1.3_datacom-ip basics packet nw

For circulation to CTO Trainees only

Data Communication

&

IP Addressing

D C Sonkhla DE (MPLS), BRBRAITT

[email protected]

[email protected]

919425800989


AGENDA

Introduction to data communication

Packet Switching Network

IP Addressing


Introduction

Data communication:

The process of sending data between two devices via some transmission medium.

Data communication is said to be local if the communicating devices are in the same building

Data communication is considered remote if the devices are farther apart.


Components of Data Communication System

The data communication system is made up of five

components

Step 1 Step 2 Step 3

Protocol

Sender Receiver

Medium

Message

Step 1 Step 2 Step 3

Protocol


Characteristics of Effective Data Comm

Delivery: The system must deliver the data to the correct destination.

Accuracy: The delivery of data must be accurate.

Timeliness : Deliver the data as exactly the same and deliver it in timely

manner.

Effective Data Communication

Delivery Accuracy Timeliness


Data Communication Network Criteria

Data Communication

Network Criteria

Performance Reliability Security

Performance: BW, Delay, Type of cable/connector used, impairment.

Reliability: Packet Drop/loss due to impairment.


Protocols

A common language that both Sender and Receiver agree

upon and communicate.

A protocol is a set of rules that govern data

communication.

Hello shall

I Speak in

French?

OK ,I can

Understand

French


Protocols

What to

communicate ?

How to

communicate ?

When to

communicate ?

Protocol


Protocols

Syntax Semantics Timing

Key Elements of a

Protocol

The order in which Data to be present. Format or Structure

How to interpret format ? what action is to be taken ?

When data should be sent and how fast ?


Standards

Essential for interconnection of different equipments from different

vendors for proper and effective Data transfer.

Approved by an organized body Adopted through widespread use

Standards

De facto

(By Facts)

De jure

(By Law)


Signals

Signals are electric or electromagnetic representations

of data.

Data are propagated from one point to another by

means of electrical signals.


Signalling

Signalling is the physical propagation of the signal along

a suitable medium.

Both data and the signals may be either Analog or

Digital.

An analog data is a continuous wave (human voice)

Digital data is data stored in the form of 0 and 1.

An analog signal is a continuous wave form that changes

smoothly over time.

A digital signal is discrete. It can have values 0 or 1.


Encoding and Decoding

Encoding is transforming data into signals to

send them on the channel from one place to

another.

Encoding:

The process of putting a sequence of data into a

specialized format for efficient transmission.

Decoding:

The conversion of an encoded format back into the

original form.


Type of Transmission

Data Transmission

Analog

Transmission

Serial

Digital

Transmission

Parallel

Asynchronous Synchronous


Asynchronous Transmission

Transmits the characters one at a time, with start bit (0)

& stop bits (1 s) at the end of each byte.

There may be a gap between bytes.

Asynchronous transmission is very slow.

The advantage of asynchronous transmission is that it is

simple and inexpensive.


Synchronous Transmission

The entire message is sent in an even flow.

The bits are sent one after another without start/stop

bits or gaps.

The receiver counts the bits as they arrive and group

them in eight bit units.

Synchronization is maintained by a clock signal on a

separate wire or modulated on the data signal extracted

from incoming bit stream.


Transmission Media

The medium which carries the signal from the sender to the

receiver.

Twisted Pair

Transmission Media

Guided Media Unguided Media

Coaxial Optic Fiber UV Radio Frequency Microwave


Twisted Pair Cable

Unshielded Twisted Pair Shielded Twisted Pair Ratings are defined by Category.


Coaxial Cable

The Coaxial cable ratings are defined by RG rating.

RG 6, RG 8, RG 11 are thicker one and RG 58, RG 59 are thinner

BNC Connectors, T Connector, In the end there would be terminator.


