When configuring OSPF on a Tier-0 Gateway, which three of the following must match in order to establish a neighbor relationship with an upstream router? (Choose three.)
When configuring OSPF on a Tier-0 Gateway, which three of the following must match in order to establish a neighbor relationship with an upstream router? (Choose three.)
To establish a neighbor relationship in OSPF, certain parameters must match. The subnet mask must match to ensure that the interfaces are in the same IP network; mismatched subnet masks would prevent communication. The MTU of the Uplink must match because a mismatch would cause packets to be dropped, which is a common issue in neighbor adjacencies. Lastly, the Area ID must be the same to ensure both routers are in the same OSPF area, an essential aspect for OSPF to exchange routing information.
BCE. B and E answer can be found in the explanation of the ICM 4.0, p229. C answer can be found on the general prerequiste of the OSPF protocol to work correctly : https://www.computernetworkingnotes.com/ccna-study-guide/ospf-neighborship-condition-and-requirement.html