Combinepdf (1)

An
Industry Internship Report
At
BHARAT SANCHAR NIGAM LIMITED (BSNL)
On
“VT ON ADVANCE IP NETWORKING”
In the fulfillment of the Eight semester Industry Internship
For
ELECTRICAL E NGI NE ERI NG
S ubmi tted
By:
BARIN RAJ DASH
Prof. Durga Prasanna Mohanty
(Head Of Department)
DEPARTMENT OF ELECTRICAL ENGINEERING,
RAAJDHANI ENGINEERING COLLEGE,
BHUBANESWAR-751017, ODISHA
BIJU PATNAIK UNIVERSITY OF TECHNOLOGY
ROURKELA ODISHA-769004
(2018-2021)

BIJU PATNAIK UNIVERSITY OF TECHNOLOGY ROURKELA ODISHA
RAAJDHANI ENGINEERING COLLEGE, BHUBANESWAR
CERTIFICATE
On the basis of declaration submitted by BARIN RAJ DASH , student of B.Tech
Electrical Engineering, Eighth semester, batch 2020-21, I herebycertify that the
Internship titled “VT ON ADVANCE IP NETWORKING”, which is submitted in
Department of Electrical Engineering, Raajdhani Engineering College, Biju
Patnaik University of Technology Odisha , in fulfilment of Eighth semester
industry internship is an original contribution with existing knowledge &faithful
record carried out by him under my guidance supervision.
Prof. Durga Prasanna Mohanty Prof. Durga Prasanna Mohanty
Head of Department Head of Department
Department of Electrical Engineering Department of Electrical Engineering
Raajdhani Engineering College, Bhubaneswar Raajdhani Engineering College, BBSR
Place: BBSR
Date:

DECLARATION
I, BARIN RAJ DASH, student of B. Tech Electrical Engineering Eighth semester,
hereby declare that the term paper titled “VT ON ADVANCE IP NETWORKING”, is submitted by
me to Department of Electrical Engineering, Raajdhani Engineering College,
Bhubaneswar, BIJU PATNAIK UNIVERSITY OF TECHNOLOGY, ROURKELA, in partial
fulfillment of Eighth semester industry internship. Thisis a comprehensive study based on the
literature survey & brief review on existing knowledge, which is produced in best possible
manner.
SIGNATURE OF STUDENT
Place: Bhubaneswar NAME: BARIN RAJ DASH
Date: REGD NO: 1701294074

Acknowledgement
“There are people, who, simply by being what they are, influence encourage &
inspire you to do things you never thought yourself capable of doing….”
Among these are my teachers, friends & family members to whom I wish
to extendmy gratitude on the event of completing my term Internship Report.
Through the columns of this Internship Report, I would like to take the opportunity
to thank SARAJU PRASAD PADHY(Director) for encouraging us in doing the
summertraining. I would also like to thank Prof. Durga Prasanna Mohanty (HOD,
Department of Electrical Engineering) who gave us valuable suggestions during the
execution of the Internship.
I would like to thank my external guide MISS. SMITA BISWA (Training
Coordinator) and Prof. Durga Prasanna Mohanty (HOD) mentor who
collaborated with me in bringing this Internship in its present form. They have been
a great source of help & have cleared all our doubts thus being a great support in
every respect.
I would also like to mention the support of my friends & family members for
giving me useful suggestions & contributed a lot to this file without whose endless
efforts this work would ever have been possible. At last, I would like to thank all
those around me who helped me in any way to bring the Internship in its present
form.
Any suggestions for the improvement of this Internship file would be
highly accepted.
BARIN RAJ DAS
B. TECH ELECTRICAL ENGINEERING
REGD NO: 1701294074

CONTENTS
BASIC NETWORKING CONCEPTS
➢ STRUCTURE
➢ INTRODUCTION
➢ OBJECTIVE
➢ WHAT IS A COMPUER NETWORK?
➢ TYPES OF NETWORKS
➢ CATEGORIES OF NETWORK
➢ OSI MODEL
➢ NETWORK CABLINGS
➢ NETWORKARCHITECTURE
➢ NETWORK TOPOLOGIES
➢ NETWORKING PROTOCOLS
➢ SUMMARY
➢ SELF ASSESSMENT QUESTIONS
➢ REFERENCES AND SUGGESTED FURTHER READING
NETWORKING COMPONENTS
➢ STRUCTURE
➢ INTRODUCTION
➢ OBJECTIVE
➢ LAN ARCHITECTURE
➢ LAN TOPOLOGIES
➢ MEDIA ACCESS CONTROL
➢ LOGICAL LINK CONTROL
➢ BASIC NETWORKING COMPONENTS
➢ WIRELESS LAN
➢ SUMMARY
IPV4 ADDRESSING

➢ STRUCTURE
➢ INTRODUCTION
➢ OBJECTIVE
➢ IPV4 ADDRESS
➢ IPV4 ADDRESSING SCHEME
➢ SUBNETTING
➢ VLSM
➢ CIDR
➢ PUBLIC & PRIVATE IP ADDRESS
➢ SUMMARY
IPV6 BASICS
➢ STRUCTURE
➢ INTRODUCTION
➢ OBJECTIVE
➢ LIMITATIONS OF IPV4
➢ FEATURES OF IPV6
➢ SUMMARY
OSI MODEL
➢ STRUCTURE
➢ INTRODUCTION
➢ OBJECTIVE
➢ ISO MODEL
➢ LAYERED ARCHITECTURE
➢ LAYERS OF OSI MODEL
➢ SUMMARY
TCP/IP MODEL
➢ STRUCTURE
➢ INTRODUCTION
➢ OBJECTIVE
➢ TCP/IP MODEL
➢ LAYERS OF TCP/IP MODEL

➢ FUNCTIONS OF LAYERS
➢ MAJOR TCP/IP PROTOCOLS
➢ TCP/IP NETWORK LAYER PROTOCOL
➢ TCP/IP TRANSPORT LAYER PROTOCOL
➢ COMPARISON OF OSI AND TCP/IP MODEL
NIB OVERVIEW
➢ STRUCTURE
➢ INTRODUCTION
➢ OBJECTIVE
➢ NIB PROJECT
➢ BROADBAND MULTIPLAY COMPONENTS
➢ SUMMARY
VLAN
➢ STRUCTURE
➢ INTRODUCTION
➢ OBJECTIVE
➢ LAYER 2 SWITCHED NETWORK
➢ SUMMARY
➢ BROADBAND NETWORK ARCHITECTURE AND COMPONENTS
STATIC & DYNAMIC IP ADDRESSING
➢ INTRODUCTION
➢ OBJECTIVE
➢ WHAT IS DHCP
➢ THE NEED FOR DHCP AND DHCP GOALS
➢ DHCP METHODS OF IMPLEMENTATION
➢ HOW DHCP WORKS
➢ INTERACTIONS BETWEEN CLIENT AND SERVER
➢ IMPLEMENTING DHCP-EXAMPLES DHCP SOFTWARE
DSLAM
➢ STRUCTURE
➢ INTRODUCTION

➢ OBJECTIVE
➢ FEATURES OF DSLAM
➢ IMPLEMENTATION OF DSLAM
➢ CONNECTIVITY OF DSLAM
➢ ARCHITECTURE OF DSLAM
➢ AN 2000-IB IP DSLAM
➢ IP VIRTUAL PRIVATE NETWORKING
ROUTER ARCHITECTURE
➢ STRUCTURE
➢ INTRODUCTION
➢ OBJECTIVE
➢ WHAT IS ROUTER?
➢ EVOLUTION
➢ ROUTER COMPONENTS AND ITS FUNCTIONS
➢ ROUTER COMMANDS
ADSL TECHNOLOGY
➢ STRUCTURE
➢ INTRODUCTION
➢ OBJECTIVE
➢ ADSL
➢ WHY ADSL?
➢ HOW ADSL WORKS?
➢ ADSL MODULATION
ROUTING PRINCIPLES
➢ STRUCTURE
➢ INTRODUCTION
➢ OBJECTIVE
➢ ROUTING PROCESS
➢ ROUTING PROTOCOL
➢ ROUTING TYPES
➢ ROUTING ALGORITHMS

JUMPERING ARRANGEMENT AT MDF FOR NEW & EXISTING CUSTOMER
➢ STRUCTURE
➢ INTRODUCTION
➢ OBJECTIVE
➢ MDF
➢ LINE PARAMETERS
MEASUREMENT OF SPEEDOF BROADBAND CONNECTION
➢ STRUCTURE
➢ INTRODUCTION
➢ OBJECTIVE
➢ MECHANISM OF SPEED MEASUREMENT
➢ UP/DOWN CONNECTION SPEED MEASUREMENT
➢ TOOLS FOR MEASUREMENT
CYBER SECURITY AN OVERVIEW
➢ STRUCTURE
➢ INTRODUCTION
➢ NETWORK SCENARIO
➢ WHAT IS CYBER SECURITY?
➢ HACKER
➢ VULNERABILITY
➢ VARIOUS SECURITY THREATS
➢ INTERNET ATTACKS
➢ SECURITY PROCESS & TOOLS
➢ VIRUSES
➢ COMPUTER WORMS
➢ TROJAN HORSES
➢ ZOMBIE COMPUTER
➢ DENIAL OF SERVICE (DOS)
➢ SPAMS
➢ SPOOFING
➢ PHISHING

➢ SPYWARE
➢ KEY LOGGER
➢ ELEVATION OF PRIVILEGE
TROUBLESHOOTING BROADBAND CONNECTION
➢ STRUCTURE
➢ INTRODUCTION
➢ OBJECTIVE
➢ IDENTIFICATION OF CONNECTION ERROR
➢ TROUBLESHOOTING
➢ FREQUENTLY ASKED QUESTIONS
DESKTOP SECURITY
➢ STRUCTURE
➢ INTRODUCTION
➢ WHY DO YOU NEED TO SECURE YOUR DESKTOP?
➢ SOFTWARE INSTALLATION
➢ GUIDELINES FOR PHYSICAL SECURITY
➢ GUIDELINES FOR INTERNET SECURITY
➢ GUIDELINES FOR DATA SECURITY
➢ GUIDELINES FOR BROWSER SECURITY
➢ GUIDELINES FOR e-mail SECURITY
➢ GUIDELINES FOR WIRELESS SECURITY
➢ GUIDELINES FOR MODEM SECURITY
• Do’s
• Don’ts
• SETUP
➢ HOW TO CONNECT A WIRELESS MODEM TO A DESKTOP COMPUTER
➢ SETTING UP THE WIRELESS MODEM

