Data communication part1

DATCOMMIntroduction to Data

and Computer Networks

Engr. Melvin K. Cabatuan, MsE

De La Salle University

January 2013

Objectives

- Identify the scope and significance of DataComputer Networking in today’s world

- Define and illustrate Data Communicationsand Data Network.

- Describe the Network Components and itsArchitecture.

- Illustrate and explain the Internet.- Explain the various Network CommunicationModels

Objectives

- Illustrate and explain the Internet.

- Explain the various Network CommunicationModels

Objectives

Why Study Networks?- Networks support and improve our lives byproviding instantaneous local or globalcommunications.

Why Study Networks?- Networks improve teaching and learningthrough sharing and collaboration.

Why Study Networks?

- Networks change the way we work.

Why Study Networks?- Networks supports the way we play.

Data Communications

- are the transfer of data from one device toanother via some form of transmission medium.

Data Communications- are the transfer of data from one device toanother via some form of transmission medium.

Data Communications

- The five components that make up a datacommunications system are the message,sender, receiver, medium, and protocol.

Possible Quiz QuestionA set of rules that govern data communications. Itrepresents an agreement between thecommunicating devices. Without it, two devicesmay be connected but not communicating.

A. MessageB. SenderC. ReceiverD. MediumE. Protocol

Possible Quiz QuestionA set of rules that govern data communications. Itrepresents an agreement between thecommunicating devices. Without it, two devicesmay be connected but not communicating.

A. MessageB. SenderC. ReceiverD. MediumE. Protocol X

Possible Quiz Question

It is a fundamental characteristics of a datacommunication system which refers to thevariation in the packet arrival time.

A. JitterB. AccuracyC. TimelinessD. DeliveryE. All of the above

It is a fundamental characteristics of a datacommunication system which refers to thevariation in the packet arrival time.

A. Jitter X

B. AccuracyC. TimelinessD. DeliveryE. All of the above

�Remember- Delivery.The system must deliver data to the correctdestination.

- Accuracy.The system must deliver the data accurately.

- Timeliness.The system must deliver data in a timelymanner.

- Jitter.Jitter refers to the variation in the packetarrival time.

What is a Network?Notes

What is a Network?- A set of communication devices (nodes)connected by media links capable of carryingdifferent types of communications.

�Remember

- DevicesThese are used to communicate with oneanother.

- MediumThis is how the devices are connected together.

- MessagesInformation that travels over the medium.

- Rules / ProtocolGoverns how messages flow across network.

�Remember

Computer NetworkNotes

Computer Network- A network of "computers".

Why Network Computers?

- To increase productivity by linking computersand computer networks allowing users to shareresources and data. Ex.

- Data and applications- Resources, i.e. I/O devices like cameras &printers

- Network Storage- Backup devices

- Data and applications

- Resources, i.e. I/O devices like cameras &printers

- Network Storage

- Backup devices

Why Network Computers?- Reduced Cost and Easier Installation ofSoftware.

- Ex. Network installation

- Improved Security

- Improved Communications- More Workplace Flexibility- Reduced Cost of Peripherals- Centralized Administration

- Improved Security- Improved Communications

- More Workplace Flexibility- Reduced Cost of Peripherals- Centralized Administration

- Improved Security- Improved Communications- More Workplace Flexibility

- Reduced Cost of Peripherals- Centralized Administration

- Improved Security- Improved Communications- More Workplace Flexibility- Reduced Cost of Peripherals

- Centralized Administration

- Improved Security- Improved Communications- More Workplace Flexibility- Reduced Cost of Peripherals- Centralized Administration

Network Requirements?

- At least two computers

- A resource that needs to be shared- A transmission medium- A communications agreement

- At least two computers- A resource that needs to be shared

- A transmission medium- A communications agreement

- At least two computers- A resource that needs to be shared- A transmission medium

- A communications agreement

- At least two computers- A resource that needs to be shared- A transmission medium- A communications agreement

Network CategoryBy type of MEDIA

- Wired and Wireless

Network Media- this is the channel over which a message travels

Network CategoryBy COVERAGE

Local Area NetworkLAN

- Can be as small as two computers.- Laboratory w/ networked computers.- A network within a building or severalbuildings.

- Speed at 10, 100, or 1000 Mbps

- Can be as small as two computers.

- Laboratory w/ networked computers.- A network within a building or severalbuildings.

- Can be as small as two computers.- Laboratory w/ networked computers.

- A network within a building or severalbuildings.

Metropolitan Area NetworkMAN

- covers the area inside a town or a city.- Ex. Cable TV network

- covers the area inside a town or a city.

- Ex. Cable TV network

- covers the area inside a town or a city.- Ex. Cable TV network

Wide Area NetworkWAN

- provides long-distance transmission of data,image, audio, and video information over largegeographic areas that may comprise a country,a continent, or even the whole world.

Wide Area NetworkWAN

- provides long-distance transmission of data,image, audio, and video information over largegeographic areas that may comprise a country,a continent, or even the whole world.

Interconnection of Networks:Internetwork

- Today, it is very rare to see a LAN, a MAN inisolation; they are connected to one another.

- When two or more networks are connected,they become an internetwork, or internet.

Example

- Assume that an organization has two offices,one in Manila and the other in Cebu. Theestablished office on Manila has a bus topologyLAN; the newly opened office on Cebu has astar topology LAN. The president of thecompany lives somewhere in the middle andneeds to have control over the company fromher home in Boracay.

Example- To create a backbone WAN for connectingthese three entities (two LANs and thepresident’s computer), a switched WAN(operated by a service provider such as atelecom company) has been leased. To connectthe LANs to this switched WAN, however,three point-to-point WANs are required. Thesepoint-to-point WANs can be a high-speed DSLline offered by a telephone company or a cablemodern line offered by a cable TV provider.

IllustrationFour WANs + two LANs

Virtual Private NetworkVPN

- It enables a host computer to send and receivedata across shared or public networks as if itwere a private network with all thefunctionality

Virtual Private NetworkVPN

- It enables a host computer to send and receivedata across shared or public networks as if itwere a private network with all thefunctionality

Other Networks- Campus Area Network, Corporate AreaNetwork (CAN)essentially a local area network.

- Personal Area Network (PAN)A network, typically of devices centered aroundthe user

- Wireless PAN (WPAN)a typical implementation of a PAN

- Sensor NetworksA specialized network of devices typically usedfor monitoring

Network Topology

Network TopologyFour Basic Topologies

Mesh Topology- Every device has a dedicated point-to-pointlink to every other device.

