Resolving The Problem

OS/400: Communications Configuration Manual (SC41-3401-00)
© Copyright IBM Corp. 1994

Appendix 1.1.1 TCP/IP Configuration

The only difference between TCP/IP configuration for APPC over TCP/IP and that for normal TCP/IP support is host table configuration. See the TCP/IP Configuration and Reference book for information on how to configure TCP/IP.

Appendix 1.1.1.1 TCP/IP Host Table Configuration

The TCP/IP host table maps internet addresses to TCP/IP host names. For APPC over TCP/IP support, the TCP/IP host table maps internet addresses to remote location names (also called logical unit (LU) names). To use APPC over TCP/IP support, the LU name that an application uses must be mapped to an internet address. To do this, update the TCP/IP host table using the TCP/IP configuration menus. To get to the menus, use the Configure TCP/IP (CFGTCP) command. Add an entry in the host table. Specify the internet address. Then specify the corresponding LU name as the host name. See the TCP/IP Configuration and Reference book for more information about TCP/IP host table configuration.

Note: If you prefer, you can use a remote name server rather than the TCP/IP host table. See the TCP/IP Configuration and Reference book for more information about remote name servers.

Appendix 1.1.2 Allow AnyNet Support (ALWANYNET) Network Attribute

Specify *YES for the allow AnyNet support (ALWANYNET) network attribute using the Change Network Attribute (CHGNETA) command. The system looks for LU names in the TCP/IP host table only if ALWANYNET is *YES. The CL Reference has more information about the CHGNETA command.

Note: Specifying ALWANYNET(*YES) allows all AnyNet/400* support. In other words, this network attribute affects not only APPC over TCP/IP support but also sockets over SNA support. Furthermore, sockets applications run more slowly when ALWANYNET(*YES) is specified.

Appendix 1.1.3 APPC Controller Descriptions

Use the Create Controller Description (APPC) (CRTCTLAPPC) command to configure one or more APPC controller descriptions. You can attach up to 254 devices to each APPC controller. Also, each APPC controller can support up to 254 remote locations for APPC over TCP/IP communications. Specify the following parameters for the APPC controller description:

Optionally, you can specify the following parameters for the APPC controller description:

APPC controllers with a LINKTYPE of *ANYNW are not directly attached to a line. Instead, applications running over APPC controllers with a LINKTYPE of *ANYNW are routed to TCP/IP configurations.

Appendix 1.1.4 APPC Device Descriptions

The system can automatically create APPC device descriptions. You do not have to configure these unless you want to.

Appendix 1.1.5 APPC Mode Descriptions

APPC over TCP/IP support uses mode descriptions in the same way that APPC uses them. For information about creating mode descriptions, see Chapter 9. For information about operating mode descriptions, see the APPC Programming book.

Appendix 1.1.6 APPN Remote Location List

For applications that establish sessions with remote systems, define remote locations in the APPN remote location list for the remote systems they communicate with. In other words, APPC over TCP/IP communications needs the information in the APPN remote location list to determine which controller description to use when it activates the session (that is, issue the BIND command). Use the Change Configuration List (CHGCFGL) command to define the remote locations. APPN requires that all remote location names be unique. Thus, you cannot have the same remote location name in both your SNA network and your TCP/IP network. The remote control point name in the configuration list entry of the APPN remote location list must match the remote control point name of an APPC controller with a LINKTYPE of *ANYNW. See the APPN Support book for more information about the APPN remote location list.

Appendix 1.1.7 APPC Over TCP/IP Configuration Summary

You need the following communications objects for APPC over TCP/IP support: Additionally: Appendix 1.1.8 Performance

Running APPC applications over TCP/IP networks is not as fast as running APPC applications over SNA networks.

Appendix 1.1.9 APPC over TCP/IP Configuration Example

In this example, four OS/400 systems are configured to communicate with each other using APPC over TCP/IP support. The location names of the four systems are Geneva, Oslo, Shanghai, and Sydney. Default values are used for all parameters not explicitly defined. Refer to Chapter 6, Chapter 7, or the CL Reference for the complete syntax of the commands and parameters. Names (such as location names or resource names), network identifiers, and other values shown in the example are for illustration only. The values you assign to your configuration depend on your network requirements.