Fiber Optic Cable


Communication Channel Configuration

Point to point

Provides a dedicated link

Entire capacity of the channel is reserved

Point to Multi Point


Mode of Transmission

Mode Of Transmission

Simplex Half Duplex Full Duplex


DTE and DCE

Data Terminal Equipment (DTE)

any device that is a source or destination for binary

digital data.

Computers and terminals are usually DTE

A Data Circuit Terminating Equipment (DCE)

any device that transmits or receive data in the form

of an analog or digital signal through network.

Modems and communications hardware are generally

DCEs


Handshaking

Handshaking is a way to control the flow of data

between connected units.

There are two common forms of handshaking.

Hardware Handshaking

Software Handshaking

Hardware handshaking sometimes referred to as

(Request To Send (RTS) /Clear To Send (CTS))

Software handshaking referred to as (Xon/Xoff) which

uses extra characters in the data flow to achieve the

control.


Interfaces

The interfaces has four characteristics

Mechanical characteristics

The physical Characteristics pertain to the physical connection (Physical Appearance)

Electrical characteristics

Deals with the voltage levels and timing of the voltage changes.

These characteristic determine the data rate and distances that the data can reach.


Interfaces

Functional characteristics

Specify the functions that are performed by each of the interface

Procedural characteristics

specify the sequence of events for transmitting data.

some times known as logical interface which defines how the signal should be interpreted


The major organizations responsible for making

standards are:

Electronics Industries Association (EIA)

Institute of Electrical and Electronic Engineers (IEEE)

American National Standards Institute (ANSI)

Consultative Committee on International Telephone

and Telegraph (CCITT)

International Organisation for Standards (ISO)

Organizations Making Standards


Introduction

Switching technique is used for communication

of information from one end to other end.

A switched Network consists of interlinked nodes

called Switches

Switches are Hardware or Software devices

capable of creating temporary connections

between two or more devices.


Type of Switching

Switching

Circuit Switching

Packet Switching

Message Switching


Circuit Switching

Dedicated connection path is created between

the source and destination.

Designed for the real time applications.

Communication path is not shareable.

Communication path is under utilized.


Message Switching

Whether a person is available or not, it is sent.

Not real time

Telegram Systems SFT(Store & Forward

Telegraph, 16 bit), SFMSS (Store & Forward

Messaging System, 32bit)

SMS


Packet Switching

Data are made into packets before transmitting.

A packet is a unit of data that is transmitted across a packet-switched network.

Packets contain header information that includes a destination address.

A packet-switched network is an interconnected set of networks that are joined by routers.


Packet Switching

Routers in the network read destination address and forward packets along the most appropriate path to that destination.

The transmission bandwidth is dynamically allocated

Permitting many users to share the same transmission line.


Type of Packet Switching

Packet Switching

Virtual Circuit Approach

(Connection Oriented)

Datagram Approach

(Connectionless)


Connectionless Packet Switching

No connection is set up to track.

No end-to-end delivery guarantee.

No state about a packet flow between sender and receiver.

Different packets may take different paths to the destination.


Advantages

The packets are forwarded independent of other packets.

Packets are forwarded on the fly by routers, based on the most current best path to a destination.

In case of link failure the packets are quickly diverted along another path.

There may be possibilities of loss of packets, as it

may not reach to destination.

Hence quality is not guaranteed.


Connection Oriented Packet Switching

A virtual circuit is established between sender and receiver across the network before packets can start to flow.

Provides end-to-end delivery guarantee.

All the packets are transmitted by source in sequential order over the established path to destination.

Each packet is acknowledged by the destination.

A proper method is adopted to supervise the correct receipt of information.


IP ADDRESSING


AGENDA

Introduction

Dotted Decimal Notation

Hierarchical Addressing

IPv4 address classes


What is an IP Address

IP Address is Internet Protocol Address

IP was first standardized in September 1981.

It is an unique identifier for a node or a host in an IP Network.

An Internet address works like a postal address, allowing data to be routed to the chosen destination.


