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NETWORK DESIGN
(REKABENTUK RANGKAIAN)
TJ3054
LECTURER: KHAIRUL NAJMY ABDUL RANI
ROOM NO: STM 201
OFFICE PHONE NO: 04-928 3724
E-MAIL ADDRESSES: [email protected]
OR
[email protected]
HOMEPAGE: http://www.angelfire.com/mo3/najmy
Overview of computer networking
• What is a computer networking?
– An interconnected collection of autonomous computer.
– 2 or more computers are said to be interconnected if they are
able to exchange (transmit/receive) information.
– Autonomous means that acting independently.
• What is a distributed system?
– The existence of multiple autonomous computers, which are
not visible to the user.
– The distinction between CN and a DS lies with the SW (NOS)
rather than with the HW
• Why does a computer networking necessary?
– For organizations: Resource/Info. sharing, Saving cost,
Communication medium (audio/video conferencing/net
meeting), high reliability, security, scalability etc.
– For society: Remote access, Person-to-Person communication
(e-mail/messenger/chat), audio/video conferencing etc.
Overview of computer networking
• Computer networking can be classified based on type of
transmission technology and scale.
• 2 types of transmission technology, which are
[1] Broadcast Network [2] Point-to-Point Network.
• Broadcast Network have a single communication
channel that is shared by all the network devices.
– Broadcasting: A packet is transmitted, received and processed
by each network machines/devices.
– Multicasting: A packet is transmitted, received and processed
by a subset of the network machines/devices (e.g. stmnet,
studnet etc.)
• Point-to-Point Network consist of many connections
between individual pairs of machines.
Overview of computer networking
• Computer networking scale:
– Local Area Network (LAN): Privately owned networks within a
single building or organization or campus of up to a few
kilometers in size. (10 m to 1 km inter-processor distance).
– Metropolitan Area Network (MAN): A bigger version of LAN
and normally used similar technology covering a group of
nearby corporate offices/ a city either private or public (up to
10 km inter-processor distance).
– Wide Area Network (WAN): Spans a large geographical area,
often a country or continent (100 km to 1000 km interprocessor distance).
• Wireless Networks: Apply antennas, telephone with
analog modem and Cellular Digital Packet Data (CDPD)
service. Emerging technology: Bluetooth, GSM and
GPRS.
• Internet: a collection of homogonous interconnected
networks.
Overview of computer networking
• Vital CN hardware devices includes host computer,
front-end processor (FEP), modulator/demodulator
(modem), and terminal.
• Host computer: “Center computer/processor” within a
large data communication system. It can be a
mainframe or a minicomputer or a microcomputer.
• FEP is a special purposed computer, which can be
programmed to control and process data in a network. It
can be either a non-programmable and hardwired
communication control unit OR a programmable device
operating as a communication input/output and
processor. FEP components are channel interface, SW,
and line interface unit. FEP purposes are offloading
certain processing/controlling data from host computer
to a programmed processor, comm. line control, error
control, multiplexing, converting protocol/code and etc.
Overview of computer networking
• Modem transforms digital electrical pulse (generated by
computer/terminal) to analog signal before being
transmitted via analog voice grade circuit and vice
versa.
• Terminal is a input/output HW located at the
communication circuit end points. It can be
microcomputer or workstation or video terminal or
teleprinter terminal or dumb/intelligent terminal and etc.
• Other necessary HW devices that make network
becomes faster, more reliable and more secure are
MUX, protocol converter, HW encryption devices,
intelligent controller, line adapter and etc.
• HW equipments that are commonly used in LAN are
server, repeater, bridge, router, gateway, and cabling.
Overview of computer networking
• Several issues have to be touched when discussing
network SW, which is highly structured.
• Protocol hierarchies
– Network is arranged on the layer basis. Every layer will give
services to its upper layer. Every layer communicate with its
peer layer (same level) at other computer. In this case, a
protocol (an agreement on how peer communication should be
made) is required.
• Interface and Services
– Entity: Active element in each layer.
– SAP: The point where service can be obtained.
• Types
– Connection-oriented: Establish, use and release.
– Connectionless: Each packet is routed independently.
• QoS
– Reliable (acknowledged) OR Unreliable (not acknowledged)
Overview of computer networking
•
•
•
2 reference models: Open Systems Interconnection
(OSI) and Transmission Control Protocol/Internet
Protocol (TCP/IP).
The OSI deals with connecting open systems (open for
comm. with other systems).
