- Introduction
- A through C
- D through E
- fdl through frame-relay lapf n200
- frame-relay lapf n201 through fr-atm connect dlci
- H through L
- M through R
- sequencing through show rgf statistics
- show smds addresses through waas export
- x25 accept-reverse through x25 pvc (XOT)
- x25 pvc rbp local through xot access-group
- x25 accept-reverse
- x25 address
- x25 address (line)
- x25 alias
- x25 bfe-decision
- x25 bfe-emergency
- x25 call-record
- x25 default
- x25 facility
- x25 fail-over
- x25 hic
- x25 hoc
- x25 hold-queue
- x25 hold-vc-timer
- x25 host
- x25 htc
- x25 hunt-group
- x25 idle
- x25 ip-precedence
- x25 ips
- x25 lic
- x25 linkrestart
- x25 loc
- x25 ltc
- x25 map
- x25 map bridge
- x25 map cmns
- x25 map compressedtcp
- x25 map pad
- x25 map rbp local
- x25 map rbp remote
- x25 modulo
- x25 nvc
- x25 ops
- x25 pad-access
- x25 profile
- x25 pvc (encapsulation)
- x25 pvc (switched PVC to SVC)
- x25 pvc (switched)
- x25 pvc (XOT)
x25 accept-reverse
To configure the Cisco IOS software to accept all reverse-charge calls, use the x25 accept-reverse command in interface or X.25 profile configuration mode. To disable this facility, use the no form of this command.
x25 accept-reverse
no x25 accept-reverse
Syntax Description
This command has no arguments or keywords.
Defaults
Disabled
Command Modes
Interface configuration
X.25 profile configuration
Command History
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
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x25 map |
Sets up the LAN protocols-to-remote host mapping. |
x25 address
To set the X.121 address of a particular network interface, use the x25 address command in interface or X.25 profile configuration mode.
x25 address x121-address
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
X.25 profile configuration
Command History
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.
x25 address (line)
To assign an X.121 address to a TTY line, use the x25 address command in line configuration mode. To remove the assigned address, use the no form of this command.
x25 address x121-address
no x25 address x121-address
Syntax Description
x121-address |
X.121 address. The address must be a numerical string no longer than 20 digits. |
Command Default
No X.121 address is defined.
Command Modes
Line configuration
Command History
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|---|---|
12.3(11)YN |
This command was introduced. |
12.4(4)T |
This command was integrated into Cisco IOS Release 12.4(4)T. |
Usage Guidelines
Each X.121 address can be associated with only one line.
This command cannot configure VTY lines.
Examples
The following example assigns the X.121 address of 12345 to the TTY line:
x25 address 12345
Related Commands
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x25 address |
Sets the X.121 address of a particular network interface. |
x25 alias
To configure an interface alias address that will allow this interface to accept calls with other destination addresses, use the x25 alias command in interface or X.25 profile configuration mode.
x25 alias {destination-pattern | x121-address-pattern} [cud cud-pattern]
Syntax Description
Defaults
No alias is configured.
Command Modes
Interface configuration
X.25 profile configuration
Command History
Usage Guidelines
Encapsulation, packet assembler/disassembler (PAD), and Qualified Logical Link Control (QLLC) calls are normally accepted when the destination address is that of the interface (or the zero-length address). Those calls will also be accepted when the destination address matches a configured alias.
Examples
An X.25 call may be addressed to the receiving interface; calls addressed to the receiving interface are eligible for acceptance as a datagram encapsulation, PAD or QLLC connection, and may not be routed. In the following example, serial interface 0 is configured with a native address of 0000123 and a destination alias for any address that starts with 1111123. That is, serial interface 0 can accept its own calls and calls for any destination that starts with 1111123.
interface serial 0
encapsulation x25
x25 address 0000123
x25 alias ^1111123.*
x25 bfe-decision
Note 
Effective with Cisco IOS Release 12.2, the x25 bfe-decision command is not available in Cisco IOS Software.
To specify how a router configured for x25 bfe-emergency decision will participate in emergency mode, use the x25 bfe-decision command in interface configuration mode.
x25 bfe-decision {no | yes | ask}
Syntax Description
Command Default
The router does not participate in emergency mode.
Command Modes
Interface configuration (config-if)
Command History
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10.0 |
This command was introduced. |
12.2 |
This command became unsupported. |
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
x25 bfe-emergency
Note Effective with Cisco IOS Release 12.2, the x25 bfe-emergency command is not available in Cisco IOS Software.
To configure the circumstances under which the router participates in emergency mode, use the x25 bfe-emergency command in interface configuration mode.
x25 bfe-emergency {never | always | decision}
Syntax Description
Defaults
No address translation information is sent to the BFE.
Command Modes
Interface configuration (config-if)
Command History
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10.0 |
This command was introduced. |
12.2 |
This command became unsupported. |
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
x25 call-record
To enable a record to be made of outgoing, incoming, and switched calls on the router, use the x25 call-record command in global configuration mode. To disable such record-making, use the no form of this command.
x25 call-record
no x25 call-record
Syntax Description
This command has no arguments or keywords.
Command Default
No call record is generated.
Command Modes
Global configuration (config)
Command History
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12.4(15)T |
This command was introduced. |
Usage Guidelines
Cisco recommends that you configure the router to use Syslog Facility to send the generated call records automatically to a remote syslog server for immediate storage and subsequent retrieval. You'll find instructions on how to do that in the X.25 Call Record document.
