300-410 Practice Test 23 — 15 Questions

Question 1

What is the default maximum number of paths that BGP can install in the routing table using the 'maximum-paths' command in Cisco IOS?

Accepted Answer

1. By default, BGP installs only one best path (maximum-paths 1). This can be increased to allow load balancing, but the default is 1.

Answer

2

Answer

4

Answer

6

Question 2

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

Accepted Answer

5000 ms. The default timeout for IP SLA operations is 5000 milliseconds (5 seconds). If no response is received within this time, the probe is considered failed.

Answer

1000 ms

Answer

10000 ms

Answer

60000 ms

Question 3

According to Cisco IOS default behavior, if a router learns the same route via both RIP and OSPF, which route will be installed in the routing table?

Accepted Answer

The OSPF route, because OSPF has a lower administrative distance.. OSPF has a default AD of 110, RIP has 120. Lower AD is preferred, so OSPF route is installed.

Answer

The RIP route, because RIP has a lower metric.

Answer

Both routes are installed, and load balancing occurs.

Answer

Neither route is installed; the router will use a default route.

Question 4

An engineer is troubleshooting a routing loop between two routers. R1 and R2 are running both OSPF and EIGRP. R1 learns the prefix 172.16.1.0/24 via OSPF with AD 110 and via EIGRP internal with AD 90. The engineer notices that R1 installs the EIGRP route, but traffic to 172.16.1.0/24 is being dropped. What is the most likely issue?

Accepted Answer

The EIGRP route is a summary route pointing to a null0 interface.. EIGRP internal routes have AD 90, which is lower than OSPF's 110, so EIGRP is preferred. However, if the EIGRP route points to a next-hop that is not reachable or is a backup path, traffic may be dropped. The root cause could be that the EIGRP route is learned via a secondary path that is not optimal or has a next-hop issue.

Answer

The OSPF route has a better metric, but the EIGRP route is preferred due to lower AD.

Answer

The OSPF route has a higher AD because it is a type 5 LSA.

Answer

The EIGRP route is an external route with AD 170.

Question 5

A network engineer is troubleshooting a multi-homed BGP setup. R1 receives the prefix 10.1.1.0/24 from two eBGP peers: R2 (AS 100) and R3 (AS 200). The engineer configures the distance bgp 20 20 20 command on R1 to make all BGP routes have the same AD. However, R1 still prefers the route from R2 over R3. What is the most likely reason?

Accepted Answer

The route from R2 has a higher local preference than the route from R3.. The distance bgp command sets AD for eBGP, iBGP, and local routes. With AD equal, the router uses other BGP path attributes, such as local preference, AS path length, or MED. The most common tie-breaker is local preference (default 100) or the oldest route.

Answer

The route from R2 has a lower MED than the route from R3.

Answer

The route from R2 is the oldest BGP route.

Answer

The AS path for the route from R2 is shorter than that from R3.

Question 6

An engineer is troubleshooting a route redistribution issue between OSPF and EIGRP. R1 runs both protocols and redistributes OSPF into EIGRP. The engineer notices that OSPF routes redistributed into EIGRP have an AD of 170, but some routes from OSPF are not being redistributed. What is the most likely cause?

Accepted Answer

The OSPF routes are not in the routing table because they are overridden by a static route with AD 1.. Redistribution into EIGRP requires matching routes; by default, only routes in the routing table are redistributed. If OSPF routes are not in the routing table because they are overridden by another protocol with lower AD, they will not be redistributed.

Answer

The OSPF routes have a higher metric than the EIGRP routes.

Answer

The redistribute ospf 1 metric 10000 command is missing.

Answer

The OSPF routes are external type 2, which are not redistributed by default.

Question 7

A network engineer configures IP SLA to track a BGP next-hop for a backup path. Router R1 has:

ip sla 7
 icmp-echo 192.168.3.3 source-ip 10.0.0.1
 frequency 5
ip sla schedule 7 life forever start-time now

track 7 ip sla 7 reachability

router bgp 65001
 neighbor 192.168.3.3 remote-as 65003
 neighbor 192.168.3.3 fall-over bfd
 neighbor 192.168.3.3 track 7

But when the link to 192.168.3.3 goes down, the BGP session resets after 5 seconds, but the backup route is not used immediately. What is the root cause?

Accepted Answer

The BGP fall-over bfd overrides the track, so the BGP session resets via BFD, but the track remains up, preventing the backup route from being installed.. The BGP fall-over bfd and track 7 are both configured. When the link goes down, BFD detects the failure quickly and resets the BGP session. However, the track 7 might still be up because the IP SLA probe might be successful via an alternate path, so the tracked route is not removed. The correct answer is that the track 7 is not used because BFD takes precedence, and the track does not influence the route removal.

