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The use of X.25 as a network backbone is becoming obsolete as modern networks change their backbones to newer technologies such as Frame Relay, ATM, and IP.
This process is largely achieved using X.25 profiles, which were created to streamline X.25 and LAPB configuration. X.25 profiles can contain existing X.25 and LAPB commands and, once created and named, can be simultaneously associated with more than one DLCI connection, using just the profile name.
X.25 Layers 2 and 3 are transparently supported over Annex G. LAPB treats the Frame Relay network like an X.25 network link and passes all of the data and control messages over the Frame Relay network.
Annex G provides the following benefits:
data communications equipment (DCE)---A network device or connection that comprises the network end of the user-to-network interface.
data-link connection identifier (DLCI)---Value that specifies a PVC or SVC in a Frame Relay network.
data terminal equipment (DTE)---A network device or connection that comprises the user end of the user-to-network interface.
data exchange equipment (DXE)---A network device or connection that allows dynamic cooperation with another station to act as a DTE or a DCE (whichever is required for connectivity).
Link Access Protocol, Balanced (LAPB)---Data link layer protocol in X.25.
permanent virtual circuit (PVC)---A permanently established logical association between two physically separate DTEs.
switched virtual circuit (SVC)---A virtual circuit that is dynamically established on demand and torn down when transmission is complete.
virtual circuit (VC)---A logical association between two physically separate DTEs.
The following restrictions apply to Annex G:
This feature is supported on these platforms:
Before enabling Annex G connections you must establish a Frame Relay connection. See the sections "Configuration Tasks" and "Configuration Examples" for further details. For more information about configuring Frame Relay, refer to the chapter "Configuring Frame Relay" in the Wide-Area Networking Configuration Guide for Cisco IOS Release 12.0.
None.
Router(config)# x25 routing 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 Router(config-x25)# end Router(config)# x25 profile NetworkNodeB dce Router(config-x25)# x25 address 1111 Router(config-x25)# end Router(config)# interface serial1 Router(config-if)# encapsulation frame-relay Router(config-if)# frame-relay interface-dlci 20 Router(config-fr-dlci)# x25-profile NetworkNodeA Router(config-fr-dlci)# end Router(config)# interface serial1 Router(config-if)# frame-relay interface-dlci 30 Router(config-fr-dlci)# x25-profile NetworkNodeA Router(config-fr-dlci)# end Router(config)# interface serial1 Router(config-if)# frame-relay interface-dlci 40 Router(config-fr-dlci)# x25-profile NetworkNodeB Router(config-fr-dlci)# end Router(config)# x25 route 2000 interface serial1 dlci 20 Router(config)# x25 route 3000 interface serial1 dlci 30 Router(config)# x25 route 4000 interface serial1 dlci 40
This section documents new or modified commands used to configure the Annex G (X.25 over Frame Relay) feature. All other commands used with this feature are documented in the Cisco 12.0 Command References.
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. |
Privileged EXEC
This command first appeared in Cisco IOS Release 11.3. (This command replaces the clear x25-vc command, which first appeared in Cisco IOS Release 8.3.)
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.
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
You can use the master indexes or search online to find documentation of related commands.
clear xot
show x25 services
show x25 vc
For Annex G, use the Frame Relay DLCI interface configuration command x-25 profile to configure your X.25 profile to a DLCI connection. To remove this assignment, use the no form of this command.
frame-relay interface-dlci number [ietf | cisco] [voice-encap size]
no frame-relay interface-dlci number [ietf | cisco] [voice-encap size]
frame-relay interface-dlci number [protocol ip ip-address] (for a BOOTP server only)
number | DLCI number for the specified interface. |
ietf | cisco | (Optional) Encapsulation type: Internet Engineering Task Force (IETF) Frame Relay encapsulation or Cisco Frame Relay encapsulation. |
protocol ip ip-address | (Optional) Indicates the IP address of the main interface of a new router or access server onto which a router configuration file is to be automatically installed over a Frame Relay network. Use this option only when this device will act as the BOOTP server for automatic installation over Frame Relay. |
voice-encap size | (Supported on the Cisco MC3810 only.) Specifies that data segmentation will be used to support Voice over Frame Relay. The voice encapsulation size denotes the data segmentation size. For a list of recommended data segmentation sizes, see "Usage Guidelines." |
Interface configuration.
This command first appeared in Cisco IOS Release 10.0.
By issuing the frame-relay interface-dlci interface configuration command, you enter Frame Relay DLCI interface configuration mode (see the first example below). This gives you the following command options, which must be used with the relevant class or X.25-profile names you previously assigned:
A Frame Relay DLCI configured for Annex G can be thought of as a single logical X.25/LAPB interface. Therefore, any number of X.25 routes may be configured to route X.25 calls to that logical interface.
