Distance Vector Routing (Bellman-Ford)

💡 The Core Idea

In Distance Vector routing, nodes iteratively calculate the shortest path using the Bellman-Ford equation. It is distributed and asynchronous; nodes do not need a global map, they simply trust their neighbors’ estimates.

🧠 The Equation

$D_x(y) = min_v \{c(x,v) + D_v(y)\}$

• $D_x(y)$: Cost from node $x$ to destination $y$.
• $c(x,v)$: Cost to neighbor $v$.
• $D_v(y)$: The neighbor $v$‘s current cost to reach $y$.

⚙️ How it works

1. Wait: Wait for a change in local link cost or a message from a neighbor.
2. Recompute: Run the Bellman-Ford equation using the new data.
3. Notify: If the least-cost path changes, send the new distance vector to neighbors.

🔗 Connections

• Source: Source - Intradomain Routing
• Protocol Implementation: Concept - RIP Protocol (Not explicitly extracted but mentioned in source as RIP)