The X.25 Interface

The X.25 network interface connects a router to an X.25 packet-switched network. This document includes the following sections:

X.25 Overview

The X.25 Protocol Stack

Configuration Procedures

X.25 Commands

X.25 Overview

The X.25 software and hardware allow the router to communicate over a public X.25 network. The X.25 network interface complies with CCITT 1980 and 1984 specifications for X.25 interfaces by offering multiplexed channels and reliable end-to-end data transfer across a WAN.

Protocol Handling

The X.25 interface provides both physical and logical access to remote X.25 hosts (routers). X.25 virtual circuits are either pre-established PVCs (Permanent Virtual Circuits) or dynamically set up SVCs (Switched Virtual Circuits) to remote destinations.

Permanent Virtual Circuits (PVCs). Permanent channels that remain connected after X.25 restarts. Because they are always present, these channels are similar to leased telephone lines. PVCs are suitable for high-volume data transfer and predictable protocol-specific traffic, such as routing updates.
Switched Virtual Circuits (SVCs). Non-permanent channels that require Call Setup and Call Clearing. The temporary status of the SVC channel is similar to an ordinary telephone call: a connection is established, data is transferred, and the connection is closed. SVCs are suitable for a low to medium volume of data transfer and bursts of protocol specific traffic, like error correction.

Each X.25 interface can have up to 227 virtual circuits in any combination of PVCs or SVCs.

If the destination protocol address maps a PVC or an existing SVC to the same X.25 destination for which the queue or window is not full, the packet is encapsulated into an X.25 data packet and forwarded to the X.25 network.

If there is no open virtual circuit and the router has not exceeded the virtual circuit limits, the router places an X.25 call to the matching X.121 network address. Subsequent packets to the same destination are queued while waiting for completion of the X.25 call process. When the call is complete, the router forwards all queued protocol packets to the network as X.25 data packets.

Configurable Parameters

The following factors control the number of SVCs the router originates:

The maximum number of calls out. (See the set calls-out command.)
The default window size. (See the add protocol command.)
The maximum number of virtual circuits (any combination of permanent or switched) directed to a protocol destination is 227.

The above limits prevent a flurry or burst of protocol traffic from consuming router or network resources.

As the X.25 software queues protocol traffic while awaiting X.25 call completion, the software initially establishes only one circuit to a destination. Once that circuit is established, additional circuits are added to the same destination as needed. This is governed by both the configured window-size and calls-out parameters, and by the 4 or 10 circuit limit given to a protocol destination. For example, if calls-out is set to 4 or greater and the protocol window-size is set to the default of 7, there is a potential of (window-size * 4-circuit limit) 28 outbound protocol packets queued toward the destination.

The router closes SVCs after a configurable period of idleness. The protocol idle-time configuration overrides the global setting, allowing flexibility on a per protocol basis. Additional circuits established during a burst of protocol traffic eventually clear, and protocol traffic settles down and passes on the earlier created circuits.

The idle timeout can greatly affect applications that lack peer-to-peer keep alive mechanisms. If protocol traffic is sparse, change the idle period to a reasonable time period to avoid unnecessary call clearing, but not so long as to hang unused circuits or to initiate a protocol time-out because of a lack of update messages. The default idle period is 30 seconds; a period of 90 seconds is a reasonable alternative.

Addressing

You must assign a unique X.121 network address to each X.25 network interface. Failure to set the network address prevents the X.25 interface from joining the attached network. When connecting to an X.25 switch this address must match the address of the switch configuration. When connecting to a public X.25 network, the owner of the X.25 network assigns this X.121 address to your router.

The remote DTE uses the X.121 address when establishing a call and the router uses the address to identify itself when routing calls. The remote DTE maps destination protocol addresses to X.121 call addresses. The source address of one DTE is the destination for another, thus facilitating the piggy backing of protocol return traffic on pre-established circuits. Configure the mapping between the destination protocol address and the destination DTE address using the X.25 add address configuration command. You can assign different protocol destination addresses to a single destination DTE address.

Mapping of the protocol to a X.121 call address is static, and you configure the mapping on a per protocol and a per network interface basis. The exception is DDN addresses (IP HostTableFormat Addresses), which you can configure as static permanent entries or dynamically instantiated parallel to the IP protocol packet send sequence. Dynamic translations of IP HTF addresses to X.121 addresses are not saved over router restarts and are not displayed via the list option in the configuration command.

Figure 1 shows how remote local area networks and internets connect over a public data network.

Figure 1 X.25 Remote Access

For IPX routing packets addressed to "all nodes," X.25 sends the packet to each destination it knows about for that protocol (configured with the add address command), opening SVCs as necessary.

The X.25 Protocol Stack

The X.25 protocol stack provides network access standards for layers that are similar to the first three layers of the Open Systems Interconnection (OSI) reference model. The X.25 protocol stack consists of the physical, frame, and packet layers. These three layers closely resemble the physical, data link, and network layers of the OSI model.

The Physical Layer

The X.25 interface's physical layer specifies the hardware interface between the Data Terminal Equipment (DTE) and the Data Circuit-terminating Equipment (DCE). The X.25 physical layer specifies a cable interface that connects a DTE, such as the router to a public data network via a DCE device, such as a modem or DSU/CSU. Typical physical layer connections are described below:

Though the router supports an X.25 DCE interface (Quad serial only), DTE is the normal mode of operation.

The X.25 software supports the following physical layer interfaces:

RS-232-C at speeds up to 19.2-Kbps
RS-449 at speeds up to 64-Kbps
V.35 at speeds up to 2-Mbps
X.21 at speeds up to 2-Mbps

To use the p4298-01 RS-232 or the p4298-02 RS-449 level converter with the X.25 interface, you must build a special modem cable and wire this cable as shown in Figure 2.

Figure 2 Wiring for p4298-01 Level Converter

The Frame Layer

The X.25 interface's frame/packet layer, like the connection based data link layer in the OSI model, handles error control as the data travels on the interface between the router and the public data network. This layer, provides certain X.25 DTEs with an interface to the internet. When transmitting data from the router to the network, the frame layer supports the link access procedure-balanced (LAP-B) protocol.

The Packet Layer

The X.25 interface's packet layer, like the network layer in the OSI model, establishes, manages and terminates end-to-end communications between local and remote hosts. The packet layer uses virtual circuit connections to establish communication between the router and a public data network with DCE capabilities. End-to-end communications issues include addressing, flow control, delivery confirmations, and interrupt signals.

X.25 software transfers packets using connection-oriented, or virtual circuit, packet switching. Virtual circuits transmit each packet sequentially, down a pre-established path. Virtual circuit connections are similar to placing a call over telephone facilities. Once the packet layer establishes a connection, the router can sequentially transmit data over the link.

Return traffic is usually directed on the same virtual circuit established from the source to the destination DTE, provided additional circuits are not open the same destination.

Configuration Procedures

This section outlines the minimal steps required to get X.25 up and running. For reference information on commands, see X.25 Commands.

Note: After you follow these steps, restart the router for configuration changes to take effect.