BASIC NETWORKING CONCEPTS
INTRODUCTION
Without a network, you can access resources only on your own computer. These resources may be
devices in your computer, such as a folder or disk drive, or they may be connected to your computer,
such as a printer or CDROM drive. These devices, accessible only to you, are local resources.
Networking allows you to share resources among a group of computer users.
OBJECTIVE
After reading this unit, you should be able to understand: basic networking concepts such as Types
of Networks, Categories of Network, Network Cablings, Network Architectures,
Network Topologies, Networking Protocols, Data Transmission-Transmission modes,
Signal coding Techniques, Signal Conversion, Multiple Signal Transmission Schemes (Multiplexing),
Networking Standards, Examining your Network with commands etc.
WHAT IS A COMPUTER NETWORK?
A network is any collection of independent computers that communicate with one another over a
shared network medium. A computer network is a collection of two or more connected computers.
When these computers are joined in a network, people can share files and peripherals such as
modems, printers, tape backup drives, or CD-ROM drives. When networks at multiple locations are
connected using services available from phone companies, people can send e-mail, share links to the
global Internet, or conduct video conferences in real time with other remote users.
When a network becomes open sourced it can be managed properly with online collaboration
software. As companies rely on applications like electronic mail and database management for core
business operations, computer networking becomes increasingly more important.
EVERY NETWORK INCLUDES
➢ At least two computers Server or Client workstation.
➢ Networking Interface Card's (NIC)
➢ A connection medium, usually a wire or cable, although wireless communication between
networked computers and peripherals is also possible.
➢ Network Operating system software, such as Microsoft Windows NT or 2000 or Novell
NetWare or Unix / Linux Compatibility
TYPES OF NETWORKS
LANS (LOCAL AREA NETWORKS)
A network is any collection of independent computers that communicate with one another over a
shared network medium. LANs are networks usually confined to a geographic area, such as a single
building or a college campus. LANs can be small, linking as few as three computers, but often link
hundreds of computers used by thousands of people. The development of standard networking
protocols and media has resulted in worldwide proliferation of LANs throughout business and
educational organizations.

WANS (WIDE AREA NETWORKS)
Wide area networking combines multiple LANs that are geographically separate. This is
accomplished by connecting the different LANs using services such as dedicated leased phone lines,
dial-up phone lines (both synchronous and asynchronous), satellite links, and data packet carrier
services. Wide area networking can be as simple as a modem and remote access server for employees
to dial into, or it can be as complex as hundreds of branch offices globally linked using special routing
protocols and filters to minimize the expense of sending data sent over vast distances.
INTERNET
The Internet is a system of linked networks that are worldwide in scope and facilitate data
communication services such as remote login, file transfer, electronic mail, the World Wide Web and
newsgroups. With the meteoric rise in demand for connectivity, the Internet has become a
communications highway for millions of users. The Internet was initially restricted to military and
academic institutions, but now it is a full-fledged conduit for any and all forms of information and
commerce. Internet websitesnow provide personal, educational, political and economic resources to
every corner of the planet.
connectivity, the Internet has become a communications highway for millions of users. The Internet
was initially restricted to military and academic institutions, but now it is a full-fledged conduit for
any and all forms of information and commerce. Internet websites now provide personal, educational,
political and economic resources to every corner of the planet.
3.4.4 INTRANET
With the advancements made in browser-based software for the Internet, many private organizations
are implementing intranets. An intranet is a private network utilizing Internet-type tools, but

available only within that organization. For large organizations, an intranet provides an easy access
mode to corporate information for employees.
3.4.5 MANS (METROPOLITAN AREA NETWORKS)
The refers to a network of computers with in a City.
3.4.6 VPN (VIRTUAL PRIVATE NETWORK)
VPN uses a technique known as tunnelling to transfer data securely on the Internet to a remote access
server on your workplace network. Using a VPN helps you save money by using the public Internet
instead of making long–distance phone calls to connect securely with your private network. There are
two ways to create a VPN connection, by dialling an Internet service provider (ISP), or connecting
directly to Internet.
CATEGORIES OF NETWORK
Network can be divided in to two main categories
PEER-TO-PEER MODEL
In peer-to-peer networking there are no dedicated servers or hierarchy among the
computers. All of the computers are equal and therefore known as peers. Normally each computer
serves as Client/Server and there is no one assigned to be an administrator responsible for the entire
network.
Peer-to-peer networks are good choices for needs of small organizations where the users are allocated
in the same general area, security is not an issue and the organization and the network will have
limited growth within the foreseeable future
SERVER – CLINET MODEL
The term Client/server refers to the concept of sharing the work involved in processing data between
the client computer and the most powerful server computer.
The client/server network is the most efficient way to provide:
Databases and management of applications such as Spreadsheets, Accounting, Communications
and Document management.
Network management.
Centralized file storage.
The client/server model is basically an implementation of distributed or cooperative processing. At
the heart of the model is the concept of splitting application functions between a client and a server
processor. The division of labor between the different processors enables the application designer to
place an application function on the processor that is most appropriate for that function. This lets the
software designer optimize the use of processors--providing the greatest possible return on
investment for the hardware. Client/server application design also lets the application provider mask
the actual location of application function. The user often does not know where a specific operation
is executing. The entire function may execute in either the PC or server, or the function may be split
between them. This masking of application function locations enables system implementers to

upgrade portions of a system over time with a minimum disruption of application operations, while
protecting the investment in existing hardware and software.
THE OSI MODEL
Open System Interconnection (OSI) reference model has become an International standard and serves
as a guide for networking. This model is the best known and most widely used guide to describe
networking environments. Vendors design network productsbased on the specifications of the OSI
model. It provides a description of how network hardware and software work together in a layered
fashion to make communications possible. It also helps with trouble shooting by providing a frame
of reference that describes how components are supposed to function.
There are seven to get familiar with and these are the physical layer, data link layer, network layer,
transport layer, session layer, presentation layer, and the application layer.
PHYSICAL LAYER:
This Layer is just that the physical parts of the network such as wires, cables, and there media
along with the length. Also, this layer takes note of the electrical signals that transmit data throughout
system.
DATA LINK LAYER
This layer is where we actually assign meaning to the electrical signals in the network. The layer also
determines the size and format of data sent to printers, and other devices. Also, I don't want to forget
that these are also called nodes in the network. Another thing to consider in this layer is will also
allow and define the error detection and correction schemes that ensure data was sent and received.
NETWORK LAYER
This layer provides the definition for the connection of two dissimilar networks.
TRANSPORT LAYER
This layer allows data to be broken into smaller packages for data to be distributed and addressed to
other nodes (workstations).

SESSION LAYER
This layer helps out with the task to carry information from one node (workstation) to another
node (workstation). A session has to be made before we can transport information to another
computer.
PRESENTATION LAYER
This layer is responsible to code and decode data sent to the node.
APPLICATION LAYER
This layer allows you to use an application that will communicate with say the operation system of a
server. A good example would be using your web browser to interact with the operating system on a
server such as Windows NT, which in turn gets the data you requested.
NET WORK CABLINGS
In the network you will commonly find three types of cables used these are the, coaxial cable, fibre
optic and twisted pair.
THICK COAXIAL CABLE
This type cable is usually yellow in colour and used in what is called thick nets, and has two
conductors. This coax can be used in 500-meter lengths. The cable itself is made up of a solid centre
wire with a braided metal shield and plastic sheathing protecting the rest of the wire.
THIN COAXIAL CABLE
As with the thick coaxial cable is used in thick nets the thin version is used in thin nets. This type cable
is also used called or referred to as RG-58. The cable is really just a cheaper version of the thick cable.
FIBER OPTIC CABLE
As we all know fibre optics are pretty darn cool and not cheap. This cable is smaller and can carry a
vast amount of information fast and over long distances.
TWISTED PAIR CABLES
These come in two flavours of unshielded and shielded.
SHIELDED TWISTED PAIR (STP)
Is more common in high-speed networks. The biggest difference you will see in the UTP and STP is
that the STP uses metallic shield wrapping to protect the wire from interference.
Something else to note about these cables is that they are definedin numbers also. The bigger the
number the better the protection from interference. Most networks should go with no less than a CAT
3 and CAT 5 is most recommended

Now you know about cables we need to know about connectors. This is pretty important and you
will most likely need the RJ-45 connector. This is the cousin of the phone jack connector and looks real
similar with the exception that the RJ-45 is bigger. Most commonly your connector is in two flavours
and this is BNC (Bayonet Naur Connector) used in thick nets and the RJ-45 used in smaller networks
using UTP/STP.
UNSHIELDED TWISTED PAIR (UTP)
This is the most popular form of cables in the network and the cheapest form that you can go with.
The UTP has four pairs of wires and all inside plastic sheathing. The biggest reason that we call it
Twisted Pair is to protect the wires from interference from themselves. Each wire is only protected
with a thin plastic sheath.
ETHERNET CABLING
Now to familiarize you with more on the Ethernet and it's cabling we need to look at the 10's. 10Base2,
is considered the thin Ethernet, thin net, and thin wire which uses light coaxial cable to create a 10
Mbps network. The cable segments in this network can't be over 185 meters in length. These cables
connect with the BNC connector. Also, as a note these unused connections must have a terminator,
which will be a 50-ohm terminator.
10Base5, this is considered a thick net and is used with coaxial cable arrangement such as the BNC
connector. The good side to the coaxial cable is the high-speed transfer and cable segments can be up
to 500 meters between nodes/workstations. You will typically see the same speed as the 10Base2 but
larger cable lengths for more versatility.
10BaseT, the “T” stands for twisted as in UTP (Unshielded Twisted Pair) and uses this for 10Mbps of
transfer. The down side to this is you can only have cable lengths of 100 meters between
nodes/workstations. The good side to this network is they are easy to set up and cheap! This is why
they are so common an ideal for small offices or homes.
100BaseT, is considered Fast Ethernet uses STP (Shielded Twisted Pair) reaching data transfer of
100Mbps. This system is a little more expensive but still remains popular as the 10BaseT and cheaper
than most other type networks. This on of course would be the cheap fast version.
10BaseF, this little guy has the advantage of fiber optics and the F stands for just that. This
arrangement is a little more complicated and uses special connectors and NIC's along with hubs to
create its network. Pretty darn neat and not to cheap on the wallet. An important part of designing
and installing an Ethernet is selecting the appropriate Ethernet medium. There are four major types
of media in use today: Thick wire for 10BASE5 networks, thin coax for 10BASE2 networks, unshielded
twisted pair (UTP) for 10BASE-T networks and fiber optic for 10BASE-FL or Fiber-Optic Inter-
Repeater Link (FOIRL) networks. This wide variety of media reflects the evolution of Ethernet and
also points to the technology's flexibility. Thick wire was one of the first cabling systems used in
Ethernet but was expensive and difficult to use. This evolved to thin coax, which is easier to work
with and less expensive

