

Which protocol is used by Cisco ACI fabric to distribute endpoint information among spines?

Accepted Answer

COOP. D is correct because the Cisco ACI fabric uses the Council of Oracle Protocol (COOP) specifically to distribute endpoint information (such as IP-to-MAC bindings and location) among spine switches. COOP operates as a lightweight, publish-subscribe protocol that runs between leaf and spine switches, ensuring that all spines maintain a consistent endpoint database without the overhead of a full routing protocol.

Answer

IS-IS

Answer

OSPF

Answer

BGP

Question 13

A Nexus 9000 switch is configured with VPC. The VPC keepalive link fails. What is the effect on the VPC domain?

Accepted Answer

The secondary switch suspends its VPC member ports.. In a VPC domain, the keepalive link is used to monitor the liveness of the peer switch, but it does not carry data traffic. When the keepalive link fails, the secondary switch cannot confirm the primary is alive, so it suspends its VPC member ports to prevent a dual-active scenario. The primary switch remains active and continues forwarding traffic normally because it assumes the secondary has failed.

Answer

Both switches suspend the VPC VLANs.

Answer

Both switches continue to forward traffic normally.

Answer

The primary switch becomes orphan.

Question 14

In a Cisco ACI fabric, a tenant has multiple bridge domains in the same VRF all with 'Unicast Routing' enabled and hardware proxy mode. However, endpoints in different BDs within the same VRF cannot communicate even with a contract. What is a possible reason?

Accepted Answer

The 'ARP Flooding' is enabled.. When 'Unicast Routing' is enabled on a bridge domain (BD) in hardware proxy mode, the ACI fabric relies on hardware proxy for forwarding. In this mode, ARP flooding should be disabled to prevent excessive flooding and allow the fabric to properly resolve ARP via the COOP database. If 'ARP Flooding' is enabled, the fabric floods ARP requests across all BDs, which can cause ARP resolution to fail for endpoints in different BDs because the hardware proxy expects ARP to be handled differently. This prevents inter-BD communication even with a contract in place. Therefore, having 'ARP Flooding' enabled is a possible reason for the communication failure.

Answer

The 'L3 Unknown Multicast Flooding' is set to flood.

Answer

The contracts are unidirectional.

Answer

The bridge domains are in different subnets.

Question 15

Refer to the exhibit. A network engineer notices that the NVE1 interface is up but VXLAN traffic is not being encapsulated. What is the most likely cause?

Accepted Answer

The BGP EVPN address-family is not activated.. VXLAN traffic encapsulation on the NVE1 interface requires the BGP EVPN address-family to be activated under the BGP configuration to exchange VNI-to-VTEP mappings. Without this address-family, the NVE interface cannot learn remote VTEPs, so VXLAN packets are never encapsulated with the outer UDP/IP header.

Answer

The VNI 10000 is not mapped to a VLAN.

Answer

The ingress replication protocol must be static.

Answer

The loopback0 interface is not configured.