Aplikasi Jaringan 2
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Transcript of Aplikasi Jaringan 2
Pertemuan 1 / Sesi 1Motivation dan Introduction
to Telecommunication & Computer Networks
Email: [email protected]
Deff Arnaldy, M.Si
Courtesy:Bagian Net-Centric ComputingFaskultas Sains dan TeknologiUniversitas Islam Negeri Jakarta (UIN)
Agenda
Overview dan Klasifikasi JaringanOverview OSI dan TCP/IPManajemen, Desain, dan Kinerja Tradisional
(“How not to manage a network”)Kinerja, Disain, dan ManajemenMetode-metode Analisis KinerjaContoh-contoh
Diharapkan Anda dapat…1)
menjelaskan klasifikasi jaringan komputer/telekomunikasi skema mode komunikasi cara kerja ethernet (CSMA/CD) cara kerja perangkat intermediate system arsitektur lapisan OSI dan TCP/IP
Diharapkan Anda dapat…2)
menyebutkan landasan teori dan motivasiEvaluasi Kinerja (Performance evaluation)Teknik Disain Sistematis (Systematic design techniques)Manajemen Jaringan (Network management)
menggambarkan dan menyebutkan contoh 3 model sistem jaringanResource sharing networksProcess networksSwitching networks
Diharapkan Anda dapat…3)
mendaftarkan dan menggambarkan 3 tipe metode studi kinerja jaringan dan karakteristiknyaAnalyticalSimulationMeasurementsMendaftarkan langkah-langkah dasar dalam studi kinerja jaringanMenerapkan langkah-langkah tersebut untuk merumuskan sebuah studi kinerja jaringan pada sistem dan tujuan yang telah diberikanMendefinisikan perbedaan antara Validasi dan Verifikasi
Ganjil - November 2007/2008 6Perkembangan TIK (Bagian I)
Klasifikasi Jaringan
Communication Network
SwitchedCommunication
Network
BroadcastCommunication
Network
Circuit-SwitchedCommunication
Network
Packet-SwitchedCommunication
Network
Datagram Network
Virtual Circuit Network
PSTN, ISDN
Ethernet, Token Ring, FDDI, etc.
ATM, Frame Relay, X.25, etc.IP
Klasifikasi Jaringan
Jaringan telekomunikasi dapat diklasifikasikan berdasarkan bagaimana sinyal ditransmisikan dan diterimabroadcastswitched
•Jaringan broadcastsinyal yg ditransmisikan oleh satu peralatan end-user secara otomatis didengar oleh semua peralatan end-user lainnya
•Switched networkssinyal harus dirutekan melalui node jaringan atau di-switch ke rute yg diinginkan
Klasifikasi Jaringan
Node jaringan mempunyai berbagai nama yg berbeda:Data Circuit Terminating equipment (DTE) - ITU-TInterface Message Processor (IMP) - ARPANETSwitch - jaringan teleponRouter - LANdsb
Peralatan user biasa disebut Data Terminal Equipment (DTE) - ITU-T :terminaltelepon sethostPCworkstation, dll
Klasifikasi Jaringan
•HybridTipe jaringan telekomunikasi ini merupakan gabungan dari broadcast dan switched networkmisalnya: segment Ethernet (broadcast) dihubungkan dengan Router
Broadcast vs Switched Networks
Broadcast
Hybrid
Switch
Klasifikasi Jaringan
Jaringan juga dapat diklasifikasikan berdasarkan cakupan geografisnya:
Local Area Network (LAN) :
dibatasi beberapa Km, kantor atau kampusMetropolitan Area Network (MAN)
puluhan Km, kotaWide Area Network (WAN)
ratusan - ribuan KmTerrestrial radio networks
Wireless communications
Satellite networks - internasional
Klasifikasi Jaringan Lainnya
Cara Pengontrolan: Centralized vs. Distributed
Kepemilikan: Publik, Private
Tipe Transmisi: Voice, data, video
Teknik Transmisi: Analog, digital, radio, satelit
Topologi: Mesh (mata jala), bus, ring, star, tree
Laju Data/Kecepatan Respon: Broadband / Narrowband
Media: Single media (seperti: Telepon) , Multi media (seperti: Broadband ISDN)
Ganjil - November 2007/2008 14Perkembangan TIK (Bagian I)
Skema Pengiriman Data
Routing merupakan proses pemilihan jalur (path) dalam sebuah jaringan selama pengiriman data atau lalu-lintas (trafik) fisik.Jaringan (network) di sini meliputi jenis jaringan apa saja termasuk telephone network, Internet, dan transport networks.Routing | Rute | Skema Pengiriman Data:UnicastBroadcastMulticastAnycast
Ganjil - November 2007/2008Perkembangan TIK (Bagian I) 15
Unicast
unicast adalah proses pengiriman paket informasi ke sebuah tujuan tunggaldisebut juga komunikasi point-to-point.
