350-401 Mock Exam 72 — 25 Questions

Question 1

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?

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

Accepted Answer

The Ethernet cable is faulty or of poor quality.. CRC errors on an Ethernet interface indicate that frames are being received with invalid checksums, typically due to physical-layer issues such as signal degradation, crosstalk, or faulty cabling. Since the AP is connected via a copper cable to a Cisco 9300 switch, a faulty or poor-quality Ethernet cable is the most direct cause of these errors, as it can introduce bit errors that corrupt the frame's FCS.

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 2

A network engineer executes the following command on Router R8:

R8# show ip sla monitor summary

IP SLAs Monitor Summary
Codes: * active, ^ inactive, ~ pending

ID       Type         Destination       Stats       Return Code      Last
*1       icmp-echo    192.168.8.10      Success     OK               1
^2       udp-jitter   192.168.8.20      Success     OK               2
*3       icmp-echo    192.168.8.30      Success     OK               3

Based on this output, which IP SLA operations are currently active?

Accepted Answer

IDs 1 and 3. The output shows that IP SLA operations with IDs 1 and 3 are marked with an asterisk (*), which according to the legend indicates 'active' status. Operation ID 2 is marked with a caret (^), meaning it is 'inactive'. Therefore, only IDs 1 and 3 are currently active.

Answer

Only ID 1

Answer

Only ID 2

Answer

All three operations

Question 3

Which two statements about Cisco QoS classification and marking are true? (Choose two.)

Accepted Answer

A class map can match traffic based on DSCP, CoS, IP precedence, or ACL.. Option A is correct because a Cisco class map (defined with the class-map command and used inside a policy map) can match traffic using criteria such as DSCP values, CoS bits, IP precedence, or ACLs (match dscp, match cos, match precedence, match access-group), which is exactly how classification is performed in MQC. Option B is correct because QoS marking is best done as close to the traffic source as possible, typically at the access layer, so that the DSCP/CoS value is preserved and honored by every downstream device without reclassification. Option C is incorrect because marking is not limited to Layer 2 CoS; devices can also set Layer 3 DSCP and IP precedence (and MPLS EXP), so CoS-only marking is false. Option D is incorrect because tail drop is a congestion avoidance/queue management mechanism, not a marking function, and marking itself is not a congestion avoidance mechanism. Option E is incorrect because a policy map (not a class map) applies marking actions to classified traffic; the class map only identifies/matches the traffic.

Answer

Marking can only be applied to Layer 2 frames using CoS bits.

Answer

Marking is a congestion avoidance mechanism that uses tail drop.

Answer

A class map is used to apply marking actions to classified traffic.

Question 4

Drag and drop each hypervisor product on the left to its matching vendor on the right.

Accepted Answer

vSphere: VMware. VMware vSphere is from VMware, KVM is from Red Hat (open source, but Red Hat is the primary commercial backer), Microsoft Hyper-V is from Microsoft, Xen is from Citrix (originally from the Xen Project), and Oracle VM is from Oracle.

Question 5

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 2.4 GHz band provides better range for backhaul than the 5 GHz band.. The instability is most likely due to the use of the 5 GHz band for backhaul. While 5 GHz offers higher throughput, it has significantly shorter range and greater attenuation than 2.4 GHz. In an outdoor mesh network, APs may be spaced far apart, and obstacles can cause packet loss on the 5 GHz link. The 2.4 GHz band would provide better range and stability for backhaul, making option D the correct answer.

Answer

The 5 GHz band is being used for both backhaul and client access, causing co-channel interference.

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.

Question 6

An engineer is deploying a virtual router (vRouter) on a Cisco NFVIS host. The vRouter needs to advertise routes to a physical router connected to the host's management port. The engineer configures the vRouter with an IP address on the same subnet as the management port. However, the physical router does not receive any routing updates. What should the engineer do to enable route exchange?

Accepted Answer

Connect the vRouter to a data plane interface (e.g., a bridge connected to a physical data port) instead of the management port.. In Cisco NFVIS, the management port is isolated from the data plane and is intended only for out-of-band management traffic. Routing protocols like OSPF or BGP cannot exchange routes over the management interface because it lacks the necessary data-plane forwarding capabilities. To advertise routes to a physical router, the vRouter must be connected to a data plane interface, such as a bridge mapped to a physical data port, which supports routing protocol adjacency and packet forwarding.

Answer

Configure a static route on the vRouter pointing to the physical router.

Answer

Enable OSPF on the vRouter's management interface.

Answer

Change the management port to a trunk port to carry routing updates.

Question 7

A network engineer runs the following command on Router R1:

R1# show vrf brief

Name                             Default RD            Protocols   Interfaces
  CUSTOMER_A                       65000:100              ipv4        Gi0/0.100
  CUSTOMER_B                       65000:200              ipv4        Gi0/0.200
  MANAGEMENT                       65000:999              ipv4        Gi0/1

Based on this output, what can be concluded?

Accepted Answer

CUSTOMER_A and CUSTOMER_B are on the same physical interface but different subinterfaces.. The output shows that both CUSTOMER_A and CUSTOMER_B are associated with subinterfaces Gi0/0.100 and Gi0/0.200, which are subinterfaces of the same physical interface Gi0/0. This is a common design for MPLS L3VPN or VRF-lite deployments where multiple VRFs share a single physical link using 802.1Q VLAN tagging.

Answer

All VRFs are using the same route distinguisher.

Answer

The MANAGEMENT VRF is used for customer traffic.

Answer

The router is running MPLS L3VPN.

Question 8

Drag and drop each BGP attribute on the left to its matching type on the right.

Accepted Answer

AS_PATH: Well-known mandatory. AS_PATH and NEXT_HOP are well-known mandatory; LOCAL_PREF is well-known discretionary; MED is optional non-transitive; COMMUNITY is optional transitive.

Question 9

Drag and drop each EIGRP timer on the left to its matching default value on the right.

Accepted Answer

Hello Timer: 5 seconds. Hello timer default is 5 seconds on LAN; Hold timer default is 15 seconds; Active timer default is 3 minutes.

Question 10

Drag and drop the steps of SD-Access fabric border node configuration steps into the correct order, from first to last.

Accepted Answer

Enable LISP on border node. Configuration starts with enabling LISP on the border node, then configuring the EID-to-RLOC mapping and border services. Next, the border is connected to external networks (e.g., WAN), followed by applying VRF and SGT policies, and finally verifying the border operation.

Question 11

Drag and drop each IP SLA reaction action on the left to its corresponding behavior on the right.

Accepted Answer

syslog: Send a log message. Syslog sends a log message; SNMP trap sends an SNMP notification; trigger starts another IP SLA operation; none disables reaction; timeout triggers on probe timeout.

Question 12

Which BGP attribute is preferred when it has the lowest value?

Accepted Answer

MED (Multi-Exit Discriminator). The Multi-Exit Discriminator (MED) is a BGP path attribute used to influence inbound traffic to an AS from multiple entry points. A lower MED value is preferred over a higher one, making it the correct answer among the options where the lowest value is preferred.

Answer

Local Preference

Answer

Weight

Answer

AS Path

Question 13

An Ansible playbook uses the uri module to make a REST API call to Cisco DNA Center:

---
- hosts: localhost
  gather_facts: no
  tasks:
    - name: Get devices
      uri:
        url: "https://dna-center/api/v1/network-device"
        method: GET
        headers:
          X-Auth-Token: "{{ token }}"
        return_content: yes
      register: result

- debug:
        var: result.json

What is missing from this playbook?

Accepted Answer

The playbook is missing a task to authenticate and obtain the X-Auth-Token before making the API call.. The playbook attempts to call the Cisco DNA Center API using the `uri` module with a placeholder `{{ token }}` for the X-Auth-Token header, but it never performs the initial authentication step to obtain that token. Cisco DNA Center requires a POST request to `/api/system/v1/auth/token` with valid credentials (username/password) to receive a token, which must then be used in subsequent API calls. Without this authentication task, the playbook will fail because the token variable is undefined or invalid.

Answer

The playbook will work if the token is defined in the inventory file.

Answer

The playbook should use the 'cisco.dnac' collection instead of the uri module.

Answer

The playbook is missing the 'validate_certs: no' parameter to ignore SSL errors.

Question 14

Given the following configuration:

interface Port-channel1
 no switchport
 ip address 192.168.1.1 255.255.255.0
!
interface GigabitEthernet0/1
 no switchport
 channel-group 1 mode on
!
interface GigabitEthernet0/2
 no switchport
 channel-group 1 mode on

Which statement is true about this EtherChannel?

Accepted Answer

The EtherChannel will form and operate as a Layer 3 routed interface.. The configuration uses `channel-group 1 mode on`, which forces the EtherChannel to form without any negotiation protocol (LACP or PAgP). Since both interfaces are configured with `no switchport` and an IP address is assigned to the Port-channel interface, the EtherChannel operates as a Layer 3 routed interface. Option B is correct because the channel will form and function as a routed port.

