Introduction

• The Distance Vector (DV) routing algorithm is a iterative, asynchronous, and distributed approach for computing shortest paths in a network.
• Each node maintains a distance vector, which estimates the cost to all other nodes in the network.
• Nodes exchange their distance vectors with neighbors to update and optimize routing paths dynamically.

Routing Information Maintained by Each Node

• Neighbor Costs: Each node knows the cost to directly connected neighbors.
• Distance Vector: A table containing cost estimates to all destinations in the network.

Distance Vector Update Process

• Each node periodically sends its distance vector to its directly connected neighbors.
• When a node receives a new distance vector from a neighbor, it updates its own vector using the Bellman-Ford equation:D_x(y) = min_v {c(x, v) + D_v(y)}where:
  • Dₓ(y): Cost from node x to destination y
  • c(x, v): Cost to a directly connected neighbor v
  • Dᵥ(y): Neighbor v's cost to destination y
• If a node's distance vector changes after an update, it propagates the updated vector to its neighbors.

Characteristics of Distance Vector Routing

• Distributed and Asynchronous: Nodes update independently without centralized control.
• Iterative Process: Updates continue until all nodes have the best possible routes.
• Slow Convergence: The algorithm may take time to stabilize after network topology changes.

Reference Books

1. Kurose, J. F., & Ross, K. W. Computer Networking: A Top-Down Approach. Pearson.
2. Tanenbaum, A. S., & Wetherall, D. J. Computer Networks. Pearson.