CCNA1 M2 Networking Fundamentals

8/2/2019 CCNA1 M2 Networking Fundamentals

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CCNA Semester1

Module 2Net w ork ing Fundam ent a l s

Objectives

Networking terminology Some network architectures The importance of bandwidth Networking models: OSI vs TCP/IP


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Networking Terminology

Relative size of network


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Networking Devices

Equipment that connects directly to a network segmentis referred to as a device.

There are 2 type of devices: end-user devices and

network devices .

Network Devices

Repeater: regenerate a signal. Hub: concentrate connections and may

regenerate a signal. Bridge: convert network transmission

data formats as well as perform basicdata transmission management.

Switch: add more intelligence to datatransfer management.

Router: routing and other services


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Network Topology

The physical topology, which is the actuallayout of the wire or media.

The logical topology , which defines how themedia is accessed by the hosts for sendingdata.

Physical Topology


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Logical Topology

Broadcast

Tok en Passing

Logical Topology: Broadcast

Each host sends its data to all other hosts onthe network medium.

First-come, first-serve. Eg: Ethernet


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Functions of Protocols

Protocols control all aspects of datacommunication, which include the following: How the physical network is built

How computers connect to the network How the data is formatted for transmission How that data is sent How to deal with errors

LANs

Operate within a limited geographic area Allow many users to access high-bandwidth

media

Provide full-time connectivity to local services Connect physically adjacent devices


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LAN Devices and Technology

Some common LAN technologies are: Ethernet Token Ring FDDI

WANs

Operate over a large geographically separated areas Provide full-time remote resources connected to local

services


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WAN Technologies Include

Some common WAN technologies are: Analog modems Integrated Services Digital Network (ISDN) Digital Subscriber Line (DSL) Frame Relay Asynchronous Transfer Mode (ATM) T (US) and E (Europe) carrier series: T1, E1, T3, E3 Synchronous Optical Network (SONET)

Metropolitan-Area Networks (MANs)

A MAN is anetwork that spansa metropolitan

area such as a cityor suburban area. A MAN usually

consists of two ormore LANs in acommongeographic area.


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Storage-Area Networks (SANs)

A SAN is a dedicated,high-performancenetwork used to movedata between serversand storage resources.

Virtual Private Networks (VPNs)

A VPN is a privatenetwork that isconstructed within apublic networkinfrastructure such asthe global Internet .

VPN is the most cost-effective method ofestablishing securedconnection


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VPN Types

There are three main types of VPNs:

Access VPNs Intranet VPNs Extranet VPNs

Bandwidth


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Importance of Bandwidth

Digital Bandwidth

Bandwidth is the measure of how muchinformation, or bits, can flow from one place toanother in a given amount of time, or seconds.


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Bandwidth Limitations (LAN)

Bandwidth Limitations (WAN)


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Throughput

Throughput refers to actual measuredbandwidth , at a specific time of day, usingspecific Internet routes, and while a specificset of data is transmitted on the network.

Factors that determine throughput: Internetworking devices Type of data being transferred Network topology Number of users on the network User computer Server computer Power conditions

Data Transfer Calculation

Calculate an estimate of network performance


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Networking Models

Analyzing network in layer

What is flowing ?Data

What is flowing ?Data

What different forms flow ?Text, Graphic, Video ...

What different forms flow ?Text, Graphic, Video ...

What rules govern flow ?Standard, Protocol ...

What rules govern flow ?Standard, Protocol ...

Where does the flow occur ?

Cable, Atmosphere ...

Where does the flow occur ?

Cable, Atmosphere ...


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Communication characteristics

Addresses What are the source and the destination of a communication

process?

Media Where does the communication take place?

Protocols How to make the communication process effectively?

SourceAddress

DestinationAddress

Medium

Packets

Protocols

Data Communication

Address Source address, Destination address

Media Cable, Fiber, Atmosphere

Protocol Format Procedure


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Evolution of networking standards

SNA

TCP/IP DECNET

Proprietary Interconnection Development Simplification

StandardStandard

OSI Model

The OSI modelThe OSI model: a framework within whichnetworking standards can be developed. It provided vendors with a It provided vendors with a set of standards set of standards that that

ensured greater compatibility and interoperability ensured greater compatibility and interoperability between the various types of network technologies between the various types of network technologies that were produced by the many companies around that were produced by the many companies around the world the world ..

Propr ie ta ryPropr ie ta ry vs .vs . OpenOpen


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Why a layered model

Reduces complexity. Standardizes interfaces. Facilitates modular engineering. Ensures technology

compatibility . Accelerates evolution . Simplifies teaching and

learning.

7 layers of the OSI reference model

Network processes to applications

Data representation

Interhost communication

End-to-end connections

Address and best path

Direct link control, aDirect link control, access to media

Binary transmission

All P eople S eem T o N eed D ata P rocessing


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Is the OSI layer that is closest to

the user; it provides networkservices to the usersapplications. File transfer Electronic mail Terminal access

Data representation


Ensures that the information thatthe application layer of onesystem sends out is readable bythe application layer of anothersystem. Format of data Data conversion Data compression Data encryption


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Establishes, manages, and

terminates sessions betweentwo communicating hosts. Sessions Dialog Conversations Data exchange




Provides reliable, transparent

transfer of data over networks. Segments, data stream, datagram End-to-end flow control Error detection and recovery Segmentation & reassembly


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Provides connectivity and

path selection between twohost systems that may belocated on geographicallyseparated networks. Packets Route, routing table, Logical address Fragmentation

Direct link control,Direct link control, access to media


Provides for the reliable transfer

of data cross a physical link. Frames Physical address Network topology Line discipline


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Binary transmission


Transmission of an

unstructured bit streamover a physical linkbetween end systems. Electrical, mechanical, procedural and

functional specifications Physical data rate Distances Physical connector



Data representation




Direct link control, aDirect link control, access to media

Binary transmission

All P eople S eem T o N eed D ata P rocessing


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Peer-to-Peer Communication

The protocols of eachlayer exchangeinformation, calledprotocol data units(PDUs ), between peerlayers .

Encapsulation

The lower layers useencapsulation to putthe protocol data

unit (PDU) from theupper layer into itsdata field and to addheaders and trailersthat the layer canuse to perform itsfunction.


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De-Encapsulation

When the data link layer receives the frame, itdoes 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 from the frame, thereby creating adatagram.

It passes the datagram up to the next layer, following theinstructions that appeared in the control portion of the frame.

Encapsulation example: E-mail


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Layer-to-layer communications

Request services

Provide services

TCP/IP model development

The late-60s The Defense AdvanceResearch Projects Agency (DARPA)originally developed Transmission Control

Protocol/Internet Protocol (TCP/IP) tointerconnect various defense departmentcomputer networks.

The Internet, an International Wide AreaNetwork, uses TCP/IP to connect networksacross the world.


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The TCP/IP Reference Model

Layer 4: Layer 3: Layer 2: Layer 1:

It is important to note that some of the It is important to note that some of the layers in the TCP/IP model have the same layers in the TCP/IP model have the same

name as layers in the OSI model.name as layers in the OSI model.Do not confuse the layers of the two models.Do not confuse the layers of the two models.

TCP/IP Protocol Stack


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Summary

Networking devices Some of the common network types Intranet and extranet Bandwidth and throughput The layered communication model OSI reference model TCP/IP networking model

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CCNA1 M2 Networking Fundamentals