- How many duplex-mode links do we have on amesh network with n nodes?

Mesh TopologyAdvantages

- Dedicated links guarantees that eachconnection can carry its own data load, thuseliminating the traffic problems.

- A mesh topology is robust.- The advantage of privacy or security.- Point-to-point links make fault identificationand fault isolation easy.

- A mesh topology is robust.

- The advantage of privacy or security.- Point-to-point links make fault identificationand fault isolation easy.

- A mesh topology is robust.- The advantage of privacy or security.

- Point-to-point links make fault identificationand fault isolation easy.

- A mesh topology is robust.- The advantage of privacy or security.- Point-to-point links make fault identificationand fault isolation easy.

Mesh TopologyDisadvantages

- Installation and reconnection are difficultbecause every device must be connected toevery other device.

- Bulk of the wiring can be greater than theavailable space (in walls, ceilings, or floors) canaccommodate.

- Hardware required to connect each link (I/Oports and cable) can be prohibitively expensive.

Star Topology

- Each device has a dedicated point-to-point linkonly to a central controller, usually called ahub.

Star TopologyAdvantages

- Less expensive than a mesh topology.

- Easy to install and reconfigure.- Easy fault identification and fault isolation.- Relatively robust because if one link fails, onlythat link is affected.

- Less expensive than a mesh topology.- Easy to install and reconfigure.

- Easy fault identification and fault isolation.- Relatively robust because if one link fails, onlythat link is affected.

- Less expensive than a mesh topology.- Easy to install and reconfigure.- Easy fault identification and fault isolation.

- Relatively robust because if one link fails, onlythat link is affected.

- Less expensive than a mesh topology.- Easy to install and reconfigure.- Easy fault identification and fault isolation.- Relatively robust because if one link fails, onlythat link is affected.

Star TopologyDisadvantages

- Dependency of the whole topology on onesingle point, the hub. If the hub goes down, thewhole system is dead.

- Often more cabling is required in a star than insome other topologies (such as ring or bus).

Star TopologyDisadvantages

- Dependency of the whole topology on onesingle point, the hub. If the hub goes down, thewhole system is dead.

- Often more cabling is required in a star than insome other topologies (such as ring or bus).

Bus Topology

- One long cable acts as a backbone to link allthe devices in a network.

- Drop line is a connection running between thedevice and the main cable.

Bus TopologyAdvantages

- Ease of installation.

- Uses less cabling than mesh or star topologies,hence less expensive.

Bus TopologyAdvantages

- Ease of installation.- Uses less cabling than mesh or star topologies,hence less expensive.

Bus TopologyDisadvantages

- Difficult reconnection and fault isolation.

- Difficult to add new devices.- Signal reflection at the taps can causedegradation in quality.

- A fault or break in the bus cable stops alltransmission.

- Difficult reconnection and fault isolation.- Difficult to add new devices.

- Signal reflection at the taps can causedegradation in quality.

- Difficult reconnection and fault isolation.- Difficult to add new devices.- Signal reflection at the taps can causedegradation in quality.

Ring Topology- Each device has a dedicated point-to-pointconnection with only the two devices on eitherside of it.

- When a device receives a signal intended foranother device, its repeater regenerates the bitsand passes them along.

Ring TopologyAdvantages

- Easy to install and reconfigure.

- Fault isolation is simplified. Generally in a ring,a signal is circulating at all times. If one devicedoes not receive a signal within a specifiedperiod, it can issue an alarm.

Ring TopologyAdvantages

- Easy to install and reconfigure.- Fault isolation is simplified. Generally in a ring,a signal is circulating at all times. If one devicedoes not receive a signal within a specifiedperiod, it can issue an alarm.

Ring TopologyDisadvantages

- Unidirectional traffic can be a disadvantage. Ina simple ring, a break in the ring (such as adisabled station) can disable the entirenetwork.

- Today, the need for higher-speed LANs hasmade this topology less popular.

Ring TopologyDisadvantages

- Unidirectional traffic can be a disadvantage. Ina simple ring, a break in the ring (such as adisabled station) can disable the entirenetwork.

- Today, the need for higher-speed LANs hasmade this topology less popular.

Network ArchitectureAccording to Security Relationships

- Peer-to-peer Network (P2P).

- Client-server Network.

Network ArchitectureAccording to Security Relationships

- Peer-to-peer Network (P2P).- Client-server Network.

Peer-to-peer Network (P2P)Workgroup

- shared data is distributed on each computers.

Peer-to-peer Network (P2P)Workgroup

Peer-to-peer Network (P2P)Pros and Cons

- Advantages◦ Low cost◦ Easy to set up◦ No server required

- Disadvantages◦ No centralized control of security◦ Administrative burden of maintainingaccounts on all computers ◦ Not scalable

Peer-to-peer Network (P2P)Pros and Cons

- Advantages◦ Low cost◦ Easy to set up◦ No server required

- Disadvantages◦ No centralized control of security◦ Administrative burden of maintainingaccounts on all computers ◦ Not scalable

Client-server Network

- shared data is centralized on a device called afile server.

Client-server NetworkNotes

Client-server NetworkPros and Cons

- Advantages◦ Centralized administration◦ Single sign-on◦ Reduced broadcast traffic◦ Scalability

- Disadvantages◦ Higher cost◦ More challenging technically◦ Single point of failure with a single file server

Client-server NetworkPros and Cons

- Advantages◦ Centralized administration◦ Single sign-on◦ Reduced broadcast traffic◦ Scalability

- Disadvantages◦ Higher cost◦ More challenging technically◦ Single point of failure with a single file server

Network Transmission Modes

- Unicast (One-to-one).a single source host is sending information to asingle destination host

- Broadcast (One-to-many).a single host is sending information to all otherhosts on the network

- Multicast (One-to-some).a single host is sending a transmission to some,but not all hosts

Transmission ModesIllustration

Network Representations

Heirarchical TopologyCisco hierarchical model

- Core layer ==> backbone- Distribution layer ==> routing- Access layer ==> switching

- Core layer ==> backbone

- Distribution layer ==> routing- Access layer ==> switching

- Core layer ==> backbone- Distribution layer ==> routing

- Access layer ==> switching

- Core layer ==> backbone- Distribution layer ==> routing- Access layer ==> switching

Cisco hierarchical modelCore layer (Backbone)

- Literally the core of the network.- Switch large amounts of traffic both reliablyand quickly.

