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This chapter explains how to configure lines, modems, and terminal settings. The LightStream 1010 ATM switch has two types of terminal lines: a console line and an auxiliary line. Most line setup is the same for all types of lines, but certain commands, such as those having to do with modem control and Serial Line Internet Protocol (SLIP)/Point-to-Point Protocol (PPP) support, apply to the auxiliary port only.
The following sections describe line configuration tasks. For line configuration, you must first set up the lines for the terminals or other asynchronous devices attached to them. The parameters for each line are configured next. However, the tasks you perform and the order in which you perform them are determined entirely by the requirements of your network environment.
Perform one or more of the tasks in the following sections to configure your LightStream 1010 line connections:
Line configuration mode is used to set the terminal-specific parameters. From line configuration mode, you can enter line configuration commands that affect the auxiliary or console port line you have specified. To enter line configuration mode, complete the following task:
| Task | Command |
|---|---|
At the privileged EXEC prompt, enter configuration mode from the terminal. | |
From global configuration mode, begin to configure an auxiliary, console, or virtual terminal line. | line [aux | console | vty] line-number [ending-line-number] |
| 1This command is documented in the LightStream 1010 ATM Switch Command Reference (11.2) publication. |
To configure line parameters for the auxiliary port in the preceding task, enter the following:
Switch(config)# line aux 0
The auxiliary relative line number must be 0. See the modem line configuration commands in the section "Set Up Modem Control on the Auxiliary Port" later in this chapter to set up modem support on the auxiliary port.
The terminal from which you locally configure the LightStream 1010 ATM switch is attached to the console port. To configure line parameters for the console port in the preceding task, you enter the following:
Switch(config)# line con 0
The console relative line number must be 0.
Configuring the console port or virtual terminal lines allows you to specify communication parameters, and autobaud connections, and configure terminal operating parameters for the terminal you are using. These tasks are described in the section "Define Terminal Operation Characteristics."
The following example shows how to create and configure the maximum 4 virtual terminal lines with the "no login" feature:
Switch(config)# line vty 0 4 Switch(config-line)# no login
The following example shows how to eliminate virtual terminal line 4 and all higher-numbered virtual terminal lines. Only virtual terminal lines 0 to 3 remain.
Switch(config)# no line vty 4
The LightStream 1010 ATM switch supplies default serial communication parameters for terminal and other serial device operation. You can change these parameters to meet the requirements of the terminal or host to which you are attached. To do so, perform one or more of the following tasks in line configuration mode:
| Task | Command |
|---|---|
Set the line speed. Choose from line speed, transmit speed, or receive speed. Speed applies to the auxiliary port only. | |
Set the data bits. | databits {5 | 6 | 7 | 8} |
Set the stop bits. | stopbits {1 | 1.5 | 2} |
parity {none | even | odd | space | mark} |
The following example shows how to configure the auxiliary line with a speed of 19,200 bits per second (bps):
Switch(config)# line aux 0
Switch(config-line)# speed 19200
You can configure a terminal to automatically detect the baud rate over an asynchronous serial line. This command applies to the auxiliary port only. To set up automatic baud detection, perform the following task in line configuration mode:
| Task | Command |
|---|---|
Set the terminal to automatically detect the baud rate. |
To start communications using automatic baud detection, press Return multiple times at the terminal. Press Return three times for 600-, 1800-, or 19200-baud line to detect the baud rate; Press Return twice to set up a line at any other baud rate. Press Return after the baud rate is detected, and the EXEC simply displays another system prompt.
To change the default privilege level for a given line or group of lines, perform the following task in line configuration mode:
| Task | Command |
|---|---|
Specify a default privilege level for a line. |
| 1This command is documented in the LightStream 1010 ATM Switch Command Reference (11.2) publication. |
On the auxiliary port, you can set both hardware and software flow control between the LightStream 1010 ATM switch and the devices attached to it. Both types of flow control are bidirectional. When you specify software flow control, an additional keyword specifies the direction: in causes the LightStream 1010 ATM switch to listen to flow control from the attached device, and out causes the LightStream 1010 ATM switch to send flow control information to the attached device. If you do not specify a direction, the LightStream 1010 ATM switch enables software flow control in both directions.
