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Installing and Operating Cisco LAN Switches


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CLI
The __ is a text-based interface in which the user, typically a network engineer, enters a text command and presses Enter.
Enter
Pressing __ on text command sends it to the switch, which tells the device to do something.
messages, results
The switch does what the command says, and in some cases, the switch replies with some __ stating the __ of the command.
Catalyst
Cisco __ switches also support other methods to both monitor and configure a switch.
web interface
For example, a switch can provide a __, so that an engineer can open a web browser to connect to a web server running in the switch.
2960
Cisco positions the __ series (family) of switches as full-featured, low-cost wiring closet switches for enterprises.
interfaces, ports
Cisco refers to a switch’s physical connectors as either __ or __.
x/y
Each interface on switches has a number in the style __, where they are two different numbers.
0/1 0/2
On a 2960 switch, the numbering of 10/100 interfaces starts at __, the second is __, and so on.
GigabitEthernet 1/1
The first 10/100/1000 interface on a 2960 would be “interface __.”
LEDs
The switch hardware does include several __ that provide some status and troubleshooting information, both during the time right after the switch has been powered on and during ongoing operations.
interface
Most Cisco Catalyst switches have some LEDs, including an LED for each physical Ethernet __.
SYST (system)
Implies the overall system status.
RPS (Redundant Power Supply)
Suggests the status of the extra (redundant) power supply.
STAT (Status)
If on (green), implies that each port LED implies that port’s status.
DUPLX (duplex)
If on (green), each port LED implies that port’s duplex (on/green is full; off means half).
SPEED
If on (green), each port LED implies the speed of that port, as follows: off means 10 Mbps, solid green means 100 Mbps, and flashing green means 1 Gbps.
MODE
A button that cycles the meaning of the LEDs through three states (STAT, DUPLX, SPEED).
Port
LED that has different meanings, depending on the port mode as toggled using the mode button.
Off
If SYST LED is __, switch is not powered on.
On (green)
If SYST LED is __,the switch is powered on and operational (Cisco IOS has been loaded).
On (amber)
If SYST LED is __, the system has power, but is not functioning properly.
above, below
The port LEDs—the LEDs sitting __ or __ each Ethernet port—mean something different depending on which of three port LED modes is currently used on the switch.
Off
If STAT LED is __, the link is currently not working (including if shut down).
Solid green
If STAT LED is __, the link is working, but there’s no current traffic.
Flashing green
If STAT LED is __, The link is working, and traffic is currently passing over the interface.
Flashing amber
If STAT LED is __, the port is blocked by spanning tree.
unlit, solid green, flashing green
in SPEED port LED mode, the port LEDs imply the operating speed of the interface, with an __ LED meaning 10 Mbps, a __ light meaning 100 Mbps, and __ meaning 1000 Mbps (1 Gbps).
Internetwork Operating System
Like any other piece of computer hardware, Cisco switches need some kind of operating system software. Cisco calls this OS the __.
IOS CLI
The Cisco __ allows the user to use a terminal emulation program, which accepts text entered by the user.
terminal emulator
When the user presses Enter in IOS CLI, the terminal emulator sends that text to the switch. The switch processes the text as if it is a command, does what the command says, and sends text back to the __.
console, Telnet, Secure Shell
The switch CLI can be accessed through three popular methods—the __, __, and __.
Telnet, SSH
Two of these methods (__ and __) use the IP network in which the switch resides to reach the switch.
console
The __ is a physical port built specifically to allow access to the CLI.
software, user’s device
Telnet and SSH require __ on the __, but they rely on the existing TCP/IP network to transmit data.
console port on the switch, serial port on the PC, cable
The physical console connection, uses three main components: the physical __, a physical __, and a __ that works with the console and serial ports.
nine, DB-9
The PC serial port typically has a D-shell connector (roughly rectangular) with __ pins (often called a __).