The frame-relay interface-dlci command is typically used for subinterfaces; however, it can also be used on main interfaces. Using the frame-relay interface-dlci command on main interfaces will enable the use of routing protocols on interfaces that use inverse ARP. The frame-relay interface-dlci command on a main interface is also valuable for assigning a specific class to a single PVC where special characteristics are desired. Subinterfaces are logical interfaces associated with a physical interface. You must specify the interface and subinterface before you can use this command to assign any DLCIs and any encapsulation or broadcast options. See the "Example" section for the sequence of commands.
This command is required for all point-to-point subinterfaces; it is also required for multipoint subinterfaces for which dynamic address resolution is enabled. It is not required for multipoint subinterfaces configured with static address mappings.
Use the protocol ip ip-address option only when your router or access server will act as the BOOTP server for autoinstallation over Frame Relay.
For the voice-encap option on the Cisco MC3810, set the data segmentation size based on the port access rate. Table 1 lists recommended data segmentation sizes for different port access rates. Also, when the voice-encap keyword is configured on the Cisco MC3810, all priority queuing, custom queuing, and weighted fair queuing is disabled on the interface.
| Port Access Rate | Recommended Data Segmentation Size1 |
|---|---|
64 kbps | 80 bytes |
128 kbps | 160 bytes |
256 kbps | 320 bytes |
512 kbps | 640 bytes |
1536 kbps (full T1) | 1600 bytes |
2048 kbps (full E1) | 1600 bytes |
| 1The data segmentation size is based for back-to-back Frame Relay. If sending traffic through an IGX with standard Frame Relay, add an extra 15 bytes to the recommended data segmentation size. |
For more information about automatically installing router configuration files over a Frame Relay network, see the "Loading System Images and Microcode" chapter in the Configuration Fundamentals Configuration Guide.
The following example shows an Annex G connection being created by assigning the X.25 profile "NetworkNodeA" to the Frame Relay DLCI interface 20 on interface serial 1 (having enabled Frame Relay encapsulation on that interface):
Router(config)# interface serial1 Router(config-if)# encapsulation frame-relay Router(config-if)# frame-relay interface-dlci 20 Router(config-fr-dlci)# x25-profile NetworkNodeA
The following example assigns DLCI 100 to serial subinterface 5.17:
Router(config)# interface serial 5 Router(config-if)# interface serial 5.17 Router(config-if)# frame-relay interface-dlci 100
You can use the master indexes or search online to find documentation of related commands.
frame-relay class
interface number | (Optional) Specific logical X.25 VC interface. |
dlci number | (Optional) Specific DLCI link. |
EXEC
This command first appeared in Cisco IOS Release 12.0(3)T.
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
Table 2 describes significant fields shown in the display.
| Field | Description |
|---|---|
address | Address to which interface is connected. |
state | State of the interface. Possible values are: R1- normal ready state. R2 - DTE restarting state. R3 - DCE restarting state. If state is R2 or R3, the interface is awaiting acknowledgment of a Restart packet. |
modulo | Modulo packet sequence numbering scheme. |
timer | Interface timer value (zero unless the interface state is R2 or R3). |
Defaults: idle VC timeout | Inactivity time before clearing VC. |
input/output window sizes | Default window sizes (in packets) for the interface. The x25 facility interface configuration command can be used to override these default values for the switched virtual circuits originated by the router. |
packet sizes | Default maximum packet sizes (in bytes) for the interface. The x25 facility interface configuration command can be used to override these default values for the switched virtual circuits originated by the router. |
Timers | Values of the X.25 timers: T10 through T13 for a DCE device. T20 through T23 for a DTE device. |
Channels | Virtual circuit ranges for this interface. |
RESTARTs | Restart packet statistics for the interface using the format Sent/Received. |
CALLs | Successful calls sent plus failed calls/calls received plus calls failed/calls forwarded plus calls failed. Calls forwarded are counted as calls sent. |
DIAGs | Diagnostic messages sent and received. |
You can use the master indexes or search online to find documentation of related commands.
show x25 vc
To view details of X.25 profiles on your router, issue the show x25 profile command in EXEC mode.
show x25 profile [name]
name | (Optional) Name of X.25 profile. |
EXEC
This command first appeared in Cisco IOS Release 12.0(3)T.
