🧭 Routing Algorithms
Routing algorithms are essential to determine the best path for data to travel across networks. They fall into two broad categories: Distance-Vector and Link-State.
📌 1. Distance Vector Routing
Each router maintains a table (vector) that holds the best-known distance to every destination.
- Based on Bellman-Ford Algorithm
- Routers exchange vectors with neighbors periodically.
- Simple but slow convergence; prone to count-to-infinity problems.
Example Protocol: RIP (Routing Information Protocol)
🛣 2. Link-State Routing
Each router has a complete view of the network topology and calculates the shortest path using Dijkstra’s Algorithm.
- Routers send Link State Advertisements (LSAs).
- Builds a link-state database and a shortest-path tree.
- Faster convergence and better scalability.
Example Protocol: OSPF (Open Shortest Path First)
🔍 Key Routing Algorithms
🧮 Bellman-Ford Algorithm (Distance Vector)
- Each node maintains a table of distances.
- Repeatedly updates table entries based on neighbor’s info.
- Can handle negative weights, but slow convergence.
📐 Dijkstra’s Algorithm (Link State)
- Calculates shortest paths from a source node.
- Uses a priority queue (min-heap) for efficiency.
- Requires knowledge of the entire network.
📊 Comparison
| Feature | Distance Vector (Bellman-Ford) | Link State (Dijkstra) |
|---|---|---|
| Network Knowledge | Local (neighbors only) | Global (entire network) |
| Convergence Speed | Slow | Fast |
| Scalability | Less scalable | More scalable |
| Algorithm Used | Bellman-Ford | Dijkstra |
| Example Protocol | RIP | OSPF |
💡 Deep Insights
- Routing efficiency is a trade-off between knowledge and overhead.
- Distance Vector is lightweight but less responsive to changes.
- Link-State requires more resources but enables faster and smarter decisions.
🔗 Links
- Previous: Network-Layer Protocols
- Next: Routing Protocols: IGP & EGP