1. Set the data-link protocol for the serial interface to X.25. Enter list interfaces to see a list of the interfaces from which you can select.

Config> set data-link x25
Interface Number [0]? 1

2. Enter network followed by the number of the X.25 interface.

Config> network 1
X.25 User Configuration
X.25 Config>

3. Specify the network address by entering set address x.25-node-address.

The X.25 address is a unique X.121 address that is used during call establishment. You must specify an X.25 node address for each router interface. Failure to set the network address prevents the X.25 interface from joining the attached network.

4. Enter set equipment-type and specify whether the frame and packet levels act as DCE or DTE. The default is DTE.

5. For the RBX Series only, type set cable and specify one of the cable types: RS-232, V35, V36, or X21. You also need to choose DTE or DCE.

X.25 Config>set cable ?
RS-232
V35
V36
X21
X.25 Config>set cable V35 ?
DTE
DCE

6. Enter set clocking and choose internal, external, or mixed based on your router type.

X.25 Config>set clocking ?
EXTERNAL
INTERNAL
MIXED
X.25 Config>set clocking external

You must use SVCs or PVCs. You may use both. If you are going to use SVCs, continue with step 1, if not, skip to step 3.

1. Enter set svc and define the lowest and highest SVCs that you are using.

There are three types of SVCs: -two-way, -inbound, and -outbound. The default is svc low-two-way = 1 and svc high-two-way = 64. All other SVC types default to 0.

Keep the following restrictions in mind when defining PVCs and SVCs. If there is any overlapping, you will get an ELS message.

You must define the range of PVCs starting from 1 to n.
SVCs may follow the defined PVCs. If SVCs follow PVCs, they must not overlap.
The total number of SVC channel numbers and PVC channel numbers cannot exceed 239.
You can define the virtual circuit channel numbers in the range of 1 to 4095.

2. To add the protocols that run over the X.25 interface, enter add protocol protocol_name. If you are going to configure other protocols, do it now.

The software prompts you for window size, default packet size, maximum packet size, circuit idle time, and max VCs.

Note: At this point, you have set up your SVCs. If you must also use PVCs, continue with step 3, if not, skip to step 5.

3. Enter set pvc and define the lowest and highest PVCs that you are using.

4. To define PVCs individually, enter add pvc. The packet channel numbers under add pvc must be the same.

5. To add an address translation for each protocol's destination address reachable over this interface, enter add address protocol_name.

Setting the National Personality

Each public data network, such as the GTE Telenet or the DDN Defense Data Network, has its own standard configuration. The term National Personality specifies a group of variables that define a public data network's characteristics. The configuration information in the National Personality provides the router with control information for packets being transferred over the link. The National Personality option defines 28 default parameters for each public data network.

To see the configuration values in your X.25 National Personality, enter list detailed at the X.25 config> prompt. To configure each public data network connected to the router, enter set national personality at the X.25 config> prompt.

Note: The National Personality is a generalized template for network configuration. If necessary, you can individually configure each frame and packet-layer parameter.

X.25 Commands

This section describes the X.25 commands.

Not all parameters apply to all router platforms. Press Space twice after you type a command to display the available parameters for each command for your router. Enter help for information about using the command line interface.

[C] means the command is available at the X.25 config> prompt.

[M] means the command is available at the X.25> prompt.

Table 1 X.25 Commands

Command Function

Add [C] Adds an address translation, a protocol encapsulation, or a PVC definition.

Change [C] Changes an address translation, a protocol encapsulation, or a PVC definition.

Delete [C] Removes an address translation, a protocol encapsulation, or a PVC definition.

Disable [C] Disables interface-resets, incoming-calls-barred feature, outgoing-calls-barred feature, or dynamic DDN address translations.

Enable [C] Enables interface-resets, incoming-calls-barred feature, outgoing-calls-barred feature, or dynamic DDN address translations.

Exit [C] [M] Returns to the previous prompt.

List [C] [M] At the configuration prompt, shows the X.25 configuration.
At the monitoring prompt, shows individual PVC or SVC statistics and general information.

National Disable [C] Disables features defined by the National Personality configuration.

National Enable [C] Enables features defined by the National Personality configuration.

National Restore [C] Restores the National Personality configuration to its default values.

National Set [C] Sets parameters defined by the National Personality configuration.

Parameters [M] Displays the current parameters for any level of the X.25 configuration.

Set [C] Sets the local and DDN X.25 node addresses, window size for frame and packet levels, identifies the National Personality, the MTU, and the maximum number of calls. Defines the PVC and SVC channel ranges, the number of seconds that a switched circuit can be idle before it is cleared, and specifies whether the frame and packet levels act as DCE or DTE.

Statistics [M] Displays the current statistics for any level of the X.25 configuration.

Table 1 X.25 Commands
Command	Function
Add [C]	Adds an address translation, a protocol encapsulation, or a PVC definition.
Change [C]	Changes an address translation, a protocol encapsulation, or a PVC definition.
Delete [C]	Removes an address translation, a protocol encapsulation, or a PVC definition.
Disable [C]	Disables interface-resets, incoming-calls-barred feature, outgoing-calls-barred feature, or dynamic DDN address translations.
Enable [C]	Enables interface-resets, incoming-calls-barred feature, outgoing-calls-barred feature, or dynamic DDN address translations.
Exit [C] [M]	Returns to the previous prompt.
List [C] [M]	At the configuration prompt, shows the X.25 configuration. At the monitoring prompt, shows individual PVC or SVC statistics and general information.
National Disable [C]	Disables features defined by the National Personality configuration.
National Enable [C]	Enables features defined by the National Personality configuration.
National Restore [C]	Restores the National Personality configuration to its default values.
National Set [C]	Sets parameters defined by the National Personality configuration.
Parameters [M]	Displays the current parameters for any level of the X.25 configuration.
Set [C]	Sets the local and DDN X.25 node addresses, window size for frame and packet levels, identifies the National Personality, the MTU, and the maximum number of calls. Defines the PVC and SVC channel ranges, the number of seconds that a switched circuit can be idle before it is cleared, and specifies whether the frame and packet levels act as DCE or DTE.
Statistics [M]	Displays the current statistics for any level of the X.25 configuration.

Add [C]

Adds an X.25 address, a DDN X.25 htf-address, a protocol configuration, or a PVC definition.

Syntax: add

address
htf-address
protocol
pvc

address

Adds a PDN (Public Data Network) X.25 address translation for a protocol the router supports. The prompts that appear depend on the protocol address you are adding (see following examples). The protocol address and X.25 address you enter represent the protocol and X.25 address at the remote end of the X.25 link. Use the set address command to set the local X.25 address.

Example: add address

IP example:

Protocol [IP]? IP
IP Address [0.0.0.0]? 128.185.1.2
X.25 Address []? 1234590

IPX example:

Protocol [IP]? IPX
CUD Field Usage (Standard or Proprietary) 
IPX Host Number (in hex) []?
X.25 Address []?