NETWORK ARCHITECTURES
ETHERNET
Ethernet is the most popular physical layer LAN technology in use today. Other LAN types include
Token Ring, Fast Ethernet, Fibre Distributed Data Interface (FDDI), Asynchronous Transfer Mode
(ATM) and Local Talk. Ethernet connection is popular because it strikes a good balance between
speed, cost and ease of installation. These benefits, combined with wide acceptance in the computer
marketplace and the ability to support virtually all popular network protocols, make Ethernet an
ideal networking technology for most computer users today. The Institute for Electrical and
Electronic Engineers (IEEE) defines the Ethernet standard as IEEE Standard 802.3. This standard
defines rules for configuring an Ethernet network as well as specifying how elements in an Ethernet
network interact with one another.
By adhering to the IEEE standard, network equipment and network protocols can communicate
efficiently.
FAST ETHERNET
For Ethernet networks that need higher transmission speeds, the Fast Ethernet standard (IEEE 802.3u)
has been established. This standard raises the Ethernet speed limit from 10 Megabits per second
(Mbps) to 100 Mbps with only minimal changes to the existing cable structure. There are three types
of Fast Ethernet: 100BASE-TX for use with level 5 UTP cable, 100BASE-FX for use with fibre-optic
cable, and 100BASE-T4 which utilizes an extra two wires for use with level 3 UTP cable. The 100BASE-
TX standard has become the most popular due to its close compatibility with the 10BASE-T Ethernet
standard. For the network manager, the incorporation of Fast Ethernet into an existing configuration
presents a host of decisions. Managers must determine the number of users in each site on the network
that need the higher throughput, decide which segments of the backbone need to be reconfigured
specifically for 100BASE-T and then choose the necessary hardware to connect the 100BASE-T
segments with existing 10BASE-T segments. Gigabit Ethernet is a future technology that promises a
migration path beyond Fast Ethernet so the next generation of networks will support even higher data
transfer speeds.

TOKEN RING
Token Ring is another form of network configuration which differs from Ethernet in that all messages
are transferred in a unidirectional manner along the ring at all times. Data is transmitted in tokens,
which are passed along the ring and viewed by each device. When a device sees a message addressed
to it, that device copies the message and then marks that message as being read. As the message makes
its way along the ring, it eventually gets back to the sender who now notes that the message was
received by the intended device. The sender can then remove the message and free that token for use
by others. Various PC vendors have been proponents of Token Ring networks at different times and
thus these types of networks have been implemented in many organizations.
FDDI
FDDI (Fibre-Distributed Data Interface) is a standard for data transmission on fibre optic lines in a
local area network that can extend in range up to 200 km (124 miles). The FDDI protocol is based on
the token ring protocol. In addition to being large geographically, an FDDI local area network can
support thousands of users.

NETWORK TOPOLOGIES
WHAT IS A NETWORK TOPOLOGY?
A network topology is the geometric arrangement of nodes and cable links in a LAN, there are
topologies to think about when you get into networks. These are the bus, ring, star , start bus and
mesh.
BUS TOPOLOGY
In Bus bus topology, each node (computer, server, peripheral etc.) attaches directly to a common cable.
This topology most often serves as the backbone for a network. In some instances, such as in
classrooms or labs, a bus will connect small workgroups. Each node is daisy-chained (connected one
right after the other) along the same backbone, similar to Christmas lights. Information sent from a
node travels along the backbone until it reaches its destination node. Each end of a bus network must
be terminated with a resistor to keep the signal that is sent by a node across the network from
bouncing back when it reaches the end of the cable.
RING TOPOLOGY
Ring, a ring topology features a logically closed loop. Data packets travel in a single direction around
the ring from one network device to the next. Each network device acts as a repeater, meaning it
regenerates the signal. Like a bus network, rings have the nodes daisy-chained. The difference is that
the end of the network comes back around to the first node, creating a complete circuit. In a ring
network, each node takes a turn sending and receiving information through the use of a token. The
token, along with any data, is sent from the first node to the second node, which extracts the data
addressed to it and adds any data it wishes to send. Then, the second node passes the token and data
to the third node, and so on until it comes back around to the first node again. Only the node with the
token is allowed to send data. All other nodes must wait for the token to come to them.
STAR TOPOLOGY
Star, in a star topology each node has a dedicated set of wires connecting it to a central network hub.
Since all traffic passes through the hub, the hub becomes a central point for isolating network
problems and gathering network statistics. In a star network, each node is connected to a central
device called a hub. The hub takes a signal that comes from any node and passes it along to all the

other nodes in the network. A hub does not perform any type of filtering or routing of the data. It is
simply a junction that joins all the different nodes
STAR BUS TOPOLOGY
Probably the most common network topology in use today, star bus combines elements of the star
and bus topologies to create a versatile network environment. Nodes in particular areas are connected
to hubs (creating stars), and the hubs are connected together along the network backbone (like a bus
network). Quite often, stars are nested within stars, as seen in the example below:
MESH TOPOLOGY
Mesh topologies involve the concept of routes. Unlike each of the previous topologies, messages sent
on a mesh network can take any of several possible paths from source to destination. (Recall that even
in a ring, although two cable paths exist, messages can only travel in one direction.) Some WANs,
most notably the Internet, employ mesh routing.
A mesh network in which every device connects to every other is called a full mesh. As shown in the
illustration below, partial mesh networks also exist in which some devices connect only indirectly to
others.
Mesh topologies are important for large-peer-to-peer systems that use low-power transceivers. The
Quality of Service (QoS) in such systems is known to decrease as the scale increases. This present a
scalable approach for dissemination that exploits all the shortest paths between a pair of nodes and
improves the QoS. Despite the presence of multiple shortest paths in a system, we show that these
paths cannot be exploited by spreading the messages over the paths in a simple round-robin manner;
nodes along one of these paths will always handle more messages than the nodes along the other
paths scale.
NETWORKING PROTOCOLS
Networking protocols are standards that allow computers to communicate. A protocol defines how
computers identify one another on a network, the form that the data should take in transit, and how
this information is processed once it reaches its final destination. Protocols also define procedures for
handling lost or damaged transmissions or "packets." TCP/IP (for UNIX, Windows NT, Windows 95
and other platforms), IPX (for Novell NetWare), DEC net (for networking Digital Equipment Corp.
computers), AppleTalk (for Macintosh computers), and NetBIOS/NetBEUI (for LAN Manager and
Windows NT networks) are the main types of network protocols in use today. Although each network
protocol is different, they all share the same physical cabling. This common method of accessing the
physical network allows multiple protocols to peacefully coexist over the network media, and allows

the builder of a network to use common hardware for a variety of protocols. This concept is known
as "protocol independence,
Some Important Protocols and their job:
Protocol Acronym Its Job
Point-To-Point TCP/IP The backbone protocol of the internet.
Popular also for intranets using the internet
Transmission Control
Protocol/internet Protocol
TCP/IP The backbone protocol of the internet.
Popular also for intranets using the internet
Internetwork Package
Exchange/Sequenced Packet
Exchange
IPX/SPX This is a standard protocol for NovellNetwork
Operating System
NetBIOS Extended User
Interface
NetBEUI This is a Microsoft protocol that doesn't
support routing to other networks
File Transfer Protocol FTP Used to send and receive files from aremote
host
Hyper Text Transfer
Protocol
HTTP Used for the web to send documents thatare
encoded in HTML.
Network File Services NFS Allows network nodes or workstations to access
files and drives as if they were their own.
Simple Mail Transfer
Protocol
SMTP Used to send Email over a network
Telnet Used to connect to a host and emulate a terminal
that the remote server can recognize

NETWORKING COMPONENTS
INTRODUCTION
Networking means interconnection of computers. These computers can be linked together for
different purposes and using a variety of different cabling types.
The basic reasons why computers need to be networked are:
➢ to share resources (files, printers, modems, fax machines etc.)
➢ to share application software (MS Office, Adobe Publisher etc.)
➢ increase productivity (makes it easier to share data amongst users)
Small networks are often called Local Area Networks (LAN). A LAN is a network allowing easy access
to other computers or peripherals. The typical characteristics of a LAN are:
➢ physically limited distance (< 2km)
➢ high bandwidth (> 1mbps)
➢ inexpensive cable media (coaxial or twisted pair)
➢ data and hardware sharing between users
➢ owned by the user
The factors that determine the nature of a LAN are:
➢ Topology
➢ Transmission medium
OBJECTIVE
After reading this unit, you should be able to understand:
➢ The concept of Computer LAN
➢ LAN Architecture
➢ LAN Topology
➢ Various components of LAN
LAN ARCHITECTURE
The layered protocol concept can be employed to describe the architecture of a LAN, wherein each
layer represents the basic functions of a LAN. LAN protocols are concerned primarily with the lower
layers of the OSI model.
The lowest layer of the IEEE 802 reference model corresponds to the physical layer of the OSI model,
and includes the following functions:
➢ Encoding/ decoding of signals
➢ Preamble generation/ removal (for synchronisation)
➢ Bit transmission/ reception
The physical layer of the 802 model also includes a specification for the transmission medium and the
topology. Generally, this is considered below the lowest layer of the OSI model. However, the choice
of the transmission medium and topology is critical in LAN design, and so a specification of the
medium is included.

