1. COMPUTER NETWORKS
CS610
Lecture-40
Hammad Khalid Khan

2. Review Lecture 39 IP Routing (Ch. 27)
Static Routing Vs. Dynamic Routing
Static Routing in Hosts and a Default Route
Dynamic Routing and Routers

3. Routing in the Global Internet

4. Autonomous System Concept
Set of networks and routers under one administrative authority
Flexible, soft definition
Intuition: a single corporation
Needed because no routing protocol can scale to entire Internet
Each AS chooses a routing protocol

5. Classification of Internet Routing Protocols
Two broad classes:
Interior Gateway Protocols (IGPs)
Used among routers within an autonomous system
Destinations lie within IGP
Exterior Gateway Protocols (EGPs)
Used among autonomous systems
Destinations lie throughout Internet

6. Illustration of IGP / EGP Use

7. Routes and Data Traffic
Each ISP is an autonomous system that uses an Exterior Gateway Protocol to advertise its customers’ networks to other ISPs
After an ISP advertises destination D, datagrams destined for D can begin to arrive

8. Summary Routing in The Global Internet Autonomous System Concept
Classification of Internet Routing Protocols
Optimal Routes