This document discusses characterizing an existing network in preparation for an upgrade. It outlines objectives like documenting the network, using Cisco resources to determine appropriate software and hardware, performing a wireless survey, and organizing collected data. The goals are to identify strengths and weaknesses, ensure accurate inventory information, understand network flows, and define requirements for a new design that overcomes existing limitations. Key steps involve diagramming physical and logical views, using Cisco tools to choose IOS versions and modules, measuring wireless signals, and specifying an overall upgrade aim based on current business and technical needs.

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Characterizing the
Existing Network
Designing and Supporting Computer Networks – Chapter 3

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Objectives
 Diagram and document an existing network to identify
strengths and weaknesses in the design.
 Use CCO to determine the appropriate IOS version to
support network requirements and download and
install the appropriate IOS
 Use CCO to determine the appropriate hardware
features and install the upgrades using safe practices
and procedures
 Perform a wireless site survey
 Organize collected data into a new network design

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Diagram a Physical Network and Document the
Existing Network
Network documentation:
 Logical and physical diagrams
 Floor plans
 Inventory lists for equipment and applications
 Current network configuration files

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Diagram a Physical Network and Document the
Existing Network
 Log in to network devices
 Use Cisco IOS software commands to gain information
on routers and switches

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Diagram a Physical Network and
Document the Existing Network
 Create a logical network diagram showing existing
addressing, routing, and network segmentation
 Illustrate how information flows through the network

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Diagram a Physical Network and
Document the Existing Network
 Create a modular block diagram
 Simplify the network to show major functions

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Diagram a Physical Network and
Document the Existing Network
 Identify and document the strengths and weaknesses
of the existing network
 Focus on finding ways to overcome weaknesses

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Use CCO to Determine the Appropriate IOS
Version to Support Network Requirements
Cisco CCO features and navigation:
 Documentation
 Tools
 Downloads
 Communities and training
 News

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Use CCO to Determine the Appropriate IOS
Version to Support Network Requirements
 Use the show version command
 Verify that the inventory list is correct
 Obtain missing information

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Use CCO to Determine the Appropriate IOS
Version to Support Network Requirements
 Select the correct IOS image using the CCO IOS
Feature Navigator

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Use CCO to Determine the Appropriate IOS
Version to Support Network Requirements
 Download the correct IOS
 Store new IOS image on TFTP server
 Transfer the file to the Cisco router or switch

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Use CCO to Determine the Appropriate IOS
Version to Support Network Requirements
Three stages of the router bootup process:
 Perform the POST and load the bootstrap program
 Locate and load the IOS software
 Locate and execute the startup configuration, or enter
setup mode

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Use CCO to Determine the Appropriate
Hardware Features and Install the Upgrades
 Use datasheets to see what modules and interfaces are
available
 Determine the technologies and media a given device
will support

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Use CCO to Determine the Appropriate
Hardware Features and Install the Upgrades
Installing a new hardware option on a Cisco router or
switch:
 Turn off power
 Remove blank faceplace
 Install option module
 Turn on power and check the new configuration

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Perform a Wireless Site Survey
 Preparation
 Site survey
 Security
 Safety guidelines

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Perform a Wireless Site Survey
 Identify possible sources of signal interference
 Identify physical infrastructure issues

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Perform a Wireless Site Survey
 Define customer requirements
 Identify coverage areas
 Determine preliminary access point locations
 Measure signal strength

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Organize Collected Data into a New
Network Design
Design requirements document:
 Overall project goal
 Project scope
 Network requirements
 Current state of the network

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Organize Collected Data into a New
Network Design
 Identify and record the overall goal of the proposed
network design

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Organize Collected Data into a New
Network Design
 Identify and record the scope of the proposed network
upgrade

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Organize Collected Data into a New
Network Design
 Identify and record the business goals and technical
requirements of the proposed network design

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Organize Collected Data into a New
Network Design
 Characterize the existing network in relation to the
identified business goals and technical requirements

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Summary
 Ensure that network documentation is accurate and
complete before designing an upgrade
 Gather information using tools like Cisco Network
Assistant
 Organize the current network into a modular block
diagram to identify where the network needs to be
improved.
 The Cisco CCO site provides valuable tools and
documentation for the design process.
 Before producing a wireless network design, it is
usually necessary to do a wireless site survey.

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