Introduction to Management Information Systems Chapter 5 Data Communications and Internet Technology HTM 304 Fall 07

2 Content 1.5-layer Architecture for Communication 2.Internet 3.Enterprise Network 4.Wireless

3 Last Time: The 5-Layer Model Hardware Layer: Set the devices ready for communication.

4 Layer 3: Internet Layer Runs the IP protocol Data received from the above layers are divided into packets. Key design issue – to determine how packets are routed from source to destination. Routing: selecting paths – shorter route, avoiding heavy traffic, etc. Router: special-purpose computing devices that process IP protocol – examine the destination IP addresses and decide where to send them.

5 IP Address (IPv4) Layer 3 handles IP address. The Logical Addresses Assigned when you get online, not permanently tied with the MAC address Why? Don’t have to update every time a NIC is changed An IP address is four bytes, totally 32 bits. How many in total? You can either specify your IP address (as most of the company’s server), or let the ISP assign one dynamically.

6 IPv6 Windows Vista has adopted IPv6. Totally 128 bits (=16 bytes) instead of 32 bits (=4 bytes) How many total IPv6 addresses?  3.4 * addresses Approximately 5 * addresses * 6.5 billion people alive today. Example of address: (8 Hexadecimal digits) 2001:0db8:85a3:08d3:1319:8a2e:0370:7334

7 Exercise: Find your IP address How to find your IP address? “start”  “run”: type “cmd” and click ok, the command prompt window will pop up Type command “ipconfig” to observe the report Use “ping” command to check the connectivity between two computers

8 Router – 3 rd Layer Equipment Application Layer Transport Layer Internet Layer Data Link Layer Physical Layer Computer A Application Layer Transport Layer Internet Layer Data Link Layer Physical Layer Internet Layer Data Link Layer Physical Layer Computer B Router A (can actually many) Packets: Original IP – source IP + Data Frames: Original MAC – Next MAC + Packets Data Link

9 Explain: Why Router? – handle address Can be substituted by a computer with routing Programs installed. Multiple NICs needed.

10 Layer 4 Transport Layer Handles transport protocol: TCP or UDP – software protocols Application Layer Transport Layer Internet Layer Data Link Layer Physical Layer Computer A Application Layer Transport Layer Internet Layer Data Link Layer Physical Layer Internet Layer Data Link Layer Physical Layer Computer B Router A (can actually many) Data Link Once paths from computer A to B is found, an end-to-end connection is established on the 4 th layer. Meaning data can be transferred. Point-to-point

11 Layer 4 Protocols TCP: Transmission Control Protocol Receive data and transmission request from Layer 5 (application layer) Send communication request to layer 3, layer 3 will then find one or more route to the destination computer. Destination computer send acknowledge back, indicating there is end-to- end connection. Break data from layer 5 into segments, and send each segments with confirmation. (destination computer send acknowledge upon receiving every segment) UDP: User Datagram Protocol Designed for short messages Does almost everything the same as the TCP, except not requesting confirmation. Faster, more efficient for short messages and time-sensitive application

12 Layer 5 The Application Layer Layer 5 protocols for applications such as browsers, , file transfer, etc. A standard protocol Simple Mail Transfer (SMTP) Web page processing Hypertext Transfer Protocol (HTTP) File Transfer Protocol (FTP) It governs how applications work with each other. (e.g. Firefox v.s. IE 7)

13 Review of the 5 layers See your handout

14 Review the Data Process

15 Exercise Which of the following is referred to as the network cable? Coaxial Cable Fiber Optic Cable Unshielded Twisted Pair Twisted Pair Copper

16 More exercise? What is the name of data unit transferred on the 2nd layer? Packet Bytes Package Frame Segment

17 Explain IEEE 802? Which of the following standard in IEEE 802 is referred to as Ethernet? IEEE IEEE IEEE IEEE 802.5

18 Describe the three topologies mainly used to connect a LAN. Describe the pros and cons. Which one can be extended to a large geographic area Which topology corresponds to the Ethernet? Describe the difference between an “end-to-end” connection and a “point-to-point” connection?

19 Multiple Choices __________ contains the destination computer’s IP address in its header. A frame A segment A packet An message