cc/td/doc/product/software
hometocprevnextglossaryfeedbacksearchhelp
PDF

Table of Contents

PAD Enhancements

Description

Platforms

Configuration Tasks

Configuration Examples

Command Reference

What to Do Next

PAD Enhancements

Description

Enhancements have been made to packet assembler/disassembler (PAD)-related functionality, which can be used in protocol translation services:

List of Terms

PAD--Packet assembler/disassembler.

PAD over XOT--The function of sending PAD calls to an X.25 host over an IP network.

XOT--The function of sending X.25 messages to an X.25 host over an IP network.

Platforms

The following platforms support the new PAD enhancements:

Configuration Tasks

This section provides configuration tasks for enabling PAD calls over XOT.

PAD over XOT enables PAD calls to destinations that are not reachable over physical X.25 interfaces, but over TCP tunnels. This function enables PAD calls originating from a router on an IP link to reach an X.25 device. PAD over XOT also enables incoming XOT connections from an IP link to be accepted as PAD or protocol translation connections on the local router. The service pad to-xot command and service pad from-xot global configuration commands enable this feature. Figure 16 shows PAD calls originating from a router in an IP network reaching a X.25 device.


Figure 16: PAD Dialing in to an X.25 Host over an IP Network



Incoming and outgoing PAD connections over XOT can be enabled on the router. To enable these connections, perform the following tasks beginning in global configuration mode:

Task Command
Step 1 Enter global configuration mode. configure terminal
Step 2 Specify outgoing PAD calls over XOT or incoming XOT to PAD connections. service pad [from-xot] [to-xot]
Step 3 Depending on your application, specify an X.121 address for the host name of the router or an X.25 route pointing out over XOT.1 x25 host name x121-address

or

x25 route x121-address xot x121-address


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.

Configuration Examples

This section provides the following PAD over XOT configuration examples:

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-A(config)# service pad from-xot
Router-A(config)# x25 host Router-A 1234

Accept 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 called puli.

Router-A(config)# service pad from-xot
Router-A(config)# translate x25 12345 tcp puli

Initiate a PAD Call over an XOT Connection Example

The following example enables outgoing PAD to XOT connections from an asynchronous line or virtual terminal line. 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-A(config)# service pad to-xot
Router-A(config)# x25 route 1111 xot 2.2.2.2.

Command Reference

This section documents modified commands. All other commands used with this feature are documented in the Cisco IOS Release 11.2 Wide-Area Networking Command Reference.

pad

To log on to a PAD, use the pad user EXEC command.

pad {x121-address | hostname} [/cud text] [/debug] [/profile name] [/reverse] [/use-map]
Syntax Description
x121-address Specifies the X.121 address of the X.25 host.
hostname Specifies the X.25 host name if the host-to-address mapping has been set with the X.25 host command.
/cud text (Optional) Includes the specified text in the Call User Data field of the outgoing Call Request Packet.
/debug (Optional) Displays the informational level of logging messages whenever the remote host changes an X.3 parameter setting or sends any other X.29 control packet.
/profile name (Optional) Sets X.3 PAD parameters for the name script. This is the same as issuing the x29 profile global configuration command when translating X.25.
/reverse (Optional) Causes reverse-charge calls to be accepted on a per-call (rather than a per-interface) basis.
/use-map (Optional) Applies x25 map pad command entry options (such as CUD and idle) and facilities (such as packet in, packet out, win in, and win out) to the outgoing PAD call. This function occurs only if a matching X.121 destination address exists in a x25 map pad command entry.
Command Mode

User EXEC

Usage Guidelines

This command first appeared in Cisco IOS Release 11.2.

The pad command supports one-word connections. You do not have to enter the pad command; just entering the address is enough to start the connection. A PAD can also be accessed and X.3 parameters configured with the x28 EXEC command, which uses the standard X.28 user interface.

You can have several PAD connections open at the same time and switch between them. You also 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, then open the new connection.