Appendix 1.1.9.1.1 Creating the Token-Ring Line Descriptions

The lines used in this example are token-ring lines. This is one type of line supported by TCP/IP on the OS/400 system. The command used to create the lines is the CRTLINTRN command. The following display shows the creation of one of the line descriptions. The line description for the other OS/400 systems can use the same creation parameters except that the text and resource name parameters should be changed appropriately.


Appendix 1.1.9.1.2 Creating the Network Controller and Device

There is no need to create controller and device descriptions for the TCP/IP configuration. They are automatically created when TCP/IP first uses the token-ring line.

Appendix 1.1.9.1.3 Adding the APPC Remote Location to the TCP/IP Host Table

Just as TCP/IP requires an association between a TCP/IP host name and an internet address, it also requires an association for APPC over TCP/IP. Although APPC does not use the host name concept, it does have an equivalent pair of items (the remote location name and the remote network ID). Whatever remote locations the programs on the OS/400 system are going to communicate with must be included in the TCP/IP host table (or remote name server). The locations must also exist on the remote systems. On the Oslo system, the following commands add the internet addresses and host names of the Geneva, Shanghai, and Sydney systems to the TCP/IP host table of the Oslo system.

ADDTCPHTE INTNETADR('9.5.5.2') +
HOSTNAME(GENEVA.APPN.SNA.IBM.COM)

ADDTCPHTE INTNETADR('9.5.5.3') +
HOSTNAME(SHANGHAI.APPN.SNA.IBM.COM)

ADDTCPHTE INTNETADR('9.5.5.4') +
HOSTNAME(SYDNEY.APPN.SNA.IBM.COM)

Each host name is in three parts: the location name, the network ID, and the SNA suffix. For example, the host name of the Geneva system consists of the following parts.


On the Geneva system, the following commands add the internet addresses and host names of the Oslo, Shanghai, and Sydney systems to the TCP/IP host table of the Geneva system.

ADDTCPHTE INTNETADR('9.5.5.1') +
HOSTNAME(OSLO.APPN.SNA.IBM.COM)

ADDTCPHTE INTNETADR('9.5.5.3') +
HOSTNAME(SHANGHAI.APPN.SNA.IBM.COM)

ADDTCPHTE INTNETADR('9.5.5.4') +
HOSTNAME(SYDNEY.APPN.SNA.IBM.COM)

On the Shanghai system, the following commands add the internet addresses and host names of the Geneva, Oslo, and Sydney systems to the TCP/IP host table of the Shanghai system.

ADDTCPHTE INTNETADR('9.5.5.2') +
HOSTNAME(GENEVA.APPN.SNA.IBM.COM)

ADDTCPHTE INTNETADR('9.5.5.1') +
HOSTNAME(OSLO.APPN.SNA.IBM.COM)

ADDTCPHTE INTNETADR('9.5.5.4') +
HOSTNAME(SYDNEY.APPN.SNA.IBM.COM)

On the Sydney system, the following commands add the internet addresses and host names of the Geneva, Oslo, and Shanghai systems to the TCP/IP host table of the Sydney system.

ADDTCPHTE INTNETADR('9.5.5.2') +
HOSTNAME(GENEVA.APPN.SNA.IBM.COM)

ADDTCPHTE INTNETADR('9.5.5.1') +
HOSTNAME(OSLO.APPN.SNA.IBM.COM)

ADDTCPHTE INTNETADR('9.5.5.3') +
HOSTNAME(SHANGHAI.APPN.SNA.IBM.COM)

Appendix 1.1.9.1.4 Adding the TCP/IP Local Interface and Routing Information

Running APPC over TCP/IP does not affect this process at all. Refer to the TCP/IP Configuration and Reference book for information about TCP/IP links and interfaces.

Appendix 1.1.9.2 APPC Configuration

This part of the configuration example shows the APPC controller descriptions and APPN remote location lists.

Note: By using the *NETATR value, some network configuration changes only need to be made to the network attributes. Therefore, you should use the *NETATR value whenever possible. This example does not use the *NETATR value because the example is easier to understand without it.

Appendix 1.1.9.2.1 Creating the APPC Controllers

The systems need to create APPC controllers for APPC over TCP/IP communications. A new LINKTYPE value has been established for APPC over TCP/IP because the APPC controller is not directly attached to a line description for APPC over TCP/IP support. The new LINKTYPE is *ANYNW. A controller description with LINKTYPE(*ANYNW) can support up to 254 attached APPC devices, and, hence, 254 remote location names. The following displays show the creation of the controller descriptions:

Example APPC Controller on the Oslo System:

Example APPC Controller on the Geneva System:

Example APPC Controller on the Shanghai System:



Example APPC Controller on the Sydney System:


Appendix 1.1.9.2.2 Creating the APPC Device and Mode Descriptions

The system automatically creates APPC device descriptions as they are needed. In this example, the default mode description is used.