The OSI has 7 layers:
1. Physical: mechanical, electrical, functional,
procedural
2. Data link: error & flow control: intermediate node
3. Network: routing, switching, network addressing
4. Transport: error & flow control, packetizing: end-toend
5. Session: establish communication
6. Presentation: format, compression, encryption
7. Application: application protocols
Overview of computer networking
Aplikasi
Presentation
Format data
physical port
Flow control
Session
Transport
encription
compression
Network
Data Link
Physical
Aplikasi A di
Komputer X
Aplikasi B di
Komputer Y
YYYYYXXXa
YXYFungsiLapisan Aplikasi
Fungsi
(Application layer)
FungsiFungsi
Lapisan Aplikasi
Lapisan layer)
(Application
OSI
Lapisan
OSI
Lapisan
Lapisan
Persembahan
Fizikal
(Presentation
layer)
 Bertanggun
gjawab
terhadap
penghantar
Lapisan
Sesi
an bit-bit
(Session
layer)
data.
 Menakrifka
Lapisan nPengangkutan
spesifikasi
(Transport
layer)
mekanikal,
elektrikal,
fungsian
dan
Lapisan Rangkaian
prosedur
(Network layer)
penghantar
an bit-bit
data.
LapisanBiasanya
Pautan Data

(Data dilaksanak
Link layer)
an secara
perkakasan
 Contoh
Lapisan
Fizikal
piawaian
(Physical
pada layer)
lapisan ini
adalah RS232-C dan
RS-449.
Media Penghantaran
RANGKAIAN KOMUNIKASI
Lapisan
Lapisan
Persembahan
Fizikal
(Presentation
layer)
 Bertanggun
gjawab
terhadap
Lapisan
Sesi
penghantar
(Session
layer)
an bit-bit
data.
Menakrifka
 Lapisan
n
Pengangkutan
spesifikasi
(Transport
layer)
mekanikal,
elektrikal,
fungsian
Lapisan Rangkaian
dan
(Network layer)
prosedur
penghantar
an bit-bit
Lapisandata.
Pautan Data
(DataBiasanya
Link layer)

dilaksanak
an secara
perkakasan
Lapisan
Fizikal
Contoh

(Physical
layer)
piawaian
pada
lapisan ini
adalah RS232-C dan
RS-449.
Overview of computer networking
• The OSI principles:
– Each layer can be implemented independently
– Each layer communicates with its peer layer (same level)
– Each layer needs service provided by bottom layer esp.
related to primitive functions.
• In the real world:
– There is almost no OSI product.
– In LAN, the 2 most bottom layer used LAN standard.
– In WAN, the 3 most bottom layer used X.25, ATM and FR
Overview of computer networking
•
TCP/IP has 4 layers:
1. Network interface/physical communication: Connects
the network using some protocol so it can
send/receive IP packet over it.
2. Internet (IP): Permits hosts to injects packet into any
network and have them travel independently to the
destination. This layer defines an official packet
format and protocol known as Internet Protocol (IP).
3. Transport (TCP/UDP): Allows peer entities on the
source and destination hosts to do conversation.
Transmission Control Protocol (TCP) is a reliable
connection-oriented protocol that allows a byte
stream originating on one machine to be delivered
without error to any other machine in the Internet.
User Datagram Protocol (UDP) is an unreliable
connectionless protocol that do not want TCP
sequencing or flow control.
Overview of computer networking
4. Application: Contains all the higher level protocols,
such as virtual TELNET, FTP, SMTP, POP3, DNS,
HTTP and etc.
Application
Presentation
SNA
Application
Application
Session
Transport
TCP/UDP
NetBios
Network
IP
NetBuei
Data Link
Physical
Communication
Physical
Physical
network
IPX/
SPX
AppleTalk
Overview of computer networking
• Standard can affluence the current network design and
implementation, such as tackling problems related to
HW and SW.
• Standard are usually enacted/regulated by vendors, users
and ISPs OR NSPs.
• Standard are usually drafted by certain committee,
which some of the members are vendor representatives
• Standard can be either de jure or de facto.
• de jure: is being enacted by formal/official bodies, such
as IEEE, ISO, ANSI etc.
• de facto: is being established by informal organization,
such HW/SW manufacturers like Microsoft, IBM etc.
• ISO is being represented by 90 countries dealing with a
lot of standard subjects.
Intro. of system approach in network design
• Actually, there are a lot of approach types can be made
in designing a new network or in upgrading an existing
network.
• In this course, the system approach is being chosen to
design a network or to upgrade an existing network.
• The system approach can be used by network designer
in: [1] planning a new data communication network [2]
troubleshooting or upgrading the performance of a
current network [3] planning a public data network.
• In designing a network, all the affluence factors and
limitations/problems should be clarified and highlighted
their effects on the network performance.
• The key of success starting from a good and effective
planning particularly, based on fulfilling the system user
interface requirement
Intro. of system approach in network design
•
Currently, network designer usually emphasizes on
user application system. In this case, 2 types of
network user should be classified, which are
organization management (e.g.
manager/director/employer) and individual user (e.g.
employee/subordinate).
•
Manager needs a reliable network so that they believe
whatever messages that they receive.
•
User needs a consistent/stable network so that they
can keep maintaining/upgrading their productivities.