Examples
The following example enables generation of records about calls arriving, leaving, or being switched at the router:
x25 call-record
Following are two records generated by one such call, which arrived on an intermediate router's serial interface and departed through XOT, being routed over a hunt group:
Record of the Incoming VC: Example
Jun 7 10:42:00.131: %X25-5-CALL_RECORD:
Start=10:41:54.187 UTC Wed Jun 7 2006, End=10:42:00.131 UTC Wed Jun 7 2006,
Host=R3845-86-34, Client=Switch,
Call-direction=incoming, Calling-addr=33030, Called-addr=3500,
Interface=Serial0/3/1, Logical-channel=1024,
Facilities=win-in 2, win-out 2, pkt-in 128, pkt-out 128 tput-in 0, tput-out 0, fast-select
no, reverse-charging no,
Bytes sent/rcvd=52/55, Packets sent/rcvd=3/3,
Clear cause=0, Diag code=0
Record of the Outgoing VC: Example
Jun 7 10:42:00.131: %X25-5-CALL_RECORD:
Start=10:41:54.187 UTC Wed Jun 7 2006, End=10:42:00.131 UTC Wed Jun 7 2006, Host=R3845-86-34, Client=Switch, Huntgroup=HG4,
Call-direction=outgoing, Calling-addr=33030, Called-addr=3500,
Interface=XOT (local: 10.2.86.34:23686 remote: 10.2.86.35:1998), Logical-channel=1, Facilities=win-in 2, win-out 2, pkt-in 128, pkt-out 128 tput-in 0, tput-out 0, fast-select no, reverse-charging no,
Bytes sent/rcvd=55/52, Packets sent/rcvd=3/3,
Clear cause=0, Diag code=0
Related Commands
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logging host |
Enables logging to a remote syslog server. |
x25 default
To set a default protocol that Cisco IOS software will assume applies to incoming calls with unknown or missing protocol identifier in the call user data (CUD), use the x25 default command in interface configuration mode or X.25 profile configuration mode. To remove the default protocol specified, use the no form of this command.
x25 default protocol
no x25 default protocol
Syntax Description
protocol |
Specifies the protocol to assume; may be ip or pad. |
Defaults
No default protocol is specified.
Command Modes
Interface configuration
X.25 profile configuration
Command History
Usage Guidelines
This command specifies the protocol assumed by the Cisco IOS software for incoming calls with unknown or missing protocol identifier in the call user data (CUD). If you do not use the x25 default interface configuration command, the software clears any incoming calls with unrecognized CUD.
Examples
The following example establishes IP as the default protocol for X.25 calls:
interface serial 0
x25 default ip
Related Commands
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x25 map |
Sets up the LAN protocols-to-remote host mapping. |
x25 facility
To force facilities on a per-call basis for calls originated by the router (switched calls are not affected), use the x25 facility command in interface or X.25 profile configuration mode. To disable a facility, use the no form of this command.
x25 facility option
no x25 facility option
Syntax Description
option |
Set of user facilities options. See Table 107 for a list of supported facilities and their values. |
Defaults
No facility is sent.
Command Modes
Interface configuration
X.25 profile configuration
Command History
Usage Guidelines
Table 107 lists the set of x25 facility command user facilities options.
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
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x25 suppress-called-address |
Omits the destination address in outgoing calls. |
x25 fail-over
To configure a secondary interface and set the number of seconds for which a primary interface must be up before the secondary interface resets, use the x25 fail-over command in the appropriate configuration mode. To prevent the secondary interface from resetting, use the no form of this command.
x25 fail-over seconds interface type number [dlci | mac-address]
no x25 fail-over seconds interface type number [dlci | mac-address]
Syntax Description
Defaults
No default behavior or values
Command Modes
Interface configuration
X.25 profile configuration
Command History
Usage Guidelines
The x25 fail-over command can be configured on a primary X.25 interface or an X.25 profile only.
Examples
In the following example, X.25 failover is configured on a network that is also configured for Annex G. If data-link connection identifier (DLCI) 13 or DLCI 14 on serial interface 1/0 goes down, dialer interface 1 will serve as the secondary interface. After DLCI 13 or 14 comes back up and remains up for 20 seconds, dialer interface 1 will reset, sending all calls back to the primary interface.
interface serial1/0
encapsulation frame-relay
frame-relay interface-dlci 13
x25-profile frame1
exit
frame-relay interface-dlci 14
x25-profile frame1 dte
exit
!
interface dialer1
encapsulation x25
exit
x25 route ^1234 interface serial1/0 dlci 13
x25 route ^1234 interface serial1/0 dlci 14
x25 route ^1234 interface dialer1
!
x25 profile frame1
x25 fail-over 20 interface dialer1
exit
!
Related Commands
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show x25 context |
Displays information about X.25 links. |
x25 profile |
Configures an X.25 profile without specifying any hardware-specific information. |
x25 hic
To set the highest incoming-only virtual circuit (VC) number, use the x25 hic interface configuration command.
x25 hic circuit-number
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
X.25 profile configuration
Command History
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 data terminal equipment (DTE). If you do not want any outgoing calls from your DTE, configure both ends to disable the two-way range (set the values of x25 ltc and x25 htc to 0) and configure an incoming-only range. Any incoming-only range must come before (that is, must be numerically less than) any two-way range. Any two-way range must come before any outgoing-only range.
