HP OpenVMS Systems Documentation

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DECnet-Plus for OpenVMS
Network Management

Previous Contents Index Disabling DECnet Over TCP/IP

On OpenVMS systems, DECnet-Plus will only try to locate TCP/IP if the rfc1006 listener ports attribute set of the osi transportentity is not empty.

To disable DECnet over TCP/IP, issue the following command:

ncl> set osi transport rfc1006 listener ports {} DECnet over TCP/IP Tracing Support with Common Trace Facility (CTF)

CTF can be used to trace all PDUs transmitted and received by DECnet over TCP/IP and OSI applications. See Appendix A in the DECnet/OSI for VMS CTF Use for a list of events that are recognized at this trace point.

Use the following command to invoke the CTF tracing utility:

$ TRACE START "trace-point"

where trace-point is the trace point to be started, such as "TPCONS TPKT *". Recovering from Problems

If you have problems getting DECnet over TCP/IP to start up properly, check the following:

  1. Verify that you have an OSI transport template with network service attribute defined as rfc1006.
    Issue the command:

    ncl> show osi transport template * with network service = rfc1006

    If you do not have a template defined, then you must execute NET$CONFIGURE Option 4 and replace your OSI transport startup script.
  2. Verify that you have your TCP/IP product started and that your product supports the PWIP interface. If you are running DIGITAL TCP/IP services for OpenVMS, PWIP can be configured to start automatically. If PWIP does not start automatically, run UCX$CONFIG and enable the PWIP interface.
  3. Verify that the PWIP interface is properly registered. Using the management tool of the installed TCP/IP product, verify that rfc1006 listener port defined in OSI transport is known by TCP/IP. If you are running DIGITAL TCP/IP Services for OpenVMS, use the following command:

    $ ucx show device
                                Port                       Remote
    Device_socket  Type    Local  Remote  Service           Host
      bg3         STREAM      23       0  TALENT 
      bg4         DGRAM      520       0         
      bg7         STREAM     399       0         
      bg9         STREAM     102       0         

    In this case, look for the two listener ports 399 and 102.

If IP addresses work but IP names do not, use your TCP/IP management tool to verify that your BIND server knows about the name. Connection Auditing

You can audit incoming connections for those connections that are made using DECnet over TCP/IP. The audit alarm is displayed as follows:

%%%%%%%%%%%  OPCOM   9-FEB-1995 12:26:11.64  %%%%%%%%%%%
Message from user AUDIT$SERVER on PETERB
Security alarm (SECURITY) and security audit (SECURITY) on PETERB, system id:
Auditable event:          DECnet logical link created
Event time:                9-FEB-1995 12:26:11.59
PID:                      000000A6
Process name:             FAL_14010028
Username:                 SYSTEM
Process owner:            [1,3]
Image name:               SYS$COMMON:[SYSEXE]FAL.EXE
Remote node id:           1560286224
Remote node fullname:     MYNODE.LKG.ACME.COM
Remote username:          CAISSON
DECnet logical link ID:   335609896
DECnet object name:       FAL Proxy Access

DECnet over TCP/IP allows you to use fully qualified domain names in your OpenVMS proxy database. For example:

UAF> add/proxy mynode.lkg.acme.com::caisson caisson/default

A node can have more than one full name for a node. This means that proxy records for each of the possible node names need to be added using the Authorize utility. For example, if your system is set up to use both DECdns and BIND (and you can see a remote node's name as either of these), then you need to add proxy records for both nodes. To represent the remote node stir, you would need to add these proxy records: STIR.ENET.ACME.COMand DEC:.ZKO.STIR.

8.6 Managing Session Control

You can manage session control by adding network applications, deleting network connections, and deleting network entities.

8.6.1 Adding a Session Control Network Application

The following example shows how to add a session control network application (which was known as a session control object in Phase IV):

ncl> create session control application application-name

ncl> set session control application application-name -
_ncl> image name image-name -

_ncl> user name user-name -
_ncl> data abstraction {message} -

_ncl> accept mode {deferred } -
_ncl> programming interface {Phase IV} -

_ncl> address {number = nn,....} (1)
  1. You can identify an application with an object number. Usually, applications are identified by network object number 0, but you can optionally assign it a nonzero object number, in the range from 128 to 255. A nonzero object number can be specified without an application name. Object numbers 1 through 127 are reserved for use by Digital Equipment Corporation. Specific network services are identified by nonzero object numbers; for example, 27 represents the mailutility:

    ncl> set session control application mail addresses {number=27}

Table 8-8 maps NCP characteristics to NCL attributes.