- If there is a failure in the core, every single usercan be affected.

- Literally the core of the network.

- Switch large amounts of traffic both reliablyand quickly.

Cisco hierarchical modelDistribution layer (Routing)

- sometimes referred to as the workgroup layer.- provides routing, filtering, and WAN accessand to determine how packets can access thecore, if needed.

- Place to implement security and policies for thenetwork including address translation andfirewalls.

- sometimes referred to as the workgroup layer.

- provides routing, filtering, and WAN accessand to determine how packets can access thecore, if needed.

Cisco hierarchical modelAccess layer (Switching)

- sometimes referred to as the desktop layer.- controls user and workgroup access tointernetwork resources.

- segmentation

- sometimes referred to as the desktop layer.

- controls user and workgroup access tointernetwork resources.

- segmentation

Structure of the Internet

- Hierarchical- Common standards- Common protocols

Structure of the Internet- Hierarchical

- Common standards- Common protocols

Structure of the Internet- Hierarchical- Common standards

- Common protocols

Structure of the Internet- Hierarchical- Common standards- Common protocols

Access NetworksConnects end hosts to the network core

RESIDENTIAL ACCESS:

- Dial-up modem via Public Switched TelephoneNetwork

- DSL- Cable Broadband- Wireless Broadband (Wimax, etc.)- FTTH

ACCESS WITHIN ENTERPRISE LAN’s:

- Ethernet/IEEE 802.3 and Wifi

RESIDENTIAL ACCESS:

- Cable Broadband- Wireless Broadband (Wimax, etc.)- FTTH

RESIDENTIAL ACCESS:

- DSL- Cable Broadband

- Wireless Broadband (Wimax, etc.)- FTTH

RESIDENTIAL ACCESS:

- DSL- Cable Broadband- Wireless Broadband (Wimax, etc.)

- FTTHACCESS WITHIN ENTERPRISE LAN’s:

RESIDENTIAL ACCESS:

WAN Technologies

- Links the components of the Internetwork core.- Includes:X.25Frame RelayISDN, BISDNATMSONET/SDH

WAN Technologies

- Links the components of the Internetwork core.

- Includes:X.25Frame RelayISDN, BISDNATMSONET/SDH

WAN Technologies

- Links the components of the Internetwork core.- Includes:X.25Frame RelayISDN, BISDNATMSONET/SDH

Packet SwitchingThe Internet and other computer networks usepacket switching

- A persistent path for signals/data (circuit) isnot necessary for duration of communications.

- Data is broken down into chunks (packets) andeach piece is sent through the network.

- Each packet may take various paths throughthe network.

- Packets may arrive out of sequence.

Packet Switching

�Remember- X.25 (64-kbps)A virtual-circuit switching network withextensive flow and error control.

- Frame Relay (1.544 - 44.376 Mbps)uses variable-length packets, called frames;strips out most of the overhead involved witherror control.

- Asynchronous transfer mode (ATM)uses fixed-length packets, called cells.(10s, 100s of Mbps, and Gbps range)

Quality of ServiceQoS

- treat different traffic flows differently.

- ensure quality of service for applications that require it.

- appropriate QoS strategy for a given type of traffic.

ProtocolsRules

- shared conventions for communicatinginformation.

- defines WHAT is communicated, HOW it iscommunicated, and WHEN it is communicated.

- Protocols specifySyntax: Data format, and Signal levelsSemantics: Meaning of each bit section; Flowcontrol, Error handlingTiming: Speed match, and Sequencing

ProtocolsRules

ProtocolsIllustration

Protocol Architecture

- specifies how a protocol is organized andimplemented.

- layered structure of hardware and software thatsupports the exchange of data between systemsand supports distributed applications, such asemail and file transfer.

- at each layer of a protocol architecture, one ormore common protocols are implemented incommunicating systems.

Protocol Architecture- Two approaches1. Monolithic (single module)2. Modular (layered)

- Advantages of Modular Approach1. Breaks complex tasks into subtasks.2. Changes in one layer do not affect otherlayers.

Protocol Architecture- Two approaches1. Monolithic (single module)2. Modular (layered)

- Advantages of Modular Approach1. Breaks complex tasks into subtasks.2. Changes in one layer do not affect otherlayers.

Layered ModelIllustration

Layered Protocol Architecture

- Each layers acts as a module.

- Communication occurs1. between different modules on the samesystem2. between similar modules on different systems

Layered Protocol Architecture

- Each layers acts as a module.- Communication occurs1. between different modules on the samesystem2. between similar modules on different systems

Layered ArchitectureExample

- Open Systems Interconnection model (OSI).

OSI Reference Model

- layered framework developed by InternationalOrganization for Standardization (ISO) for thedesign of network systems that allowscommunication between all types of computersystems.

- consists of seven separate but related layers,each of which defines a part of the process ofmoving information across a network.

- not a protocol; it is a reference model.

OSI Reference Model

OSI Reference ModelHost-to-host link

OSI Model Layers

- Layers 1, 2, and 3 - physical, data link, andnetwork - are the network support layers

- they deal with the physical aspects of movingdata from one device to another (such aselectrical specifications, physical connections,physical addressing, and transport timing andreliability)

OSI Model Layers

- Layers 1, 2, and 3 - physical, data link, andnetwork - are the network support layers

- they deal with the physical aspects of movingdata from one device to another (such aselectrical specifications, physical connections,physical addressing, and transport timing andreliability)

OSI Model Layers

- Layers 5, 6, and 7 - session, presentation, andapplication - can be thought of as the usersupport layers;they allow interoperability among unrelatedsoftware systems.

- Layer 4, the transport layer, links the twosubgroups and ensures that what the lowerlayers have transmitted is in a form that theupper layers can use.

OSI Model Layers

- Layers 5, 6, and 7 - session, presentation, andapplication - can be thought of as the usersupport layers;they allow interoperability among unrelatedsoftware systems.

- Layer 4, the transport layer, links the twosubgroups and ensures that what the lowerlayers have transmitted is in a form that theupper layers can use.

Physical Layer (PHY)

- is responsible for movements of individual bitsfrom one hop (node) to the next.

- coordinates the functions required to carry abit stream over a physical medium.

- deals with the mechanical and electricalspecifications of the interface and transmissionmedium.

