descriptive discussion on tcp/ip..!

7/30/2019 Descriptive Discussion On TCP/IP..!

1/65

INTERNET AND TCP/IP

BY CTTC, KOLKATA

INTERNET AND TCP/IP

BY CTTC, KOLKATA

INTERNET AND TCP/IP

BY CTTC, KOLKATA

INTERNET AND TCP/IP

BY CTTC, KOLKATA


2/65

AGENDA

WHAT IS COMPUTER NETWORK

EVOLUTION OF NETWORKS

STANDARDISATION OF NETWORK

OSI REFERENCE MODEL CLASSIFICATION OF NETWORK

NETWORKING COMPONETS

NETWORKING TOPOLOGIES

TCP/IP PROTOCOL


3/65

WHAT IS COMPUTER NETWORK


4/65

A NETWORK IS THE MECHANISM THAT

ENABLES DISTRIBUTED COMPUTERS AND

THEIR USERS TO COMMUNICATE AND

SHARE RESOURCES.


5/65

EVOLUTION OF NETWORKS

NETWORKS ORIGINALLY WERE HIGHLY PROPRIETARY.

CONNECTIVITY SOLUTIONS THAT WERE AN INTEGRAL

PART OF AN EQUALLY PROPRIETARY BUNDLED

COMPUTING SOLUTION. COMPANIES THAT AUTOMATED

THEIR DATA PROCESSING OR ACCOUNTING FUNCTIONS

DURING THE PRIMITIVE DAYS BEFORE PERSONAL

COMPUTERS, HAD TO COMMIT TO A SINGLE VENDOR

FOR A TRUNKEY SOLUTION.


6/65

IN THESE ENVIRONMENTS, THE APPLICATION SOFTWARE

EXECUTED ONLY ON A COMPUTER SUPPORTED BY A

SINGLE OPERATING SYSTEM. THE OPERATING SYSTEM

COULD EXECUTE ONLY WITHIN THE BOUNDARY OF THE

SAME VENDORS HARDWARE PRODUCTS. EVEN THE

USERS TERMINAL AND CONNECTIVITY TO THE

COMPUTER WERE PART OF THE SAME, ONE-VENDOR

INTEGRATED SOLUTION.


7/65

THEN TWO DEVELOPMENTS OCCURRED THAT CHANGEDTHE FUTURE COURSE OF COMPUTING.

FIRST THE PCs BEGAN TO APPEAR. THESE DEVICESWERE INNOVATIVE IN THAT THEY PLACEDCOMPUTATIONAL POWER RIGHT AT THE DESKTOP.

SECOND THE SCIENTIST AT Xerox's PALO ALTORESEARCH CENTER(PARC) BEGAN TO DEVELOPSOMETHING FOR SHARING OF FILES AND DATABETWEEN THEIR INTELLIGENT WORKSTATIONS

THEIR SOLUTION WAS THE ORIGINAL LOCAL AREA

NETWORK (LAN). THEY CALLED IT ETHERNET. IT IS ALSOKNOWN AS PARC ETHERNET OR ETHERNET I.


8/65

THEN THIS ETHERNET WAS DEVELOPED BY THREE

ORGANISATIONS DIGITAL, INTEL AND XEROX AND THIS

ETHERNET BECAME KNOWN AS DIX ETHERNET OR

ETHERNET II.

FURTHER IT WAS DEVELOPED BY IEEE BY THEIRPROJECT 802.

802.3 ETHERNET

802.4 TOKEN RING

802.11 WI-FI LAN

802.16 - WIMAX


9/65

STANDARDISATION OF NETWORK


10/65

THE SUCCESS OF ETHERNET I AND IIDEMONSTRATED THAT THE MARKETPLACEWAS TIRED OF THE PROPRIETARY APPROACHTO BUNDLED NETWORKING AND COMPUTING.

