Introduction to Networking

1. Introduction to Networking V.T. Raja, PhD James R. Coakley, PhD BA 572 – Advanced Information Systems

2. Outline • 5-layer Network Model A theoretical framework for our day-to-day interactions on the Internet Protocol stack • Network Design and Topology

3. Theoretical Framework: 5-layer network model • Application Layer (Layer-5) • Transport Layer • Network Layer • Data Link Layer • Physical Layer (Layer-1)

4. Five-Layer Network ModelMajor Functions • Application Layer • User interface with application software • Example: web/e-mail address • Transport Layer • Packetizing • Breaking large messages into smaller packets at source • Reassembling packets at final destination • Creates/appends TCP header • Packet # • Source/Destination Port ID

5. Five-Layer Network ModelMajor Functions – cont’d • Network Layer: Addressing and Routing. • Internet Protocol prepares IP header. Contents of IP header include: • Source/Destination IP Address and Routing Information • Addressing • DHCP Server (Dynamic Host Control Protocol Server) • Assigns IP addresses to client machines requesting an IP address • DNS Server (Domain Name Service Server) • Similar to directory assistance – used for finding destination IP addresses. • Routing • Routing tables; Routers (Tracert); Routing Protocols

6. Five-Layer Network ModelMajor Functions – cont’d • Data Link Layer • Media Access Control (Handling message collisions) • Error Detection/Error Correction • Message Delineation (Identifying beginning and ending of packets – since all computer transmissions go out as 0s and 1s over the physical layer) • DL layer appends a DL header and DL Trailer • Physical Layer (Layer-1) • Transmission of data

7. Five-Layer Network ModelProtocols and Addresses • HTTP (Hyper Text Transfer Protocol) • Operates at the Application Layer • Example of an application layer address: www.bus.oregonstate.edu • TCP (Transmission Control Protocol) • Operates at the Transport Layer • Example of a transport layer default port address/port ID: • 80 (Web) • 25 (E-mail)

8. Five-Layer Network ModelProtocols and Addresses – cont’d • IP (Internet Protocol) • Operates at the Network Layer. • Example of an IP address: 128.192.64.224 • Ethernet operates at the data link layer. • Example of a DLL address: 00-B0-D0-B4-54-13

9. Layer 1 - Physical Layer • Wired Media/Wireless Media: Examples • Twisted pair; Coaxial; Fiber Optic Cables • Microwave; Satellites and wireless (cell phones)

10. Some Network Topologies • Physical versus logical topology • Star topology • Mesh topology • Bus topology • Ring topology • Physical versus logical topology

13. Ethernet vs. Token RingLocal Area Network • LAN Protocols • Ethernet: Bus with CSMA/CD • Carrier Sense Multiple Access/Collision Detection • Token Ring • FDDI • Fiber Distributed Data Interface • Token Ring on fiber • Fast Ethernet (100 mbps) • Gigabit Ethernet

16. FDDI

17. FDDI (Continued)

18. Network DesignHow to support full connectivity? Usernode Usernode Usernode Usernode WAN Usernode Usernode Usernode Usernode Usernode Usernode • Design the most economic internetwork between “end-user nodes” and an existingWAN

19. Network DesignFind an economic internetworking solution A direct connection to a WAN backbone node Connection via multiplexers Usernode Usernode Usernode Usernode Usernode Usernode Usernode Usernode Usernode Usernode Usernode Usernode

20. Some Network Design IssuesMajor Cost Components • Acquisition and installation costs of a MUX • Cost of high bandwidth link between MUX and WAN (Internet) • Cost of low bandwidth link between end-user node and MUX

21. Network Design ManagementHow to design a feasible and economical internetwork? • Find an optimal number of MUXs to interconnect all given user nodes to some existing WAN such that ... • All user nodes are connected • User communication requirements are satisfied • Capacity constraints on each MUX is not violated • Total internetworking costs are minimized • Topology issues are considered

22. Example 1

23. Example 2

24. Example 3