RJ-45–to–DB-9
You can use either a purpose-built console cable or make your own console cable using UTP cables and a standard __ converter plug.
rollover cable
For the UTP cabling in console connection, the cable uses __ pinouts, rather than any of the standard Ethernet cabling pinouts.
USB ports
PCs have migrated away from using serial ports to instead use __ for serial communications. Cisco has also begun building newer routers and switches with __ for console access as well.
software driver
When using the USB options in console connections, you typically also need to install a __ so that your PC’s OS knows that the device on the other end of the USB connection is the console of a Cisco device.
terminal emulator software package
After the PC is physically connected to the console port, a __ must be installed and configured on the PC.
text
The terminal emulator software on Cisco products treats all data as __.
console connection
The terminal emulator software accepts the text typed by the user and sends it over the __ to the switch.
configured, match
The emulator must be __ to use the PC’s serial port to __ the settings on the switch’s console port settings.
9600, No hardware flow control
The default console port settings on a switch are as follows: __ bits/second, __.
8-bit ASCII, No parity bits, 1 stop bit
The default console port settings on a switch are as follows: __, __, __.
8N1
The last three parameters of console port settings on a switch are referred to collectively as “__”
IP network
Telnet uses an __ to send and receive the data, rather than a specialized cable and physical port on the device.
Telnet client, Telnet server
The Telnet application protocols call the terminal emulator a __ and the device that listens for commands and replies to them a __.
Telnet, SSH
Most switch terminal emulator software packages today include both __ and __ client functions.
up, IP packets
The network between the PC and switch needs to be __ and working so that the PC and switch can exchange __.
Secure Shell
While Telnet works well, many network engineers instead use __ to overcome a serious security problem with Telnet.
clear-text
Telnet sends all data (including any username and password for login to the switch) as __ data.
encrypts
SSH __ the contents of all messages, including the passwords, avoiding the possibility of someone capturing packets in the network and stealing the password to network devices.
enable password security
When you enable Telnet and/or SSH access, you need to __ so that only authorized people have access to the CLI.
console line 0
Cisco switches refer to the console as a console line—specifically, __.
16, vty, 0 15
Switches support __ concurrent Telnet sessions, referenced as virtual terminal (__) lines __ through __.
line vty 0 15
The __ configuration command tells the switch that the commands that follow apply to all 16 possible concurrent virtual terminal connections to the switch, which includes Telnet as well as SSH access.
public key cryptography
SSH uses __ to exchange a shared session key, which in turn is used for encryption.
password, username
SSH requires slightly better login security, requiring at least a __ and a __.
user EXEC mode
All three CLI access methods covered so far (console, Telnet, and SSH) place the user in an area of the CLI called __.
user mode
User EXEC mode, sometimes also called __, allows the user to look around but not break anything.
executes
The “EXEC mode” part of the name refers to the fact that in this mode, when you enter a command, the switch __ the command and then displays messages that describe the command’s results.
enable mode, privileged mode
Cisco IOS supports a more powerful EXEC mode called __ (also known as __).
enable
Enable mode gets its name from the __ command, which moves the user from user mode to enable mode.
privileged mode
The other name for the enable mode, __, refers to the fact that powerful commands can be executed there.
reload
You can use the __ command, which tells the switch to reinitialize or reboot Cisco IOS, only from enable mode.
> #
If the command prompt lists the host name followed by a __, the user is in user mode; if it is the host name followed by the __, the user is in enable mode.
user mode, enable mode
IOS rejects the reload command when used in __ and accepts the command when the user is in __.
EXEC
The commands that can be used in either user mode or enable mode are called __ commands.
configuration
The switch will work without any __, just plug in the power and Ethernet cables, and it works.
Command Reference
If you printed the Cisco IOS __ documents, you would end up with a stack of paper several feet tall. No one should expect to memorize all the commands—and no one does.
?
Help for all commands available in this mode.
help
Text describing how to get help. No actual command help is given.
Command ?
Text help describing all the first parameter options for the command.
com?
