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

From the route tables ofR3andR4, we can see thatremote routesare present, withR3andR4both having routes referencing routers in different areas (Area 49.01 and 49.02). These remote routes are characteristic ofroute leaking, which is the process of sharing routes between different IS-IS areas.

R3has routes forR1,R2, andR4, which are in Area 49.01, suggesting thatR1 and R2have advertised their routes toR3, possibly due toroute leaking.

R4has similar routes forR2andR3, indicating thatR2might have advertised its routes toR4.

This sharing of routes between areas is indicative ofroute leakingbeing configured on bothR1andR2, allowing these routes to be shared across the areas.

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.

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.