Table Of Contents

Getting Started

Before You Begin

Switch Configuration Steps

Using the Command Line Interface

Cisco IOS Command Modes

How to Find Cisco IOS Commands and Syntax

Getting Started

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This chapter describes how to configure the Catalyst 4840G SLB switch, lists the information you need before you begin, and describes Cisco IOS command modes. This chapter includes the following topics:

•Before You Begin

•Switch Configuration Steps

•Using the Command Line Interface

•Cisco IOS Command Modes

•How to Find Cisco IOS Commands and Syntax

Before You Begin

Before configuring the load-balancing switch, you should have the following information available:

•A map of your network topology

•The network protocols you are supporting

•The routing protocol you will use for each network protocol

•The IP addresses and the IP subnet masks for each network interface

•The IP addressing plan for each network protocol

•The IP addresses of your real servers

•The IP addresses of your virtual servers

•The IP addresses of your firewalls, if you are using them

Switch Configuration Steps

This list of steps suggests the order in which you should configure your Catalyst 4840G SLB switches in your network.

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Step 1 Set up the hardware as described in the chassis installation guide for your SLB switch.

Step 2 Configure the SLB processor. See "Configuring the Catalyst 4840G Processor."

Step 3 Configure the interfaces. See "Configuring Interfaces."

Step 4 Configure server load balancing. See "Server Load Balancing."

Step 5 Configure firewall load balancing. See "Firewall Load Balancing."

Step 6 Configure SLB redundancy. See "Configuring SLB Redundancy."

Step 7 Configure networking and routing protocols. See "Configuring Networking Protocols."

Step 8 Configure bridging. See "Configuring Bridging."

Step 9 Configure EtherChannel. See "Configuring EtherChannel."

Step 10 Perform optional system management and performance tasks.

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Using the Command Line Interface

You can configure the Catalyst 4840G SLB switch from the command-line interface (CLI) that runs on the switch console or terminal, or by remote access.

To use the CLI, your terminal must be connected to the switch through the console port or one of the TTY lines. The terminal has a basic default configuration that works for most terminal sessions.

Cisco IOS Command Modes

The Catalyst 4840G SLB switch runs on Cisco IOS software. The Cisco IOS user interface is divided into several different modes. The commands available to you depend on which mode you are currently in. To get a list of the commands available in a given mode, type a question mark (?) at the system prompt.

When you start a session on the Catalyst 4840G SLB switch, you begin in user mode, often called EXEC mode. Only a limited subset of the commands are available in EXEC mode. To have access to all commands, you must enter privileged EXEC mode. Normally, you must type in a password to access privileged EXEC mode. From privileged mode, you can enter an EXEC command or access global configuration mode. Most of the EXEC commands are one-time commands, such as show commands, which show the current configuration status, and clear commands, which clear counters or interfaces. The EXEC commands are not saved across reboots of the switch.

The configuration modes allow you to make changes to the running configuration. If you later save the configuration, these commands are stored across switch reboots. You must start at global configuration mode. From global configuration mode, you can enter interface configuration mode, subinterface configuration mode, and a variety of protocol-specific modes.

ROM monitor mode is a separate mode used when the switch cannot boot properly. For example, the switch might enter ROM monitor mode if it does not find a valid system image when it is booting, or if its configuration file is corrupted at startup.

Table 2-1 describes the most commonly used modes, how to enter the modes, and the resulting system prompts. The system prompt helps you identify which mode you are in and so you know which commands are available to you.

Table 2-1 Frequently Used Cisco IOS Command Modes

Mode	Description of Use	How to Access	Prompt
User EXEC	To connect to remote devices, change terminal settings on a temporary basis, perform basic tests, and display system information.	Log in.	SLB-Switch>
Privileged EXEC (Enable)	To set operating parameters. The privileged command set includes the commands in user EXEC mode as well as the configure command. Use this command to access the other command modes.	From the user EXEC mode, enter the enable command and the enable password.	SLB-Switch#
Global configuration	To configure features that affect the system as a whole.	From the privileged EXEC mode, enter the configure terminal command.	SLB-Switch(config)#
Interface configuration	To enable features for a particular interface. Interface commands enable or modify the operation of a Gigabit Ethernet or Fast Ethernet port.	From global configuration mode, enter the interface type location command. For example, enter interface fastethernet 1 or interface gigabitethernet 41.	SLB-Switch(config-if)#
Line configuration	To configure the console port or VTY line from the directly connected console or the virtual terminal used with Telnet.	From global configuration mode, enter the line console 0 command to configure the console port, or the line vty line-number command to configure a VTY line.	SLB-Switch(config-line)#

The Cisco IOS command interpreter, called the EXEC, interprets and executes the commands you enter. You can abbreviate commands and keywords by entering just enough characters to make the command unique from other commands. For example, you can abbreviate the show command to sh and the configure terminal command to config t.

When you type exit, the load-balancing switch backs out one level. In general, typing exit returns you to global configuration mode. To exit configuration mode completely and return to privileged EXEC mode, enter End.

How to Find Cisco IOS Commands and Syntax

In any command mode, you can get a list of available commands by entering a question mark (?).

SLB-Switch> ?

To obtain a list of commands that begin with a particular character sequence, type in those characters followed immediately by the question mark (?). Do not include a space. This form of help is called word help, because it completes a word for you.

SLB-Switch# co?

configure

To list keywords or arguments, enter a question mark in place of a keyword or argument. Include a space before the question mark. This form of help is called command syntax help, because it reminds you which keywords or arguments are applicable based on the command, keywords, and arguments you have already entered.

SLB-Switch# configure ?

	memory               Configure from NV memory

	network              Configure from a TFTP network host

	overwrite-network    Overwrite NV memory from TFTP network host

	terminal             Configure from the terminal                         

To redisplay a command you previously entered, press the up-arrow key. You can continue to press the up-arrow key to see more previously issued commands.

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Tips If you have trouble entering a command, check the system prompt, and enter the question mark (?) for a list of available commands. You might be in the wrong command mode or using incorrect syntax.

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You can enter End in any mode to immediately return to privileged EXEC (enable) mode, instead of entering exit, which returns you to the previous mode.