X.25 and LAPB Commands

The following are new commands:

Syntax Description

access-list-number	An integer from 1 to 199 that you select for the access list.
in	Restricts incoming connections between a particular access server and the addresses in the access list.

Defaults

No incoming access class is defined.

Command Modes

Line configuration

Command History

Release	Modification
10.3	This command was introduced.

Usage Guidelines

The access list number is used for both incoming Transmission Control Protocol (TCP) access and incoming packet assembler/disassembler (PAD) access.

In the case of TCP access, the access server uses the Internet Protocol (IP) access list defined with the access-list command.

For incoming PAD connections, the same numbered X.29 access list is referenced. If you only want to have access restrictions on one of the protocols, you can create an access list that permits all addresses for the other protocol.

Examples

The following example configures an incoming access class on virtual terminal line 4. For information on the line vty command see the Configuring the Route Processor for the Catalyst 8540 and Using Flash Memory Cards publication.

line vty 4
 access-class 4 in

Related Commands

Command	Description
access-list	Configures the access list mechanism for filtering frames by protocol type or vendor code.
x29 access-list	Limits access to the access server from certain X.25 hosts.

Syntax Description

enter	Causes the Cisco IOS software to send a special address translation packet that includes an enter emergency mode command to the Blacker Front End (BFE) if the emergency mode window is open. If the BFE is already in emergency mode, this command enables the sending of address translation information.
leave	Disables the sending of address translation information from the Cisco IOS software to the BFE when the BFE is in emergency mode.
type	Interface type.
number	Interface number.

Defaults

None

Command Modes

EXEC

Command History

Release	Modification
10.3	This command was introduced.

Examples

The following example enables an interface to participate in BFE emergency mode:

bfe enter serial 0

Related Commands

Command	Description
encapsulation x25	Specifies operation of a serial interface as an X.25 device.
x25 bfe-decision	Specifies how a router configured for x25 bfe-emergency decision will participate in emergency mode.
x25 bfe-emergency	Configures the circumstances under which the router participates in emergency mode.

Syntax Description

serial number	Local serial interface being used for X.25 service.
ethernet | fastethernet | tokenring | fddi number mac-address	Local CMNS interface (Ethernet, Fast Ethernet, Token Ring, or FDDI interface) and MAC address of the remote device; this information identifies a CMNS service.
vc-number	(Optional) SVC or PVC number, in the range 1 to 4095. If specified, the SVC is cleared or the PVC is reset. If not specified, the X.25 or CMNS service is restarted.
dlci number	(Optional) When combined with a serial interface number, it triggers a restart event for an Annex G logical X.25 VC.

Command Modes

Privileged EXEC

Command History

Release	Modification
11.2	This command was introduced. This command replaces the clear x25-vc command, which first appeared in Cisco IOS Release 8.3.
12.0(3)T	Annex G restart or clear options were added.

Usage Guidelines

This command form is used to disrupt service forcibly on an individual circuit or on all circuits using a specific X.25 service or CMNS service.

If this command is used without the vc-number value, a restart event is initiated, which implicitly clears all SVCs and resets all PVCs.

This command allows the option of restarting an Annex G connection per DLCI number, clearing all X.25 connections, or clearing a specific X.25 logical circuit number on that Annex G link.

Examples

The following example clears the SVC or resets the PVC specified:

clear x25 serial 0 1
 

The following example forces an X.25 restart, which implicitly clears all SVCs and resets all PVCs using the interface:

clear x25 serial 0
 

The following example restarts the specified CMNS service (if active), which implicitly clears all SVCs using the service:

clear x25 ethernet 0 0001.0002.0003
 

The following example clears the specified DLCI Annex G connection (40) from the specified interface:

clear x25 serial 1 40

Related Commands

Command	Description
clear xot	Clears an XOT SVC or resets an XOT PVC.
show x25 services	Displays information about X.25 services.
show x25 vc	Displays information about active X.25 virtual circuits.
frame-relay interface-dlci	Assigns a DLCI to a specified Frame Relay subinterface on the router or access server.
show x25 context	Displays details of an Annex G DLCI link.

Syntax Description

This command has no arguments or keywords.

Defaults

Each nonserial interface must be explicitly configured to use CMNS.

Command Modes

Interface configuration

Command History

Release	Modification
10.0	This command was introduced.

Usage Guidelines

After this command is processed on the LAN interfaces---Ethernet, Fiber Distributed Data Interface (FDDI), and Token Ring---all the X.25-related interface configuration commands are made available.

Examples

The following example enables CMNS on Ethernet interface 0:

interface ethernet 0
 cmns enable

Related Commands

Command	Description
x25 route	Creates an entry in the X.25 routing table (to be consulted for forwarding incoming calls and for placing outgoing PAD or protocol translation calls).

Syntax Description

dte	(Optional) Specifies operation as a data terminal equipment (DTE) device. This is the default LAPB mode.
dce	(Optional) Specifies operation as a data communications equipment (DCE) device.
multi	(Optional) Specifies use of multiple local-area network (LAN) protocols to be carried on the LAPB line.
protocol	(Optional) A single protocol to be carried on the LAPB line. A single protocol can be one of the following: apollo, appletalk, clns (ISO CLNS), decnet, ip, ipx (Novell IPX), vines, and xns. IP is the default protocol.

Defaults

The default serial encapsulation is High-Level Data Link Control (HDLC). You must explicitly configure a LAPB encapsulation method.

DTE operation is the default LAPB mode. IP is the default protocol.

Command Modes

Interface configuration

Command History

Release	Modification
10.0	This command was introduced.
10.3	The following keywords and argument were introduced: dte dce multi protocol

Usage Guidelines

LAPB encapsulations are appropriate only for private connections, where you have complete control over both ends of the link. Connections to X.25 networks should use an X.25 encapsulation configuration, which operates the X.25 Layer 3 protocol above a LAPB Layer 2.

One end of the link must be a logical DCE device, and the other end a logical DTE device. (This assignment is independent of the interface's hardware DTE or DCE identity.)

Both ends of the LAPB link must specify the same protocol encapsulation.

LAPB encapsulation is supported on serial lines configured for dial-on-demand routing (DDR). It can be configured on DDR synchronous serial and Integrated Services Digital Network (ISDN) interfaces and on DDR dialer rotary groups. It is not supported on asynchronous dialer interfaces.

A single-protocol LAPB encapsulation exchanges datagrams of the given protocol, each in a separate LAPB information frame. You must configure the interface with the protocol-specific parameters needed---for example, a link that carries IP traffic will have an IP address defined for the interface.

A multiprotocol LAPB encapsulation can exchange any or all of the protocols allowed for a LAPB interface. It exchanges datagrams, each in a separate LAPB information frame. Two bytes of protocol identification data precede the protocol data. You need to configure the interface with all the protocol-specific parameters needed for each protocol carried.

