300-410 Mock Exam 80 — 25 Questions

Question 1

A network engineer configures IP SLA tracking for a static route on a Cisco router. The IP SLA operation is configured with a threshold of 100 ms and a timeout of 5000 ms. The tracked object is configured with a delay of 5 seconds for both up and down transitions. The engineer notices that when the remote host becomes unreachable, the static route is not removed from the routing table immediately. Which is the most likely explanation?

Accepted Answer

The tracked object delay of 5 seconds for down transition causes a 5-second wait before the route is removed.. The IP SLA tracking delay configuration introduces a delay before the tracked object changes state; this is designed to prevent route flapping but can cause the static route to remain in the routing table for the configured delay period after the IP SLA operation fails.

Answer

The IP SLA operation is still in the 'pending' state and has not yet timed out.

Answer

The static route has a higher administrative distance than the IP SLA tracked route, so it remains preferred.

Answer

The IP SLA operation is configured with a frequency that is too low, causing a delay in detection.

Question 2

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 3

A network engineer runs the following command on Router R1:

R1# show ip eigrp interfaces detail GigabitEthernet0/0

IP-EIGRP interfaces for process 100

Interface                    Peers  Xmit Queue   Mean   Pacing Time   Multicast    Pending
                              Un/Reliable  SRTT   Un/Reliable   Flow Timer   Routes
Gi0/0                          1       0/0       10       0/10          50           0
  Hello interval: 5 sec, Hold time: 15 sec
  Split horizon is enabled
  Summary address: 10.0.0.0/8
  Next xmit serial <none>
  Un/reliable mcasts: 0/0  Un/reliable ucasts: 0/0
  Mcast exceptions: 0  CR packets: 0  ACKs suppressed: 0
  Retransmissions: 0  Retry timer: 15
  Hello packets sent: 100, received: 99

Based on this output, what is the purpose of the summary address configured on this interface?

Accepted Answer

It advertises a summary route 10.0.0.0/8 to neighbors.. The 'Summary address: 10.0.0.0/8' line shows that a manual summary route is configured on this interface, which will be advertised to EIGRP neighbors.

Answer

It filters all routes in the 10.0.0.0/8 range.

Answer

It redistributes connected routes.

Answer

It disables split horizon.

Question 4

Which of the following best describes the behavior of BGP when an 'aggregate-address' command is used without the 'summary-only' keyword?

Accepted Answer

The aggregate route is advertised, and all more specific routes are also advertised.. Without the summary-only keyword, BGP advertises both the aggregate route and the more specific routes that are in the BGP table.

Answer

Only the aggregate route is advertised.

Answer

The aggregate route is not advertised unless a network command exists for it.

Answer

The more specific routes are withdrawn from the BGP table.

Question 5

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 6

A network engineer configures Flexible NetFlow to export traffic statistics for a VRF named CUSTOMER_A. The configuration includes 'flow exporter EXPORTER' with destination 10.10.10.10:2055 and 'vrf CUSTOMER_A' under the exporter. The flow monitor is applied to the VRF interface. However, 'show flow monitor name MONITOR cache' shows no entries for VRF traffic. What is the most likely cause?

Accepted Answer

The flow monitor is applied to the global routing table interface instead of the VRF interface.. For VRF-aware NetFlow, the flow monitor must be applied using the 'ip flow monitor MONITOR input' command under the VRF interface, and the exporter must reference the VRF. A common mistake is forgetting to apply the monitor to the interface in the VRF context.

Answer

The exporter is missing the 'source' interface command.

Answer

The VRF is not configured with 'ip flow-export' commands.

Answer

The flow record does not match any VRF-specific fields.

Question 7

A network engineer runs the following command on Router R1:

R1# show ip route summary

IP routing table maximum-paths: 32
IP routing table has 15 routes, using 900 bytes of memory
  Number of prefixes:
       /8: 1, /16: 2, /20: 3, /24: 9
  Route types:
    Connected: 4, Static: 1, OSPF: 10
  Route sources:
    OSPF: 10, Connected: 4, Static: 1

Based on this output, what is a potential issue regarding route summarization?

Accepted Answer

There are too many /24 prefixes, suggesting poor summarization.. The routing table has many /24 prefixes (9), indicating that route summarization is not being used effectively, leading to a larger routing table.

Answer

The routing table is too small.

Answer

There are too many OSPF routes.

Answer

The routing table is empty.

Question 8

Consider the following partial EIGRP configuration on router R1:

router eigrp 100
 network 10.0.0.0
 network 192.168.1.0
 summary-address 10.0.0.0 255.255.255.0 5

What is the effect of the 'summary-address 10.0.0.0 255.255.255.0 5' command?

Accepted Answer

It creates a summary route 10.0.0.0/24 with an administrative distance of 5, advertised out all EIGRP-enabled interfaces.. The 'summary-address' command in EIGRP creates a summary route and advertises it out all interfaces enabled for EIGRP. The administrative distance value (5) is optional and sets the distance for the summary route.

Answer

It creates a summary route 10.0.0.0/24 and sets the metric to 5.

Answer

It creates a summary route 10.0.0.0/24 and suppresses more specific routes with a metric of 5.