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
Table 3 describes significant fields shown in the display.
| Field | Description |
|---|---|
Number of references | Number of X.25 connections using this profile. |
In use by | Shows the interface and X.25 service using this profile. |
address | Address to which interface is connected. |
state | State of the interface. Possible values are R1- normal ready state. R2 - DTE restarting state. R3 - DCE restarting state. If state is R2 or R3, the interface is awaiting acknowledgment of a Restart packet. |
modulo | Value that determines the packet sequence numbering scheme used. |
timer | Interface timer value (zero unless the interface state is R2 or R3). |
Defaults: idle VC timeout | Inactivity time before clearing VC. |
input/output window sizes | Default window sizes (in packets) for the interface. The x25 facility interface configuration command can be used to override these default values for the switched virtual circuits originated by the router. |
packet sizes | Default maximum packet sizes (in bytes) for the interface. The x25 facility interface configuration command can be used to override these default values for the switched virtual circuits originated by the router. |
Timers | Values of the X.25 timers: T10 through T13 for a DCE device T20 through T23 for a DTE device |
Channels: | Virtual circuit ranges for this interface. |
You can use the master indexes or search online to find documentation of related commands.
show x25 vc
name | X.25 profile name that you assign. |
dce | Indicates a DCE interface. |
dte | Indicates a DTE interface. |
dxe | Indicates a DXE interface. |
dte
Global configuration
This command first appeared in the Cisco IOS Release 12.0(3)T.
Table 4 lists the following X.25 commands in X.25 configuration mode which you may use to create your X.25 profile:
| Command | Description |
|---|---|
x25 accept-reverse | Accepts all reverse charged calls. |
x25 address | Sets interface X.121 address. |
x25 alias | Defines an alias address pattern. |
x25 aodi | Enables AODI (Always On/Direct ISDN) Service. |
x25 default | Sets protocol for calls with unknown Call User Data. |
x25 facility | Sets explicit facilities for originated calls. |
x25 hic | Sets highest incoming channel. |
x25 hoc | Sets highest outgoing channel. |
x25 hold-queue | Sets limit on packets queued per circuit. |
x25 hold-vc-timer | Sets time to prevent calls to a failed destination. |
x25 htc | Sets highest two-way channel. |
x25 idle | Sets inactivity time before clearing SVC. |
x25 lic | Sets lowest incoming channel. |
x25 linkrestart | Restarts when LAPB resets. |
x25 loc | Sets lowest outgoing channel. |
x25 ltc | Sets lowest two-way channel. |
x25 map | Maps protocol addresses to X.121 address. |
x25 modulo | Sets operating standard. |
x25 nonzero-dte-cause | Allows non-zero DTE cause codes. |
x25 nvc | Sets maximum VCs simultaneously open to one host per protocol. |
x25 ops | Sets default maximum output packet size. |
x25 suppress-called-address | Omits destination address in outgoing calls. |
x25 suppress-calling-address | Omits source address in outgoing calls. |
x25 t10 | Sets DCE Restart Request retransmission timer. |
x25 t11 | Sets DCE Call Request retransmission timer. |
x25 t12 | Sets DCE Reset Request retransmission timer. |
x25 t13 | Sets DCE Clear Request retransmission timer. |
x25 threshold | Sets packet count acknowledgment threshold. |
x25 use-source-address | Uses local source address for forwarded calls. |
x25 win | Sets default input window (maximum unacknowledged packets). |
x25 wout | Sets default output window (maximum unacknowledged packets). |
Table 5 lists the following LAPB commands in X.25 configuration mode which you may use to create your X.25 profile:
| Command | Description |
|---|---|
N2 | Maximum number of attempts to transmit a frame. |
T1 | Retransmission timer. |
T2 | Explicit acknowledge deferral timer. |
T4 | Keepalive timer. |
interface-outage | Interface outage deadband (partial T3). |
k | Maximum number of outstanding frames (window size). |
modulo | Set frame numbering modulus. |
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
You can use the master indexes or search online to find documentation of related commands.
show x25 profile
To create an entry in the X.25 routing table (to be consulted for forwarding incoming calls and for placing outgoing packet assembler/disassembler (PAD) or protocol translation calls), use an appropriate form of the x25 route global configuration command. To remove an entry from the table, use the no form of the command.
