Exam JN0-351 topic 1 question 6 discussion

B: Using a routing policy to redistribute missing subnets as Type 5 LSAs, is a common and appropriate solution for advertising external routes into an OSPF domain. If the "missing subnets" are external to your OSPF domain, configuring redistribution and a routing policy on your ASBR ensures that those subnets are properly advertised as Type 5 LSAs and flooded throughout the OSPF network, making them reachable by all internal routers. C: This is the best option and would something like this: router ospf (custom id) redistribute connected subnets route-map (custom route-map-name)

C and D are correct

You can also configure an OSPF interface to be passive, to operate in passive traffic engineering mode, or to be a peer interface. A passive interface advertises its address, but does not run the OSPF protocol (adjacencies are not formed and hello packets are not generated). An interface operating in OSPF passive traffic engineering mode floods link address information within the autonomous system (AS) and makes it available for traffic engineering calculations.

Correct Answer C&D C. Configure and apply a routing policy that redistributes the connected Dallas and Denver subnets. A routing policy must be applied to redistribute the directly connected subnets (172.22.101.0/24 and 172.22.111.0/24) into OSPF. D. Enable the passive option on the OSPF interfaces that are connected to the Dallas and Denver subnets. Enabling the passive option ensures that the subnets are advertised without forming unnecessary OSPF adjacencies with the switches. Explanation of Incorrect Options A. Create static routes on the switches using the local vMX router's loopback interface for the next hop. This does not address the issue of OSPF not advertising the connected subnets. Static routes on switches are unrelated to OSPF advertisement. B. Configure and apply a routing policy that redistributes the Dallas and Denver subnets using Type 5 LSAs. Type 5 LSAs are used for external routes (e.g., redistributed static or BGP). These are internal, connected subnets that can be advertised using regular OSPF Type 1 or Type 3 LSAs.

B. Configure and apply a routing policy that redistributes the Dallas and Denver subnets using Type 5 LSAs. This is the most efficient and OSPF-compliant way to advertise the subnets. By redistributing the connected subnets as Type 5 LSAs, the routers will include these subnets in their OSPF database, allowing other OSPF routers to learn about them and route traffic accordingly. C. Configure and apply a routing policy that redistributes the connected Dallas and Denver subnets. This is also a valid solution, but it might not be as efficient as using Type 5 LSAs. Redistributing the connected subnets as Type 2 LSAs (network LSAs) will require the routers to maintain more information in their OSPF database, which can impact performance. However, it will still allow other OSPF routers to learn about the subnets and route traffic accordingly.

Why I think D is wrong? D. Enable the passive option on the OSPF interfaces that are connected to the Dallas and Denver subnets. This is not a correct approach. The passive option is used to prevent an interface from participating in OSPF neighbor relationships. In this case, we want the interfaces to participate in OSPF and advertise the connected subnets.

Answer BC B. Configure and apply a routing policy that redistributes the Dallas and Denver subnets using Type 5 LSAs. This is the most efficient and OSPF-compliant way to advertise the subnets. By redistributing the connected subnets as Type 5 LSAs, the routers will include these subnets in their OSPF database, allowing other OSPF routers to learn about them and route traffic accordingly. C. Configure and apply a routing policy that redistributes the connected Dallas and Denver subnets. This is also a valid solution, but it might not be as efficient as using Type 5 LSAs. Redistributing the connected subnets as Type 2 LSAs (network LSAs) will require the routers to maintain more information in their OSPF database, which can impact performance. However, it will still allow other OSPF routers to learn about the subnets and route traffic accordingly.

C,D are correct

I agree

I agree