A list of commands that start with com.
command parm?
This style of help lists all parameters beginning with the parameter typed so far. (Notice that there is no space between parm and the ?.)
command parm<Tab>
If you press the Tab key midword, the CLI either spells the rest of this parameter at the command line or does nothing. If the CLI does nothing, it means that this string of characters represents more than one possible next parameter.
command parm1 ?
If a space is inserted before the question mark, the CLI lists all the next parameters and gives a brief explanation of each.
?
When you enter the __, the Cisco IOS CLI reacts immediately; that is, you don’t need to press the Enter key or any other keys.
redisplays
The device running Cisco IOS also __ what you entered before the ? to save you some keystrokes.
user mode, enable mode
when ? is entered in user mode, the commands allowed in __ are displayed, but commands available only in __ are not displayed.
ten
Cisco IOS stores the commands that you enter in a history buffer, storing __ commands by default.
backward, forward
The CLI allows you to move __ and __ in the historical list of commands and then edit the command before reissuing it.
Up arrow or Ctrl+P
This displays the most recently used command. If you press it again, the next most recent command appears, until the history buffer is exhausted. (The P stands for previous.)
Down arrow or Ctrl+N
If you have gone too far back into the history buffer, these keys take you forward to the more recently entered commands. (The N stands for next.)
Left arrow or Ctrl+B
This moves the cursor backward in the currently displayed command without deleting characters. (The B stands for back.)
Right arrow or Ctrl+F
This moves the cursor forward in the currently displayed command without deleting characters. (The F stands for forward.)
Backspace
This moves the cursor backward in the currently displayed command, deleting characters.
Ctrl+A
This moves the cursor directly to the first character of the currently displayed command.
Ctrl+E
This moves the cursor directly to the end of the currently displayed command.
Ctrl+R
This redisplays the command line with all characters. It’s useful when messages clutter the screen.
Ctrl+D
This deletes a single character.
Ctrl+Shift+6
Interrupts the current command.
show
By far, the single most popular Cisco IOS command is the __ command.
show
The __ command has a large variety of options, and with those options, you can find the status of almost every feature of Cisco IOS.
show
The __ command lists the currently known facts about the switch’s operational status.
find the current status
The only work the switch does in react-ion to show commands is to __ and list the information in messages sent to the user.
debug
However, instead of just listing messages about the current status, the __ command asks the switch to continue monitoring different processes in the switch.
show, debug
The effects of the __ and __ commands can be compared to a photograph and a movie.
show, debug
A __ command shows what’s true at a single point in time, and it takes less effort and the __ command requires more CPU cycles, but it lets you watch what is happening in a switch while it is happening.
log messages
IOS reacts to debug commands by creating __ related to that debug command’s options.
terminal monitor
Any user logged in can choose to view the log messages, just by using the __ command from enable mode.
short-lived event, ongoing task
IOS also treats the show command as a very __ and the debug command as an __.
no debug spanning-tree
If the debug spanning-tree command had been issued earlier, issue the __ command to disable that same debug.
no debug all, undebug all
The __ and __ commands disable all currently enabled debugs on a switch.
show process
You might want to check the current switch CPU utilization with the __ command before issuing any debug command.
no debug all
To be more careful, before enabling an unfamiliar debug command option, issue a __ command and then issue the debug that you want to use.
nondisruptive, superset
User mode lets you issue __ commands and displays some information. Privileged mode supports a __ of commands compared to user mode, including commands that might harm the switch.
configuration commands
Configuration mode accepts __ that tell the switch the details of what to do and how to do it.
active configuration file
Commands entered in configuration mode update the __.
subcommand
Configuration mode itself contains a multitude of __ modes.
Context-setting
__ commands move you from one configuration subcommand mode, or context, to another.
interface
The __ command is one of the most commonly used context-setting configuration commands.
configure terminal
Movement from enable mode to global configuration mode by using the __ EXEC command.