x25 route [#position] [selection] [modification] disposition [xot-keepalive]
#position | (Optional) A pound sign (#) followed by a number designates the position in the routing table at which to insert the new entry. If no position value is given, the entry is appended to the end of the routing table. |
selection | (Optional) The selection options identify when the subsequent modification and disposition elements apply to an X.25 call; any or all variables may be specified for a route. See Table 6 in the "Usage Guidelines" section for the valid selection keyword and argument options. Although each individual selection criterion is optional, at least one selection or modification element must be specified in the x25 route command. |
modification | (Optional) Modifies the source or destination addresses of the selected calls. The standard regular expression substitution rules are used, where a match pattern and rewrite string direct the construction of a new string. See Table 7 in the "Usage Guidelines" section for the valid modification keyword and argument options. Although each individual modification is optional, at least one selection or modification element must be specified in the x25 route command. |
disposition | Specifies the disposition of a call matching the specified selection pattern. See Table 11 in the "Usage Guidelines" section for the valid disposition keyword and argument options. |
xot-keepalive | (Optional) Specifies an XOT keepalive period and number of XOT keepalive retries. XOT relies on TCP to detect when the underlying connection is dead. TCP detects a dead connection when transmitted data goes unacknowledged for a given number of attempts over a period of time. See Table 12 in the "Usage Guidelines" section for keepalive options. |
No entry is created in the X.25 routing table.
Global configuration
The enhanced x25 route command replaces the x25 map cmns command. The x25 route alias form of this command (supported in earlier releases) has been replaced by the x25 alias command.
The selection criteria source and dest-ext first appeared in Cisco IOS Release 11.3. The interface disposition to a CMNS destination first appeared in Cisco IOS Release 11.3; in prior releases, CMNS routing information was implied by maps defining an NSAP prefix for a CMNS hosts MAC address. The clear interface disposition option first appeared in Cisco IOS Release 11.3; in prior releases, the disposition was implicit in a route to the Null 0 interface. The modification elements are long-standing but newly applicable to all dispositions in Cisco IOS Release 11.3.
Selection options specify match criteria. When a call matches all selection criteria in an X.25 route, then the specified modification and disposition are used for the call.
As many as four selection options can be used to determine the route:
Table 6 lists the selection options for the x25 route command. At least one selection or modification element must be specified.
| Selection Options | Description |
|---|---|
destination-pattern | (Optional) Destination address pattern, which is a regular expression that can represent either one X.121 address (such as ^1111000$) or any address in a group of X.121 addresses (such as ^1111.*). |
source source-pattern | (Optional) Source address pattern, which is a regular expression that can represent either one X.121 source address (such as ^2222000$) or any address in a group of X.121 addresses (such as ^2222.*). |
dest-ext nsap-destination-pattern | (Optional) NSAP destination address pattern, which is a regular expression that can represent either an NSAP destination address (such as ^11.1111.0000$) or an NSAP prefix (such as ^11.1111.*). Note: A period (.) in the pattern is interpreted as a character wildcard, which will not interfere with a match to the actual period in the NSAP; if desired, an explicit character match may be used (such as ^11\.1111\..*). |
cud user-data-pattern | |
hunt-group name | Routes the selected call to the X.25 hunt group. The chosen router may vary depending on the hunt group configuration. |
Regular expressions are used to allow pattern-matching operations on the addresses and user data. A common operation is to do prefix matching on the X.121 DNIC field and route accordingly. The caret (^) is a special regular expression character that anchors the match at the beginning of the pattern. For example, the pattern ^3306 will match all X.121 addresses with a DNIC of 3306.
Addresses typically need to be modified when traffic from a private network that uses arbitrary X.121 addresses must transit a public data network, which must use its own X.121 addresses. The easiest way to meet the requirement is to specify in the x25 route command a way to modify the private address into a network X.121 address or to modify a network X.121 address into a private address. The addresses are modified so that no change to the private addressing scheme is required.
The modification options use the standard UNIX regular expression substitution operations to change an X.25 field. A pattern match is applied to an address field, which is rewritten as directed by a rewrite pattern.
Table 7 lists the modification options for the x25 route command. At least one selection or modification element must be specified.
| Modification Option | Description |
|---|---|
substitute-source rewrite-source | (Optional) Calling X.121 address rewrite pattern. The source address, source-pattern, and this rewrite-source pattern are used to form a new source address. If no source-pattern is specified, any destination-pattern match pattern is used. If neither match pattern is specified, a default match pattern of .* is used. See Table 8 and Table 9 for summaries of pattern and character matching, respectively. See Table 10 for a summary of pattern rewrite elements. |
substitute-dest rewrite-dest | (Optional) Called X.121 address rewrite pattern. The destination address, destination-pattern, and this rewrite-dest pattern are used to form a new destination address. If no destination-pattern is specified, a default match pattern of .* is used. See Table 8 and Table 9 for summaries of pattern and character matching, respectively. See Table 10 for a summary of pattern rewrite elements. |
Source address. A modification of the source address is directed by the rewrite string using one of three possible match patterns. If the source source-pattern selection option is defined, it is used with the source-rewrite string to construct the new source address; otherwise, a destination-pattern regular expression is used (for backward compatibility) or a wildcard regular expression (.*) is used. In the rewrite-source argument, the backslash character (\) indicates that the digit immediately following the argument selects a portion of the matched address to be inserted into the new called address.
