Table Of Contents
Configuring the Cisco PAD Facility for X.25 Connections
Cisco PAD EXEC User Interface Connections
Cisco Universal X.28 PAD Emulation Mode
X.3 PAD EXEC User Interface Configuration Task List
Monitoring X.25 PAD Connections
X.28 PAD Emulation Configuration Task List
Accessing X.28 Mode and Setting Options
Exchanging PAD Command Signals
Accepting Reverse or Bidirectional X.25 Connections
Setting PAD French Language Service Signals
Making X.25 PAD Calls over IP Networks
PAD EXEC User Interface Connection Examples
X.3 Parameter Customization Example
Cisco Universal X.28 PAD Emulation Mode Examples
Set Parameters Using X.28 PAD Emulation Mode Example
X.25 Call Detail Display Example
Set PAD French Service Signals in X.28 Mode Example
Set PAD French Service Signals with an X.29 Profile Example
Accept XOT to PAD Connections Example
Accept XOT to Protocol Translation Example
Initiate a PAD Call over an XOT Connection Example
Address Substitution for PAD Calls Example
Configuring the Cisco PAD Facility for X.25 Connections
This chapter describes how to use the internal packet assembler/disassembler (PAD) facility to make connections with remote devices over the X.25 protocol. This chapter includes the following sections:
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X.3 PAD EXEC User Interface Configuration Task List
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Table 1 in this chapter summarizes the X.3 PAD parameters that you can set. For a complete description of each X.3 parameter supported by the standard X.28 mode or Cisco PAD EXEC user interface, see the appendix "X.3 PAD Parameters" at the end of this publication.
For a complete description of the commands in this chapter, refer to the Cisco IOS Terminal Services Command Reference, Release 12.2. To locate documentation of other commands that appear in this chapter, use the command reference master index or search online.
To identify the hardware platform or software image information associated with a feature, use the Feature Navigator on Cisco.com to search for information about the feature or refer to the software release notes for a specific release. For more information, see the "Identifying Supported Platforms" section in the "Using Cisco IOS Software" chapter.
PAD Connection Overview
PADs are configured to enable X.25 connections between network devices. A PAD is a device that receives a character stream from one or more terminals, assembles the character stream into packets, and sends the data packets out to a host. A PAD can also do the reverse. It can take data packets from a network host and translate them into a character stream that can be understood by the terminals. A PAD is defined by Recommendations X.3, X.28, and X.29 of the International Telecommunication Union Telecommunication Standardization Sector (ITU-T). (The ITU supersedes the Consultative Committee for International Telegraph and Telephone, or CCITT).
Figure 1 shows a remote X.25 user placing a call through an X.25 switched network to the internal PAD application on a Cisco 4700-M router, and to an X.25 host located inside a corporate data center.
Figure 1 Standard X.25 Connection Between a Dumb Terminal and an X.25 Host
PADs can also be configured to work with a protocol translation application. Figure 2 shows an example of a remote PC placing an analog modem call to an IP network, connecting to a Cisco 4500-M router, and allowing its IP packets to undergo IP-to-X.25 protocol translation. The remote PC, in turn, communicates with an internal PAD device in the Cisco router and establishes a connection with an X.25 host.
Figure 2 PC Dialing In to an X.25 Host Using Protocol Translation
Cisco IOS offers two ways of connecting to a PAD: using the pad EXEC user interface command to initiate an outgoing connection to a PAD, and using the x28 EXEC command to access the Cisco universal X.28 PAD user emulation mode.
In X.28 PAD user emulation mode, you can perform the same functions available from the Cisco pad EXEC user interface; however, X.28 PAD user emulation mode adds functionality such as the ability to exchange PAD signals across an X.25 network, and is useful for connecting to systems using software designed to interact with an X.28 PAD. X.28 PAD user emulation mode is also useful when a reverse connection requires packetization according to the X.29 parameters.
Cisco PAD EXEC User Interface Connections
The Cisco IOS pad EXEC user interface initiates an outgoing call to a PAD host and in most cases is the preferred PAD connection method. You can have multiple PAD connections open at one time. Options are available for pausing and resuming connections, and setting X.3 PAD parameters at the command line.
Cisco Universal X.28 PAD Emulation Mode
The Cisco IOS software provides a universal X.28 user emulation mode that enables you to interact with and control the PAD. X.28 emulation effectively turns the Cisco router into an X.28-compliant PAD device that provides a standard user interface between a DTE device and a PAD.
For asynchronous devices such as terminals or modems to access an X.25 network host, the packets from the device must be assembled or disassembled by a PAD. Using standard X.28 commands from the PAD, calls can be made into an X.25 network, X.3 PAD parameters can be set, or calls can be reset.