CUSTOMER BEGAN DEMANDING A MORE OPENENVIRONMENT THAT WOULD ENABLE THEM TOBUILD APPLICATIONS FROM MIXED ANDMATCHED PRODUCTS FROM DIFFERENTVENDORS.


11/65


12/65

ISO DEVELOPED THE OPEN SYSTEMS

INTERCONNECTION (OSI) REFERENCE

MODEL TO FACILITATE THE OPEN

INTERCONNECTION OF COMPUTERSYSTEMS. AN OPEN INTERCONNECTION

IS ONE THAT CAN BE SUPPORTED IN A

MULTIVENDOR ENVIRONMENT.


13/65

THE OSI MODEL CATEGORISES THE VARIOUSPROCESSES THAT ARE NEEDED IN ACOMMUNICATION SESSION INTO SEVEN DISTINCTFUNCTIONAL LAYERS.

THE LAYERS ARE ORGANISED BASED ON THENATURAL SEQUENCE OF EVENTS THAT OCCURSDURING A COMMUNICATION SESSION.

BASICALLY LAYERS 1-3 PROVIDE NETWORKACCESS, WHEREAS LAYERS 4-7 ARE DEDICATEDTO THE LOGISTICS OF SUPPORTING END TO ENDCOMMUNICATIONS.


14/65

LAYER 1 PHYSICAL LAYER

THE BOTTOM LAYER IS CALLED THE PHYSICALLAYER AND IS RESPONSIBLE FOR THETRANSMISSION OF THE BIT STREAM. IT

ACCEPTS FRAMES OF DATA FROM LAYER 2

(DATA LINK LAYER) AND TRANSMITS THEIRSTRUCTURE AND CONTENT SERIALLY, ONE BITAT A TIME. IT IS ALSO RESPONSIBLE FOR THERECEPTION OF INCOMING STREAMS OF DATA,ONE BIT AT A TIME. THESE STREAMS ARE THEN

PASSED ON TO THE DATA LINK LAYER FORREFRAMING.


15/65

THIS LAYER, QUITE LITERALLY, SEES ONLY 1s AND0s. IT HAS NO MECHANISM FOR DETERMINING THESIGNIFICANCE OF THE BITS IT TRANSMITS ORRECEIVES. IT IS SOLELY CONCERNED WITH THEPHYSICAL CHARACTERISTICS OF ELECTRICAL

AND/OR OPTICAL SIGNALLING TECHNIQUES. THISINCLUDES THE VOLTAGE OF THE ELECTRICALCURRENT USED TO TRANSPORT THE SIGNAL, THEMEDIA TYPE AND IMPEDENCE CHARACTERISTICS,AND EVEN THE PHYSICAL SHAPE OF THE

CONNECTOR USED TO TERMINATE THE MEDIA.


16/65

LAYER 2 DATA LINK LAYER

THE SECOND LAYER OF OSI MODEL IS CALLED THE DATALINK LAYER. ON THE TRANSMIT SIDE DATA LINK LAYER ISRESPONSIBLE FOR PACKING INSTRUCTIONS, DATA ANDSO FORTH INTO FRAMES. A FRAME IS A STRUCTUREINDIGENOUS TO THE DATA LINK LAYER THAT CONTAINS

ENOUGH INFORMATION TO MAKE SURE THE DATA CANBE SUCCESSFULLY SENT ACROSS A LOCAL AREANETWORK TO ITS DESTINATION. THE DATA LINK LAYERIS ALSO RESPONSIBLE FOR REASSEMBLING ANY BINARYSTREAMS THAT ARE RECEIVED FROM THE PHYSICALLAYER BACK INTO FRAMES. DATA LINK LAYER IS NOT

REALLY REBUILDING A FRAME. RATHER, ITS BUFFERINGTHE INCOMING BITS UNTIL IT HAS A COMPLETE FRAME.


17/65


18/65

LAYER 4 TRANSPORT LAYER

THE TRANSPORT LAYER PROVIDES A SERVICESIMILAR TO THE DATA LINK LAYER IN THAT IT ISRESPONSIBLE FOR THE END TO END INTEGRITYOF TRNSMISSIONS. UNLIKE THE DATA LINK

LAYER, THE TRANSPORT LAYER IS CAPABLE OFPROVIDING THIS FUNCTION BEYOND THELOCAL LAN SEGMENT. IT CAN DETECT PACKETSTHAT ARE DISCARDED BY ROUTERS AND

AUTOMATICALLY GENERATE A RETRANSMIT

REQUEST. ANOTHER SIGNIFICANT FUNCTION OF THE

TRANSPORT LAYER IS THE RESEQUENCING OFPACKETS THAT MAY ARRIVED OUT OF ORDER.


19/65

LAYER 5 SESSION LAYER

THE FIFTH LAYER OF OSI MODEL IS CALLED

SESSION LAYER. THIS LAYER MANAGES THE

FLOW OF COMMUNICATIONS DURING A

CONNECTION BETWEEN TWO COMPUTER

SYSTEMS. THIS FLOW OF COMMUNICATIONS ISKNOWN AS SESSION. IT DETERMINES WHETHER

COMMUNICATIONS CAN BE UNI- OR BI

DIRECTIONAL. IT ALSO ENSURES THAT ONE

REQUEST IS COMPLETED BEFORE A NEW ONEIS ACCEPTED.


20/65

LAYER 6 PRESENTATION LAYER

THE PRESENTATION LAYER IS RESPONSIBLEFOR MANAGING THE WAY DATA IS ENCODED.NOT EVERY COMPUTER SYSTEM USES THESAME DATA-ENCODING SCHEME, AND THE

PRESENTATION LAYER IS RESPONSIBLE FORPROVIDING THE TRANSLATION BETWEENOTHERWISE INCOMPATIBLE DATA-ENCODINGSCHEMES, SUCH AS ASCII AND EBCDIC.


21/65

LAYER 7 APPLICATION LAYER

THE TOP LAYER OF OSI MODEL IS APPLICATIONLAYER. IT PROVIDES INTERFACE BETWEENUSER APPLICATIONS AND THE NETWORKSSERVICES. THIS LAYER CAN BE THOUGHT OF

AS THE REASON FOR INITIATING THECOMMUNICATIONS SESSION. FOR EXAMPLE, ANE-MAIL CLIENT MIGHT GENERATE A REQUESTTO RETRIEVE NEW MESSAGES FROM THE E-MAIL SERVER. THIS CLIENT APPLICATION

AUTOMATICALLY GENERATES A REQUEST TOTHE APPROPRIATE LAYER 7 PROTOCOLS ANDLAUNCHES A COMMUNICATIONS SESSION TOGET THE NEEDED FILES.


22/65

Classification of Networks

Classification by network geography.

Classification by component roles.


23/65

Classification by Network

Geography

Networks are frequently classified according

to the geographical boundaries spanned by

the network itself.

LAN, WAN, and MAN are the basic types ofclassification, of which LAN and WAN are

frequently used.


24/65

Local area network (LAN):

A LAN covers a relatively small area such as a

classroom, school, or a single building.

LANs are inexpensive to install and alsoprovide higher speeds.


Geography


25/65

Local area network


Geography


26/65

Metropolitan area network (MAN):

A MAN spans the distance of a typical

metropolitan city.

The cost of installation and operation is higher. MANs use high-speed connections such as

fiber optics to achieve higher speeds.


Geography


27/65

Metropolitan area network


Geography


28/65

Wide area network (WAN):

WANs span a larger area than a single city.

These use long distance telecommunication

networks for connection, thereby increasingthe cost.

The Internet is a good example of a WAN.


Geography


29/65

Wide area network


Geography


30/65

Classification by Component Roles

Networks can also be classified according to

the roles that the networked computers play

in the networks operation.

Peer-to-peer, server-client-based are thetypes of roles into which networks are

classified.


31/65


Peer-to-peer:

In a peer-to-peer network, all computers are considered

equal.

Each computer controls its own information and is capable

of functioning as either a client or a server depending upon

the requirement.

Peer-to-peer networks are inexpensive and easy to install.

They are popular as home networks and for use in small

companies.


32/65


Peer-to-peer (continued):

Most operating systems come with built-in

peer-to-peer networking capability.

Each peer shares resources and allows othersopen access to them.


33/65


Peer-to-peer (continued):

Peer-to-peer networks become difficult to

manage when more security is added to

resources, since the users control theirsecurity by password-protecting shares.

Shares can be document folders, printers,

peripherals, and any other resource that they

control on their computers.


34/65


Peer-to-peer network


35/65


Server-Client based:

A server-based network offers centralized

control and is designed for secure operations.

In a server-based network, a dedicated servercontrols the network.


36/65


Server-Client based (continued):

A dedicated server is one that services the

network by storing data, applications,

resources, and also provides access toresources required by the client.

These servers can also control the networks

security from one centralized location or share

it with other specially configured servers.


37/65


Server-client basednetwork


38/65

NETWORKING COMPONETS


39/65

Networking Hardware

ComponentsA Network is comprised of a variety of

hardware components:

Internet

Firewall

Transmission Media

Interface Cards

Hubs

Switches

RoutersRouter Router

Switch

(Kolkata office)

Switch

(Siliguri office)

Hub(sales)

Hub(sales)

d


40/65

LAN Transmission Media

Twisted Pair

Coaxial Cable

Woven Metal Shield

Plastic insulating jacket Non-conducting insulator

Central Copper Conduit Plastic Insulating Jacket

Central Copper Conduit

Fiber Optic

Glass or Plastic Fiber Cable

Photodiode Receiver

LED or Laser

Transmitter


41/65

Ethernet Media Types


42/65

Sending and receiving Ethernet frames via a hub

3333 1111

So, what does a hubdo when it receivesinformation?

Remember, a hub isnothing more than a

multiport repeater.

1111 2222

3333 4444

5555


43/65


Hub or


44/65


3333 1111

The hub will flood it out allports except for the

incoming port. Hub is a layer 1 device.

Disadvantage with hubs: Ahub or series of hubs is asingle collision domain.

A collision will occur if anytwo or more devicestransmit at the same timewithin the collision domain.

More on this later.


45/65


1111

Wastedbandwidth

2222 1111

Another disadvantage with hubsis that it take up unnecessary

bandwidth on other links.2222

3333 4444

5555


46/65

Sending and receiving Ethernet frames via a switch

SourceAddress Table

Port Source MAC Add. Port Source MAC Add.

3333 1111

Switches are also known aslearning bridges or learning

switches. A switch has a source address

table in cache (RAM) where itstores source MAC address afterit learns about them.

A switch receives an Ethernetframe it searches the source

address table for the DestinationMAC address.

If it finds a match, it filters theframe by only sending it out thatport.

If there is not a match iffloodsit out all ports.

3333

2222

1111

4444


47/65

No Destination Address in table, Flood

Source Address Table


1 1111

How does it learn source MAC

addresses? First, the switch will see if the SA

(1111) is in its table.

If it is, it resets the timer (more in amoment).

If it is NOT in the table it adds it, withthe port number.

Next, in our scenario, the switch willflood the frame out all other ports,because the DA is not in the sourceaddress table.

3333 1111

1111 3333

44442222


48/65

Destination Address in table, Filter



1 1111 6 3333

Most communications involve

some sort of client-serverrelationship or exchange ofinformation.

Now 3333 sends data back to1111.

The switch sees if it has the SAstored.

It does NOT so it adds it. (Thiswill help next time 1111 sends to3333.)

Next, it checks the DA and in ourcase it can filter the frame, bysending it only out port 1.