Beginning with Cisco IOS Release 11.0, multiprotocol LAPB encapsulation supports transparent bridging. This feature requires use of the encapsulation lapb multi command followed by the bridge-group command, which identifies the bridge group associated with multiprotocol LAPB encapsulation. This feature does not support use of the encapsulation lapb protocol command with a bridge keyword.

Beginning with Release 10.3, LAPB encapsulation supports the priority and custom queueing features.

Examples

The following example sets the operating mode as DTE and specifies that AppleTalk protocol traffic will be carried on the LAPB line:

interface serial 1
 encapsulation lapb dte appletalk

Related Commands

Command	Description
bridge-group	Assigns each network interface to a bridge group.

Syntax Description

dte	(Optional) Specifies operation as a DTE. This is the default X.25 mode.
dce	(Optional) Specifies operation as a DCE.
ddn	(Optional) Specifies DDN encapsulation on an interface using DDN X.25 Standard Service.
bfe	(Optional) Specifies BFE encapsulation on an interface attached to a BFE device.
ietf	(Optional) Specifies that the interface's datagram encapsulation defaults to use of the Internet Engineering Task Force (IETF) standard method, as defined by RFC 1356.

Defaults

The default serial encapsulation is HDLC. You must explicitly configure an X.25 encapsulation method.

DTE operation is the default X.25 mode. Cisco's traditional X.25 encapsulation method is the default.

Command Modes

Interface configuration

Command History

Release	Modification
10.0	This command was introduced.
10.3	The following keywords were added: dte dce ddn bfe ietf

Usage Guidelines

One end of an X.25 link must be a logical DCE device and the other end a logical DTE device. (This assignment is independent of the interface's hardware DTE or DCE identity.) Typically, when connecting to a public data network (PDN), the customer equipment acts as the DTE device and the PDN attachment acts as the DCE.

Cisco has long supported the encapsulation of a number of datagram protocols, using a standard means when available and a proprietary means when necessary. More recently the IETF adopted a standard, RFC 1356, for encapsulating most types of datagram traffic over X.25. X.25 interfaces use Cisco's traditional method unless explicitly configured for IETF operation; if the ietf keyword is specified, that standard is used unless Cisco's traditional method is explicitly configured. For details see the x25 map command.

Examples

The following example configures the interface for connection to a BFE device:

interface serial 0
 encapsulation x25 bfe

Related Commands

Command	Description
x25 map	Sets up the LAN protocols-to-remote host mapping.

Examples

The following example sets the interface outage period to 100 ms. The link remains connected for outages equal to or shorter than that period.

encapsulation lapb dte ip
lapb interface-outage 100

Syntax Description

window-size

Frame count. It can be a value from 1 to the modulo size minus 1 (the maximum is 7 if the modulo size is 8; it is 127 if the modulo size is 128).

Defaults

7 frames

Command Modes

Interface configuration

Command History

Release	Modification
10.0	This command was introduced.

Usage Guidelines

If the window size is changed while the protocol is up, the new value takes effect only when the protocol is reset. You will be informed that the new value will not take effect immediately.

When using the LAPB modulo 128 mode (extended mode), you must increase the window parameter k to send a larger number of frames before acknowledgment is required. This increase is the basis for the router's ability to achieve greater throughput on high-speed links that have a low error rate.

This configured value must match the value configured in the peer X.25 switch. Nonmatching values will cause repeated LAPB reject (REJ) frames.

Examples

The following example sets the LAPB window size (the k parameter) to 10 frames:

interface serial 0
 lapb modulo 
 lapb k 10

Related Commands

Command	Description
lapb modulo	Specifies the LAPB basic (modulo 8) or extended (modulo 128) protocol mode.

Syntax Description

modulus

Either 8 or 128. The value 8 specifies LAPB's basic mode; the value 128 specifies LAPB's extended mode.

Defaults

Modulo 8

Command Modes

Interface configuration

Command History

Release	Modification
10.0	This command was introduced.

Usage Guidelines

The modulo parameter determines which of LAPB's two modes is to be used. The modulo values derive from the fact that basic mode numbers information frames between 0 and 7, whereas extended mode numbers them between 0 and 127. Basic mode is widely available and is sufficient for most links. Extended mode is an optional LAPB feature that may achieve greater throughput on high-speed links that have a low error rate.

The LAPB operating mode may be set on X.25 links as well as LAPB links. The X.25 modulo is independent of the LAPB layer modulo. Both ends of a link must use the same LAPB mode.

When using modulo 128 mode, you must increase the window parameter k to send a larger number of frames before acknowledgment is required. This increase is the basis for the router's ability to achieve greater throughput on high-speed links that have a low error rate.

If the modulo value is changed while the protocol is up, the new value takes effect only when the protocol is reset. You will be informed that the new value will not take effect immediately.

Examples

The following example configures a high-speed X.25 link to use LAPB's extended mode:

interface serial 1
 encapsulation x25
 lapb modulo 128
 lapb k 40
 clock rate 2000000

Related Commands

Command	Description
lapb k	Specifies the maximum permissible number of outstanding frames, called the window size.

Syntax Description

bits	Maximum number of bits in multiples of eight. The minimum and maximum range is dynamically set. Use the question mark (?) to view the range.

Defaults

The largest (maximum) value available for the particular interface is the default. The Cisco IOS software dynamically calculates N1 whenever you change the maximum transmission unit (MTU), the L2/L3 modulo, or compression on a LAPB interface.

Command Modes

Interface configuration

Command History

Release	Modification
10.0	This command was introduced.

Usage Guidelines

The Cisco IOS software uses the following formula to determine the minimum N1 value:

(128 (default packet size) + LAPB overhead + X.25 overhead + 2 bytes of CRC) * 8

The Cisco IOS software uses the following formula to determine for the maximum N1 value:

(hardware MTU + LAPB overhead + X.25 overhead + 2 bytes of CRC) * 8

LAPB overhead is 2 bytes for modulo 8 and 3 bytes for modulo 128.

X.25 overhead is 3 bytes for modulo 8 and 4 bytes for modulo 128.

You need not set N1 to an exact value to support a particular X.25 data packet size. The N1 parameter prevents the processing of any huge frames that result from a "jabbering" interface, an unlikely event.

In addition, the various standards bodies specify that N1 be given in bits rather than bytes. While some equipment can be configured in bytes or will automatically adjust for some of the overhead information present, Cisco devices are configured using the true value, in bits, of N1.

You cannot set the N1 parameter to a value less than that required to support an X.25 data packet size of 128 bytes. All X.25 implementations must be able to support 128-byte data packets. Moreover, if you configure N1 to be less than 2104 bits, you receive a warning message that X.25 might have problems because some nondata packets can use up to 259 bytes.

