(19a) Networking Handout

8/13/2019 (19a) Networking Handout

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Networking

Basics

byS.MuthusamiDDE, STI(T)


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What is Networking?

Connecting two or more computers

Types of Networking LAN (Local Area Network)

Normally within a building

Connection orientedWireless


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What is Networking?

WAN (Wide area network)

between two branches in different citiesdedicated lines(Costly but slower than LA

VPN (Virtual private network)

between two branches in different cities

public network (Cheaper than WAN butthan LAN)


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Why Networking?

Purpose of Networking

Sharing of files Sharing of resources

Sharing of programs

Users communicate with each other

Video conferencing


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Why Networking? Contd

Entertainment, distributed games Audio & video streaming

Doom and other games

Commerce Ticket booking, Purchase of articles and ba

Automation of business processes

Control of equipment Domestic like washing machine, Microwav


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Terminology

Local networks are called LANs

A computer connected to a LAN is known as

A computer is turned on and can access theis said to be online.

LAN and Internet are different

Internet is a group of large networks

Two modes of configuration in a network

Client Server model (Domain)

Peer to Peer model (Workgroup)


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Domain Configuration

DC ADC

Workstation

Switch

Workstation Work


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Features of a Domain

Suited for large Networks Increased security by central authentication

Access control with NTFS file system Disk quota

Remote access DNS

DHCP Mailing facility

Costly operating system


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Peer to Peer model

SwitchWorkstation Wor

Wor

Workstation


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Features of a Peer to peer

Suited for Small Networks up to ten compute

Share level Access control Cheaper operating system

Easier to maintain

No Administrator

Static IP addresses


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Network infrastructure

Physical

Network interface card

Cables

Switches/Hubs

RoutersConnectors

Logical

Operating system

protocols


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UTP cable


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ScTP cable


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UTP cables

C


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Connectors

T l


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1. Bus topology

Topology

2. St

3. Ring to

N t k i ti


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Network communication

Communication between two computers in a networ

OSI reference model (Open Systems InterconnectReference Model (1984))

standardization of the various protocols used in comnetworks by the International Standards Organizati

TCP/IP model or DOD model


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The OSI model

Application layer

Transport

Network

Link


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The OSI model


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The Physical Layer

Responsibility: transmission of raw bits over a communication

channel. Issues:

mechanical and electrical interfaces time per bit

distances

The Data Link Layer


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The Data Link Layer -

Data Link Control

Responsibility: provide an error-free communication link

Issues:framing (dividing data into chunks) header & trailer bits

addressing

10110110101 01100010011 1011000

The Data Link Layer


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The Data Link Layer -

The MAC sublayer

Medium Access Control - needed by mutiaccnetworks.

MAC provides DLC with virtual wires on

multiaccess networks.

Th N k L


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The Network Layer

Responsibilities:

path selection between end-systems (routing). subnet flow control.

fragmentation & reassembly translation between different network types.

Issues:packetheaders

virtual circuits

Th T L


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The Transport Layer

Responsibilities:

provides virtual end-to-end links between peerprocesses.

end-to-end flow control Issues:

headers error detection

reliable communication

Th S i L


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The Session Layer

Responsibilities: establishes, manages, and terminates sessions be

applications.

service location lookup

Many protocol suites do not include a session

layer.

Th P t ti L


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The Presentation Layer

Responsibilities: data encryption

data compression data conversion

Many protocol suites do not include a PresenLayer.

Th A li ti L


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The Application Layer

Responsibilities: anything not provided by any of the other layers

Issues: application level protocols

appropriate selection of type of service

Network Address


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Network Address

Every host connected to a network should have aaddress for interconnectivity

IP addresses are unique logical addresses (not p 32 bits.( 4 octets in dotted decimal notation)

Includes a network ID and a host ID.

Every host must have a unique host ID in its IP ad

IP addresses are assigned by a central authority

Internet numbers assigning authority) Subnet masks are to identify the network ID and h

Eg: For Class C network 255.255.255.0Class B network 255.255.0.0

Network Address


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Network Address

Every Ethernet interface has a unique 48 bit a

also (MAC address a.k.a. hardware address).

Example: C0:B3:44:17:21:17 Switches use this address for switching

IP Address


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IP Address

0NetID

10

110 NetID

1110 Multicast Address

HostID

NetID HostID

HostID

ClassClassAA

BB

CC

DD8 bits 8 bits 8 bits8 bits

0

12

1

22

241111 ResearchEE

Eg: 192.128.16.1

Class A B&C IP Address


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Class A,B&C IP Address

Class A 128 possible network IDs

over 4 million host IDs per network ID

Class AClass A 128 possible network IDs

over 4 million host IDs per networkID

Class BClass B 16K possible network IDs

64K host IDs per network ID

Class CClass C over 2 million possible network IDs

about 256 host IDs per network ID

Network ID and Host ID


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Network ID and Host ID

A Network ID is assigned to an organization by authority.

Host IDs are assigned locally by the system adm Both the Network ID and the Host ID are used fo

A single network interface is assigned a single IPcalled the hostaddress.

A host may have multiple interfaces, and therefohostaddresses.

Hosts that share a network all have the same IP naddress (the network ID).

Subnetting


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Subnetting

router

Subnet A192.168.1.0

Subnet B192.168.2.0

Subnet C192.168.3.0

Process summary


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Process summary

Letter

Letter

Addressed

Envelope

Addressed

Envelope


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Thank You

Documents

(19a) Networking Handout