- defines the procedures and functions thatphysical devices and interfaces have to performfor transmission to occur

Physical Layer Concerns

- Physical characteristics of interfaces andmedium.

- Representation of bits.- Data rate.- Synchronization of bits.- Physical topology.- Line configuration.- Transmission mode.

- Representation of bits.

- Data rate.- Synchronization of bits.- Physical topology.- Line configuration.- Transmission mode.

- Representation of bits.- Data rate.

- Synchronization of bits.- Physical topology.- Line configuration.- Transmission mode.

- Representation of bits.- Data rate.- Synchronization of bits.

- Physical topology.- Line configuration.- Transmission mode.

- Representation of bits.- Data rate.- Synchronization of bits.- Physical topology.

- Line configuration.- Transmission mode.

- Representation of bits.- Data rate.- Synchronization of bits.- Physical topology.- Line configuration.

- Transmission mode.

- Representation of bits.- Data rate.- Synchronization of bits.- Physical topology.- Line configuration.- Transmission mode.

�RememberLine Configurationconnection of devices to the media.

- Point-to-point configurationtwo devices are connected through a dedicatedlink.

- Multipoint configurationa link is shared among several devices

�RememberLine Configurationconnection of devices to the media.

- Point-to-point configurationtwo devices are connected through a dedicatedlink.

- Multipoint configurationa link is shared among several devices

�RememberTransmission modedirection of transmission between two devices.

- Simplex modeonly one device can send; the other can onlyreceive.

- Half-duplex modetwo devices can send and receive, but not atthe same time.

- Full-duplex modetwo devices can send and receive at the sametime.

Transmission modeData flow(simplex, half-duplex, and full-duplex)

Data Link Layer (DLL)or simply Link Layer

- is responsible for moving frames from one hop(node) to the next.

Data Link Layer (DLL)

- transforms the physical layer, a rawtransmission facility, to a reliable link.

- makes the physical layer appear error-free tothe upper layer (network layer).

Data Link Layer (DLL)

- transforms the physical layer, a rawtransmission facility, to a reliable link.

- makes the physical layer appear error-free tothe upper layer (network layer).

Data Link Layer Concerns- Framingdivides the stream of bits received from thenetwork layer into manageable data unitscalled frames

- Physical addressingadds a header to the frame to define the senderand/or receiver of the frame. If the frame isintended for a system outside the sender’snetwork, the receiver address is the address ofthe device that connects the network to thenext one.

Data Link Layer Concerns- Framingdivides the stream of bits received from thenetwork layer into manageable data unitscalled frames

- Physical addressingadds a header to the frame to define the senderand/or receiver of the frame. If the frame isintended for a system outside the sender’snetwork, the receiver address is the address ofthe device that connects the network to thenext one.

Data Link Layer (DLL)Hop-to-hop delivery

- communication at the data link layer occursbetween two adjacent nodes

Data Link Layer Concerns- Flow controlimposes a flow control mechanism to avoidoverwhelming the receiver.

- Error controlAdds reliability to the physical layer by addingmechanisms to detect and retransmit damagedor lost frames.

- Access controlin multipoint configuration, link layer protocolsare necessary to determine which device hascontrol over the link at any given time.

Data Link Layer Example

- Ethernet (802.3) and Media Access Control(MAC) address applied to the network adaptorby the manufacturer during production.

Network Layer

- is responsible for the delivery of individual packetsfrom the source host to the destination host.

Network Layer

- ensures that each packet gets from its point oforigin to its final destination.

- If two systems are connected to the same link,there is usually no need for a network layer.

- If the two systems are attached to differentnetworks with connecting devices between thenetworks, there is often a need for the networklayer to accomplish source-to-destinationdelivery.

Network Layer

Network Layer Concerns

- Logical addressingif a packet passes the network boundary, weneed another addressing system to helpdistinguish the source and destination systems.

- Routingprovides mechanism to route or set the path ofthe packets to their final destination

Network Layer Concerns

- Logical addressingif a packet passes the network boundary, weneed another addressing system to helpdistinguish the source and destination systems.

- Routingprovides mechanism to route or set the path ofthe packets to their final destination

Network LayerNotes

Transport Layer- is responsible for process-to-process delivery ofthe entire message.

- a process is an application program running ona host.

Transport Layer- is responsible for process-to-process delivery ofthe entire message.

- a process is an application program running ona host.

Transport Layer

- ensures that the whole message arrives intactand in order.

�Understand- The network layer gets each packet to thecorrect computer; the transport layer gets theentire message to the correct process on thatcomputer.

- Network layer does not recognize anyrelationship between the packets it delivers andtreats each one independently.

- The transport layer, however, ensures that thewhole message arrives intact and in order,overseeing both error control and flow control.

Transport Layer Concerns

- Service-point addressingaddress for delivery from a specific process(running program) on one computer to aspecific process (running program) on theother.

- Segmentation and reassemblymessage is divided into transmittable segments,with each segment containing a sequencenumbers enabling the transport layer toreassemble the message correctly.

- Service-point addressingaddress for delivery from a specific process(running program) on one computer to aspecific process (running program) on theother.

- Segmentation and reassemblymessage is divided into transmittable segments,with each segment containing a sequencenumbers enabling the transport layer toreassemble the message correctly.

- Connection controleither connectionless or connection-oriented.

- End-to-end Flow control- Process-to-process Error control- Transport layer protocol and the port number

- End-to-end Flow control

- Process-to-process Error control- Transport layer protocol and the port number

- End-to-end Flow control- Process-to-process Error control

- Transport layer protocol and the port number

- End-to-end Flow control- Process-to-process Error control- Transport layer protocol and the port number

Session Layer- is responsible for dialog control andsynchronization.

- establishes, maintains, & synchronizes theinteraction among communicating systems.

Session Layer- is responsible for dialog control andsynchronization.

- establishes, maintains, & synchronizes theinteraction among communicating systems.

Session Layer Concerns

- Dialog controlallows two systems to enter into a dialogallows the communication between twoprocesses to take place in either half-duplex orfull-duplex mode.

- Synchronizationallows a process to add checkpoints, orsynchronization points, to a stream of data.

Session Layer Concerns

- Dialog controlallows two systems to enter into a dialogallows the communication between twoprocesses to take place in either half-duplex orfull-duplex mode.

- Synchronizationallows a process to add checkpoints, orsynchronization points, to a stream of data.