If the /use-map option is selected on the outgoing pad command, the x25 map pad command entries are searched for a matching X.121 destination address. If a match is found, the x25 map pad command entry options (such as CUD and idle) and facilities (such as packet in, packet out, win in, and win out) are applied to the outgoing PAD call.

To display information about packet transmission and X.3 PAD parameter settings, enter the show x25 pad command.

To exit a session, simply log off the remote system. Then, terminate the active session by entering the exit command.

Examples

The following example starts a PAD session: 

Router> pad 123456789
Trying 123456789...Open
Router>

You can also access a PAD using standard X.28 commands. The following example enters X.28 mode with the x28 EXEC command and configures a PAD with the set X.3 parameter command. The set command sets the idle time delay to 40 seconds.

Router# x28
* set 4:40

The following example uses the /use-map option to configure a larger window and packet size than the default specified on the interface, and it sets the VC idle time to 2 seconds. Notice that the map values are used rather than the interface default values.

Router-A(config-if)# x25 map pad 1234 cud gmcmilla windowsize 7 7 packetsize 1024 1024 idle 2 
Router-A(config-if)# end
Router-A#
%SYS-5-CONFIG_I: Configured from console by console. 
Router-A# pad 1234 /cud gmcmilla /use-map 
Trying 1234...Open
06:31:12: pad_find_ctxt: found a map
06:31:12: Serial1: X.25 O P1 Call (27) 8 lci 1024 06:31:12: From(4): 2222 To(4): 1234
06:31:12: Facilities: (6)
06:31:12:	Packet sizes: 1024 1024
06:31:12:	Window sizes: 7 7
06:31:12: Call User Data (12): 0x010000006573636861666665 (pad) 06:31:12: Serial1: X.25 I P2 Call Confirm (9) 8 lci 1024 06:31:12: From(4): 2222 To(4): 1234
06:31:12: Facilities: (0)
06:31:12: PAD0: Call completed
Related Command

translate x25

service pad

To enable all packet assembler/disassembler (PAD) commands and connections between PAD devices and access servers, use the service pad global configuration command. Use the no form of this command to not accept incoming and outgoing PAD connections.

service pad [from-xot] [to-xot]
no service pad [from-xot] [to-xot]
Syntax Description
from-xot (Optional) Accept XOT to PAD connections.
to-xot (Optional) Allow outgoing PAD calls over XOT.
Default

All PAD commands and associated connections are enabled.

Command Mode

Global configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 11.1.

By default, PAD over XOT connections are not allowed.

Examples

If the service pad command is disabled, the EXEC pad command and all PAD-related configurations, such as X.29, are unrecognized, as shown in the following example:

Router(config)# no service pad
Router(config)# x29 ?
% Unrecognized command
Router(config)# exit 
Router# pad ?
% Unrecognized command

If the service pad command is enabled, the EXEC pad command and access to an X.29 configuration is granted, as shown in the following example:

Router# config terminal
Enter configuration commands, one per line. End with CNTL/Z.
Router(config)# service pad
Router(config)# x29 ?
access-list       Define an X.29 access list
inviteclear-time  Wait for response to X.29 Invite Clear message
profile           Create an X.3 profile
Router# pad ?
WORD   X121 address or name of a remote system
Related Commands

x29 access-list
x29 profile

translate x25

When receiving an X.25 connection request to a particular destination address, the Cisco router can automatically translate the request to another outgoing protocol connection type. To set this up, use the translate global configuration command.

translate x25 incoming-address [in-options] {virtual-template number | protocol
outgoing-address [out-options]} [global-options]
Syntax Description
incoming-address X.25 and an X.121 address. The X.121 address must conform to specifications provided in the CCITT 1984 Red Book. This number generally consists of a portion that is administered by the PDN and a portion that is locally assigned. You must be sure that the numbers that you assign agree with the addresses assigned to you by the X.25 service provider. The X.121 addresses will generally be subaddresses of the X.121 address for the X.25 network interface. Typically, the interface address will be a 12-digit number. Any additional digits are interpreted as a subaddress. The PDN still routes these calls to the interface, and the Cisco IOS software itself is responsible for dealing with the extra digits appropriately. Do not use the same address on the interface and for translation.
in-options (Optional) Incoming connection request options. These arguments can have the following values:

· accept-reverse--Accepts reverse charged calls on an X.121 address even if the serial interface is not configured to accept reverse charged calls. This is an incoming option only.