Above the physical layer are the functions associated with providing service to the LAN users. These
comprise:
➢ Assembling data into a frame with address and error-detection fields for onward
transmission.
➢ Disassemble frame, perform address recognition and error detection during reception.
➢ Supervise and control the access to the LAN transmission medium.
➢ Provide an interface to the higher layers and perform flow control and error control.
The above functions are typically associated with OSI layer 2. The last function noted above is
grouped in to a logical link control (LLC) layer. The functions in the first three bullet items are treated
as a separate layer, called medium access control (MAC).
The separation is done for the following reasons:
➢ The logic and mechanism required to manage access to a shared-access medium is not found
in the conventional layer-2 data link control.
➢ For the same LLC, different MAC options may be provided.
LAN TOPOLOGIES
The common topologies for LANs are bus, tree, ring, and star. The bus is a special case of the tree,
with only one trunk and no branches.
Bus and Tree Topologies
Bus and Tree topologies are characterised by the use of a multi-point medium. For the bus all
stations attach, through appropriate hardware interfaces known as a Tap, directly to a linear
transmission medium, or bus. Full-duplex operation between the station and the tap permits data to
be transmitted onto the bus and received from the bus. A transmission from any station propagates
throughout the length of the medium in both directions and can be received (heard) by all other
stations. At each end of the bus is a terminator, to avoid reflection of signals.
Tap Flow of data
TerminatingResistance

The tree topology is a generalisation of the bus topology. The transmission medium is a branched
cable with no closed loops. The tree layout begins at a point known as the head-end, where one or more
cable start, and each of these may have branches. The branches in turn may have additional branches.
Transmission from any station propagates throughout the medium and can be received (heard) by all
other stations.
Ring Topology
In the ring topology, the network consists of a set of repeaters joined by point-to point links in a closed
loop. The repeater is a comparatively simple device, capable of receiving data on one link and
transmitting them, bit by bit, on the other link as quickly as they are received, with no buffering at the
repeater. The links are unidirectional, i.e. data is transmitted in one direction (clockwise or counter-
clockwise).
Each station is attached to the network at a repeater and can transmit data onto the network through
that repeater.
Ring
Star Topology
In the Star type topology, each station is directly connected to a common central node. Typically, each
station attaches to a central node, referred to as the star coupler, via two point-to point links, one for
transmission in each direction.
In general, there are two alternatives for the operation of the central node:
• One method is for the central node to operate in a broadcast fashion. The transmission of a
frame from one station to the Central Node is retransmitted in all of the outgoing links. In this case,
although the arrangement is physically a star, it is logically a bus; a transmission from any station is
received by all other stations, and only one station at a time may transmit (successfully).
• Another method is for the central node to act as a frame switching device. An incoming frame
is buffered in the node and then retransmitted on an outgoing link to the destination station.
Central Hub,Switch/ Repeater

MEDIUM ACCESS CONTROL
All LANs consist of a collection of devices that have to share the network’s transmission capacity.
Some means of controlling access to the transmission medium is needed to provide for an orderly and
efficient use of that capacity. This is the function of medium access control (MAC) protocol.
The MAC layer receives a block of data from the LLC layer and is responsible for performing functions
related to medium access and for transmitting the data. MAC implements these functions, by making
use of protocol data unit at its layer; in this case, the PDU is referred to as a MAC frame.
In general, the fields of this frame are:
➢ MAC control: This field contains any protocol control information needed for the functioning
of the MAC protocol. For example, a priority level could be indicated here.
➢ Destination MAC Address: The destination physical attachment points on the LAN for this
frame.
➢ Source MAC address: The source physical attachment points on the LAN for this frame.
➢ LLC: The LLC Data from the next higher layer.
➢ CRC: The cyclic redundancy check field (also known as the frame check sequence, FCS, field).
This is an error-detecting code, as we have seen in HDLC and other data link control protocols
MAC
Frame
Generic MAC Frame format.
In most of the data link control protocols, the data link protocol entity is responsible not only for
detecting errors using the CRC, but for recovering from those errors by re-transmitting damaged
frames. In the LAN protocol architecture, these two functions are split between the MAC and LLC
layers. The MAC layer is responsible for detecting errors and discarding any frames that are in error.
The LLC layer optionally keeps track of which frames have been successfully received and retransmits
unsuccessful frames.
LOGICAL LINK CONTROL
LLC is concerned with the transmission of a link-level protocol data unit (PDU) between two stations,
without the necessity of an intermediate switching node. LLC has two characteristics not shared by
most other link control protocols:
It must support the multi-access, shared-medium nature of the link.
It is relieved of some details of link access by the MAC layer.
BASIC NETWORK COMPONENTS
There are a number of components which are used to build networks. An understanding of these is
essential in order to support networks.
MAC
control
Destination
MAC
Source
MAC
LLC PDU CRC

Network Adapter Cards
A network adapter card plugs into the workstation, providing the connection to the network. Adapter
cards come from many different manufacturers, and support a wide variety of cable media and bus
types such as - ISA, MCA, EISA, PCI, PCMCIA.
New cards are software configurable, using a software programs to configure the resources used by
the card. Other cards are PNP (plug and Play), which automatically configure their resources when
installed in the computer, simplifying the installation. With an operating system like Windows 95,
auto-detection of new hardware makes network connections simple and quick.
Cabling
Cables are used to interconnect computers and network components together. There are 3 main cable
types used today:
twisted pair
coaxial
fibre optic
The choice of cable depends upon a number of factors like:
cost
distance
number of computers involved
speed
bandwidth i.e., how fast data is to be transferred
REPEATERS
Repeaters extend the network segments. They amplify the incoming signal received from one segment
and send it on to all other attached segments. This allows the distance limitations of network cabling
to be extended. It does not give any more bandwidth or allow to transmit data faster.
Repeaters also allow isolation of segments in the event of failures or fault conditions. A repeater works
at the Physical Layer by simply repeating all data from one segment to another.
Summary of Repeater features:
increases traffic on segments

have distance limitations
limitations on the number of repeaters that can be used
propagate errors in the network
cannot be administered or controlled via remote access
cannot loop back to itself (must be unique single paths)
no traffic isolation or filtering is possible
BRIDGES
Bridges interconnect Ethernet segments. Most bridges today support filtering and forwarding, as well
as Spanning Tree Algorithm. The IEEE 802.1D specification is the standard for bridges.
During initialisation, the bridge learns about the network and the routes. Packets are passed onto
other network segments based on the MAC layer. Each time the bridge is presented with a frame, the
source address is stored. The bridge builds up a table which identifies the segment to which the device
is located on. This internal table is then used to determine which segment incoming frames should be
forwarded to.
The diagram above shows two separate network segments connected via a bridge. Note that each
segment must have a unique network address number in order for the bridge to be able to forward
packets from one segment to the other.
Bridges work at the Media Access Control sub-layer of the Data Link layer of the OSI model.
Summary of Bridge features:
operate at the MAC layer (layer 2 of the OSI model)
can reduce traffic on other segments
broadcasts are forwarded to every segment
most allow remote access and configuration
often SNMP (Simple Network Management Protocol) enabled
loops can be used (redundant paths) if using spanning tree algorithm
small delays may be introduced
fault tolerant by isolating fault segments and reconfiguring paths in the event of failure
not efficient with complex networks
redundant paths to other networks are not used (would be useful if the major path being used
was overloaded)
shortest path is not always chosen by the spanning tree algorithm
ROUTERS
In an environment consisting of several network segments with differing protocols and architectures,
a bridge may not be adequate for ensuring fast communication among all of the segments. A network
this complex needs a device which not only knows the address of each segment, but also determine
the best path for sending data and filtering broadcast traffic to the local segment. Such a device is
called a router.
Routers work at the Network layer of the OSI model. This means they can switch and route packets
across multiple networks. They do this by exchanging protocol-specific information between separate
networks. Routers read complex network addressing information in the packet and, because they
function at a higher layer in the OSI model than bridges, they have access to additional information.
Routers can provide the following functions of a bridge:

Filtering and isolating traffic
Connecting network segments
Routers have access to more information in the packet than bridges, and use this information to
improve packet deliveries. Routers are used in complex network situation because they provide better
traffic management than bridges and do not pass broadcast traffic. Routers can share status and
routing information with one another and use this information to bypass slow or malfunctioning
connections.
How Routers Work
The routing table found in routes contain network addresses. However, host addresses may be kept
depending on the protocol the network is running. A router uses a table to determine the destination
address for incoming data. The table lists the following information:
All known network addresses
How to connect to other networks
The possible path between those routers
The cost of sending data over those paths
The router selects the best route for the data based on cost and available paths.
Summary of Router features:
use dynamic routing
operate at the protocol level
remote administration and configuration via SNMP
support complex networks
the more filtering done, the lower the performance
provides security
segment the networks logically
broadcast storms can be isolated
often provide bridge functions also
more complex routing protocols used (such as RIP, IGRP, OSPF)
HUBS & Switches
There are many types of hubs. Passive hubs are simple splitters or combiners that group workstations
into a single segment, whereas active hubs include a repeater function and are thus capable of
supporting many more connections.
Nowadays, with the advent of 10BaseT, hub concentrators are being very popular. These are very
sophisticated and offer significant features which make them radically different from the older hubs
which were available during the 1980's. These 10BaseT hubs provide each client with exclusive access
to the full bandwidth, unlike bus networks where the bandwidth is shared. Each workstation plugs
into a separate port, which runs at 10 Mbps and is for the exclusive use of that workstation, thus there
is no contention to worry about like in Ethernet. In standard Ethernet, all stations are connected to the
same network segment in bus configuration. Traffic on the bus is controlled using CSMA (Carrier
Sense Multiple Access) protocol, and all stations share the available bandwidth.

10BaseT Hubs dedicate the entire bandwidth to each port (workstation). The W/S attach to the Hub
using UTP. The Hub provides a number of ports, which are logically combined using a single
backplane, which often runs at a much higher data rate than that of the ports.
Ports can also be buffered, to allow packets to be held in case the hub or port is busy. And, because
each workstation has its own port, it does not contend with other workstations for access, having the
entire bandwidth available for its exclusive use.
The ports on a hub all appear as one Ethernet segment. In addition, hubs can be stacked or cascaded
(using master/ slave configurations) together, to add more ports per segment. As hubs do not count
as repeaters, this is a better solution for adding more workstations than the use of a repeater.
Hub options also include an SNMP (Simple Network Management Protocol) agent. This allows the
use of network management software to remotely administer and configure the hub.
The advantages of the newer 10 Base hubs are:
Each port has exclusive access to its bandwidth (no CSMA/ CD)
Hubs may be cascaded to add additional ports
SNMP managed hubs offer good management tools and statistics
Utilise existing cabling and other network components
Becoming a low-cost solution
WIRELESS LAN
A wireless local area network (LAN) utilizes radio frequency (RF) as an alternative for a wired LAN.
Wireless LANs transmit and receive data over the air, without the use of any cable, combining the
benefits of data connectivity and user mobility.
Need for Wireless LAN
The widespread reliance on networking in business and the explosive growth of the Internet reveal
the benefits of shared data and shared resources. With wireless LANs, users can access shared
information and resources without looking for a place to plug in, and network managers can set up
networks without installing or moving wires. Wireless LANs provide all the functionality of wired
LANs with the following benefits:
Mobility: Wireless LANs can provide users with access to real-time information and resources
anywhere in their organization through designated access points. This freedom to "roam" increases
employee productivity as they move throughout the building.
Installation Speed and Simplicity: Installing a wireless LAN system can be fast and easy and
eliminates the need to pull cable through walls and ceilings.
Installation flexibility: Wireless technology allows the network to go where wires cannot go.
Scalability: Configurations for wireless LANs are easily changed and range from peer-to-peer
networks suitable for a small number of users to full infrastructure networks of thousands of users
that enable roaming over a broad area. Adding a user to the network is as simple as equipping a PC
or laptop with a wireless LAN adapter card or USB device.
How do Wireless LANs Work?
Wireless LANs use radio airwaves to communicate information from one point to another without
relying on any physical connection. Radio waves are often referred to as radio carriers because they

simply perform the function of delivering energy to a remote receiver. The data being transmitted is
superimposed (modulated) on the radio carrier so that it can be accurately extracted at the receiving
end. In a typical wireless LAN configuration, a transmitter/receiver device, called an access point
(AP), connects to the wired network from a fixed location using standard cabling. The access point
serves as a communications "hub" that receives, buffers, and transmits data between the wireless
clients and the wired LAN. A single access point can support a small group of users and can function
within a range of less than one hundred to several hundred feet. The access point (or antenna attached
to the access point) is usually mounted high but may be mounted essentially anywhere that is practical
as long as the desired radio coverage is obtained. End users access the wireless LAN through
wireless LAN adapters. These are mostly implemented as PC cards in notebook computers,
PCI cards in desktop computers or as USB devices. Wireless LAN adapters provide an
interface between the client network operating system (NOS) and the airwaves via an antenna

