Unit 3, Chapter 5 & 14 How do they talk to each other? Copyright ©2005 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved

Data Coding & Data Data Coding & Data Communication FundamentalsCommunication Fundamentals

Unit 3, Chapter 5 & 14How do they talk to each other?

Copyright ©2005 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

Objectives

Describe the importance of the use of binary in machine code.Identify the need for parity checking.Explain the three major types of data compression.Describe the commonly used systems in computing.Identify the five classes of IP addresses and the range of addresses for each class.Convert decimal numbers to binary and vice versa.Determine the default subnet mask used with a given IP address..

Data Coding - Binary

Code = set of symbols with specific (predefined) meaning– Morse Code

Binary = Only 2 states On=1, Off = 0Code Points = Number of possible combinations or values– 20=1, 21=2, 22=4, 23=8, 24=16, 25=32, 26=64, 27=128

Characters– Alphanumeric– Control (Device & Transmission)

Data Coding



Parity Bit – Additional Bit to validate data– Odd, Even– ASCII letter R

• No parity = 1010010• Even Parity = 10100101• Odd Parity = 10100100

Escape characters – character following this has special meaning (form feed, line feed, carriage return)

Specific Codes

American Standard Code for Information Interchange (ASCII)– ANSI Standard– 7 Bit code, 128 unique codes– ITU-T International Telegraph Alphabet 5– Extended ASCII, 8 Bit Code, Foreign Characters

Extended Binary Coded Decimal Interchange Code (EBCDIC)– IBM’s flavor– 8 Bit code, 256 unique characters

Unicode– 16 Bit code, 65,536 characters– Handle most every language on the planet

Data Code Particulars

Code Efficiency – How few bits to define a character – Information bits, used to define character– Noninformation bits, used for other purposes(parity)– Code Efficiency = info bits / total bits– ASCII & EBCDIC = 100% Efficient

Data Compression

Reducing the number of bits to represent a characterSave storage, increase throughput – Winzip, ModemsCharacter Compression– Huffman Coding– Most frequent characters replaced with shorter version– Reduce the number of bits sent by a factor of 2

Run Length Compression– Repetitive groups of characters are replaced with shorter group

Character Stripping– Remove leading and trailing control characters

Principles of Internetworking

TCP/IP packet switching networkVarious network technologies are employed – EthernetSubnetworks – Individual networks that are connected togetherEnd System – Device or computerIntermediate system – – Switches = Layer 2 or Layer 3– Bridge = Layer 2– Routers = Layer 3

Virtual Network – Subnets appear to be one large network

OSI –TCP/IP Models

OSI Model TCP/IP

L7 Application

Application

L6 Presentation

L5 Session

L5 Session

TransportL4 Transport

L3 Network

InternetL2 Data Link

L2 Data link Data link (Network interface)

L1 Physical (Hardware)

TCP/IP Protocol Suite

Layer 1 = Physical Layer– Hardware (NIC)

Layer 2 = Network Interface– Split data into packets (frames) to be sent out– Sends frames and routes to devices on the network– Error detection and control for higher layers

Layer 3 = Internet Layer– IP and IP address are used to transmit data– No corresponding OSI layer

Layer 4 = Transport Layer– Ensures no errors and packets are in the correct order

Layer 5 = Application Layer

Internet Protocol Addressing

IP Address is uniqueIPV4 – 32 Bit Address, 4 Octets (xxx.xxx.xxx.xxx)– Host portion-Host_id (nnn.hhh.hhh.hhh)– Network portion-Network-id (nnn.hhh.hhh.hhh)– 5 Network classes

• Class A, starts with 0, range 0 – 126• Class B, starts with 10, range 128 – 191• Class C, starts with 110, range 192 – 223• Class D, starts with 1110, range 224 – 239 (multicast)• Class E, starts with 1111, range 240 – 255 (reserved)• Private address= 10.0.0.0,192.168.0.0,172.16.0.0

IP Classful Addressing

Address Classes:IP Address Rule I



Address Classes:IP Address Rule II



Address Classes:IP Address Rule III

Cisco Learning InstituteNetwork+ Fundamentals and Certification



Subnets & Subnetting

Subnetwork or Subnet – separate part of an organizations network that is identifiableSecurity and traffic controlSubnet mask – 32 Bit number – ANDed with network portion of address(only 1+1=1)– 1’s = network and 0’s = host– Ex. Class A 255.0.0.0, network info is in the first octet

Default Subnet Masks– Class A = 255.0.0.0– Class B = 255.255.0.0– Class C = 255.255.255.0

Bits in the host octets are used to define subnet(pg 388)– Class C address 206.11.20.81– Subnet mask 255.255.255.224 or /27

