What is a characteristic of Distance Vector routing in terms of how updates are propagated?

• A. Updates are propagated by broadcast and rely on neighbor's tables.
• B. Updates occur only on changes and require full topological mapping.
• C. They rely on a central routing server.
• D. They do not exchange routing information with neighbors.

Answer: (B)

Distance Vector routing learns about network routes by sharing each router’s distance to destinations with its directly connected neighbors. Updates are sent to those neighbors, typically on a regular timer, and they can also be sent when a topology change occurs. Each router then uses the received vectors to update its own routing table, choosing the best next hop based on the lowest distance. Unlike approaches that require a complete, global map of the network, Distance Vector doesn’t maintain a full topological view; it relies on information from neighbors to build its table. There is no centralized routing server in this model.