Destination address. A modification of the destination address is directed by the rewrite string using one of two possible match patterns. If the destination-pattern selection option is defined, it is used with the destination-rewrite string to construct the new destination address; otherwise, a wildcard regular expression (.*) is used. In the rewrite-dest argument, the backslash character (\) indicates that the digit immediately following the argument selects a portion of the original called address to be inserted into the new called address.
Refer to Table 8, Table 9, and Table 10 respectively, for summaries of pattern matching, character matching, and pattern rewrite elements. Note that up to nine pairs of parentheses can be used to identify patterns to be included in the modified string. A more complete description of the pattern-matching characters is found in the "Regular Expressions" appendix in the Dial Solutions Command Reference.
| Pattern | Description |
|---|---|
* | Matches 0 or more occurrences of the preceding character. |
+ | Matches 1 or more occurrences of the preceding character. |
? | Matches 0 or 1 occurrences of the preceding character.1 |
| 1Precede the question mark with Ctrl-V to prevent the question mark from being interpreted as a help command. |
| Character | Description |
|---|---|
^ | Matches the beginning of the input string. |
$ | Matches the end of the input string. |
\char | Matches the single character char specified. |
. | Matches any single character. |
| Pattern | Description |
|---|---|
\0 | The pattern is replaced by the entire original address. |
\1...9 | The pattern is replaced by strings that match the first through ninth parenthetical part of the X.121 address. |
The xot-source disposition option can improve the resilience of the TCP connection if, for instance, a loopback interface is specified. By default, a TCP connection's source IP address is that of the interface used to initiate the connection; a TCP connection will fail if either the source or destination IP address is no longer valid. Because a loopback interface never goes down, its IP address is always valid. Any TCP connections originated using a loopback interface can be maintained as long as a path exists to the destination IP address, which may also be the IP address of a loopback interface.
Table 11 lists the disposition choices for the x25 route command. You must select one of these choices.
| Disposition | Description |
|---|---|
interface serial-interface | Routes the selected call to the specified X.25 serial interface. |
interface serial-interface dlci number | (Optional) Routes the X.25 call to the specified Annex G link. You must include the interface number as well as entering the DLCI number. You only need to do this if you want the router to accept switched calls, as well as originate them. |
interface cmns-interface mac mac-address | Routes the selected call out the specified broadcast interface via CMNS to the LAN destination station. The broadcast interface type can be Ethernet, Token Ring, or FDDI. The interface numbering scheme depends on the router interface hardware. |
xot ip-address [ip2-address [...[ip6-address]]] [xot-source interface] | Routes the selected call to the XOT host at the specified IP address. Subsequent IP addresses are tried, in sequence, only if XOT is unable to establish a TCP connection with a prior address. |
hunt-group name | Routes the selected call to the X.25 hunt group. The chosen route may vary depending on the hunt group configuration. |
clear | Terminates the call. |
TCP maintains each connection using a keepalive mechanism that starts with a default time period and number of retry attempts. If a received XOT connection is dispatched using a route with explicit keepalive parameters, those values will be used for the TCP connection. If an XOT connection is sent using a route with explicit keepalive parameters, those values will be used for the TCP connection.
Table 12 lists and describes the xot-keepalive options for the x25 route command.
| XOT-Keepalive Option | Description |
|---|---|
xot-keepalive-period seconds | Number of seconds between keepalives for XOT connections. The default is 60 seconds. |
xot-keepalive-tries count | Number of times TCP keepalives should be sent before dropping the connection. The default value is 4 times. |
If a matching route is found, the incoming call is forwarded to the next hop depending on the routing entry. If no match is found, the call is cleared. If the route specifies a serial interface running X.25 or a broadcast interface running CMNS, the router attempts to forward the call to that host. If the interface is not operational, the subsequent routes are checked for forwarding to an operational interface. If the interface is operational but out of available virtual circuits, the call is cleared. Otherwise, the expected Clear Request or Call Accepted message is forwarded back toward the originator. A call cannot be forwarded out the interface on which it arrived.
If the matching route specifies an XOT disposition, a TCP connection is established to port 1998 at the specified IP address, which must be an XOT host. The Call Request packet is forwarded to the remote host, which applies its own criteria to handle the call. If, upon receiving an XOT call, a routing table entry is not present, or the destination is unavailable, a Clear Request is sent back and the TCP connection is closed. Otherwise, the call is handled and the expected Clear Request or Call Accepted packet is returned. Incoming calls received via XOT connections that match a routing entry specifying an XOT destination are cleared. This restriction prevents Cisco routers from establishing an XOT connection to another router that would establish yet another XOT connection.