X.3 is the ITU-T recommendation that defines various PAD parameters used in X.25 networks. X.3 PAD parameters are internal variables that define the operation of a PAD. For example, parameter 9 is the crpad parameter. It determines the number of bytes to add after a carriage return. X.3 parameters can also be set by a remote X.25 host using X.29. (See Figure 3.)
Figure 3 Asynchronous Device Dialing In to an X.25 Host over an X.25 Network
Note
X.28 enables PAD system administrators to dial in to X.25 networks or set PAD parameters using the X.28 standard user interface. This standard interface is commonly used in many European countries. It adheres to the X.25 ITU-T standards.
The X.28 interface is designed for asynchronous devices that require X.25 transport to access a remote or native asynchronous or synchronous host application. For example, dialup applications can use the X.28 interface to access a remote X.25 host. X.28 PAD calls are often used by banks to support applications in the "back office" such as ATM machines, point of sales authorization devices, and alarm systems. An ATM machine may have an asynchronous connection to an alarm host and a Cisco router. When the alarm is tripped, the alarm sends a distress call to the authorities via the Cisco router and an X.28 PAD call.
Cisco X.28 PAD calls can be transported over a public packet network, a private X.25 network, the Internet, a private IP-based network, or a Frame Relay network. X.28 PAD can also be used with protocol translation. Protocol translation and virtual asynchronous interfaces enable users to bidirectionally access an X.25 application with the PAD service or other protocols such as Digital, local-area transport (LAT), and TCP.
X.3 PAD EXEC User Interface Configuration Task List
To connect to a PAD using the EXEC user interface, perform the following tasks:
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Making a PAD Connection
To log in to a PAD, use the following command in EXEC mode:
Router> pad {x121-address | hostname} [/cud text] [/debug] [/profile name] [/quiet message] [/reverse] [/use-map]
Logs in to a PAD.
You can exit a connection and return to the user EXEC prompt at any point.
To open a new connection, first exit the current connection by entering the escape sequence (Ctrl-Shift-6 then x [Ctrl^x] by default) to return to the EXEC prompt.
Switching Between Connections
You can have several concurrent sessions open and switch between them. The number of sessions that can be open is defined by the session-limit command, which is described in the Cisco IOS Terminal Services Command Reference, Release 12.2.
To switch between sessions by escaping one session and resuming a previously opened session, use the following commands in EXEC mode:
Note
Exiting a PAD Session
To exit a PAD session, enter the escape sequence (Ctrl-Shift-6 then x [Ctrl^x] by default) and enter the disconnect command at the EXEC prompt. You can also log out of the remote system by entering the command specific to that system (such as exit, logout, quit, close, or disconnect).
Monitoring X.25 PAD Connections
To display information about current open connections, use the following command in user EXEC mode:
The information displayed by show x25 pad includes packet transmissions, X.3 parameter settings, and the current status of virtual circuits. The information displayed will help you set and change PAD parameters (see the section "X.3 Parameter Customization Example" for an example).
Setting X.3 PAD Parameters
To set X.3 PAD parameters, use one of the following commands in EXEC mode:
or
Router> x3 parameter:valueSets X.3 PAD parameters.
Table 1 summarizes the X.3 PAD Parameters supported on Cisco devices. See the "X.3 PAD Parameters" appendix in this publication for more complete information about these parameters. Refer to the "ASCII Character Set and Hex Values" appendix in the Cisco IOS Configuration Fundamentals Command Reference, Release 12.2, for a list of ASCII characters.
X.28 PAD Emulation Configuration Task List
To use the X.28 PAD mode, perform the following tasks as needed:
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The section "Cisco Universal X.28 PAD Emulation Mode Examples" provides examples of making X.28 PAD connections.
Accessing X.28 Mode and Setting Options
To access the Cisco IOS universal X.28 emulation mode, use the x28 EXEC command. This mode can also be accessed with the autocommand line configuration command. The autocommand command can be assigned to a particular line, range of lines, or login user ID. In this case, when a user connects to the line, the user sees an X.28 interface. Using the noescape option with the autocommand feature blocks users from getting into EXEC mode.
The default X.28 router prompt is an asterisk (*). After you see *, the standard X.28 user interface is available. You configure the PAD in this mode.
To enter X.28 mode and set different access and display parameters, use the following commands in EXEC mode:
Router> x28 escape character-string
Specifies a character string to use to exit X.28 mode and return to EXEC mode. This string becomes an added command to X.28 mode that, when entered by the user, terminates X.28 mode and returns to EXEC mode. The default escape string is exit.1
Router> x28 nuicud
Places the data entered in the network user identification (NUI) facility by the user into the Call User Data (CUD) field of the X.25 call request packet.2
Router> x28 profile file-name
Specifies a user-defined X.3 profile. If this option is specified, with a profile name, then the profile is used as the initial set of X.3 parameters.3
Router> x28 reverse
Reverses the charges of all calls dialed by the local router. The address of the destination device is charged for the call. This is the default configuration. Every call is placed with the reverse charge request set.