You cannot set the N1 parameter to a value larger than the default unless the hardware MTU size is first increased.

The X.25 software accepts default packet sizes and calls that specify maximum packet sizes greater than those the LAPB layer supports, but negotiates the calls placed on the interface to the largest value that can be supported. For switched calls, the packet size negotiation takes place end-to-end through the router so the call will not have a maximum packet size that exceeds the capability of either of the two interfaces involved.

Caution The LAPB N1 parameter provides little benefit beyond the interface MTU and can easily cause link failures if misconfigured. Cisco recommends that this parameter be left at its default value.

Examples

The following example shows how to use the question mark (?) command to display the minimum and maximum N1 value. In this example, X.25 encapsulation has both the LAPB and X.25 modulo set to 8. Any violation of this N1 range results in an "Invalid input" error message.

router# interface serial 1
router(config)# lapb n1 ?
 
<1080-12056> LAPB N1 parameter (bits; multiple of 8)
 

The following example sets the N1 bits to 16440:

interface serial 0
 lapb n1 16440
 mtu 2048

Related Commands

Command	Description
mtu	Adjusts the maximum packet size or MTU size.

Syntax Description

tries

Transmission count. It can be a value from 1 to 255.

Defaults

20 transmissions

Command Modes

Interface configuration

Command History

Release	Modification
10.0	This command was introduced.

Examples

The following example sets the N2 tries to 50:

interface serial 0
 lapb n2 50

Syntax Description

milliseconds

Time in milliseconds. It can be a value from 1 to 64000.

Defaults

3000 ms

Command Modes

Interface configuration

Command History

Release	Modification
10.0	This command was introduced.

Usage Guidelines

The retransmission timer determines how long a transmitted frame can remain unacknowledged before the LAPB software polls for an acknowledgment. The design of the LAPB protocol specifies that a frame is presumed to be lost if it is not acknowledged within T1; a T1 value that is too small may result in duplicated control information, which can severely disrupt service.

Examples

The following example sets the T1 retransmission timer to 2000 ms:

interface serial 0
 lapb t1 2000

Syntax Description

seconds

Number of seconds between receipt of the last frame and transmission of the outgoing poll.

Defaults

0 seconds

Command Modes

Interface configuration

Command History

Release	Modification
10.0	This command was introduced.

Usage Guidelines

Examples

The following example will poll the other end of an active link if it has been 10 seconds since the last frame was received. If the far host has failed, the service will be declared down after n2 tries are timed out.

interface serial0
 encapsulation x25
 lapb t4 10

Related Commands

Command	Description
lapb n2	Specifies the maximum number of times a data frame can be sent (the LAPB N2 parameter).
lapb t1	Sets the retransmission timer period (the LAPB T1 parameter).

Syntax Description

type	(Optional) Interface type.
number	(Optional) Interface number.

Command Modes

EXEC

Command History

Release	Modification
10.0	This command was introduced.

Examples

The following is sample output from the show cmns command for an Ethernet interface:

Router# show cmns
 
Ethernet1 is administratively down, line protocol is down
  Hardware address is 0000.0c02.5f4c, (bia 0000.0c2.5f4c), state R1
    Modulo 8, idle 0, timer 0, nvc 1
    Window size: input 2, output 2, Packet size: input 128, output 128
    Timer: TH 0
    Channels: Incoming-only none, Two-way 1-4095, Outgoing-only none
    RESTARTs 0/0 CALLs 0+0/0+0/0+0 DIAGs 0/0
 

Related Commands

Command	Description
show interfaces serial	Displays information about a serial interface.

Syntax Description

interface number	(Optional) Specific logical X.25 VC interface.
dlci number	(Optional) Specific DLCI link.

Command Modes

EXEC

Command History

Release	Modification
12.0(3)T	This command was introduced.

Examples

The following is sample output from the show x25 context command:

Router# show x25 context
Serial1 DLCI 20 
PROFILE DCE, address <none>, state R1, modulo 8, timer 0
      Defaults: idle VC timeout 0
        input/output window sizes 2/2, packet sizes 128/128
      Timers: T10 60, T11 180, T12 60, T13 60
      Channels: Incoming-only none, Two-way 1-1024, Outgoing-only none
      RESTARTs 1/0 CALLs 0+0/0+0/0+0 DIAGs 0/0
  LAPB DCE, state CONNECT, modulo 8, k 7, N1 12056, N2 20
      T1 3000, T2 0, interface outage (partial T3) 0, T4 0
      VS 7, VR 6, tx NR 6, Remote VR 7, Retransmissions 0
      Queues: U/S frames 0, I frames 0, unack. 0, reTx 0
      IFRAMEs 111/118 RNRs 0/0 REJs 0/0 SABM/Es 14/1 FRMRs 0/0 DISCs 0/0
 

Related Commands

Command	Description
show x25 profile	Displays information about configured X.25 profiles.
show x25 vc	Displays information about active X.25 virtual circuits.
x25 profile	Configures an X.25 profile without allocating any hardware-specific information.

Syntax Description

local-cug	Locally significant CUG identifier.
number	Local CUG number (0 to 9999).
network-cug	Network translated CUG identifier.
number	Network CUG number (0 to 9999).

Command Modes

EXEC

Command History

Release	Modification
12.0(7)T	This command was introduced.

Usage Guidelines

You must designate either the local-cug or network-cug keyword with this command. Within these designations you can view all CUGs or a specific CUG defined by its local or network CUG identifier.

Examples

The following is sample output from the show x25 cug local-cug command, displaying information about all local CUGs on X.25 serial interface 0. Four CUGs have been subscribed to on serial interface 0, and they all have been configured for incoming and outgoing public access.

Router# show x25 cug local-cug
X.25 Serial0, 4 CUGs subscribed with incoming and outgoing public access
  local-cug 100 <-> network-cug 11 
  local-cug 200 <-> network-cug 22 
  local-cug 300 <-> network-cug 33 
  local-cug 5000 <-> network-cug 55, preferential
 

The following is sample output from the show x25 cug network-cug command specifically for network number 33 showing local CUG 300 is associated with it:

Router# show x25 cug network-cug 33
network-cug 33 <-> local-cug 300 
 

Related Commands

Command	Description
x25 subscribe cug-service	Enables and controls standard CUG behavior on an X.25 DCE interface.
x25 subscribe local-cug	Configures a DCE X.25 interface for a specific CUG subscription.

Syntax Description

name	(Optional) Displays the specific hunt group named.

Command Modes

EXEC

Command History

Release	Modification
12.0(3)T	This command was introduced.

