ITNE3006.pdf
Lesson_01 Lecture.pdf
ITNE3006 Session 1 1Copyright © 2018 VIT, All Rights Reserved
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ITNE3006
Design Network Infrastructure
ITNE3006 Session 1 2Copyright © 2018 VIT, All Rights Reserved
Copyright © XXXXXXXXXX, Victorian Institute of Technology.
The contents contained in this document may not be reproduced in any form or by any means, without the written permission of VIT,
other than for the purpose for which it has been supplied. VIT and its logo are trademarks of Victorian Institute of Technology.
Lesson 1
Network Design
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Overview
• Introduction to Network
• A Good Network Design
• Design Principles
• Network Designing Tasks
• Modular Network Design
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Introduction To Network
Network provide the ability for people or devices to communicate with each other.
Data Network: Network that allows computers to exchange data.
Eg. Two PCs connected through a cable.
Internetwork: A collection of individual networks that are connected
y networking devices and that function as a single large network.
E.g. Internet
The first networks were LANS: Multiple users in relatively
small geographical area to exchange files and messages and to
access shared resources.WANs were introduced to interconnect these
LANS so that geographically dispersed users could also share information.
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A Good Network Design
Design: The plan of creating something.
DESIGN→ Creativity & Skills+ Existing Structure and Use + Requirements.
A Good Network Design includes
• Understanding the requirements
• Understanding the existing structure
• Understanding how the features operate
• Understanding the operational constraints
• Understanding the alternative approaches
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Design Principles
PDIOO Network Life Cycle: Network Lifecycle to describe the multiple
phases through which a network passes.
P Plan
D Design
I Implement
O Operate
O Optimize
R Retirement
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Design Principles
• Plan Phase- The detailed network requirements are identified,
and the existing network is reviewed.
• Design Phase- The network is designed according to the initial
equirements and additional data gathered during analysis of the
existing network.
• Implement Phase- The network is built according to the
approved design.
• Operate Phase- The network is operational and is being
monitored. This phase is the ultimate test of the design.
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Design Principles - Continued
• Optimize phase- During this phase, issues are detected and
co
ected , either before problems arise or, if no problems are
found, after a failure has occu
ed. Redesign must be required if
so many problems exists.
• Retirement Phase- Although not part of the PDIOO acronym,
this phase is necessary when part of the network is outdated or is
no longer required.
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Design Principles
Network Designing should include the following tasks.
• Determine Requirements
• Analyze the existing network, if one exists
• Prepare the preliminary design
• Complete the final design development
• Deploy the network
• Monitor and Redesign if necessary
• Maintain Documentation
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Design Principles
Figure. Network Design is an Ongoing Process
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Network Designing Tasks
1. Determining Requirements
Many types of requirements must be considered, including the Technical
and Business issues.
Technical Requirements
• Applications that are to run on the network
• Internet connections required
• Addressing restrictions
• Support for IPv6
• Other protocols that are to run on the network
• Cabling Requirements
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• Redundancy Requirements
• Use of proprietary equipment protocols
• Existing equipment that must be supported
• Network services required (QoS, Wireless etc.)
• Integration of security
• Solutions required for voice traffic, content networking, storage
networking etc.
• Network Management
• Support for existing applications
• Bandwidth Availability
Network Designing Tasks 1
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Network Designing Tasks - 1
Business Requirements
• Budget
• Schedule
• People
• Legal
• History
• Policies
Extracting Requirements is a difficult task. At the end of the
project, you should easily be able to determine whether a
equirement has been met.
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Network Designing Task - 2
2. Analyzing the Existing Network
An existing network may restrict the network design in some manne
Because
• Existing cabling might not be optimal, but have to be kept for cost
easons
• VPN portion might not have to be changed
Network information can be obtained through
• Commands (e.g. show version in Cisco IOS)
• Protocol Analyzers
• Network Analyzers
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Network Designing Task - 3
3. Preparing the Preliminary Design
• Preliminary design involves considering all the network
equirements and constraints, and determining the viable
alternative solution.
• After alternative solutions have been developed, the optimal
solution must be chosen.