Examples
The following example sets a valid incoming-only VC range of 1 to 5:
interface serial 0
x25 lic 1
x25 hic 5
Related Commands
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x25 lic |
Sets the lowest incoming-only VC number. |
x25 hoc
To set the highest outgoing-only virtual circuit (VC) number, use the x25 hoc interface configuration command.
x25 hoc circuit-number
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
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 data terminal equipment (DTE). If you do not want any incoming calls on your DTE, disable the two-way range (set the values of x25 ltc and x25 htc to 0) and configure an outgoing-only range. Any outgoing-only range must come after (that is, be numerically greater than) any other range.
Examples
The following example sets a valid outgoing-only VC range of 2000 to 2005:
interface serial 0
x25 loc 2000
x25 hoc 2005
Related Commands
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x25 loc |
Sets the lowest outgoing-only VC number. |
x25 hold-queue
To set the maximum number of packets to hold until a virtual circuit (VC) is able to send, use the x25 hold-queue command in interface configuration mode. To remove this command from the configuration file and restore the default value, use the no form of this command without an argument.
x25 hold-queue packets
no x25 hold-queue [packets]
Syntax Description
packets |
Number of packets. A hold queue value of 0 allows an unlimited number of packets in the hold queue. |
Defaults
10 packets
Command Modes
Interface configuration
X.25 profile configuration
Command History
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
x25 hold-vc-timer
To start the timer that prevents additional calls to a destination for a given period of time (thus preventing overruns on some X.25 switches caused by Call Request packets), use the x25 hold-vc-timer command in interface configuration mode. To restore the default value for the timer, use the no form of this command.
x25 hold-vc-timer minutes
no x25 hold-vc-timer
Syntax Description
minutes |
Number of minutes that calls to a previously failed destination will be prevented. Incoming calls are still accepted. |
Defaults
0 minutes
Command Modes
Interface configuration
X.25 profile configuration
Command History
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
x25 host
To define a static host name-to-address mapping, use the x25 host command in global configuration mode. To remove the host name, use the no form of the command.
x25 host name x121-address [cud call-user-data]
no x25 host name
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
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 "ocean". It then uses the name "ocean" 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 ocean 12345678
translate x25 ocean ppp 10.0.0.2 routing
Related Commands
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translate x25 |
Translates a request to another outgoing protocol connection type when that X.25 connection request to a particular destination address is received. |
x25 htc
To set the highest two-way virtual circuit (VC) number, use the x25 htc command in interface configuration mode or X.25 profile configuration mode.
x25 htc circuit-number
Syntax Description
circuit-number |
VC number from 1 to 4095, or 0 if there is no two-way VC range. |
Defaults
1024 for X.25 network service interfaces; 4095 for CMNS network service interfaces.
Command Modes
Interface configuration
X.25 profile configuration
Command History
Usage Guidelines
This command is applicable if the X.25 switch is configured for a two-way VC range. Any two-way VC range must come after (that is, be numerically larger than) any incoming-only range, and must come before any outgoing-only range.
Examples
The following example sets a valid two-way VC range of 5 to 25:
interface serial 0
x25 ltc 5
x25 htc 25
Related Commands
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cmns enable |
Enables the CMNS on a nonserial interface. |
x25 ltc |
Sets the lowest two-way VC number. |
x25 hunt-group
To create and maintain a hunt group, use the x25 hunt-group command in global configuration mode. To delete this hunt group, use the no form of this command.
x25 hunt-group name {rotary | vc-count}
no x25 hunt-group name
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. |
Defaults
No X.25 hunt group is created.
Command Modes
Global configuration
Command History
Usage Guidelines
Only one load-balancing distribution method can be selected for a hunt group, although one interface can participate in one or more hunt groups.
The rotary distribution method sends every call to the next available interface regardless of line speed and the number of available VCs on that interface.
The vc-count distribution method sends calls to the interface with the largest number of available logical channels. This method ensures a good load balance when you have lines of equal speed. If the line speeds are unequal, the vc-count method will favor the line with the higher speed. In cases where interfaces have the same line speed, the call is sent to the interface that is defined earliest in the hunt group.
To distribute calls equally among interfaces regardless of line speed, configure each interface with the same number of VCs.
With the vc-count distribution method, if a hunt group does not contain an operational interface, the call will be forwarded to the next route if one was specified. If a session is terminated on an interface within the hunt group, that interface now has more available VCs and it will be chosen next.
Examples
X.25 Load Balancing Using VC-Count Distribution Method: Example
In the following example, the vc-count distribution method is used on a hunt group that contains two serial interfaces that have different numbers of VCs. Assuming no sessions are being terminated at this time, the first 450 calls will be sent to Serial1, and subsequent calls will alternate between Serial0 and Serial1 until the interfaces are full.
interface serial0
description 56k link supporting 50 virtual circuits
x25 htc 50
!
interface serial1
description T1 line supporting 500 virtual circuits
x25 htc 500
!
x25 hunt-group hg-vc vc-count
interface serial0
interface serial1
!