Presentation Layer

- is responsible for translation, compression, andencryption.

- concerned with the syntax and semantics of theinformation exchanged between two systems.

Presentation Layer

- is responsible for translation, compression, andencryption.

- concerned with the syntax and semantics of theinformation exchanged between two systems.

Presentation Layer Concerns

- Translationresponsible for interoperability betweendifferent encoding methods

- Encryptionthe sender transforms the original informationto another form and sends the resultingmessage.

- Compressionreduce the number of bits.

Presentation Layer Examples

- JPEG- Joint Photographic Experts Group

- MPEG- The Moving Picture Experts Group’sstandard

- MIDI- Musical Instrument Digital Interface- TIFF- Tagged Image File Format

- JPEG- Joint Photographic Experts Group- MPEG- The Moving Picture Experts Group’sstandard

- MIDI- Musical Instrument Digital Interface

- TIFF- Tagged Image File Format

Application Layer- is responsible for providing services to the user.

- enables the user, whether human or software,to access the network.

Application Layer- is responsible for providing services to the user.- enables the user, whether human or software,to access the network.

Application LayerThe Interface Between Human and Data Networks

Application Layer Concerns

- Network virtual terminala software version of a physical terminal, and itallows a user to log on to a remote host.

- File transfer, access, and managementallows a user to access files in a remote host,and to manage or control files

- Mail services- Directory services

- Mail services

- Directory services

Application LayerNotes

Application Layer Examples

- World Wide Web (WWW)

- E-mail gateways- Internet navigation utilities- Financial transaction services- Domain Name System (DNS) queries- File Transfer Protocol (FTP) transfers- Simple Mail Transfer Protocol (SMTP) emailtransfers

- World Wide Web (WWW)- E-mail gateways

- Internet navigation utilities- Financial transaction services- Domain Name System (DNS) queries- File Transfer Protocol (FTP) transfers- Simple Mail Transfer Protocol (SMTP) emailtransfers

- World Wide Web (WWW)- E-mail gateways- Internet navigation utilities

- Financial transaction services- Domain Name System (DNS) queries- File Transfer Protocol (FTP) transfers- Simple Mail Transfer Protocol (SMTP) emailtransfers

- World Wide Web (WWW)- E-mail gateways- Internet navigation utilities- Financial transaction services

- Domain Name System (DNS) queries- File Transfer Protocol (FTP) transfers- Simple Mail Transfer Protocol (SMTP) emailtransfers

- World Wide Web (WWW)- E-mail gateways- Internet navigation utilities- Financial transaction services- Domain Name System (DNS) queries

- File Transfer Protocol (FTP) transfers- Simple Mail Transfer Protocol (SMTP) emailtransfers

- World Wide Web (WWW)- E-mail gateways- Internet navigation utilities- Financial transaction services- Domain Name System (DNS) queries- File Transfer Protocol (FTP) transfers

- Simple Mail Transfer Protocol (SMTP) emailtransfers

- World Wide Web (WWW)- E-mail gateways- Internet navigation utilities- Financial transaction services- Domain Name System (DNS) queries- File Transfer Protocol (FTP) transfers- Simple Mail Transfer Protocol (SMTP) emailtransfers

OSI Reference ModelData exchange and Encapsulation

Data Encapsulation

- To communicate and exchange information,each layer uses Protocol Data Units (PDUs).These hold the control information attached tothe data at each layer of the model.

- The data portion at levelN – 1 carries the whole PDU (data and headerand maybe trailer) from level N.

- For level N – 1, the whole PDU coming fromlevel N is treated as one integral unit.

Data Encapsulation

Data EncapsulationNotes

Data EncapsulationPDU and layer Addressing

Data Segmentation- Segment the data stream into small boundedsize blocks or PDUs.

- the network may accept data blocks only up toa certain size (53 octets for atm, 1526 octetsfor Ethernet)

- Advantages◦ Efficient error control with PDU size ◦ Fewerbits retransmitted in the event of failure ◦Better access to shared transmission facilities,with shorter delay ◦ Smaller buffers at receiverstations

Data Segmentation

- Disadvantages◦ Larger overhead with smaller PDU size◦ More interrupts as PDUs announce theirarrival◦ More time spent to process many smallerPDUs◦ Reassembly is an issue to be addressed

OSI Example

Imagine that you are on DLSU website and youhave clicked a link on the page. By doing so youhave just made a request of the web server to sendyou a document (most web pages exist asdocuments with an .html extension). Thisdocument will be sent to your computer which willuse the proper application (your Internet browser)to display the document so you can view it.

Example

Web server EndSOURCE

- Layer 7 obtains the data in the form of theHTML document.

- Layer 6 adds information about the formatting.- Layer 5 adds information required to create asession between the web server and the webbrowser on the laptop.

- Layer 6 adds information about the formatting.

- Layer 5 adds information required to create asession between the web server and the webbrowser on the laptop.

- Layer 6 adds information about the formatting.- Layer 5 adds information required to create asession between the web server and the webbrowser on the laptop.

- Layer 4 adds the transport protocol and thesource and destination port numbers, in thiscase TCP (it’s a unicast) and port 80 (HTTP).

- Layer 3 adds the source and destination IPaddresses, in this case a source of 192.168.5.1and a destination of 192.168.5.2.

- Layer 4 adds the transport protocol and thesource and destination port numbers, in thiscase TCP (it’s a unicast) and port 80 (HTTP).

- Layer 3 adds the source and destination IPaddresses, in this case a source of 192.168.5.1and a destination of 192.168.5.2.

Web server endSOURCE

- Layer 2 learns the destination MAC addressand adds the source and destination MACaddresses, in this case, a source of 5-5-5-5-5-5and destination of 6-6-6-6-6-6.

- Layer 1 converts the entire package into bitsand sends it across the network to the laptop.

Web server endSOURCE

- Layer 2 learns the destination MAC addressand adds the source and destination MACaddresses, in this case, a source of 5-5-5-5-5-5and destination of 6-6-6-6-6-6.

- Layer 1 converts the entire package into bitsand sends it across the network to the laptop.

Laptop endDESTINATION

- Layer 1 receives the bits in electrical format,converts them to be read by layer 2, and handsthem to layer 2.

- Layer 2 examines the destination MAC addressto see whether it is addressed to it, sees theMAC address of 6-6-6-6-6 (its own), drops thatpart of the transmission, and hands theremaining data to layer 3.