• 11111111.11111111.11111111.11100000• 81 = 0101 0001

– Subnet Number 2– Host ID 17

Subnets & Subnetting

Classless Inter-Domain Routing:CIDR Address Prefix and Number of Class C

Addresses




Addressing Particulars

/nn Classless Internet Domain Routing– 204.11.20.16/19 or Subnet mask

11111111.11111111.11100000.00000000

Supernetting – several class C addresses into a contiguous address blockDynamic IP address – address assigned when neededStatic – address is configured and does not change(routers…infrastructure equipment)Private networks – 10.0.0.0, 172.16.0.0,192.168.0.0

Subnetting Example

Step Example Rules

Address 8.1.4.5 None

Mask 255.255.0.0 None

Number of network bits 8 Always defined by Class A,B,C

Number of Host Bits 16Always defined by the number of binary 0s in the

mask

Number of Subnet Bits 8 32 - (Network size + host size)

Total 32 Network + Host + Subnet

Domain Names

Mnemonic for IP address (WWW.MSN.COM)Domain Name Services(DNS) used to translate or resolve name to addressHierarchical Structure– Local– Corporate– Global

Top Level Domain (.com,.edu,.net,.org….)Internet Corporation for Assigned Names and Numbers (ICAAN)Root Servers – Contain IP addresses of all TLD registries

Transmission Control Protocol

Can communicate between hosts with diverse hardware and operating systemsDeveloped by Defense Advanced Research Projects Agency (DARPA)Direct or point-to-point communicationsConnection oriented communicationFull Duplex – communication in both direction3 way hand shake to start communications & End Communications– Start:->SYN,<-SYN+ACK,->ACK – End: ->FIN+ACK,<-FIN+ACK,->ACK

TCP HEADER

TCP Header Information

TCP/IP Header:Stop-and-Go (left) versus Sliding Window Flow Control

(right)



TCP/IP Header:Sliding Window Flow Control in

Operation



User Datagram Protocol

Simple protocolConnectionlessNo error checkingNo sequencingNo HandshakingExamples: Ping, DNS, VOIP, TFTP

UDP Header:UDP Diagram Format




UDP Header:IP Header Field Information




TCP/UDP Port Number:Selected Well-Known Port Numbers




Port TCP UDP Protocol

20 FTP Data21 FTP Control22 SSH (Secure Shell)23 Telnet25 SMTP53 DNS69 TFTP80 HTTP

TCP/UDP Port Number:Selected Well-Known Port Numbers




Other Protocols

Address Resolution Protocol (ARP)Dynamic Host Configuration ProtocolFile Transfer Protocol/Trivial File Transfer ProtocolHypertext Transfer Protocol & Hypertext Transfer Protocol over Secure Sockets Layer or Transfer Layer SecurityPost Office Protocol v3 (POP3) & Internet Message Access Protocol v4 (IMAP4)Simple Mail Transfer Protocol

Internet Tools

Name Server Lookup (nslookup)– Determine IP address of a host system

Whois– Determine name from an IP address

Ping – Troubleshooting tool – Is the node there, is it alive, how much time ….

Traceroute– Determine route packet takes to remote host

PING and Tracert:Example 1
























Review Questions

1. A router can connect any combination of LANs and WANs.a. Trueb. False

Review Questions

2. Which of the following is not an Internet top-level domain name?a. .bizb. .govc. .museumd. .mine

Review Questions

3. A _________ is calculated mathematically as a part of the error-checking process when transmitting and receiving a message.a. Greek characterb. check characterc. real characterd. control character

Review Questions

4. Characters that control the positioning of information on a workstation screen or paper are called ______________.a. page control charactersb. format effector charactersc. device control charactersd. a and b

Review Questions

5. What is the default subnet mask for a Class C network?a. 255.255.255.0b. 255.0.0.0c. 0.0.0.225d. 255.255.255.255

Review Questions

6. Which of the following binary numbers is the equivalent of the decimal number 206?a. 11001100b. 11100110c. 11001110d. 10110110

Review Questions

7. The reason that digital transmission is superior to analog transmission is ___________.a. better data integrityb. higher capacityc. better security and privacyd. all of the above

Review Questions

8. A modem converts ________ to ___________.a. Analog to Digitalb. Digital to Analogc. a and bd. none of the above

Review Questions

9. In HDLC, when a 0 bit is inserted after all strings of five consecutive 1 bits, the term applied is ________.a. zeroingb. bit stuffingc. synchronizingd. string breaking

Review Questions

10. When two stations on a circuit transmit at the same time, ______ occurs.a. an altercationb. a divisionc. pollingd. a collision

Homework

Assignment: Due Next Week– Review:

• Chapter 5, pp. 90-101• Chapter 14, pp. 376-411

– Read:• Chapter 7, pp. 158-182• Chapter 18, pp. 531-538

– Complete:• Assignment 3.1: Chapter 5 Multiple Choice pg 184-186• Assignment 3.2: Subnet Homework• Lab 3.3 Use Visio to Draw OSI Model again, this time

include the function of each layer, and the TCP Suite

Documents

Unit 3, Chapter 5 & 14 How do they talk to each other? Copyright ©2005 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved