Overview
Distance vector protocols operate on the principle of 'routing by rumor.' Each router shares its entire routing table with its direct neighbors at regular intervals. Routers do not have a complete map of the network; they only know the distance and the next-hop interface to reach a destination.
Key Characteristics
- Metric: Often uses hop count (e.g., RIP).
- Updates: Periodic broadcasts or multicasts of the entire routing table.
- Convergence: Generally slower than link-state protocols.
Common Issues
- Routing Loops: Can occur if not properly managed (mitigated by split horizon, poison reverse, and hold-down timers).
- Count to Infinity: A problem where routers keep incrementing the hop count for an unreachable network.