Global
first mode after configure terminal: hostname(config)#
Line
hostname(config-line)#
Interface
hostname(config-if)#
VLAN
hostname(vlan)#
exit
You can also move directly from one configuration submode to another, without first using the __ command to move back to global configuration mode.
global command
The hostname command is a __ because there is only one host name per switch.
interface subcommand
The duplex command is an __ to allow the switch to use a different setting on the different interfaces.
random-access memory
Cisco switches contain __ to store data while Cisco IOS is using it, but it loses its contents when the switch loses power.
RAM
__ is used by the switch just as it is used by any other computer: for working storage. The running (active) configuration file is stored here.
ROM
__ stores a bootstrap (or boothelper) program that is loaded when the switch first powers on.
flash memory
Either a chip inside the switch or a removable memory card, __ stores fully functional Cisco IOS images and is the default location where the switch gets its Cisco IOS at boot time.
Nonvolatile RAM
__ stores the initial or startup configuration file that is used when the switch is first powered on and when the switch is reloaded.
Startup config
Stores the initial configuration used anytime the switch reloads Cisco IOS.
Running config
Stores the currently used configuration commands. This file changes dynamically when someone enters commands in configuration mode.
running config
Essentially, when you use configuration mode, you change only the __ file.
startup config
If you want to keep that configuration, you have to copy the running config file into NVRAM, overwriting the old __ file.
reload
Cisco uses the term __ to refer to what most PC operating systems call rebooting or restarting.
copy running-config startup-config
If you want to keep the new configuration commands you add in configuration mode (so that the changes are present the next time the system is rebooted), you need to use the command __.
copy, RAM, NVRAM, TFTP server
The most basic method for moving configuration files in and out of a switch is to use the __ command to copy files between __ or __ on a switch and a __.
copy {tftp | running-config | startup-config} {tftp | running-config | startup-config}
The commands for copying Cisco IOS configurations can be summarized as follows:
from, to
In copy command, the first set of parameters enclosed in braces ({ }) is the “__” location; the next set of parameters is the “__” location.
replaces
The copy command always __ the existing file when the file is copied into NVRAM or into a TFTP server.
merged
When the copy command copies a configuration file into the running config file in RAM, the configuration file in RAM is not replaced, but is __ instead.
reload
One way to guarantee that the two configuration files match is to issue the __ command, which reboots, the switch, which erases RAM and then copies the startup config into RAM as part of the reload process.
write erase, erase startup-config, erase nvram
You can use three different commands to erase the contents of NVRAM. The __ and __ commands are older, whereas the __: command is the more recent, and recommended, command.
startup config, reload
Cisco IOS does not have a command that erases the contents of the running config file. To clear out the running config file, simply erase the __ file and then __ the switch.
configuration mode, setup mode
Cisco IOS Software supports two primary methods of giving a switch an initial basic configuration: __ and __.
Setup mode
__ leads a switch administrator by asking questions that prompt the administrator for basic configuration parameters.
setup
When a Cisco switch or router initializes, but the startup config file is empty, the switch or router asks the console user if he wants to use __.
show version
The __ command does list information about the IOS, including the version of IOS software and many other interesting facts as well.
line console 0
Global command that changes the context to console configuration mode.
line vty 1st-vty last-vty
Global command that changes the context to vty configuration mode for the range of vty lines listed in the command.
login
Line (console and vty) configuration mode. Tells IOS to prompt for a password (no username).
password pass-value
Line (console and vty) configuration mode. Lists the password required if the login command (with no other parameters) is configured.
interface type port-number
Global command that changes the context to interface mode—for example, interface FastEthernet 0/1.
hostname name
Global command that sets this switch’s host name, which is also used as the first part of the switch’s command prompt.
exit
Moves back to the next higher mode in configuration mode.
end
Exits configuration mode and goes back to enable mode from any of the configuration submodes.
Ctrl+Z
This is not a command, but rather a two-key combination that together do the same thing as the end command.