Ganjil - November 2007/2008Perkembangan TIK (Bagian I) 16
Broadcast
broadcasting adalah proses pengiriman paket informasi ke segala tujuan (node, peralatan) dalam sebuah jaringan
Ganjil - November 2007/2008Perkembangan TIK (Bagian I) 17
Multicast (atau Multiplexed Broadcast)
Multicast merupakan sebuah mekanisme pengiriman informasi ke sebuah grup dalam sebuah jaringan,Biasanya pesan hanya dikirim sekali pada setiap link jaringan dan dicopy (gandakan) ketika link tujuan terbagi (split)
Ganjil - November 2007/2008Perkembangan TIK (Bagian I) 18
Anycast
Anycast merupakan sebuah skema pengalamatan dan perutean is a network addressing and routing scheme di mana data dirutekan ke tujuan terdekat (terbaik)
Ganjil - November 2007/2008Perkembangan TIK (Bagian I) 19
Tambahan: Komunikasi Broadcast
Broadcast address, an IP address allowing information to be sent to all machines on a given subnetBroadcasting (computing), transmitting a packet that will be received by every device on the networkBroadcast domain, a logical area where any computer connected to the network can directly transmit to any other
Ganjil - November 2007/2008Perkembangan TIK (Bagian I) 20
EthernetHistory
"The diagram ... was drawn by Dr. Robert M. Metcalfe in 1976 to present Ethernet ... to the National Computer Conference in June of that year. On the drawing are the original terms for describing Ethernet. Since then other terms have come into usage among Ethernet enthusiasts."Just as a reminder: in 1976, INTEL had just developed the 8080, which was running at an unbelievable speed of 4.77 MHz !!!
Ganjil - November 2007/2008Perkembangan TIK (Bagian I) 21
Sabtu, 7 April 2007Computer Network Analysis - Review ICT 22
Broadcast Networks
Sabtu, 7 April 2007Computer Network Analysis - Review ICT 23
Protokol IEEE 802.3: Ethernet
CSMA/CDCarrier Sense Multiple Access / Collision DetectionCarrier SenseSebelum sistem memulai pengiriman data ke networkCek kabel (media transmisi), apakah ada sinyal carrier (ada pengiriman data lain)? *)
YES: tunggu sampai pengiriman selesaiNO: sistem langsung mulai mengirimkan data*) mirip seperti kita saat mengangkat telepon dan mendengarkan suara dial-tone
Sabtu, 7 April 2007Computer Network Analysis - Review ICT 24
Protokol IEEE 802.3: Ethernet
CSMA/CDCarrier Sense Multiple Access / Collision Detection
Multiple AccessSelama tidak ada ‘sinyal sibuk (carrier)’ pada kabel, semua node yang terkoneksi ke network dapat segera memulai mengirimkan data
Collision DetectionJika ada ≥ 2 node mengirimkan data bersamaan Signal CollisionProtokol mendeteksi collision sinyal saling mengganggu satu sama lainstop pengiriman memaksa semua node untuk back-offTunggu beberapa saat (secara random) back-off algorithmLakukan mekanisme CSMA lagi
Mekanisme CSMA
Mekanisme CSMA/CD
Sabtu, 7 April 2007Computer Network Analysis - Review ICT 27
Signal Collision
≥ 2 signal carrier bertemu dan saling menginterferensi
Sabtu, 7 April 2007Computer Network Analysis - Review ICT 28
Repeater, Hub, Bridge, Switch
Hub, RepeaterLAN basedWorks based on Ethernet (IEEE 802.3) protocolCSMA/CD mechanismNon-intelligent (Stupid) Device ;)InexpensiveEasy to installUnconfigurable, unmanageable1 domain collisionworks on Layer 1
Sabtu, 7 April 2007Computer Network Analysis - Review ICT 29
BridgeLAN basedWorks based on Ethernet (IEEE 802.3) protocolCSMA/CD mechanismIntelligent (Smart) Device ;)More expensiveEasy to installconfigurable, unmanageable> 1 domain collisionworks on Layer 2
Repeater, Hub, Bridge, Switch
Sabtu, 7 April 2007Computer Network Analysis - Review ICT 30
Repeater, Hub, Bridge, Switch
SwitchLAN based, Internet BasedWorks based on Ethernet (IEEE 802.3) protocolCSMA/CD mechanismIntelligent (Smarter) Device than Bridge ;)More expensive than BridgeEasy to installconfigurable, manageable> 1 domain collision (each port has domain collision)works on Layer 2