IPV4 ADDRESSING
INTRODUCTION
Internet Protocol version 4 (IPv4) is the fourth revision in the development of the Internet Protocol
(IP) and the first version of the protocol to be widely deployed. Together with IPv6, it is at the core of
standards-based internetworking methods of the Internet. As of 2012 IPv4 is still the most widely
deployed Internet Layer protocol. IPv4 is described in IETF publication RFC 791 (September 1981).
IPv4 is a connectionless protocol for use on packet-switched Link Layer networks (e.g., Ethernet). It
operates on a best effort delivery model; in that it does not guarantee delivery, nor does it assure
proper sequencing or avoidance of duplicate delivery. These aspects, including data integrity, are
addressed by an upper layer transport protocol, such as the Transmission Control Protocol (TCP).
IPv4 uses 32-bit (four-byte) addresses, which limits the address space to 4.3 billion (232) addresses.
Addresses were assigned to users, and the number of unassigned addresses decreased. IPv4 address
exhaustion occurred on February 3, 2011. It had been significantly delayed by address changes such
as classful network design, Classless Inter-Domain Routing, and network address translation (NAT).
Objective
An IP Address and its usage
IPv4 Addressing Scheme
o Classful and Classless Addressing Scheme
o No of Networks / Host per class
o IPv4 Address Pattern
o Characteristics of Classes
o Network and Broadcast Addresses
Subnetting
o Identifying Network Address
VLSM – Variable Length Subnet Mask
CIDR – Classless Inter Domain Routing
To differentiate between Public and Private IP address
IPv4 Address
Each host on a TCP/IP network is uniquely identified at the IP layer with an address. This is called
an IP address. An Internet Protocol (IP) address specifies the location of a host or client on the Internet.
The IP address is also known as Protocol address. It’s a logical address.
The IPv4 address is 32 bits long. From the machine’s perspective, an address may look like
11001010000011100100000000000001. But for human understanding the 32 bits of IP address are
divided into 4 bytes of 8 binary digits and each binary byte is converted into decimal and is separated
by a dot hence also known as Dotted Decimal Notation. As human beings, we see an IP address like
202.14.64.1
In decimal the address range is 0.0.0.0 to 255.255.255.255. An IP address is having two parts: Network
ID or Network Part and Host ID or Host Part. It is of the form <networkID, hosted>
IPv4 Addressing Scheme
Classful
Classless

CLASSFUL ADDRESSING SCHEME:
This was the original addressing scheme in which IPv4 address space was structured into five classes
(A, B, C, D and E). The value of first octet of an IP address determines the class of network to which
it belongs in classful addressing scheme.
A, B & C classes are used to represent host and network address.
Class D is a special type of address used for multicasting.
Number of Networks / Hosts in Class A, B, and C
CLASS NO OF NETWORKS NO OF HOSTS / NETWORK
A 126 16,777,214
B 16,384 65,534
C 2,097,152 254
Class D Address
• These are special addresses 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
Class E Address
• These are reserved for future purposes.
IPv4 Address Bit Pattern
Class Identifier: These are the few initial bits which determine the class of an IP
address. This is turn indicates how many bits are defining network and host.
Subnet Mask: This is the mask which helps in determining the number of bits for
network. In other words, it helps in determining network ID of an address.
Network Address: Network Address is an address of the network. In network
address,all host bits are set to 0. It is similar to STD code in BSNL landline numbers.
Host Address: Host address is an address assigned to an interface of a node.
Network

8 - Bits 8 - Bits 8 - Bits 8 -
Class 0 0 0 0 0 0 0 0 1 1 1 1 1 1 0 - 127
Class 1 0 0 0 0 0 0 1 0 1 1 1 1 1 128 - 191
Class 1 1 0 0 0 0 0 1 1 0 1 1 1 1 192 - 223
Class 1 1 1 0 0 0 0 1 1 1 0 1 1 1 224 - 239
Class E 1 1 1 1 0 0 0 1 1 1 1 1 1 1 240 - 255
Characteristics of classes
ATTRIBUTE CLASS A CLASS B CLASS C CLASS D CLASS E
Class Identifier
0 10 110 1110 1111
Addresses
begins with
1 to 126 128 to 191 192 to 223 224 to 239 240 to 254
Natural or
Default Mask
/8 or
255.0.0.0
/16 or
255.255.0.0
/24 or
255.255.255.0
- -
Network Part /
HostPart
N H H H N N H H N N N H
- -
8
bits
8
bits
8
bits
8
bits
8
bits
8
bits
8
bits
8
bits
8
bits
8
bits
8
bits
8
bits
In Class A, Network ID 0 is not used, and 127 is reserved for loopback.
Network and Broadcast Address
Network Address: The network address is the first address in a range of IP addresses and is used to
communicate with all network devices on a particular network. The network address contains zeroes
in the host portion of the IP address.
Example Network Address
The network address in a range of IP addresses always contains all zeroes in the host portion of the

address as shown below:
192 . 168 . 1 . 0
11000000 10001010 00000001 00000000
The network address is important to network equipment, to routers and to routing.
Network addresses are used to represent destination networks in routing tables.
Broadcast Address: A broadcast address is the last address in a range of IP addresses and allows
information to be sent to all machines on a given subnet rather thana specific machine. The broadcast
address contains ones in the host portion of the IP address.
Example Broadcast Address
The broadcast address in a range of IP addresses always contains all ones in the host portion of the
address as shown below:
192 . 168 . 1 . 255
11000000 10001010 00000001 11111111
Network ID – 203.251.7.00000000 => 203.251.7.0
Broadcast ID – 203.251.7.11111111 =>203.251.7.255
203.251.7.0
CLASSLESS ADDRESSING SCHEME
In classless addressing scheme, classful networks are sub netted or super netted and their default
subnet mask are changed, thereby just by analyzing the class of address
by analysing initial few bits will not help in determining the network ID and for this subnet mask is
must.
Subnetting
Chopping up of a network into a number of smaller networks is called subnetting. Subnetting an IP
Network can be done for a variety of reasons, including organization, use of different physical media
(such as Ethernet, FDDI, WAN, etc.), preservation of address space, and security.
It allows to assign some of the bits, normally used by the host portion of the address, to the network
portion of the address. The format of sub netted IP address would be <network number, subnet
number, host number>. It allows efficient use of full network address.
Subnet is a real network under a network. Any of the classes can be sub netted. The most common
reason is to control network traffic.
203.251.7.255

SUBNETTING USING 1 BIT
Depending upon number of subnets to be carved out of given network, no of bits from host part can
be used for creating these subnets. Example, 1 bit can create 2 subnets, 2 bits for 4 subnet and so on.
Example: Subnetting using 1 bit can be performed in order to divide a network into 2 equal sub-
networks
0001100.10110011.11110000.11001000 140.179.240.200 Class B IP Address
11111111.11111111.00000000.00000000 255.255. 0. 0 Default Class B S/N Mask
----------------------------------------------------------------------
10001100.10110011.00000000.00000000 140.179.0.0 Network Address
VLSM: Variable Length Subnet Mask
Subnetting creates subnets with equal number of hosts, in a network. The number of bits sub netted
i.e.; the length of subnet mask will be same for all the subnets. To co-op with the variable number of
hosts in subnets, in a network, number sub netted bits i.e., the length of subnet mask for the subnets
will also vary. The method of achieving subnetting, with variable length of subnet mask, is known as
Variable Length Subnet Mask.
CIDR: Classless Inter Domain Routing
This is pronounced as – cider. It is also known by the name super netting. It is defined in RFC 1519. It
helps in reducing number of route table entries.
Example: Following networks can be represented as single network.
i. 192.168.0.0/24
ii. 192.168.1.0/24
iii. 192.168.2.0/24
iv. 192.168.3.0/24
Public and Private IP Addresses
On the basis of usage of IP address in networks it can be classified as
Public IP Addresses
These are the address spaces that are used in Public Networks like Internet.

Private IP Addresses
These are used in Private Networks like LAN.
PRIVATE SUBNETS
There are three IP network addresses reserved for private networks. These can be used by anyone for
setting up their internal IP networks. These are equivalent to intercom facility which is setup in a
colony or in apartment. These address blocks are:
10.0.0.0/8
o 24-bit block
o Complete class-A network number
172.16.0.0/12
o 172.0001/0000.0.0-172.0001/1111.255.255
o 20-bit block
o Set of 16 contiguous class-B network numbers
192.168.0.0/16
o 16-bit block
o Set of 256 contiguous class-C network numbers
SUMMARY
IPv4 address is a 32-bit number which is used to identify network devices on the network. Since, the
complete IPv4 address space is finite number i.e., 4.38 billion addresses out of which few hundred
million addresses are usable for Internet; therefore, it is vital to efficiently manage this resource for
proper functioning of network and Internet. Understanding the addressing concepts helps in building
the network and provisioning of addresses to various network components. This has been done with
Subnetting, VLSM and to aggregate the routes CIDR is used

IPV6 BASICS
INTRODUCTION
Internet Protocol version 6 (IPv6) is the sixth revision in the development of the Internet Protocol (IP)
and the second version of the protocol to be widely deployed. Together with IPv4, it is at the core of
standards-based internetworking methods of the Internet.
The current version of IP - IPv4 has not changed substantially since RFC 791, which was published in
1981. IPv4 has proven to be robust, easily implemented, and interoperable. It has stood up to the test
of scaling an internetwork to a global utility the size of today’s Internet. This is a tribute to its initial
design.
However, the initial design of IPv4 did not anticipate the areas like growth of internet, need for
simpler configuration, security consideration, support for prioritized and real-time delivery of data
etc.
OBJECTIVE
➢ Limitations of IPv4
➢ Features of IPv6
LIMITATIONS OF IPv4:
ADDRESSING PROBLEM
Although the 32-bit address space of IPv4 allows for 4.38 billion addresses, previous and current
allocation practices limit the number of public IPv4 addresses to a few hundred million. As a result,
public IPv4 addresses have become relatively scarce, forcing many users and some organizations to
use a NAT (Network Address Translation) to map a single public IPv4 address to multiple private
IPv4 addresses.
Additionally, the rising prominence of Internet-connected devices and appliances ensures that the
public IPv4 address space will eventually be depleted.
ROUTING CRISES
Initially, IPv4 addressing scheme was following classful addressing. However, with the expansion of
Internet and re-allocation of IPv4 address space, this classful addressing form lost its original shape
and transformed into classless addressing by opting for options like subnetting and VLSM. This
resulted in loss of aggregation of routes and routing entries have increased tremendously resulting in
routing crises for the router for routing the traffic.
END TO END PROBLEM
As current IPv4 address space provides only few hundred million public addresses, which are
insufficient for fulfilling the need of hosts in the Internet world. In order to overcome this limitation,
with the help of NAT single global address is being mapped with private address space. Although
NATs promote reuse of the private address space, they violate the fundamental design principle of
the original Internet that all nodes have a unique, globally reachable address, preventing true end-to-
end connectivity for all types of networking applications.

