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

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.

In this scenario, the routers are configured with an Equal-Cost Multi-Path (ECMP) value of 4, meaning they can utilize up to 4 equal-cost paths to reach a destination. Since Router R5 is advertising the 192.168.3.0/24 prefix and all links have the same cost, router R3 will receive multiple routes to reach this destination.

Given that all the routers (R1, R2, R3, R4, and R5) are connected in a way that can support multiple equal-cost paths, and assuming ECMP is set to 4, the routing table on Router R3 will have up to 4 entries for the prefix 192.168.3.0/24.

Thus, Router R3's routing table will contain4 entriesfor the prefix 192.168.3.0/24.

When a router receives a CSNP (Complete Sequence Number PDU) that references an older LSP (Link-State PDU) than the one in its local database, it indicates that the neighbor is missing newer information.

In response, the router sends back a PSNP (Partial Sequence Number PDU) to the neighbor, which includes a copy of the LSPs it has in its local database that the neighbor may not yet have. This helps to synchronize the link-state information between routers.