Hunt Group Configuration: Example
The following example shows the creation of hunt group "HG1" with serial interfaces 1 and 2 and two specific XOT target IP addresses (172.17.125.54 and 172.17.125.34). Hunt group "HG1" is configured to use rotary distribution method. The example also shows the creation of hunt group "HG2" with serial interfaces 0 and 3. Hunt group "HG2" will use vc-count distribution method.
x25 hunt-group HG1 rotary
interface serial 1
interface serial 2
xot 172.17.125.54
xot 172.17.125.34
exit
x25 hunt-group HG2 vc-count
interface serial 0
interface serial 3
Related Commands
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show x25 hunt-group |
Displays X.25 hunt groups, detailed interface statistics, and distribution methods. |
x25 idle
To define the period of inactivity after which the router can clear a switched virtual circuit (SVC), use the x25 idle command in interface configuration mode.
x25 idle minutes [seconds]
Syntax Description
Defaults
0 minutes (the SVC is kept open indefinitely)
Command Modes
Interface configuration
X.25 profile configuration
Command History
Usage Guidelines
Calls originated and terminated by the router are cleared; packet assembler/disassembler and switched virtual circuits are not affected. To clear one or all virtual circuits at once, use the clear x25 privileged EXEC command. Use the show interfaces and show x25 vc privileged EXEC commands to display the configured timeout values.
Examples
The following example sets a 5-minute wait period before an idle circuit is cleared:
interface serial 2
x25 idle 5
The following example clears an X.25 encapsulation VC after the VC remains idle for 1 minute and 10 seconds:
interface Serial0/0
description connects to tester s1/0
ip address 10.132.0.8 255.255.255.0
encapsulation x25
x25 address 2xx8xx
x25 idle 1 10
x25 map ip 10.132.0.9 2xx9xx
clock rate 64000
end
The x25 idle 0 30 command would change this configuration to clear the X.25 encapsulation VC after the VC remains idle for 30 seconds. See the description for the x25 map command for information on setting the idle timer using that command.
Related Commands
x25 ip-precedence
To enable the Cisco IOS software to use the IP precedence value when it opens a new virtual circuit (VC), use the x25 ip-precedence command in interface configuration mode. To cause the Cisco IOS software to ignore the precedence value when opening VCs, use the no form of this command.
x25 ip-precedence
no x25 ip-precedence
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
Usage Guidelines
This feature is useful only for Defense Data Network (DDN) or Blacker Front End (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
x25 ips
To set the interface default maximum input packet size to match that of the network, use the x25 ips interface configuration command.
x25 ips bytes
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
Usage Guidelines
X.25 network connections have a default maximum input packet size set by the network administrator. Larger packet sizes require less overhead processing. To send a packet larger than the X.25 packet size over an X.25 virtual circuit, the Cisco IOS software must break the packet into two or more X.25 packets with the more data bit (M-bit) set. The receiving device collects all packets with the M-bit set and reassembles the original packet.
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
x25 lic
To set the lowest incoming-only virtual circuit (VC) number, use the x25 lic interface configuration command.
x25 lic circuit-number
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
X.25 profile configuration
Command History
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
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x25 hic |
Sets the highest incoming-only VC number. |
x25 linkrestart
To force X.25 Level 3 (packet level) to restart when Level 2 (Link Access Procedure, Balanced [LAPB], the link level) resets, use the x25 linkrestart command in interface configuration mode. To disable this function, use the no form of this command.
x25 linkrestart
no x25 linkrestart
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
X.25 profile configuration
Command History
Examples
The following example disables the link-level restart:
interface serial 3
no x25 linkrestart
x25 loc
To set the lowest outgoing-only virtual circuit (VC) number, use the x25 loc interface configuration command.
x25 loc circuit-number
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
X.25 profile configuration
Command History
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
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x25 hoc |
Sets the highest outgoing-only VC number. |
x25 ltc
To set the lowest two-way virtual circuit (VC) number, use the x25 ltc interface configuration command.
x25 ltc circuit-number
Syntax Description
circuit-number |
VC number from 1 to 4095, or 0 if there is no two-way VC range. |
Defaults
1
Command Modes
Interface configuration
X.25 profile configuration
Command History
Usage Guidelines
This command is applicable if you have the X.25 switch configured for a two-way virtual circuit range. Any two-way virtual circuit range must come after (that is, be numerically larger than) any incoming-only range, and must come before any outgoing-only range.
Examples
The following example sets a valid two-way virtual circuit range of 5 to 25:
interface serial 0
x25 ltc 5
x25 htc 25
Related Commands
|
|
|
|---|---|
x25 htc |
Sets the highest two-way VC number. |
x25 map
To set up the LAN protocols-to-remote-host mapping, use the x25 map command in interface configuration or X.25 profile configuration mode. To retract a prior mapping, use the no form of this command.
x25 map protocol address [protocol2 address2 [...[protocol9 address9]]] x121-address [option]
no x25 map protocol address x121-address
Syntax Description
Defaults
No LAN protocol-to-remote-host mapping is set up.
Command Modes
Interface configuration
X.25 profile configuration
Command History
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.
Two methods are available to encapsulate traffic: Cisco's long-available encapsulation method and the Internet Engineering Task Force (IETF) standard method defined in RFC 1356; the latter allows hosts to exchange several protocols over a single virtual circuit. Cisco's encapsulation method is the default (for backward compatibility) unless the interface configuration command specifies the ietf keyword.
When you configure multiprotocol maps, you can specify a maximum of nine protocol and address pairs in an x25 map command. A multiprotocol map can specify a single address for all the supported protocols. However, if IP and TCP header compression are both specified, the same IP address must be given for both protocols.
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 VC requires memory and computation resources, compression must be used with care and monitored to maintain acceptable resource usage and overall performance.
Bridging is supported only if you are using Cisco's traditional encapsulation method. For correct operation, bridging maps must specify the broadcast option. Because 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.