What is an IP Address

There are two versions

IPV4 (Now in use) 32 Bits

IPV6 (Yet to be implemented) 128 Bits

IPV4 is a 32 Bits binary address


Introduction

IP - is Internet Protocol & is responsible for :

Moving packet of data from node to node.

IP forwards each packet based on a four-byte destination

address (the IP address).

Each host on the internet is assigned a 32-bit integer

address called its internet address or IP address.

An Internet Protocol (IP) address specifies the location

of a host or client on the Internet.

The clever part of internet addressing is that the integers

are carefully chosen to make routing efficient.


Introduction

Every host and router on the internet has an IP

address, which encodes its network number and

host number.

The combination is unique: no two machines in

public domain have the same IP address.

The address is coded to allow a variable allocation

of bits to specify network and host.



The IPv4 address is 32 bits long.

What the Internet machines see an IP address? 10001100101100111101110011001000

For human understanding the 32 bits of IP address are separated into 4 bytes i.e. of 8 binary digits also called Octets.



Each binary byte is converted into decimal and is separated by a dot hence also known as Dotted Decimal Notation

How we see an IP address? 10001100.10110011.11011100.11001000

140 .179 .220 .200


Hierarchical addressing

For a protocol to be Routable, its structure must be hierarchical, i.e. every IP address must consists of at least two parts, one identifying the network and one identifying the host.

A host is an end station viz a computer workstation, a router or a printer, whereas a network consists of one or more hosts.

The Class of the address and the (subnet) mask determine which part belongs to the network address and which part belongs to the host address.


Hierarchical addressing

In decimal the address range is 0.0.0.0 to 255.255.255.255

The IP address is of the form


IPv4 Address Scheme

Two types of addressing schemes for IPv4

Classfull

Classless

Classfull

Original style of addressing based on first few bits

of the address.

Generally used in customer sites.

Classless

A new type of addressing that disregards the class

bit of an address (first 4 bits) and applies a

variable prefix (mask) to determine the network

number.


IPv4 Address Classes

H H H N Class-A:

H H N N Class-B:

H N N N Class-C:

Class-D: For Multicast

Class-E: For Research

There are five classes of addresses A, B, C, D & E.

A, B & C classes are used to represent host and network address.

Class D, E and starting with 127.x.x.x (used for loopback) addresses should not be used for Hosts.


Identifying a class of address

Address Identifier Network Address Host Address

0 7 bits Network Address 24 bits Host Address A

10 14 bits Network Address 16 bits Host Address B

110 21 bits Network Address 8 bits Host Address C

1110 Multicast address (224.0.0.0-239.255.255.255) D

1111 Reserved for future use E

By Using first 4 bits, class of address can be identified.


IP Address Bit Patterns

8 Bits 8 Bits 8 Bits 8 Bits

0-127

128-191

192-223

224-239

240-255

0 0 0 0 0 0 0 0

1 0 0 0 0 0 0 0

1 1 0 0 0 0 0 0

1 1 1 0 0 0 0 0

1 1 1 1 0 0 0 0

0 1 1 1 1 1 1 1

1 0 1 1 1 1 1 1

1 1 0 1 1 1 1 1

1 1 1 0 1 1 1 1

1 1 1 1 1 1 1 1


Class-A address

Number of Networks = 27 i.e.128 (0-127)

Network ID 0 is not used & Network ID 127 is reserved for loop back and is used for internal testing.

Number of Networks = 126

Network IDs = 1-126

Number of Hosts=224=16,777,216

hhhhhhhh hhhhhhhh hhhhhhhh 0nnnnnnn

Network Host

0 7 bits Network Address 24 bits Host Address


Class-A address

No Host ID can have all zeros i.e. 0.0.0 (network address) & all ones i.e. 255.255.255 (broadcast address).

Number of Hosts per network= 224 -2=16777214

Class A networks are referred as"/8s" network, since they have a 8-bit network-prefix


Class-B address

Number of Networks = 214 i.e.16384

Number of Hosts = 216 i.e. 65,536 (0-65,535)

No Host ID can have all zeros

i.e. 0.0 and specifies network address.

nnnnnnnn hhhhhhhh hhhhhhhh 10nnnnnn

Network Host



Class-B address

No Host ID can have all ones

i.e. 255.255 and specifies the broadcast address.