Sabtu, 7 April 2007Computer Network Analysis - Review ICT 31
Switched Networks
Ganjil - November 2007/2008 32Perkembangan TIK (Bagian I)
Sabtu, 7 April 2007Computer Network Analysis - Review ICT 33
Service - menyatakan apa yang dilakukan suatu layerInterface – menyatakan bagaimana mengakses serviceProtokol - menyatakan bagaimana service diimplementasikanProtokol - satu set aturan yang mengatur komunikasi di antara peers yang berkomunikasiSyntax: menentukan format informasi yang dikomunikasikanSemantic: arti dari sinyal yang dipertukarkanTiming: kapan data ditransmisikan/dilihat, ururtan informasi, matching kecepatan, dll.Protocol diperlukan untuk interaksi diantara peers
Protocol stack: satu set protocol layersTiap layer menggunakan layer di bawahnya dan menyediakan service ke layer di atasnya
Konsep Model OSI
Sabtu, 7 April 2007Computer Network Analysis - Review ICT 34
Fungsi Setiap Layer OSI
Presents the interface to the user to access the provided functionality.
Higher layers
Presentation
Lower layers
Application
Session
Transport
Network
Data link
Physical
Formats the data
Controls a communications link between two hosts (open, manipulate, and close)
Provides data transfer services (either reliable or unreliable)
Provides an addressing mechanism between hosts and also routes packetsControls the physical communication link between two hosts. Also responsible for shaping the data for transmittal on the physical medium.The physical medium responsible for sending data as a series of electrical transmissions.
Sabtu, 7 April 2007Computer Network Analysis - Review ICT 35
Skenario komunikasi dan fungsi utama masing-masing layer
Application
Presentation
Session
Transport
Network
Datalink
Physical
Application
Presentation
Session
Transport
Network
Datalink
Physical
Network
Datalink
Physical
Physical medium
User service
Transformation of encoding
Dialog control
End-to-end reliability
Route set-up
Error control, access control
Interface to medium
Hig
he
r la
yers
Lo
we
r la
yers
Open System Interconnection (OSI)
Sabtu, 7 April 2007Computer Network Analysis - Review ICT 36
Proses pembentukan dan pembuangan protocol headers Encapsulation, Fragmentation, Reassembly
data
data
data
data
data
data
data
data
data
data
data
data
data
data
Encapsulation, MTU, Fragmentation, Reassembly, Datagram Size
Sabtu, 7 April 2007Computer Network Analysis - Review ICT 37
Concatenation of Networks
Protocol Stack
R2
R1
H4
H5
H3H2H1
Network 2 (Ethernet)
Network 1 (Ethernet)
H6
Network 3 (FDDI)
Network 4(point-to-point)
H7 R3 H8
R1
ETH FDDI
IPIP
ETH
TCP R2
FDDI PPP
IP
R3
PPP ETH
IP
H1
IP
ETH
TCP
H8
IP Internet
Sabtu, 7 April 2007Computer Network Analysis - Review ICT 38
MTU ~ Maximum Transmission Unit
Maksimum jumlah data yang dapat di’bawa’ oleh teknologi hardware networkKarakteristik Network HardwareTidak dirancang untuk menerima/mengirim frame ‘melebihi’ MTUUkuran Data ≤ MTUJika Ukuran Data > MTUDatagram tidak dapat dienkapsulasiDatagram tidak akan dikirim
Header overhead for Various Protocol Information Frames
Ganjil - November 2007/2008Perkembangan TIK (Bagian I) 39
Protocol Overhead Max Frame Size Description(bytes) (bytes)
Ethernet 18 1518 6 source, 6 destination 2 type, 4 CRC
IEEE 802.3 21 1521 6 source, 6 destination 2 length, 3 LLC, 4 CRC
IEEE 802.5 Token Ring
28 4472 & 79006 source, 6 destination 4 misc., 3 LLC, 5 802.2 SAP, 4 CRC Up to 16 source-routing octets may be added
FDDI (RFC 1390) 28 45003 802.2 LLC, 5 802.2 SNAP, 4 source, 4 dest, 4 misc., 8 FCS. The source and dest addr may be 12 bytes
ATM (RFC 1483) 8 534 CRC, 2 length, 1 CPI, 1 CPCS-UU. For AAL-5 multiprotocol encapsulation. The ATM cell header is only 5 bytes
FR (RFC 1490) 8 NA 2 flags, 2 Q.922 addr, 1 control, 1 NLPID, 2 FCS. For multi protocol encapsulation.