Open Shortest Path First (OSPF) Protocol treats a nonbroadcast, multiaccess network such as X.25 in much the same way as it treats a broadcast network by requiring the selection of a designated router. In earlier releases of the Cisco IOS software, this selection required manual assignment in the OSPF configuration using the neighbor router configuration command. When the x25 map command is included in the configuration with the broadcast, and the ip ospf network command with the broadcast keyword is configured, there is no need to configure any neighbors manually. OSPF will run over the X.25 network as a broadcast network. (Refer to the ip ospf network interface configuration command for more detail.)
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 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 have 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.
Table 108 lists the protocols supported by X.25.
|
|
|
|---|---|
appletalk |
AppleTalk |
bridge |
Bridging1 |
clns |
ISO Connectionless Network Service |
compressedtcp |
TCP/IP header compression |
decnet |
DECnet |
ip |
IP |
ipx |
Novell IPX |
pad |
Packet assembler/disassembler (PAD) links2 |
qllc |
System Network Architecture (SNA) encapsulation in X.253 |
1 Bridging traffic is supported only for Cisco's traditional encapsulation method, so a bridge map cannot specify other protocols. 2 PAD maps are used to configure session and protocol translation access, therefore, this protocol is not available for multiprotocol encapsulation. 3 Qualified Logical Link Control (QLLC) is not available for multiprotocol encapsulation. |
Note The Connection-Mode Network Service (CMNS) map form is obsolete; its function is replaced by the enhanced x25 route command.
Table 109 lists the map options supported by X.25 when you use the x25 map command.
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 172.20.2.5 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 an 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.
In the following example, the VC times out 10 seconds after the circuit becomes idle (the setting configured in the x25 map command, rather than the x25 idle command):
interface Serial0/0
description connects to tester s1/0
ip address 10.132.0.8 255.255.255.0
encapsulation x25 dce
x25 address 2xx8xx
x25 idle 0 20
x25 map ip 10.132.0.9 2xx9xx idle 0 10
clock rate 64000
end
The settings for the x25 map command have higher precedence over the timeout period configured using the x25 idle command.
Related Commands
x25 map bridge
To configure an Internet-to-X.121 address mapping for bridging of packets in X.25 frames, use the x25 map bridge command in interface configuration mode. To disable the Internet-to-X.121 address mapping, use the no form of this command.
x25 map bridge x121-address broadcast [option]
Syntax Description
Defaults
No bridging over X.25 is configured.
Command Modes
Interface configuration
Command History
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.
Table 110 lists x25 map bridge options.
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
|
|
|
|---|---|
x25 map |
Sets up the LAN protocols-to-remote host mapping. |
x25 address |
Sets the X.121 address of a particular network interface. |
x25 map cmns
The x25 map cmns command is replaced by the enhanced x25 route command. See the description of the x25 route command in this chapter for more information.
x25 map compressedtcp
To map compressed TCP traffic to an X.121 address, use the x25 map compressedtcp command in interface configuration mode. To delete a TCP/IP header compression map for the link, use the no form of this command.
x25 map compressedtcp ip-address [protocol2 address2 [...[protocol9 address9]]]
x121-address [option]
no x25 map compressedtcp address [protocol2 address2 [...[protocol9 address9]]]
x121-address
Syntax Description
ip-address |
IP address. |
protocol |
(Optional) Protocol type, entered by keyword. Supported protocols are entered by keyword, as listed in Table 108 earlier in this chapter. 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 109 earlier in this chapter. |
Defaults
No mapping is configured.
Command Modes
Interface configuration
Command History
Usage Guidelines
Cisco supports RFC 1144 TCP/IP header compression (THC) on serial lines using HDLC and X.25 encapsulation. THC encapsulation is only slightly different from other encapsulation traffic, but these differences are worth noting. The implementation of compressed TCP over X.25 uses one virtual circuit to pass the compressed packets. Any IP traffic (including standard TCP) is separate from TCH traffic; it is carried over separate IP encapsulation virtual circuits or identified separately in a multiprotocol virtual circuit.
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
|
|
|
|---|---|
x25 map |
Sets up the LAN protocols-to-remote host mapping. |
x25 map pad
To configure an X.121 address mapping for packet assembler/disassembler (PAD) access over X.25, use the x25 map pad interface configuration command.
x25 map pad x121-address [option]
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 109 earlier in this chapter. |
Defaults
No specific options are used for PAD access.
Command Modes
Interface configuration
Command History
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
|
|
|
|---|---|
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. |
x25 map rbp local
To configure a router to establish X.25 circuits in response to incoming TCP connections on a specified TCP port, and to use record boundary preservation (RBP) to transfer data between the TCP session and the corresponding X.25 circuit, use the x25 map rbp local command in interface configuration mode. To delete the map, use the no form of this command.
x25 map rbp x121-address [cud string] local port port [cug group-number] [packetsize in-size out-size] [recordsize size] [reverse] [roa name] [throughput in out] [transit-delay milliseconds] [windowsize in-size out-size] q-bit
no x25 map rbp x121-address [cud string] local port port
Syntax Description
Defaults
No SVC is configured.
Command Modes
Interface configuration
Command History
|
|
|
|---|---|
12.2(8)T |
This command was introduced. |
12.4(11)T |
The q-bit optional keyword was added. |
Usage Guidelines
RBP enables X.25 hosts to exchange data with TCP/IP hosts via TCP sessions while maintaining X.25 packet boundaries.