Router> x28 verbose
Displays detailed information about the X.25 call connection (for example, address of the remote DTE device and the facility block used).
1 If the x28 noescape command is set, then it is impossible to return to the EXEC mode from X.28 mode. Use with caution. This command is not accepted when using the console line.
2 Upon entry of the x28 nuicud command, the network user (NU) data will not be placed in the NUI facility of the call request. Instead it will be placed in the CUD field. If you configure the x28 nuicud command, all reverse charging requests set by the x28 reverse command are disabled.
3 Profiles are created with the x29 profile EXEC command. If the X.29 profile is set to default, the profile is applied to all incoming X.25 PAD calls, including the calls used for protocol translation.
Exchanging PAD Command Signals
The Cisco IOS universal X.28 emulation mode allows you to interact with and control the PAD. During an exchange of control information, messages or commands sent from the terminal to the PAD are called PAD command signals. Messages sent from the PAD to the terminal are called PAD service signals.
Many X.25-related functions can be performed in X.28 mode by exchanging PAD signals, such as placing and clearing calls. Table 2 lists the PAD X.28 command signals supported in the Cisco universal X.28 emulation mode.
Table 2 Available PAD Command Signals
break
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Simulates an asynchronous break.
call
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Places a virtual call to a remote device.
command-signal
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Specifies a call request without using a standard X.28 command, which is entered with the following syntax: facilities-x121-addressDcall-user-data. The hyphen (-) and "D" are required keywords.
clr
clear
Clears a virtual call.
help
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Displays help information.
iclr
iclear
Requests the remote device to clear the call.
int
interrupt
Sends an Interrupt packet.
par?
parparameter read
Displays the current values of local parameters.
prof
profile file-name
Loads a standard or named profile.
reset
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Resets the call.
rpar?
rread
Displays the current values of remote parameters.
rset?
rsetread
Sets and then reads values of remote parameters.
set
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Changes the values of local parameters. (See the "Customizing X.3 Parameters" section later in this chapter.)
set?
setread
Changes and then reads the values of parameters.
stat
status
Requests status of a connection.
selection pad
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Sets up a virtual call.
Note
Placing a Call
To place a call to another X.25 destination, you specify the destination X.121 address optionally preceded by facility requests and optionally followed by CUD. As of Cisco IOS Release 12.0, Cisco only supports the reverse charge and NUI facilities.
To place a call, use the following commands in EXEC mode:
Step 1
Router> x28
Enters X.28 mode. An asterisk prompt appears.
Step 2
* call address
Dials the address of the remote interface.
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Clearing a Call
To clear a connection after you connect to a remote X.25 device, use the following commands in EXEC mode:
Step 1
* Ctrl-p
From the remote host, escapes back to the local router.
Step 2
Router> clr
Clears the virtual call.
Customizing X.3 Parameters
To set an X.3 PAD parameter from a local terminal, use the following commands in EXEC mode:
See Table 1 and the"X.3 PAD Parameters" appendix at the end of this publication for more information.
Accepting Reverse or Bidirectional X.25 Connections
Active lines operating in X.28 mode can receive incoming calls from the network, if they do not already have an active call. The user is notified of the call by the X.28 incoming call service signal. This feature extends the traditional capability of reverse PAD connections, which could only be received on lines that were not active.
The criteria to choose the line the call is intended for are the same as for reverse PAD connections. (The rotary is chosen from the subaddress portion of the destination address.) Because the normal rotary selection mechanism (which checks whether lines have an active EXEC) takes precedence, reverse connections to lines in X.28 mode only will work reliably to rotaries consisting of a single line.
Setting PAD French Language Service Signals
Extended dialog mode for PAD service signals is available in both the French and English languages with the PAD French Enhancement feature. The French language service signals are maintained in a table. When configured for the French language via PAD parameter 6, the PAD service signals map to this table, giving the appropriate French equivalent output. The internal table maintenance is based on the contents of the Annex-C/X.28 standard. Section 3.5/X.28 outlines parameter 6 and how it relates to extended mode dialog in multiple languages.
The French language service signals are maintained in a table. When set for the French language via PAD parameter 6, the PAD service signals map to the French language service signals and provide the appropriate French equivalent output.
In X.28 Mode
To set French language service signals in X.28 mode, use the following commands beginning in EXEC mode:
Step 1
Router> x28
Enters X.28 mode.
Step 2
* set 6:9
Sets the value of parameter 6 to 9 for French recognition.
Using an X.29 Profile
You can create an X.29 profile script that sets X.3 PAD parameters by using the x29 profile command. See the section "Creating an X.29 Profile Script" in the chapter "Configuring Protocol Translation and Virtual Asynchronous Devices" for more information about X.29 profiles.