PPP (RFC 1662) 10 NA 8 HDLC framing, 2 PPP protocol itself
HDLC 8 NA 1 flag, 1 addr, 1 control, 4 CRC, 1 flag
TCP (RFC 793) 20 65535 8 seq number, 4 ports, 2 win, 6 other. RFC 1106 extends the win size to over 1 GB
IP (RFC 791) 20 65535 8 IP addr, 12 other
Sabtu, 7 April 2007Computer Network Analysis - Review ICT 40
Ilustrasi MTU
H1 terhubung ke jaringan yang memiliki MTU=1500 octets (bytes)H2 terhubung ke jaringan yang memiliki MTU=1000 octets (bytes)H1 R X H2
H2 R H1
H1 H1RNet 1 (MTU=1500)
Net 2 (MTU=1000)
1500
Sabtu, 7 April 2007Computer Network Analysis - Review ICT 41
Solusi: Fragmentation & ReassemblySetiap network punya harga MTUStrategifragment jika diperlukan (MTU < Datagram)Usahakan mencegah fragmentation pada source hostre-fragmentation dimungkinkanfragments adalah self-contained datagramstunda reassembly sampai destination hostTidak melakukan recover dari fragments hilang
Bagaimana Jika Data > MTU
Sabtu, 7 April 2007Computer Network Analysis - Review ICT 42
Ilustrasi MTU
H1 terhubung ke jaringan yang memiliki MTU=1500 octets (bytes)H2 terhubung ke jaringan yang memiliki MTU=1000 octets (bytes)H1 R mem-fragment data ke H2
H2 R H1
H1 H1RNet 1 (MTU=1500)
Net 2 (MTU=1000)
1500 1000500
Observasi
Dengan kemajuan dlm kecepatan transmisi, total delay didominasi oleh delay propagasi dg batas atas kecepatan cahaya
Circuit switching menambahkan ekstra roundtrip delay dibandingkan datagram packet switching, tetapi menghilangkan delay store-and-forward
Ada dua kasus:jika link lambat bottleneck ada pada kecepatan transmisi link. Delay store-and-forward cukup berarti. Penambahan ekstra roundtrip delay tidak berarti circuit switching (total delay )Jika link cepat bottleneck ada pada delay propagasi. Penambahan roundtrip cukup berarti. Delay store-and-forward delay tidak cukup berarti packet switching (total delay )
Pertemuan 1 / Sesi 2Motivation dan Introduction
to Telecommunication & Computer Networks
Email: [email protected]
Deff Arnaldy, M.Si
Courtesy:Bagian Net-Centric ComputingFakultas Sains dan TeknologiUniversitas Islam Negeri Jakarta (UIN)
Algorithm untuk Kerja Jaringan1)
Contoh kerja sebuah LAN untuk Aplikasi Intranet Klien/Server
1. deploy LAN based on current technology and constrained by budget;
2. do {3. while (no complaints) { surf the web }4. surf to a trade magazine site;5. buy latest technology constrained by
budget;6. deploy latest technology;7. if (key users not happy) { increase
budget and go to 5 }8. } while (still employed)
Algorithm untuk Kerja Jaringan2)
Kendati pendekatan tadi sangat jauh dari optimalisasi kerja sebuah jaringan, namun terdapat relasi antara evaluasi, disain, dan manajemen:Management: Note the lack of user complaintsEvaluation: Ascertain the reason for the whiningDesign: Buy some stuff and make it work
Masalah-masalah:Likely to spend too muchExcessive periods of poor performanceProblem may not be fixedResponding to perception, not reality
Algorithm untuk Kerja Jaringan1)
Contoh kerja sebuah LAN untuk Aplikasi Intranet Klien/Server
1. deploy LAN based on current technology and constrained by budget;
2. do {3. while (no complaints) { surf the web }4. surf to a trade magazine site;5. buy latest technology constrained by
budget;6. deploy latest technology;7. if (key users not happy) { increase
budget and go to 5 }8. } while (still employed)
Evaluation
Relasi antara Kinerja, Disain, dan Manajemen Jaringan
DisainJaringan
ManajemenJaringan
Evaluasi/AnalisisKinerja
Evaluasi/Analisis Kinerja
We can predict the behavior of networks “using pencil, paper, the poetry of mathematics and the number-crunching ability of computers.”(T. Robertazzi)Peralatan Evaluasi/Analisis KinerjaTeori Peluang dan Teori AntrianModel-model TrafikSimulasi
Disain
“A network design is a blueprint for building a network. The designer has to create the structure of the network [and] decide how to allocate resources and spend money.”
