Selected Answer: A https://networklessons.com/cisco/ccie-routing-switching/troubleshooting-metric-redistribution Redistribution Rule: Never advertise prefixes from routing protocol X into Y and then back into X. Redistribution means going from one protocol (or routing domain) into the other protocol (or routing domain) with the redistribute command. It's easier to think about redistribution between different protocols. Answer "A" means something like this: router ospf 1 redistribute eigrp 100 subnets tag 20 route-map FILTER deny match tag 20 route-map FILTER permit router eigrp 100 redistribute ospf 1 metric 100000 1 255 1 1500 route-map FILTER 1)redistribute into ospf and set the tag 2)redistribute into eigrp and match the tag (with action deny) Set a tag so routes coming from a routing domain will not be redistributed back into that domain.

Selected Answer: B It is either A or B. However, for the routing to work between the two domains, the tagged routes need to be advertised first. So, for A, it says we are denying the tag into the new domain. While B says, we are denying the tag from the other domain coming back to the origin domain. To me, this is a language question and not technical.

Selected Answer: D This is not redistribution between routing protocols, only between ospf domains, so D.

Selected Answer: B B is the right answer

Selected Answer: A Redistribute Path (See a similar figure 17-6 on Page 678) EIGRP 100 R1 ---> R2 OSPF 1 (Redistribute into OSPF from EIGRP) EIGRP 100 R3 <---- R4 OSPF 1 (The same redistributed packets will be introduced into EIGRP from OSPF) R2 ==== router ospf 1 redistribute eigrp 100 subnet route-map FROM-EIGRP-TO-OSPF route-map FROM-EIGRP-TO-OSPF permit ip address match prefix-list PREFIX-TAG set tag 100 ip prefix-list PREFIX seq 10 permit 10.1.1.0/24 R4 === router eigrp 100 redistribute ospf metric 1000000 100 255 1 1500 route-map FROM-OSPF-TO-EIGRP route-map FROM-EIGRP-TO-EIGRP deny tag match 100 route-map FROM-EIGRP-TO-EIGRP permit

Wrong. You can have multiple OSPF processes on the same router and redistribute between them.

I think that the tag should be blocked when exiting the different domain, in order for the routes to become known to the different domain. So I'll go with B.

The correct answer is B

Selected Answer: A https://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/4170-ospfprocesses.html This seems like the same scenario.

Selected Answer: B I feel this question is more like "how good is your english" when we redistribute, it gets into that domain(IN) so we deny it on its way OUT of that current OSPF domain. my understanding with my level of english

Selected Answer: A A is right

OSPF Redistribution Between Different OSPF Processes - Filter Routes Based on Tags https://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/4170-ospfprocesses.html#anc16:~:text=be%20very%20difficult.-,Filter%20Routes%20Based%20on%20Tags,-There%20is%20a

Selected Answer: D Most comments forgot to read the question properly, it says "between multiple OSPF domains". Since redistribution is used to inject between different routing protocols, we will need to configure a route-map that matches and denies the same incoming route from a different OSPF domain.

Selected Answer: A the correct option is A: https://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/4170-ospfprocesses.html router ospf 1 redistribute ospf 2 subnet tag 1 distribute-list 1 route-map filter_domain2 in ! route-map filter_domain2 deny 10 match tag 2 route-map filter_domain2 permit 20 router ospf 2 redistribute ospf 1 subnet tag 2 distribute-list 1 route-map filter_domain1 in ! route-map filter_domain1 deny 10 match tag 1 route-map filter_domain1 permit 20

bro, your answer is wrong. try it in a lab

The key word in A is "inbound". This handles bad mutual redistribution on multiple routers. The other answers don't say exactly what the exit domains are. This may or may not reduce instability.

Selected Answer: A C and D are out because you can't add a tag with the network command. A says "inbound" which is why I'd choose A over B.

For example, it can't be B: Set a tag using the redistribute command toward a different domain and deny the matching tag when exiting from that domain. We set tag A-->B and exit B-->C won't prevent loop D is also wrong: Set a tag using the network command in a domain and use the route-map command to deny the matching tag when entering into a different domain I set tag as 20 in domain A and redistribute into domain B from domain A-->B then I deny all tagged routes and they never get redistributed to begin with.

Remember we can set tags with route-maps (distribute-lists etc) so if I set the tag in a distribute-list route-map in domain A, and deny the tag when entering from A-->B I never redistribute the route in the first place. So the answer is not D. It is A.

Selected Answer: A I feel like this is more of an english test question.

Selected Answer: B C and D are not valid commands, you don't tag with the network command. That leaves us with A or B. To me, A is wrong because the wording suggests you would be tagging outbound on one process and filtering that tag inbound on the other process. That would prevent routing between processes, not stop a loop. The goal is to redistribute routes from OSPF process 1 into process 2 and tag them during that redistribution. What you want to avoid is having those same tagged routes redistributed back from process 2 into process 1, which would create a routing loop. This means the filtering should happen when redistributing outbound from process 2, not inbound into it. Therefore, the wording of option A is misleading, and option B is technically more accurate.

Why isn't it D?

Selected Answer: D I dont see where it says in the question that the routes are redistributed, I think it is just an adjacency made with the network command. therefore D seems right.

router ospf 1 log-adjacency-changes redistribute eigrp 1 metric 10 metric-type 1 subnets tag 10 (right) ! R1(config-router)#network ? A.B.C.D Network number ! R1(config-router)#network 1.1.1.1 ? A.B.C.D OSPF wild card bits ! R1(config-router)#network 1.1.1.1 0.0.0.0 area 0 ? <cr> ! R1(config-router)#network 1.1.1.1 0.0.0.0 area 0 (that command doesn't exist)

A is the correct answer

Wrong. You can have multiple OSPF processes on the same router and redistribute between them.

As you said, the answer is A and this config shows that clearly: router ospf 1 redistribute ospf 2 subnet tag 1 route-map filter_domain2 distance ospf 2 external 200 ! route-map filter_domain2 deny 10 match tag 2 route-map filter_domain2 permit 20 router ospf 2 redistribute ospf 1 subnet tag 2 route-map filter_domain1 distance ospf 1 external 200 ! route-map filter_domain1 deny 10 match tag 1 route-map filter_domain1 permit 20 This is a good example of me redistributing my ospf process into another one and putting a tag on it, and in the route-map I'm gonna deny any kind of ospf redistribution from the other process that got this tag. It's kind of the same as redistribution between routing protocols, the theory is basically the same.

D. in this case could be referring to a sequential domain. area A --> area B --> area C Set tage area A, deny into area C. We typically won't solve suboptimal routing. The kyeword in option A is the "inbound" keyword. area A --> area B --> inbound area A (the other domain) we stop area A routes from getting redistributed into itself avoiding suboptimal routing

exactly my point.....A and B engineers would both come up with the same solution, just worded differently. i.e Inbound...exiting