4A0-112 Nokia IS-IS Routing Protocol Questions and Answers

Route redistributionis the process of sharing routing information between different routing protocols or routing domains. For example, a router might redistribute routes learned via OSPF into a BGP routing table or vice versa. This enables routers to exchange routing information even when they are using different routing protocols.

In both broadcast and point-to-point interfaces, IS-IS routers identify neighbors using system IDs, not interface MAC addresses. The system ID is a unique identifier assigned to each router, and it is used to identify neighbors in both types of interfaces.

In IS-IS, routers are actually associated withinterfacesrather than the entire router being associated with a single area. A router can have interfaces in multiple areas, and it is the interface's configuration that determines which area it belongs to.

In IPv6, the Neighbor Discovery Protocol (NDP) replaces the Address Resolution Protocol (ARP) used in IPv4. NDP is responsible for several functions, including resolving IP addresses to MAC addresses (similar to ARP), detecting duplicate IP addresses, and discovering other devices on the network.

In IPv6, consecutive sections of zeros can be abbreviated with a double colon (::) once in an address. Also, leading zeros in each hextet (group of four hexadecimal digits) can be removed.

The original address is2001:0da8:0000:0000:0024:0000:4ab9:0300.

Removing leading zeros and applying the abbreviation:

0da8becomesda8.

0000becomes0(and multiple consecutive 0000 sections can be represented by ::).

The final result becomes2001:da8::24:0:4ab9:300, which matches option A when properly formatted.

In IS-IS, the Designated Intermediate System (DIS) is responsible for certain tasks on broadcast networks, such as generating link-state advertisements and acting as the central point for flooding information.

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).

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.