1111 3333

1111 3333

2222 4444

D i i Add i bl Fil


49/65

Destination Address in table, Filter



1 1111 6 3333

Now, because both MAC addressesare in the switchs table, anyinformation exchanged between1111 and 3333 can be sent(filtered) out the appropriate port.

What happens when twodevices send to samedestination?

What if this was a hub?

Where is (are) the collisiondomain(s) in this example?

switch

1111

2222

3333

4444

Abbreviated

MAC

addresses

11113333

33331111


50/65

What happens here?


51/65

What happens here?

33331111

3333

1111



1 1111 6 3333

1 2222 1 5555

2222 5555

Collision Domain


52/65

Using Hubs

Layer 1 devices

Inexpensive

In one port, out the others

One collision domain

One broadcast domain


53/65

Using Switches

Layer 2 devices

Layer 2 filtering based on Destination MACaddresses and Source Address Table

One collision domain per port

One broadcast domain across all switches

R t


54/65

Routers

Router

Router Router Router

Routers

Routers use IP addresses to route data between networks.

Routers can be used to connect different network types.

Routers dont forward broadcast packets; broadcast packets are dropped.


55/65

LAN Topologies

BusRing

Hub

Star

A LANs Physical Topology:

A LANs Logical Topology:

Describes how a network is

physically cabled.

Describes the logical pathway

a signal follows as it passes

among the network nodes.


56/65

TCP/IP


57/65

TCP/IP is an industry standard set of protocols developed by the U.S. Department

of Defense Advanced Research Projects Agency (DARPA) in 1969. It maps

TCP/IP protocols to a four-layer conceptual model known as the DARPA model. Itis often compared to the still born OSI Protocol Layers. The four layers of the

DARPA model are:

1.Application,

2.Transport,

3.Internet,

4.Network Interface
http://www.softpanorama.org/Net/osi_protocol_layers.shtmlhttp://www.softpanorama.org/Net/Application_layer/index.shtmlhttp://www.softpanorama.org/Net/Transport_layer/index.shtmlhttp://www.softpanorama.org/Net/Internet_layer/index.shtmlhttp://www.softpanorama.org/Net/Network_interface_layer/ethernet.shtmlhttp://www.softpanorama.org/Net/Network_interface_layer/ethernet.shtmlhttp://www.softpanorama.org/Net/Internet_layer/index.shtmlhttp://www.softpanorama.org/Net/Transport_layer/index.shtmlhttp://www.softpanorama.org/Net/Application_layer/index.shtmlhttp://www.softpanorama.org/Net/osi_protocol_layers.shtml


58/65

Application layerRefers to standard network services like http, ftp, telnet as well as

communication methods used by various application programs

Also defines compatible representationof all data

Transport layerManages the transfer of data by using connection oriented (TCP) and

connectionless (UDP) transport protocolsManages the connections between networked applications

Internet layerManages addressing of packets and delivery of packets between

networks

Fragments packetsso that they can be dealt with by lower level layer

(Network Interface layer Network)Network Interface layer

Delivers data via physical link(Ethernet is the most common link level

protocol )

Provides error detection and packet framing


59/65

TCP/IP functions

Establish a connection between nodes Manage data flow on the network

Handle transmission errors

Terminate connection at the end

TCP is a connection-oriented protocol, meaning that a

packet sent to the next node is monitored for properreceipt

IP is a connection-less protocol, meaning that a packetsent to the next node is not monitored for properdelivery

Since TCP and IP work together, the packet delivery isreliable

Connection-less mode is known as User DatagramProtocol (UDP)

Application LayerTh A li i l id li i h bili h i f h h l


60/65

The Application layerprovides applications the ability to access the services of the other layersand defines the protocols that applications use to exchange data. There are many Application

layer protocols and new protocols are always being developed.

The most widely-known Application layer protocols are those used for the exchange of user

information:

The Hypertext Transfer Protocol(HTTP) is used to transfer files that make up the Webpages of the World Wide Web.

