TCP/IP protocol

TCP/IP (Transmission Control Protocol/Internet Protocol) is a transmission protocol and addressing mechanism that creates a reliable, ordered, stream-oriented data transmission between two network peers.

Use the TCP/IP protocol driver to interface with systems communicating by TCP/IP and using length-encoding as the method for bounding messages. The driver supports several methods for separating/delimiting messages sent across the connection.

This table shows the methods for separating/delimiting messages:
Method Description
Driver message separation TCP/IP connections operate in the stream mode. The protocol trades characters between end-points. The end-point applications, the system and the remote system, must use a common delimiter scheme.

The driver makes no attempt to separate one logical message from another.

Inbound messages The remote application can deliver messages to the TCP/IP driver at any time. When the driver receives a message, it passes it into the engine for processing.
Outbound messages When a message is delivered to the driver for writing, the driver transmits any length-encoding information followed by the message body.

TCP/IP Options pane

This table shows the parameters in the TCP/IP Options pane:

Parameter Description
Client Select this for the Hub to make a connection as a client of another TCP/IP process.
Server Select this for the Hub to provide a connection point for TCP/IP clients.
Multi-Server Select this to have multiple clients simultaneously connect to one port. Click Configure to open the Multi-Server Options dialog box. Use this dialog box to configure the multi-server attributes.
Host Click List to open the Hosts List box. Use this list box to select the host name for this connection. This option is unavailable when Server is selected.
Port Click Select to open the Select Port dialog box. Use this dialog box to select the Server port.

See Server Port configuration.

When Client is selected, Port is List.

When Server or Multi-Server is selected, Port is Select.

The TCP/IP Host and Port configuration elements provide the primary description for the connection, where:

  • Host identifies the TCP/IP entity on the network (CPU).
  • Port identifies a particular networking endpoint on the machine.
  • If the driver is configured as a Client, then it opens a connection on the selected port on the host machine.
  • If it is configured as a Server, then it awaits a connection on the port on the local machine that is listed in Host.
Local Binding Address Specify the IP address or a resolvable host name, or click List to make a selection.
TCP Connection Timeout

To connect to the server, the TCP-IP thread invokes connect().

Use this option to configure the wait time. This can also be configured using the CL_TCPIP_POLLING environment variable. The polling interval is in the 50-2000 range. The default value is 200.

This affects:

  • TCP-IP
  • PDL/TCP-IP
  • Intersite ICL
IPv4/v6 Dual When IPv4/v6 dual mode is enabled and the server is bound to "0.0.0.0" and "::", one extra listening socket is created for IPv6. Local Binding Address is blank. Two sockets are created: one for IPv4 and one for IPv6, both of which are handled separately.
SSL Select this for SSL (Secure Socket Layer) configuration. When running under security, SSL (Secure Socket Layer) connections let messages pass through or from servers with encryption capabilities.

Click Configure to open the SSL dialog box.

The Mode choices reflect which option was selected: Client or Server.

All clients connecting to a multi-server must have the same configuration, that is, all must be SSL or non-SSL.

  • Select the mode from the Mode menu.
  • SSL Protocol is used to select the openSSL version from the menu. When you select an SSL protocol, a description of the selected protocol is shown in the comment field together with the mode description.
  • SSL Cipher Suites

    Set ciphers in this field. If no cipher is set, then the default cipher suites are used. If this field is not set, then the default cipher suites are used.

    Anonymous mode:

    Server: !DEFAULT:HIGH:ADH

    Client: ALL

    Non-anonymous mode:

    HIGH:RC4+RSA:+MD5:!DHE:!3DES:!EXP:!ADH:!AES256-SHA:!AES128-SHA:!EDH:!aNULL:!eNULL:!NULL

Data Options pane

This table shows the parameters in the Data Options pane:
Parameter Description
ASCII For Length, specify an integer for the message size in bytes. For example, a length of 2 means a message size less than 99 bytes; a length of 8 means a message size less than 99999999 bytes.

For Fill, specify the fill character.

For Justification, select Left or Right.

For Length Calculations, select Inclusive to include length-encoding bytes, or Exclusive to exclude length-encoding bytes.

Binary For Length, click the arrow to select the number of bytes from the menu.

For Order, select Native or Network.

For Length Calculations, select Inclusive to include length-encoding bytes, or Exclusive to exclude length-encoding bytes.

Encapsulated Use this for configuring the HL7 MLP (Minimum Layer Protocol). After selecting this option, click Configure to open the Encapsulated Options dialog box.

See TCP/IP MLP.

Close after write Select this to close the connection after a write.
Use DRIVERCTL control Select this to have the driver examine DRIVERCTL for control keys such as CLOSE, and populate DRIVERCTL when events such as a socket close happen.
Write 0-length messages Select this to write nothing to the connection.

Auto-Reconnect Options pane

This table shows the parameters for the Auto-Reconnect Options pane:

Parameter Description
Auto-reconnect Select this to automatically reestablish a broken connection.
Reopen Time Specify the minimum number of seconds to wait after connection failure before reconnection. The default is 5.
Delay connection until needed To use this feature, select Delay connection until needed and Close after write, and clear Auto-reconnect.

See Delay connection until needed.

Start-up Procedures Pane

Click Edit to open the TPS Editor. Use this to select the procedures to run when the thread starts. This is a TPS (Tcl Procedure Stream). Use it to trade messages with the remote end.