1. Characterizing the
Existing Network
Designing and Supporting Computer Networks – Chapter 3
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2. 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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3. 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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4. 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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5. 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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6. 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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7. 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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8. 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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9. 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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10. 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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11. 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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12. 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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13. 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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14. 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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15. Perform a Wireless Site Survey
 Preparation
 Site survey
 Security
 Safety guidelines
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16. Perform a Wireless Site Survey
 Identify possible sources of signal interference
 Identify physical infrastructure issues
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17. Perform a Wireless Site Survey
 Define customer requirements
 Identify coverage areas
 Determine preliminary access point locations
 Measure signal strength
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18. 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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19. Organize Collected Data into a New
Network Design
 Identify and record the overall goal of the proposed
network design
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20. Organize Collected Data into a New
Network Design
 Identify and record the scope of the proposed network
upgrade
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21. 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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22. 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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23. 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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24. © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 24