Examples

The following is sample output from the show x25 hunt-group command:

Router# show x25 hunt-group 
  ID      Type      Target                  uses      status    traffic(out/in)
=================================================================================
HG1       rotary    Serial1                   2         last_used 17080 /10100
                    Serial2                   2         last_used 15640 /10100
                    xot 172.17.125.54         1         next       3120 /4424
                    xot 172.17.125.34         1         next         63 /88
 
HG2       vc-count  Serial0                   5         2 VC       3120 /4424
                    Serial3                   7         1 VC      15640 /10100
                    xot 172.17.125.45         3         3 VC        900 /500
=================================================================================
 

Status of an interface may be:

• next---Interface that will be used next for rotary distribution method.

• last used---Interface just used for rotary distribution method.

• unavailable---Interface is shutdown.

• full---All logical channels on the interface are in use.

• # VC---(vc-count only) Number of VCs currently in use on the interface.

• unoper---(can appear on rotary or vc-count types) All logical channels are unoperational.

Use the clear x25 command in EXEC mode to reset the "traffic," "# VC," and "uses" fields to zero.

Related Commands

Command	Description
clear x25	Restarts an X.25 or CMNS service, clears an SVC, or resets a PVC.
x25 hunt-group	Creates and maintains a hunt group.

Syntax Description

This command has no arguments or keywords.

Command Modes

EXEC

Command History

Release	Modification
10.0	This command was introduced.

Usage Guidelines

The show x25 map command shows information about the following:

• Configured maps (defined by the x25 map command)

• Maps implicitly defined by encapsulation PVCs (defined by the encapsulating version of the x25 pvc command)

• Dynamic maps (from the X.25 DDN or BFE operations)

• Temporary maps (from unconfigured CMNS endpoints)

Examples

The following is sample output from the show x25 map command:

Router# show x25 map
 
Serial0: X.121 1311001 <--> ip 172.20.170.1
  PERMANENT, BROADCAST, 2 VCS: 3 4*
Serial0: X.121 1311005 <--> appletalk 128.1
  PERMANENT
Serial1: X.121 2194441 cud hello <--> pad
  PERMANENT, windowsize 5 5, accept-reverse, idle 5
Serial1: X.121 1311005 <--> bridge
  PERMANENT, BROADCAST
Serial2: X.121 001003 <--> apollo 1.3,
         appletalk 1.3,
         ip 172.20.1.3,
         decnet 1.3,
         novell 1.0000.0c04.35df,
         vines 00000001:0003, 
         xns 1.0000.0c04.35df, 
         clns
  PERMANENT, NVC 8, 1 VC: 1024
 

Syntax Description

name	(Optional) Name of X.25 profile.

Command Modes

EXEC

Command History

Release	Modification
12.0(3)T	This command was introduced.

Examples

The following is sample output from the show x25 profile command, showing all profiles configured on the same interface. By not specifying the X.25 profile name, the output shows all configured profiles for that interface.

Router# show x25 profile
 
X.25 profile name:NetworkNodeA
  Number of references:2 
  In use by:
      Annex G:Serial1 DLCI 20
      Annex G:Serial1 DLCI 30
  PROFILE DCE, address <none>, state R/Inactive, modulo 128, timer 0
      Defaults:idle VC timeout 5
        input/output window sizes 2/2, packet sizes 128/128
      Timers:T10 60, T11 180, T12 60, T13 60
      Channels:Incoming-only none, Two-way 1-128, Outgoing-only none
  LAPB DCE, modulo 8, k 7, N1 default, N2 20
      T1 3000, T2 0, interface outage (partial T3) 0, T4 0
 
X.25 profile name:NetworkNodeB
  Number of references:1 
  In use by:
      Annex G:Serial1 DLCI 40
  PROFILE DTE, address 1111, state R/Inactive, modulo 8, timer 0
      Defaults:idle VC timeout 0
        input/output window sizes 2/2, packet sizes 128/128
      Timers:T20 180, T21 200, T22 180, T23 180
      Channels:Incoming-only none, Two-way 1-1024, Outgoing-only none
LAPB DTE, modulo 8, k 7, N1 default, N2 20
      T1 3000, T2 0, interface outage (partial T3) 0, T4 0
 

Related Commands

Command	Description
show x25 context	Displays details of an Annex G DLCI link.
show x25 vc	Displays information about active X.25 virtual circuits.
x25 profile	Configures an X.25 profile without allocating any hardware-specific information.

Syntax Description

This command has no arguments or keywords.

Command Modes

EXEC

Command History

Release	Modification
10.0	This command was introduced.

Examples

The following is sample output from the show x25 remote-red command:

Router# show x25 remote-red
 
Entry       REMOTE-RED     REMOTE-BLACK   INTERFACE
1           21.0.0.3       21.0.0.7       serial3
2           21.0.0.10      21.0.0.6       serial1
3           21.0.0.24      21.0.0.8       serial3
 

Table 43: show x25 remote-red Field Descriptions

Field	Description
Entry	Address mapping entry.
REMOTE-RED	Host IP address.
REMOTE-BLACK	IP address of the remote BFE device.
INTERFACE	Name of interface through which communication with the remote BFE device will take place.

Syntax Description

This command has no arguments or keywords.

Command Modes

EXEC

Command History

Release	Modification
10.0	This command was introduced.
12.0(5)T	The dns keyword was added.

Examples

The following example shows output from the show x25 route command:

Router# show x25 route
 
# Match                      Substitute               Route To
1 dest ^1311001$                                      Serial0, 0 uses
2 dest ^1311002$                                      xot 172.20.170.10
3 dest 444                                            xot dns \0
4 dest 555                                            xot dns \0
 

Related Commands

Command	Description
x25 route	Creates an entry in the X.25 routing table (to be consulted for forwarding incoming calls and for placing outgoing PAD or protocol translation calls).

Router# show x25 vc 1024
 
SVC 1024, State: D1, Interface: Serial0
 Started 0:00:31, last input 0:00:31, output 0:00:31
 Connects 170090 <-->
    compressedtcp 172.20.170.90
    ip 172.20.170.90
 Call PID multi, Data PID ietf
 Reverse charged
 Window size input: 2, output: 2
 Packet size input: 128, output: 128
 PS: 5 PR: 5 ACK: 4 Remote PR: 5 RCNT: 1 RNR: FALSE
 Window is closed
 P/D state timeouts: 0 Timer (secs): 0
  data bytes 505/505 packets 5/5 Resets 0/0 RNRs 0/0 REJs 0/0 INTs 0/0
 

Locally Switched X.25 Traffic Example

The following is sample output from the show x25 vc command used on a virtual circuit carrying locally switched X.25 traffic:

