Network Design
A Step by Step Process
Design with Change in Mind
• Building the network is just the beginning
• Growing the network for larger numbers of
users
• Growing the network for more services
• Growing the network to include emerging
technologies
• It never stops
• Design for this from the very beginning
A Design Process
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Identify the uses of the network
List what happens on what computers
Client/server or P2P?
Diagram the network
Review your plans
Write a specification
Build the network
Identify the Uses of the Network
• Organisational purpose
– Network is not about technology
– Network is to serve a purpose
• Information collecting
– Management: core business
– Users: on-the-ground issues
– Collect, collate, and bring back for review
• Quantifying the Network
– # of users, # of machines
– Machines per user? Users per machine?
– Examples: Pick’n’Pay, UWC, software devel company
What Happens Where?
• Match applications/tasks to specific computers
• Rightsize: choose the capabilities of the machines
to match the use requirements
• Multiuser computers
– Servers: File, application, database, email, web
– Thin-client server
• Single-user computers
– Average user, power user
– Application suite
Centralisation
• Client/server vs. Peer-to-Peer
• Candidates for centralisation
– File services: uniform location
– Security: access and permissions
– Backup: uniform location
• Configuration Management
– Ensuring all machines have the same software and
hardware
– Why? Easier to fix problems if everything is (supposed
to be) configured the same
• Network Management Software
The Network Diagram
• Logical network diagram
– Start with the user
– Applications and resources
– Pay attention to sharing and security
• Physical network diagram
– Machines
– Network devices
– Physical connectivity
• Combined diagrams
– Diagram physical connectivity
– Show logical use with descriptive labels
Diagramming Best Practise
• Choose appropriate icons/images
• Label the icons clearly
• List the additional details in small text close to the icons, e.g. machine
name, IP address, etc.
• Use conventional methods to depict connectivity, e.g. Token Ring vs
Ethernet
• Use colour and styles to denote different types of connectivity
relationships, similar attributes, e.g. OS type, application, etc.
• Keep the overall layout simple and within page boundaries
• Use space to lay out the contents clearly – keep objects distinct with
space
• Resize objects to make best use of space and try to keep size of objects
relative to reality
• If using several different colours and/or line types, provide a legend in
an isolated corner
• Clearly identify the author(s) and target audience for the diagram
Write out Specification
• Write out a document with everything so far
• Why write a document?
– It’s not real until it’s on paper
– Defines the scope of the project (to protect you)
– Tangible item for reference
• Keep it short and clear
• Pass around the document for review
• Hold a review meeting and revise accordingly
Choose Hardware
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Workstation and server computers
Network interface cards
Network devices
Wiring
Application software
Management software
Choose a Vendor
• Best to get all the equipment from a single vendor
to avoid “finger pointing”
• Collect bids from multiple vendors
– Detailed description of solution
– Detailed quote
– Rollout plan
• What to look for in a vendor
– How frequent they meet with you? How well do the
meetings go?
– Do they listen to your needs or push their product?
– Can they provide references?
– Meet with the techies as well as the salespeople
Build the Network
• Decide how much of the actual building
your vendor is going to do
• If the network is very large and complex, or
if you are adding services/technologies to
an existing network, rather build a staging
environment first
• Be sure to pick a time (like a vacation)
when no one will be around