Configuring the Switch

1
Configuring the Switch

• There are two types of cable connections used to
  manage the switch. The first type is through the
  console port. The second type is via the Ethernet
  port.
• The console port is used to initially configure
  the switch, and the port itself normally does not
  require configuration. In order to access the
  switch via the Ethernet port, the switch must be
  assigned an IP address.

2
Configuring the Switch

• When connecting the switch's Ethernet ports to
  Ethernet-compatible servers, routers, or
  workstations, use a straight-through Category 5
  cable. When connecting the switch to another
  switch, you must use a crossover cable.

3
Configuring the Switch

• To connect a management terminal to the Cisco
  1900/2800 or 2900 XL Switch through the serial
  console, use the RJ-45-to-RJ-45 rollover cable
  supplied with the switch. Perform the following
  steps to cable the two devices
• Step 1 Connect one end of the supplied rollover
  cable to the console port.

4
Configuring the Switch

• Step 2 Attach one of the following supplied
  adapters to a management station or modem
• RJ-45-to-DB-9 female data terminal equipment
  (DTE) adapter (labeled Terminal) to connect a PC.

5
Configuring the Switch

• RJ-45-to-DB-25 female DTE adapter (labeled
  Terminal) to connect a UNIX workstation.
• RJ-45-to-DB-25 male data communications equipment
  (DCE) adapter (labeled Modem) to connect a modem.
• Step 3 Connect the other end of the supplied
  rollover cable to the adapter.
• Step 4 From your management station, start the
  terminal emulation program.

6
Configuring the Switch

• When connecting to a Catalyst OS "set command"
  based switch (such as the Catalyst 4000 and
  6000), you are presented with a password prompt
  at the initial login. The default password for a
  Catalyst 4000 is pressing the ENTER key. Assuming
  you enter the correct password, you enter the
  switch's NORMAL mode.

7
Configuring the Switch

• Normal mode equates to a router's User EXEC mode,
  allowing you to view most switch parameters, but
  not permitting any configuration changes.\
• To make changes, you must enter PRIVILEGED mode.
  The privileged mode functionally equates to the
  router PRIVILEGED EXEC mode.

8
Configuring the Switch

• In the privileged mode, you can view
  configuration files like you can with a router
  however, in the switch privileged mode you can
  make configuration changes, unlike a router where
  you have to enter global configuration mode.
• You enter the switch privileged mode with the
  enable command.

9
Configuring the Switch (Clearing the
Configuration)

• A foolproof way of ensuring that a new
  configuration completely overwrites an existing
  configuration is to enter the clear config all
  command for set command switches like the 4000
  series.
• This CLI command returns the switch Supervisor
  module to its default configuration where all
  ports belong to virtual LAN (VLAN) 1, there is no
  Virtual Trunking Protocol (VTP) domain and all
  Spanning-Tree parameters go back to their default
  values.

10
Configuring the Switch

• You can clear the configuration with any of the
  access methods, but if you do so while telnetting
  to the Catalyst Switch, you lose your connection
  because the switch no longer has an IP address.
• On a 2900 switch, the erase startup-config
  command erases the configuration that is stored
  in NVRAM.

11
Configuring the Switch

• On a 2900 switch, this does not erase the VLAN
  information. In order to erase the VLAN
  information, use the del flashvlan.dat command.
• To configure the switch, you must enter
  configuration mode by using the configure
  command. This command puts the switch in global
  configuration mode, where you are able to
  configure the switch.

12
Configuring the Switch

• Unlike set command-based switches, the Cisco IOS
  command-based switch does not immediately store
  commands in NVRAM, and does require you to
  perform a copy run start like a router.

13
Setting the Password

• To set passwords on a Cisco IOS software-based
  switch, enter either one or both of the following
  commands in global configuration mode
• Switch(config)enable password passwordSwitch(con
  fig)enable secret password.

14
Setting the Password

• Where password is a combination of four to eight
  alphanumeric characters. The difference between
  the two is that the enable secret command
  encrypts the password, whereas the enable
  password command displays the password in
  cleartext.

15
Setting the Hostname

• To set the host or system name on a Cisco IOS
  software-based switch such as the Cisco 2900 XL,
  enter the following command in global
  configuration mode
• Switch(config)hostname name.
• Where name can be from 1 to 255 alphanumeric
  characters.

16
Configuring the Switch for Remote Access

• Before you can Telnet to, ping, or globally
  manage the switch, you need to associate that
  switch with an IP address and the management
  VLAN. Although LAN switches are essentially Layer
  2 devices, these switches do maintain an IP stack
  for administrative purposes.

17
Configuring the Switch for Remote Access

• Assigning an IP address to the switch associates
  that switch with the management VLAN, provided
  the subnet portion of the switch IP address
  matches the subnet number of the management VLAN.

18
Configuring the Switch for Remote Access

• To assign an IP address on a Cisco IOS
  software-based switch, follow these steps
• Enter global configuration mode on the switch.
• Go to interface VLAN 1 by issuing the command
  Switch(config)interface vlan 1.
• Enter the switch IP address with the command
  Switch(config-if)ip address address mask.
• If you are accessing your switch via a router,
  you must configure a default gateway on the
  switch. This can be done in global configuration
  mode with the command Switch(config)ip
  default-gateway address.

19
Configuring the Switch for Remote Access

• The show ip interface command displays the IP
  address and the subnet mask for the device.
• The management interface resides in VLAN1, which
  is the default management VLAN, and has a subnet
  mask of 255.255.255.0.
• To remove the IP address and subnet mask, enter
  the no ip address command on the vlan interface.

20
Identifying Unique Ports

• You can add a description to an interface or port
  to help you remember specific information about
  that interface, such as what access or
  distribution-layer device the interface services.
  
• This command is very useful in an environment
  where a switch has numerous connections and the
  administrator needs to check a link to a specific
  location.

21
Identifying Unique Ports

• To add a unique comment to an interface on a
  Cisco IOS Software-based switch, enter the
  following command in interface configuration
  mode.
• Switch(config-if) description description
  string.
• If you want to enter a description with spaces
  between characters, you must enclose the string
  in quotation marks. For example
  Switch(config-if)description "Port to fourth
  floor switch."

22
Identifying Unique Ports

• To clear a description, enter the no description
  command on the interface in interface
  configuration mode.
• On a Cisco IOS software-based switch, the speed
  of the ports are set using the speed
  10100auto command from the interface mode.

23
Defining Line Mode on a Switch

• Full-duplex is the simultaneous action of
  transmitting and receiving data by two devices.
  This operation is achievable only if the devices
  on each end support full-duplex.
• Full-duplex links not only double potential
  throughput, but also eliminate collisions and the
  need for each station to wait until the other
  station finishes transmitting.

24
Full Duplex

• Full-duplex links are particularly useful for
  server-to-server, server-to-switch, and
  switch-to-switch connections.
• To set the duplex mode of an interface on a Cisco
  IOS software-based switch, enter the following
  command in interface configuration mode
• Switch(config-if)duplex auto full half.

25
Full Duplex

• Note Use the auto argument only for fixed Fast
  Ethernet TX ports. In auto-negotiation mode, the
  switch attempts to negotiate full-duplex
  connectivity with the connecting device. If
  negotiation is successful, the port operates in
  full-duplex mode. If the connecting device is
  unable to operate in full duplex, the port
  operates in half duplex. This process is repeated
  whenever there is a change in link status.

26
Full Duplex

• To return the duplex parameter to the default
  setting, enter the no duplex command in the
  interface configuration mode.