Protocol	Protocol type of the address mapping: IP or IPX. The default is IP.
IP Address	Destination's IP address.
IPX/XNS Host Number	The IPX or XNS host number of the destination.
CUD Field Usage	For IPX to X.25 address mapping only. It determines how the Call User Data (CUD) field is filled in when call request packets are received for IPX. Standard indicates that the usage is the protocol identification specified in RFC 1356. If you enter an invalid choice, the software defaults to Proteon Proprietary.
X.25 Address	The Public Data Network (PDN) interface's X.25 address that connects to the router. The maximum address length is 15 digits.

htf-address

Adds a DDN (Defense Data Network) X.25 address translation.

Example: add htf-address

Protocol [IP]?
Convert HTF address [0.0.0.0}?


Protocol	The protocol that you are running over the X.25 interface. DDN supports IP only.
Convert HTF address	Converts the entered IP address to DDN Host Table Format. Also refer to ddn-address-translations in the Enable/Disable commands section.

protocol

Enables a protocol encapsulation and defines associated parameters.

Example: add protocol

Protocol [IP]
Window Size [2]
Default Packet Size [128]
Maximum Packet Size [256]
Circuit Idle Time [30]
Maximum SVCs [4]


Protocol	Protocol whose encapsulation parameters you want to add: IP or IPX. The default is IP.
Window Size	The number of packets that can be outstanding before an adjacent circuit is established to the same destination. The default is 2.
Default Packet Size	The default requested packet size for SVCs. This value must be less than or equal to the maximum packet sized specified with the national set packet-size command. For RBX Series, CNX 500, CNX 600, and DNX 350 routers, the maximum is 4096 bytes. For the DNX 300, the maximum is 2048 bytes. The default is 128 bytes.
Maximum Packet Size	The maximum negotiated packet size for SVCs. This value must be less than or equal to the maximum packet size specified with the national set packet-size command. For RBX Series, CNX 500, CNX 600, and DNX 350 routers, the maximum is 4096 bytes. For the DNX 300, the maximum is 2048 bytes. The default is 256.
Circuit Idle Time	The number of seconds that an SVC can be idle before it is cleared. The range is 0 to 65365. The default is 30 seconds. A 0 (zero) specifies that the circuit is never cleared.
Maximum SVCs	The maximum number of SVCs that are open to a destination for a protocol. Use this parameter where parallel paths can result in misordering of forwarder packets. Setting this parameter to the proper number helps to eliminate this problem (at the cost of lower bandwidth). The default is 4.

pvc

Adds PVC, window size, and packet size definitions.

Example: add pvc

Protocol [IP]? IP
Packet Channel [1]?
Destination X.25 Address[]?
Window Size [2]?
Packet Size [128]?


Protocol	Specifies which protocol's encapsulation parameters you want to modify. The default is IP.
Packet Channel	Circuit number of the PVC. Note: If there is an X.25 link between two nodes, the packet channels must match.
Destination X.25 Address	X.25 address of the PVCs destination.
Window Size	Packets that can be outstanding before an acknowledgment is sent. The default is 2.
Packet Size	Bytes in the data portion of the packet. The default is 128 bytes. This value must be less than or equal to the maximum set by the national set packet-size command.

Change [C]

Modifies a PDN X.25 address, DDN X.25 address, protocol configuration, or a PVC definition.

Syntax: change

address
htf-address
protocol
pvc

address

Modifies a PDN X.25 address translation. The prompts that appear depend on the protocol.

Example: change address

IP example:

Protocol [IP]? IP
IP Address [0.0.0.0]?
X.25 Address [00000124040000]?

IPX example:

Protocol [IP]? IPX
CUD Field Usage (Proteon or Standard) [Proteon]?
IPX Host number (in hex) []?
X.25 Address [00000124040000]?


Protocol	Protocol type of the address mapping you want to change: IP or IPX. The default is IP.
IP address	Destination protocol interface's IP address.
CUD Field Usage	For IPX to X.25 address mapping only. It determines how the Call User Data field is filled in when the router receives call request packets for IPX. Standard indicates that the usage is the protocol identification specified in RFC 1356. If you enter an invalid choice, the software defaults to Proteon Proprietary.
X.25 address	The destination's new PDN X.25 address. The default is current PDN X.25 address.
IPX Host number	The IPX host number that you want to change.

htf-address

Changes a DDN X.25 address translation.

Example: change htf-address

Protocol [IP]
Change HTF address [0.0.0.0]?
New HTF address [10.4.0.124]?


Protocol	The protocol you are running over the X.25 interface. DDN supports IP only.
Change HTF address	The current Host Table Format (HTF) address that you want to change.
New HTF address	The new HTF address. The default is current HTF address.

protocol

Changes a protocol configuration definition.

Example: change protocol

Protocol [IP]
Window Size [2]
Default Packet Size [128]
Maximum Packet Size [256]
Circuit Idle Time [30]
Max VCs [6]


Protocol	Specifies which protocol's encapsulation parameters you want to change. The default is IP.
Window Size	Number of packets that can be outstanding before an adjacent circuit is established to the same destination.
Default Packet Size	Default requested packet size for SVCs. This value must be less than or equal to the maximum packet size specified with the national set packet-size command. For the CNX 500 and 600 routers using the Twin/Quad serial interface, the maximum is 4096 bytes. The DNX 300 has a maximum of 2048 bytes. The DNX 350 and RBX Series have a maximum of 4096 bytes.
Maximum Packet Size	Maximum negotiated packet size for SVCs. This value must be less than or equal to the maximum packet sized specified with the national set packet-size command. For CNX 500 and 600 routers using the Twin/Quad serial interface, the maximum is 4096 bytes. The DNX 300 has a maximum of 2048 bytes. The DNX 350 and RBX Series have a maximum of 4096 bytes.
Circuit Idle Time	Number of seconds that a circuit can be idle before it is cleared. The range is 0 (zero) to 65365. The default is the currently defined circuit idle time in seconds. A 0 specifies that the circuit is never cleared.
Maximum SVCs	Maximum number of SVCs that are open to a destination for a protocol. Use this parameter where parallel paths can result in misordering of forwarder packets. Setting this parameter to the proper number helps to eliminate this problem (at the cost of lower bandwidth).

pvc

Changes PVC, window size, and packet size definitions.

Example: change pvc

Protocol [IP]? IP
Packet Channel [1]?
Destination X.25 Address[]?
Window Size [2]?
Packet Size [128]?


Protocol	Specifies which protocol's encapsulation parameters you want to change. The default is IP.
Packet Channel	Circuit number of the PVC. The default is 1.
Destination X.25 Address	Address of the PVCs destination.
Window Size	Number of packets that can be outstanding before an acknowledgment is sent.
Packet Size	Number of bytes in the data portion of the packet. The default is 128 bytes. Enter a value equal to or less than the maximum set by the national set packet-size command.

Delete [C]

Deletes an X.25 address translation, a protocol configuration definition, or a PVC definition.

Syntax: delete

address
protocol
pvc

address

Deletes an X.25 address translation.

Example: delete address

IP example:

Protocol [IP]?
IP Address [0.0.0.0]?

IPX example:

Protocol [IP]?
IPX Host Number (in hex) [2]?