• A top down approach is recommended for the network design.
Top down approach: Requirement are considered first, with the
applications and network solutions that will run on the network
driving the design.
Bottom up approach: First select devices, features, cabling and so
on and then try to fit the applications onto this network.
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Network Designing Tasks - 4
4. Completing the Final Design Development
Developing final design involves
• Producing detailed drawings
• Configuration Specification Costing
• Addressing Plans
• Other required information for implementation.
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Network Designing Tasks - 5
5. Deploying the Network
The deployment plan should include
• Details of what is to be done
• Details of how is to be done
• Scheduling
• Contingency Plans
• Testing
• Any training for the personnel if required
• Negotiate any contracts
• Documentation
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Network Designing Tasks - 6
6. Monitoring And Redesigning
• Gather operational statistics
• Monitor for anomalies and problems
• Redesign if required for the entire portion of the network
• Monitoring and redesign occur at the OO phase of PDIOO
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Network Designing Tasks - 7
7. Maintaining Design Documentation
The design should be documented throughout the process.
Documentation should include
• All the agreed to requirements and constraints
• The state of existing network, if any
• Preliminary design options and
ief review of why final design
was chosen
• Final design details
• Results of any pilot or prototype testing
• Deplyment plans, schedules, and other implementation details
• Monitoring requirements
• Any other pertinent information
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Modular Network Design
A module is a component of a composite structure.
Modular Network Design involves creating modules that can then
put together to meet the requirements of the entire network.
Modular Network- Benefits
• It is easier to understand and design smaller, simpler modules
ather than an entire network.
• Easier to troubleshoot smaller elements compared to the entire
network
• The reuse of blocks saves design time and effort, as well as
implementation time and effort.
• The reuse of blocks allows the network to grow more easily,
providing network scalability.
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Modular Network Design
Modular Network- Benefits – Cont.
• It is easier to change modules rather than the entire network,
providing flexibility of design.
Examples of Modular Network Designs are
1. Hierarchical Network Design
2. Cisco Enterprise Composite Network Model.
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Hierarchical Network Design
The Hierarchical Network Design model separates the network into
three functions.
Access Layer: Provides user and workgroup access to the
esources of the network.
Distribution Layer: Implements the organizations policies and
provides connections between workgroups and between workgroups
and the core.
Core Layer: Provides high speed transport between distribution-
layer devices and to core resources.
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Hierarchical Network Design
Figure. Hierarchial Network Design Model as Mapped to a Simple Network
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Hierarchical Network Design - Distribution Laye
The distribution layer interfaces between the core and access
layers, and between access layer workgroups.
The distribution layer functions and characteristics include the
following:
• Implementing policies by filtering, and prioritizing and queuing
traffic.
• Routing between the access and core layers. If different routing
protocols are implemented at these other two layers, the
distribution layer is responsible for redistributing among the
outing protocols, and filtering if necessary.
• Performing route summarization. When routes are summarized,
outers have only summary routes in their routing tables, instead
of unnecessary detailed routes.
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Hierarchical Network Design - Distribution Laye
• Providing redundant connections, both to access devices and to
core devices.
• Aggregating multiple lower-speed access connections into higher-
speed core connections and converting between different media
types (for example, between Ethernet and Frame Relay
connections), if necessary.
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Hierarchical Network Design - Access Laye
The access layer is where users access the network.
• Users can be local or remote.
• Local users typically access the network through connections to a
hub or a switch.
• Switches operate at Layer 2, and each port on a switch is its own
collision domain, meaning that multiple conversations between
devices connected through the switch can be happening
simultaneously.
• Using a LAN switch rather than a hub has a performance
advantage.
• Remote users might access the network through the Internet,
using VPN connections, for example
• The access layer must also ensure that only users who are
authorized to access the network are admitted.
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Hierarchical Network Design - Core Laye
The core layer provides a high-speed backbone.
Functions and attributes of the core layer include the following:
• Providing high-speed, low-latency links and devices for quick
transport of data across the backbone.
• Providing a highly reliable and available backbone. This is
accomplished by implementing redundancy in both devices and
links so that