The following example uses regular expression pattern matching characters to match just the initial portion of the complete X.25 address. Any call with a destination address beginning with 3107 that is received on an interface other than serial 0 is forwarded to serial 0.
x25 route ^3107 interface serial 0
The following example routes the X.25 call to the specified Annex G DLCI link. You must include both interface number and DLCI number. It is this combination of both these numbers that indicates the logical X.25 interface over Frame Relay.
x25 route ^2222 interface serial 1 dlci 20
The following example prevents X.25 routing for calls that do not specify a source address:
x25 route source ^$ clear
The following example configures alternate XOT hosts for the routing entry. If the first address listed is not available, subsequent addresses are tried until a connection is made. If no connection can be formed, the call is cleared.
x25 route ^3106$ xot 172.20.2.5 172.20.7.10 172.10.7.9
The following example clears calls that contain a 3 in the source address. The disposition keyword clear is new:
x25 route source 3 clear
The following example clears calls that contain two consecutive 3's in the source address:
x25 route source 33 clear
The following example clears a call to the destination address 9999:
x25 route ^9999$ clear
The following example specifies a route for specific source and destination addresses. (The ability to combine source and destination patterns is a new feature.)
x25 route ^9999$ source ^333$ interface serial 0
The following example routes the call to the XOT host at the specified IP address. The disposition keyword xot is new. In prior releases the keyword ip was used.
x25 route ^3333$ xot 172.21.53.61
The following example routes calls containing the destination extension address preamble 11.1234:
x25 route dest-ext ^11.1234.* interface serial 0
The following example rewrites the destination address as 9999. There must be a minimum of four 8's in the address. (8888888 will change to 9999.)
x25 route 8888 substitute-dest 9999 interface serial 0
The following example substitutes only part of the destination address. "^88" specifies the original destination string must begin with 88. "(.*)" indicates the string can end with any number, 0-9, and can be more than one digit. "99\1" changes the destination address to 99 plus whatever matches ".*" in the original destination address. For example, 8881 will change to 9981.
x25 route ^88(.*) substitute-dest 99\1 interface serial 0
The following example substitutes only part of the destination address and also removes a specified number of digits from the address. "^88" specifies the original destination string must begin with 88. "(..)" matches any two digits. "(.*)" specifies the string can end with any number, 0-9, and can occur zero or more times. Thus any address that starts with 88 and has four or more digits will be rewritten to start with 99 and omit the third and fourth digits. For example, 881234 will change to 9934.
x25 route ^88(..)(.*) substitute-dest 99\2 interface serial 0
The following example looks for a specified destination address and changes the source address. "9999" is the destination address. The original source address changes to "2222" because the call is made to the destination 9999.
x25 route ^9999$ substitute-source 2222 interface serial 0
The following example rewrites the source address based on the source address. "9999" matches any destination address with four consecutive 9s. "^...(.*)" matches any source address with at least three digits; the command removes the first three digits and rewrites any digits after the first three as the new source address. For example, a call to 9999 from the source address 77721 will be forwarded using the calling address 21 and the called address 9999.
x25 route 9999 source ^...(.*) substitute-source \1 interface serial 0
The following example adds a digit to the source and destination addresses patterns. "09990" is the destination address pattern. The source can be any address. "9\0" specifies to add a leading 9 to the destination address pattern. "3\0" specifies to add a leading 3 to the source address pattern. For example, a call using source 03330 and destination 09990 will change to 303330 and 909990, respectively.
x25 route 09990 source .* substitute-dest 9\0 substitute-source 3\0 interface serial 0
You can use the master indexes or search online to find documentation of related commands.
show x25 route
The debug x25 command has been modified to accommodate Annex G. Use the debug x25 annexg command to debug Annex G.
 | Caution This command is processor intensive and can render the router useless. Use this command only when the aggregate of all reportable X.25 traffic is fewer than five packets per second. The generic forms of this command should be restricted to low-speed, low-usage links running below 19.2 kbps. Because the debug x25 vc command and the debug x25 vc events command display traffic for only a small subset of virtual circuits, they are safer to use under heavy traffic conditions, as long as events for that virtual circuit are fewer than 25 packets per second. |
To display information about all X.25 traffic, including traffic for X.25, CMNS, and XOT services, use the debug x25 EXEC command. The no form of this command disables debugging output.
