Quản lý mạng cơ bản: Bài giảng chương 7

Chapter 7: TCP/IP

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Objective

 Converting

• Decimal to binary ( binary to decimal) • Decimal to hexadecimal (hexadecimal to decimal) • Binary to hexadecimal (hexadecimal to binary)

 Understanding TCP/IP

• IP address and Subnetting

 Protocol for TCP/IP

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The Binary System

 Computing devices communicate with 1s

and 0s

 A groups of 8 bits = 1 byte  Binary numbers are based on the powers of 2 because there are only 2 symbols: 0 and 1

 Binary can be converted to decimal in a similar

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way that decimal numbers are figured

The Binary System (2)

 Binary can be converted to decimal in a similar

 Example: 1010

way that decimal numbers are figured

= (1x23)+(0x22)+(1x21)+(0x20)

= (1x8)+(0x4)+(1x2)+(0x1)

= 8 + 0 + 2 + 0

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1010 = 10

The Decimal System

 Humans use the decimal number system base on

 10 symbols are used: 0,1,2,3,4,5,6,7,8,9 

the powers of 10

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In a decimal number, each symbol represents 10 raised to a power according to its position that is then multiplied by that position

The Decimal System (2)

 Example:

261 = (2 x 102) + (6 x 101) + (1 x 100)

(2 x 100) + (6 x 10) + (1 x 1)

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261 = 200 + 60 + 1

The Decimal System (3)

 Converting decimal to binary:

• Example: 49

– 49/2 = 24 with a remainder of 1 – 24/2 = 12 with a remainder of 0 – 12/2 = 6 with a remainder of 0 – 6/2 = 3 with a remainder of 0 – 3/2 = 1 with a remainder of 1 – 1/2 = 0 with a remainder of 1 – 49 = 110001

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The Hexadecimal System

 A hexadecimal system based on power of the

 16 symbols are used:

number 16

 Example:

0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F

7FA2 = (7x163) + (Fx162) + (Ax161) + (2x160)

7FA2 = 28672 + 3840 + 160 + 2

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7FA2 = 32674

The Hexadecimal System (2)

 Converting decimal to hexadecimal:

• Example: 127

– 127/16 = 7 with a remainder of 15 (F) – 127 = 7F

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The Hexadecimal System (3)

 Converting hexadecimal to binary by divide

Binary Dec Hexa 0000 0 0001 1 0010 2 0011 3 0100 4

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binary to 4 bit groups:

The Hexadecimal System (4)

Binary Dec Hexa 0101 5 0110 6 0111 7 1000 8 1001 9

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The Hexadecimal System (5)

Binary Dec Hexa 1010 10 1011 11 1100 12 1101 13 1110 14 1111 15

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The Hexadecimal System (6)

 Example:

1101 1010 0100 0110 = DA46

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C9F7 = 1100 1001 1111 0111

IP Addresses

 An IP (Internet Protocol) address is a unique identifier

for a node or host connection on an IP network.  An IP address is a 32 bit binary number usually

represented as 4 decimal values, each representing 8 bits

 Range 0 to 255 (known as octets) separated by decimal

points

 Example: 140.179.220.200

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Introducing IP Addresses

• Unique addressing allows communication

between end stations.

• Path choice is based on destination address. Location is represented by an address

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IP Addressing

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IP Addresses (2)

 Every IP address consists of two parts

• One identifying the Net ID (network identifier) • One identifying the Host ID (host identifier)

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Host Addresses

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Network ID and Host IDs

 A Network ID is assigned to an organization by

 Host IDs are assigned locally by a system

a global authority

 Both the Network ID and the Host ID are used

administrator

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for routing

IP Address Classes

ClassClass AA

HostID HostID 00 NetID NetID

1010 NetID NetID HostID HostID

BB

110110 HostID HostID NetID NetID

CC

1110 Multicast Address Multicast Address

DD

8 bits

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IP Address Classes

 Class A:

• 126 possible network ID • 16.777.214 host IDs per network ID • addresses begin with 0xxx, or 1 to 126 decimal

 Class B:

• 16384 possible network IDs • 65.534 host IDs per network ID • addresses begin with 10xx, or 128 to 191 decimal

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IP Address Classes (2)

 Class C:

• 2 million possible network IDs(2.097.152) • about 254 host IDs per network ID • addresses begin with 110x, or 192 to 223 decimal

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Special Addresses

 Addresses beginning with 01111111, or 127 decimal, are reserved for loopback and for internal testing on a local machine ( ping 127.0.0.1)

 10.0.0.0 – 10.255.255.255, 172.16.0.0 –

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172.31.255.255, 192.168.0.0 – 192.168.255.255: unused Internet address

Host and Network Addresses

 A single network interface is assigned a single IP

 A host may have multiple interfaces, and

address called the host address

 Hosts that share a network all have the same IP

therefore multiple host addresses

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network address (the network ID)



Host and Network Addresses (2)

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In the example, 140.179.220.200 is a Class B address so by default the Network part of the address (also known as the Network Address) is defined by the first two octets (140.179.x.x) and the Host part is defined by the last 2 octets (x.x.220.200)