When the x25 map rbp local command is configured, the router will listen for a request for a TCP connection to the specified TCP port. When the connection request is accepted, the router will then attempt to place an X.25 call on the interface on which the command was configured, using the X.25 address of the interface as the calling address, the X.121 address specified in the command as the destination address, and the call user data specified in the command. If the call is not successfully completed, the TCP connection will be closed.
The number of connections that may be established to the TCP port is limited only by router resources (such as memory, processor utilization, and available X.25 circuits).
When connections that will be established by the TCP/IP host are configured, the local TCP port number must be unique, with the exception that the same TCP port number may be configured once on each of multiple X.25 interfaces that will not be active simultaneously; this includes the case in which one X.25 interface is configured as a backup interface for another X.25 interface.
No information from the TCP connection is included in the X.25 Call packet sent to the X.25 host.
Examples
interface Serial1/0
encapsulation x25 dce
x25 address 13133
x25 map rbp 12131 local port 9999
Related Commands
x25 map rbp remote
To configure a router to establish TCP sessions in response to incoming X.25 calls, and to use record boundary preservation (RBP) to transfer data between the X.25 circuit and the corresponding TCP session, use the x25 map rbp remote command in interface configuration mode. To delete the map, use the no form of this command.
x25 map rbp x121-address [cud string] remote host ip-address port port [accept-reverse] [recordsize size] [source-interface interface] q-bit
no x25 map rbp x121-address [cud string] remote host port port
Syntax Description
Defaults
No SVC is configured.
Command Modes
Interface configuration
Command History
|
|
|
|---|---|
12.2(8)T |
This command was introduced. |
12.4(11)T |
The q-bit optional keyword was added. |
Usage Guidelines
RBP enables X.25 hosts to exchange data with TCP/IP hosts via TCP sessions while maintaining X.25 packet boundaries.
The router will accept an incoming X.25 call if the source address and call user data in the call request match the values configured in the x25 map rbp remote command. If the cud parameter is specified in the command, the call user data in the incoming call must match the configured value exactly. If the cud parameter is not specified in the command, the call user data must not conflict with any protocol ID recognized by the router, but it is otherwise ignored.
If an incoming call requests reverse charging, and the accept-reverse option is not specified in the matching map, the call will be refused.
If the incoming call is accepted, the router will attempt to open a TCP connection to a configured IP address and TCP port using a dynamically assigned local TCP port number. If the TCP connection cannot be opened, the X.25 call will be cleared.
The number of X.25 calls that may be accepted is limited only by router resources.
No information from the X.25 call packet is provided to the TCP/IP host.
Examples
interface Serial1/0
encapsulation x25 dce
x25 address 12030
x25 map rbp 12132 remote host 10.0.0.1 port 9999
Related Commands
x25 modulo
To set the window modulus, use the x25 modulo interface configuration command.
x25 modulo modulus
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
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
x25 nvc
To specify the maximum number of virtual circuits (VCs) that a protocol can have open simultaneously to one host, use the x25 nvc command in interface configuration mode. To increase throughput across networks, you can establish up to eight virtual circuits to a host and protocol.
x25 nvc count
Syntax Description
Defaults
1
Command Modes
Interface configuration
X.25 profile configuration
Command History
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 the x25 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
x25 ops
To set the interface default maximum output packet size to match that of the network, use the x25 ops interface configuration command.
x25 ops bytes
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
X.25 profile configuration
Command History
Usage Guidelines
X.25 networks use maximum output packet sizes set by the network administrator. Larger packet sizes are better because smaller packets require more overhead processing. To send a packet larger than the X.25 packet size over an X.25 virtual circuit, the Cisco IOS software must break the packet into two or more X.25 packets with the more data bit (M-bit) set. The receiving device collects all packets with the M-bit set and reassembles the original packet.
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
|
|
|
|---|---|
x25 ips |
Sets the interface default maximum input packet size to match that of the network. |
x25 pad-access
To cause the packet assembler/disassembler (PAD) software to accept PAD connections only from statically mapped X.25 hosts, use the x25 pad-access command in interface configuration mode. To disable checking maps on PAD connections, use the no form of this command.
x25 pad-access
no x25 pad-access
Syntax Description
This command has no arguments or keywords.
Defaults
Accept PAD connections from any host.
Command Modes
Interface configuration
Command History
Usage Guidelines
By default, all PAD connection attempts are processed for session creation or protocol translation, subject to the configuration of those functions. If you use the x25 pad-access command, PAD connections are processed only for incoming calls with a source address that matches a statically mapped address configured with the x25 map pad interface configuration command. PAD connections are refused for any incoming calls with a source address that has not been statically mapped.
Examples
The following example restricts incoming PAD access on the interface to attempts from the host with the X.121 address 000000010300:
interface serial 1
x25 pad-access
x25 map pad 000000010300
Related Commands
x25 profile
To configure an X.25 profile without allocating any hardware specific information, use the x25 profile command in global configuration mode. To delete this profile, use the no form of this command.
x25 profile name {dce | dte | dxe}
no x25 profile name
Syntax Description
Defaults
A DCE interface is specified.
Command Modes
Global configuration
Command History
Usage Guidelines
You can enable many X.25 commands in X.25 profile configuration mode. Table 111 lists the following X.25 commands in X.25 profile configuration mode, which you may use to create your X.25 profile.
