TcL Scripting for Cisco IOS, Rough Cuts

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  • Copyright 2010
  • Dimensions: 7-3/8" x 9-1/8"
  • Pages: 320
  • Edition: 1st
  • Rough Cuts
  • ISBN-10: 1-58705-954-1
  • ISBN-13: 978-1-58705-954-4

This is the Rough Cut version of the printed book.

A guide to building and modifying Tcl scripts to automate network administration tasks

Streamline Cisco network administration and save time with Tcl scripting

Cisco networking professionals are under relentless pressure to accomplish more, faster, and with fewer resources. The best way to meet this challenge is to automate mundane or repetitive tasks wherever possible. In this book, three Cisco experts show you how to use Tcl scripting for Cisco IOS devices to do just that.

You’ll learn easy techniques for creating, using, and modifying Tcl scripts that run directly on Cisco network devices from the Cisco IOS command line. The authors first teach basic Tcl commands and concepts for capturing and manipulating data and for querying or controlling Cisco equipment. Building on these core skills, they show you how to write scripts that automate and streamline many common IOS configuration, monitoring, and problem-solving tasks.

The authors walk through the entire script development process, including planning and flowcharting what you want to accomplish, formatting your code, adding comments, and troubleshooting script errors. They also present many downloadable sample scripts, along with practical guidance for adapting them to your own environment.

Whatever your role in managing, monitoring, or securing Cisco IOS networks and equipment, this book will help you get the job done more rapidly and efficiently.

Ray Blair, CCIE No. 7050, is a Cisco vertical solutions architect specializing in large network designs. He has more than 20 years of experience in designing, implementing, and maintaining networks, and maintains three CCIE certifications.

Arvind Durai, CCIE No. 7016, Advanced Services Technical Leader for Cisco, specializes in supporting major Cisco enterprise customers in finance, manufacturing, e-commerce, government, and healthcare. He holds CCIEs in Routing and Switching, and in Security.

John Lautmann, Cisco Software Engineer, has developed and enhanced network management software for twelve years, and holds six patents. He has helped develop new Cisco IOS features ranging from data link switching to IOS Tcl Interpeter and digitally signed Tcl scripts.

  • Automate routine administration tasks you’ve always performed manually
  • Instantly collect and modify IOS router configurations and other data
  • Write Syslog scripts to document failures, monitor network health, collect statistics, and send alarm messages
  • Implement automated network performance measurement using IP SLA
  • Use the Embedded Event Manager’s event detectors, server, and policies to customize device operation
  • Trigger preplanned actions to correct problems as they arise
  • Simplify policy management using the Tcl script refresh feature
  • Protect Tcl script security with digital signatures and PKI
  • Understand how Tcl functions within the Cisco IOS environment
  • Master Tcl syntax and commands through hands-on practice
  • Learn best scripting practices through expert examples
  • Quickly modify this book’s examples for your own environment

This book is part of the Networking Technology Series from Cisco Press®, which offers networking professionals valu

Table of Contents

Introduction xiv

Chapter 1 The Origin of Tcl 1

    Tcl and Cisco IOS Software 3

        Embedded Event Manager and Tcl 4

        Restriction of Tcl in IOS 4

        Tcl with EEM Support in IOS 5

    Using Tcl Scripts in the Network 8

        Troubleshooting Problems 8

        Monitoring the Network 8

        Adding Intelligence to Cisco IOS Protocols 9

    Summary 9

    References 9

Chapter 2 Tcl Interpreter and Language Basics 11

    Simple Variables in Tcl 12

        Storing Variables 12

        Viewing Variables 13

        The append Command 13

        The incr Command 13

        Representation of Variables in Tcl 14

        Command Substitution 14

        Variable Substitution 15

        Lists 17

        lappend 18

        lindex 18

        linsert 18

        llength 19

        lsearch 19

        lreplace 20

        lrange 20

        lsort 20

    Procedures 21

        for Command 22

        foreach Command 23

        while Command 23

    Arrays 24

    if Command 26

    switch Command 27

    Files 28

    Summary 31

    References 31

Chapter 3 Tcl Functioning in Cisco IOS 33

    Understanding the Tcl Interpreter in Cisco IOS 33

        Using Cisco IOS Exec-Mode Parser in the Tcl Shell 34

        Entering an IOS Command into the Tcl Command Interpreter 35

    Using Tcl to Enter Commands 36

    Copying a Tcl Script to a Cisco IOS Device 38

        Fetching a Cisco IOS Tc