•
There are 13 basic steps used in network design.
1. Feasibility Study
 The main purpose is to improve the current network
or to build entirely a new network for
organization/public.
Intro. of system approach in network design
1.
Feasibility Study (Continued)
 The responsibility is to define clearly the problem
existed and make it as (a) written document. In the
document, highlight the problems, possible root
causes, possible counter measures (solutions) that can
be offered and the objective/benefits of building a
new network. Besides, state also the complete and
realistic costs for a newly designed network or
accurate costs/benefits comparison for an upgraded
network.
2. Prepare a Network Design Plan(s)
 The main purpose is to provide a framework(s) for
the network design plan. Ensure that the plan meets
the requirements. Identify also possible constraints.
Besides, enlist functions that newly
upgraded/designed network can perform.
Intro. of system approach in network design
3.
Understand the current/existing network
 Try to know fully attributes of existing network
system, such as operational functionality and HW
(CPU type, memory size and configurations), SW
(type applications and network drivers/NOS),
protocols and standards, and operational support
methods. Besides, enlist some proposed network
application for future use. If possible put written
ideas in terms of notes/DFD/flowchart.
4. Define the network requirement
 The purpose is to determine the what in the
development of a new network and to describe
attribute the network must contain. Conceptually,
identify inputs, such as user needs, organizational
needs, existing systems, regulations, and environment
politics in order to draw out the network requirements
and constraints. In details, review the org. long and
short term plan.
Intro. of system approach in network design

Also, simulate the circuit capacity, reliability and
processing time (response time/queuing theories). If
possible, highlight future requirement(s) that may be
uncovered for now.
5. Define the geography scope
 The purpose is to identify the physical location that
must be interconnected by the newly designed or
upgraded network. There are 4 basic levels in
mapping the network, which are International,
Country, State/City, and Local Area/Facility.
6. Analyze the message
 The purpose is to identify msg. char., no. of msg. and
how to estimate volume of message. This step can be
done simultaneously with step no. 5 above. The
output is a list of msg. With no. of char. per msg.,
network link traffic table.
Intro. of system approach in network design
7.
Calculate the network traffic and circuit loading
 The purpose is to calculate the circuit capacity that is
needed for traffic based on no. of char. per msg.&
no. of msg. delivered per given period of time.
Therefore, needs to calculate the response time /
turnaround time. RIT = MIT + APT + MOT.
Besides, it is possible to show the circuit capacity req.
for each link. The output is the documented of traffic
analysis (msg. & total of char. per day).
8. Identify network control and security
 The purpose is to control and protect info. from
various threats, such as errors & omissions, msg.
Loss/damage, disasters, poor error handling,
viruses/worms, unreliability etc. Use ctrl spreadsheet
to identify, prepare document and re-evaluate all the
ctrl point within a network. The output are ctrl
spreadsheet, list of threats def. & list of ctrl methods
Intro. of system approach in network design
9.
Design network configuration
 The purpose is to configure the network based on
network goals/objectives.The ckt. config. is done btw.
The user and host computer. The result depends on
node/terminal and SW/HW changing. The output is
the network config. maps/layouts and list of network
goals.
10. Consider the SW selection
 The purpose is to overcome the limitation resulted by
terminal usage and diff. types of SW used thru the
using of protocol converter/router/gateway. The
output is the details of network config. Either it is
PTP or Multiplexed or Multidropped or Packet
switched or combinations of above. Besides, there
should be a description of protocol selected as well as
WAN/LAN SW documentation.
Intro. of system approach in network design
11. Consider the HW selection
 The purpose is to get all the HW required. The HW of
network can be categorized as transmission media
and internetworking devices.The output is the layout
and the config. (multidrop/multiplex, etc.) showing
all the linked nodes.
12. Calculate the cost required
 The purpose is to estimate the cost of
building/upgrading a network and to review the
complexity of costing on the chosen network
configuration. A lot of techniques can be used to
estimate the cost, such as network cost analyzer,
cost/benefit analysis, voice grade leased circuit cost,
dial-up circuit cost, wideband analog circuit cost,
digital circuit cost, T-carrier circuit cost, pkt sw. cost,
HW cost, and further design cost.
Intro. of system approach in network design
12. Calculate the cost required
 The network cost generally can be classified into two
groups, which are direct cost and indirect cost. Direct
cost includes processor/server, comm. devices,
common carrier line tariffs, SW/NOS, spare part cost,
and maintenance cost. Indirect cost will be personnel
training and disruption of normal activities. The
output is a report of network expenditure generated
by network cost analyzer.
13. Implement the new network
 There will two subtasks, which are selling the
proposed network to mgmt. or to client/user and
implementing the network. Selling the network can
be done orally to top mgmt. There are 4P’s
techniques in implementing the network that are
Pilot, Phased, Parallel, and Plunge.