For software flow control, the default stop and start characters are Ctrl-S and Ctrl-Q (XOFF and XON), respectively. However, you can define characters or character sequences that signal the start and end of data transmission when software flow control is in effect. This capability is useful for providing data control over the serial line.
You can also specify hardware flow control. For information about setting up the EIA/TIA-232 line, see the hardware installation and maintenance manual for your product.
To configure flow control between the LightStream 1010 ATM switch and attached device, perform one or more of the following tasks in line configuration mode:
| Task | Command |
|---|---|
Set the terminal flow control. | flowcontrol {none | software [in | out] | hardware [in | out]} |
Set the flow control start character. | start-character ascii-number |
Set the flow control stop character. | stop-character ascii-number |
You can define a command that will automatically execute upon connection to another host. Any appropriate EXEC command and any switch or host name that occurs with the EXEC command is allowed. To do so, perform the following task in line configuration mode:
| Task | Command |
|---|---|
Define a command string to be automatically executed. | autocommand command |
You can specify the protocols for individual lines by setting the protocol for incoming and outgoing connections and changing the default (preferred) protocol for a line. The default transport protocol is Telnet.
Select the command to use based on whether it is for incoming or outgoing connections or is being used as a default (preferred) selection.
Perform one or more of the following tasks in line configuration mode to specify transport protocols:
| Task | Command |
|---|---|
Define which protocols can connect to a specific line of the LightStream 1010 ATM switch. | transport input {all | telnet | none} |
Determine the protocols for outgoing connections from a line. | transport output {all | telnet | none} |
Specify the protocol to use if the user did not specify one. | |
Prevent errant connection attempts. |
The system accepts a host name entry at the EXEC system prompt as a Telnet command. If you mistype the host name, the system interprets the entry as an incorrect Telnet command and displays an error message indicating that the host does not exist. The transport preferred none command disables this option if you mistype a command at the EXEC prompt, the system will not attempt to make a Telnet connection.
You might need to control terminal sessions in high-traffic areas to provide resources for all users. You can define these limitations for terminal sessions:
To control terminal sessions, perform one or more of the following tasks in line configuration mode:
| Task | Command |
|---|---|
Set the maximum number of sessions. | |
Set the idle session timeout interval. or Set the absolute timeout interval. | session-timeout minutes [output] or absolute-timeout minutes |
Warn users of impending timeouts set with the absolute-timeout command. | logout-warning [seconds] |
You can configure modem control on the auxiliary port of the LightStream 1010 ATM switch. The auxiliary port is a standard EIA/TIA DB-25 connector. Table 3-1list s the auxiliary port output and input signals.
| Pin | Signal | Direction | Description |
2 | TxD | ---> | Transmit data |
3 | RxD | <--- | Receive data |
4 | RTS | ---> | Request to send (used for hardware flow control) |
5 | CTS | <--- | Clear to send (used for hardware flow control) |
6 | DSR | <--- | Data set ready |
7 | Signal ground | -- | Signal ground |
8 | CD | <--- | Carrier detect (used for modem control) |
20 | DTR | ---> | Data terminal ready (used for modem control only) |
Configure modem control on the LightStream 1010 ATM switch by performing the tasks in this section:
Figures in the following sections illustrate how modem control works. The diagrams show two processes:
In the figures, the current signal state and the signal line are listed inside each box. The state of the line (as displayed by the EXEC command show line) is listed next to the box. Events that change that state appear in italics along the event path, with the software actions described within the ovals.
Figure 3-1 illustrates line behavior when no modem control is set. The DTR output is always high, and CTS and RING are ignored. The LightStream 1010 ATM switch creates an EXEC when the activation character is typed. Incoming Transmission Control Protocol (TCP) connections occur instantly if the line is not in use and can be closed only by the remote host.
