350-601 Network Practice Test 13 — 15 Questions

Question 1

In a Cisco ACI fabric, which component is responsible for managing the policy repository, fault monitoring, and API endpoints?

Accepted Answer

APIC controller. The APIC (Application Policy Infrastructure Controller) is the centralized management and policy engine in Cisco ACI. It maintains the policy repository (the logical and physical policy model), aggregates faults and events from all fabric nodes, and exposes northbound REST API endpoints for automation and integration. Without the APIC, the fabric cannot enforce policies or provide a single point of management.

Answer

DCNM

Answer

Spine switch

Answer

Leaf switch

Question 2

Which VLAN trunking protocol is used by default on Cisco Nexus switches to carry multiple VLANs over a single link?

Accepted Answer

802.1Q. 802.1Q is the IEEE standard trunking protocol used by default on Cisco Nexus switches to carry multiple VLANs over a single link. Unlike older Cisco switches that defaulted to ISL, Nexus switches exclusively support 802.1Q encapsulation for VLAN trunking, as ISL is not supported on the NX-OS platform.

Answer

VTP

Answer

DTP

Answer

ISL

Question 3

Which NX-OS command is used to display the consistency status of Virtual Port Channel (vPC) parameters across both vPC peers?

Accepted Answer

show vpc consistency-parameters. The 'show vpc consistency-parameters' command is specifically designed to verify that all required VPC configuration parameters (such as allowed VLANs, STP settings, and port-channel modes) are identical on both VPC peers. Inconsistent parameters can cause VPC traffic disruption or failover issues, and this command provides a detailed per-interface or global consistency check.

Answer

show vpc peer-keepalive

Answer

show vpc brief

Answer

show running-config vpc

Question 4

A network engineer is configuring OSPF on a Nexus switch. To ensure fast convergence in case of a link failure, which OSPF feature should be enabled?

Accepted Answer

OSPF Fast Hello. OSPF Fast Hello (B) is the correct feature to enable for fast convergence on a Nexus switch because it reduces the dead interval to less than one second by sending Hello packets at sub-second intervals (e.g., every 333 ms for a 1-second dead interval). This allows OSPF neighbors to detect a link failure much faster than the default 40-second dead interval on broadcast networks, triggering quicker SPF recalculation and route convergence.

Answer

OSPF authentication

Answer

OSPF stub area

Answer

OSPF route summarization

Question 5

An engineer is configuring BGP EVPN for VXLAN in a spine-leaf fabric. The leaf switches must advertise host IP-to-MAC mappings to the control plane. Which BGP address family should be enabled on the leaf switches?

Accepted Answer

address-family l2vpn evpn. In a VXLAN BGP EVPN fabric, leaf switches must advertise host IP-to-MAC mappings using the BGP EVPN address family. This is enabled with the command 'address-family l2vpn evpn' under the BGP configuration, which carries Type-2 routes (MAC/IP advertisement routes) that contain both the MAC address and the associated IP address of the host.

Answer

address-family vpnv4 unicast

Answer

address-family ipv4 unicast

Answer

address-family link-state

Question 6

An ACI fabric has multiple tenants and the requirement to allow only HTTP traffic from the web EPG to the app EPG. The contract must restrict traffic to TCP port 80. Which ACI object defines that specific port?

Accepted Answer

Filter. In Cisco ACI, a Filter is the object that defines specific Layer 4 parameters such as TCP port 80. It is referenced by a Subject within a Contract. The Filter contains entries that specify protocols, ports, and other match criteria.

Answer

EPG

Answer

Subject

Answer

Contract

Question 7

What is the purpose of the vPC peer keepalive link in a vPC domain?

Accepted Answer

To provide a keepalive mechanism to detect peer failure. The vPC peer keepalive link is a dedicated Layer 3 link used to detect a failure of the vPC peer switch. It sends periodic UDP-based keepalive messages (default every second) to ensure the peer is still operational, allowing the surviving switch to take over the vPC forwarding role. This mechanism is critical for preventing dual-active scenarios where both switches would incorrectly forward traffic for the same vPC VLAN.

Answer

To synchronize MAC address tables

Answer

To carry BPDUs for STP

Answer

To forward data traffic between vPC peers

Question 8

An engineer is troubleshooting a BGP EVPN issue where leaf switches are not learning remote MAC addresses. The underlay is reachable and BGP sessions are established. What is a likely cause?

Accepted Answer

Missing 'address-family l2vpn evpn' under the BGP neighbor configuration. Even when the underlay is reachable and BGP sessions are established, the BGP EVPN control plane requires the 'address-family l2vpn evpn' to be explicitly activated under the BGP neighbor configuration. Without this, the leaf switch will not exchange EVPN routes (Type-2 MAC/IP advertisement routes) with its peers, so remote MAC addresses are never learned. This is a common misconfiguration because BGP sessions may appear up but are not carrying the necessary EVPN address family.

