Chapter 5. Data Communication And Internet Technology

Transcription

1 Chapter 5 Data Communication And Internet Technology

2 Purpose Understand the fundamental networking concepts

3 Agenda Network Concepts Communication Protocol TCP/IP-OSI Architecture Network Types LAN WAN Public Switched Data Network Virtual Private Network Network Comparison Internet Domain Name System IP Addressing Schemes Security Discussion and Case Study

4 Network Concepts A collection of computers that communicate with one another over transmission lines Types Local area networks (LANs): connects computers in a single geographic location Wide area networks (WANs): connects computers at different geographic sites Internet: a network of networks

5 Communication Protocol Protocol: a standard means for coordinating an activity between two or more entities Communications protocol: a means for coordinating activity between two or more communicating computers The communication protocol is broken into levels of layers Two machines must agree upon and follow the protocol for exchanging the message

6 TCP/IP-ISO Architecture - I International Organization for Standardization (ISO): Reference Model for Open Systems Interconnection (OSI) Internet Engineering Task Force (IETF): Transmission Control Program/Internet Protocol (TCP/IP) TCP/IP-ISO architecture: five layers

7 TCP/IP-ISO Architecture - II Layer 5 (Application): communication rules between two applications Simple Mail Transfer Protocol (SMTP) for Hypertext Transfer Protocol (HTTP) for processing Web page (sites and users) File Transfer Protocol (FTP) for copying file between computers

8 TCP/IP-ISO Architecture - III Layer 4 (Transport): communication rules between two host computers Transmission Control Program (TCP) Sending functions: break data into segments, add To and From address, and Receiving functions: provide reliability by sending acknowledgement, and translate the format, assemble segments into data

9 TCP/IP-ISO Architecture - IV Layer 3 (Internet): communication rules of routing packets across the Internet Internet Protocol (IP) Functions: package each segment into a packet, place IP data in in the packet, add To/From data

10 TCP/IP-ISO Architecture - V Layer 2 (Data Link): communication rule for transmitting data within a single network Functions: package packets into frames Layer 1 (Physical): communication rule between adjacent device connected by a transmission medium

11 Terminology Architecture: an arrangement of protocol layers with their associated tasks Protocol: set of rule to accomplish the tasks Program: software implementing the protocol Web: sub set of Internet with users and sites to process protocol Internet: communication structure Browser: a program implementing the HTTP of the TCP/IP-OSI architecture (Netscape and Microsoft Internet Explorer)

12 TCP/IP-OSI Application Example

13 Network Types LAN: local area network WAN: wide area network

14 LAN - I A group of computers connected together on a single company site and operated by the company Equipments Network interface card (NIC) or onboard NIC: an unique identifier named MAC (media access control) address Unshielded twisted pair (UTP) cable with RJ45 connecter Optical fiber cable with ST and SC connectors

15 LAN - II IEEE (Institute for Electrical and Electronics Engineers) Protocol: IEEE or Ethernet Hardware characteristics (which wire carries which signals) Package and process message over LAN Operate on Layer 1 and 2 10/100/1000 Ethernet (Mbps) Bits for communications speeds and bytes for memory sizes

16 Local Area Network

17 NIC Interface Card

18 Unshielded Twisted Pair (UTP) Cable

19 Optical Fiber Cable

20 LAN - III Wireless LAN Wireless NIC (WNIC) IEEE g protocol to connect to an access point (AP) and IEEE 802.3

21 Wireless Access Standards

22 Wireless LAN

23 WAN Connects computers located at physically separated sites Internet service provider (ISP) Provide customer a legitimate Internet address. Serve as the gateway to the Internet Communicate between sending computer and Internet Connecting computer and ISP Telephone line DSL (digital subscriber line) Cable TV line

24 WAN - Equipment Modem Convert data between digital and analog Narrowband with speed less than 56 kbps and Broadband with speed over 256 kbps Modem types Dial-Up modem Narrowband Point-to-Point Protocol (PPP) DSL modem Permanent connection and one more line for telephone conversation Asymmetric digital subscriber line (ADSL) for home and small business with slow upload speed with 256 kbps and faster download speed ranging from 256 to 768 kbps Symmetric digital subscriber line (SDSL) for advanced users and larger business with Mbps performance level guarantees Cable modem Permanent connection and one more line for TV 10 Mbps download speed and 256 kbps upload speed

