300-410 Practice Test 24 — 15 Questions

Question 1

What is the default timeout value (in milliseconds) for an IP SLA operation?

Accepted Answer

5000 ms. The default timeout for an IP SLA operation is 5000 milliseconds (5 seconds). If a response is not received within this time, the probe is considered failed.

Answer

1000 ms

Answer

10000 ms

Answer

60000 ms

Question 2

Which statement about administrative distance is true regarding the selection of routes in a routing table?

Accepted Answer

The route with the lowest administrative distance is installed in the routing table.. When a router receives multiple routes to the same destination from different routing protocols, the route with the lowest administrative distance is installed in the routing table, regardless of metric.

Answer

Routes with higher administrative distance are always preferred.

Answer

Administrative distance is only considered when metrics are equal.

Answer

Administrative distance is used to select the best path within the same routing protocol.

Question 3

An engineer configures a DMVPN Phase 2 network. Spoke routers can communicate with the hub, but spoke-to-spoke tunnels do not form. The NHRP registration is successful, and the hub has the spoke's NBMA address. Which is the most likely explanation?

Accepted Answer

The spoke routers are missing the `ip nhrp redirect` command on the hub.. In DMVPN Phase 2, spoke-to-spoke tunnels require that the spoke routers have a route to the remote spoke's tunnel IP via the hub, and that the hub has NHRP redirect enabled. Without the redirect, the spoke does not know to initiate a direct tunnel.

Answer

The spoke routers have different tunnel keys configured.

Answer

The spoke routers are using the same NHRP authentication string.

Answer

The hub router has a lower MTU on the physical interface, causing fragmentation.

Question 4

Consider this EIGRP configuration on router R5:

interface GigabitEthernet0/0
 ip summary-address eigrp 100 10.10.0.0 255.255.0.0 5

router eigrp 100
 network 10.0.0.0

What is the effect of the 'ip summary-address eigrp' command on interface GigabitEthernet0/0?

Accepted Answer

It creates a summary route 10.10.0.0/16 with administrative distance 5, advertised only out GigabitEthernet0/0.. The interface-level 'ip summary-address eigrp' command creates a summary route that is advertised out that specific interface. The optional administrative distance (5) sets the distance for the summary route.

Answer

It creates a summary route 10.10.0.0/16 with metric 5, advertised out all interfaces.

Answer

It creates a summary route 10.10.0.0/16 and suppresses all more specific routes globally.

Answer

It creates a summary route 10.10.0.0/16 and redistributes it into other routing protocols.

Question 5

A network engineer is troubleshooting a BGP route summarization issue. Router R1 is configured with the 'aggregate-address 192.168.0.0 255.255.252.0' command without any keywords. The engineer notices that the ISP neighbor is receiving both the aggregate route and the more specific routes (192.168.0.0/24, 192.168.1.0/24, etc.), causing the ISP to prefer the specific routes. What should the engineer do to ensure the aggregate route is preferred?

Accepted Answer

Add the 'summary-only' keyword to the aggregate-address command.. By default, BGP prefers more specific routes over less specific ones. To make the aggregate route preferred, the engineer can use the 'summary-only' keyword to suppress specific routes, or use attributes like AS_PATH to make the aggregate more attractive.

Answer

Remove the network statements for the specific subnets from the BGP process.

Answer

Configure a route-map to set a higher local preference on the aggregate route.

Answer

Use the 'aggregate-address' command with the 'as-set' keyword.

Question 6

A network engineer runs the following command on Router R1:

R1# show ip eigrp topology 10.0.0.0 255.255.252.0

IP-EIGRP (AS 100): Topology entry for 10.0.0.0/22
  State: Passive, Origin: Internal, Metric [90/2172416], Tag 0
  Number of successors: 1
  FD is 2172416, Serno: 5
  Route is Summary
  Advertised by R2 (via Serial0/0/0)
  Reply status: 0

Based on this output, what is true about the route 10.0.0.0/22?

Accepted Answer

The route is a summary route learned from R2.. The 'Route is Summary' line indicates this is a summary route in the EIGRP topology table. The output shows it is passive and has a successor, confirming it is a valid summary route.

Answer

The route is a summary route generated by R1.

Answer

The route is an external route redistributed into EIGRP.

Answer

The route is in active state and being queried.

Question 7

An engineer configures Flexible NetFlow on a Cisco router to monitor traffic on GigabitEthernet0/1. The flow record is defined with 'match ipv4 source address' and 'collect counter bytes'. The flow exporter sends data to 192.168.1.10:2055. After applying the monitor to the interface, 'show flow monitor name MONITOR cache' shows zero entries. What is the most likely root cause?

Accepted Answer

The flow monitor is applied in the wrong direction.. Flexible NetFlow requires a flow monitor to be applied to an interface in the correct direction (ingress or egress). If the direction is not specified, the default is ingress. If traffic is only egress, the monitor will not capture any flows.

Answer

The flow exporter is not configured with a source interface.

Answer

The flow record does not include 'match ipv4 protocol'.

Answer

The collector is unreachable, causing the router to stop caching flows.

Question 8

Given this partial configuration on router R6:

router bgp 65000
 neighbor 192.168.1.1 remote-as 65001
 address-family ipv4
  network 172.16.0.0 mask 255.255.0.0
  aggregate-address 172.16.0.0 255.255.0.0

What is missing if the administrator wants to ensure that only the aggregate route is advertised to neighbor 192.168.1.1?