· cud c-u-data--Sends the specified Call User Data (CUD) text (c-u-data) as part of an outgoing call request after the protocol identification bytes.

· idle minutes--Specifies the number of minutes the VC is idle. This option enables the protocol translation function to clear a switched virtual circuit (SVC) after a set period of inactivity, where minutes is the number of minutes in the period. Calls either originated or terminated are cleared. The maximum value of minutes is 255. The default value of minutes is zero.

· printer--Supports LAT and TCP printing over an X.25 network among multiple sites. Provides an "interlock mechanism" between the acceptance of an incoming X.25 connection and the opening of an outgoing LAT or TCP connection. The option causes the Cisco IOS software to delay the call confirmation of an incoming X.25 call request until the outgoing protocol connection (to TCP or LAT) has been successfully established. An unsuccessful outgoing connection attempt to the router results in the incoming X.25 connection being refused, rather than being confirmed and then cleared, which is the default behavior. Note that using this option will force the global option quiet to be applied to the translation.

· profile profile--Sets the X.3 PAD parameters as defined in the profile created by the x29 profile command.
virtual-template number Applies the specified virtual template in place of outgoing and global options. A virtual template is created with the interface virtual-template command.
protocol outgoing-address · autocommand--Enables you to specify a string for an outgoing connection. The string executes upon connection to a host. If you want to enable ARA on an outgoing connection, you need to specify the autocommand arap string.

The autocommand option is necessary for ARA, because ARA does not use addressing, and autocommand permits you to invoke the arap string.

If the string following autocommand has one or more spaces as part of the string, you must place quotation marks (" ") around the string. For example, if you specify autocommand tn3270 abracadabra, you must enclose the tn3270 abracadabra string in quotes.

The autocommand option applies only to outgoing connections.

You can issue any EXEC command and any switch or host name as an argument to the autocommand option.
out-options (Optional) Outgoing connection request options. These arguments can have the following values:
· use-map--Applies x25 map pad command entry options (such as CUD and idle) and facilities (such as packet in, packet out, win in, and win out) to the outgoing protocol translation call. This application occurs when the protocol translation function searches the X.25 map PAD entries and finds a matching X.121 destination address. The X.25 map facilities applied to the outgoing translation can be viewed with the show translation command throughout the duration of the translation session.
LAT translation options:

· node node-name--Connects to the specified node (node-name) that offers a service. By default, the connection is made to the highest-rated node that offers the service.

· port port-name--Destination LAT port name (port-name) in the format of the remote system. This parameter is usually ignored in most timesharing systems but is used by terminal servers that offer reverse-LAT services.

Telnet TCP translation options:

· port number--For incoming connections, number of the port to match. The default is port 23 (any port). For outgoing connections, number of the port to use. The default is port 23 (Telnet).

SLIP and PPP translation options:

· ip-pool--Obtain an IP address from a DHCP proxy client or a local pool. If the scope-name option is not specified, the address is obtained from a DHCP proxy client. If the scope-name option is specified, the IP address is obtained from the specified local pool.

· scope-name--Specific local scope name from which to obtain an IP address. This option can specify a range of IP addresses.

· header-compression [passive]--Implements header compression on IP packets only. The option passive for SLIP connections permits compression on outgoing packets only if incoming TCP packets on the same virtual asynchronous interface are compressed. The default (without the passive option) permits compression on all traffic.

· routing--Permits routing updates between connections. This option is required if the destination device is not on a subnet connected to one of the interfaces on the router.

