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Redistribution Quiz

July 24th, 2020 Go to comments

Question 1

Refer to the exhibit. An engineer is trying to redistribute OSPF to BGP, but not all of the routes are redistributed. What is the reason for this issue?

Router#show ip route ospf
--output omitted--
Gateway of last resort is not set
  10.0.0.0/24 is subnetted, 1 subnets
O E2      10.0.0.0 [110/20] via 192.168.12.2, 00:00:33, Ethernet0/0
O   192.168.3.0/24 [110/20] via 192.168.12.2, 00:00:43, Ethernet0/0
Router#
Router#show ip bgp
--output omitted--
    Network          	Next Hop         Metric LocPrf Weight Path         
*>  192.168.1.1/32	0.0.0.0               0         32768  ?
*>  192.168.3.0 	192.168.12.2         20         32768  ?
*>  192.168.12.0	0.0.0.0               0         32768  ?
Router#show running-config | section router bgp
router bgp 65000
 bgp log-neighbor-changes
 redistribute ospf 1
Router#
A.
B.
C.
D.

Question 2

Refer to the exhibit The output of the trace from R5 shows a loop in the network.

Redistribute_Trace.jpg

R1
router eigrp 1
redistribute connected
network 10.1.12.1 0.0.0.0
————————————–
R3
router ospf 1
redistribute eigrp 1
network 10.1.35.3 0.0.0.0 area 0
————————————–
R4
router eigrp 1
redistribute ospf 1 metric 2000000 1 255 1 1500
!
router ospf 1
network 10.1.45.4 0.0.0.0 area 0

R5#traceroute 10.1.1.1

Type escape sequence to abort.
Tracing the route to 10.1.1.1

1 10.1.35.3 80 msec 44 msec 20 msec
2 10.1.23.2 44 msec 104 msec 64 msec
3 10.1.24.4 44 msec 64 msec 40 msec
4 10.1.45.5 24 msec 40 msec 20 msec
5 10.1.35.3 92 msec 144 msec 147 msec
6 10.1.23.2 103 msec 77 msec 88 msec
—output omitted—

Which configuration prevents this loop?

Option A
R3
router ospf 1
redistribute eigrp 1 subnets route-map SET-TAG
!
route-map SET-TAG permit 10
set tag 1

R4
router eigrp 1
redistribute ospf 1 metric 2000000 1 255 1 1500 route-map FILTER-TAG
!
route-map FILTER-TAG deny 10
match tag 1
!
route-map FILTER-TAG permit 20

 Option B
R3
router eigrp 1
redistribute ospf 1 subnets route-map SET-TAG
!
route-map SET-TAG permit 10
set tag 1

R4
router eigrp 1
redistribute ospf 1 metric 2000000 1 255 1 1500 route-map FILTER-TAG
network 10.1.24.4 0.0.0.0
!
route-map FILTER-TAG deny 10
match tag 1
!
route-map FILTER-TAG permit 20
Option C
R3
router ospf 1
redistribute eigrp 1 subnets route-map SET-TAG
!
route-map SET-TAG permit 10
set tag 1

R4
router eigrp 1
redistribute ospf 1 metric 2000000 1 255 1 1500 route-map FILTER-TAG
!
route-map FILTER-TAG permit 10
match tag 1

 Option D
R3
router ospf 1
redistribute eigrp 1 subnets route-map SET-TAG
!
route-map SET-TAG deny 10
set tag 1

R4
router eigrp 1
redistribute ospf 1 metric 2000000 1 255 1 1500 route-map FILTER-TAG
!
route-map FILTER-TAG deny 10
match tag 1

 

A.
B.
C.
D.

Question 3

Refer to Exhibit. Which statement about redistribution from BGP into OSPF process 10 is true?

router ospf 10
 router-id 192.168.1.1
 log-adjacency-changes
 redistribute bgp 1 subnets route-map BGP-TO-OSPF
!
route-map BGP-TO-OSPF deny 10
 match ip address 50 
route-map BGP-TO-OSPF permit 20
!
access-list 50 permit 172.16.1.0 0.0.0.255
A.
B.
C.
D.