The File Transfer Protocol (FTP) is used for interactive file transfer.The Simple Mail Transfer Protocol (SMTP) is used for the transfer of mail messagesand attachments.

Telnet, a terminal emulation protocol, is used for logging on remotely to network hosts.

Additionally, the following Application layer protocols help facilitate the use and management ofTCP/IP networks:

The Domain Name System (DNS) is used to resolve a host name to an IP address.

The Routing Information Protocol (RIP) is a routing protocol that routers use to exchange

routing information.

The Simple Network Management Protocol (SNMP) is used between a network

management console and network devices (routers, bridges, intelligent hubs) to collect

and exchange network management information.Examples of Application layer interfaces for TCP/IP applications are Sockets and

NetBIOS. Sockets provides a standard application programming interface (API) for

interprocess communication via TCP/IP. NetBIOS is an industry standard interface for

accessing protocol services such as sessions, datagrams, and name resolution.
http://www.softpanorama.org/WWW/http_protocol.shtmlhttp://www.softpanorama.org/Mail/smtp_protocol.shtmlhttp://www.softpanorama.org/Mail/smtp_protocol.shtmlhttp://www.softpanorama.org/WWW/http_protocol.shtml


61/65

Transport Layer

The Transport layer(also known as the Host-to-Host Transport layer) isresponsible for providing the Application layer with session and datagram

communication services. The core protocols of the Transport layer are

Transmission Control Protocol(TCP) and the User Datagram Protocol(UDP). Either of these two protocols are used by the application layer

process, the choice depends on the application's transmission reliability

requirements.The mechanisms used by the Transport layer to determine whether data has

been correctly delivered are:

Acknowledgement responses

Sequencing

Flow control

The Transport layer facilitates end-to-end data transfer. It supports multipleoperations simultaneously. The layer is implemented by two protocols: the

Transmission Control Protocol (TCP) and the User Datagram Protocol

(UDP). TCP uses packets called segments, while UDP uses packets called

datagrams. Both TCP and UDP are encapsulated

inside Internet layer datagrams for transmission to the next node.

The Transport layer facilitates two types of communication:
http://www.softpanorama.org/Net/Transport_layer/index.shtmlhttp://www.softpanorama.org/Net/Transport_layer/index.shtmlhttp://www.softpanorama.org/Net/Transport_layer/index.shtmlhttp://www.softpanorama.org/Net/Transport_layer/index.shtml


62/65

The Transport layer facilitates two types of communication:

Connection-oriented (TCP) A connection must be established at theTransport layer of both systems before the application can transmit any data.

Connectionless (UDP) All systems do not need to establish a connectionwith the recipient prior to data exchange. TCP is a more reliable form of data

exchange than UDP.

TCP and UDP:TCP is a reliable, connection-oriented protocol that provides error checkingand flow control through a virtual link that it establishes and finally terminates.

TCP is responsible for the establishment of a TCP connection (TCP

handshake), the sequencing and acknowledgment of packets sent, and therecovery of packets lost during transmission.

UDP is an unreliable, connectionless protocol that provides data transportwith lower network traffic overheads than TCP. UDP is used when the amount of

data to be transferred is small (such as the data that would fit into a single

packet), or when the overhead of establishing a TCP connection is not desired

or when the applications or upper layer protocols provide reliable delivery. UDPdoes not error check or offer any flow control, this is left to the application

process. Still it can be used by protocols that provide reliable packet

transmission like NFS.