Accepted Answer

The 'summary-only' keyword is missing from the aggregate-address command.. The aggregate-address command without the summary-only keyword will advertise both the aggregate and the more specific routes. To suppress the specifics, the summary-only keyword is required.

Answer

The 'network' command should be removed.

Answer

The 'synchronization' command must be enabled.

Answer

The 'neighbor 192.168.1.1 route-map' command is needed.

Question 9

An engineer configures IP SLA with a UDP jitter operation to monitor VoIP quality between two routers. The operation shows 'OverThreshold' in the show ip sla statistics output, but the engineer notices that the IP SLA responder on the remote router is configured with a control port that does not match the default. Which is the most likely explanation?

Accepted Answer

The IP SLA initiator must be configured with the 'control' keyword to specify the non-default control port on the responder.. IP SLA UDP jitter operations require the IP SLA responder to be configured with the correct control port; if the responder uses a non-default control port, the IP SLA initiator must be configured to use that port via the 'control' keyword under the IP SLA operation, otherwise the operation fails or produces incorrect results.

Answer

The IP SLA responder control port mismatch causes the operation to use a different port, but the jitter calculation is unaffected.

Answer

The IP SLA responder automatically adjusts its control port to match the initiator's request.

Answer

The UDP jitter operation does not use the control port; it only uses the destination port for jitter probes.

Question 10

A network engineer configures NetFlow on a router using the legacy 'ip flow-export' commands. After applying 'ip route-cache flow' on an interface, 'show ip flow export' shows packets being sent, but the collector reports that all flows have a source IP of the router's management interface instead of the actual source IPs. What is the most likely cause?

Accepted Answer

The 'ip flow-export source' command is set to the management interface, which becomes the source IP of export packets.. In legacy NetFlow, the 'ip flow-export source' command sets the source IP of export packets, not the flow data. The symptom described is normal; the collector sees the source IP of the export packets, not the flow source IPs. However, if the collector is misconfigured to interpret the export source as flow source, that is a collector issue. But more likely, the engineer is misreading the collector output. The question tests understanding that export source IP is not the flow source.

Answer

The router is performing NAT on the flow data before exporting.

Answer

The flow record is configured to match the router's interface IP as the source.

Answer

The collector is misconfigured to display the export packet source instead of the flow source.

Question 11

Which OSPF LSA type is used to advertise a summary route for a network outside the area but within the same OSPF domain?

Accepted Answer

Type 3. Type 3 LSAs (Summary LSAs) are generated by Area Border Routers (ABRs) to advertise inter-area routes.

Answer

Type 1

Answer

Type 2

Answer

Type 5

Question 12

A network engineer runs the following command on Router R1:

R1# show flow monitor FLOW-MONITOR-1 cache format table

Cache type:                               Normal
Cache size:                               1000
Current entries:                          500
High Watermark:                           800

Flows added:                              15000
Flows aged:                               14500
  - Active timeout (1800 secs)           12000
  - Inactive timeout (15 secs)           2500
  - Event aged                           0
  - Watermark aged                       0
  - Emergency aged                       0

Based on this output, what is a valid conclusion?

Accepted Answer

Most flows are long-lived, as indicated by the high number of active timeout expirations.. The cache has 500 current entries, with many flows added and aged. The high watermark of 800 indicates the cache has been near full, but no emergency aging occurred. The active timeout accounts for most aging, meaning flows are long-lived.

Answer

The cache is experiencing packet drops due to overflow.

Answer

The inactive timeout is set too high at 15 seconds.

Answer

The cache size should be increased to 2000 entries.

Question 13

In EIGRP, what is the default behavior of auto-summary in IOS-XE versions 15.0 and later?

Accepted Answer

Auto-summary is disabled by default.. Cisco IOS-XE 15.0 and later have auto-summary disabled by default for EIGRP, unlike older IOS versions where it was enabled by default.

Answer

Auto-summary is enabled by default.

Answer

Auto-summary is enabled only for EIGRP named mode.

Answer

Auto-summary is disabled only for EIGRP classic mode.

Question 14

What is the default OSPF reference bandwidth used in the cost calculation formula on Cisco IOS?

Accepted Answer

100 Mbps. The default reference bandwidth is 100 Mbps, meaning the cost is calculated as 100,000,000 / interface bandwidth in bps.

Answer

10 Mbps

Answer

1000 Mbps

Answer

1 Gbps

Question 15

Which TWO statements correctly describe the behavior of EIGRP route summarization when using the 'summary-address' command under an interface? (Choose TWO.)

Accepted Answer

A summary route is advertised with the metric equal to the best metric among the component routes.. EIGRP route summarization using the interface-level 'summary-address' command creates a local discard route to prevent routing loops, suppresses more specific routes from being advertised out that interface, and does not automatically summarize connected routes unless they are redistributed. The summary route is advertised with the metric of the best component route, and the administrative distance of the summary is set to 5 by default, not 90.

Answer

The summary route is automatically assigned an administrative distance of 90 by default.

Answer

The 'summary-address' command also summarizes connected routes that fall within the summary range.

Answer

More specific routes are still advertised out the same interface even after the summary is configured.