CCNP Practice Test 50 — 15 Questions

Question 1

An engineer is configuring QoS on a Cisco ASR 1000 router to support three traffic classes: voice (EF), video (AF41), and data (default). The link is a 50 Mbps Ethernet circuit. The engineer wants to guarantee 10 Mbps for voice, 20 Mbps for video, and the remaining for data. The current policy uses bandwidth percent statements. During congestion, voice traffic is not receiving its guaranteed bandwidth. What is the most likely cause?

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

Accepted Answer

The interface bandwidth command is not set to 50000 kbps. The bandwidth percent command allocates a percentage of the interface bandwidth, which by default is derived from the physical interface speed. On a Cisco ASR 1000, if the interface bandwidth is not manually set to 50000 kbps, the router may use a different default value (e.g., 1000000 kbps for Ethernet), causing the bandwidth percent to allocate a much larger absolute amount than intended. This leads to incorrect bandwidth guarantees, such as voice not receiving its required 10 Mbps during congestion.

Answer

The voice class should use priority instead of bandwidth

Answer

The video class should use bandwidth remaining percent

Answer

The policy map is applied in the input direction

Question 2

A network engineer is troubleshooting a Layer 2 loop that occurred in a network using Rapid PVST+. The network has three switches: SW1 (root), SW2, and SW3. The engineer examines the topology and finds that SW2 and SW3 are connected via a link that is not supposed to be there. The engineer suspects that an unauthorized switch was connected to the network, causing the loop. The engineer wants to prevent such loops in the future by configuring a feature that will disable any port that receives a BPDU from an unauthorized switch. Which feature should the engineer configure on the access ports?

Accepted Answer

Enable BPDU Guard on all access ports.. BPDU Guard is the correct feature because it immediately error-disables a port when a BPDU is received, preventing loops from unauthorized switches. Since the engineer wants to protect access ports from receiving BPDUs (which should never occur on a properly configured access port), BPDU Guard directly addresses the scenario of an unauthorized switch being connected and sending BPDUs.

Answer

Enable Loop Guard on all access ports.

Answer

Enable Root Guard on all access ports.

Answer

Enable UDLD on all access ports.

Question 3

A network engineer is configuring QoS on a Cisco Catalyst 9300 switch to prioritize voice traffic. The switch has multiple access ports connected to IP phones and PCs. The engineer applies a policy-map that matches DSCP EF and sets the CoS to 5. However, after testing, the voice packets are not being marked correctly. What is the most likely cause?

Accepted Answer

The interface is missing the 'mls qos trust cos' or 'mls qos trust dscp' command.. On Cisco Catalyst switches like the 9300, QoS marking policies applied via a policy-map only re-mark packets if the interface port is configured to trust a specific marking. Without the 'mls qos trust dscp' command, the switch defaults to an untrusted state and may ignore or overwrite the DSCP-to-CoS mapping set by the policy-map. Option C is correct because the missing trust command prevents the policy-map from correctly applying the CoS 5 marking to voice packets.

Answer

The policy-map is not applied to the correct interface direction.

Answer

The switch does not support DSCP-to-CoS mapping.

Answer

The IP phone is not sending packets with DSCP EF.

Question 4

Which three statements about Cisco QoS queuing and scheduling are true? (Choose three.)

Accepted Answer

Strict priority queuing ensures that voice traffic is always sent before other traffic.. Queuing manages packets when output is congested, and scheduling determines the order of transmission. Cisco uses multiple queues (e.g., 4 queues on Catalyst switches) with strict priority or weighted round-robin (WRR). Option A is correct because strict priority queue (PQ) ensures low-latency for voice. Option B is correct because WRR (or shaped round robin) is used for non-priority queues. Option C is correct because the default queue is usually queue 1 (or the best-effort queue). Option D is incorrect because tail drop is a congestion avoidance mechanism applied to a queue, not a scheduling method. Option E is incorrect because scheduling occurs on the egress interface, not ingress.

Answer

Tail drop is a scheduling algorithm that determines which queue to service next.

Answer

Queuing and scheduling are performed on the ingress interface before routing decisions.

Question 5

A network team is designing QoS for a multi-tenant data center using leaf-spine architecture. Each tenant requires guaranteed bandwidth for their mission-critical applications, while best-effort traffic must not interfere. The design must use hierarchical queuing to enforce per-tenant fairness. Which queuing mechanism should the architect implement on the leaf switches?

