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Lecture2
 

Lecture2

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    Lecture2 Lecture2 Presentation Transcript

    • What is CommunicationPeople have many ways to communicate:– Verbal/ non Verbal– Face to face/ over the telephone– Handwritten Letter– ChattingRequires Common Rules
    • The rules of communications are Protocol.Some of the protocols required forcommunication to occur include:- Sender & receiver- Method of communicating (face to face, phone,letter, photo and so on)- Language and Grammar- Speed & Timing of delivery- Confirmation / Acknowledgement requirements
    • Element of Network1. Rules / Agreement ( PROTOCOL): Rulesor agreement govern how the messages aresent, directed, received and interpreted.2. Message: The messages or unit of informationtravel from one device to another.3. Medium: a means of interconnecting devices,a medium can transport the messages from onedevice to another.4. Device: devices on the network exchangemessages with each other
    • Early networks had varying standards and asa result could not communicate easily witeach other.People use many technologies and devicesthat they do not understand.Computer networks are similar.Two people communicating on end devicesin different networks can do so only if manycomplex processes are succesfullycompleted.
    • MessageMessage:The messages or unit of information travelfrom one device to another.Message is a generic term that encompassesweb pages, email, instant messages,telephone calls & other form ofcommunication.The message must be one that the networkcan carry.
    • The messages must be supported in softwareat the end device.It does not matter whether the message is:text, voice, or video because all form areconverted into bits, binary-coded digital signals,to be carried over a wirelles , copper, or fiberoptic connection.The digital signal can change with the media, butthe original message content will remain intact.
    • MediumMedium that physically carries the messagecan change several times between thesender & receiver.Network connections can be wired orwirelless.
    • In wired connections the medium is eithercopper with electrical signals or optical fiberwith light signals.The copper medium includes cables :twisted pair telephone wire, coaxial cable, orCategory 5 unshielded twisted pair (UTP)Optical fibers, thin strands of glass or plasticthat carry light signals
    • UTP Cat 5
    • In wirelles connection the medium is:Earths atmosphere / space, and thesignals are microwave.Wireless media can include the homewireless connection between a wirelessrouter & computer with wireless networkcard, the terrestrial wireless connectionbetween 2 ground stations, or thecommunication between devices on earth &sattelite
    • DevicesMany devices : switch and router, work to seethe message is properly directed from thesource (originating device) to thedestination device.At the destination network there can be moreswitches, cable or wireless router that willdeliver the instant message to the receiver.
    • RulesAs communication process happen, tens ofthousands of process can happen in asingle second.To work properly, the network process mustbe controlled. Rules govern every step ofthe process, from the way cables aredesigned to the way digital signals are sent.These rules are called Protocols
    • RulesMost common:TCP Transmission Control ProtocolIP Internet ProtocolService Protocol / RuleWWW Hyper Text TransferProtocolEmail SMTP and POPInstant Message XMPP & OSCARIp Telephony SIP
    • Network ArchitectureSyarat-syarat desain yg baik:− Fault Tolerance− Scalability− QoS (Quality of Service)− Security
    • Fault ToleranceFault tolerance:Sistem harus tetap berjalan meskipunbeberapa komponen mengalamikegagalan.Key Factor: -Redundancy:Duplikasi peralatan & media
    • Fault Tolerant NetworkArchitectureCircuit-Switched− Connection-Oriented NetworksPacket-Switched− Connectionless NetworksMessage –block of data - Packets
    • ScalabilityKemampuan network untuk tumbuh danbereaksi terhadap perubahan masamendatang.
    • Scalable Network ArchitectureScalable network mampu untuk tumbuhtanpa adanya perubahan fundamental padainti /core.Contoh:Internet is a collection of many private and publicnetwork interconnected by routers.
    • Quality of Service (QoS)Menunjukkan performance level dari serviceyang ditawarkan melalui network.Eg:Live Video or Voice dapat memerlukan lbhbanyak resource drpd email.Because many techs are converged onto 1platform, the separation of types of serviceson that platform can allow higher priority forone service over another.
    • Menyediakan QoSQos :Mengacu kpd mekanisme yang mengaturcongested network traffic.Congestion is caused when the demand onnetwork resource exceeds the availablecapacity.Network bandwidth is the measure of thedata-carrying capacity of the network.With Qos, the manager can manage thepriority.
    • Network SecurityMenjadi esential ketika publik hrs mempunyairasa aman ketika mengakses internet.Contoh:Melakukan financial transaction.- Untukpersonal information memerlukan privasimelalui:- Encripted messages.- Security devices to control network access.
    • Providing Network Security1. Securing the Network Infrastructuremeans: protecting the devices from outsidecontactContoh: -locking computer room door,password protection.2. Securing the Network Content means:protection of data stored on networkdevices & the protection of packets carryinddata into or out of the network.
    • CIA1. Confidentiality2. Integrity3. Availability
    • Ensuring ConfidentialityData privacy is maintained by allowing onlythe intended and authorized recipient-individual, proces, or device to read thedata.Biasanya: User Authentication,-Menggunakan password yang susahditebak.-Mengganti password secara berkala.
    • Maintaining CommunicationIntegrityData integrity means:Menjamin bhw informasi tidak di Alter dalampentransmisiannya dari origin ke destinasi.Informasi dikorupsi secara sengaja atau taksengaja sblm sampai tujuan.Source Integrity:Adalah jaminan bahwa identitas sender sdhdivalidasi. User or device fakes the identity& supply inccorect information to recipient.
    • Ensuring AvailabilityMeyakinkan bahwa resource tersedia kepadaauthorized user / pemakai.Contoh:Serangan virus komputer, Denial of Service(DoS) dpt membuat network menjadi Down.Tools:-AntiVirus SoftWare-Firewall: analyze traffic enterring and exitinga network.