(R. Cahn)
Peralatan Disain:Teknik-teknik Pekerjaan berkaitan dg KapasitasTeori GraphComputer-aided design tools (e.g.: AutoCAD, Visio, etc.)
Manajemen
“… our only real option is to use the network to manage the network. This means we need a protocol that allows us to read, and possibly write, various pieces of state information on different nodes.” (L. Peterson & B. Davie)
Peralatan ManajemenProtokol-protokol Manajemen, e.g.: SNMPManagement tools, e.g.: netstatEksperimen (Percobaan)
Model-model Jaringan
Apa yang sedang kita modelkan?
Secara umum, kita memodelkan jaringan untuk 3 kategori berikut:Resource sharing networksProcess networksSwitching networks
Resource sharing networks1)
Time-shared computer (Programs : CPU/Disk/IO)
Statistical multiplexer/concentrator
Packet-based (Packets : Links)
Channel-based (Calls : Channels)
Multiple-Access and random access networks (Packets: Shared Medium)
USER 1
USER N
SharedResources
Resource sharing networks2)
Kinerja Jaringan yang diukur (metrics):Waktu tunggu (Waiting time)Peluang Blocking (Blocking probability)
Pertanyaan kita sekarang adalah:Bagaimana hubungan antara User, Pola Penggunaan, Jumlah Kebutuhan Resources dan Kinerja Jaringan?Apakah setiap User menggunakan Resources secara “ADIL”?
Process Networks1)
Multi-stage switch
Distributed simulation system
Manufacturing process
Input 1Input 1
Input 2Input 2
Input 3Input 3
Input 4Input 4 Process 5Process 5
Process 2Process 2
Process 1Process 1
OutputOutput
Process Networks2)
Kinerja Jaringan yang diukur (metrics):Waktu Penyelesaian (Time to complete ~ delay)Throughput (completions per unit time)
Pertanyaan kita sekarang adalah:Bagaimana kinerja dapat dipengaruhi oleh Pola-pola Penggunaan yang berbeda?Proses-proses mana yang merupakan “bottlenecks” yang merupakan Batasan Kinerja Jaringan?Apakah input yang berbeda diperlakukan secara ADIL berkenaan dengan Kinerja Jaringan?
Switching Networks1)
Telephone network (Phones : Circuit Switches)Telephone signaling network (Switches : STPs)X.25 packet network (Computers : Packet Switches)Internet (Computers : Routers)
EndpointEndpoint
EndpointEndpoint
SwitchSwitch
SwitchSwitch
Process 5Process 5
SwitchSwitch
EndpointEndpoint
EndpointEndpoint
Switching Networks2)
Kinerja Jaringan yang diukur (metrics):Delay (endpoint to endpoint)ThroughputUtilizationBlocking probabilityLosses
Pertanyaan kita sekarang adalah:Bagaimana Topologi yang terbaik?Bagaimana kita melakukan perutean?Bagaimana kita menjamin QoS?
Analisis Kinerja1)
Why?Bottleneck atau analisis kapasitasSensitivitas (Kepekaan) dari kinerja parameter-parameterMendeteksi lingkup masalah untuk memandu system tuningPerencanaan konfigurasi dan trade-offsBenchmarking
When?Arsitektur atau Desain SistemDesain dan Implementasi DetailOperasional
Analisis Kinerja2)
How?Analytical models, e.g., queuing models with closed form or numerical solutionsSimulation experiments, e.g., discrete-event simulation with statistical resultsEmpirical measurements, e.g., instrumented code and network monitoring
Pendekatan Sistematis1)
Sebutkan ‘goals’ dari studi dan definisikan sistem yang akan dianalisisSket batasan-batasan sistem‘Goals’ akan menentukan batasan-batasan yang sesuai
Daftarkan layanan/fungsi dan hasil dari layanan tersebutPilih ukuran/satuan (metrics) yang akan dianalisisContoh: throughput, latency, availability, etc.