Number of Hosts per network= 216 -2=65534

Class B networks are referred as "/16s" Network,

since they have a 16-bit network-prefix

nnnnnnnn hhhhhhhh hhhhhhhh 10nnnnnn

Network Host



Class-C address

Number of Networks = 221 i.e. 2,097,152

Number of Hosts = 28 i.e. 256 (0-255)

No Host ID can have all zeros

i.e. 00000000 and specifies network address.

nnnnnnnn nnnnnnnn hhhhhhhh 110nnnnn

Network Host



Class-C address

No Host ID can have all ones

i.e. 11111111 and specifies the broadcast address.

Number of Hosts = 28-2 = 254

Class A networks are referred to as "/24s

Networks since they have a 24-bit network-prefix.

nnnnnnnn nnnnnnnn hhhhhhhh 110nnnnn

Network Host



Class-D & E addresses

Class D are special addresses are known as multicast

addresses

This address is assigned to a group of networks and not to

represent a unique address

This address is used to send IP datagrams to a group but

not to all the hosts on the network

This address is also used to address router update

messages

1110 Multicast address (224.0.0.0-239.255.255.255)

1111 Reserved (240.0.0.0-255.255.255.255)


Classfull IP Address

Class Higher Order Bit

Address range

No of Networks

No. of Hosts

Class A 0XXXXXXX 1 to 126 126 16,777,214

Class B 10XXXXXX 128 to 191 16384 65534

Class C 110XXXXX 192 to 223 2097152 254

Class D 1110XXXX 224 to 239 Multicasting

Class E 1111XXXX 240 to 254 For Future use


Identifying Address

140.179.220.200 is a Class B address so by default Network part 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).

To specify the network address, set host section to all "0"s. In our example, 140.179.0.0 specifies the

network address for 140.179.220.200.


Identifying Address

When the host section is set to all "1"s, it specifies a broadcast that is sent to all hosts on the network.

140.179.255.255 specifies the example broadcast address.


Address space utilisation

0 1

0

127

00000000

01111111

A-50%

1

0

128

191

10000000

10111111

B-25%

0

1

192

223

11000000

11011111 C-12.5%

240 255

11110000 11111111 E-6.25%

0 224

239 11100000 11101111

D-6.25% 0

1

100%


IPv6

To meet the continual growth of the Internet ,IETF has proposed a set of specifications commonly known as the next generation IP protocol (IPng or IPv6).

IPv6 increases the address size from 32 bits to 128 bits, supporting up to 3.4X1038 nodes.

It is represented using hexadecimal values separated by colons using the format X:X:X:X:X:X:X:X:, where each X refers to a four digit hexadecimal integer (16 bits each).

One such address could be BA98:7654:3210:FEDC:BA98:7654:3210:0043.


Advantages

Bigger address space

The bigger address space IPv6 offers is the most obvious enhancement over IPv4.

Allows full, unconstrained IP connectivity for today's

IP based machines

Upcoming mobile devices like PDAs and cell phones

All will benefit from full IP access through GPRS and UMTS.


Advantages

Mobility

To support Mobility a special protocol called "Mobile IP" is required for every IPv6 stack.

IPv6 supports for roaming between different networks, with global notification when you leave one network and enter the other one.


Advantages

Security

IPv6 protocol stacks are required to include IPsec.

IPsec allows authentication, encryption, and compression of IP traffic.

This allows that all applications on a machine can benefit from

Encryption

Authentication

Policies can be set on a per host (or even per-network) basis, not per application/service.


Advantages

Stateless auto configuration of hosts

Multicast

Jumbo grams

Network layer security


IPV6 address categories

Categories of IPV6 addressees

a) Unicast

b) Multicast

c) anycast

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