SECURITY
Private communication over a public medium such as the Internet requires cryptographic services
that protect the data being sent from being viewed or modified in transit. Although a standard now
exists for providing security for IPv4 packets (known as Internet Protocol security, or IPsec), this
standard is optional for IPv4 and additional security solutions, some of which are proprietary, are
prevalent.
MOBILITY
The problem of mobility for IPv4 was first addressed in a standard track specification, RFC 2002, “IP
Mobility Support,” in 1996. But this mobility is limited in true sense.
PERFORMANCE AND COST
The performance of IPv4 network will deteriorate if the infrastructure is not upgraded with time to
match the traffic requirement which is increasing with application as well as user base along with
routing entries because of increasing network complexity. This also involves cost in terms of trained
man-power to maintain it. Also, it requires efforts for configuring services like NAT which is mainly
because of scarcity of IPv4 resource.
FEATURES OF IPv6
LARGE ADDRESS SPACE
IPv6 has 128-bit (16-byte) addresses. Although 128 bits can express over 3.4 × 1038 possible
combinations, the large address space of IPv6 has been designed to allow for multiple levels of
subnetting and address allocation, from the Internet backbone to the individual subnets within an
organization.
Even with all of the addresses currently assigned for use by hosts, plenty of addresses are available
for future use. With a much larger number of available addresses, address-conservation techniques,
such as the deployment of NATs, are no longer necessary.
GLOBAL REACHABILITY
With IPv4 NATs, there is a technical barrier for applications that rely on listening or peer-based
connectivity because of the need for the communicating peers to discover and advertise their public
IPv4 addresses and ports. With IPv6, NATs are no longer necessary to conserve public address space,
and the problems associated with mapping addresses and ports disappear for developers of
applications and gateways. More importantly, end-to-end communication is restored between hosts
on the Internet by using addresses in packets that do not change in transit. This functional restoration
has immense value when one considers the emergence of peer-to-peer telephony, video, and other
real-time collaboration technologies for personal communications etc. By restoring global addressing
and end-to-end connectivity, IPv6 has no barrier to new applications that are based on ad hoc
connectivity and peer-based communication.
SCOPED ADDRESSES AND ADDRESS SELECTION
Unlike IPv4 addresses, IPv6 addresses have a scope, or a defined area of the network over which they
are unique and relevant. For example, IPv6 has a global address that is equivalent to the IPv4 public
address and a unique local address that is roughly equivalent to the IPv4 private address. Typical
IPv4 routers do not distinguish a public address from a private address and will forward a privately
addressed packet on the Internet. An IPv6 router, on the other hand, is aware of the scope of IPv6

addresses and will never forward a packet over an interface that does not have the correct scope.
There are different types of IPv6 addresses with different scopes. When multiple IPv6 addresses are
returned in a DNS name query, the sending node must be able to distinguish their types and, when
initiating communication, use a pair (source address and destination address) that is matched in scope
and that is the most appropriate pair to use. For example, for a source and a destination that have
been assigned both global (public) and link-local addresses, a sending IPv6 host would never use a
global destination with a link-local source. IPv6 sending hosts include the address selection logic that
is needed to decide which pair of addresses to use in communication. Moreover, the address selection
rules are configurable. This allows you to configure multiple addressing infrastructures within an
organization. Regardless of how many types of addressing infrastructures are in place, the sending
host always chooses the “best” set of addresses. In comparison, IPv4 nodes have no awareness of
address types and can send traffic to a public address from a private address. The benefit of scoped
addresses is that by using the set of addresses of the smallest scope, your traffic does not travel beyond
the scope for the address, exposing your network traffic to fewer possible malicious hosts.
NEW HEADER FORMAT
The IPv6 header has a new format that is designed to minimize header processing. This is achieved
by moving both nonessential and optional fields to extension headers that are placed after the IPv6
header. The streamlined IPv6 header is more efficiently processed at intermediate routers.
IPv4 headers and IPv6 headers are not interoperable. IPv6 is not a superset of functionality that is
backward compatible with IPv4. A host or router must use an implementation of both IPv4 and IPv6
to recognize and process both header formats. The new default IPv6 header is only twice the size of
the default IPv4 header, even though the number of bits in IPv6 addresses is four times larger than
IPv4 addresses.
STATELESS AND STATEFUL ADDRESS CONFIGURATION
To simplify host configuration, IPv6 supports both stateful address configuration (such as address
configuration in the presence of a DHCP for IPv6) and stateless address configuration (such as address
configuration in the absence of a DHCPv6 server).
With stateless address configuration, hosts on a link automatically configure themselves with IPv6
addresses for the link (called link-local addresses), with IPv6 transition addresses, and with addresses
derived from prefixes advertised by local routers.
IPSEC HEADER SUPPORT REQUIRED
Support for the IPsec headers are an IPv6 protocol suite requirement. This requirement provides a
standards-based solution for network protection needs and promotes interoperability between
different IPv6 implementations. IPsec consists of two types of extension headers and a protocol to
negotiate security settings. The Authentication header (AH) provides data integrity, data
authentication, and replay protection for the entire IPv6 packet (excluding fields in the IPv6 header
that must change in transit). The Encapsulating Security Payload (ESP) header and trailer provide
data integrity, data authentication, data confidentiality, and replay protection for the ESP-
encapsulated payload.
BETTER SUPPORT FOR PRIORITIZED DELIVERY
New fields in the IPv6 header define how traffic is handled and identified. Traffic is prioritized using
a Traffic Class field, which specifies a DSCP value just like IPv4. A Flow Label field in the IPv6 header
allows routers to identify and provide special handling for packets that belong to a flow (a series of
packets between a source and destination). Because the traffic is identified in the IPv6 header, support

for prioritized delivery can be achieved even when the packet payload is encrypted with IPsec and
ESP.
NEW PROTOCOL FOR NEIGHBORING NODE INTERACTION
The Neighbour Discovery protocol for IPv6 is a series of Internet Control Message Protocol for IPv6
(ICMPv6) messages that manages the interaction of neighbouring nodes (nodes on the same link).
Neighbour Discovery replaces and extends the Address Resolution Protocol (ARP) (broadcast-based),
ICMPv4 Router Discovery, and ICMPv4 Redirect messages with efficient multicast and unicast
neighbour Discovery messages.
EXTENSIBILITY
IPv6 can easily be extended for new features by adding extension headers after the IPv6 header.
Unlike options in the IPv4 header, which can support only 40 bytes of options, the size of IPv6
extension headers is constrained only by the size of the IPv6 packet.
IPV6 HAS MORE EFFICIENT FORWARDING
IPv6 is a streamlined version of IPv4. Excluding prioritized delivery traffic, IPv6 has fewer fields to
process and fewer decisions to make in forwarding an IPv6 packet. Unlike IPv4, the IPv6 header is a
fixed size (40 bytes), which allows routers to process IPv6 packets faster. Additionally, the hierarchical
and summarizable addressing structure of IPv6 global addresses means that there are fewer routes to
analyse in the routing tables of organization and Internet backbone routers. The consequence is traffic
that can be forwarded at higher data rates, resulting in higher performance for tomorrow’s high-
bandwidth applications that use multiple data types.
IPV6 HAS SUPPORT FOR SECURITY AND MOBILITY
IPv6 has been designed to support security (IPsec) (AH and ESP header support required) and
mobility (Mobile IPv6) (optional). Although one could argue that these features are available for IPv4,
they are available on IPv4 as extensions, and therefore they have architectural or connectivity
limitations that might not have been present if they had been part of the original IPv4 design. It is
always better to design features in rather than bolt them on. The result of designing IPv6 with security
and mobility in mind is an implementation that is a defined standard, has fewer limitations, and is
more robust and scalable to handle the current and future communication needs of the users of the
Internet. The business benefit of requiring support for IPsec and using a single, global address space
is that IPv6 can protect packets from end to end across the entire IPv6 Internet. Unlike IPsec on the
IPv4 Internet, which must be modified and has limited functionality when the endpoints are behind
NATs, IPsec on the IPv6 Internet is fully functional between any two endpoints.
SUMMARY
There are many reasons for IPv6 supports and there is also need to migrate from current version of
Internet IPv4 to IPv6 for availing additional benefits of Internet. However, for quite some time, things
will move in parallel and smooth transition will be in benefit for the Internet world. Therefore, we
will see IPv4 and IPv6 simultaneously being used by the Internet users, and the service provider. Also,
the application that will be developed during this phase will also keep in mind the requirement of
IPv4 and IPv6.

OSI MODEL
INTRODUCTION
The OSI is the reference model which acted as reference theoretical model for developing a working
model of Internet in the form of TCP/IP protocol suite. Established in 1947, the International
Standards Organization (ISO) is a multinational body dedicated to worldwide agreement on
international standards. An ISO standard that covers all aspects of network communication is the
Open Systems Interconnection (OSI) model (ISO/IEC 7498-1).
An open system is a model that allows any two different systems to communicate regardless of their
underlying architecture. Vendor-specific protocols close off communication between unrelated
systems. The purpose of the OSI model is to open communication between different systems without
requiring changes to the logic of the underlying hardware and software. The OSI model is not a
protocol: it is a model for understanding and designing a network architecture that is flexible, robust
and interoperable.
OBJECTIVE
ISO Model
Layered Architecture
Layers of OSI Model
ISO MODEL
The Open Systems Interconnection model is a layered framework for the design of network systems
that allows for communication across all types of computer systems. It consists of seven separate but
related layers, each of which defines a segment of the process of moving information across a network.
Understanding the fundamentals of the OSI model provides a solid basis for exploration of data
communication.
LAYERED ARCHITECTURE
The OSI model is built of seven ordered layers: Physical (layer 1), Data link (layer 2), Network (layer
3), Transport (layer 4), Session (layer 5), Presentation (layer 6), and Application (layer 7).
The Control is passed from one layer to the next, starting at the application layer in one station, and
proceeding to the bottom layer, over the channel to the next station and back up the hierarchy. During
the process data is encapsulated from the higher layer to the lower layer and reverse is performed at
the other end.
LAYERS OF OSI MODEL
In OSI reference model there seven layers of protocols. Each layer provides services to the layer above
it. There are in all seven layers of in OSI. They are:
1. Physical Layer: It is the lower most layer of the OSI reference model. It is layer which is responsible
for direct interaction of the OSI model with hardware. The hardware provides service to the physical
layer and it provides service to the datalink layer.
The physical layer defines electrical and physical specifications for devices. In particular, it defines
the relationship between a device and a transmission medium, such as a copper or fibre optical cable.