Buat daftar parameter-parameter yang mempengaruhi kinerja (performance)Parameter-parameter SistemParameter-parameter Beban Kerja (Workload)
Pendekatan Sistematis2)
Pilih faktor-faktor yang menjadi studi (akan diteliti)Faktor-faktor merupakan parameter-parameter yang mungkin akan bervariasiParameter-parameter lainnya akan ditetapkan
Pilih teknik evaluasiAnalitik (Analytical) -> Formula Erlang’s BlockingSimulasi (Simulation) -> Simulasi dengan NS2Pengukuran (Measurement) -> Worst-case Analysis
Pilih beban kerja (workload) atau daftar permintaan layananProbability distributions for analytical studyTrace or distribution for simulation studyScripts for measurements
Next
Contoh Teknik Evaluasi Analitik:: Traffic intensity ::
In telephone networks:
Traffic ↔ Calls
The amount of traffic is described by the traffic intensity aDefinition: the traffic intensity a is the product of the arrival rate and the mean holding time h:
a = h
Note that the traffic intensity is a dimensionless quantity. However, to emphasize the context, the “unit” of the traffic intensity a is called erlang (erl)
By Little’s formula: the traffic intensity tells the number of ongoing calls in the corresponding (hypothetical) infinite system.
Back
Example
Consider a local exchange. Assume that,on the average, there are 1800 new calls in an hour, andthe mean holding time is 3 minutes
It follows that the traffic intensity isa = 1800 3/60 = 90 erlang∗
If the mean holding time increases from 3 minutes to 10 minutes, then
a = 1800 10/60 = 300 erlang∗
Back
Traffic characteristic
Here are typical characteristic traffics for some subscriber categories (of ordinary telephone users):private subscriber: 0.01 - 0.04 erlangbusiness subscriber: 0.03 - 0.06 erlangprivate branch exchange (PBX): 0.10 - 0.60 erlangpay phone: 0.07 erlang
This means that, for example,a typical private subscriber uses from 1% to 4% of her time in the telephone (during a “busy hour”)
Referring to the previous example, note thatit takes between 2250 - 9000 private subscribers to generate 90 erlang traffic
Back
Contoh Teknik Evaluasi Analitik :: Erlang’s formula ::
Then the quantitive relation between the three factors (system capacity, traffic load and quality of service) is given by the Erlang’s formula
Note: n! = n (n-1) (n-2) … (2) (1), 0! = 1
Other names:Erlang’s blocking formulaErlang’s B-formulaErlang’s loss formulaErlang’s first formula
Back
Example
Assume that there are n = 4 channels on a link and the offered traffic is a = 2.0 erlang. Then the call blocking probability Bc is
If the link capacity is raised to n = 6 channels, then Bc reduces to
Back
Contoh Teknik Evaluasi Simulasi :: Network Simulator 2 ::
Parameter: kapasitas = 2 Mbps, delay = 10 ms
Protokol: TCP; Layanan: FTP
Performance Metric: Throughput, Connection-oriented Protocol
Komputer A(Sender)
Komputer B(Receiver)
C = 2 Mbps, Delay = 10 ms
Layer 4: TCP Reno
Aplikasi FTP
Script Program
Back
Network Properties and Time BudgetDocument size = 800 KbyteTo be copied from a file server at the hub site to a workstation at a spoke siteDocument transfer over Frame Relay NetworkWe have initial speed:1,544 Kbps port speed at the Hub site56 Kbps port speed at the Spoke site
Lets vary the hub port speed!