Table 8-8 NCP to NCL Command Conversions
NCP Characteristic NCL Attribute
user user name
file image name
number address

8.6.2 Deleting a Connection

You can selectively delete connections on a local system while the network is running. For example:

ncl> delete session control port port-name

8.6.3 Deleting and Recreating the OSI and NSP Entities

If after deleting any child entities of session control, such as the osi portand nspentities, you create them again, you must use NCL to notify session control that the previously disabled entities are available again. Sections and show the commands to use to delete and recreate the osi and nspentities. Requirements for Deleting and Creating the OSI Transport Entity

If the osi transportentity is deleted and subsequently recreated, you must issue the following directives to inform DNA session control that the OSI transport service is available:

ncl> delete session control transport service osi
ncl> create session control transport service osi protocol %x05

You cannot issue the delete session control transport service osi command while osi portentities exist. Requirements for Deleting and Creating the NSP Entity

If the nsp entity is deleted and subsequently recreated, you must issue the following directives to inform DNA session control that the NSP transport service is available:

ncl> delete session control transport service nsp
ncl> create session control transport service nsp protocol %x04

You cannot issue the delete session control transport service nsp command while nsp portentities exist.

8.7 Managing OSAK

Open System Application Kernel (OSAK) is DIGITAL's implementation of the OSI upper layers. It provides OSI session, presentation and application services. These services are used by OSI applications such as FTAM and VT. You must use NCL to manage the OSAK software on your system. For further details of the NCL commands to use, refer to the DECnet-Plus Network Control Language Reference guide.

Figure 8-8 shows the osak entity and its subentities.

Figure 8-8 osak Entity

8.7.1 Managing OSAK Addresses

You can implement your OSI application using either of two types of application address: active or passive.

An active address is associated with a process that is already started on the system. A passive address is associated with a process that is started only when a connection request is received for that address.


Passive application functionality requires the OSAK server component, which is available only on OpenVMS systems. Registering Active and Passive Addresses

You cannot actively manage active addresses; NCL creates the necessary management entities when OSAK sends or receives an appropriate programming call. You use NCL to register passive addresses. This section describes how to register active and passive addresses.


An application registers an active address by passing that address on a call to osak_open_responder or osak_open_initiator. NCL creates the appropriate entities. You can use the NCL show command to show attributes of these entities.


You register an application address using Network Control Language (NCL) commands to create an osak application entity and an osak application invocation entity. Use the startup information attribute of the osak application invocation entity to specify the values in Table 8-9.

Table 8-9 Startup Information Values
Item Value Description
user name The user name of the process that will respond to Connect requests received by this application
file pathname The name of the file to run to start up the named application
account name The account that is to start the process
max resp integer The highest permissible number of responders, for an application with the NEW setting for startup policy
password password The user's password
sversion {1}, {2}, or {1,2} The session version

Further Information

For more information about the OSAK module, refer to the DECnet-Plus Network Control Language Reference guide.

8.7.2 NCL and the OSAK Databases

OSAK maintains two databases: the application database and the port database. You must use NCL to inspect information held in the OSAK databases and to set attributes of entities in the OSAK module. Table 8-10 shows the mapping between NCL and OSAK management.

Table 8-10 Mapping Between NCL and OSAK
OSAK Database NCL Entity
Application database osak application
osak application invocation
Port database osak port

8.7.3 Supporting the OSAK Component of DECnet-Plus

This section describes how you can check that the OSAK component of DECnet-Plus is working correctly and support OSI applications that are running over this component.


To check whether an OSI application runs over the OSAK component of DECnet-Plus, refer to the documentation for that application.

The best indication that the OSAK component is working normally is when any OSI application you are running behaves predictably and efficiently. However, there are tasks you can complete at convenient intervals to monitor the working of the software:

  • Check the numbers of connections, aborts, and releases that occur by examining the OSAK counters (see Section
  • Check the occurrence of upper layer events by using the DECnet-Plus event dispatching facility (see Chapter 12)
  • Check which ports and addresses are active (see Section Counting Connections, Releases, and Aborts

To check the number of connections, releases, and aborts that occur while your application is running, look at the values of the OSAK counters. You can discover what is normal for your application over a period of time; abnormal values may then be an indication that something is going wrong.

You can display the values of all the OSAK counters by using the following NCL command:

ncl> show [node node_id] osak all counters

You can display the value of a specified OSAK counter by using the following command:

ncl> show [node node_id] osak counter_name


node_id The identifier of the node on which the osak entity resides
counter_name The name of the counter whose value you want to check Monitoring Upper Layer Events

You can monitor the occurrence of events, and find out the rate of occurrence that is normal and acceptable for the application you are running. A more frequent occurrence might be an indication that the application you are running is not working properly.

