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CCNA 3 v3.0 Module 6 Switch Configuration

Cisco Networking Academy

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Objectives

• Starting the switch

• Configuring the switch

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Switches

• A switch is a Layer 2/Layer 3 network device that acts as the concentration point for the connection of workstations, servers, routers, hubs, and other switches.

• Switches are multi-port bridges.

• Switches are the current standard technology for Ethernet LANs that utilize a star topology.

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Switches

• Switches are dedicated, specialized computers, which contain a central processing unit (CPU), random access memory (RAM), and an operating system.

• A switch can be managed by connecting to the console port to view and make changes to the configuration.

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Physical Startup of Catalyst Switches

• Switches typically have no power switch to turn them on and off.

• They simply connect or disconnect from a power source.

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Fixed Configuration and Modular Switches

• Some switches are fixed configuration:

2900XL, 2950, 3500 and 3550

Fixed configuration switches have a set number of interfaces (FastE or GigE).

• Other switches are modular:

4000, 5000, 5500 and 6500

Modular switches have a chassis which can hold different modules for different functionality.

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Fixed Configuration and Modular Switches

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Switch LED Indicators

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Verifying Port LEDs During Switch POST

• Once the power cable is connected, the switch initiates a series of tests called the power-on self test (POST).

• The System LED indicates the success or failure of POST.

• The Port Status LEDs turn amber for about 30 seconds as the switch discovers the network topology and searches for loops.

–15 seconds “listening” and 15 seconds “learning”

• To allow the port to go directly to “forwarding” state, use the ‘spanning-tree portfast’ command at the interface.

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Connecting a Switch to a PC

Console is in the back of the switch

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Examining Help in the Switch CLI

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Show Commands in User EXEC Mode

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Verifying the Catalyst Switch Default Configuration

• show running-config

• show interface

• show vlan

• show flash

• show version

• dir flash:

• show vtp counters|domain

• show mac-address-table

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Configuring the Catalyst Switch

• To overwrite any existing configuration, follow these steps:

– Remove any existing VLAN information by deleting the VLAN database file, vlan.dat from the Flash memory directory.

– Make sure the switch is not connected to any other switches.

– Erase the backup configuration file startup-config.

– Reload the switch.

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Configuring the Catalyst Switch

Web Management Interface

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Managing the MAC Address Table

Switches learn the MAC addresses of PCs or workstations that are connected to their switch ports by examining the source address of frames that are received on that port.

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Configuring Static MAC Addresses

• Using static MAC address entries increases security …and administration.

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Configuring Port Security

Another option for increased security is to configure port security bylimiting the maximum number of MAC addresses allowed on that portto one and shutting down the port if another MAC address is learned.

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Executing Adds, Moves, and Changes

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Managing Switch Operation

• An administrator should document and maintain the operational configuration files for networking devices.

• The most recent running-configuration file should be backed up on a server or disk.

• The Cisco IOS Software should also be backed up to a local server. The Cisco IOS Software can then be reloaded to Flash memory if needed.

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Passwords

• For security and management purposes, passwords must be set on the console and vty lines.

• An enable password and an enable secret password must also be set.

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Firmware and IOS Images

• IOS and firmware images are periodically released with bugs fixed, new features introduced, and performance improved.

• If the network can be made more secure, or can operate more efficiently with a new version of the IOS, then the IOS should be upgraded