Contoh Teknik Evaluasi Measurement:: Document Retrieval over FR Network ::
Worst-case Analysis example
Back
Pendekatan Sistematis3)
Desain percobaan/eksperimenPhase 1: Large number of factors, few valuesPhase 2: Small number of factors, many values
Analisa dan interpretasikan hasilnyaResults are randomStatistical techniques needed to compare results
Presentasi HasilGraphical techniquesRefinement and iteration may be needed
Teknik-teknik Evaluasi
HighMediumLow“Sale ability”
HighMediumLowCost
DifficultModerateEasyTrade-off Evaluation
VariesModerateLowAccuracy
VariesMediumSmallTime required
Post-prototypeAnyAnyStage
MeasurementSimulationAnalyticalCriterion
Contoh: ISP1)
Sebuah ISP menyediakan akses circuit-switched (saluran telepon PSTN) ke InternetBerapa banyak saluran (koneksi aktif simultan maksimum) yang harus kita sediakan?Kepuasan Pelanggan Large number of lines to reduce probability of blocking (busy)Biaya Operasi Small number of lines to reduce equipment, line, maintenance, and power costs
Kapan saluran baru harus disediakan?Apa toleransi terhadap Kepuasan Pelanggan dan biaya operasi?
Contoh: ISP2)
Kebijakan apa yang harus dibuat untuk memaksimumkan keuntungan/profit?Charge a flat fee or charge for connect time?Limit sessions to X hours?Automatically disconnect inactive users after Y minutes?Differentiate service based on price?
Pertanyaan-pertanyaan berikut mendefinisikan TUJUAN dan SISTEM untuk studi kinerja jaringan:Management information needed for the studyResults of study can be applied to optimize design of modem pool (and policies)
Contoh: ISP3)
DisainJaringan
ManajemenJaringan
Evaluasi/AnalisisKinerja
Effect ofnumber of linesand polices onperformance
Workloadcharacteristicsand currentperformance
Optimized modempool and polices
Contoh: ISP4)
Ingat bahwa model ini merupakan sebuah “resource sharing network”Users must share a limited number of linesNumber of users exceeds the number of linesIf number of active users equals the number of lines, further use attempts by other users will be blocked
USER 1
USER N
SharedResources
Contoh: ISP5)
MetricsBlocking probabilityWait time (until a line is free)
System parametersNumber of lines
Workload parametersNumber of calls (arrival or attempt rate)Length of call (holding or service time)Time until retry attempt if blocked
Factors to vary for the studyNumber of linesNumber of users (attempt rate)
Contoh: ISP6)
Evaluation techniquesAnalytical (Erlang model)Measurement of specific configuration(s) to validate analytical results
Select workloadsAssumptionsHolding timeProbability of an attempt from a userRetry characteristicsAssumptions can be developed by monitoring use patternsRequires network management (monitoring)
Contoh: ISP7)
Design and conduct experimentsEasy for analytical studyMore difficult for measurements
Analyze and interpret resultsAgain, easy for analytical study and more difficult for measurements
Present resultsValidation of analytical results using measurements increases confidence in results
Validasi vs. Verifikasi
Verification (usually easy to do)Is the model properly constructed?Analytical model: “Is the math right?”Simulation model: “Is the model properly coded?”
Validation (often hard to do)Does the model accurately represent the behavior of the system of interest?Analytical model: “Is the model ‘correct’?”Simulation model: “Is this an accurate simulation for the questions of interest?”
Contoh: Layanan Backbone1)
A carrier provides backbone services to companies and lower-tier ISPsInternet access to companies and ISPsVirtual private network (VPN) service for corporate networks
Contoh: Layanan Backbone2)
This is a “switching network”Customer networks are endpointsIP routers in the backbone are switches
Backbone network defines system boundary
Contoh: Layanan Backbone3)
Throughput objectives – relatively simpleMaximize network throughput given a maximum cost constraintMinimize cost given a minimum throughput constraint
Throughput factorsNetwork topologyLink capacityRouter capacityRouting algorithm (efficiency)Workload (characteristics of traffic leaving customer networks)
Contoh: Layanan Backbone4)
Network managementIdentify problemsBottlenecksRouting problemsMisbehaved customer networksLink and router failuresMonitor traffic to model workload
Performance evaluationStudy affects of network design changesStudy affects of workload changesIdentify bottlenecksProactive planning for network grown
Contoh: Layanan Backbone5)
Network designAdjust link capacity, router capacity, and topologyOptimize routing
DisainJaringan
ManajemenJaringan
Evaluasi/AnalisisKinerja
? ?
?
Contoh: Layanan Backbone6)
Quality of service (QoS) or service level agreement (SLA) objectives – relatively complexGuaranteed throughput over some period of timeMaximum delayMaximum delay variationAvailability
Customer network issues imply need for network managementMonitoring service level agreementsPolicing traffic
Contoh: Layanan Backbone7)
Backbone network issuesTo what set of SLAs can a carrier commit with a given set of network resources?How to optimize the network for a given set of SLAs?How much to charge for a given SLA?How to optimize revenue?
