Dynamic Routing Protocols
Routing protocols automate the exchange of network paths between routers. They are essential for scalability, redundancy, and rapid convergence.
OSPF
The industry standard IGP. Uses Link-State logic, Areas, and Dijkstra's Algorithm to build a loop-free topology.
Deep Dive →BGP
The protocol of the Internet. A Path Vector protocol designed for policy control, scaling to 1M+ routes.
Deep Dive →EIGRP
Cisco's advanced hybrid protocol. Famous for the DUAL algorithm and Feasible Successors (sub-second convergence).
Deep Dive →RIP
The original Distance Vector protocol. Simple, useful for small edge cases, but limited by hop count and slow timers.
Deep Dive →IS-IS
The Service Provider's choice. A highly extensible Link-State protocol that runs directly over Layer 2 (Protocol Agnostic).
Deep Dive →Protocol Comparison Cheat Sheet
| Feature | RIPv2 | EIGRP | OSPF | IS-IS | BGP |
|---|---|---|---|---|---|
| Type | Distance Vector | Hybrid (Adv. DV) | Link State | Link State | Path Vector |
| Metric | Hop Count | Bandwidth + Delay | Cost (Bandwidth) | Cost (Arbitrary) | Attributes (Path, LocalPref) |
| Admin Distance | 120 | 90 (Internal) | 110 | 115 | 20 (eBGP) / 200 (iBGP) |
| Convergence | Slow | Fastest (FS) | Fast | Fast | Slow (Stable) |
| Transport | UDP 520 | IP 88 (RTP) | IP 89 | CLNS (L2) | TCP 179 |