Appendix 1.1.9.2.3 Adding Remote Locations to the APPN Remote Location Lists

To communicate using APPC over TCP/IP support, the systems require a configuration list entry for each remote location. This entry allows the OS/400 system to automatically configure the APPC device descriptions. This entry also causes the system to use APPC over TCP/IP support (rather than APPN support) to communicate with this remote location. Example APPN Remote Location List on the Oslo System: Assuming the APPN remote location list has already been created, the following command displays the APPN remote location list and allows you to change the list:

CHGCFGL *APPNRMT

The following display shows the APPN remote location list on the Oslo system:

Example APPN Remote Location List on the Geneva System: Assuming the APPN remote location list has already been created, the following command displays the APPN remote location list and allows you to change the list:

CHGCFGL *APPNRMT

The following display shows the APPN remote location list on the Geneva system:

Example APPN Remote Location List on the Shanghai System: Assuming the APPN remote location list has already been created, the following command displays the APPN remote location list and allows you to change the list:

CHGCFGL *APPNRMT

The following display shows the APPN remote location list on the Shanghai system:


Example APPN Remote Location List on the Sydney System: Assuming the APPN remote location list has already been created, the following command displays the APPN remote location list and allows you to change the list:

CHGCFGL *APPNRMT

The following display shows the APPN remote location list on the Sydney system:


Appendix 1.1.9.3 Allow AnyNet/400 Support

To communicate using APPC over TCP/IP support, the systems must allow AnyNet/400 support. To allow AnyNet/400 support, the allow ANYNET support (ALWANYNET) network attribute must be *YES. The following command, issued on all four systems, ensures that the systems allow the use of AnyNet/400 support, which includes APPC over TCP/IP support.

CHGNETA ALWANYNET(*YES)

Appendix 1.1.9.4 Matching Parameters

The following diagram shows the parameters that need to match for the Oslo and Geneva systems in this APPC over TCP/IP configuration example.

Oslo OS/400 System                                 Geneva OS/400 System
  Network Attributes                                 Network Attributes
      ALWANYNET   *YES                                   ALWANYNET   *YES
     LCLLOCNAME  OSLO                                   LCLLOCNAME  GENEVA
     LCLNETID    APPN <--------------------+  +-------> LCLNETID    APPN
                                           |  |
     TCP/IP Host Table                     |  |         TCP/IP Host Table
       INTNETADR  9.5.5.2                  |  |           INTNETADR  9.5.5.1
       HOSTNAME   GENEVA.APPN.SNA.IBM.COM  +--+------+    HOSTNAME   OSLO.APPN.SNA.IBM.COM
                    A     A                   |      |                 A   A
+-------------------+     +-------------------+      +-----------------+---+
|                                             |      |                 +----------------+
|    APPC Controller Description              |      |  APPC Controller Description     |
|      CTLD       OSLOANYCD                   |      |    CTLD       GENEVANYCD         |
|      LINKTYPE   *ANYNW                      |      |    LINKTYPE   *ANYNW             |
|+---> RMTNETID   APPN <----------------------+      +--> RMTNETID   APPN <-------------+----+
||+--> RMTCPNAME  TCPIP1                      |      |    RMTCPNAME  TCPIP2 <-----------+--+ |
|||                                           |      |                                  |  | |
|||  APPN Remote Location List                |      |                                  |  | |
+++--> Remote location       GENEVA <---------+--+   |                                  |  | |
 ||    Remote network ID     APPN <-----------+  |   |  APPN Remote Location List       |  | |
 ||    Local location        OSLO <--------------+---+--> Remote location       OSLO <--+  | |
 |+--> Remote control point  TCPIP1              |   +--> Remote network ID     APPN       | |
 +---> Control point net ID  APPN                +------> Local location        GENEVA     | |
                                                          Remote control point  TCPIP2 <---+ |
                                                          Control point net ID  APPN <-------+

Figure A-1. APPC over TCP/IP Configuration Matching Parameters