This includes the layout of pins, voltages, line impedance, cable specifications, signal timing, hubs,
repeaters, network adapters, host bus adapters (HBA used in storage area networks) and more.
The major functions and services performed by the physical layer are:
Establishment and termination of a connection to a communications medium.
Participation in the process whereby the communication resources are effectively shared among
multiple users. For example, contention resolution and flow control.
Modulation or conversion between the representation of digital data in user equipment and the
corresponding signals transmitted over a communications channel. These are signals operating over
the physical cabling (such as copper and optical fiber) or over a radio link.
2. Datalink Layer: There may be certain errors which may occur at the physical layer. If possible, these
errors are corrected by the datalink layer. The datalink layer provides the way by which various
entities can transfer the data to the network
Applicaion
Presentation
Session
:
Transport
Network
Data Link
Physical
The data link layer provides the functional and procedural means to transfer data between network
entities and to detect and possibly correct errors that may occur in the physical layer. Originally, this
layer was intended for point-to-point and point-to-multipoint media, characteristic of wide area
media in the telephone system.
Local area network architecture, which included broadcast-capable multi-access media, was
developed independently of the ISO work in IEEE Project 802. IEEE work assumed sublayer-ing and
management functions not required for WAN use. In modern practice, only error detection, not flow
control using sliding window, is present in data link protocols such as Point-to-Point Protocol (PPP),
and, on local area networks, the IEEE 802.2 LLC layer is not used for most protocols on the Ethernet,
and on other local area networks, its flow control and acknowledgment mechanisms are rarely used.
Sliding window flow control and acknowledgment is used at the transport layer by protocols such as
TCP, but is still used in niches where X.25 offers performance advantages.
The ITU-T G.hn standard, which provides high-speed local area networking over existing wires
(power lines, phone lines and coaxial cables), includes a complete data link layer which provides both
error correction and flow control by means of a selective repeat Sliding Window Protocol.

Both WAN and LAN service arrange bits, from the physical layer, into logical sequences called frames.
Not all physical layer bits necessarily go into frames, as some of these bits are purely intended for
physical layer functions. For example, every fifth bit of the FDDI bit stream is not used by the layer.
WAN protocol architecture
Connection-oriented WAN data link protocols, in addition to framing, detect and may correct errors.
They are also capable of controlling the rate of transmission. A WAN data link layer might implement
a sliding window flow control and acknowledgment mechanism to provide reliable delivery of
frames.
LAN architecture
Practical, connectionless LANs began with the pre-IEEE Ethernet specification, which is the ancestor
of IEEE 802.3. This layer manages the interaction of devices with a shared medium, which is the
function of a media access control (MAC) sub-layer. Above this MAC sub-layer is the media-
independent IEEE 802.2 Logical Link Control (LLC) sub-layer, which deals with addressing and
multiplexing on multi-access media.
While IEEE 802.3 is the dominant wired LAN protocol and IEEE 802.11 the wireless LAN protocol,
obsolete MAC layers include Token Ring and FDDI. The MAC sub-layer detects but does not correct
errors.
Network Layer: It does not allow the quality of the service to be degraded that was requested by the
transport layer. It is also responsible for data transfer sequence from source to destination. The
network layer provides the functional and procedural means of transferring variable length data
sequences from a source host on one network to a destination host on a different network (in contrast
to the data link layer which connects hosts within the same network), while maintaining the quality
of service requested by the transport layer. The network layer performs network routing functions,
and might also perform fragmentation and reassembly, and report delivery errors. Routers operate at
this layer, sending data throughout the extended network and making the Internet possible. This is a
logical addressing scheme – values are chosen by the network engineer. The addressing scheme is not
hierarchical.
The network layer may be divided into three sublayers:
1) Subnetwork access – that considers protocols that deal with the interface to networks, such as X.25;
2) Subnetwork-dependent convergence – when it is necessary to bring the level of a transit network up
to the level of networks on either side
3) Subnetwork-independent convergence – handles transfer across multiple networks.
It manages the connectionless transfer of data one hop at a time, from end system to ingress router,
router to router, and from egress router to destination end system. It is not responsible for reliable
delivery to a next hop, but only for the detection of erroneous packets so they may be discarded.
A number of layer-management protocols belong to the network layer. These include routing
protocols, multicast group management, network-layer information and error, and network-layer
address assignment. It is the function of the payload that makes these belong to the network layer,
not the protocol that carries them.
4. Transport Layer: The reliability of the data is ensured by the transport layer. It also retransmits
those data that fail to reach the destination. The transport layer provides transparent transfer of data
between end users, providing reliable data transfer services to the upper layers. The transport layer
controls the reliability of a given link through flow control, segmentation/ desegmentation, and error
control. Some protocols are state- and connection-oriented. This means that the transport layer can
keep track of the segments and retransmit those that fail. The transport layer also provides the
acknowledgement of the successful data transmission and sends the next data if no errors occurred.

Although not developed under the OSI Reference Model and not strictly conforming to the OSI
definition of the transport layer, the Transmission Control Protocol (TCP) and the User Datagram
Protocol (UDP) of the Internet Protocol Suite are commonly categorized as layer-4 protocols within
OSI.
5. Session Layer: The session layer is responsible for creating and terminating the connection.
Management of such a connection is taken care of by the session layer. The session layer controls
the dialogues (connections) between computers. It establishes, manages and terminates the
connections between the local and remote application. It provides for full-duplex, half-
duplex, or simplex operation, and establishes checkpointing, adjournment, termination, and
restart procedures. The OSI model made this layer responsible for graceful close of sessions,
which is a property of the Transmission Control Protocol, and also for session check pointing
and recovery, which is not usually used in the Internet Protocol Suite. The session layer is
commonly implemented explicitly in application environments that use remote procedure
calls. On this level, Inter-Process communication happen (SIGHUP, SIGKILL, End Process,
etc.).
Presentation Layer: This layer is responsible for decoding the context (syntax and semantics) of the
higher-level entities. The presentation layer establishes context between application-layer entities, in
which the higher-layer entities may use different syntax and semantics if the presentation service
provides a mapping between them. If a mapping is available, presentation service data units are
encapsulated into session protocol data units, and passed down the stack.
This layer provides independence from data representation (e.g., encryption) by translating between
application and network formats. The presentation layer transforms data into the form that the
application accepts. This layer formats and encrypts data to be sent across a network. It is sometimes
called the syntax layer. The original presentation structure used the Basic Encoding Rules of Abstract
Syntax Notation One (ASN.1), with capabilities such as converting an EBCDIC-coded text file to an
ASCII-coded file, or serialization of objects and other data structures from and to XML.
7. Application Layer: Whichever software application that implements socket programming will
communicate with this layer. This layer is closest to the user. The application layer is the OSI layer
closest to the end user, which means that both the OSI application layer and the user interact directly
with the software application. This layer interacts with software applications that implement a
communicating component. Such application programs fall outside the scope of the OSI model.
Application-layer functions typically include identifying communication partners, determining
resource availability, and synchronizing communication. When identifying communication partners,
the application layer determines the identity and availability of communication partners for an
application with data to transmit. When determining resource availability, the application layer must
decide whether sufficient network or the requested communication exist. In synchronizing
communication, all communication between applications requires cooperation that is managed by the
application layer.
Some examples of application-layer implementations also include:
On OSI stack:
FTAM File Transfer and Access Management Protocol
X.400 Mail
Common Management Information Protocol (CMIP)
SUMMARY
OSI model is reference model which clearly mentions the independent functions of each layer. This
has resulted in developments in different layered areas irrespective of the functionality in other layers.

TCP/IP MODEL
INTRODUCTION
The Internet protocol suite is the set of communications protocols used for the Internet and similar
networks. Because of most popular protocol stack for wide area networks, it is commonly known as
TCP/IP. The most important protocols are: Transmission Control Protocol (TCP) and Internet
Protocol (IP). These protocols were the first networking protocols defined in this standard.
The TCP/IP model and related protocols are maintained by the Internet Engineering Task Force
(IETF).
OBJECTIVE
a) TCP/IP Model
b) Layers of TCP/IP
c) TCP, UDP, IP header
d) Major TCP/IP Protocols
e) Comparison of OSI and TCP/IP Model
TCP/IP MODEL
The Internet protocol suite is the set of communications protocols used for the Internet and similar
networks, and generally the most popular protocol stack for wide area networks. It is commonly
known as TCP/IP, because of its most important protocols: Transmission Control Protocol (TCP) and
Internet Protocol (IP), which were the first networking protocols defined in this standard.
TCP/IP provides end-to-end connectivity specifying how data should be formatted, addressed,
transmitted, routed and received at the destination. It has four abstraction layers, each with its own
protocols. Each layer is responsible for a set of computer network related tasks. Every layer provides
service to the layer above it.
Key architectural principles
An early architectural document, RFC 1122, emphasizes architectural principles over layering.
End-to-end principle: This principle has evolved over time. Its original expression put the
maintenance of state and overall intelligence at the edges, and assumed the Internet that connected
the edges retained no state and concentrated on speed and simplicity. Real-world needs for firewalls,
network address translators, web content caches and the like have forced changes in this principle.
Robustness Principle: In general, an implementation must be conservative in its sending behaviour,
and liberal in its receiving behaviour. That is, it must be careful to send well-formed datagrams, but
must accept any datagram that it can interpret (e.g., not object to technical errors where the meaning
is still clear). The second part of the principle is means that software on other hosts may contain
deficiencies that make it unwise to exploit legal but obscure protocol features.
LAYERS OF TCP/IP MODEL
TCP/IP model has four abstraction layers, each with its own protocols. From lowest to highest, the
layers are:

1. The link layer (commonly Ethernet) contains communication technologies for a local network.
2. The internet layer (IP) connects local networks, thus establishing internetworking.
3. The transport layer (TCP) handles host-to-host communication.
4. The application layer (for example HTTP) contains all protocols for specific data communications
services on a process-to-process level (for example how a web browser communicates with a web
server).
Functions of Layers
1. Application Layer: This is the topmost layer of the TCP/IP suite. This is responsible for coding of
the packet data. It contains all protocols for specific data communications services on a process-to-
process level. For example, how a web browser communicates with a web server.
2. Transport Layer: This layer monitors end-to-end path selections of the packets. It also provides
service to the application layer. It handles host-to-host communication
3. Internet Layer: This layer is responsible for sending packets through different networks. It connects
local networks, thus establishing internetworking.
4. Link Layer: It is the closest layer to the network hardware. It provides service to Internet layer. The
Link Layer (commonly Ethernet) contains communication technologies for a local network.
Major TCP/IP Protocols
Following table illustrates all the major TCP/IP Internet protocols and associates a layer of the
architecture with each. Application-layer protocols are divided into two groups; first, those use TCP
second use UDP.
LAYER # LAYER PROTOCOLS
1. Data
Protocols defined by underlying networks
2. Physical
3. Network IP, ARP, RARP, ICMP, IGMP
4. Transport
TCP (Reliable & Connection Oriented)
UDP (Unreliable & Connectionless)
5. Application
Protocols Using TCP at Layer 4:
FTP, SMTP, TELNET, HTTP
Protocols Using UDP at Layer 4:
TFTP, SNMP, NFS, DNS
User Service Application
User service applications include the following.
➢ TELENET – provides a remote logon capability
➢ File transfer protocol (FTP) – provides a reliable file transfer capability
➢ Trivial file transfer protocol (TFTP) – provides an unreliable, simple file transfer capability.
➢ Network file system (NFS) – provides remote virtual storage capability.