Protocol	The protocol type of the address mapping you are deleting. The default is IP.
IP Address	The destination protocol interface's IP address.
IPX Host Number	The IPX host number.

protocol prot-type

Deletes a protocol encapsulation configuration. Prot-type is the name or number of the protocol encapsulation that you created using the add protocol command.

Example: delete protocol ipx

pvc

Deletes a PVC definition.

Example: delete pvc

Protocol [IP]?
Packet Channel [1]?
Destination X.25 Address []?


Protocol	The protocol that you are running over the X.25 interface. DDN supports IP only.
Packet Channel	The circuit number of the PVC.
Destination X.25 Address	The address of the PVCs destination.

Disable [C]

Disables DDN address translations, interface resets as part of network certification, the incoming-calls-barred or the outgoing-calls-barred features.

Syntax: disable

ddn-address-translations
interface-resets
incoming-calls-barred
outgoing-calls-barred

Enable [C]

Enables DDN address translations, interface resets, the incoming-calls-barred or the outgoing-calls-barred features.

Syntax: enable

ddn-address-translations
interface-resets
incoming-calls-barred
outgoing-calls-barred

ddn-address-translations

Specifies that the DDN host table format (IP) addresses are dynamically converted to X.121 call addresses. The default is disabled.

Example: enable ddn-address-translations

interface-resets

Specifies that either the router or the network interface can initiate the packet-layer restarts and the frame layer link establishment. Use this feature during normal operation. The default is enabled.

Example: enable interface-resets

incoming-calls-barred

Specifies that the router does not accept incoming calls. The default is enabled.

Example: enable incoming-calls-barred

outgoing-calls-barred

Specifies that the router does not allow outgoing calls. The default is enabled.

Example: enable outgoing-calls-barred

Exit [C] [M]

Returns to the previous prompt.

Syntax: exit

Example: exit

List [C] [M]

Displays the current configuration for the specified parameter.

List [C]

Syntax: list

addresses
all
detailed
protocols
pvc
summary

addresses

Lists all the X.25 address translations.

Example: list addresses

X.25 address translation configuration

IF# Prot # Protocol X.25 address
1 0 10.1.2.3 1238765742
1 4 1.10 9910
1 7 10 12389 CUD Field =Proteon


IF#	The current interface number. You accessed this at the `Config>` prompt using the net number command. All addresses listed belong to this network.
Prot#	The identification of the protocol that this mapping is defined.
Protocol	Destination address of the protocol.
X.25 address	Protocol X.25 address corresponding to that protocol address.
	CUD Field. This field is for IPX to X.25 address mapping only. It determines how the Call User Data field is filled in when call request packets are received for IPX. The CUD Field can be either Standard or Proteon. Standard indicates that the usage is the protocol identification specified in RFC 1356.

all

Lists all the X.25 addresses, National Personality parameters, all defined protocols and their values, and all defined PVC's.

Example: list all

X.25 Configuration Summary

Node Address: <none>
Max Calls Out: 4 Inter-Frame Delay: 1
Speed: 0 Clocking: External
MTU: 1500 Cable: V.35 DTE
Default Window: 2 SVC idle: 30 seconds

National Personality: GTE Telenet (DTE)
PVC low: 0 high: 0
Inbound low: 0 high: 0
Two-Way low: 1 high: 64
Outbound low: 0 high: 0
Throughput Class in bps Inbound: 2400
Throughput Class in bps Outbound: 2400

X.25 National Personality Configuration

Follow CCITT: on OSI 1984: on OSI 1988:off Clear w/diag: on Reset w/diag: on Restart w/diag: on Request Reverse Charges: on Accept Reverse Charges: on
Allow Packet Restarts: on Suppress Calling Addresses:off
Suppress Cause Fields: on Suppress Frame Idle RRs: off
Frame Extended seq mode: off Packet Extended seq mode: off
Use Multi-link Addresses:off Disable Interface Resets: off
Incoming Calls Barred: off Outgoing Calls Barred: off
Throughput Negotiation: on Flow Control Negotiation: on
DDN Address Translation: off
Call Request Timer: 20 decaseconds
Clear Request Timer: 18 decaseconds (1 retries)
Reset Request Timer: 18 decaseconds (1 retries)
Restart Request Timer: 18 decaseconds (1 retries)
T1 Timer: 4.00 seconds N2 timeouts: 20
T2 Timer: 2.00 seconds DP Timer: 500 milliseconds
Standard Version: 1984 Network Type: CCITT
Disconnect Procedure: passive
Window Size Frame: 7 Packet: 2
Packet Size Default: 128 Maximum: 256

X.25 protocol configuration

No protocols defined
X.25 PVC configuration
No PVCs defined

X.25 address translation configuration
No address translations defined

detailed

Lists the current settings of all the parameters that the national set command modifies. For descriptions of the screen display, see the national set command described later in this chapter.

Example: list detailed

X.25 National Personality Configuration

Follow CCITT: on OSI 1984: on OSI 1988: off
Clear w/diag: on Reset w/diag: on Restart w/diag: on
Request Reverse Charges: on Accept Reverse Charges: on
Allow Packet Restarts: on Suppress Calling Addresses: off
Suppress Cause Fields: on Suppress Frame Idle RRs: off
FrameExtended seq mode: off PacketExtended seq mode: off
UseMulti-linkAddresses: off Disable Interface Resets: off
Incoming Calls Barred: off Outgoing Calls Barred: off
Throughput Negotiation: on Flow Control Negotiation: on
DDN Address Translation: off
Call Request Timer: 20 decaseconds
Clear Request Timer: 18 decaseconds (1 retries)
Reset Request Timer: 18 decaseconds (1 retries)
Restart Request Timer: 18 decaseconds (1 retries)
T1 Timer: 4.00 seconds N2 timeouts: 20
T2 Timer: 2.00 seconds DP Timer: 500 milliseconds
Standard Version: 1984 Network Type: CCITT
Disconnect Procedure: passive
Window Size Frame: 7 Packet: 2
Packet Size Default: 128 Maximum: 256

protocols

Lists all the defined protocol configurations.

Example: list protocols

X.25 protocol configuration

Protocol Window Packet-Size Max
Number Size Default Maximum Time VCs
0 4 128 256 10 6
5 2 128 256 30 6


Protocol Number	Encapsulation parameters for that protocol: IP=0, IPX=7.
Window Size	Packets that can be outstanding before an acknowledgment is sent.
Packet-Size	Default and maximum packet sizes configured for the protocol on the router.
Idle Time	Number of seconds that a circuit can be idle before it is cleared. The range is 0 (zero) to 65365. A 0 specifies that the circuit is never cleared.
Maximum VCs	Maximum number of VCs that can be opened to a destination for a protocol. Note: This parameter is supported in the DNX and CNX Quad and CNX Twin serial configurations only.

pvc

Lists all the defined PVCs.