· mtu bytes--Permits you to change the maximum transmission unit (MTU) of packets that the virtual asynchronous interface supports. The default MTU is 1500 bytes on a virtual asynchronous interface. The acceptable range is 64 to 1,000,000 bytes.

PPP translation options:

· keepalive number-of-seconds--Permits you to specify the interval at which keepalive packets are sent on SLIP and PPP virtual asynchronous interfaces. By default, keepalive packets are enabled and are sent every 10 seconds. To shut off keepalive packets, use a value of 0. The active keepalive interval is 1 to 32767 seconds. When you do not change from the default of 10, the keepalive interval does not appear in the show running-config or show translate command output.

· authentication {chap | pap}--Use CHAP or PAP authentication for PPP on virtual asynchronous interfaces. If you specify both options, order is significant; the system will try to use the first authentication type, then the second. Refer to the "Terminal Lines and Modem Support" chapter in the Cisco IOS Release 11.2 Access Services Configuration Guide for more information about enabling authentication on virtual asynchronous interfaces.

· ppp use-tacacs--Enables TACACS authentication for CHAP or PAP on virtual asynchronous interfaces (for PPP only; TACACS authentication is not supported for SLIP).

· ipx loopback number--Specifies the loopback interface to be created and permits clients running IPX-PPP over X.25 to connect through virtual terminal (VTY) lines on the router. A loopback interface must have been created and configured with a Novell IPX network number before IPX-PPP can work on the VTY line. The VTY line is assigned to the loopback interface. For more information about configuring IPX on VTY lines, refer to the section "Enable IPX-PPP on Virtual Asynchronous Interfaces" in the chapter "Configuring SLIP and PPP" of the Cisco IOS Release 11.2 Access Services Configuration Guide.
global-options (Optional) Translation options that can be used by any connection type. It can be one or more of the following:

· access-class number--Allows the incoming call to be used by source hosts that match the access list parameters. The argument number is the number (integer) previously assigned to an access list. The standard access list is 1 to 99.

· max-users number--Limits the number of simultaneous users of the translation to number (an integer you specify).

· local--Prevents Telnet protocol negotiations to from being translated.

· login--Requires that the user log in before the outgoing connection is made. This type of login is specified on the VTY lines with the login command.

· rotor--Provides a basic load sharing of the IP destinations.

· quiet--Suppresses printing of user-information messages.

· swap--Allows X.3 parameters to be set on the router by the host originating the X.25 call or by an X.29 profile. This configuration enables incoming and outgoing X.25 connections to be swapped so that the device is treated like a PAD when it accepts a call. By default, the router functions like a PAD for calls that it initiates, and like an X.25 host for calls it accepts. The swap keyword allows connections from an X.25 host that wants to connect to the router, and then treats it like a PAD. For X.25-to-TCP translations only.

· pvc number {[interface serial number] [packetsize in-size out-size] [windowsize in-size out-size]}--Specifies that the incoming or outgoing connection is actually a permanent virtual circuit (PVC). Only one session is allowed per PVC, where:

number --Specifies the virtual-circuit channel number of the incoming connection, which must be less than the virtual circuits assigned to the switched virtual circuits (SVC).

interface serial number--Specifies a PVC interface on which to set up the PVC connection.

packetsize in-size out-size--Specifies the input packet size (in-size) and output packet size (out-size) for the PVC. Following are valid packet size values:

16, 32, 64, 128, 256, 512 1024, 2048, or 4096

windowsize in-size out-size--Specifies the packet count for input windows (in-size) and output windows (out-size) for the outgoing translation. Values of in-size and out-size range 1 to 127 and must not be greater than the value set for the x25 modulo command. You must specify the same value for in-size and out-size.
Default

No default translation parameters

Command Mode

Global configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 10.0.