Question 4

Refer to the exhibit. Which routes from OSPF process 5 are redistributed into EIGRP?

router eigrp 1
redistribute ospf 5 match external route-map OSPF-TO-EIGRP
metric 10000 2000 255 1 1500
route-map OSPF-TO-EIGRP
match ip address TO-OSPF
A.
B.
C.
D.

Question 5

Which two statements about redistributing EIGRP into OSPF are true? (Choose two)

A.
B.
C.
D.
E.
F.

Question 6

Refer to the exhibit. Which subnet is redistributed from EIGRP to OSPF routing protocols?

Redistribution_EIGRP_OSPF_Prefix.jpg

R3 
router ospf 100
 redistribute eigrp 100 subnets route-map OSPF-TAG-1

ip prefix-list OSPF-TAG-PRF seq 5 deny 10.1.0.0/16 le 24
!
ip prefix-list OSPF-TAG-PRF-1 seq 5 permit 10.2.0.0/18 le 24
!
route-map OSPF-TAG-1 deny 5
 match ip address prefix-list OSPF-TAG-PRF
 set tag 40
!
route-map OSPF-TAG-1 permit 10
 match ip address prefix-list OSPF-TAG-PRF-1
 set tag 80
!
A.
B.
C.
D.

Question 7

Refer to the exhibit. After redistribution is enabled between the routing protocols, PC2, PC3, and PC4 cannot reach PC1. Which action can the engineer take to solve the issue so that all the PCs are reachable?

Redistribution_EIGRP_OSPF.jpg

A.
B.
C.
D.

Question 8

Refer to the exhibit. Which statement about R1 is true?

R1 (config)#route-map ADD permit 20
R1 (config-route-map)#set tag 1
R1 (config)#router ospf 1
R1 (config-router)#redistribute rip subnets route-map ADD
A.
B.
C.
D.

 

Comments (5) Comments
  1. Got it all correct
    October 16th, 2020

    I got it all correct but it only shows 90% in my score.

  2. networktut
    October 17th, 2020

    @Got it all correct: Thanks for your information, we have just fixed it!

  3. Rust
    November 18th, 2020

    Hi. I checked and found that right answer for question number 4 is A.
    R1 will send to R2 by RIP route 10.1.1.0/24 and AD 120, but when on R2 will come same route from R3 with AD 110, in will create loop. That’s why if you decrease AD from 120 to 100 this route will appear in RIB.
    B wrong answer, because OSPF on R3 doesn’t know about 10.1.1.0/24. R3 learned 10.1.1.0/24 from EIGRP. That’s why when you will redistribute OSPF to EIGRP this route will no appear on R4.

  4. Getafix
    November 25th, 2020

    Hi Rust,
    I thought about your answer but it seems to be incorrect (atleast as i see it). There are 2 redistributions happening.
    RIP–>EIGRP = R2 will inject 10.1.1.0/24 into EIGRP and prefix will reach R3 via EIGRP and AD 90
    EIGRP –> OSPF = R3 will inject 10.1.1.0/24 into OSPF and prefix will reach R2 via OSPF and AD 110

    OSPF–> EIGRP = R3 will inject 10.1.1.0/24 into EIGRP and prefix will reach back R2 via EIGRP and AD 90

    R2 now has 3 routes to choose from for 10.1.1.0/24 (RIP=120, OSPF= 110, EIGRP=90)

    Hence 90 route gets installed in the routing table. This AD 90 route is only received because it was being redistributed from OSPF back into EIGRP unfiltered.

    The correct answer would be to filter the routes from OSPF –> EIGRP

    I hope this makes sense

    Thanks

  5. Retake
    March 30th, 2022

    @Rust is correct. Answer is A.

    I’ve labbed it. Answer A corrects the issue which results in all PC on R2, R3, and R4 being able to reach PC1.

    @Getafix: The AD of EIGRP external routes is 170.

    @networktut:
    Please kindly review and update the correct answer for Q4. Thank you.