Answer

NVE interface not enabled

Answer

Incorrect VNI configuration

Answer

MTU mismatch on the underlay

Question 9

Which ECMP load-balancing method is recommended for data center spine-leaf fabrics to ensure optimal traffic distribution?

Accepted Answer

Per-flow load balancing based on src-dst IP. Per-flow load balancing based on src-dst IP ensures that all packets belonging to the same flow (identified by source and destination IP addresses) follow the same path, preventing packet reordering while still distributing different flows across multiple equal-cost paths. In spine-leaf fabrics, this method provides optimal traffic distribution because it leverages the IP header information that is consistently available across Layer 3 boundaries, aligning with the fabric's routing-based forwarding model.

Answer

Per-packet load balancing

Answer

Weighted load balancing

Answer

Per-flow load balancing based on src-dst MAC

Question 10

In a Cisco NX-OS environment, which command is used to verify the operational state of a virtual Port Channel (vPC) peer link?

Accepted Answer

show vpc brief. The 'show vpc brief' command displays the operational state of the vPC peer link, including whether the peer link is up, the role of the switch (primary/secondary), and the status of the vPC domain. This command is specifically designed to verify the health and operational status of the vPC peer link and member ports in a Cisco NX-OS environment.

Answer

show port-channel summary

Answer

show running-config vpc

Answer

show vpc consistency-parameters

Question 11

In a VXLAN overlay network, what is the primary purpose of ingress replication for BUM traffic?

Accepted Answer

To forward broadcast, unknown unicast, and multicast traffic without requiring multicast in the underlay. Ingress replication is a technique used in VXLAN overlay networks to handle BUM (Broadcast, Unknown unicast, Multicast) traffic without requiring a multicast-enabled underlay. The ingress VTEP (VXLAN Tunnel End Point) replicates the BUM packet and sends a separate unicast copy to each remote VTEP in the same VXLAN Network Identifier (VNI) segment, ensuring all relevant endpoints receive the traffic while relying solely on unicast routing in the underlay.

Answer

To reduce the need for ARP suppression

Answer

To enable multipathing of BUM traffic across multiple paths

Answer

To assign VXLAN Network Identifiers (VNIs) to tenant traffic

Question 12

In a Cisco ACI fabric, which object represents a collection of endpoints that share the same forwarding behavior and security policies?

Accepted Answer

Endpoint Group (EPG). In Cisco ACI, an Endpoint Group (EPG) is a logical object that groups endpoints (e.g., servers, VMs) with identical forwarding behavior and security policies. EPGs are the fundamental unit for applying contracts (security policies) and defining communication rules within the fabric, ensuring consistent traffic handling across all members.

Answer

VRF

Answer

Tenant

Answer

Bridge Domain (BD)

Question 13

A network engineer is designing a spine-leaf fabric with oversubscription ratio of 3:1. Each leaf switch uses 40 Gbps uplinks to the spine and has 48 x 10 Gbps server ports. How many spine links are needed per leaf to achieve the target oversubscription?

Accepted Answer

4. The oversubscription ratio is the ratio of server-facing bandwidth to spine-facing bandwidth. Each leaf has 48 x 10 Gbps = 480 Gbps of server-facing capacity. To achieve a 3:1 oversubscription ratio, the spine-facing bandwidth must be 480 Gbps / 3 = 160 Gbps. Since each uplink is 40 Gbps, you need 160 / 40 = 4 spine links per leaf.

Answer

3

Answer

2

Answer

5

Question 14

Which statement about RSTP (802.1w) is true?

Accepted Answer

RSTP reduces convergence time by using a proposal/agreement handshake. RSTP (802.1w) significantly reduces convergence time compared to legacy STP by using a proactive proposal/agreement handshake mechanism. Instead of relying on timers (like STP's 30-50 second convergence), RSTP switches immediately negotiate port roles and transition to forwarding by exchanging proposal and agreement BPDUs, enabling sub-second convergence in a properly designed network.

Answer

RSTP uses a timer-based convergence similar to STP

Answer

RSTP requires explicit configuration of edge ports to prevent loops

Answer

RSTP elects the root bridge based on the highest MAC address

Question 15

In a VXLAN environment, what is the function of a VTEP?

Accepted Answer

It encapsulates and decapsulates VXLAN packets. A VTEP (VXLAN Tunnel Endpoint) is the device that performs VXLAN encapsulation and decapsulation. It takes an original Layer 2 frame, adds a VXLAN header (with a VNI to identify the tenant segment), a UDP header (port 4789), and an outer IP/Ethernet header, then sends the packet over the underlay network. On the receiving side, the VTEP strips these headers and forwards the original frame to the destination host. This encapsulation/decapsulation function is the core purpose of a VTEP in a VXLAN environment.

Answer

It manages the VXLAN multicast groups

Answer

It acts as a DHCP server for tenant VMs

Answer

It provides Layer 3 routing between VXLAN segments