IP Broadcast and Network Addresses

 An IP broadcast addresses ( that is send to all hosts on the network) has a host ID of all 1s  An IP address that has a host ID of all 0s is

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called a network address and refers to an entire network

Subnet Mask

 Default subnet masks: • Class A : 255.0.0.0

(11111111.00000000.00000000.00000000)

• Class B : 255.255.0.0

(11111111.11111111.00000000.00000000)

• Class C : 255.255.255.0

(11111111.11111111.11111111.00000000)

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Subnet Mask (2)

 Applying a subnet mask to an IP address to

 Performing a bitwise logical AND operation between the IP address and the subnet mask results in the Network Address ( also call Network Number)

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identify the NetID and HostID • The network bits are presented by the 1s in the mask • The host bits are presented by the 0s

Subnet Mask (3)

 For example:

• 10001100.10110011.11110000.11001000

(140.179.240.200 Class B IP Address) • 11111111.11111111.00000000.00000000 (255.255.000.000 Default Class B Subnet) • mask • 10001100.10110011.00000000.00000000

(140.179.000.000 Network Address)

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Addressing Without Subnets

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Subnet Addressing

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Subnet Addresses

 An organization can subdivide it’s host address

 To create subnet address, administrator borrows

space into groups called subnets

some bits from host field

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1010 NetID NetID HostID SubnetID HostID SubnetID

Subnet Mask

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 Subnets not in use—the default

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Subnet Mask Without Subnets

 Network number extended by eight bits

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Subnet Mask with Subnets

 Network number extended by ten bits

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Subnet Mask with Subnets

An Example

 You are assigned a Class C network number of 200.133.175.0 (apologies to anyone who may actually own this domain address). You want to utilize this network across multiple small groups within an organization. You can do this by subnetting that network with a subnet address

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An Example (2)

 We will break this network into 14 subnets of 14 nodes each. This will limit us to 196 nodes on the network instead of the 254 we would have without subnetting, but gives us the advantages of traffic isolation and security. To accomplish this, we need to use a subnet mask 4 bits long

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An Example (3)

 Recall that the default Class C subnet mask is  255.255.255.0

 Extending this by 4 bits yields a mask of  255.255.255.240

(11111111.11111111.11111111.00000000 binary)

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(11111111.11111111.11111111.11110000 binary)

An Example (4)

This gives us 16 possible network numbers, 2 of which cannot be used:

Subnet bits

Host Addresses

Network Number

Broadcast Address

0000

200.133.175.0

Reserved

None

0001

200.133.175.16

.17 thru .30

200.133.175.31

0010

200.133.175.32

.33 thru .46

200.133.175.47

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An Example (5)

Subnet bits

Host Addresses

Network Number

Broadcast Address

….

…..

1101

209 thru .222

200.133.175.20 8

200.133.175.22 3

1110

225 thru .238

200.133.175.22 4

200.133.175.23 9

1111

Reserved

None

200.133.175.24 0

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Protocol

 Protocols are the rules and procedures for

communicating

 Three points to think about protocols

• Many protocols, each has it sown advantages and restrictions • Protocols work at various OSI layers, the layer in which it works

describes its function

• Several may work together in a protocol stack or suite: Levels in protocol stack map or correspond to the layers of the OSI model

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TCP/IP

 Transmission Control Protocol/ Internet

 Provides routable, enterprise networking

Protocol

 Access to worldwide internet  Protocols written for TCP/IP:

• SMTP , FTP, SNMP

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protocol

TCP/IP (2)

 The function of the TCP/IP protocol stack, or suite, is the transfer of information from one network device to another. In doing so, it closely maps the OSI reference model in the lower layers, and supports all standard physical and data link protocols

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TCP/IP (3)

 DNS (Domain Name System) is a system used in the Internet for translating names of domains and their publicly advertised network nodes into addresses

 WINS (Windows Internet Naming Service) is a Microsoftdeveloped standard for Microsoft Windows NT that automatically associates NT workstations with Internet domain names

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TCP/IP (4)

 POP3 (Post Office Protocol) is an Internet

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standard for storing email on a mail server until you can access it and download it to your computer. It allows users to receive mail from their inboxes using various levels of security

TCP/IP (5)

 SMTP (Simple Mail Transport Protocol) governs

 SNMP (Simple Network Management Protocol) is a protocol that provides a means to monitor and control network devices, and to manage configurations, statistics collection, performance and security

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the transmission of email over computer networks. It does not provide support for transmission of data other than plain text

TCP/IP (6)

 FTP (File Transfer Protocol) is a reliable

 HTTP (Hypertext Transfer Protocol) is the

connectionoriented service that uses TCP to transfer files between systems that support FTP

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Internet standard that supports the exchange of information on the World Wide Web, as well as on internal networks. It supports many different file types, including text, graphic, sound, and video

TCP/IP (7)

 Telnet is a standard terminal emulation protocol

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used by clients for the purpose of making remote terminal connections to Telnet server services; enables users to remotely connect to routers to enter configuration commands