To set French language service signals using an X.29 profile, use the following command in global configuration mode:
Router(config)# x29 profile profilename 6:9
Sets the value of parameter 6 to 9 (on a defined set of X.3 parameters) for French recognition in an X.29 profile.
Verifying PAD French Enhancement
To verify that PAD French enhancement has been configured, enter the parameter command in X.28 EXEC mode (for either X.28 or X.29 profiles):
* parameterPAR 1:1 2:1 3:16 4:0 5:1 6:9 7:2 8:0 9:1 10:0 11:4 12:1 13:0 14:0 15:0 16:12 17:2 18:0 19:0 20:0 21:0 22:0Remote Access to X.28 Mode
Several ways to access X.28 PAD mode on the router are described in the following sections:
Using an Asynchronous Line
If an asynchronous line is configured with the autocommand x28 command, the devices connected to the asynchronous line always get X.28 mode. Otherwise, an EXEC session is on the line and the x28 command can be issued to start X.28 mode.
To set up X.28 mode on the router, perform the following the steps:
Step 1
Router# configure terminalEnter configuration commands, one per line. End with CNTL/Z.Step 2
Router(config)# line 1 2Router(config-line)# autocommand x28
Using Incoming Telnet
An incoming Telnet connection originates from a TCP/IP network. This connection method is used for a two-step connection from an IP device to an X.25 device.
To set up an incoming Telnet connection on the router, perform the following the steps:
Step 1
Step 2
Router# configure terminalEnter configuration commands, one per line. End with CNTL/Z.Router(config)# line vty 0 4Router(config-line)# autocommand x28Router(config-line)# rotary 1Router(config-line)# exitRouter(config)#Step 3
Router(config)# ip alias aaa.bbb.ccc.ddd 3022In this example, 22 is the rotary number assigned. The field aaa.bbb.ccc.ddd is an additional IP address assigned to the router for X.28 PAD mode incoming calls.
Step 4
ip-host% telnet 172.19.90.18Trying 172.19.90.18...Connected to 172.19.90.18.Escape character is '^]'.User Access VerificationUsername: letmeinPassword: guessme*
Using Incoming X.25
An incoming X.25 connection originates from an X.25 network. This connection method is an unlikely scenario because most users likely are already connected to an X.25 host. However, this configuration is useful for circumventing security restrictions.
To set up incoming X.25 connection on the router, configure a range of virtual terminal lines with the autocommand x28 command and specify a rotary number with the rotary number command.
Router# configure terminalEnter configuration commands, one per line. End with CNTL/Z.Router(config)# line vty 0 4Router(config-line)# autocommand x28Router(config-line)# rotary 1The remote user can now access X.28 mode by initiating a connection to the X.21 address AAAAxx, where AAAA is the X.21 address of the router and xx is the specified rotary number.
Making X.25 PAD Calls over IP Networks
PAD calls can be made to destinations that are not reachable over physical X.25 interfaces, but instead over TCP tunnels. PAD calls originating from a router on an IP link can reach an X.25 device. This feature is also known as PAD over XOT (X.25 over TCP). The service pad to-xot command and service pad from-xot global configuration command enable the PAD over XOT feature. Figure 4 shows PAD calls originating from a router in an IP network reaching an X.25 device.
Figure 4 PAD Dialing In to an X.25 Host over an IP Network
To allow PAD connections over XOT on the router, use the following commands beginning in privileged EXEC mode:
Step 1
Enters global configuration mode.
Step 2
Router(config)# service pad [from-xot] [to-xot]
Specifies outgoing PAD calls over XOT or incoming XOT to PAD connections.
Step 3
Router(config)# x25 host name x121-address
or
Router(config)# x25 route x121-address xot x121-address
Depending on your application, specifies an X.121 address for the host name of the router or an X.25 route pointing out over XOT.1
1 The X.121 address of the x25 host command serves as a source address or sink address for PAD over XOT connections that do not have an interface. Protocol translation can also be used with incoming PAD calls over XOT, which is configured with the translate x25 command.
Configuring PAD Subaddressing
In situations where the X.121 calling address is not sufficient to identify the source of the call, you can append a specified value to the calling address using the PAD subaddressing feature. PAD subaddressing allows you to create unique X.121 calling addresses by including either a physical port number or a value specified for a line as a subaddress to the X.121 calling address.
PAD subaddressing enables an X.25 host application to uniquely identify the source of an X.121 call. For example, in some bank security alarm applications, the central alarm host identifies the physical location of the alarm units from subaddressing information contained in the Call Request packet.
Note
Before you can configure PAD subaddressing, you need to configure your router or access server to support X.25. For more information, refer to the Cisco IOS Wide-Area Networking Configuration Guide, Release 12.2.