Accepted Answer

Implement hierarchical QoS (HQoS) with a parent policy shaping per-tenant traffic and a child policy applying class-based weighted fair queuing (CBWFQ) for each tenant's applications.. Hierarchical QoS (HQoS) is the correct choice because it allows the architect to enforce per-tenant bandwidth guarantees using a parent policy (shaping) while applying class-based weighted fair queuing (CBWFQ) in a child policy to prioritize each tenant's mission-critical applications. This two-level structure ensures that best-effort traffic from one tenant cannot starve another tenant's guaranteed traffic, meeting the multi-tenant fairness requirement.

Answer

Use a single level of CBWFQ on all interfaces, classifying traffic by tenant using VLANs.

Answer

Apply strict priority queuing for all mission-critical traffic across all tenants.

Answer

Configure separate physical interfaces for each tenant and apply independent QoS policies.

Question 6

Which three statements about the Differentiated Services (DiffServ) QoS model are true? (Choose three.)

Accepted Answer

DiffServ uses the 6-bit DSCP field in the IP header to mark packets, allowing up to 64 different classes of service.. DiffServ is a class-based model that uses the DSCP field in the IP header to classify traffic. It provides per-hop behavior (PHB) and is scalable because core routers only need to inspect the DSCP field. The model does not guarantee end-to-end bandwidth reservation like IntServ does; instead, it relies on traffic conditioning at the edge.

Answer

In DiffServ, core routers perform complex classification and marking based on deep packet inspection.

Answer

DiffServ requires end-to-end signaling using RSVP to reserve bandwidth along the path.

Question 7

A network engineer runs the following command on Router R1:

R1# show ip bgp summary

BGP router identifier 10.0.0.1, local AS number 65001
BGP table version is 10, main routing table version 10
Neighbor        V           AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
192.168.1.2     4        65002    1024    1020       10    0    0 02:30:15       5
192.168.1.3     4        65003     500     498       10    0    0 00:15:20       3
10.0.0.2        4        65004       0       0        0    0    0 never    Active

Based on this output, what can be concluded?

Accepted Answer

The BGP session to 10.0.0.2 is down due to a TCP connection issue.. The BGP session to neighbor 10.0.0.2 is in the 'Active' state with 'never' uptime and zero messages sent/received. This indicates that the router is actively trying to establish a TCP connection (port 179) but has not yet succeeded, typically due to a connectivity issue such as an unreachable IP, ACL blocking, or incorrect neighbor configuration. The 'Active' state specifically means the BGP process is waiting for the TCP connection to complete, confirming a TCP-level problem.

Answer

All BGP neighbors are fully established.

Answer

The BGP session to 192.168.1.3 has been up for 2 hours 30 minutes.

Answer

The router is receiving prefixes from all neighbors.

Question 8

Drag and drop each traffic shaping or policing characteristic on the left to its correct description on the right.

Accepted Answer

Traffic shaping: Buffers excess traffic to smooth output rate. Traffic shaping buffers excess traffic to smooth output rate. Policing drops or marks excess traffic. Shaping introduces delay; policing does not. Shaping uses a token bucket; policing uses a token bucket. Shaping is applied outbound; policing is typically inbound.

Question 9

Examine the following BGP configuration:

router bgp 65001
 bgp log-neighbor-changes
 neighbor 10.1.1.1 remote-as 65002
 neighbor 10.1.1.1 route-map SET_MED out
!
route-map SET_MED permit 10
 set metric 50

What is the purpose of this configuration?

Accepted Answer

It sets the MED value to 50 for all routes sent to the neighbor 10.1.1.1.. The configuration applies a route-map named SET_MED to outbound updates toward neighbor 10.1.1.1. The route-map permits all routes (no match statement) and sets the Multi-Exit Discriminator (MED) to 50. MED is a BGP path attribute that influences inbound traffic from the neighbor AS, making this path less preferred if the neighbor has a lower MED from another entry point. Thus, all routes sent to 10.1.1.1 will carry a MED of 50.

Answer

It sets the local preference to 50 for routes received from the neighbor.

Answer

It filters routes with a metric of 50 from being advertised to the neighbor.

Answer

It sets the weight to 50 for routes learned from the neighbor.

Question 10

A network engineer runs the following command on Router R1:

R1# show mpls ldp neighbor

Peer LDP Ident: 10.0.0.2:0; Local LDP Ident 10.0.0.1:0
	TCP connection: 10.0.0.2.646 - 10.0.0.1.49231
	State: Oper; Msgs sent/rcvd: 100/95; Downstream
	Up time: 01:23:45
	LDP discovery sources:
	  GigabitEthernet0/0, Src IP addr: 192.168.1.2
        	Addresses bound to peer LDP Ident:
        	  10.0.0.2        192.168.1.2

Based on this output, what can be concluded?

