internetworking fundamentals(networking)
Post on 28-Jan-2015
124 Views
Preview:
DESCRIPTION
TRANSCRIPT
1
Module 1
Introduction to Internetworking
By Dr. Percy DIAS
© 2009, Cisco Systems, Inc. All rights reserved.
2
Computing Measurement Terms
• Bits are binary digits. They are either 0s or 1s. In a computer, they are represented by On/Off switches or the presence or absence of electrical charges, light pulses, or radio waves.
3
Computing Measurement Terms
4
Base 10 (Decimal) Number System
5
Base 10 (Decimal) Calculations
• Should be familiar because you’ve used it since childhood• Example: the number 235 = (2 x 100) + (3 x 10) + (5 x 1)• Because you’ve used it so long, you probably don’t think
about it
6
Base 2 (Binary) Numbers
7
Base 2 (Binary) Numbers
• Binary uses just two digits, 0 and 1• Similar to Base 10; differences are in the details• Example: the binary number 11101011 is equivalent to the
decimal number 235 – Add the decimal value of each bit to get the decimal number
• (1 * 128) + (1 * 64) + (1 * 32) + (0 * 16) + (1 * 8) + (0 * 4) + (1 * 2) + (1 * 1) = 235 decimal
1
8
Four-Octet Dotted-decimal Representation of 32-Bit Binary
Numbers• Split the binary number into four groups of eight
binary digits. Then convert each group of eight bits, also known as an octet into its decimal equivalent.
9
Converting IP Addresses Between Decimal and Binary
• IP addresses are 32-bit binary numbers• Humans find it easier to read decimal
numbers, so IP addresses are often expressed in dotted-decimal format
• Each decimal number represents 8 binary digits, also know as an “octet”
• Each octet can be converted to a decimal number between 0 and 255, inclusive
10
Converting Decimal to Binary
Start by dividing the decimal by the largest number in the Value row that will go.
11
Converting 8-bit Binary Numbers to Decimal Numbers
12
Converting 8-Bit Binary to Decimal
• Binary numbers are converted to decimal numbers by multiplying the binary digits by the base number of the system, which is base 2, and raised to the exponent of its position.
13
Hexadecimal• The base 16, or hexadecimal (hex), number
system is used frequently when working with computers, because it can be used to represent binary numbers in a more readable form.
14
Hexadecimal
• Popularly called “hex”
• Each hex digit represents 4 bits
• Uses 16 symbols: 0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F
• A = 10, B = 11, C = 12, D = 13, E = 14, F = 15
15
Conversion
16
Boolean or Binary Logic• Boolean logic is based on digital circuitry
that accepts one or two incoming voltages. • Boolean logic is a binary logic that allows
two numbers to be compared and generate a choice based on the two numbers.
17
Boolean or Binary Logic
18
Network Protocols
• Communication must follow a set of rules• Networking rules are defined by a set of
standards and protocols• A single standard or protocol defines what a
small part of the network does• The Transmission Control Protocol/Internet
Protocol (TCP/IP) suite defines a large set of standards and protocols used to network computers
19
Media
• Media refers to the various physical environments through which transmission signals pass.
• Common network media include twisted-pair, coaxial, fiber-optic cable, and the atmosphere through which wireless transmission occurs.
Network Media
Media Example Encoding
Copper Twisted-pair cable usually used as LAN media
Electrical pulses
Fiber-optic Glass or plastic fibers in a vinyl coating usually used for long runs in a LAN as a trunk
Light pulses
Wireless Connects local users through the air
Electromagnetic waves
20
Network Media
21
22
Local-area Networks (LANs)
LAN Technology: Ethernet, Token Ring, FDDI (Fiber Distributed Data Interface)
23
Wide-area Networks (WANs)
Internetworks Made Up of LANs and WANs
24
25
Importance of Bandwidth
• Bandwidth is defined as the amount of information that can flow through a network connection in a given period of time
26
Bandwidth Pipe Analogy
27
Bandwidth Highway Analogy
28
The Need for Networking Protocols and Standards
• 1960s to 1980s – Each vendor set its own proprietary protocols and standards
• Equipment from different vendors would not interoperate
• Eventually, open standards were agreed upon
• Open standards allow more competition, which increases speed of development
29
Using Layers to Describe Data Communication
• Data communication is a very complex process.• Difficult to understand this process as a whole.• Solution is to break down the total network
communication system into a series of layers.• Each layer is responsible for a specific part of
network communication.• These layers interact with the layer above and
below.• Two common network models that use layers
are Open System Interconnection (OSI) reference model and the TCP/IP reference model.
30
OSI Reference Model
31
Functions of Layer 7
• Application Layer: Network Process to Applications – Provides network services to the user’s
application– User interface– Examples – Telnet, HTTP, Web browsers
32
Functions of Layer 6
• Presentation Layer: Data Representation–Ensures that the information that the application
layer of one system sends out is readable by the application layer of another system
–How data is presented–Special processing, such as data format,
compression and encryption
33
Functions of Layer 5
• Session Layer: Interhost Communication–Establishes, manages, and
terminates session between two communication host.
34
Functions of Layer 4
• Transport Layer: End-to-End Connection– How reliable transport between two hosts is
accomplished is the concern of the transport layer.
– Reliable or unreliable delivery– Examples: TCP, UDP
35
Functions of Layer 4
• TCP breaks large data into segments
• TCP marks each data packet with a sequence number
• A missing packet can be resent
36
Functions of Layer 3• Network Layer: Address and Best Path
– Provides connectivity and path selection between two host systems that may be located on geographically separated networks
– Provides logical addressing which routers use for path determination
– Examples: IP
37
Functions of Layer 2
• Data Link Layer: Access to media– Concerned with physical (as opposed
to logical) addressing– Access to media using MAC address– Error detection
38
Functions of Layer 1
• Physical Layer: Binary transmission–Moves bits between devices
39
The Seven Layers of the OSI Reference Model
• The application (upper) layers– Layer 7: Application– Layer 6: Presentation– Layer 5: Session
• The data-flow (lower) layers– Layer 4: Transport– Layer 3: Network– Layer 2: Data link– Layer 1: Physical
40
OSI Model and TCP/IP Model
41
TCP/IP Protocol Graph
42
Use of the OSI Model in the CCNA Curriculum
43
Encapsulation The lower layers use encapsulation to put the protocol data unit (PDU) from the upper layer into its data field and to add headers and trailers that the layer can use to perform its function.
44
Names for Data at Each Layer
45
De-Encapsulation
• When the data link layer receives the frame, it does the following:–It reads the physical address and
other control information provided by the directly connected peer data link layer.
–It strips the control information
46
Cisco Academy 3 References
• CCNA1 Online Materials– Slide 2 – 17 : 1.2.2 -1.2.9– Slide 18 – 23 : 2.1.5 – 2.1.7– Slide 25 - 29 : 2.2.1 – 2.2.3– Slide 30 – 45 : 2.3.2 – 2.3.7
47
Cisco Academy 4 Exploration Reference
• Networking Fundamentals– Slide 2 – 17 : 6.1.1 – 6.1.4– Slide 18 – 23 : 2.1.6 – 2.2.3– Slide 25 – 29 : 2.3.2 – 2.4.2– Slide 30 – 45 : 2.4.1 – 2.4.8
top related