To configure PAD subaddressing, use the following commands beginning in privileged EXEC mode:
Configuring X.29 Reselect
Cisco supports X.29 reselect, which is a standard Triple-X PAD function supported in later versions of the X.3, X.28, and X.29 specifications. X.29 reselect is used in conjunction with mnemonics and autoconnect/autocall to the "first host." X.29 reselect is for security checking and DNS, such as the X.25 naming/selection of destinations within a public or private network. The primary (first) destination host acts much like a RADIUS/TACACS server. At a minimum, both the PAD and the "first host" used in the topology need to support X.29 reselect. X.29 reselect is transparent to network elements or switches. No Cisco IOS commands need to be entered to enable X.29 reselect. It is enabled by default.
Using Mnemonic Addressing
Mnemonic addressing enables you to connect to a remote host by using its mnemonic address, not the X.121 address. As the number of hosts grows within an X.25 network, system administrators need to remember numerous 14-digit X.121 addresses to connect to multiple host applications. To ease the burden of this administrative overhead, asynchronous PAD users can now access hosts by using mnemonic (abbreviated) addressing.
When the user specifies the mnemonic address in the call X.28 command, the mnemonic gets translated to an X.121 address in the local PAD. The resulting call request contains both the X.121 calling and called addresses.
Note
Character Limitations
You can use the following formats to specify a mnemonic address:
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Mnemonic Format Options
This section provides examples of format options.
Example 1
Format
c <NUI, Facilities>-.<Mnemonic>*<call-user-data>
Description
This is the generalized format of the call command where you can specify NUI and facilities with -.mnemonics and an asterisk (*) before the call user data (CUD). The comma (,) separates individual facility specifications.
Example Syntax
Nsmith-.billing*xyz
In this example, the following facilities are specified:
smith = NUI and no facilitiesbilling = 31xx4085272478xyz = CUDExample 2
Format
c .<Mnemonic>*<call-user-data>
Description
No facilities, with CUD.
Example Syntax
c .billing*xyz
In this example, the following facility is specified:
billing = 31xx4085272478 with CUD of xyzExample 3
Format
c <Mnemonic>
Description
No dot, no facilities, no CUD.
Example syntax
billing
In this example, the following facility is specified:
billing = 31xx4085272478Example 4
Format
<Mnemonic>
Description
No dot, no facilities, no CUD.
Example Syntax
billing
In this example, the following facility is specified:
billing = 31xx4085272478Facility Codes
Table 3 lists the supported facility codes that can be specified in the Call Request packet. The X.121 address is a word with decimal digits.
PAD Examples
This section provides the following PAD connection and configuration examples:
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PAD EXEC User Interface Connection Examples
This section provides the following examples of making PAD connections using the pad command:
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PAD Mode Connection Examples
The following examples show two ways to make a call to a remote X.25 host over a serial line. The interface address of the remote host is 123456. In the first example, Router-A calls Router-B using the pad 123456 EXEC command. The second example shows Router-A calling Router-B using the call 123456 PAD signal command in X.28 mode. Both commands accomplish the same goal.
Router-A# pad 123456Trying 123456...OpenRouter-B> exit[Connection to 123456 closed by foreign host]Router-A# x28* call 123456COMRouter-B>The following examples show two ways to clear a connection with a remote X.25 host. The first example shows Router-A disconnecting from Router-B using the disconnect command in EXEC mode. The second example shows Router-B disconnecting from Router-A using the clr command in X.28 mode.
Router-A# pad 123456Trying 123456...OpenRouter-B> <Enter the escape sequence (for example, press Shift-Ctrl-^-x).>Router-A# disconnectClosing connection to 123456 [confirm]Router-A#Router-A# x28* call 123456COMRouter-B> <Press Ctrl-p>* clrCLR CONF*X.3 Parameter Customization Example
The following example shows how to change a local X.3 PAD parameter from a remote X.25 host using X.29 messages, which is a secure way to enable a remote host to gain control of local PAD. The local device is Router-A. The remote host is Router-B. The parameters listed in the ParamsIn field are incoming parameters, which are sent by the remote PAD. The parameters listed in the ParamsOut field are parameters sent by the local PAD.
Router-A# pad 123456Trying 123456...OpenRouter-B> x3 2:0Router-B>Router-A# show x25 padtty0, connection 1 to host 123456Total input: 12, control 3, bytes 35. Queued: 0 of 7 (0 bytes).Total output: 10, control 3, bytes 64.Flags: 1, State: 3, Last error: 1ParamsIn: 1:0, 2:0, 3:0, 4:0, 5:0, 6:0, 7:0,8:0, 9:0, 10:0, 11:0, 12:0, 13:0, 14:0, 15:0,16:0, 17:0, 18:0, 19:0, 20:0, 21:0, 22:0,ParamsOut: 1:1, 2:0, 3:2, 4:1, 5:1, 6:0, 7:21,8:0, 9:1, 10:0, 11:14, 12:1, 13:0, 14:0, 15:0,16:127, 17:21, 18:18, 19:0, 20:0, 21:0, 22:0,Router-A#Load an X.3 Profile Example
The following example modifies and loads an existing X.25 PAD parameter profile. It accesses the existing PAD profile ppp, changes its padding parameter (specified as 9) to a value of 2, and displays the new parameters using the par command in X.28 mode.
