CST 311 Week 6

 Networking Episode II: The Router Strikes Back

This week in CST 311 was the highly anticipated sequel to the study of the Network Layer, focusing on the control plane. We examined routing algorithms and their impact on data flow, exploring two paradigms of network control: the per-router control plane and the logically centralized control plane, along with their implications for routing and management.

LAN Solo or Darth VLAN

The per-router control plane relies on individual routers communicating to determine optimal paths. We studied routing algorithms such as Link-State (OSPF) and Distance Vector (BGP) protocols. Link-State protocols provide a complete network view for informed routing decisions, while Distance Vector protocols optimize routes through iterative information exchange with neighbors.

The logically centralized control plane, foundational to Software Defined Networking (SDN), uses a centralized controller to compute forwarding tables, simplifying network management and improving efficiency by reducing router misconfigurations.

Return of the Nedi - Network Delimiter Algorithm's

We revisited Dijkstra's Algorithm and the Bellman-Ford Algorithm, which represent the core methodologies of Link-State and Distance Vector routing, respectively. Dijkstra's algorithm finds the shortest path by minimizing aggregate cost, while Bellman-Ford employs distributed computations to update distance vectors. Understanding these algorithms clarified when to use each protocol based on network requirements.

We also examined limitations such as routing loops and the count-to-infinity problem in Distance Vector routing. Techniques like poisoned reverse help mitigate these issues but underscore the challenges of distributed routing.

SDN - The Phantom Network

SDN separates the control plane from the data plane, using a centralized controller to make routing decisions. This enables sophisticated routing and enhanced network management by decoupling infrastructure from decision-making logic. As networks grow, SDN provides the flexibility needed for advanced traffic engineering.

May the Ports be With You

That wraps up the network layer; next week, we shift to the Link Layer in the top-down approach to Networking.