300-410 Route Summarization Practice Test 2 — 15 Questions

Question 1

A network engineer runs the following command on Router R1:

R1# show ip bgp neighbors 10.1.1.1 advertised-routes

BGP table version is 10, local router ID is 1.1.1.1
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
x best-external, a additional-path, c RIB-compressed,
Origin codes: i - IGP, e - EGP, ? - incomplete

Network          Next Hop            Metric LocPrf Weight Path
*> 10.0.0.0/8       0.0.0.0                  0         32768 i
*> 10.1.0.0/16      0.0.0.0                  0         32768 i
*> 10.1.1.0/24      0.0.0.0                  0         32768 i
*> 10.1.2.0/24      0.0.0.0                  0         32768 i

Based on this output, what is a problem with the BGP advertisements?

Accepted Answer

The router is advertising overlapping prefixes, including both summary and specific routes.. The router is advertising both a summary route (10.0.0.0/8) and more specific routes (10.1.0.0/16, 10.1.1.0/24, etc.), which defeats the purpose of summarization and can cause routing loops or suboptimal routing.

Answer

The router is not advertising any routes.

Answer

The router is only advertising the summary route.

Answer

The router is using incorrect next-hop.

Question 2

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 3

A network engineer runs the following command on Router R1:

R1# show ip eigrp topology summary

IP-EIGRP Topology Table for AS(100)/ID(1.1.1.1)
Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
       r - reply Status, s - sia Status

P 10.0.0.0/8, 1 successors, FD is 2812416, serno 10
    via Summary (2812416/0), Null0
P 10.0.0.0/24, 1 successors, FD is 2172416, serno 5
    via 192.168.1.2 (2172416/2812416), GigabitEthernet0/0
P 10.0.1.0/24, 1 successors, FD is 2172416, serno 6
    via 192.168.1.2 (2172416/2812416), GigabitEthernet0/0

Based on this output, what is the purpose of the route 10.0.0.0/8 via Null0?

Accepted Answer

It is a discard route to prevent routing loops.. The route 10.0.0.0/8 via Null0 is a summary route created by the 'summary-address' command in EIGRP, used to prevent routing loops by discarding packets that do not match more specific routes.

Answer

It is a default route for unknown destinations.

Answer

It is a route learned from a neighbor.

Answer

It is a connected route.

Question 4

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 5

Given the following OSPF configuration on router R2:

router ospf 1
 network 10.0.0.0 0.255.255.255 area 0
 area 0 range 10.0.0.0 255.255.252.0

Which statement is true about this configuration?

Accepted Answer

Router R2 will advertise a summary route 10.0.0.0/22 into area 0 from other areas.. The 'area range' command is used for inter-area route summarization on an ABR. It summarizes routes from one area into another, but only if the router is an ABR.

Answer

Router R2 will summarize routes from area 0 into other areas.

Answer

Router R2 will create a static route for 10.0.0.0/22.

Answer

Router R2 will filter all routes not within 10.0.0.0/22.

Question 6

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 7

Review the following OSPF configuration on router R4:

router ospf 1
 network 10.0.0.0 0.255.255.255 area 0
 area 1 range 10.0.0.0 255.255.255.0

What is missing or incorrect in this configuration for proper route summarization?

Accepted Answer

The router must have interfaces in area 1 for the summarization to take effect.. The area range command is used on an ABR to summarize routes from one area into another. Here, area 1 is specified, but router R4 only has network statements in area 0, so it is not an ABR for area 1. The command will have no effect.

Answer

The mask should be 0.0.0.255 instead of 255.255.255.0.

Answer

The command should be 'summary-address' instead of 'area range'.

Answer

The network statement should include area 1.

Question 8

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 9

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 10

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 11

In EIGRP, what is the default administrative distance of a summary route created with the 'ip summary-address eigrp' command?

Accepted Answer

5. By default, EIGRP summary routes have an administrative distance of 5, which is lower than the default distance of 90 for internal EIGRP routes.

Answer

90

Answer

170

Answer

1

Question 12

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 13

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 14

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 15

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.