Example: list pvc

X.25 PVC configuration

Prtcl X.25 Address Window Pkt_len Pkt_chan
0 8383838383 4 1024 3


Prtcl	Identifies the protocol running over this PVC: IP=0, IPX=7, XNS=5, or DN=4.
X.25 Address	Destination X.25 address.
Window	Window size of the PVC.
Pkt_len	Maximum length of a packet transmitted over the PVC.
Pkt_chan	Circuit number (Packet Channel) of the PVC.

summary

Lists all the values established by the set and enable commands. The following example is of an RBX Series router.

Example: list summary

X.25 Configuration Summary

Node Address: 12345
Max Calls Out: 4 Inter-Frame Delay: 1
Speed: 0 Clocking: External
MTU: 1500 Cable: V.35 DTE
Default Window: 2 SVC idle: 30 seconds
National Personality: GTE Telenet (DTE)
PVC low: 0 high: 0
Inbound low: 0 high: 0
Two-Way low: 1 high: 64
Outbound low: 0 high: 0
Throughput Class in bps Inbound: 2400
Throughput Class in bps Outbound: 2400


Node Address	Local X.25 interface address (x.25-node-addr).
Max Calls Out	Maximum number of SVC's initiated by the router to a given destination for the total of all the protocols. The range is 1 to 227.
Inter-Frame Delay	Minimum number of flags set to be transmitted between frames. This parameter is supported for the DNX Quad serial, CNX Quad/Twin routers, and the RBX Series.
Speed	Speed of the transmit and receive clock lines, using the set speed command.
Clocking	Configured method of clocking as Internal or External.
MTU	Frame size set with the set mtu command.
Cable	Displays the type of cable set using the set cable command. (RBX Series only)
Default Window	Window size assumed for the packet layer. In the absence of any facilities in the SVC call setup, this is the assured value.
SVC idle	Number of seconds that a switched circuit can be idle before it is cleared. The range is 1 to 255.
National Personality	GTE-Telenet or DDN National Personality. GTE-Telenet is the default setting.
PVC (low, high)	Lowest to highest PVC channel numbers. Zero indicates no PVCs. The range is 0 through 4095.
Inbound (low, high)	Lowest to highest inbound-only SVC channel numbers. The default is 0; therefore, by default, there are no inbound-only SVCs. The range is 0 through 4095.
Two-way (low, high)	Lowest to highest 2-way SVC channel numbers. The default is 1 for the low parameter and 64 for the high parameter. By default, there are 64 two-way SVCs. The range is 0 through 4095.
Outbound (low, high)	Lowest to highest outbound-only SVC channel numbers. The default is 0; therefore, by default, there are no outbound-only SVCs. The range is 0 through 4095.
Throughput Class in bps (inbound, outbound)	Default throughput capacity (in bits per second) for inbound and outbound traffic.

List [M]

Displays the current active PVCs and SVCs.

Syntax: list

pvcs
svcs

pvc

Displays the configured permanent virtual circuits.

Example: list pvcs

svc

Displays the active switched virtual circuits.

Example: list svcs

HCN/ Destination Originate Transmits Protocol Totals
State Address Call Queued Encapsulated Xmts Rcvs Resets

13 D 898280077113 YES 0 IP 8943 261
1 20 D 898280077114 NO 0 IP 943 43
0 40 D 898280077115 YES 0 DN 567 104
0 42 P 898280077116 YES 6 IP 0 0
0 23 C 898280077117 YES 0 IP 3054 110 0

D - Data Transfer P - Call Progressing
C - Call Clearing

National Disable [C]

Disables a feature defined by the National Personality configuration.

Syntax: national disable

accept-reverse-charges
ccitt
clear-w/diag
flow-control-negotiation
multi-link-addresses
osi-84
osi-88
packet-layer-restarts
request-reverse-charges
reset-w/diag
restart-w/diag
suppress-calling-addresses
suppress-idle-frame-rr
suppress-non-zero-cause
throughput-class-negotiation

accept-reverse-charges

Disables the accepting of reverse charges for calls during call establishment. This option is not available for DDN.

Example: national disable accept-reverse-charges

ccitt

Disables the use of the CCITT convention, rather than ISO convention, that is followed for timer retry expiration. CCITT acts as if the confirmation packet for the restart or clear requests had arrived. ISO leaves the request unconfirmed.

Example: national disable ccitt

clear-w/diag

Does not allow clear request packets to include the diagnostic field.

Example: national disable clear-w/diag

flow-control-negotiation

Disables negotiation of packet and window size during call setup of SVCs.

Example: national disable flow-control-negotiation

multi-link-addresses

Sets the frame level addresses back to A (03) and B (01).

Example: national disable multi-link-addresses

osi-84

Disables CCITT OSI facilities as defined by the 1984 standard.

Example: national disable osi-84

osi-88

Disables CCITT OSI facilities as defined by the 1988 standard.

Example: national disable osi-88

packet-layer-restarts

Disables the packet layer from sending a start packet when the router restarts. The default is on. Disable this feature only if the switch you are connecting to requires that this be disabled.

Note: If this feature is disabled on both sides of the line, the line does not come up. If this feature is disabled on one side of the line, the line should still come up. Example: national disable packet-layer-restarts

request-reverse-charges

Disables the requesting of reverse charges for all outgoing calls.

Example: national disable request-reverse-charges

reset-w/diag

Disables the inclusion of diagnostic fields in restart request packets.

Example: national disable reset-w/diag

restart-w/diag

Disables the inclusion of diagnostic fields in restart request packets.

Example: national disable restart-w/diag

suppress-calling-addresses

Disables the suppression of the source address in call packets.

Example: national disable suppress-calling-addresses

suppress-idle-frame-rr

Enables the sending of idle receiver ready frame layer frames.

Example: national disable suppress-idle-frame-rr

suppress-non-zero-cause

Disables the inclusion of non-zero values in the packet-layer cause fields.

Example: national disable suppress-non-zero-cause

throughput-class-negotiation

Disables the negotiation of through-put class during call setup of SVCs.

Example: national disable throughput-class-negotiation

National Enable [C]

Enables features defined in the National Personality configuration.

Syntax: national enable

accept-reverse-charges
ccitt
clear-w/diag
flow-control-negotiation
multi-link-addresses
osi-84
osi-88
packet-layer-restarts
request-reverse-charges
reset-w/diag
restart-w/diag
suppress-calling-addresses
suppress-idle-frame-rr
suppress-non-zero-cause
throughput-class-negotiation

accept-reverse-charges

Accepts reverse charge calls during call establishment. This option is not available for DDN.

Example: national enable accept-reverse-charges

ccitt

Specifies that the CCITT convention, rather than ISO convention, is followed for timer retry expiration. CCITT acts as if the confirmation packet for the restart or clear requests had arrived. ISO leaves the request unconfirmed.

Example: national enable ccitt

clear-w/diag

Allows clear request packets to include the diagnostic field.

Example: national enable clear-w/diag

flow-control-negotiation

Enables the negotiation of packet and window size during call setup of SVCs.

Example: national enable flow-control-negotiation

multi-link-addresses

Allows the frame level to use addresses C (0F) and D (07) rather than A (03) and B (01).