With the dialup capability, you can set a modem to automatically dial the phone number of a remote LightStream 1010 ATM switch. This feature offers cost savings because phone line connections are made as needed. You only pay for using the phone line when there is data to be received or sent. To configure a line for automatic dialing, perform the following task in line configuration mode:
| Task | Command |
|---|---|
Configure a line to initiate automatic dialing. |
You can configure a line to close all connections from a user's terminal when the terminal is turned off, and prevent inbound connections to devices that are out of service. To do so, perform the following task in line configuration mode:
| Task | Command |
|---|---|
Configure a line to close all connections. |
Figure 3-2 illustrates the modem cts-required process requires a high CTS throughout the use of the line. If CTS is not high, the user's typed input is ignored and incoming connections are refused (or stepped to the next line in a rotary group).
You can configure a line to automatically answer a modem. You would also configure the modem to do the following:
Wire the modem's CD signal (generally pin 8) to the RING input (pin 22) of the LightStream 1010 ATM switch, then perform the following task in line configuration mode:
| Task | Command |
|---|---|
Configure a line to automatically answer a modem. |
You can turn on the modem's hardware flow control independently to act on the status of the LightStream 1010 ATM switch's CTS input. Wire CTS to whatever signal the modem uses for hardware flow control. If the modem expects to control hardware flow in both directions, you might also need to wire the modem's flow control input to some other signal that the LightStream 1010 ATM switch always has high (such as DTR).
Figure 3-3 illustrates the modem ri-is-cd process. When the LightStream 1010 ATM switch detects a signal on the RING input of an idle line, it starts an EXEC or autobaud process on that line. If the RING signal disappears on an active line, the LightStream 1010 ATM switch closes any open network connections and terminates the EXEC. If the user exits the EXEC or the LightStream 1010 ATM switch terminates it because of no user input, the line hangs up the modem by lowering the DTR signal for five seconds. After five seconds, the modem is ready to accept another call.
The LightStream 1010 ATM switch supports dial-in modems that use DTR to control the off-hook status of the telephone line. To do this, perform the following task in line configuration mode:
| Task | Command |
|---|---|
Configure a line for a dial-in modem. |
Figure 3-4 illustrates the modem callin process. When a modem dialing line is idle, the DTR is in a low state and waits for a transition to occur on the RING input. This transition causes the line to raise DTR and start watching the CTS signal from the modem. After the modem raises CTS, the LightStream 1010 ATM switch creates an EXEC on the line. If the timeout interval (set with the modem answer-timeout command) passes before the modem raises CTS, the line lowers DTR and returns to the idle state.
Although you can use the modem callin line configuration command with newer modems, the modem ri-is-cd line configuration command described earlier in this section is more appropriate. The modem ri-is-cd command frees up CTS for hardware flow control. Modern modems do not require the DTR to take a phone line off hook.
The LightStream 1010 ATM switch supports ports connected to computers that are connected to modems. You can configure the LightStream 1010 ATM switch to behave somewhat like a modem by performing the following task in line configuration mode. This command also prevents incoming calls.
| Task | Command |
|---|---|
Configure a line for reverse connections and prevent incoming calls. |
Figure 3-5 illustrates the modem callout process. When the LightStream 1010 ATM switch receives an incoming connection, it raises DTR and waits to see if the CTS becomes high, indicating that the host has noticed its signal. If the host does not respond within the interval set with the modem answer-timeout subcommand, the LightStream 1010 ATM switch lowers DTR and drops the connection.
You can configure a line for both incoming and outgoing calls by performing the following task in line configuration mode:
| Task | Command |
|---|---|
Configure a line for both incoming and outgoing calls. |
Figure 3-6 illustrates the modem in-out process. If the line is activated by raising RING, it behaves exactly as a line configured with the modem ri-is-cd subcommand described previously. If the line is activated by an incoming TCP connection, the line behaves similarly to a nonmodem line.
You can change the interval that the LightStream 1010 ATM switch waits for CTS after raising DTR in response to RING from the default of 15 seconds. To do so, perform the following task in line configuration mode. The timeout applies to the modem callin command only.
| Task | Command |
|---|---|
Configure modem line timing. | modem answer-timeout seconds |
Connections can be made to the next free line in a group of lines, also called a rotary or hunt group. A line can be in only one rotary group; a rotary group can consist of a single line or several contiguous lines. The console line (line 0) cannot be in a rotary group.
You might want to assign the rotary with the single auxiliary port line since the auxiliary port is not necessarily the same line number on all hardware. By putting it in a rotary group, you do not have to track the actual line number. Another reason to use a rotary group is that if the device supports local area transport (LAT), an inbound service can only be bound to a rotary group; it cannot be bound to a port number.
To configure a rotary group, perform the following task in line configuration mode:
| Task | Command |
|---|---|
Add a line to the specified rotary group. | rotary group |
You can configure automatic line disconnect by performing the following task in line configuration mode:
| Task | Command |
|---|---|
Configure automatic line disconnect. |
The autohangup command causes the EXEC to issue the exit command when the last connection closes. This feature is useful for UNIX-to-UNIX Copy Program (UUCP) applications that require this behavior, since UUCP scripts cannot issue the command that hangs up the telephone.
Dial-up modems that operate over normal dial-up telephone lines at speeds of 9600 bits per second (bps) and higher are now available. These modems do not operate at a guaranteed throughput; instead, they operate at a speed that depends on the quality of the line, the effectiveness of data compression algorithms on the data being transmitted, and other variables. These modems use hardware flow control to stop the data from reaching the host by toggling an EIA/TIA-232 signal when they cannot accept any more data.
In addition to hardware flow control, dial-up modems require special software handling. You must configure the modems to create an EXEC when a user dials in, hang up when the user exits the EXEC, and close any existing network connections if the telephone line hangs up in the middle of a session.
Your LightStream 1010 ATM switch supports hardware flow control on its CTS input, which is also used by the normal modem handshake.
Perform the following tasks to configure and use a high-speed modem:
| Task | Command |
|---|---|
Step 1 In line configuration mode, enable outgoing hardware flow control based on the CTS input. | |
Step 2 In EXEC mode, display informational messages, on the console terminal, about modem control events, such as signal transitions and autobaud progress. | |
Step 3 In EXEC mode, display the status of a line. In the detailed command output, a Status line with "Idle" identifies inactive modem ri-is-cd lines and all other modem lines; a Status line with "Ready" identifies lines in use. |
| 1This command is documented in the LightStream 1010 ATM Switch Command Reference (11.2) publication. |
The LightStream 1010 ATM switch can receive incoming connections on the auxiliary port. This capability allows you to attach serial printers, modems, and other shared peripherals to the LightStream 1010 ATM switch and drive them remotely from other systems. The LightStream 1010 ATM switch supports reverse TCP connections.
The specific TCP port or socket to which you attach the peripheral device determines the type of service the LightStream 1010 ATM switch provides on that line. When you attach the serial lines of a computer system or a data terminal switch to the auxiliary port of the LightStream 1010 ATM switch, the LightStream 1010 ATM switch acts as a network front end for a host that does not support the TCP/IP protocols. This arrangement is sometimes called front-ending or reverse connection mode.
To connect the auxiliary port, the remote host or terminal must specify a particular TCP port on the LightStream 1010 ATM switch. If Telnet protocols are required, that port is 2000 (decimal) plus the decimal value of the line number.
If a raw TCP stream is required, the port is 4000 (decimal) plus the decimal line number. The raw TCP stream is usually the required mode for sending data to a printer.
The Telnet protocol requires that carriage return characters are translated into carriage return and linefeed character pairs. You can turn this translation off by specifying the Telnet binary mode option. To specify this option, connect to port 6000 (decimal) plus the decimal line number.
In line configuration mode, you can set terminal operation characteristics for that line until you change the line parameters.
You can temporarily change the line settings with the terminal EXEC commands described in the chapter "Understanding the User Interfaces for the LightStream 1010 ATM Switch."
Define the terminal operation characteristics by performing the following tasks:
You can specify the type of terminal connected to a line. This feature has two benefits: it records the type of terminal attached to a line, and it can inform the remote host of the terminal type for display management. To specify the terminal type, perform the following task in line configuration mode:
| Task | Command |
|---|---|
Specify the terminal type. | terminal-type terminal-name |
By default, the LightStream 1010 ATM switch provides a screen display of 24 lines by 80 characters. You can reconfigure these values if they do not meet the needs of your terminal by performing the following tasks in line configuration mode:
| Task | Command |
|---|---|
Set the screen length. | length screen-length |
Set the screen width. | width characters |
The values set can be learned by some host systems that use this type of information in terminal negotiation. Set a value of zero for the screen length to disable pausing between screens of output.
You can define or modify the default key sequences to execute functions for system escape, terminal activation, disconnect, and terminal pause. To define or change the default sequence, perform one or more of the following tasks in line configuration mode:
| Task | Command |
|---|---|
Change the system escape sequence. The escape sequence indicates that the codes that follow have special meaning. The default sequence is Ctrl-^. | escape-character ascii-number |
Define a session activation sequence or character. Typing this sequence at a vacant terminal begins a terminal session. The default key is Return. | activation-character ascii-number |
Define the session disconnect sequence or character. Typing this sequence at a terminal ends the session with the LightStream 1010 ATM switch. There is no default sequence. | disconnect-character ascii-number |
Define the hold sequence or character that causes output to the terminal screen to pause. There is no default sequence. To continue the output, type any character after the hold character. To use the hold character in normal communications, precede it with the escape character. | hold-character ascii-number |
You can reinstate the default value for the escape character or activation character by using the no form of the command. For example, issuing the no escape-character line configuration command returns the escape character to Ctrl-^.
You can use a 7-bit character set (such as ASCII) or you can enable a full 8-bit international character set (such as ISO 8859) to allow special graphical and international characters for use in banners and prompts, and to add special characters such as software flow control. You can configure these settings globally by interface or locally at the user level. Use the following criteria for determining the configuration mode to use when setting up this feature:
To specify a character set on a global basis, perform one or both of the following tasks in global configuration mode:
| Task | Command |
|---|---|
Specify the character set used in EXEC and configuration command characters. | |
Specify the character set used in special characters such as software flow control, hold, escape, and disconnect characters. |
To specify a character set based on hardware or software, or on a per-line basis, perform the appropriate task in line configuration mode, as follows:
| Task | Command |
|---|---|
Set the number of databits per character that are generated and interpreted by hardware. | databits {5 | 6 | 7 | 8} |
Set the number of databits per character that are generated and interpreted by software. | data-character-bits {7 | 8} |
Specify the character set used in EXEC and configuration command characters on a per-line basis. | exec-character-bits {7 | 8} |
Specify the character set used in special characters such as software flow control, hold, escape, and disconnect characters on a per-line basis. | special-character-bits {7 | 8} |
You can change the character padding on a specific output character. Character padding adds a number of null bytes to the end of the string and can make a string conform to an expected length. To set character padding, perform the following task in line configuration mode:
| Task | Command |
|---|---|
Set padding on a specific output character for the specified line. | padding ascii-number count |
To disable enhanced editing mode and revert to the editing mode of previous software releases, perform the following task in line configuration mode:
| Task | Command |
|---|---|
Disable the enhanced editing features for a particular line. |
| 1This command is documented in the LightStream 1010 ATM Switch Command Reference (11.2) publication. |
You might disable enhanced editing if you have prebuilt scripts that do not interact well when enhanced editing is enabled. You can reenable enhanced editing mode with the editing command.
You can provide the host name, line number, and location each time an EXEC is started or an incoming connection is made. The line number banner, which appears immediately after the EXEC banner or incoming banner. It is useful for tracking problems with modems because it lists the host and line for the modem connection. Modem information is also included if applicable.
To provide service line number information, perform the following task in global configuration mode:
| Task | Command |
|---|---|
Provide service line number information after the EXEC or incoming banner. | service linenumber |
You can enable password checking on a particular line so that the user is prompted to enter a password at the system login screen. You must then also specify a password. Perform the following tasks in line configuration mode:
| Task | Command |
|---|---|
Step 1 Enable password checking on a per-line basis using the password specified with the password command. | |
Step 2 Assign a password to a particular line. | password password |
You can enable password checking on a per-user basis so that authentication is based on the username specified with the username global configuration command, as described in the "Configuring System Management Functions" chapter. To enable this type of password checking, perform one of the following tasks in line configuration mode:
| Task | Command |
|---|---|
Enable password checking on a per-user basis using the username and password specified with the username global configuration command. | |
Select the TACACS-style user ID and password-checking mechanism. | login tacacs |
Use the login tacacs command with Terminal Access Controller Access Control System (TACACS) and extended TACACS Plus. Use the login authentication command with authentication authorization, and accounting (AAA)/TACACS+.
By default, virtual terminals require passwords. If you do not set a password for a virtual terminal, it responds to attempted connections by displaying an error message and closing the connection. Use the no login command to disable this behavior and allow connections without a password.
For other access control tasks and password restrictions, including the enable password global configuration command that restricts access to privileged mode, see the "Configuring System Management Functions" chapter.
The following example shows password checking enabled for a virtual terminal line 1:
Switch(config)# line vty 1
Switch(config-line)# login
Switch(config-line)# password letmein
The following example shows password checking enabled on a per-user basis:
Switch(config)# username jksmith password 0 letmein
Switch(config)# username lmjones password 0 littlerock
Switch(config)# line vty 1
Switch(config-line)# login local
Configure the following types of messages by performing one or more of the following tasks:
The following sections explain how to configure these messages and how to suppress display of the message-of-the-day (MOTD) and line activation banners.
You can configure MOTD to display on all connected terminals. This message is displayed at login and is useful for sending messages that affect all network users, such as impending system shutdowns. To do so, perform the following task in global configuration mode:
| Task | Command |
|---|---|
Configure a message-of-the-day banner. | banner motd c message c |
You can configure a line activation message to display when an EXEC process such as line activation or an incoming connection to a virtual terminal is created. To do so, perform the following task in global configuration mode:
| Task | Command |
|---|---|
Configure a message to be displayed on terminals with an interactive EXEC. | banner exec c message c |
You can configure a message to display on terminals connected to reverse Telnet lines. This message is useful for providing instructions to users of these types of connections. Reverse Telnet connections are described in more detail in the section "Support Reverse TCP Connections" earlier in this chapter.
To configure the message that will be sent on incoming connections, perform the following task in global configuration mode:
| Task | Command |
|---|---|
Configure messages to display on terminals connected to reverse Telnet lines. | banner incoming c message c |
You can configure messages to display on a console or terminal that is not in use. Also called a vacant message, this message is different from the banner message displayed when an EXEC process is activated. To configure an idle terminal message, perform the following task in line configuration mode:
| Task | Command |
|---|---|
Display an idle terminal message. | vacant-message [c message c] |
You can control display of the MOTD and line activation banners. By default, these banners display on all lines. To suppress or resume these messages, perform one of the following tasks in line configuration mode:
| Task | Command |
|---|---|
Suppress banner display. | no exec-banner |
Resume the display of the EXEC or MOTD banners. |
The following example shows how to use the banner global configuration command and
no exec-banner line configuration command to notify your users that the server is going to be reloaded with new software:
Switch(config)# banner exec /
Enter TEXT message. End with the character '/'. This is the Cisco System Publications and Training LS1010 Switch Unauthorized access prohibited./ Switch(config)# banner incoming /
You are connected to a Hayes-compatible modem. Enter the appropriate AT commands. Remember to reset anything to change before disconnecting. / Switch(config)# banner motd /
The switch will go down at 6pm for a software upgrade / Switch(config)# line vty 0 4
Switch(config-line)# no exec-banner
Switch(config-line)#
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