Which statement is a disadvantage of Distance Vector routing algorithms?

• A. Limited by hop count, unsuitable for large networks.
• B. They are always faster to converge than link-state.
• C. They require zero memory.
• D. They support VLSM in all versions.

Answer: (B)

Distance Vector routing relies on each router advertising its distance to destinations to its neighbors, often using hop count as the metric. A real drawback of this approach is that convergence can be slow and routing loops can occur while updates propagate through the network. The hop-count metric also limits scalability because it treats all links as equal and ignores factors like link speed, reliability, and subnet size. As networks grow, this makes distance-vector routing less suitable, since it can’t always represent optimal paths or prevent issues like loops without additional mechanisms.

So, describing hop-count as a limiting factor that hampers large networks accurately captures the practical disadvantage of distance-vector routing. In contrast, the claim that these protocols’re always faster to converge than link-state isn’t true—link-state generally converges more quickly. The idea that they require zero memory is false, since routing tables need memory, and the notion that all versions support VLSM is incorrect because some versions do not.