Example: national enable multi-link-addresses

osi-84

Allows CCITT OSI facilities defined by the 1984 standard.

Example: national enable osi-84

osi-88

Allows CCITT OSI facilities defined by the 1988 standard.

Example: national enable osi-88

packet-layer-restarts

Specifies that the packet layer sends a restart packet when the router restarts.

Example: national enable packet-layer-restarts

request-reverse-charges

Requests reverse charges for all outgoing calls.

Example: national enable request-reverse-charges

reset-w/diag

Allows reset request packets to include the diagnostic field.

Example: national enable reset-w/diag

restart-w/diag

Allows restart request packets to include the diagnostic field.

Example: national enable restart-w/diag

suppress-calling-address

Suppresses the source address in call packets.

Example: national enable suppresses-calling-addresses

suppress-idle-frame-rr

Suppresses the sending of idle receiver ready frame layer frames.

Example: national enable suppress-idle-frame-rr

suppress-non-zero-cause

Suppresses packet-layer cause fields.

Example: national enable suppress-non-zero-cause

throughput-class-negotiation

Enables the registration of throughput class.

Example: national enable throughput-class-negotiation

National Restore [C]

Restores one or all of the default values made to the National Personality configuration with the national set, national enable, or national disable commands.

Syntax: national restore

all
accept-reverse-charges
call-req
ccitt
clear-req
clear-w/diag
disconnect-procedure
dp-timer
flow-control-negotiation
frame-window-size
multi-link-addresses
network-type
n2-timeouts
osi-84
osi-88
packet-size
packet-layer-restarts
request-reverse-charges
reset
reset-w/diag
restart
standard-version
suppress-calling-addresses
suppress-idle-frame-rr
suppress-non-zero-cause
throughput-class-negotiation
t1-timer
t2-timer

all

Restores all the default values to the National Personality configuration currently set (GTE-Telnet or DDN).

Example: national restore all

accept-reverse-charges

Restores to the National Personality default the accept-reverse-charges feature for calls during call establishment. For GTE, default is on. For DDN, default is off.

Example: national restore accept-reverse-charges

call-req

Resets to the National Personality default the number of ten second intervals permitted before clearing an unaccepted call.

Example: national restore call-req

ccitt

Restores to the National Personality default the feature that specifies that the CCITT convention, rather than ISO convention, is followed for timer retry expiration. CCITT acts as if the confirmation packet for the restart or clear requests had arrived. ISO leaves the request unconfirmed.

Example: national restore ccitt

clear-req retries or timer

Resets to the National Personality default the number of clear request transmissions (retries) or the number of ten second intervals (timer) to wait before retransmitting .

Example: national restore clear-req retries

clear-w/diag

Restores to the National Personality default the feature that allows clear request packets to include the diagnostic field.

Example: national restore clear-w/diag

disconnect-procedure passive or active

Restores to the National Personality default the disconnect procedure to use when disconnecting. Passive is the default. It specifies that there are no DISC frames used when disconnecting. Active specifies that there are DISC frames used when disconnecting.

Example: national restore disconnect-procedure passive

dp-timer

Restores to the National Personality default the DP-timer that specifies the number of milliseconds that the frame level remains in a disconnected state. Zero indicates immediate transition from disconnected phase to link setup state.

Example: national restore DP-timer

flow-control-negotiation

Restores to the National Personality default the feature that determines the frame's packet size and window size; suitable for call set-up negotiation.

Example: national restore flow-control- negotiation

frame-window-size

Restores to the National Personality default the default number of frames.

Example: national restore frame-window-size

multi-link-addresses

Restores to the National Personality default the default value for frame layer addressing.

Example: national restore multi-link-addresses

network-type CCITT or DDN

Restores to the National Personality default convention. CCITT pecifies the Consultative Committee on International Telephone and Telegraph (CCITT) convention. (GTE - Telenet default) DDN specifies the DoD Defense Data Network (DDN) convention. (DDN default)

Example: national restore network-type CCITT

n2-timeouts

Restores the National Personality default value for the number of times the T1 timer can expire before a state change.

Example: national restore n2-timeouts

osi-84

Restores to the National Personality default setting for CCITT OSI facilities defined by the 1984 standard.

Example: national restore osi-84

osi-88

Restores to the National Personality default setting for CCITT OSI facilities defined by the 1988 standard.

Example: national restore osi-88

packet-size default or max or window

Restores to the National Personality default values for these packet layer parameters.

Example: national restore packet-size default Default Restores the number of bytes in the data portion of the packet to 128. Max Restores the maximum number of bytes in the data portion of the packet to 256. Window Restores the number of outstanding I-frames permitted before acknowledgement is required to 2.

Default	Restores the number of bytes in the data portion of the packet to 128.
Max	Restores the maximum number of bytes in the data portion of the packet to 256.
Window	Restores the number of outstanding I-frames permitted before acknowledgement is required to 2.

packet-layer-restarts

Restores to the National Personality the default value for packet-layer sending of restart packet when the router restarts.

Example: national restore packet-layer-restarts

request-reverse-charges

Restores to the National Personality the default value for reverse charges request for all outgoing calls. For GTE, the default is on. For DDN, the default is off.

Example: national restore request-reverse-charges

reset retries or timer

Restores to the National Personality default value for the number of reset retransmissions.

Example: national restore reset retries Retries Number of reset request transmissions permitted before the call is cleared. The value is restored to 1. Timer Number of ten second intervals to wait before retransmitting a reset request packet. The value is restored to 18 decaseconds.

Retries	Number of reset request transmissions permitted before the call is cleared. The value is restored to 1.
Timer	Number of ten second intervals to wait before retransmitting a reset request packet. The value is restored to 18 decaseconds.

reset-w/diag

Restores to the National Personality default feature that allows the reset request packet to include the diagnostic field.

Example: national restore reset-w/diag

restart retries

Restores to the National Personality default value for the number of restart request retransmissions. The value is restored to 1 retry.

Example: national restore restart retries

restart timer

Restores to the National Personality timeout value for the number of restart request transmissions. The value is restored to 18 decaseconds.

Example: national restore restart timer

standard-version v1980 or v1984 or v1988

Restores to the National Personality default OSI facilities settings.

Example: national restore standard-version

suppress-calling-address

Restores to the National Personality default setting that determines whether to enable the suppression of the source address in call packets.

Example: national restore suppress-calling-address

suppress-idle-frame-rr

Restores the default value for this National Personality and determines whether to suppress the sending idle receiver ready frame layer frames. The default is disabled.

Example: national restore suppress-idle-frame-rr

suppress-non-zero-cause

Restores the default value for this National Personality and determines whether to suppress of the packet-layer cause fields. The default is disabled.

Example: national restore suppress-non-zero-cause

throughput-class-negotiation

Restores the default state (enable/disabled) determined by National Personality whether to negotiate the throughput class on SVC setup. The default is enable.

Example: national restore throughput-class-negotiation

t1-timer

Restores the default value of 4.00 seconds for the frame retransmit time in hundredths of a second.