25 Analog vs. Digital Signals

26 Personal Computer (PC) Internet Access

27 WAN - Equipment Access devices Switch (Layer 2) Router (Layer 3) Lease lines from telecommunication company T1 line with Mbps speed T3 line with Mbps speed Optical fiber cable-768 with 40 Gbps Point-to-Point Protocol (PPP)

28 Transmission Line Types, Uses, and Speeds

29 WAN Public Switched Data Network Public switched data network (PSDN) Developed and maintained by a vendor for selling time to other company Shown as a cloud in the map or diagram User must have a leased line connecting to PSDN as point of presence (POP) PSDN types Frame Relay with 56 kbps to 40 Mbps: slower and cost less but simple and easy to support Asynchronous transfer mode (ATM) with 1 to 156 Mbps: faster and cost more but transmitting data and voice Ethernet with 10 to 40 Gpbs

30 Wide Area Network Using PSDN

31 WAN Virtual Private Network Virtual private network (VPN): a private internet as a private point-to-point connection Tunnel: a virtual, private pathway over a public or shared network from the VPN client to the VPN server Encrypted message Remote access

32 Remote Access Using VPN

33 Wide Area Network Using VPN

34 Network Comparison Setup costs Operational costs Lease fees for line and equipment ISP charges Training Maintenance: problem diagnosis, repair, and updating Performance Equipment: lines, switches, routers, and access devices Labor Speed: line and equipment Latency: transmission delay due to congestion Availability: service outages Loss rate: transmission problem Transparency Performance guarantee: availability, error rate, speed, etc. Growth potential Contract commitment period Management time Financial risk Technical risk

35 Summary of LAN and WAN Networks

36 Internet Network address Physical or MAC address in Layer 2 program: permanent and unique Logical or IP address in Layers 3, 4, and 5: not permanent, such as Public IP address used on the Internet to major institutions in blocks assigned by Internet Corporation for Assigned Names and Numbers (ICANN) Private IP address used within private networks and internets DHCP server has Dynamic Host Configuration Protocol (DHCP) to assign a temporary IP address for accessing the Internet Network Address Translation (NAT): The process of changing public IP addresses into private IP addresses, and the reverse

37 Domain Name System Convert user-friendly name into their IP address domain name: any registered, valid name with ICANN resolving the domain name: the process of changing a name into its IP address ICANN has 13 computer as root servers for maintaining a list of IP addresses of servers to resolve each type of TLD in the world Top-level domain (TLD) Non-U.S. is the two letter abbreviation for the country U.S. is the type of organization Uniform resource locator (URL): document s address on the Web Domain name resolvers store the correspondence of domain names and IP address

38 IP Addressing Schemes IPv4 and IPv4 32 bits divided into four groups of 8 bits, and a decimal number represents each group The largest decimal number between the period is 255 (0 255) IPv6 128 bits due to the growth of the Internet Currently both IPv4 and IPv6 are used on the Internet

39 Security Encryption algorithms: DES, 3DES, AES Key Symmetric encryption Asymmetric encryption: public key and private key HTTPS Secure Socket Layer (SSL) and Transport Layer Security (TLS) Public key, private key and symmetric encryption

40 Summary TCP/IP-OSI five layers Application layer Transport layer Internet layer Data link layer Physical layer Public switched data network (PSDN) Dynamic Host Configuration Protocol (DHCP) to assign a temporary IP address for accessing the Internet Domain name

41 Discussion Problem solving (121a-b) What are the new opportunities for the business generated by the Internet? What are the new threats for the business generated by the Internet? Opposing forces (129a-b) State your opinions related to the negative impact on the society when everyone is connect through the Internet. Security (133a-b) State the impacts on the society and business from the government having an decryption method to decode everything over the Internet. Ethics (141a-b) State the impacts from the employee s private usage of company s computer facility. Reflections (143a-b) How should you react properly from not getting lost from this Internet age?

42 Case Study Case 5-1 ( ) Network Services: questions 1, 3, 4, 5, 6, 9, and 10

43 Points to Remember Network Concepts Communication Protocol TCP/IP-OSI Architecture Network Types LAN WAN Public Switched Data Network Virtual Private Network Network Comparison Internet Domain Name System IP Addressing Schemes Security Discussion and Case Study