Answer

It creates a summary route 10.0.0.0/24 with a tag of 5.

Question 9

Which TWO statements about route summarization in EIGRP are true? (Choose TWO.)

Accepted Answer

EIGRP automatic summarization is enabled by default for classful networks.. EIGRP supports manual summarization on any interface using the 'ip summary-address eigrp' command, and automatic summarization is enabled by default for classful networks. EIGRP does not support automatic summarization at the classful boundary for all networks; it is only for major network boundaries. Summarization in EIGRP does not require a route-map, and it can be configured on any interface, not just serial interfaces.

Answer

EIGRP supports automatic summarization for all types of networks, including discontiguous subnets.

Answer

Route summarization in EIGRP requires the use of a route-map to define the summary prefix.

Answer

Manual summarization can only be applied to serial interfaces.

Question 10

A network engineer configures IP SLA with an HTTP GET operation to monitor a web server. The operation shows 'Success' but the response time is extremely high. The engineer checks the web server and finds it is overloaded. The engineer wants to configure a threshold so that the IP SLA operation triggers a track object when the response time exceeds 500 ms. Which configuration change is required?

Accepted Answer

Configure the 'threshold' command under the IP SLA operation and use the 'track' command with 'threshold' keyword in the track object.. IP SLA HTTP operations measure response time, but to trigger a track object based on threshold violation, the engineer must configure the 'threshold' command under the IP SLA operation and then configure the track object to react to the 'threshold' state, not just the 'up/down' state. By default, track objects only track up/down, not threshold violations.

Answer

Configure the 'timeout' command to 500 ms; the track object will automatically react to timeouts.

Answer

Use the 'reaction' command under the IP SLA operation to trigger a trap; the track object cannot react to thresholds.

Answer

Configure the IP SLA operation with a lower frequency to get more samples; the track object will average the response time.

Question 11

An engineer notices that NetFlow export packets are being sent from a router but the collector reports missing data for certain flows. The engineer checks 'show ip flow export' and sees 'Exporting flows to 10.1.1.100 (2055)' with packets being sent. However, 'show flow monitor name MONITOR cache' shows many flows with zero byte counts. What is the most likely cause?

Accepted Answer

The flow record includes 'collect counter packets' but not 'collect counter bytes'.. If the flow record only collects packet counts but not byte counts, the byte counter will remain zero. This is a configuration error in the flow record definition.

Answer

The flow exporter is using UDP port 2055, but the collector expects TCP.

Answer

The router's CPU is overloaded, causing byte counters to not update.

Answer

The flow monitor is applied in egress direction, which does not support byte collection.

Question 12

A network engineer runs the following command on Router R1:

R1# show ip route 10.0.0.0 255.255.252.0 longer-prefixes

Routing entry for 10.0.0.0/22
  Known via "eigrp 100", distance 90, metric 2172416, type internal
  Last update from 192.168.1.2 on GigabitEthernet0/0, 00:00:10 ago
  Routing Descriptor Blocks:
  * 192.168.1.2, from 192.168.1.2, 00:00:10 ago, via GigabitEthernet0/0
      Route metric is 2172416, traffic share count is 1

Routing entry for 10.0.1.0/24
  Known via "eigrp 100", distance 90, metric 2812416, type internal
  Last update from 192.168.1.2 on GigabitEthernet0/0, 00:00:10 ago
  Routing Descriptor Blocks:
  * 192.168.1.2, from 192.168.1.2, 00:00:10 ago, via GigabitEthernet0/0
      Route metric is 2812416, traffic share count is 1

Based on this output, what is the effect of the summary route 10.0.0.0/22?

Accepted Answer

The summary route is not suppressing the more specific route 10.0.1.0/24.. The presence of both the summary route (10.0.0.0/22) and a more specific route (10.0.1.0/24) in the routing table indicates that the summary route is not suppressing the more specific routes, possibly due to a configuration issue or because the summary is not configured as a discard route.

Answer

The summary route is working correctly and suppressing all specifics.

Answer

The summary route has a better metric than the specific route.

Answer

The summary route is not installed in the routing table.

Question 13

Examine this BGP configuration on router R3:

router bgp 65001
 neighbor 10.1.1.1 remote-as 65002
 address-family ipv4
  network 192.168.0.0 mask 255.255.252.0
  aggregate-address 192.168.0.0 255.255.252.0 summary-only

What is the effect of the 'aggregate-address' command with the 'summary-only' keyword?

Accepted Answer

It advertises the aggregate 192.168.0.0/22 and suppresses all more specific routes from being advertised to neighbor 10.1.1.1.. The aggregate-address command creates an aggregate route in BGP. The summary-only keyword suppresses more specific routes from being advertised.

Answer

It advertises both the aggregate and all more specific routes.

Answer

It creates a static route for the aggregate.

Answer

It removes all more specific routes from the BGP table.

Question 14

An engineer configures IP SLA with an ICMP echo operation and tracks it with a static route. The IP SLA operation is configured with a source interface of Loopback0. The engineer notices that when the remote host becomes unreachable, the static route is removed, but when the remote host becomes reachable again, the static route is not reinstalled immediately. The show ip sla statistics shows the operation is 'Active' and 'Success'. Which is the most likely explanation?