Example: national restore t1-timer

t2-timer

Restores the default value for the maximum number of seconds (in hundredths) to wait before acknowledging an I-frame. Setting the timer to 0.00 disables it. The range is 0.00 to 255.99. The default is 2.00.

Example: national restore t2-timer

National Set [C]

Sets one or all of the default values made to the National Personality configuration.

Syntax: national set

call-req
clear-req
disconnect-procedure
dp-timer
frame-window-size
network-type
n2-timeouts
packet-size
reset
restart
standard-version
t1-timer
t2-timer

call-req # of decaseconds

Number of ten-second intervals permitted before giving up on a call request and clearing it. Zero indicates an indefinite wait.

Example: national set call-req 10

clear-req retries or timer

Specifies the number of clear request retransmissions.


Retries	Number of clear request transmissions permitted before action is taken.
Timer	Number of ten-second intervals to wait before retransmitting a call request packet. A zero indicates an indefinite wait.

Example: national set clear-req retries

disconnect-procedure passive or active

The type of disconnect procedure to use when disconnecting. Passive specifies that DISC frames are not used when disconnecting. Active specifies that DISC frames are used when disconnecting.

Example: national set disconnect-procedure active

dp-timer # of milliseconds

The number of milliseconds that the frame level remains in a disconnected state. Zero indicates immediate transition from disconnected phase to link setup state.

Example: national set dp-timer 500

frame-window-size

The number of frames that can be outstanding before acknowledgement.

Example: national set frame-window-size

network-type CCITT or DDN

The type of network being supported. CCITT specifies the CCITT convention. DDN specifies the DDN convention.

Example: national set network-type ccitt

n2-timeouts # of timeouts

The number of times the T1 timer can expire before a state change.

Example: national set n2-timeouts 15

packet-size default or max or window

The size of the packet.

Example: national set packet-size default Default Number of bytes in the data portion of the packet. Options are 128, 256, 512, 1024, 2048, and 4096. Set this value less than or equal to the maximum size. This value is used when and if flow control negotiation is enabled. Default cannot be greater than max. Max Maximum number of bytes in the data portion of the packet. Options are 128, 256, 512, 1024, 2048, and 4096. Note: When using the DNX WAN, the default and max values cannot be greater than 2048. Quad serial interfaces allow a size of 4096. Window Number of outstanding I-frames permitted before acknowledgement is required. The range is 1 to 7. This value is used when and if flow control negotiation is enabled.

Default	Number of bytes in the data portion of the packet. Options are 128, 256, 512, 1024, 2048, and 4096. Set this value less than or equal to the maximum size. This value is used when and if flow control negotiation is enabled. Default cannot be greater than max.
Max	Maximum number of bytes in the data portion of the packet. Options are 128, 256, 512, 1024, 2048, and 4096.
	Note: When using the DNX WAN, the default and max values cannot be greater than 2048. Quad serial interfaces allow a size of 4096.
Window	Number of outstanding I-frames permitted before acknowledgement is required. The range is 1 to 7. This value is used when and if flow control negotiation is enabled.

reset retries or timer

Specifies the number of reset request retransmissions.

Example: national set reset timer

restart retries or timer

Specifies the number of restart request transmissions.

Example: national set restart retries Retries Number of reset request transmissions permitted before the call is cleared. The range is 0 to 255. Timer Number of ten-second intervals to wait before retransmitting a restart request packet. The range is 0 to 255. A zero indicates an indefinite wait.

Retries	Number of reset request transmissions permitted before the call is cleared. The range is 0 to 255.
Timer	Number of ten-second intervals to wait before retransmitting a restart request packet. The range is 0 to 255. A zero indicates an indefinite wait.

standard-version v1980 or v1984 or v1988

Determines some of the default settings. Options are v1980, v1984, and v1988.

Example: national set standard-version v1988

t1-timer # of seconds

The frame retransmit time in hundredths of a second. The range is 0.05 to 255.99. The default is 4.00 seconds.

Example: national set t1-timer 5.25

t2-timer # of seconds

The amount of time to delay before acknowledging an I-frame. This is an optimization parameter. Setting the timer to 0.00 disables it. The range is 0.00 to 255.99. The default is 2.00.

Example: national set t2-timer 10

Parameters [M]

Displays the parameters for any level of the X.25 configuration.

Syntax: parameters

all
frame
packet
physical

all

Displays the parameters for the packet, frame, and physical levels.

Example: parameters all

Physical Layer Parameters:        
  Interface Type      =   V.35  

Maximum Frame Size    = 1030  InterFrame Delay  =   0
Configured Speed      =    0  Clocking          =Internal
Protocol Enabled      =  YES  

Frame Layer Parameters:  

  Maximum Frame Size  = 262 Maximum Window Size  =     7
  Protocol Enabled    = YES Equipment Type       =   DTE
  T1 Retransmit Timer =   4 T2 Acknowledge Timer =     2
  N2 Retry Counter     =  20  Disconnect Procedure  =PASSIVE
  Disconnect Timer     = 500  Network Type          =   GTE  

  Protocol Options: Inhibit Idle RRs NO  MOD 128      NO
                    A/B Addressing  YES  Enable SARM  NO
Packet Layer Parameters:
  Default Packet Size = 128  Maximum Packet Size=    256
  Log 2 Packet size   =   2  Acknowledge Delay  =      0
  Layer Enabled       = YES Default Window Size =      2
  Lowest SVC          =   1  Highest SVC        =     64
  Lowest PVC          =   0  Highest PVC        =      0
  Clear Diagnostic    = YES  Reset Diagnostic   =    YES
  Restart Diagnostic  = YES  T21 (Call)         =     20
  T20 (Restart)       =  18  R20 (Retry)        =      1
  T22 (Reset)         =  18  R22 (Retry)        =      1
  T23 (Clear)         =  18  R23 (Retry)        =      1 

  Network Type        = GTE  Equipment Type     =    DTE

frame

Displays the parameters for the frame level.

Example: parameters frame

Frame Layer Parameters:

Maximum Frame Size = 262 Maximum Window Size = 7
Protocol Enabled = YES Equipment Type = DTE
T1 Retransmit Timer = 4 T2 Acknowledge Timer = 2
N2 Retry Counter = 20 Disconnect Procedure = PASSIVE
Disconnect Timer = 500 Network Type = GTE

Protocol Options: Inhibit Idle RRs NO MOD 128 NO
A/B Addressing YES Enable SARM NO

packet

Displays the parameters for the packet level.

Example: parameters packet

Packet Layer Parameters:
  Default Packet Size = 128  Maximum Packet Size =   256
  Log 2 Packet size   =   2  Acknowledge Delay  =      0
  Layer Enabled       = YES Default Window Size =      2
  Lowest SVC          =   1  Highest SVC        =     64
  Lowest PVC          =   0  Highest PVC        =      0
  Clear Diagnostic    = YES  Reset Diagnostic   =    YES
  Restart Diagnostic  = YES  T21 (Call)         =     20
  T20 (Restart)       = 18  R20 (Retry)         =      1
 
 T22 (Reset)          = 18  R22 (Retry)         =      1
  T23 (Clear)         = 18   R23 (Retry)        =      1

  Network Type        = GTE  Equipment Type     =    DTE

physical

Displays the parameters for the physical level. The information displayed varies depending on the hardware platform you are using.