- Layer 3 examines the destination IP address toensure that it is its own (192. 168.5.2), dropsthat part, and hands the rest of the package tolayer 4.

- Layer 4 examines the destination port number(port 80), alerts the browser that HTTP datais coming in, drops that part, and hands therest of the package to layer 5.

- Layer 5 uses the information that was placedon this layer by the web server to create thesession between the web server and the webbrowser and then hands the rest of theinformation to layer 6.

- Layer 4 examines the destination port number(port 80), alerts the browser that HTTP datais coming in, drops that part, and hands therest of the package to layer 5.

- Layer 5 uses the information that was placedon this layer by the web server to create thesession between the web server and the webbrowser and then hands the rest of theinformation to layer 6.

- Layer 6 performs any format translation thatmay be required and hands the remaining data(the HTML document) to layer 7.

- The layer 7 application (the web browser)receives the HTML document and opens thedocument in the browser window.

- Layer 6 performs any format translation thatmay be required and hands the remaining data(the HTML document) to layer 7.

- The layer 7 application (the web browser)receives the HTML document and opens thedocument in the browser window.

�UnderstandWhich of the following is not an advantage ofnetworking reference models?A. They encourage standardization by defining what functionsare performed at particular layers of the model.B. They prevent changes in one layer from causing a need forchanges in other layers, speeding development.C. They ensure that networks perform better.D. They encourage vendors to build on each other’sdevelopments through use of a common framework.E. None of the above

�UnderstandWhich of the following is not an advantage ofnetworking reference models?A. They encourage standardization by defining what functionsare performed at particular layers of the model.B. They prevent changes in one layer from causing a need forchanges in other layers, speeding development.C. They ensure that networks perform better. X

D. They encourage vendors to build on each other’sdevelopments through use of a common framework.E. None of the above

�UnderstandWhich layer of the OSI model is responsible forcoordinating the exchanges of information betweenthe layer 7 applications or services that are in use?

A. ApplicationB. SessionC. Data-LinkD. PhysicalE. None of the above

�UnderstandWhich layer of the OSI model is responsible forcoordinating the exchanges of information betweenthe layer 7 applications or services that are in use?

A. ApplicationB. Session X

C. Data-LinkD. PhysicalE. None of the above

�Understand

What is the information that is used on layer 3 ofthe OSI model?

A. A bit patternB. MAC addressesC. IP addressesD. Port numbersE. All of the above

�Understand

What is the information that is used on layer 3 ofthe OSI model?

A. A bit patternB. MAC addressesC. IP addresses X

D. Port numbersE. All of the above

�Reading Assignment

- Illustrate and Contrast OSI andTCP/IP models.

OSI and TCP/IP modelsComparison

OSI and TCP/IP Model

- There are seven layers in the OSI model andfour in the TCP/IP model.

- The top three layers of the OSI model(Application, Presentation and Session) map tothe Application layer of the TCP/IP model.

- The bottom two layers of the OSI model(Data-Link and Physical) map to the NetworkAccess layer of the TCP/IP model.

OSI vs. TCP/IP Model

- In the OSI model, it was envisioned that theSession layer would handle the establishmentand management of the communication sessionbetween the application or service being used.

- In TCP/IP, those functions are performed bythe TCP /IP protocol itself at a different layer,the Transport layer.

- In the OSI model, it was envisioned that theSession layer would handle the establishmentand management of the communication sessionbetween the application or service being used.

- In TCP/IP, those functions are performed bythe TCP /IP protocol itself at a different layer,the Transport layer.

- OSI model envisioned the host devices as deaf,dumb, and blind bystanders to the networkingprocess, not participants (dumb terminal).

- In TCP/IP, the hosts participate and take partin functions such as end-to-end verification,routing, and network control (intelligent roleplayers)

- OSI model envisioned the host devices as deaf,dumb, and blind bystanders to the networkingprocess, not participants (dumb terminal).

- In TCP/IP, the hosts participate and take partin functions such as end-to-end verification,routing, and network control (intelligent roleplayers)

- When TCP/IP was developed, it was decidedthat the division of the bottom layer intoData-Link and Physical layers was unnecessary.

- Thus their functions are combined in theNetwork Access layer of the TCP/IP model.

- When TCP/IP was developed, it was decidedthat the division of the bottom layer intoData-Link and Physical layers was unnecessary.

- Thus their functions are combined in theNetwork Access layer of the TCP/IP model.

TCP/IP Model

- Developed by US Defense Advanced ResearchProject Agency (DARPA) for ARPANETpacket switched network.

- generally referred to as the TCP/IP protocolsuite, which consists of a large collection ofprotocols.

- predates the OSI reference model.

TCP/IP Model

TCP/IP Model- Transmission Control Protocol (TCP)is the primary transport layer (layer 4)protocol, and is responsible for connectionestablishment and management and reliabledata transport between software processes ondevices.

- Internet Protocol (IP)is the primary OSI network layer (layer 3)protocol that provides addressing, datagramrouting and other functions in an internetwork.

TCP/IP Model- Transmission Control Protocol (TCP)is the primary transport layer (layer 4)protocol, and is responsible for connectionestablishment and management and reliabledata transport between software processes ondevices.

- Internet Protocol (IP)is the primary OSI network layer (layer 3)protocol that provides addressing, datagramrouting and other functions in an internetwork.

TCP/IP ModelNotes

TCP/IP Layers

- Application (Process) Layer

- Host-to-host (Transport) Layer- Internet Layer- Network Access/Interface Layer

TCP/IP Layers

- Application (Process) Layer- Host-to-host (Transport) Layer

- Internet Layer- Network Access/Interface Layer

TCP/IP Layers

- Application (Process) Layer- Host-to-host (Transport) Layer- Internet Layer

- Network Access/Interface Layer

TCP/IP Layers

- Application (Process) Layer- Host-to-host (Transport) Layer- Internet Layer- Network Access/Interface Layer

TCP/IP Model CommunicationProcess

Application (Process) layer

- corresponds to the OSI’s Application,Presentation, and Session layers

- defines protocols for node-to-node applicationcommunication

- controls user-interface specifications.

Application layer services

Application layer servicesNotes

�Recall

Telnet / Terminal Emulation- allows a user on a remote client machine, calledthe Telnet client, to access the resources ofanother machine, the Telnet server.