Router# show x25 vc
 
PVC 1, State: D1, Interface: Serial2
  Started 0:01:26, last input never, output never
  PVC <--> Serial1 PVC 1, connected
  Window size input: 2, output: 2
  Packet size input: 128, output: 128
  PS: 0 PR: 0 ACK: 0 Remote PR: 0 RCNT: 0 RNR: FALSE
  P/D state timeouts: 0 Timer (secs): 0 
  data bytes 0/0 packets 0/0 Resets 0/0 RNRs 0/0 REJs 0/0 INTs 0/0
 
SVC 5, State: D1, Interface: Serial2
  Started 0:00:16, last input 0:00:15, output 0:00:15
  Connects 170093 <--> 170090 from Serial1 VC 5
  Window size input: 2, output: 2
  Packet size input: 128, output: 128
  PS: 5 PR: 5 ACK: 4 Remote PR: 5 RCNT: 1 RNR: FALSE
  P/D state timeouts: 0 Timer (secs): 0 
  data bytes 505/505 packets 5/5 Resets 0/0 RNRs 0/0 REJs 0/0 INTs 0/0
 

Locally Switched X.25 Traffic Between PVCs and SVCs Example

The following is sample output from the show x25 vc command used on a virtual circuit carrying locally switched PVC to SVC X.25 traffic:

Router# show x25 vc
 
PVC 5,  State: D1,  Interface: Serial0
  Started 4d21h, last input 00:00:14, output 00:00:14
  Connects 101600 <--> 201700 from Serial2 VC 700
  D-bit permitted
  Window size input: 2, output: 2
  Packet size input: 128, output: 128
  PS: 5  PR: 5  ACK: 4  Remote PR: 5  RCNT: 1  RNR: no
  P/D state timeouts: 0  timer (secs): 0
  data bytes 1000/1000 packets 10/10 Resets 1/0 RNRs 0/0 REJs 0/0 INTs 0/0
 
SVC 700,  State: D1,  Interface: Serial2
  Started 00:00:16, last input 00:00:16, output 00:00:16
  Connects 101600 <--> 201700 from Serial0 PVC 5
  Window size input: 2, output: 2
  Packet size input: 128, output: 128
  PS: 5  PR: 5  ACK: 5  Remote PR: 4  RCNT: 0  RNR: no
  P/D state timeouts: 0  timer (secs): 103
  data bytes 500/500 packets 5/5 Resets 0/0 RNRs 0/0 REJs 0/0 INTs 0/0
 

Remotely Switched X.25 Traffic Example

The following is sample output from the show x25 vc command used on a virtual circuit carrying remotely switched X.25 traffic:

Router# show x25 vc
 
PVC 2, State: D1, Interface: Serial2
 Started 0:01:25, last input never, output never
 PVC <--> [172.20.165.92] Serial2/0 PVC 1 connected
 XOT between 171.20.165.91, 1998 and 172.20.165.92, 27801
 Window size input: 2, output: 2
 Packet size input: 128, output: 128
 PS: 0 PR: 0 ACK: 0 Remote PR: 0 RCNT: 0 RNR: FALSE
 P/D state timeouts: 0 Timer (secs): 0 Reassembly (bytes): 0
 Held Fragments/Packets: 0/0
 data bytes 0/0 packets 0/0 Resets 0/0 RNRs 0/0 REJs 0/0 INTs 0/0
 
SVC 6, State: D1, Interface: Serial2
 Started 0:00:04, last input 0:00:04, output 0:00:04
 Connects 170093 <--> 170090 from
 XOT between 172.20.165.91, 1998 and 172.20.165.92, 27896
 Window size input: 2, output: 2
 Packet size input: 128, output: 128
 PS: 5 PR: 5 ACK: 4 Remote PR: 5 RCNT: 1 RNR: FALSE
 P/D state timeouts: 0 Timer (secs): 0 Reassembly (bytes): 0
 Held Fragments/Packets: 0/0
 data bytes 505/505 packets 5/5 Resets 0/0 RNRs 0/0 REJs 0/0 INTs 0/0
 

Table 50: X.25 PVC States

Status Message	Description
awaiting PVC-SETUP reply	A remote PVC has initiated an XOT TCP connection and is waiting for a reply to the setup message.
can't support flow control values	The window sizes or packet sizes of the PVC cannot be supported by one of its two interfaces.
connected	The PVC is up.
dest. disconnected	The other end disconnected the PVC.
dest interface is not up	The target interface's X.25 service is down.
dest PVC config mismatch	The targeted PVC is already connected.
mismatched flow control values	The configured flow control values do not match.
no such dest. interface	The remote destination interface was reported to be in error by the remote router.
no such dest. PVC	The targeted PVC does not exist.
non-X.25 dest. interface	The target interface is not configured for X.25.
PVC/TCP connect timed out	A remote PVC XOT TCP connection attempt timed out.
PVC/TCP connection refused	A remote PVC XOT TCP connection was tried and refused.
PVC/TCP routing error	A remote PVC XOT TCP connection routing error was reported.
trying to connect via TCP	A remote PVC XOT TCP connection is established and is in the process of connecting.
waiting to connect	The PVC is waiting to be processed for connecting.

Syntax Description

This command has no arguments or keywords.

Defaults

Disabled

Command Modes

Interface configuration

Command History

Release	Modification
10.0	This command was introduced.

Usage Guidelines

This command causes the interface to accept reverse-charge calls by default. You can also configure this behavior for each peer with the x25 map interface configuration command.

Examples

The following example sets acceptance of reverse-charge calls:

interface serial 0
 x25 accept-reverse

Related Commands

Command	Description
x25 map	Sets up the LAN protocols-to-remote host mapping.

Syntax Description

x121-address

Variable-length X.121 address. It is assigned by the X.25 network service provider.

Defaults

Defense Data Network (DDN) and Blacker Front End (BFE) encapsulations have a default interface address generated from the interface IP address. For proper DDN or BFE operation, this generated X.121 address must not be changed. Standard X.25 encapsulations do not have a default.

Command Modes

Interface configuration

Command History

Release	Modification
10.0	This command was introduced.

Usage Guidelines

When you are connecting to a public data network (PDN), the PDN administrator will assign the X.121 address to be used. Other applications (for example, a private X.25 service), may assign arbitrary X.121 addresses as required by the network and service design. X.25 interfaces that engage in X.25 switching only do not need to assign an X.121 address.

Examples

The following example sets the X.121 address for the interface:

interface serial 0
 encapsulation x25
 x25 address 00000123005
 

The address must match that assigned by the X.25 network service provider.

Syntax Description

no	Prevents the router from participating in emergency mode and from sending address translation information to the BFE device.
yes	Allows the router to participate in emergency mode and to send address translation information to the BFE when the BFE enters emergency mode. This information is obtained from the table created by the x25 remote-red command.
ask	Configures the Cisco IOS software to prompt you to enter the bfe EXEC command.