The Transport layer encompasses the responsibilities of the OSI Transport layer and

some of the responsibilities of the OSI Session layer.
http://www.softpanorama.org/Net/Transport_layer/tcp.shtmlhttp://www.softpanorama.org/Net/Transport_layer/tcp_handshake.shtmlhttp://www.softpanorama.org/Net/Transport_layer/tcp_handshake.shtmlhttp://www.softpanorama.org/Net/Transport_layer/udp.shtmlhttp://www.softpanorama.org/Net/Transport_layer/udp.shtmlhttp://www.softpanorama.org/Net/Transport_layer/tcp_handshake.shtmlhttp://www.softpanorama.org/Net/Transport_layer/tcp_handshake.shtmlhttp://www.softpanorama.org/Net/Transport_layer/tcp.shtml


63/65

This layer is responsible for addressing, packaging, and routing functions. It allowscommunication across networks of the same and different types and carries outtranslations to deal with dissimilar data addressing schemes. The core protocols of theInternet layer are IP, ARP, ICMP, and IGMP.

The Internet Protocol(IP) is a routable protocol responsible for IPaddressing, routing, and the fragmentation and reassembly of packets.

The Address Resolution Protocol(ARP) is responsible for the resolution ofthe Internet layer address to the Network Interface layer address such as a

hardware address.

The Internet Control Message Protocol(ICMP) is responsible for providingdiagnostic functions and reporting errors due to the unsuccessful delivery of

IP packets.

The Internet Group Management Protocol(IGMP) is responsible for themanagement of IP multicast groups.

The Internet layer is analogous to the Network layer of the OSI model.

Internet Layer
http://www.softpanorama.org/Net/Internet_layer/index.shtmlhttp://www.softpanorama.org/Net/Internet_layer/arp.shtmlhttp://www.softpanorama.org/Net/Internet_layer/arp.shtmlhttp://www.softpanorama.org/Net/Internet_layer/icmp.shtmlhttp://www.softpanorama.org/Net/Internet_layer/icmp.shtmlhttp://www.softpanorama.org/Net/Internet_layer/icmp.shtmlhttp://www.softpanorama.org/Net/Internet_layer/icmp.shtmlhttp://www.softpanorama.org/Net/Internet_layer/arp.shtmlhttp://www.softpanorama.org/Net/Internet_layer/arp.shtmlhttp://www.softpanorama.org/Net/Internet_layer/index.shtml


64/65

The Network Interface layer(also called the Network Access layer) is responsible forplacing TCP/IP packets on the network medium and receiving TCP/IP packets off the

network medium. TCP/IP was designed to be independent of the network access method,

frame format, and medium. In this way, TCP/IP can be used to connect differing network

types. This layer include LAN technologies such as Ethernet and Token Ring and WAN

technologies such as X.25 and Frame Relay. Independence from any specific network

technology gives TCP/IP the ability to be adapted to new technologies such asAsynchronous Transfer Mode (ATM). It consists of combination of datalink and physical

layers deals with pure hardware (wires, satellite links, network interface cards, etc.) and

access methods such as CSMA/CD (carrier sensed multiple access with collisiondetection).

Ethernet is the most popular network access layer protocol. Its hardware operates at the

physical layer and its medium access control method (CSMA/CD) operates at the datalink

layer. .The Network Interface layer encompasses the Data Link and Physical layers of the OSI

model. Note that the Internet layer does not take advantage of sequencing and

acknowledgment services that might be present in the Data-Link layer. An unreliable

Network Interface layer is assumed, and reliable communications through session

establishment and the sequencing and acknowledgment of packets is the responsibility of

the Transport layer.

Network Interface Layer
http://burks.bton.ac.uk/burks/pcinfo/hardware/ethernet/nic.htmhttp://www.softpanorama.org/Net/Network_interface_layer/ethernet.shtmlhttp://burks.bton.ac.uk/burks/pcinfo/hardware/ethernet/mac.htmhttp://burks.bton.ac.uk/burks/pcinfo/hardware/ethernet/mac.htmhttp://www.softpanorama.org/Net/Network_interface_layer/ethernet.shtmlhttp://burks.bton.ac.uk/burks/pcinfo/hardware/ethernet/nic.htm


65/65

THANK YOU

descriptive discussion on tcp/ip..!

Documents