Answer

The IP SLA frequency is too low, so the track does not detect the failure quickly enough.

Answer

The backup route has a higher administrative distance, so it is not installed until the primary route is removed, but the primary route is still present.

Answer

The track 7 is not applied to the BGP neighbor correctly; it should be under the address-family.

Question 8

A network engineer runs the following command to troubleshoot an IP SLA issue:

R1# show ip sla statistics 10

Round Trip Time (RTT) for Index 10
   Latest RTT: 12 ms
   Latest RTT (milliseconds): 12
   Latest RTT (microseconds): 12000
   Last operation start time: 12:34:56.789 UTC Mon Mar 1 2021
   Last operation return code: OK
   Number of successes: 100
   Number of failures: 0
   Operation time to live: Forever

What does this output indicate?

Accepted Answer

The IP SLA operation is working correctly with no failures.. This output shows the operational state of IP SLA operation 10. The 'Latest RTT' of 12 ms, 'return code: OK', and 100 successes with 0 failures indicate the probe is functioning correctly.

Answer

The IP SLA operation has failed because the RTT is too low.

Answer

The IP SLA operation has timed out and needs to be reconfigured.

Answer

The IP SLA operation is not configured for this index.

Question 9

Which IP SLA operation type is specifically designed to measure one-way delay, jitter, and packet loss using UDP packets with sequence numbers and timestamps?

Accepted Answer

UDP Jitter. The UDP Jitter operation (type 3) sends UDP packets with embedded sequence numbers and timestamps to measure one-way delay, jitter, and packet loss between source and destination.

Answer

UDP Echo

Answer

ICMP Path Echo

Answer

TCP Connect

Question 10

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

Accepted Answer

5000 ms. The default threshold for an IP SLA operation is 5000 milliseconds (5 seconds). This is the value above which the operation is considered to have exceeded a tolerable delay, triggering reaction conditions.

Answer

1000 ms

Answer

10000 ms

Answer

No default threshold

Question 11

A network engineer is troubleshooting a redistribution issue between EIGRP and OSPF. Router R1 redistributes EIGRP routes into OSPF. The engineer configured a summary route 10.0.0.0/8 using the 'summary-address' command under the OSPF process. After the configuration, OSPF neighbors lose connectivity to the 10.1.0.0/16 subnet, which is one of the component routes. What is the most likely cause?

Accepted Answer

The summary route 10.0.0.0/8 is not being generated because the component routes are not all present in the OSPF database.. The issue is that the summary-address command in OSPF can suppress the advertisement of more specific routes, but if the summary route is not installed due to a missing component or metric issue, it can cause a routing black hole.

Answer

The summary-address command on R1 is configured with the 'tag' keyword, causing the summary to be ignored by other routers.

Answer

The OSPF neighbor relationship is down due to a mismatch in area IDs.

Answer

The engineer forgot to configure the 'network' command for the summary route under OSPF.

Question 12

In OSPF, what is the default metric for a Type 3 summary LSA generated by an ABR using the 'area range' command?

Accepted Answer

The lowest metric among the summarized routes.. The default metric for a Type 3 summary LSA is the lowest metric among the component routes being summarized.

Answer

The highest metric among the summarized routes.

Answer

The sum of all metrics.

Answer

The metric is set to 1 by default.

Question 13

What is the default administrative distance for a route learned via the Border Gateway Protocol (BGP) from an external peer (eBGP)?

Accepted Answer

20. eBGP routes have a default administrative distance of 20, which is lower than iBGP's default AD of 200.

Answer

200

Answer

170

Answer

1

Question 14

What is the default administrative distance for a static route pointing to an interface (e.g., 'ip route 10.0.0.0 255.0.0.0 GigabitEthernet0/1')?

Accepted Answer

0. A static route configured with an exit interface (not a next-hop IP) has a default AD of 0, because it is treated as a directly connected route. However, if a next-hop IP is specified, the default AD is 1.

Answer

1

Answer

5

Answer

110

Question 15

Which THREE symptoms indicate that route summarization may be causing routing issues in a network? (Choose THREE.)

Accepted Answer

Suboptimal routing paths are observed for certain destinations.. Route summarization can cause suboptimal routing because the summary route may point to a less specific path. It can also cause black holes if the summary route is advertised but the specific subnets are not reachable. Additionally, summarization can hide more specific routes, leading to routing loops if the summary route is less specific and points to a router that does not have the specific subnet. High CPU usage is not a direct symptom of summarization issues, and duplicate IP addresses are unrelated.

Answer

High CPU utilization on routers due to frequent SPF calculations.

Answer

Duplicate IP addresses are detected in the network.