Defaults

The router does not participate in emergency mode.

Command Modes

Interface configuration

Command History

Release	Modification
10.0	This command was introduced.

Examples

The following example configures serial interface 0 to require an EXEC command from you before it participates in emergency mode. The host IP address is 21.0.0.12, and the address of the remote BFE unit is 21.0.0.1. When the BFE enters emergency mode, the Cisco IOS software prompts you for the bfe enter EXEC command to direct the router to participate in emergency mode.

interface serial 0
 x25 bfe-emergency decision
 x25 remote-red 21.0.0.12 remote-black 21.0.0.1
 x25 bfe-decision ask

Related Commands

Command	Description
bfe	Allows the router to participate in emergency mode or to end participation in emergency mode when the interface is configured for x25 bfe-emergency decision and x25 bfe-decision ask.
x25 bfe-emergency	Configures the circumstances under which the router participates in emergency mode.
x25 remote-red	Sets up the table that lists the BFE nodes (host or gateways) to which the router will send packets.

Syntax Description

never	Prevents the router from sending address translation information to the Blacker Front End (BFE). If it does not receive address translation information, the BFE cannot open a new connection for which it does not know the address.
always	Allows the router to pass address translations to the BFE when it enters emergency mode and an address translation table has been created.
decision	Directs the router to wait until it receives a diagnostic packet from the BFE device indicating that the emergency mode window is open. The window is only open when a condition exists that allows the BFE to enter emergency mode. When the diagnostic packet is received, the participation in emergency mode depends on how the router is configured with the x25 bfe-decision command.

Defaults

No address translation information is sent to the BFE.

Command Modes

Interface configuration

Command History

Release	Modification
10.0	This command was introduced.

Examples

The following example configures serial interface 0 to require an EXEC command from you before it participates in emergency mode. The host IP address is 21.0.0.12, and the address of the remote BFE unit is 21.0.0.1. When the BFE enters emergency mode, the Cisco IOS software prompts you for the bfe enter EXEC command to direct the router to participate in emergency mode.

interface serial 0
 x25 bfe-emergency decision
 x25 remote-red 21.0.0.12 remote-black 21.0.0.1
 x25 bfe-decision ask
 

Related Commands

Command	Description
bfe	Allows the router to participate in emergency mode or to end participation in emergency mode when the interface is configured for x25 bfe-emergency decision and x25 bfe-decision ask.
x25 bfe-decision	Specifies how a router configured for x25 bfe-emergency decision will participate in emergency mode.

Syntax Description

protocol

Specifies the protocol to assume; may be ip or pad.

Defaults

None

Command Modes

Interface configuration

Command History

Release	Modification
10.0	This command was introduced.

Usage Guidelines

Examples

The following example establishes IP as the default protocol for X.25 calls:

interface serial 0
 x25 default ip
 

Related Commands

Command	Description
x25 map	Sets up the LAN protocols-to-remote host mapping.

Examples

The following example specifies a transit delay value in an X.25 configuration:

interface serial 0
 x25 facility transit-delay 24000
 

The following example sets an ROA name and then sends the list via the X.25 user facilities:

x25 roa green_list 23 35 36
interface serial 0
 x25 facility roa green_list
 

Related Commands

Command	Description
x25 suppress-called-address	Omits the destination address in outgoing calls.

Syntax Description

packets

Number of packets. A hold queue value of 0 allows an unlimited number of packets in the hold queue. This argument is optional for the no form of this command.

Defaults

10 packets

Command Modes

Interface configuration

Command History

Release	Modification
10.0	This command was introduced.

Usage Guidelines

If you set the queue-size argument to 0 when using the no x25 hold-queue command, there will be no hold queue limit. While this setting will prevent drops until the router runs out of memory, it is only rarely appropriate. A VC hold queue value is determined when it is created; changing this parameter will not affect the hold queue limits of the existing virtual circuits.

Examples

The following example sets the X.25 hold queue to hold 25 packets:

interface serial 0
 x25 hold-queue 25
 

Related Commands

Command	Description
ip mtu	Sets the MTU size of IP packets sent on an interface.
x25 ips	Sets the interface default maximum input packet size to match that of the network.
x25 ops	Sets the interface default maximum output packet size to match that of the network.

Syntax Description

minutes

Number of minutes to prevent calls from trying a previously failed destination. Incoming calls are still accepted.

Defaults

0 minutes

Command Modes

Interface configuration

Command History

Release	Modification
10.0	This command was introduced.

Usage Guidelines

Only Call Requests that the router originates are held down; routed X.25 Call Requests are not affected by this parameter.

Upon receiving a Clear Request for an outstanding Call Request, the X.25 support code immediately tries another Call Request if it has more traffic to send, and this action might cause overrun problems.

Examples

The following example sets this timer to 3 minutes:

interface serial 0
 x25 hold-vc-timer 3
 

Syntax Description

name	Host name.
x121-address	The X.121 address.
cud call-user-data	(Optional) Sets the Call User Data (CUD) field in the X.25 Call Request packet.

Defaults

No static host name-to-address mapping is defined.

Command Modes

Global configuration

Command History

Release	Modification
10.0	This command was introduced.

Usage Guidelines

This command permits you to map an X.121 address to an easily recognizable name. You can later use this host name instead of the X.121 address when you issue the translate command for X.25.

Examples

The following example specifies a static address mapping:

x25 host Willard 4085551212
 

The following example removes a static address mapping:

no x25 host Willard
 

The following example specifies static address mapping from the X.121 address 12345678 to the host name masala. It then uses the name masala in the translate command in place of the X.121 address when translating from the X.25 host to the PPP host with address 10.0.0.2.

x25 host masala 12345678
translate x25 masala ppp 10.0.0.2 routing
 

Related Commands

Command	Description
translate x25	When an X.25 connection request to a particular destination address is received, the Cisco router can automatically translate the request to another outgoing protocol connection type.

Syntax Description

name	Name you assign to the particular hunt group.
rotary	Each call steps to the next interface.
vc-count	Each call is placed on the interface with most available logical channels.

Command Modes

Global configuration

Command History

Release	Modification
12.0(3)T	This command was introduced.

Usage Guidelines

The following restriction applies:

Only one load-balancing distribution method can be selected for a hunt group, although one interface can participate in one or more hunt groups.

Examples

The following example shows the creation of hunt group "HG1" using the rotary distribution method, with X.25 configuration on serial interfaces 1 and 2 for that hunt group; as well as showing x25 configuration for the Ethernet interface (xot) with two specific target IP addresses (172.17.125.54 and 172.17.125.34). The example also shows the creation of hunt group "HG2" using the vc-count distribution method, with X.25 configuration on serial interfaces 0 and 3 for that hunt group; as well as showing X.25 configuration for the Ethernet interface (xot) with one specific target IP address (172.17.125.45).