Router-A# configure terminalEnter configuration commands, one per line. End with CNTL/Z.Router-A(config)# x29 profile ppp 9:2Router-A(config)# endRouter-A#%SYS-5-CONFIG_I: Configured from console by consoleRouter-A# x28 profile ppp* parPAR 1:1 2:1 3:126 4:0 5:1 6:2 7:2 8:0 9:2 10:0 11:14 12:1 13:0 14:0 15:0 16:127 17:24 18:18 19:2 20:0 21:0 22:0
Note
Set PAD Parameters Example
The following example starts a PAD session:
Router> pad 123456789Trying 123456789...OpenRouter2>The following example shows how to reset the outgoing connection default for local echo mode on a router. The /set switch sets the X.3 parameters defined by parameter number and value, separated by a colon.
Router> resume 3 /set 2:1The following are examples of show x25 vc command output for PAD over Connection-Mode Network Service (CMNS), PAD to PAD over X.25, and PAD over XOT (X.25 over TCP) connections:
Router# show x25 vcSVC 1, State: D1, Interface: Ethernet0Started 00:01:48, last input 00:01:48, output 00:01:48Line: 0 con 0 Location: console Host: 2193330connected to 2193330 PAD <--> CMNS Ethernet0 00e0.b0e3.0d62Window size input: 2, output: 2Packet size input: 128, output: 128PS: 2 PR: 3 ACK: 3 Remote PR: 2 RCNT: 0 RNR: noP/D state timeouts: 0 timer (secs): 0data bytes 54/19 packets 2/3 Resets 0/0 RNRs 0/0 REJs 0/0 INTs 0/0SVC 1024, State: D1, Interface: Serial1Started 00:00:07, last input 00:00:26, output 00:00:26Line: 0 con 0 Location: console Host: 21944432191111 connected to 2194443 PAD <--> X25Window size input: 5, output: 5Packet size input: 128, output: 128PS: 0 PR: 0 ACK: 0 Remote PR: 0 RCNT: 0 RNR: noP/D state timeouts: 0 timer (secs): 0data bytes 0/0 packets 0/0 Resets 0/0 RNRs 0/0 REJs 0/0 INTs 0/0SVC 1, State: D1, Interface: [172.21.9.7,1998/172.21.9.11,11000]Started 00:06:48, last input 00:06:43, output 00:06:43Line: 0 con 0 Location: console Host: 219444001219111 connected to 219444001 PAD <--> XOT 172.21.9.7,1998Window size input: 2, output: 2Packet size input: 128, output: 128PS: 5 PR: 4 ACK: 4 Remote PR: 5 RCNT: 0 RNR: noP/D state timeouts: 0 timer (secs): 0data bytesThe following example shows output for the show x25 pad command:
Router# show x25 padtty0 (console), connection 1 to host 2194440Total input: 75, control 2, bytes 3168. Input Queued: 0 of 7 (0 bytes).Total output: 50, control 2, bytes 52. Output Queued: 0 of 5.Flags: 1, State: 3, Last error: 1ParamsIn: 1:0, 2:0, 3:0, 4:0, 5:0, 6:0, 7:0,8:0, 9:0, 10:0, 11:0, 12:0, 13:0, 14:0, 15:0,16:0, 17:0, 18:0, 19:0, 20:0, 21:0, 22:0,ParamsOut: 1:1, 2:0, 3:2, 4:1, 5:1, 6:0, 7:21,8:0, 9:0, 10:0, 11:14, 12:1, 13:0, 14:0, 15:0,16:127, 17:21, 18:18, 19:0, 20:0, 21:0, 22:0,tty18, Incoming PAD connectionTotal input: 2, control 2, bytes 54. Input Queued: 0 of 7 (0 bytes).Total output: 1, control 2, bytes 9. Output Queued: 0 of 5.Flags: 1, State: 3, Last error: 1ParamsIn: 1:1, 2:0, 3:2, 4:1, 5:0, 6:0, 7:21,8:0, 9:0, 10:0, 11:14, 12:0, 13:0, 14:0, 15:0,16:127, 17:21, 18:18, 19:0, 20:0, 21:0, 22:0,ParamsOut: 1:1, 2:1, 3:2, 4:1, 5:0, 6:0, 7:4,8:0, 9:0, 10:0, 11:14, 12:0, 13:0, 14:0, 15:0,16:127, 17:21, 18:18, 19:0, 20:0, 21:0, 22:0,Cisco Universal X.28 PAD Emulation Mode Examples
This section contains the following examples of making PAD connections using the x28 command:
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Set Parameters Using X.28 PAD Emulation Mode Example
The following example configures parameter 9 from 0 to 1, which adds a byte after the carriage return. This setting is performed from a local terminal using the set parameter-number:new-value PAD command signal.