Answer

The EtherChannel will form only if the neighbor also uses LACP active mode.

Answer

The EtherChannel will not form because the interfaces are in no switchport mode.

Answer

The EtherChannel will form but will use PAgP negotiation.

Question 15

Drag and drop the steps of EtherChannel troubleshooting and verification steps into the correct order, from first to last.

Accepted Answer

Check physical port status with 'show interfaces'. Troubleshooting EtherChannel should begin with checking the physical port status using 'show interfaces' to identify any link-level issues such as errors or down ports. Next, verify the EtherChannel bundle with 'show etherchannel summary' to confirm that the bundle is formed and which ports are members. Then, inspect protocol details with 'show etherchannel detail' to look for mismatches in configuration like PAgP/LACP modes or VLAN allowed lists. After that, check load-balancing with 'show etherchannel load-balance' to ensure traffic is distributed as expected. Finally, test end-to-end connectivity with ping and traceroute to confirm data flow across the bundle.

Question 16

A network engineer issues the following command on Router R6:

R6# show ip sla statistics 5

Round Trip Time (RTT) for Index 5
Latest RTT: 150 ms
Latest Operation Start Time: 16:00:00.000 UTC Mon Mar 1 2021
Latest Operation Return Code: OK
Number of successes: 10
Number of failures: 0
Over thresholds: 8

Based on this output, what does the 'Over thresholds: 8' indicate?

Accepted Answer

8 probes had RTT exceeding the configured threshold.. The 'Over thresholds: 8' field indicates that out of the 10 successful probes, 8 of them had a round-trip time (RTT) that exceeded the configured threshold value. This is a key performance metric in IP SLA that helps identify when network latency is degrading beyond acceptable limits, even though the probes themselves completed successfully (return code OK).

Answer

8 probes failed to reach the target.

Answer

8 probes were sent in total.

Answer

The threshold is set to 150 ms.

Question 17

Which three statements about EIGRP packet types are true? (Choose three.)

Accepted Answer

Hello packets are sent unreliably and do not require an acknowledgment.. Option A is correct because EIGRP Hello packets are sent to the multicast address 224.0.0.10 using an unreliable delivery method and are not acknowledged, serving only for neighbor discovery and keepalive. Option C is correct because Query packets are sent reliably, meaning they require an acknowledgment, and each neighbor must respond with a Reply packet to indicate it has processed the query. Option D is correct because ACK packets are unicast to the sender of a reliable EIGRP packet and contain no data, existing solely to acknowledge receipt of reliable packets such as Updates, Queries, and Replies. Option B is incorrect because Update packets are not always multicast; they can be sent as unicast when replying to a specific neighbor or during initial neighbor formation. Option E is incorrect because Reply packets are sent reliably and require acknowledgment, not unreliably, to ensure the querying router receives the response.

Answer

Update packets are always sent as multicast to all EIGRP neighbors.

Answer

Reply packets are sent unreliably to conserve bandwidth.

Question 18

Drag and drop the steps of DNA Center network discovery and device sync into the correct order, from first to last.

Accepted Answer

Define discovery range and credentials. Discovery starts with defining the discovery scope, running the discovery, adding discovered devices to inventory, syncing device details, and finally assigning devices to a site.

Question 19

A company is implementing QoS on its campus network. The network engineer configures a policy-map that sets the CoS value for voice traffic to 5 on a switch interface. However, when the traffic reaches the router, the CoS marking is lost. What is the most likely reason?

Accepted Answer

CoS is a Layer 2 marking and is not carried across a Layer 3 hop; the router must map CoS to DSCP.. CoS (Class of Service) is a Layer 2 marking field in the 802.1Q VLAN tag, which is stripped when a frame passes through a Layer 3 device (router). Since the router operates at Layer 3, it does not preserve the CoS value; instead, the router must map the CoS to a DSCP (Differentiated Services Code Point) value at Layer 3 to maintain QoS across the routed hop. Option B correctly identifies this fundamental Layer 2 vs. Layer 3 boundary issue.

Answer

The router does not trust the CoS marking and re-marks it to 0.

Answer

The switch must be configured to set DSCP instead of CoS.

Answer

The router must have 'mls qos trust cos' configured on the interface.

Question 20

Drag and drop the steps of IP SLA tracking with static route failover into the correct order, from first to last.

Accepted Answer

Define IP SLA operation for reachability. First, the IP SLA operation is defined to monitor reachability. Then a track object is created that references the IP SLA operation. The track object is configured with a threshold for up/down state. A static route is configured with the track object for failover. Finally, the static route is verified to use the track.