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Introduction to Dynamic Routing Protocols (IGP vs EGP)

CCNA: 0 to Hero - Comprehensive Network Engineering Bootcamp

Lesson 37: Introduction to Dynamic Routing Protocols

Dynamic routing protocols automate the process of route learning and path selection, essential for large networks.

IGP vs. EGP

  1. Interior Gateway Protocols (IGP): Used for routing within an Autonomous System (AS)—a single organization or control domain. Examples: OSPF, EIGRP, RIP.
  2. Exterior Gateway Protocols (EGP): Used for routing between different Autonomous Systems. The dominant EGP is BGP (Border Gateway Protocol) (beyond CCNA scope, but good to know).

Classifications by Algorithm

  1. Distance-Vector Protocols (e.g., RIP): Routers share their entire routing table with neighbors. They rely on the neighbor's perspective ('routing by rumor').
  2. Link-State Protocols (e.g., OSPF): Routers share detailed information about their local links and status. Each router builds a complete topology map (SPF tree) of the entire network.
  3. Advanced Distance-Vector/Hybrid (e.g., EIGRP): Uses characteristics of both types for faster convergence and better scaling.