Router# x28* parPAR 1:1 2:1 3:126 4:0 5:1 6:2 7:2 8:0 9:0 10:0 11:14 12:1 13:0 14:0 15:0 16:127 17:24 18:18 19:2 20:0 21:0 22:0* set 9:1* parPAR 1:1 2:1 3:126 4:0 5:1 6:2 7:2 8:0 9:1 10:0 11:14 12:1 13:0 14:0 15:0 16:127 17:24 18:18 19:2 20:0 21:0 22:0*NUI Data Relocation Example
The following example sends an authentication message to a remote X.25 host using the x28 nuicud command in Cisco X.28 mode followed by the Ncisc-123456 command. The network identifier is N. The network user password is cisc. The destination address of the remote device is 123456. The ASCII representation of the user password appears in the CUD field, not in the data packet.
Router-A# debug x25 eventX.25 special event debugging is onRouter-A# x28 nuicud* Ncisc-123456COMRouter-B>02:02:58: Serial1: X.25 O P1 Call (16) 8 lci 2002:02:58: From(3): 222 To(3): 12345602:02:58: Facilities: (0)02:02:58: Call User Data (8): 0x01000000xxxxxxxx (pad)02:02:58: Serial1: X.25 I P2 Call Confirm (5) 8 lci 2002:02:58: From(0): To(0):02:02:58: Facilities: (0)X.25 Reverse Charge Example
The following example shows how to use the x28 reverse command to make the charges for all outgoing calls made from the local router be reversed to the destination device. To reverse the charges for only one outgoing call, use the R-address command, which is the standard X.28 reverse charge facility command.
Router-A# x28 reverse* exitRouter-A# x28* R-123456COMX.25 Call Detail Display Example
Each time a call is made to a remote device, you can specify that detailed information be displayed about the call and the destination device by entering the x28 verbose command. The following example shows reverse charging configured and CUD represented as userdata:
Router# x28 verbose* R-111*userdataCalled DTE Address : 3001Facility Block : RCall User Data :userdataCOMSet PAD French Service Signals in X.28 Mode Example
The following example shows PAD French enhancement being set in X.28 EXEC mode:
Router # x28* set 6:9Set PAD French Service Signals with an X.29 Profile Example
The following example shows PAD French enhancement being set with an X.29 profile:
Router(config)# x29 profile Primary 6:9Get Help Example
The following example shows how to use the help command to get short descriptions of the available parameters:
* helpThe "help" PAD command signal consists of the following elements:<help PAD command signal> <help subject>where<help subject> is the identifier for the type ofexplanatory information requested* help breakBREAK Simulate async BREAKPAD XOT Examples
The following sections provide PAD over XOT configuration examples:
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Accept XOT to PAD Connections Example
The following example enables connections from XOT to a local PAD. Because XOT is a TCP connection, the connection is not tied to an X.25 interface. An X.25 address must be configured for the host name of the router that is accepting the call. In this case, the router answers and clears an incoming PAD call through address 1234.
Router(config)# service pad from-xotRouter(config)# x25 host Router-A 1234Accept XOT to Protocol Translation Example
The following example accepts an incoming PAD call over XOT to address 12345. The router then translates the call and makes a TCP connection to the device named puli.
Router(config)# service pad from-xotRouter(config)# translate x25 12345 tcp puliInitiate a PAD Call over an XOT Connection Example
The following example enables outgoing PAD to XOT connections from an asynchronous line or vty. A route pointing out over XOT must be configured on the routing table to make a PAD call. This route can also be used for switching.
Router(config)# service pad to-xotRouter(config)# x25 route 1111 xot 10.2.2.2.Address Substitution for PAD Calls Example
X25 synchronous or PAD devices attached to a router in a remote location may need to ensure that outgoing PAD calls use an assigned X.121 address for the calling (source) address or an assigned X.121 address for the called (destination) address.
Normally, the called address is sent by default in the outgoing PAD call. For the source address, the PAD applies the address for the originating interface (even if it is NULL) or the X25 host address (for example, XOT) as the source address of the call. To override the default behavior and substitute the original X.121 source/destination address in the outgoing PAD calls, use the x25 route command with the substitute-source and substitute-dest keyword options.