Example: parameters physical

Physical Layer Parameters:
  Interface Type       =    RS-449

  Maximum Frame Size  =    1030      InterFrame Delay    =        0
  Configured Speed    =    0         Clocking            = External
  Protocol Enabled    =    YES

Set [C]

Configures local X.25 node addresses, maximum number of calls, frame and packet level window size, lowest to highest PVC and SVC channels, and the idle time for a switched circuit.

Syntax: set

address
cable
calls-out
clocking
default-window-size
equipment-type
htf-address
inter-frame-delay
mtu
national-personality
pvc
speed
svc
throughput-class
vc-idle

address X.25-node-addr

Sets the local X.25 interface address. To delete the local X.25 address, set the X.25 node address to 0, not to 00.

Example: set address

address? 8982800

cable type

Sets the type of cable for RBX Series only, as follows:

RS-232 DTE
RS-232 DCE
V35 DTE
V35 DCE
V36
X21
Note: If you are using an RS-449 cable, enter V36 as the cable type.

Example: set cable RS-232 DTE

calls-out value

Sets the maximum number of locally initiated simultaneously active SVCs. The range is 1 to 227. The default is 4.

Example: set calls-out 3

clocking external or internal or mixed

To connect to a modem or DSU, configure clocking as external. To connect directly to another DTE device, use a DCE cable and set the clocking to internal. If the modem provides the receive clock lines and expects the transmit clock line, use mixed (no mixed clocking on RBX Series).

For internal and mixed clocking, you must use the set speed command to configure a clock speed.

For external clocking, if you want line speed reporting, enter the external clock speed using the set speed command. You can display the line speed using the interface command at the + prompt or using SNMP.

Example: set clocking internal

default-window-size value

Sets the window size for the packet level that the router assigns if there is no window-size facility in the Call-Request-Packet. The National Personality packet modulus (PACKET-EXT-SEQ-MODE) determines the range. The default is 2.

Example: set default-window-size 3

equipment-type DCE or DTE

Specifies whether the frame and packet levels act as DCE or DTE. DTE is the default. This has no relation to the cable type in use.

Example: set equipment-type DCE

htf-address x.25-node-addr

Sets the local DDN X.25 address translation (x.25-node-addr). Set the X.25 node address to 0.0.0.0 to delete the local X.25 node address.

Example: set htf-address 11.42.0.137

inter-frame-delay value

Allows the insertion of a delay between transmitted packets. The purpose of this command is to slow the serial line so that it is compatible with slower serial devices at the other end. This parameter works as follows:

On DNX 350 and CNX Twin/Quad serial interfaces, this is a time delay measured in units of 5 microseconds. The range is 0 to 65535. Zero (0) causes no delay.
RBX Series requests from 0 to 15 extra flags between frames.

Example: set inter-frame-delay 1

mtu value

Sets the Maximum Transmit Unit (MTU) in bytes. This is the maximum packet size that is delivered to the X.25 interface for packetization and transmission over the serial line. The range is 576 to 4096. The default is 1500.

If you encounter packet re-assembly timeouts on the X.25 interface, you should determine what the minimum packet size is for all LAN or serial interfaces that lead to the end point, then calculate a more suitable X.25 MTU. You should not directly consider the actual X.25 packet size in this calculation because X.25 tends to use a smaller packet size. X.25 usually sends up to 7 packets at one time before waiting for an acknowledgement.

For example, with a network topology that includes a Token Ring LAN having a packet size of 4000, an X.25 serial line having a packet size of 128 with a window size of 7 and a bit rate of 9600 bps, and an Ethernet LAN with a packet size of 1500, you should probably set the X.25 MTU to 1500. That means that about 12 packets are sent over the X.25 interface. (MTU / X.25 packet size = number of X.25 packets to be sent)

When using an MTU of 4096, 32 packets must be sent over the X.25 interface. (4000 /128 = 31.25) In this case, packet re-assembly timeouts will probably occur if the X.25 modem speed is 9600 bps. Using an X.25 modem speed of 56 Kbps should solve this problem.

Example: set mtu 2048

national-personality GTE-Telenet or DDN

Sets the 28 default parameters for either GTE-Telenet or DDN National Personality. GTE-Telenet is the default setting.

Example: set national-personality DDN

pvc low/high value

Defines the lowest to the highest PVC channel number. Zero indicates no PVCs. The default for pvc low is 0 and the default for pvc high is 0. Therefore, by default there are no PVCs. These values set the boundaries of a PVC range. The values of boundaries can range between 0 and 4095, however, the actual range is limited by memory. For example, if you set pvc low to 1 and set pvc high to 4095, these are valid boundary ranges, but there is not enough memory to support this range.)

Example: set pvc low 40

Note: Values must not overlap values set for SVCs.

speed bits-per-second

For internal clocking, speed specifies the speed of the transmit and receive clock lines. For mixed clocking, speed applies to the transmit clock line only. For external clocking, speed provides line speed reporting via SNMP and the interface command at the + prompt.

Valid settings for each type of serial interface are:

Interface Valid Setting

CNX Twin
300 to 6250000

DNX 350
300 to 8000000

RBX Series
300 to 10000000

Interface	Valid Setting
CNX Twin	300 to 6250000
DNX 350	300 to 8000000
RBX Series	300 to 10000000

However, the software supports speeds up to 256000 bps only. The default is 9600.

Example: set speed 19200

svc low-inbound or high-inbound or low-two-way or high-two-way or low-outbound or high-outbound value

Defines the lowest to the highest SVC channel number.

Example: set svc low-two-way 1 Inbound Specifies a range of 1 - 255. The default is 0; therefore, by default, there are no inbound only SVCs. Host-based X.25 (DNX and CNX Quad serial and RBX Series) routers have a range of 0 - 4095. Two-way Specifies a range of 1 - 255. The default is 1 for svc low and 64 for svc high. By default, there are 64 two-way SVCs. Host-based X.25 (DNX and CNX Quad serial and RBX Series) routers have a range of 0 - 4095. Outbound Specifies a range of 1 to 255. The default is 0; therefore, by default, there are no outbound only SVCs. Host-based X.25 (DNX and CNX Quad serial and RBX Series) routers have a range of 0 - 4095.

Inbound	Specifies a range of 1 - 255. The default is 0; therefore, by default, there are no inbound only SVCs. Host-based X.25 (DNX and CNX Quad serial and RBX Series) routers have a range of 0 - 4095.
Two-way	Specifies a range of 1 - 255. The default is 1 for svc low and 64 for svc high. By default, there are 64 two-way SVCs. Host-based X.25 (DNX and CNX Quad serial and RBX Series) routers have a range of 0 - 4095.
Outbound	Specifies a range of 1 to 255. The default is 0; therefore, by default, there are no outbound only SVCs. Host-based X.25 (DNX and CNX Quad serial and RBX Series) routers have a range of 0 - 4095.