Accepted Answer

The LDP session is using TCP port 646.. The output shows 'TCP connection: 10.0.0.2.646 - 10.0.0.1.49231', which indicates that the LDP session is using TCP port 646 on the peer side. This is the well-known port for Label Distribution Protocol (LDP), as defined in RFC 5036. The session state is 'Oper' (Operational), confirming the session is established and functioning correctly.

Answer

The LDP session is not yet established.

Answer

The LDP neighbor is using a different router ID than 10.0.0.2.

Answer

The LDP session has been up for 1 hour 23 minutes.

Question 11

Drag and drop each STP protection feature on the left to its matching purpose on the right.

Accepted Answer

PortFast: Immediately transitions a port to forwarding state. PortFast moves a port to forwarding immediately; BPDU Guard err-disables a port upon BPDU reception; Root Guard prevents a port from becoming root; Loop Guard prevents alternate/backup ports from transitioning to forwarding.

Question 12

spanning-tree vlan 10 priority 4096

What is the effect of this global configuration command?

Accepted Answer

The switch will have a bridge priority of 4096 for VLAN 10, increasing its chance to become root bridge.. The command `spanning-tree vlan 10 priority 4096` sets the bridge priority for VLAN 10 to 4096. A lower bridge priority value increases the likelihood that this switch will be elected as the root bridge for that VLAN, because the spanning-tree algorithm selects the switch with the lowest bridge priority as the root. However, it does not guarantee immediate root status, as other switches with an even lower priority could still win the election.

Answer

The switch will have a bridge priority of 4096 for all VLANs.

Answer

The switch will become the root bridge for VLAN 10 immediately.

Answer

The switch will have a bridge priority of 4096 for VLAN 10 and all other VLANs will use 32768.

Question 13

Given the following SNMP configuration on a Cisco IOS-XE router:

snmp-server community public RO
snmp-server community private RW
snmp-server location Building-A
snmp-server contact admin@example.com
snmp-server enable traps snmp linkdown linkup
snmp-server host 192.168.1.100 version 2c public

What is the effect of this configuration?

Accepted Answer

The router will send SNMP traps to 192.168.1.100 using community string 'public' for linkdown and linkup events.. The `snmp-server host` command specifies the destination for SNMP notifications, and the community string 'public' is explicitly included in the command, overriding the default behavior of using the first configured RW community. The `snmp-server enable traps snmp linkdown linkup` command enables only linkdown and linkup traps. Therefore, the router sends only those two trap types to 192.168.1.100 using the 'public' community string.

Answer

The router will send SNMP traps to 192.168.1.100 using community string 'private' for all SNMP traps.

Answer

The router will only accept SNMP read requests using community 'public' and write requests using community 'private'.

Answer

The router will send SNMPv3 traps to 192.168.1.100 using authentication.

Question 14

Consider the following EIGRP configuration on a Cisco IOS router:

router eigrp 100
 network 10.0.0.0
 passive-interface default
 no passive-interface GigabitEthernet0/1

What is the effect of this configuration?

Accepted Answer

All interfaces except GigabitEthernet0/1 are passive and will not form EIGRP adjacencies.. The 'passive-interface default' command sets all interfaces to passive by default, preventing them from sending EIGRP hellos and forming adjacencies. The 'no passive-interface GigabitEthernet0/1' command then overrides this default for that specific interface, allowing it to send hellos and form adjacencies. Therefore, only GigabitEthernet0/1 is active for EIGRP neighbor discovery, while all other interfaces remain passive.

Answer

EIGRP hellos are sent on all interfaces, but GigabitEthernet0/1 is prevented from forming adjacencies.

Answer

Only the network 10.0.0.0 is advertised, and all interfaces are passive.

Answer

EIGRP will only form adjacencies on interfaces with an IP address in the 10.0.0.0/8 range.

Question 15

A 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?

Accepted Answer

The EtherChannel is operational with two active links. The output shows that Gi0/1 and Gi0/2 have the flag 'P' (bundled in port-channel), while Gi0/3 has the flag 'D' (down). Therefore, only two links are active in the EtherChannel. The 'SU' flags on Po1 indicate it is a Layer 2 (S) port-channel in use (U), and the protocol is LACP, confirming two active links.

Answer

The EtherChannel is fully operational with three active links

Answer

The EtherChannel is using PAgP protocol

Answer

The EtherChannel is a Layer 3 port-channel