Accepted Answer

The track object has a 'delay up' configured, causing a delay before the route is reinstalled.. When an IP SLA operation uses a source interface, the operation may fail if that interface is down, but more importantly, the track object may have a delay configured for up transitions. Additionally, the static route may have a higher administrative distance that prevents it from being reinstalled if another route to the same prefix exists. However, the most common edge case is that the track object has a 'delay up' configured, which delays the route installation after the operation recovers.

Answer

The static route has a higher administrative distance than the default route, so it is not installed.

Answer

The IP SLA operation uses a source interface that is not reachable from the remote host, causing asymmetric routing.

Answer

The IP SLA operation has a frequency that is too high, causing the router to ignore the results.

Question 15

Which TWO commands can be used to verify route summarization on a Cisco router running OSPF? (Choose TWO.)

Accepted Answer

show ip route summary. The 'show ip route summary' command provides a summary of the routing table including the number of routes and the memory used, while 'show ip ospf border-routes' displays the OSPF route table entries for ABRs and ASBRs, which can include summary routes. 'show ip protocols' does not directly show summarization details. 'show ip route' alone does not summarize. 'show ip ospf database' shows the LSDB, not the summarized routing table.

Answer

show ip protocols

Answer

show ip route

Answer

show ip ospf database

Question 16

A network engineer configures IP SLA with a UDP echo operation to monitor a remote server. The IP SLA responder is configured on the remote router. The engineer notices that the operation shows 'Timeout' intermittently, but standard UDP connectivity tests from the router to the server succeed. The engineer checks the IP SLA responder configuration and finds that the control port is set to a non-default value. Which is the most likely explanation?

Accepted Answer

The IP SLA initiator must be configured with the 'control' keyword to match the non-default control port on the responder.. IP SLA UDP echo operations require the IP SLA responder to be configured with the correct control port. If the responder uses a non-default control port, the initiator must be configured to use that port using the 'control' keyword under the IP SLA operation. Without this, the initiator uses the default control port (1967), causing communication failures and intermittent timeouts.

Answer

The IP SLA responder is not configured to respond to UDP echo requests from the initiator.

Answer

The UDP echo operation uses a different protocol than standard UDP, causing packet drops.

Answer

The IP SLA operation has a threshold that is too low, causing the operation to time out.

Question 17

An engineer configures Flexible NetFlow on a router to monitor both IPv4 and IPv6 traffic. The flow record is defined with 'match ipv4 source address' and 'match ipv6 source address'. After applying the monitor to an interface, 'show flow monitor name MONITOR cache' shows only IPv4 flows. What is the most likely cause?

Accepted Answer

The flow record cannot combine IPv4 and IPv6 match fields; separate monitors are needed.. A single flow record cannot mix IPv4 and IPv6 match fields; they are separate address families. The engineer must create two separate flow monitors—one for IPv4 and one for IPv6—and apply both to the interface.

Answer

IPv6 traffic is not present on the interface.

Answer

The interface does not have IPv6 enabled.

Answer

The flow exporter is not configured to send IPv6 flows.

Question 18

Which TWO configuration steps are required to implement manual route summarization in OSPF on an ABR? (Choose TWO.)

Accepted Answer

Configure the 'area area-id range network mask' command under router OSPF configuration.. In OSPF, manual summarization on an ABR is done using the 'area range' command under router configuration mode, which summarizes routes from one area into another. The summary address must be within the range of networks in the area. The 'summary-address' command is used for external routes on ASBRs, not for inter-area summarization. 'network' commands define interfaces, not summarization. 'default-information originate' is for default routes.

Answer

Use the 'summary-address network mask' command under router OSPF configuration.

Answer

Apply the 'ip summary-address ospf' command under the interface connecting to the backbone.

Answer

Configure a 'network' statement that matches the summary address.

Question 19

An engineer configures IP SLA with an ICMP echo operation and uses it to track a static default route. The engineer also configures a backup static route with a higher administrative distance. The IP SLA operation is configured with a timeout of 2000 ms and a frequency of 5 seconds. The engineer notices that when the primary route is removed due to IP SLA failure, the backup route is installed, but when the IP SLA operation recovers, the primary route is not reinstalled. The show ip route shows the backup route still present. Which is the most likely explanation?

Accepted Answer

The track object has a 'delay up' configured, causing a delay before the primary route is reinstalled.. When a tracked static route is removed, the backup route with higher AD is installed. When the IP SLA operation recovers, the track object goes up, and the primary route should be reinstalled. However, if the IP SLA operation recovers but the track object has a delay up configured, or if the primary route's AD is not lower than the backup route, the primary route may not be reinstalled. In this scenario, the most likely edge case is that the track object has a 'delay up' configured, which delays the route installation.

Answer

The IP SLA operation has a frequency that is too low, causing a delay in detection of recovery.

Answer

The backup static route has a lower administrative distance than the primary route.

Answer

The IP SLA operation is still in the 'pending' state and has not yet recovered.

Question 20

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.