[no] debug x25 [events | all]To display information about a specific X.25 service class, use the following form of the debug x25 EXEC command:
[no] debug x25 {only | cmns | xot} [events | all]To display information about a specific X.25 or CMNS context, use the following form of the debug x25 EXEC command:
[no] debug x25 interface {serial-interface | cmns-interface mac mac-address} [events | all]To display information about a specific X.25 or CMNS virtual circuit, use the following form of the debug x25 EXEC command:
[no] debug x25 interface {serial-interface | cmns-interface mac mac-address} vc numberTo display information about traffic for all virtual circuits using a given number, use the following form of the debug x25 EXEC command. The no form of this command removes the filter for a particular virtual circuit from the debug x25 all or debug x25 events output.
[no] debug x25 vc number [events | all]To display information about traffic to or from a specific XOT host, use the following form of the debug x25 xot EXEC command:
[no] debug x25 xot [remote ip-address [port number]] [local ip-address [port number]]To display information about an interface running PPP over an X.25 session, use the debug x25 aodi EXEC command. The no form of this command disables debugging output.
[no] debug x25 aodiTo display information about interfaces running an Annex G (X.25 over Frame Relay) session, use the debug x25 annexg EXEC command. The no form of this command disables debugging output.
[no] debug x25 annexg
events | (Optional) Displays all traffic except data and relative rate (RR) packets. |
all | (Optional) Displays all traffic. This is the default. |
only | cmns | xot | Displays information about the specified services: X.25 only, CMNS, or XOT. |
annexg | Displays X.25 over Frame Relay (Annex-G) events |
aodi | Displays AO/DI events and processing information. |
serial-interface | X.25 serial interface. |
cmns-interface mac mac-address | CMNS interface and remote hosts MAC address. The interface type can be Ethernet, Token Ring, or FDDI. |
vc number | Virtual circuit number, in the range 1 to 4095. |
remote ip-address [port number] | (Optional) Remote IP address and, optionally, a port number in the range 1 to 65535. |
local ip-address [port number] | (Optional) Local host IP address and, optionally, a port number in the range 1 to 65535. |
This command is particularly useful for diagnosing problems encountered when placing calls. The debug x25 all output includes data, control messages, and flow control packets for all of the router's virtual circuits.
All debug x25 command forms can take either the events or all keyword. The keyword all is the default and causes all packets meeting the other debug criteria to be reported. The keyword events omits reports of any Data or Receive Ready (RR) flow control packets; the normal flow of Data and RR packets is commonly large as well as less interesting to the user, so event reporting can significantly decrease the processor load induced by debug reporting.
The debug x25 interface command is useful for diagnosing problems encountered with a single X.25 or CMNS host or virtual circuit.
Because no interface is specified by the debug x25 vc command, traffic on any virtual circuit that has the specified number is reported.
Virtual circuit zero (vc 0) cannot be specified. It is used for X.25 service messages, such as RESTART packets, not virtual circuit traffic. Service messages can be monitored only when no virtual circuit filter is used.
The debug x25 xot output allows you to restrict the debug output reporting to XOT traffic for one or both hosts or host/port combinations. Because each XOT virtual circuit uses a unique TCP connection, an XOT debug request that specifies both host addresses and ports will report traffic only for that virtual circuit. Also, you can restrict reporting to sessions initiated by the local or remote router by, respectively, specifying 1998 for the remote or local port. (XOT connections are received on port 1998.)
Use the debug x25 aodi command to display interface PPP events running over an X.25 session and to debug X.25 connections between a client and server configured for AO/DI.
Use the debug x25 annexg command to display interface Annex G events (X.25 over Frame Relay).
The following is sample output from the debug x25 annexg command (see Table 13 for field descriptions):
Router# debug x25 annexg X.25 over FR (Annex-G) debugging is on 03:25:30:Se0 DLCI 18:X.25 I R1 Call (17) 8 lci 1 03:25:30: From(7):2193330 To(8):21921818 03:25:30: Facilities:(0) 03:25:30: Call User Data (4):0x01000000 (pad) 03:25:30:Se0 DLCI 18:X.25 O R1 Call Confirm (5) 8 lci 1 03:25:30: From(0): To(0): 03:25:30: Facilities:(0) 03:25:30:annexg_restart_tx:sending pak to Serial0 03:25:30:annexg_restart_tx:sending pak to Serial0 03:25:30:annexg_restart_tx:sending pak to Serial0
The following is sample output from an X.25 Restart event, a Call setup, data exchange, and Clear. The first two lines describe a Restart service exchange.
