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Question 570

SIMULATION

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Guidelines

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This is a lab item in which tasks will be performed on virtual devices.

• Refer to the Tasks tab to view the tasks for this lab item.

• Refer to the Topology tab to access the device console(s) and perform the tasks.

• Console access is available for all required devices by clicking the device icon or using the tab(s) above the console window.

• All necessary preconfigurations have been applied.

• Do not change the enable password or hostname for any device.

• Save your configurations to NVRAM before moving to the next item.

• Click Next at the bottom of the screen to submit this lab and move to the next question.

• When Next is clicked, the lab closes and cannot be reopened.

Topology

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Tasks

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Troubleshoot and resolve the issues to achieve these goals:

1. Ensure that R1 reaches the prefix 10.6.66.6 without any single point of failure in the path. Do not use a static route or policy-based routing to accomplish this.

2. Ensure that R1 loopback 1 reaches to R6’s loopback 1 by following the path through R1, R3, R5 to R6 and vice versa. Use metric values K1 = 100000, K2=1, K3=255, K4=10, K5=1500 to modify the default metric in EIGRP if required. Do not use a route-map.

3. Ensure that on R3, prefix 10.0.56.6/32 uses the SP1 to route to the Internet, whereas prefix 172.16.12.2/32 uses the SP2 to route to the Internet. Do not use BGP to accomplish this. Use the pre-configured route-maps SP1 and SP2 and modify to accomplish the task if required. Use the ping and trace commands from R6 and R2 to prefixes 209.165.202.132 and 209.165.202.128, respectively to verify the results.

    Correct Answer:

Discussion
Bombbear_W

So glad to see this simulation is finally added. Well done examtopics team and appreciated it.

bk989

I figured it out. R4 mutually redistributes EIGRP and OSPF into eachother before R3 does redistribution. After R3 does redistribution R3 has 2 paths to 10.6.66.6 network. R3 chooses EIGRP as it has lower administrative distance. However in the simlet we use distance command to make EIGRP distance higher, than external OSPF distance of 110. In my lab this is what it looks like, for EIGRP 1 and OSPF 1 process (I did not use process number of 10): router eigrp 1 network 10.0.35.3 0.0.0.0 network 10.3.3.0 0.0.0.255 network 10.3.33.0 0.0.0.255 redistribute bgp 1 metric 1 1 1 1 1 distance 125 0.0.0.0 255.255.255.255 66

bk989

R4 mutually redistributes before R3 does: router eigrp 1 network 10.0.46.4 0.0.0.0 network 10.4.4.0 0.0.0.255 network 10.4.44.0 0.0.0.255 redistribute ospf 1 metric 1 1 1 1 1 redistribute rip metric 1000000 1 255 10 1500 distance 125 0.0.0.0 255.255.255.255 66 eigrp router-id 4.4.4.4 Now because R3 has distance 125 command to 10.6.66.6, we see R3 chooses the path to R4, on the other side of the network. R3#show ip route <...........> D 10.5.5.0/24 [90/409600] via 10.0.35.5, 00:22:17, Ethernet0/1 D 10.5.55.0/24 [90/409600] via 10.0.35.5, 00:22:17, Ethernet0/1 O E2 10.6.6.0/24 [110/20] via 172.16.13.1, 00:05:05, Ethernet0/0 O E2 10.6.66.0/24 [110/20] via 172.16.13.1, 00:05:05, Ethernet0/0 Notice that for the 10.5.55.0/24 loopback of R5, R3 still chooses EIGRP 1 as it has lower AD, but since 10.6.66.0/24 has distance of 125 for EIGRP, R3 chooses the path to R4

bk989

The same is true for R1 as now R1 has best path through R4, as R3 never advertises the 10.6.66.6 route into OSPF from EIGRP distance 125, as it already has a route to 10.6.66.6 distance 110. R1#trace 10.6.66.6 source L0 Type escape sequence to abort. Tracing the route to 10.6.66.6 VRF info: (vrf in name/id, vrf out name/id) 1 172.16.12.2 6 msec 1 msec 5 msec 2 172.16.24.4 6 msec 5 msec 5 msec 3 10.0.46.6 6 msec 5 msec 5 msec

bk989

The above traceroute goes through R4 which is longer path. The question asks for R1 -->R3 --> R5 --> R6. When we issue this command on R3: R3(config)# R3(config-router)#no distance 125 0.0.0.0 255.255.255.255 66 Now R3 has 10.6.66.6 as a better route in eigrp compared to OSPF E2 route of R4, and redistributes it into OSPF 1 and installs it into LSDB. Now R3 has better route: R3#show ip ro *Jul 16 22:22:07.702: %SYS-5-CONFIG_I: Configured from console by console R3#show ip route <.......> D 10.5.5.0/24 [90/409600] via 10.0.35.5, 00:02:15, Ethernet0/1 D 10.5.55.0/24 [90/409600] via 10.0.35.5, 00:02:15, Ethernet0/1 D 10.6.6.0/24 [90/51379200] via 10.0.35.5, 00:02:15, Ethernet0/1 D 10.6.66.0/24 [90/51379200] via 10.0.35.5, 00:02:15, Ethernet0/1 And now R3 installs this into its OSPF LSDB and advertises it to R1.

bk989

Now R1 has the route advertised from R3. And the traceroute: R1#trace 10.6.66.6 Type escape sequence to abort. Tracing the route to 10.6.66.6 VRF info: (vrf in name/id, vrf out name/id) 1 172.16.13.3 20 msec 6 msec 5 msec 2 10.0.35.5 1 msec 6 msec 6 msec 3 10.0.56.6 6 msec 5 msec 5 msec

bk989

here is my config if you want to practice: R3: router eigrp 1 network 10.0.35.3 0.0.0.0 network 10.3.3.0 0.0.0.255 network 10.3.33.0 0.0.0.255 redistribute bgp 1 metric 1 1 1 1 1 eigrp router-id 3.3.3.3 ! router ospf 1 router-id 3.3.3.3 redistribute eigrp 1 subnets redistribute bgp 1 subnets network 10.3.3.0 0.0.0.255 area 0 network 10.3.33.0 0.0.0.255 area 0 network 172.16.13.3 0.0.0.0 area 0 default-information originate ! router bgp 1 bgp log-neighbor-changes redistribute eigrp 1 redistribute ospf 1 neighbor 209.165.200.226 remote-as 2 neighbor 209.165.201.1 remote-as 2 (the bgp is for the SP neighbors)

bk989

I cannot get the loop to work properly, as it did on the exam. When I pinged 10.66.6.6 from R1 source Loopback0/1 it goes to R6 without a loop. I am mutually redistributing on both R3 and R4, but this causes suboptimal routing, and not a routing loop ~ any suggestions?

Ivan_AGC

I got this SIM in my Exam, please pay attention to the ACL in my test the ACLs were already created and matched in the route map. The ACLs have a Deny for the networks 172.0.0.0 and 10.0.0.0. So you need to delete it before starting the configuration.

chaba7654321

Had this lab on the exam, pretty much the same - and the provided answer in config is pretty accurate. I had a different metric set under eigrp distance for 0.0.0.0 255.255.255.255, but removing it fixed the issue so not too important Used traceroute to troubleshoot flow as suggested

cloud29

Is that provided answer is correct?

LooserDragon

Be aware, because they can have different metrics on the routers on the real sim. Ensure that R6 takes the route through R5 instead of R4 (because the PBR won’t work that way). If it does, you can configure the link between R6 and R4 with lower bandwith OR the link between R6 and R5 with higher.