Characterizing the
Existing Network
Designing and Supporting Computer Networks – Chapter 3
Version 4.0 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 1

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
© 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 2

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
© 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 3

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
© 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 4

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
© 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 5

Diagram a Physical Network and
Document the Existing Network
 Create a modular block diagram
 Simplify the network to show major functions
© 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 6

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
© 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 7

Use CCO to Determine the Appropriate IOS
Version to Support Network Requirements
Cisco CCO features and navigation:
 Documentation
 Tools
 Downloads
 Communities and training
 News
© 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 8

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
© 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 9

Use CCO to Determine the Appropriate IOS
Version to Support Network Requirements
 Select the correct IOS image using the CCO IOS
Feature Navigator
© 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 10

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
© 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 11

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
© 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 12

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
© 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 13

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
© 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 14

Perform a Wireless Site Survey
 Preparation
 Site survey
 Security
 Safety guidelines
© 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 15

Perform a Wireless Site Survey
 Identify possible sources of signal interference
 Identify physical infrastructure issues
© 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 16

Perform a Wireless Site Survey
 Define customer requirements
 Identify coverage areas
 Determine preliminary access point locations
 Measure signal strength
© 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 17

Organize Collected Data into a New
Network Design
Design requirements document:
 Overall project goal
 Project scope
 Network requirements
 Current state of the network
© 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 18

Organize Collected Data into a New
Network Design
 Identify and record the overall goal of the proposed
network design
© 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 19

Organize Collected Data into a New
Network Design
 Identify and record the scope of the proposed network
upgrade
© 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 20

Organize Collected Data into a New
Network Design
 Identify and record the business goals and technical
requirements of the proposed network design
© 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 21

Organize Collected Data into a New
Network Design
 Characterize the existing network in relation to the
identified business goals and technical requirements
© 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 22

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.
© 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 23

© 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 24