Router# debug x25 Serial0: X.25 I R/Inactive Restart (5) 8 lci 0 Cause 7, Diag 0 (Network operational/No additional information) Serial0: X.25 O R3 Restart Confirm (3) 8 lci 0 Serial0: X.25 I P1 Call (15) 8 lci 1 From(6): 170091 To(6): 170090 Facilities: (0) Call User Data (4): 0xCC000000 (ip) Serial0: X.25 O P3 Call Confirm (3) 8 lci 1 Serial0: X.25 I D1 Data (103) 8 lci 1 PS 0 PR 0 Serial0: X.25 O D1 Data (103) 8 lci 1 PS 0 PR 1 Serial0: X.25 I P4 Clear (5) 8 lci 1 Cause 9, Diag 122 (Out of order/Maintenance action) Serial0: X.25 O P7 Clear Confirm (3) 8 lci 1
Table 13 describes significant fields shown in the display.
| Field | Description |
|---|---|
Serial0 | Interface on which the X.25 event occurred. |
DLCI 18 | Annex G DLCI number. |
X.25 | Type of event this message describes. |
I or O | Letter indicating whether the X.25 packet was input (I) or output (O) through the interface. |
R3 | State of the service or virtual circuit. Possible values follow:
See Annex B of the 1984 ITU-T X.25 Recommendation for more information on these states. |
Restart | The type of X.25 packet. Possible values follow: R Events
|
(5) | Number of bytes in the packet. |
8 | Modulo of the virtual circuit. Possible values are 8 or 128. |
lci 0 | Logical channel interface (VC) number. See Annex A of the X.25 Recommendation for information on virtual circuit assignment. |
Cause 7 | Code indicating the event that triggered the packet. The Cause field can only appear in entries for Clear, Reset, and Restart packets. Possible values for the cause field can vary, depending on the type of packet. Refer to the "X.25 Cause and Diagnostic Codes" appendix for an explanation of these codes. |
Diag 0 | Code providing an additional hint as to what, if anything, went wrong. The Diag field can only appear in entries for Clear, Diagnostic (as "error 0"), Reset and Restart packets. Refer to the "X.25 Cause and Diagnostic Codes" appendix for an explanation of these codes. |
(Network operational/No additional information) | The standard explanations of the Cause and Diagnostic codes (cause/diag). |
The following example shows a sequence of increasingly restrictive debug x25 commands:
Router# debug x25 X.25 packet debugging is on Router# debug x25 events X.25 special event debugging is on Router# debug x25 interface serial 0 X.25 packet debugging is on X.25 debug output restricted to interface Serial0 Router# debug x25 vc 1024 X.25 packet debugging is on X.25 debug output restricted to VC number 1024 Router# debug x25 interface serial 0 vc 1024 X.25 packet debugging is on X.25 debug output restricted to interface Serial0 X.25 debug output restricted to VC number 1024 Router# debug x25 interface serial 0 vc 1024 events X.25 special event debugging is on X.25 debug output restricted to interface serial 0 X.25 debug output restricted to VC number 1024
The following examples show the normal sequence of events for both the AO/DI client and server sides:
Router# debug x25 aodi PPP-X25: Virtual-Access1: Initiating AODI call request PPP-X25: Bringing UP X.25 AODI VC PPP-X25: AODI Client Call Confirm Event Received PPP-X25: Cloning interface for AODI is Di1 PPP-X25: Queuing AODI Client Map Event PPP-X25: Event:AODI Client Map PPP-X25: Created interface Vi2 for AODI service PPP-X25: Attaching primary link Vi2 to Di1 PPP-X25: Cloning Vi2 for AODI service using Di1 PPP-X25: Vi2: Setting the PPP call direction as OUT PPP-X25: Vi2: Setting vectors for RFC1598 operation on BRI3/0:0 VC 0 PPP-X25: Vi2: Setting the interface default bandwidth to 10 Kbps PPP-X25: Virtual-Access2: Initiating AODI call request PPP-X25: Bringing UP X.25 AODI VC PPP-X25: AODI Client Call Confirm Event Received
Router# debug x25 aodi PPP-X25: AODI Call Request Event Received PPP-X25: Event:AODI Incoming Call Request PPP-X25: Created interface Vi1 for AODI service PPP-X25: Attaching primary link Vi1 to Di1 PPP-X25: Cloning Vi1 for AODI service using Di1 PPP-X25: Vi1: Setting vectors for RFC1598 operation on BRI3/0:0 VC 1 PPP-X25: Vi1: Setting the interface default bandwidth to 10 Kbps PPP-X25: Binding X.25 VC 1 on BRI3/0:0 to Vi1
debug ppp bap
debug ppp bap negotiation
debug ppp multilink
debug ppp negotiation
Posted: Tue Mar 2 10:16:20 PST 1999
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