As shown in the figure, what is known about the default routes on R4?

Understanding the Routing Table Entries on R4

0.0.0.0/0 (Default Route)is installedtwicein the routing table.

TheNextHopvalues for the default route:

10.1.24.1 (GigabitEthernet0/0/1)

10.1.34.1 (GigabitEthernet0/0/0)

Cost:Both routes have a metric (Cost) of10, meaning they areequal-cost routes.

Protocol:ISIS-L1 (Intermediate System to Intermediate System - Level 1) confirms these routes are coming fromIS-IS routing.

Flags:D (Dynamic) means these routes were dynamically learned via IS-IS.

Why is Option D Correct?

Since both routeshave the same cost (10), they are consideredequal-costdefault routes.

The routerwill use both routes in a load-sharingfashion.

The answeris NOT A(Four equal-cost routes) because there areonly twodefault routes, not four.

The answeris NOT B(One default route) because there aretwo default routesin the table.

The answeris NOT C(Two default routes with different costs) because both routes havethe same cost (10).

Real-World Application

Equal-Cost Multi-Path (ECMP):The router can performload balancingacross the two equal-cost paths.

Resilience & Redundancy:If one link fails, the other can take over without re-calculating the entire routing table.

✅Reference:Huawei HCIE-Datacom Study Guide – IS-IS Routing & ECMP Load Balancing