1. Spring 20031 Ch 17 Internetworking Concepts, Architecture, and Protocols Part III Internetworking

2. 2 Motivation For Internetworking  LANs Low cost Limited distance  WANs High cost Unlimited distance  A heterogeneous world No single networking technology is best for all needs

3. 3 Heterogeneity and Universal Service  Incompatibilities among networks Electrical properties Signaling and data encoding Packet formats Addresses EthernetFDDI

4. 4 Internetworking  Connect a set of physical networks by router A router can interconnect networks that use different technologies, including different media and media access techniques, physical addressing schemes, or frame formats

5. 5 A Virtual Network IP addresses MAC addresses

6. 6 To Hide Heterogeneity  Create “virtual” network  Invent Addressing scheme (IP addresses) Naming scheme  Implement with Protocol software  Note: protocol software needed on both hosts and routers

7. 7 TCP/IP Layering Model

8. 8  Layer 1: Physical Basic network hardware  Layer 2: Network interface MAC frame format MAC addressing Interface between computer and network (NIC)  Layer 3: Internet Facilities to send packets across internet composed of multiple routers TCP/IP Layering Model

9. 9  Layer 4: Transport Transport from an application on one computer to application on another  Layer 5: Application Everything else (i.e., layers 5-7 in OSI model) TCP/IP Layering Model