➢ Simple message transfer protocol (SMTP) – provides electronic mail capability.
Utility Applications
Utility applications include the following.
➢ Simple network management protocol (SNMP) – provides network management information.
➢ Boot protocol (BOOTP) – provides remote loading capability for diskless workstations.
➢ Domain name service (DNS) – provides directory assistance for Internet addresses using local
names.
➢ Address resolution protocol (ARP) – provides a physical address from an IP address.
➢ Reverse address resolution protocol (RARP) – provides an IP address from a physical device
address.
➢ In theory, all application protocols could use either the UDP or the TCP transport protocol.
The reliability requirements of the application dictates, which transport layer protocol is used.
For example, some applications, such as the domain name service (DNS), may either UDP or
TCP. The UDP provides an unreliable, connectionless transport service, while the TCP
provides a reliable, in-sequence, and connection-oriented service. Because the UDP is
unreliable, many of the application layer protocols only use TCP, for example, FTP and
TELNET. For the application layer protocols that do not require a reliable service, they use
only UDP, for example, TFTP, SNMP, VoIP etc.
TCP/IP NETWORK LAYER PROTOCOL
The Internet protocol (IP) receives data directly from the Ethernet and functions on an architectural
level equivalent to the network layer of the OSI reference model. The protocols ARP and RARP receive
data directly from the Ethernet in the same manner as the IP.
IPv4 Header Fields
➢ Version - The version is a binary number that is four bits long. It indicates which version of IP
is being used.
➢ IHL (Internet Header Length) - The IHL simply measures the length of the IP header in 32-bit
words. The minimum header length is five 32-bit words.
➢ Type of Service - This field is for specifying special routing information. This field in particular
relates to Quality-of-Service technologies quite well. Essentially, the
➢ purpose of this 8-bit field is to prioritize datagrams that are waiting to pass through a router.
➢ Total Length - This 16-bit field includes the length of the IP datagram. This length includes the
IP header and also the data itself.
➢ Identification - This is a 16-bit field that acts as a means of organizing chunks of data. If a
message is too large to fit in one data packet, it is split up and all of its child packets are given
the same identification number. This is handy to ensure data is rebuilt on the receiving end
properly.
➢ Flags - This field signifies fragmentation options- such as whether or not fragments are
allowed. The Flags field also has capability to tell the receiving source that more fragments are
on the way, if enabled. This is done with the MF flag, also known as the more fragments flag.

➢ Fragment Offset - This is a 13-bit field that assigns a number value to each fragment. The
receiving computer will then use these numbers to reassemble the data correctly. Obviously,
this is only applicable if fragments are allowed.
➢ Time to Live - This is often known as TTL. It is a field that indicates how many hops a data
packet should go through before it is discarded. When it reaches zero, it is discarded.
➢ Protocol - This 8-bit field indicates which protocol should be used to receive the data. Some of
the more popular protocols such as TCP and UDP are identified by the numbers 6 and 17
respectively.
➢ Header Checksum - This 16-bit field holds a calculated value that is used to verify that the
header is still valid. Each time a packet travels through a router this value is recalculated to
ensure the header is still indeed valid.
➢ Destination IP Address - This 32-bit field holds the IP address of the receiving computer. It is
used to route the packet and to make sure that only the computer with the IP address in this
field obtains the packets.
➢ Source IP Address - This 32-bit field holds the IP address of the sending computer. It is used
to verify correct delivery, and will also be the return address in case an error occurs.
➢ IP Options - This field can hold a fair number of optional settings. These settings are primarily
used for testing and security purposes
➢ Padding - Since the IP options field varies in length depending on the configuration, we need
to have this field set to occupy left over bits. This is because the header needs to be ended after
a 32-bit word: no more, no less.
➢ Data - It is simply the data that is being sent.
TCP Header Field
1. Source port (16 bits) – identifies the sending port
2. Destination port (16 bits) – identifies the receiving port
3. Sequence number (32 bits) – has a dual role: If the SYN flag is set (1), then this is the initial sequence
number. If the SYN flag is clear (0), then this is the accumulated sequence number of the first data
byte of this segment for the current session.
4. Acknowledgment number (32 bits) – if the ACK flag is set then the value of this field is the next
sequence number that the receiver is expecting. This acknowledges receipt of all prior bytes (if any).
The first ACK sent by each end acknowledges the other end's initial sequence number itself, but no
data.
5. Data offset (4 bits) – specifies the size of the TCP header in 32-bit words. The minimum size header
is 5 words and the maximum is 15 words thus giving the minimum size of 20 bytes and maximum of
60 bytes, allowing for up to 40 bytes of options in the header.
6. Reserved (3 bits) – for future use and should be set to zero
7. Flags (9 bits) (aka Control bits) – contains 9 1-bit flags
NS (1 bit) – ECN-nonce concealment protection (added to header by RFC 3540).
CWR (1 bit) – Congestion Window Reduced (CWR) flag is set by the sending host to indicate that
it received a TCP segment with the ECE flag set and had responded in congestion control mechanism
(added to header by RFC 3168).
ECE (1 bit) – ECN-Echo indicates
If the SYN flag is set (1), that the TCP peer is ECN capable.
If the SYN flag is clear (0), that a packet with Congestion Experienced flag in IP header set is received
during normal transmission (added to header by RFC 3168).

URG (1 bit) – indicates that the Urgent pointer field is significant
ACK (1 bit) – indicates that the Acknowledgment field is significant. All packets after the initial
SYN packet sent by the client should have this flag set.
PSH (1 bit) – Push function. Asks to push the buffered data to the receiving application.
RST (1 bit) – Reset the connection
SYN (1 bit) – Synchronize sequence numbers. Only the first packet sent from each end should have
this flag set. Some other flags change meaning based on this flag, and some are only valid for when it
is set, and others when it is clear.
FIN (1 bit) – No more data from sender
8. Window size (16 bits) – the size of the receive window, which specifies the number of bytes (beyond
the sequence number in the acknowledgment field) that the sender of this segment is currently willing
to receive (see Flow control and Window Scaling)
9. Checksum (16 bits) – The 16-bit checksum field is used for error-checking of the header and data
10. Urgent pointer (16 bits) – if the URG flag is set, then this 16-bit field is an offset from the sequence
number indicating the last urgent data byte
11. Options (Variable 0–320 bits, divisible by 32) – The length of this field is determined by the data
offset field. Options have up to three fields: Option-Kind (1 byte), Option-Length (1 byte), Option-
Data (variable).
12. Padding – The TCP header padding is used to ensure that the TCP header ends and data begins
on a 32-bit boundary. The padding is composed of zeros.[6]
UDP Header Field
1. Source port number: This field identifies the sender's port when meaningful and should be assumed
to be the port to reply to if needed. If not used, then it should be zero.
2. Destination port number: This field identifies the receiver's port and is required.
3. Length: A field that specifies the length in bytes of the entire datagram: header and data. The
minimum length is 8 bytes since that's the length of the header. The field size sets a theoretical limit
of 65,535 bytes (8-byte header + 65,527 bytes of data) for a UDP datagram. The practical limit for the
data length which is imposed by the underlying IPv4 protocol is 65,507 bytes (65,535 − 8-byte UDP
header − 20 byte IP header).
4. Checksum: The checksum field is used for error-checking of the header and data. If no checksum is
generated by the transmitter, the field uses the value all-zeros.

NIBOVERVIEW
INTRODUCTION
BSNL has setup NIB to provide world class infrastructure to offer various value-added services to a
broader customer base county-wide that will help to accelerate the Internet revolution in India.
Moreover, the NIB will create a platform, which enables e-governance, e-banking, e-learning, etc. with
the key point of Service Level Agreements & Guarantee in tune with Global standards and customer
expectations.
OBJECTIVE
➢ After reading this unit, you should be able to understand:
➢ Objectives of setting up the NIB network
➢ Various projects under NIB
➢ Equipment deployed under various projects
OBJECTIVES OF NIB
i.) NIB is a mission to build world-class infrastructure that has helped accelerate the Internet
revolution in India.
ii.) It provides a diversified range of Internet access services including support for VPN (Layer-2,
Layer-3 and Dialup and Broadband services)
iii.) It also offers SLA Reports including security, QoS and any to any connectivity.
iv.) Offers fully managed services to customers.
v.) It offers services like bandwidth on demand etc. over the same network.
vi.) The network is capable of on-line measurement and monitoring of network parameters such as
latency, packet loss, jitter and availability so as to support SLAs with customers
vii.) The routers support value added services such as VPNs, Web and content hosting, Voice over IP,
Multicast etc.
viii.) Value Added Services
a. Encryption Services
b. Firewall Services
c. Multicast Services
d. Network Address Translation (NAT) Service that will enable private users to access public
networks
ix.) Messaging Services
x.) Internet Data Centre Services at Metropolitan cities.
xi.) Broad Band Services
a. Broadcast TV using IP Multicasting service
b. Multicast video streaming services
c. Interactive Distant learning using IP multicasting Services
d. Video on demand
e. Interactive gaming service
PROJECT 1– IP / MPLS CORE BACKBONE
1. 100 location Managed IP & MPLS Network

Combinepdf (1)

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to Combinepdf (1)

Similar to Combinepdf (1) (20)

Recently uploaded

Recently uploaded (20)

Combinepdf (1)