Router(config)# x25 hunt-group HG1 rotary
Router(config-x25-huntgro)# interface serial 1
Router(config-x25-huntgro)# interface serial 2
Router(config-x25-huntgro)# xot 172.17.125.54
Router(config-x25-huntgro)# xot 172.17.125.34
Router(config-x25-huntgro)# exit
Router(config)# x25 hunt-group HG2 vc-count
Router(config-x25-huntgro)# interface serial 0
Router(config-x25-huntgro)# interface serial 3
Router(config-x25-huntgro)# xot 172.17.125.45

Related Commands

Command	Description
show x25 hunt-group	Displays X.25 hunt groups, detailed interface statistics, and distribution methods.

Syntax Description

minutes

Idle period in minutes.

Defaults

0 (the SVC is kept open indefinitely)

Command Modes

Interface configuration

Command History

Release	Modification
10.0	This command was introduced.

Usage Guidelines

Calls originated and terminated by the router are cleared; packet assembler/disassembler (PAD) and switched virtual circuits are not affected. To clear one or all virtual circuits at once, use the clear x25 privileged EXEC command.

Examples

The following example sets a 5-minute wait period before an idle circuit is cleared:

interface serial 2
 x25 idle 5
 

Related Commands

Command	Description
clear x25	Restarts an X.25 or CMNS service, to clear an SVC, or to reset a PVC.

Syntax Description

This command has no arguments or keywords.

Defaults

The router opens one VC for all types of service.

Command Modes

Interface configuration

Command History

Release	Modification
10.0	This command was introduced.

Usage Guidelines

This feature is useful only for DDN or BFE encapsulations, because only these methods have an IP precedence facility defined to allow the source and destination devices to both use the VC for traffic of the given IP priority.

Verify that your host does not send nonstandard data in the IP type of service (TOS) field because it can cause multiple wasteful virtual circuits to be created.

Four VCs may be opened based on IP precedence to encapsulate routine, priority, immediate, and all higher precedences.

The x25 map nvc limit or the default x25 nvc limit still applies.

Examples

The following example allows new IP encapsulation VCs based on the IP precedence:

interface serial 3
 x25 ip-precedence

Syntax Description

bytes

Byte count. It can be one of the following values: 16, 32, 64, 128, 256, 512, 1024, 2048, or 4096.

Defaults

128 bytes

Command Modes

Interface configuration

Command History

Release	Modification
10.0	This command was introduced.

Usage Guidelines

Note Set the x25 ips and x25 ops commands to the same value unless your network supports asymmetric input and output packet sizes.

Examples

The following example sets the default maximum packet sizes to 512:

interface serial 1
 x25 ips 512
 x25 ops 512

Related Commands

Command	Description
x25 facility	Forces facilities on a per-call basis for calls originated by the router (switched calls are not affected).
x25 ops	Sets the interface default maximum output packet size to match that of the network.

Syntax Description

circuit-number

VC number from 1 to 4095, or 0 if there is no incoming-only VC range.

Defaults

0

Command Modes

Interface configuration

Command History

Release	Modification
10.0	This command was introduced.

Usage Guidelines

This command is applicable only if you have the X.25 switch configured for an incoming-only VC range. Incoming is from the perspective of the X.25 DTE device. If you do not want any outgoing calls on your DTE device, disable the two-way range (set the values of x25 ltc and x25 htc to 0).

The following example sets a valid incoming-only VC range of 1 to 5, and sets the lowest two-way VC number:

interface serial 0
 x25 lic 1
 x25 hic 5
 x25 ltc 6

Related Commands

Command	Description
x25 hic	Sets the highest incoming-only VC number.

Syntax Description

This command has no arguments or keywords.

Defaults

Forcing packet-level restarts is the default and is necessary for networks that expect this behavior.

Command Modes

Interface configuration

Command History

Release	Modification
10.0	This command was introduced.

Examples

The following example disables the link-level restart:

interface serial 3
 no x25 linkrestart

Syntax Description

circuit-number

VC number from 1 to 4095, or 0 if there is no outgoing-only VC range.

Defaults

0

Command Modes

Interface configuration

Command History

Release	Modification
10.0	This command was introduced.

Usage Guidelines

This command is applicable only if you have the X.25 switch configured for an outgoing-only VC range. Outgoing is from the perspective of the X.25 DTE device. If you do not want any incoming calls from your DTE device, configure the values of x25 loc and x25 hoc and set the values of x25 ltc and x25 htc to 0.

Examples

The following example sets a valid outgoing-only virtual circuit range of 2000 to 2005:

interface serial 0
 x25 loc 2000
 x25 hoc 2005

Related Commands

Command	Description
x25 hoc	Sets the highest outgoing-only VC number.

Syntax Description

protocol	Protocol type, entered by keyword. Supported protocols are entered by keyword, as listed in Table 52. As many as nine protocol and address pairs can be specified in one command line.
address	Protocol address.
x121-address	X.121 address of the remote host.
option	(Optional) Additional functionality that can be specified for originated calls. Can be any of the options listed in Table 53.

Defaults

No LAN protocol-to-remote host mapping is set up.

Command Modes

Interface configuration

Command History

Release	Modification
10.0	This command was introduced.

Usage Guidelines

Because no defined protocol can dynamically determine LAN protocol-to-remote host mappings, you must enter all the information for each host with which the router may exchange X.25 encapsulation traffic.

When you configure multiprotocol maps, you can specify a maximum of nine protocol and address pairs in an x25 map command. However, you can specify a protocol only once. For example, you can specify the IP protocol and an IP address, but you cannot specify another IP address. If the compressedtcp and ip keywords are both specified, the same IP address must be used.

Bridging is supported only if you are using Cisco's traditional encapsulation method. For correct operation, bridging maps must specify the broadcast option.

Since most datagram routing protocols rely on broadcasts or multicasts to send routing information to their neighbors, the broadcast keyword is needed to run such routing protocols over X.25.

Encapsulation maps might also specify that traffic between the two hosts should be compressed, thus increasing the effective bandwidth between them at the expense of memory and computation time. Because each compression virtual circuit requires memory and computation resources, compression must be used with care and monitored to maintain acceptable resource usage and overall performance.

Note The OSPF broadcast mechanism assumes that IP class D addresses are never used for regular traffic over X.25.

You can modify the options of an x25 map command by restating the complete set of protocols and addresses specified for the map, followed by the desired options. To delete a map command, you must also specify the complete set of protocols and addresses; the options can be omitted when deleting a map.

Once defined, a map's protocols and addresses cannot be changed. This requirement exists because the Cisco IOS software cannot determine whether you want to add to, delete from, or modify an existing map's protocol and address specification, or simply mistyped the command. To change a map's protocol and address specification, you must delete it and create a new map.