Table 112 lists LAPB commands in X.25 configuration mode, which you may use to create your X.25 profile.
Examples
The following example shows the NetworkNodeA profile being set as a DCE interface, and with x25 htc, x25 idle, x25 accept-reverse, and x25 modulo commands enabled:
Router(config)# x25 profile NetworkNodeA dce
Router(config-x25)# x25 htc 128
Router(config-x25)# x25 idle 5
Router(config-x25)# x25 accept-reverse
Router(config-x25)# x25 modulo 128
Related Commands
|
|
|
|---|---|
show x25 profile |
Displays information about configured X.25 profiles. |
x25 pvc (encapsulation)
To establish an encapsulation permanent virtual circuit (PVC), use the encapsulating version of the x25 pvc command in interface configuration mode. To delete the PVC, use the no form of this command with the appropriate channel number.
x25 pvc circuit protocol address [protocol2 address2 [...[protocol9 address9]]] x121-address
[option]
no x25 pvc circuit
Syntax Description
circuit |
Virtual-circuit channel number, which must be less than the virtual circuits assigned to the switched virtual circuits (SVCs). |
protocol |
Protocol type, entered by keyword. Supported protocols are listed in Table 113. As many as nine protocol and address pairs can be specified in one command line. |
address |
Protocol address of the host at the other end of the PVC. |
x121-address |
X.121 address. |
option |
(Optional) Provides additional functionality or allows X.25 parameters to be specified for the PVC. Can be any of the options listed in Table 114. |
Defaults
The PVC window and maximum packet sizes default to the interface default values.
Command Modes
Interface configuration
Command History
Usage Guidelines
PVCs are not supported for ISO Connection-Mode Network Service (CMNS).
You no longer need to specify a datagram protocol-to-address mapping before you can set up a PVC; a map is implied from the PVC configuration. Configurations generated by the router will no longer specify a map for encapsulating PVCs.
When configuring a PVC to carry CLNS traffic, use the X.121 address as the subnetwork point of attachment (SNPA) to associate the PVC with a CLNS neighbor configuration. When configuring a PVC to carry transparent bridge traffic, the X.121 address is required to identify the remote host to the bridging function. Other encapsulation PVCs do not require an X.121 address.
Table 113 lists supported protocols.
|
|
|
|---|---|
appletalk |
AppleTalk |
bridge |
Bridging1 |
clns |
OSI Connectionless Network Service |
compressedtcp |
TCP/IP header compression |
decnet |
DECnet |
ip |
IP |
ipx |
Novell IPX |
qllc |
SNA encapsulation in X.252 |
1 Bridging traffic is supported only for Cisco's traditional encapsulation method, so a bridge PVC cannot specify other protocols. 2 QLLC is not available for multiprotocol encapsulation. |
Table 114 lists supported X.25 PVC options.
Examples
The following example establishes a PVC on channel 2 to encapsulate VINES and IP with the far host:
interface serial 0
x25 ltc 5
x25 pvc 2 vines 60002A2D:0001 ip 172.20.170.91 11110001
Related Commands
|
|
|
|---|---|
x25 map |
Sets up the LAN protocols-to-remote host mapping. |
x25 pvc (switched PVC to SVC)
To configure a switched permanent virtual circuit (PVC) to a switched virtual circuit (SVC) for a given interface, use the switched PVC to SVC version of the x25 pvc interface configuration command.
x25 pvc number1 svc x121-address [flow-control-options] [call-control-options]
Syntax Description
number1 |
Logical channel ID of the PVC. Value must be lower than any range of circuit numbers defined for SVCs. |
svc |
Specifies a SVC type. |
x121-address |
Destination X.121 address for opening an outbound SVC and source X.121 address for matching an inbound SVC. |
flow-control-options |
(Optional) Adds certain features to the mapping specified. It can be any of the options listed in Table 115. |
call-control-options |
(Optional) Adds certain features to the mapping specified. It can be any of the options listed in Table 116. |
Defaults
This command has no default values.
Command Modes
Interface configuration
Command History
Usage Guidelines
The PVC window and maximum packet sizes default to the interface default values. The default idle time comes from the interface on which the x25 pvc command is configured, not the interface on which the call is sent/received.
PVC circuit numbers must come before (that is, be numerically smaller than) the circuit numbers allocated to any SVC range.
On an outgoing call, the packet size facilities and window size facilities will be included. The call will be cleared if the call accepted packet specifies different values.
On an incoming call, requested values that do not match the configured values will be refused.
Table 115 lists the flow control options supported by X.25 during PVC to SVC switching.
Table 116 lists the call control options supported by X.25 during PVC to SVC switching.
Examples
The following example configures PVC to SVC switching between two serial interfaces:
x25 routing
interface serial0
encapsulation x25
x25 address 201700
x25 ltc 128
x25 idle 2
interface serial2
encapsulation x25 dce
x25 address 101702
x25 route ^20 interface serial0
x25 route ^10 interface serial2
interface serial0
x25 pvc 5 svc 101601 packetsize 128 128 windowsize 2 2 no-incoming
x25 pvc 6 svc 101602 packetsize 128 128 windowsize 2 2 no-outgoing idle 0
x25 pvc 7 svc 101603 packetsize 128 128 windowsize 2 2
Any call with a destination address beginning with 20 will be routed to serial interface 0. Any call with a destination address beginning with 10 will be routed to serial interface 2. (Note that incoming calls will not be routed back to the same interface from which they arrived.)