See Chapter 12 for information about the DECnet-Plus event dispatching facility. Checking Ports and Addresses

You can display the following information, which may help you to check that your application is running as you expect it to:

  1. A list of open ports, which includes the following information:
    • Whether a port is being used for an inbound or an outbound connection. The direction status attribute gives you this information.
    • Presentation address (if any) to which the port is connected. The local paddress status attribute gives you this information.
    • The state of the port. The connection state status attribute gives you this information.
      Use the following NCL commands to get this information:
      • Display a list of open ports:

        ncl> show [node node_id] osak port *
      • Select the port in which you are interested and display all the attributes:

        ncl> show [node node_id] osak port port_id all

        Here, port_id is the identifier of the port in which you are interested.
  2. A list of the upper-layer addresses that are waiting for inbound associations.
    Use the following NCL command to get this information:

    ncl> show [node node_id] osak port *, -
    _ncl> with connection state = awaiting_inbound_connection

8.8 Configuring X.25 Services

DECnet-Plus and the software products that implement X.25 are packaged separately. They can be used independently on the same system.

DECnet-Plus for OpenVMS supports the following approaches for configuring and using the features of X.25 products:

  • Configuring the osi transport entity to use the connection-oriented network service (CONS) interface to X.25, enabling the use of OSI transport classes 0 and 2 (TP0 and TP2). OSI Transport establishes an X.25 channel only for the duration of the application's connection to the remote system.
  • Configuring the routing entity, which provides Connectionless-Mode Network Service (CLNS), to use an X.25 switched virtual circuit (SVC) as a dynamically-assigned data link to a remote network. DECnet-Plus waits until an application requests a connection to the remote network before establishing the link. DECnet-Plus disconnects the link when no applications have an open connection to the remote network. The remote network is considered outside the local routing domain. You must manually configure which CLNS addresses are reachable over the X.25 link. X.25 dynamically-assigned datalinks cannot be used to access a DECnet phase IV node.
  • Configuring the routing entity, which provides Connectionless-Mode Network Service (CLNS), to use an X.25 permanent virtual circuit (PVC) as a data link to a remote network. PVCs are permanent channels established by the X.25 service provider. DECnet-Plus establishes a link through the X.25 PVC at startup. It then autoconfigures itself into the remote DECnet Phase V or DECnet Phase IV network.
  • Configuring the routing entity to use an X.25 switched virtual circuit (SVC) as a static data link to a remote network. This approach does not require the X.25 service provider to create a permanent channel. To establish a link, DECnet-Plus calls or receives an X.25 call from a remote system during startup. It keeps the link open until disabled by network management commands. As with PVCs, DECnet-Plus will autoconfigure itself into the remote DECnet Phase V or DECnet Phase IV network.

These approaches are completely optional, but might be desirable for use with certain applications or for particular network configurations. They can function individually or together on the same system.

The Connection-Oriented Network Service (CONS) is an ISO specification for a reliable and transparent end-to-end data transfer function. OSI transport can use CONS in addition to the Connectionless-Mode Network Service (CLNS) implemented by DNA routing.

Note that applications using OSI transport (for example, FTAM or Virtual Terminal) need to be configured to operate over CONS before they can use CONS functionality.

Applications using routing over X.25 circuits do not require any special configuration. X.25 serves as another communications path from the local end system to the remote sytem.

8.8.1 Configuring DECnet-Plus to Use X.25

Once X.25 has been installed, you can use the DECnet-Plus configuration procedure (NET$CONFIGURE.COM) to first configure X.25 and then configure DECnet over X.25. You can use either the basic or advanced configuration option.

See DECnet-Plus for OpenVMS Applications Installation and Advanced Configuration for more information about configuring X.25 support on DECnet-Plus for OpenVMS systems.

Full details on how to configure the X.25 product are provided in the X.25 for OpenVMS documentation. This guide is available in a separate kit. Refer to the Software Product Description (SPD) for appropriate part numbers to use for ordering the X.25 kit.

The details of each type of configuration are described in Section (OSI Transport using CONS) and Section (for routing using X.25).

DIGITAL strongly recommends that you configure and test both DECnet-Plus and X.25 independently before attempting to configure DECnet-Plus to use X.25.

Figure 8-9 shows the x25 protocol entity and its subentities.

Figure 8-9 x25 protocol Entity

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