Table 13 provides a visual aid for understanding how to use the translate x25 command. In the table, follow the steps horizontally (from left to right). As you travel from step to step, you can choose from a vertical list of options at each step. As the table illustrates, you define the protocol translation connections by choosing a protocol keyword and supplying the appropriate address or service name. The protocol connection information is followed by optional features for that connection, as appropriate. The global options, in general, apply to all the connection types, but there are exceptions. The swap keyword, for example, is for X.25 to TCP translations only. See the examples for more explanations on how to enter this command.


Table 13: Sequence of Steps for Translating a Protocol
Incoming Protocol

Step 1

Incoming Options

Step 2

Outgoing Protocol

Step 3

Outgoing Options

Step 4

Global Options

Step 5

translate protocol incoming-address [in-options] protocol outgoing-address [out-options] [global-options]
idle minutes use-map
x25 x121-address cud c-u-data lat service-name node node-name access-class number
profile profile port port-name max-users number
accept-reverse tcp ip-address port number local
printer host-name name login
idle minutes multibyte-iac quiet
slip ip-address ip-pool [scope-name name] swap
headercompression [passive] pvc [number | interface serial-number] packetsize in-size out-size windowsize in-size out-size
routing
keepalive number-of-seconds
mtu bytes
ppp ip-address ip-pool
headercompression [passive]
routing
keepalive number-of-seconds
mtu bytes
authentication {pap | chap}
ppp use-tacacs
ipx loopback number
autocommand [arap | exec-string]

virtual-template
Examples

The following example illustrates a simple X.25-to-TCP translate x25 command. Packets coming in X.25 address 652365123 arrive via PVC 1 and are translated to TCP packets and transmitted out IP address 172.16.1.1.

translate x25 652365123 pvc 1 tcp 172.16.1.1
!         incoming       option outgoing

The following example illustrates a more complex configuration that calls an X.29 profile and swaps the default PAD operation of the router to that of an X.25 host. The name of the profile is fullpackets.

x29 profile fullpackets 2:0 3:0 4:100 7:21
translate x25 217536124 profile fullpackets tcp rubble port 4006 swap
!         incoming      option              outgoing   option    global

The following example illustrates the use of the X.25 incoming protocol option printer for an incoming X.25 connection.

translate x25 55555  printer tcp 172.16.1.1
!         incoming   option  outgoing

The following example translates X.25 packets to PPP. It enables routing updates between the two connections. 

translate x25 12345678 ppp 10.0.0.2 routing
!         incoming     outgoing    option

The following example permits clients running ARA to connect through the devices' VTY lines to an AppleTalk network. 

appletalk routing
translate x25 12345678 autocommand arap
!         incoming     outgoing 
  arap enable
  arap dedicated
  arap timelimit 45
  arap warningtime 5
  arap noguest
  arap require-manual-password
  arap net-access-list 614

The following example specifies IP pooling from a DHCP server named ludicrous. It then specifies that incoming TCP traffic be translated to SLIP. The DHCP server will dynamically assign IP addresses on the outgoing sessions.

ip address-pool dhcp-proxy-client
ip dhcp-server ludicrous
translate x25 5467835 ppp ip-pool scope-name ludicrous

The following example specifies a local IP pool named scandal with IP addresses ranging from 172.18.10.10 to 172.18.10.110. It then specifies that incoming X.25 traffic be translated to PPP. The local IP pool scandal will be used to dynamically assign IP addresses on the outgoing sessions.

ip-pool scandal 172.18.10.10 172.18.10.110
translate x25 1234567 ppp ip-pool scope-name scandal

X.25 calls are cleared if they are idle for the configured time, as shown in the following example:

translate x25 1234 idle 2 lat shazam
Related Commands

show translate
translate lat
translate tcp
x29 access-list
x29 profile

What to Do Next

Refer to the "Configuring X.25 and LAPB" chapter in the Cisco IOS Release 11.2 Wide-Area Networking Configuration Guide for more information about configuring X.25.


hometocprevnextglossaryfeedbacksearchhelp
Copyright 1989-1997 © Cisco Systems Inc.