A given protocol-address pair cannot be used in more than one map on the same interface.

Examples

The following example maps IP address 172.20.2.5 to X.121 address 000000010300. The broadcast keyword directs any broadcasts sent through this interface to the specified X.121 address.

interface serial 0
 x25 map ip 171.20.2.5 000000010300 broadcast
 

The following example specifies an ROA name to be used for originating connections:

x25 roa green_list 23 35 36
interface serial 0
 x25 map ip 172.20.170.26 10 roa green_list
 

The following example specifies a network user ID (NUID) facility to send on calls originated for the address map:

interface serial 0
 x25 map ip 172.20.174.32 2 nudata "Network User ID 35"
 

Strings can be quoted, but quotation marks are not required unless embedded blanks are present.

Related Commands

Command	Description
ip ospf network	Configures the OSPF network type to a type other than the default for a given medium.
show x25 map	Displays information about configured address maps.
x25 facility	Forces facilities on a per-call basis for calls originated by the router (switched calls are not affected).
x25 map bridge	Configures an Internet-to-X.121 address mapping for bridging over X.25.
x25 map compressedtcp	Maps compressed TCP traffic to an X.121 address.
x25 map pad	Configures an X.121 address mapping for PAD access over X.25.
x25 suppress-called-address	Omits the destination address in outgoing calls.
x25 route	Creates an entry in the X.25 routing table (to be consulted for forwarding incoming calls and for placing outgoing PAD or protocol translation calls).

Syntax Description

x121-address	The X.121 address.
broadcast	Required keyword for bridging over X.25.
option	(Optional) Services that can be added to this map (same options as the x25 map command). See Table 54 for more details.

Defaults

No bridging over X.25 is configured.

Command Modes

Interface configuration

Command History

Release	Modification
10.0	This command was introduced.

Usage Guidelines

The X.25 bridging software uses the same spanning-tree algorithm as the other bridging functions, but allows packets to be encapsulated in X.25 frames and transmitted across X.25 media. This command specifies IP-to-X.121 address mapping and maintains a table of both the Ethernet and X.121 addresses.

Examples

The following example configures transparent bridging over X.25 between two Cisco routers using a maximum of six virtual circuits:

interface serial 1
 x25 map bridge 000000010300 broadcast nvc 6

Related Commands

Command	Description
x25 map	Sets up the LAN protocols-to-remote host mapping.
x25 address	Sets the X.121 address of a particular network interface.

Syntax Description

ip-address	IP address.
protocol	(Optional) Protocol type, entered by keyword. Supported protocols are entered by keyword, as listed in Table 52. As many as nine protocol and address pairs can be specified in one command line.
address	(Optional) Protocol address.
x121-address	X.121 address.
option	(Optional) The same options as those for the x25 map command; see Table 53 earlier in this chapter.

Defaults

No mapping is configured.

Command Modes

Interface configuration

Command History

Release	Modification
10.0	This command was introduced.

Usage Guidelines

Note If you specify both ip and compressedtcp in the same x25 map compressedtcp command, they must both specify the same IP address.

The nvc map option cannot be used for TCP/IP header compression, because only one virtual circuit can carry compressed TCP/IP header traffic to a given host.

Examples

The following example establishes a map for TCP/IP header compression on serial interface 4:

interface serial 4
 ip tcp header-compression
 x25 map compressedtcp 172.20.2.5 000000010300

Related Commands

Command	Description
x25 map	Sets up the LAN protocols-to-remote host mapping.

Syntax Description

x121-address	X.121 address of the interface.
option	(Optional) Services that can be added to this map---the same options as the x25 map command (see Table 53 earlier in this chapter).

Defaults

No specific options are used for PAD access.

Command Modes

Interface configuration

Command History

Release	Modification
10.2	This command was introduced.

Usage Guidelines

Use a PAD map to configure optional X.25 facility use for PAD access. When used with the x25 pad-access interface configuration command, the x25 map pad command restricts incoming PAD access to those statically mapped hosts.

Examples

The following example configures an X.25 interface to restrict incoming PAD access to the single mapped host. This example requires that both incoming and outgoing PAD access use the network user identification (NUID) user authentication.

interface serial 1
 x25 pad-access
 x25 map pad 000000010300 nuid johndoe secret

Related Commands

Command	Description
x25 map	Sets up the LAN protocols-to-remote host mapping.
x25 pad-access	Causes the PAD software to accept PAD connections only from statically mapped X.25 hosts.

Syntax Description

modulus

Either 8 or 128. The value of the modulo parameter must agree with that of the device on the other end of the X.25 link.

Defaults

8

Command Modes

Interface configuration

Command History

Release	Modification
10.0	This command was introduced.

Usage Guidelines

X.25 supports flow control with a sliding window sequence count. The window counter restarts at zero upon reaching the upper limit, which is called the window modulus. Modulo 128 operation is also referred to as extended packet sequence numbering, which allows larger packet windows.

Examples

The following example sets the window modulus to 128:

interface serial 0
 x25 modulo 128

Related Commands

Command	Description
x25 facility	Forces facilities on a per-call basis for calls originated by the router (switched calls are not affected).
x25 win	Changes the default incoming window size to match that of the network.
x25 wout	Changes the default outgoing window size to match that of the network.

Syntax Description

count

Circuit count from 1 to 8. A maximum of eight virtual circuits can be configured for each protocol-host pair. Protocols that do not tolerate out-of-order delivery, such as encapsulated TCP/IP header compression, will use only one virtual circuit despite this value. Permitting more than one VC may help throughput on slow networks.

Defaults

1

Command Modes

Interface configuration

Command History

Release	Modification
10.0	This command was introduced.

Usage Guidelines

When the windows and output queues of all existing connections to a host are full, a new virtual circuit will be opened to the designated circuit count. If a new connection cannot be opened, the data is dropped.

Note The count value specified for thex25 nvc command affects the default value for the number of VCs. It does not affect the nvc option for any x25 map commands that are configured.

Examples

The following example sets the default maximum number of VCs that each map can have open simultaneously to 4:

interface serial 0
 x25 nvc 4

Syntax Description

bytes

Byte count that is one of the following: 16, 32, 64, 128, 256, 512, 1024, 2048, or 4096.

Defaults

128 bytes

Command Modes

Interface configuration

Command History

Release	Modification
10.0	This command was introduced.

Usage Guidelines

Note Set the x25 ips and x25 ops commands to the same value unless your network supports asymmetry between input and output packets.

Examples

The following example sets the default maximum packet sizes to 512:

interface serial 1
 x25 ips 512
 x25 ops 512

Related Commands

Command	Description
x25 ips	Sets the interface default maximum input packet size to match that of the network.