Management, performance evaluation, and design must be considered to optimize the network operation (and revenues)
Contoh: Packet Switch Design1)
An equipment vendor is designing a high-performance Layer 3 IP switch
Contoh: Packet Switch Design2)
This system is a “process network” if implemented as a multi-stage switch
Contoh: Packet Switch Design3)
This system is a “resource sharing network” if implemented as a TDMA bus
Contoh: Packet Switch Design4)
There are many performance issuesAggregate and per port throughputInput-to-output delayIntroduced delay variation (jitter)Blocking probabilityPacket loss due to queue overflowReliability
Contoh: Packet Switch Design5)
There is not an operational system to manage (monitor), so the process involves just …DesignPerformance (and cost) evaluation
DisainSistem
EvaluasiKinerja
Contoh: MAC Protocol Design1)
A researcher is developing a new multiaccess control protocol for a wireless ad hoc network
This is a “resource sharing network”Stations (e.g., A, B, and C) are the usersRadio spectrum is the shared resource (medium)
Contoh: MAC Protocol Design2)
There are many performance issuesSystem throughputPacket delayAllocation of system throughput (fairness)Channel utilizationProbability of collision
There are a number of factors affecting performanceOffered trafficNumber of stations (and placement)Channel characteristicsProtocol operation
Contoh: MAC Protocol Design3)
And, there are many design issues …How to share the spectrum?Circuit-switched schemesFrequency division multiple access (FDMA)Time division multiple access (TDMA)Code division multiple access (CDMA)Packet-switched time division multiplexed (TDM) schemesReservation-based TDM schemes, e.g., packet reservation multiple access (PRMA)Contention-based TDM schemes, e.g., carrier sense multiple access (CSMA)
Contoh: MAC Protocol Design4)
Optimizing or “tuning” a basic schemeHow many channels to allocate in a circuit-switched system?Effectiveness of collision avoidance schemes in a contention-based system?Efficiency of scheduling schemes in a reservation-based system?
Specifying system performanceHow many users?How much capacity per user?Physical layer requirements?
::: Referensi :::
•Stallings, W. 1998. High Speed Networks: TCP/IP and ATM Design Principles, Prentice-Hall.•McDysan, D. 2000. QoS and Traffic Management in IP and ATM Networks. McGraw-Hill, Corp. New Jersey.•Bloomers, J. 1996. Practical Planning for Network Growth. Prentice Hall, Inc. New Jersey.•R. Jain, The Art of Computer Systems Performance Analysis: Techniques for Experimental Design, Measurement, Simulation, and Modeling, John Wiley and Sons, 1991.•M. H. MacDougall, Simulating Computer Systems: Techniques and Tools, MIT Press, 1987.•D. W. Petr, Course Notes, The University of Kansas, 1999.
Referensi
(1)Leon, A. and Indra W. 2000. Communication Networks: Fundamental Concepts and Key Architectures. Int'l Ed. McGraw Hill Inc. Singapore. ISBN 0-07-022839-6.(2)Internet Software Consortium. Internet at http://www.isc.org(3)NGN. Seminar NGN di ITB & Jakarta(4)ZTE telecom, Next Generation Network, Huawei Technologies, ANJA 2003(5) _______, ‘Next Generation Network’, paper, Nusantara 2001, TELKOM(6)NEC Corp. , NGN Scenario for broadband services, presentation, 2003(7)_______, ‘Next Generation Network’, Web Forum Tutorial, International Engineering Consortium (IEC), www.iec.org.(8)_______, ‘Next Generation Network’, Web Forum Tutorial, International Engineering Consortium (IEC), www.iec.org.(9)_______, ‘Next Generation Network’, paper, iSwitch, www.UTstar.com.(10) KPSI. 2007. Laporan Program INHERENT dan IMHERE.(11) KPSI. 2006. Laporan Kegiatan Tahunan KPSI IPB.(12) KPSI. 2004 – 2006. Laporan Proyek Pengembangan Infrastruktur dan Layanan TIK IPB.(13) KPSI. 2004. Panduan Prosedur Standar (SOP) KPSI. IPB.(14) IPB. 2004. Press Release Pembangunan Jaringan Backbone Kampus Berbasiskan Serat Optik IPB.(15) KPSI. 2000. Panduan Singkat IPBNet.
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