BA 370 Telecommunications and Networking Dr V T Raja Oregon State University Raja bus oregonstate edu Outline Introduction Analogy with effective human communication 5 layer Network Model A theoretical framework for better understanding the Internet Introduction to Telecommunication Systems Some Basic Characteristics of Effective Human Communication Sender Receiver Messages Words Transmission Media Air Printed Page Speak same language or have an Interpreter Less noisy room or talk loud enough Some Basic Characteristics of Telecommunication Systems Network Design How to support full connectivity Design the most economic internetwork between end user nodes and an existing WAN Usernode Usernode Usernode Usernode Usernode Usernode Usernode Usernode Usernode WAN Usernode Network Design Find an economic internetworking solution A direct connection to a WAN backbone node Usernode Connection via multiplexers Usernode Usernode Usernode Usernode Usernode Usernode Usernode Usernode Usernode Usernode Usernode Example 1 Example 2 Example 3 Theoretical Framework 5 layer network model Application Layer Layer 5 Transport Layer Network Layer Data Link Layer Physical Layer Layer 1 Protocols and addresses used at different layers of the 5 layer network model 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 Protocols and addresses used at different layers of the 5 layer network model 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 B454 13 In wired media twisted pair coaxial and fiber optic cables form the physical layer Application and Transport Layers User interfaces with application software using Application layer e g web e mail address Transport layer s major function is Packetizing Breaking large messages into smaller packets at source Reassembling packets at final destination Creates appends TCP header Packet Source Destination Port ID Layer 3 Network Layer Major functions of IP at network layer are Addressing and Routing Internet Protocol prepares IP header Contents of IP header include Source Destination IP Address and Routing Information Network Layer Continued 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 Layer 2 Data Link Layer Major functions of Data Link Layer are 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 Layer 1 Physical Layer Wired Media Wireless Media Examples Twisted pair Coaxial Fiber Optic Cables Microwave Satellites and Cell phones Internetworking Devices Examples Hubs Multiplexers DSL Cable Modems Switches Routers