Telnet / Terminal Emulation

Domain Name ServiceDNS

- resolves hostnames-specifically, Internet names,such as www.dlsu.edu.ph

HTTPHypertext transfer protocol

- rules governing the delivery of web pages to theclient

�Understand

- Differentiate HTTP and HTML?

- HTML: hypertext markup languageDefinitions of tags that are added to Webdocuments to control their appearance.

- HTTP: hypertext transfer protocolThe rules governing the conversation between aWeb client and a Web server.

�Understand

- Differentiate HTTP and HTML?- HTML: hypertext markup languageDefinitions of tags that are added to Webdocuments to control their appearance.

�Understand

- Differentiate HTTP and HTML?- HTML: hypertext markup languageDefinitions of tags that are added to Webdocuments to control their appearance.

POP and SMTPPost Office and Simple Mail Transport Protocols

Server Message Block (SMB)Protocol

- supports file sharing in Microsoft-basednetworks

Gnutella Protocol- supports P2P services

Host-to-host (Transport) Layer

- parallels the functions of the OSI’s Transportlayer

- define protocols for setting up the level oftransmission service for applications.

- concerned with◦ reliable end-to-end communication◦ error-free delivery of data◦ packet sequencing

Transport Layer Role

Transport Layer Functions

- Enables multiple applications to communicateover the network at the same time on a singledevice

- Ensures that, if required, all the data isreceived reliably and in order by the correctapplication

- Employs error handling mechanisms- UDP- User Datagram protocol- an exchange ofdata w/o acknowledgment, sure delivery

- Employs error handling mechanisms

- UDP- User Datagram protocol- an exchange ofdata w/o acknowledgment, sure delivery

Transport Layer Purpose

- Segmenting data & managing each piece -data must be prepared to be sent across themedia in manageable pieces.

- Tracking the individual communicationbetween applications on the source anddestination hosts -maintains the multiple communication streamsbetween these applications.

- Segmenting data & managing each piece -data must be prepared to be sent across themedia in manageable pieces.

- Tracking the individual communicationbetween applications on the source anddestination hosts -maintains the multiple communication streamsbetween these applications.

- Reassembling the segments into streams ofapplication data -At the receiving host, each piece of data will bereconstructed and directed to the appropriateapplication.

- Identifying the different applications-assigns each application an identifier; theTCP/IP protocols call this identifier aport number.

- Reassembling the segments into streams ofapplication data -At the receiving host, each piece of data will bereconstructed and directed to the appropriateapplication.

- Identifying the different applications-assigns each application an identifier; theTCP/IP protocols call this identifier aport number.

Transport Layer Protocols

- Transmission Control Protocol (TCP)◦ Connection-oriented◦ Guaranteed Delivery◦ Supports Flow Control and Error control

- User Datagram Protocol (UDP)◦ Connectionless-oriented◦ Nonguaranteed Delivery◦ No Flow Control and Error control

Transport Layer Protocols

- Transmission Control Protocol (TCP)◦ Connection-oriented◦ Guaranteed Delivery◦ Supports Flow Control and Error control

- User Datagram Protocol (UDP)◦ Connectionless-oriented◦ Nonguaranteed Delivery◦ No Flow Control and Error control

Internet Layer

- corresponds to the OSI’s Network layer.

- designates the protocols relating to the logicaltransmission of packets over the entire network.

- concerned with◦ logical addressing, i.e. IP (Internet Protocol)address◦ routing of packets among multiple networks

Internet Layer

- corresponds to the OSI’s Network layer.- designates the protocols relating to the logicaltransmission of packets over the entire network.

Internet Layer

- corresponds to the OSI’s Network layer.- designates the protocols relating to the logicaltransmission of packets over the entire network.

Internet Layer

Internet Protocol (IP)Notes

Internet Protocol (IP)Connectionless

Internet Protocol (IP)Unreliable Protocol

Internet Protocol (IP)Media Independent

Internet Protocol (IP)- Segments are encapsulated as packets

Network Access Layer

- interface to the local network

- concerned with the exchange of data betweenan end system (server, workstation, etc.) andthe network to which it is attached.

- concerned with◦ hardware addressing◦ protocols for the physical transmission ofdata

- interface to the local network- concerned with the exchange of data betweenan end system (server, workstation, etc.) andthe network to which it is attached.

- the source and destination physical addressesare put on the front of the package in a partcalled the header.

- Information used to perform a frame checksequence on the message is placed at the backof the package in a section called the trailer.

- the package is converted to ones and zeros inthe format required by the physical medium inuse.

TCP/IP Data Encapsulation

- Application layer adds any requiredinformation concerning the presentation andformatting of the data to the header.

- Transport layer adds port number informationto the data that was handed down from theApplication layer.

- Internet layer adds the required logical addressinformation to the segment.

- Network Access layer adds physical addressinformation in the form of a frame header.

- Network Access layer also adds a frame trailerwhich contains information that can be used tocheck the integrity of the data, calledframe check sequence (FCS).

- Integrity means that the data has not changedeven 1 bit.

- Network adaptor converts the information intoa series of ones and zeros.

- At the beginning of the frame is a series of onesand zeros that are designed to allow thereceiving device to lock on to or synch up withthe signal.

- Once the receiving device has synched up withthe frame, it will start reading.

Protocol Operation of Sendingand Receiving

�Readings

In what year was it mandated that all computersconnected to the ARPANET use TCP/IP?

A. 1969B. 1974C. 1979D. 1983E. None of the above

�Readings

In what year was it mandated that all computersconnected to the ARPANET use TCP/IP?

A. 1969B. 1974C. 1979D. 1983 X

E. None of the above

TCP/IP Protocol SuiteNotes

Application Protocols- Telnet (Terminal emulation)allows a user on a remote client machine, calledthe Telnet client, to access the resources ofanother machine, the Telnet server.

- File Transfer Protocol (FTP)the protocol for transferring files

- Trivial File Transfer Protocol (TFTP)stripped-down, stock version of FTP; TFTPhas no directory-browsing abilities; it can donothing but send and receive files.

Application Protocols

- Network File System (NFS)allows two different types of file systems tointeroperate. Ex. NT and Unix file systems

- Simple Mail Transfer Protocol (SMTP)answering our ubiquitous call to email, uses aspooled, or queued, method of mail delivery.

- Line Printer Daemon (LPD)designed for printer sharing

Application Protocols- X Windowdefines a protocol for writing client/serverapplications based on a graphical user interface(GUI)

- Simple Network Management Protocol (SNMP)collects and manipulates valuable networkinformation. It gathers data by polling thedevices on the network from a managementstation at fixed or random intervals, requiringthem to disclose certain information.

