4A0-112 Exam Dumps : Nokia IS-IS Routing Protocol

In a single-area link-state routing protocol (such as OSPF), routers share specific information about the network topology, not their entire routing table. They exchangelink-state advertisements (LSAs)that contain information about their directly connected interfaces and their state, allowing other routers to build a consistent view of the network.

In the configuration on router R1, the static route is defined with the next-hop IP address of139.120.121.1.

However, the next-hop IP address139.120.121.1does not belong to the same subnet as the directly connected interface on R1, which is172.31.1.1/30. For the static route to work properly, the next-hop IP address must be reachable via a directly connected interface, meaning it must be within the same subnet.

Therefore, this mismatch in subnet adjacency is likely causing the failure to reach the destination (139.120.121.2).

During the IP forwarding process, routers use the routing table to determine the next hop based on the destination IP address. The source IP address is not directly involved in the lookup process for forwarding.

The ARP table is used to map IP addresses to MAC addresses, specifically for resolving the MAC address of the next hop (destination MAC address) for forwarding packets within the local network.