Traffic received on PVC 5 on serial interface 0 will cause a call to be placed from address 201700 to the X.121 address 101601. The routing table will then forward the call to serial interface 2. If no data is sent or received on the circuit for two minutes, the call will be cleared, as defined by the x25 idle command. All incoming calls from 101601 to 201700 will be refused, as defined by the no-incoming attribute.
The second x25 pvc command configures the circuit to allow incoming calls from 101602 to 201700 to be connected to PVC 6 on serial interface 1. Because idle is set to 0, the call will remain connected until cleared by the remote host or an X.25 restart. Because outgoing calls are not permitted for this connection, if traffic is received on PVC 6 on serial interface 0 before the call is established, the traffic will be discarded and the PVC will be reset.
The last x25 pvc command configures the circuit to accept an incoming call from 101603 to 201700 and connects the call to PVC 7 on serial interface 0. If no data is sent or received on the circuit for two minutes, the call will be cleared. If traffic is received on PVC 7 on serial interface 0 before the call is established, a call will be placed to 101503 to 201700.
x25 pvc (switched)
To configure a switched permanent virtual circuit (PVC) for a given interface, use the switched version of the x25 pvc interface configuration command.
x25 pvc number1 interface type number pvc number2 [option]
Syntax Description
number1 |
PVC number that will be used on the local interface (as defined by the primary interface command). |
interface |
Required keyword to specify an interface. |
type |
Remote interface type. |
number |
Remote interface number. |
pvc |
Required keyword to specify a switched PVC. |
number2 |
PVC number that will be used on the remote interface. |
option |
(Optional) Adds certain features to the mapping specified; can be either option listed in Table 117. |
Defaults
The PVC window and maximum packet sizes default to the interface default values.
Command Modes
Interface configuration
Command History
Usage Guidelines
You can configure X.25 PVCs in the X.25 switching software. As a result, data terminal equipment (DTE) devices that require permanent circuits can be connected to the router acting as an X.25 switch and have a properly functioning connection. X.25 resets will be sent to indicate when the circuit comes up or goes down.
PVC circuit numbers must come before (that is, be numerically smaller than) the circuit numbers allocated to any SVC range.
Table 117 lists the switched PVC options supported by X.25.
Examples
The following example configures a PVC connected between two serial interfaces on the same router. In this type of interconnection configuration, the alternate interface must be specified along with the PVC number on that interface. To make a working PVC connection, two commands must be specified, each pointing to the other, as this example illustrates.
interface serial 0
encapsulation x25
x25 ltc 5
x25 pvc 1 interface serial 1 pvc 1
interface serial 1
encapsulation x25
x25 ltc 5
x25 pvc 1 interface serial 0 pvc 1
x25 pvc (XOT)
To connect two permanent virtual circuits (PVCs) across a TCP/IP LAN, use the X.25-over-TCP (XOT) service form of the x25 pvc command in interface configuration mode.
x25 pvc number1 xot address interface serial string pvc number2 [option]
Syntax Description
number1 |
PVC number of the connecting device. |
xot |
Indicates two PVCs will be connected across a TCP/IP LAN using XOT. |
address |
IP address of the device to which you are connecting. |
interface serial |
Indicates the interface is serial. |
string |
Serial interface specification that accepts either a number or a string in model 7000 format (number/number) to denote the serial interface. |
pvc |
Indicates a PVC. |
number2 |
Remote PVC number on the target interface. |
option |
(Optional) Adds certain features for the connection; can be one or more of the options listed in Table 118. |
Defaults
The PVC window and packet sizes default to the interface default values.
The default for the xot-keepalive-period option is 60 seconds.
The default for the xot-keepalive-tries option is 4 tries.
Command Modes
Interface configuration
Command History
Usage Guidelines
Use the PVC tunnel commands to tell the Cisco IOS software what the far end of the PVC is connected to. The incoming and outgoing packet sizes and window sizes must match the remote PVC outgoing and incoming sizes.
It is recommended that the xot-source option be used on the remote host so that a consistent IP address is used for the connection.
Table 118 lists the PVC tunnel options supported by X.25.
Each XOT connection relies on a TCP session to carry traffic. To ensure that these TCP sessions remain connected in the absence of XOT traffic, use the service tcp-keepalives-in and service tcp-keepalives-out global configuration commands. If TCP keepalives are not enabled, the XOT PVCs might encounter problems if one end of the connection is reloaded. When the reloaded host attempts to establish a new connection, the other host refuses the new connection because it has not been informed that the old session is no longer active. Recovery from this state requires the other host to be informed that its TCP session is no longer viable so that it attempts to reconnect the PVC.
Also, TCP keepalives inform a router when an XOT switched virtual circuit (SVC) session is not active, thus freeing the router's resources.
Examples
The following example enters the parameters for one side of a connection destined for a platform other than the Cisco 7000 series with RSP7000:
service tcp-keepalives-in
service tcp-keepalives-out
interface serial 0
x25 pvc 1 xot 172.20.1.2 interface serial 1 pvc 2
The following example enters the parameters for one side of a connection destined for the Cisco 7000 series with RSP7000:
service tcp-keepalives-in
service tcp-keepalives-out
interface serial 0
x25 pvc 1 xot 172.20.1.2 interface serial 1/1 pvc 2
Refer to the section "X.25 and LAPB Configuration Examples" in the Cisco IOS Wide-Area Networking Configuration Guide for more complete configuration examples.
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