Application Protocols

- Domain Name Service (DNS)resolves hostnamesâĂŤspecifically, Internetnames, such as www.dlsu.edu.ph.

- Dynamic Host Configuration Protocol(DHCP)/Bootstrap Protocol (BootP)assigns IP addresses to hosts. It allows easieradministration and works well in small to evenvery large network environments.

Host-to-host (Transport)Protocols

- Transmission Control Protocol (TCP)a full-duplex, connection-oriented, reliable, andaccurate protocol, but costly in terms ofnetwork overhead.

- User Datagram Protocol (UDP)a minimalist protocol mechanism with nohandshaking dialogues, thus exposes anyunreliability of the underlying network protocolto the user’s program. There is no guarantee ofdelivery, ordering or duplicate protection.

Internet Protocols

- Internet Control Message Protocol (ICMP)a management protocol and messaging serviceprovider for IP. Its messages are carried as IPdatagrams.

- Address Resolution Protocol (ARP)finds the hardware address of a host from aknown IP address.

Internet Protocols- Reverse Address Resolution Protocol (RARP)discovers the identity of the IP address fordiskless machines by sending out a packet thatincludes its MAC address and a request for theIP address assigned to that MAC address.

- Proxy Address Resolution Protocol (ProxyARP)help machines on a subnet reach remotesubnets without configuring routing or even adefault gateway.

Other Terms

- De facto standardone that becomes the standard simply by being the methodthat all parties gradually choose to use over a period oftime, without a formal adoption process.

- Default gatewayThis is the IP address of the nearest router in the network.

Other Terms

- IP addressa number in a specific format that is used to identify acomputer.

- ISO (International Organization for Standardization)is the world’s largest developer of voluntary InternationalStandards. International Standards give state of the artspecifications for products, services and good practice,helping to make industry more efficient and effective.Note: ISO is derived from the Greek isos, meaning equal.

Other Terms

- Local vs. RemoteIf the source and destination hosts are on the same network,the destination device is considered to be on the localnetwork.If the two computers are on different networks, thedestination device is considered to be on a remote network.

Other Terms

- Peripheralsare any devices that operate in conjunction with thecomputer yet reside outside the computer’s box. Ex.display, mouse, keyboard, printer, camera, speakers, andscanners.

- Resourcerefers to anything that a user on one computer may want toaccess on a different computer. Ex. files, folders, printers,and scanners.

- Telecommutingworking from another physical location, usually from home.

Other Terms

- Standard vs. ProprietaryProprietary refers to any process or way of doing somethingthat works only on a single vendor’s equipment whilestandard any process that the industry has agreed upon.

�Understand

- How do you ensure that products from differentmanufacturers can work together as expected?

- Answer:Using Standards which provide guidelines tomanufacturers, vendors, government agencies,and other service providers to ensure the kindof interconnectivity necessary in today’smarketplace and in internationalcommunications.

�Understand

- How do you ensure that products from differentmanufacturers can work together as expected?

- Answer:Using Standards which provide guidelines tomanufacturers, vendors, government agencies,and other service providers to ensure the kindof interconnectivity necessary in today’smarketplace and in internationalcommunications.

OSI Model and NetworkingDevices

�Networking andInternetworking Devices

�Networking andInternetworking DevicesExamples

Repeaters

- a physical layer device used to interconnect themedia segments of an extended network.

- does not actually connect two LANs; itconnects two segments of the same LAN.

Repeaters

- a physical layer device used to interconnect themedia segments of an extended network.

- does not actually connect two LANs; itconnects two segments of the same LAN.

Repeaters- repeaters regenerate signals corruptedprimarily due to distance effects

- A repeater forwards every frame; it has nofiltering capability.

Repeaters- repeaters regenerate signals corruptedprimarily due to distance effects

- A repeater forwards every frame; it has nofiltering capability.

HubMultiport repeater

- a physical-layer device that connects multipleuser stations, each via a dedicated cable

- used to create a physical star network whilemaintaining the logical bus or ringconfiguration of the LAN

HubMultiport repeater

- a physical-layer device that connects multipleuser stations, each via a dedicated cable

- used to create a physical star network whilemaintaining the logical bus or ringconfiguration of the LAN

Bridge

- A physical and data-link layer device that linksone LAN segment to others

- Read all frames transmitted on one LAN andaccept those address to any station on theother LAN

- Using MAC protocol for second LAN,retransmit each frame

Bridge

ReferencesTEXTBOOK:

- Data Communications and Networking,Behrouz Forouzan, 4th Edition, McGraw-Hill,2007

ReferencesSECONDARY SOURCE:

- Data and Computer Communications, WilliamStallings, 2007

- TCP/IP Protocol Suite, Behrouz Forouzan, 4thedition, 2010

- CISCO Networking Essentials, Troy McMillan,2012

- Network Fundamentals, Cisco NetworkingAcademy, 2007

Thank you for your attention!Notes

Data communication part1

Engineering

Transcript of Data communication part1

Sharing bisnis big data v3 part1

Electronic Communication & Data Communication

part1 · Collective Communication Part 2 - High-Performance MPI – Non-blocking Communication – Persistent Communication – User-deﬁned datatypes – MPI Idioms for High-performance

Machine Learning part1 - Introduction to Data Science

Data communication and communication Media

Data Structure Book Part1

Capcom13: GF4: Parler de la dépense publique : communication, impôts et gestion publique - part1

Chapter 2 Relational Data Model-part1

Modul Pengolahan Data (Part1)

บทที่ 6 การจัดการกับข้อมูล (Data Manipulation) Part1 ......บทที่ 6 การจัดการกับข้อมูล ...

Data Communication & Data Networking

Data structure unitfirst part1

24148273 Data Structure Book Part1

The Physical Layer Part1. The Theoretical Basis for Data Communication Fourier Analysis Bandwidth-Limited Signals Maximum Data Rate of a Channel.

DC Digital Communication PART1

INF3190 - Data Communication Data Link Layer · University of Oslo INF3190 – Data Communication INF3190 - Data Communication Data Link Layer Carsten Griwodz Email: griff@ifi.uio.no

Data Structures- Part1 overview and review

A Part1 Part1

Emona tims-analog-communication-part1 2

Cricket lost its song Part1 StudentB - Data Nuggets