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Configuring Address Substitution
The following example performs address substitution for PAD calls over XOT:
Router(config)# x25 route ^1234 substitute-source 5678 xot 10.1.1.1or
Router(config)# x25 route ^1234 substitute-dest 5678 interface serial 1Verifying Address Substitution
To verify the source or destination address substitution on the outgoing PAD call, use the debug x25 event command and show x25 vc command.
For example, to substitute the destination address of 8888 to 5678 and replace the default source address of the outgoing PAD call to 1234, enter the following x25 route command:
Router(config)# x25 route 8888 substitute-source 1234 substitute-dest 5678 interface serial 1Placing a PAD call to destination 8888 will be substituted by 5678 and a source address of 1234:
Router# pad 8888Trying 8888...OpenThe following is output of the x25 debug event command:
Serial1: X.25 O R1 Call (13) 8 lci 1024From(4): 1234 To(4): 5678Facilities: (0)Call User Data (4): 0x01000000 (pad)Serial1: X.25 I R1 Call Confirm (5) 8 lci 1024From(0): To(0):Facilities: (0)The following is output from the show x25 vc command:
Router# show x25 vcSVC 1024, State: D1, Interface: Serial1Started 00:23:54, last input 00:00:13, output 00:00:13Line: 0 con 0 Location: console Host: 4561234 connected to 5678 PAD <--> X25Window size input: 2, output: 2Packet size input: 128, output: 128PS: 0 PR: 0 ACK: 0 Remote PR: 0 RCNT: 0 RNR: noP/D state timeouts: 0 timer (secs): 0data bytes 68/958 packets 16/27 Resets 0/0 RNRs 0/0 REJs 0/0 INTs 0/0PAD Subaddressing Examples
The following example shows how to configure subaddressing on virtual terminal lines 10 through 20 by appending the line number as a subaddress to the X.121 calling address:
Router(config)# line vty 10 20 Router(config-line)# x25 subaddress lineThe following example shows how to configure subaddressing on the first five TTY lines by appending the value 9 as a subaddress to the X.121 calling address of the X.28 connection originating on these lines:
Router(config-line)# line 1 5 Router(config-line)# x25 subaddress 9 Router(config-line)# autocommand x28You can use the output from the debug x25 event and the show line commands to display information about PAD subaddressing. Once you have configured PAD subaddressing, the output from both of these commands changes to reflect the additional subaddress information.
The following example shows debug x25 event output, where the X.25 address is 12345 and the subaddress for TTY line 3 is 09:
Router# debug x25 eventSerial1: X.25 O P1 Call (14) 8 lci 1024From(7): 1234509 To(4): 6789Facilities: (0)Call User Data (4): 0x01000000 (pad)Serial1: X.25 I P2 Call Confirm (5) 8 lci 1024From (0): to (0):Facilities: (0)PAD3: Call completedThe following example shows sample show line output for a router named enkidu, where line 18 has been configured for PAD subaddressing:
Router# show line 18Tty Typ Tx/Rx A Modem Roty AccO AccI Uses Noise Overruns18 VTY - - - - - 1 0 0/0Line 18, Location: "enkidu", Type: " "Length: 48 lines, Width: 80 columnsBaud rate: (TX/RX) is 9600/9600Status: Ready, Connected, Active, No Exit BannerCapabilities: Line usable as async interface, PAD Sub-addressing usedModem state: ReadyCCDE, CCENT, Cisco Eos, Cisco Lumin, Cisco Nexus, Cisco StadiumVision, Cisco TelePresence, Cisco WebEx, the Cisco logo, DCE, and Welcome to the Human Network are trademarks; Changing the Way We Work, Live, Play, and Learn and Cisco Store are service marks; and Access Registrar, Aironet, AsyncOS, Bringing the Meeting To You, Catalyst, CCDA, CCDP, CCIE, CCIP, CCNA, CCNP, CCSP, CCVP, Cisco, the Cisco Certified Internetwork Expert logo, Cisco IOS, Cisco Press, Cisco Systems, Cisco Systems Capital, the Cisco Systems logo, Cisco Unity, Collaboration Without Limitation, EtherFast, EtherSwitch, Event Center, Fast Step, Follow Me Browsing, FormShare, GigaDrive, HomeLink, Internet Quotient, IOS, iPhone, iQuick Study, IronPort, the IronPort logo, LightStream, Linksys, MediaTone, MeetingPlace, MeetingPlace Chime Sound, MGX, Networkers, Networking Academy, Network Registrar, PCNow, PIX, PowerPanels, ProConnect, ScriptShare, SenderBase, SMARTnet, Spectrum Expert, StackWise, The Fastest Way to Increase Your Internet Quotient, TransPath, WebEx, and the WebEx logo are registered trademarks of Cisco Systems, Inc. and/or its affiliates in the United States and certain other countries.
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