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How many ports are utilized when a Modeler Client connects to Modeler Server?

Question & Answer


Question

How many ports are utilized when a Modeler Client connects to Modeler Server? User is receiving an error message "execution interrupted" upon executing a stream.

Answer

By default, Modeler will use any open port that is available. If it does not find a port (for example, all ports closed by a firewall), an error is displayed when the user executes the stream. Generally speaking, Modeler needs two ports (in addition to the main server port) available per concurrent stream, plus an additional three additional ports for each ODBC connection within any connected client (see 2) below for more details). It may be possible to succeed with only one port per connected stream on MS Windows. However configuring your system with two ports per stream is robust for all platforms. To execute more concurrent streams, the range of port numbers will need to be widened and opened on the firewall. It is recommended to allow a range that is sufficient to provide additional ports beyond that of a typical usage scenario to accommodate users opening additional streams etc.

1) Ensure the main Modeler Server (Default) port is open. The main port used can be found by viewing the file (modelersrvinstalldir)\config\options.cfg file.

Example: port_number, 28052

In addition to this, two ports (above and beyond main server port) are required per concurrent stream execution\connection. As documentated in the Modeler Server Administration Console Guide, you can configure Modeler Server to use a specific port range for its execution ports using the "min_server_port" and "max_server_port" parameters in the server options.cfg file. (Note: When defining the range of ports to use, do not include the current Modeler Server port in that range or it could cause a connection error. So in the example above the range should not include the 28052 port. Keep the range outside of that port.)

Example: If the maximum number of streams currently connected to a server is 20 from a client or combination of clients, then the Modeler Server options.cfg file may look like this:

min_server_port, 30000
max_server_port, 30050

Here we are configuring Modeler Server to use execution ports within the range of 51 ports, these same ports should be opened on the firewall. Please see 2) below for how the use of Database connections within streams needs to be considered in addition to this.

NOTE: Need to restart Modeler Server in order for "options.cfg" change to take effect.

2) The action of creating a database connection (ODBC) requires 3* additional ports per ODBC connection from any stream in a connected Client from within the execution port range. This is in addition to the ports used to service stream execution detailed above. *2 of these 3 ports are required for the duration of that ODBC connection, the 3rd is a temporary port required for authentication.

Example: If there is a single client machine that has 10 streams concurrently connected to the Modeler Server, and there are a total of 2 different ODBC connections within those streams, a range will be required of at least 26 ports open on the firewall and specified in max_server_port and min_server_port in the server options.cfg. NOTE: An ODBC connection is an entry in the database connections list not a database source or export node. Database source and export nodes that share the same ODBC connection share the same ODBC-related ports. Each different database connection (ie. a connection to a different ODBC DSN, or a connection to the same ODBC DSN but using a different user, requires the additional 3 ports described above).

Port usage is client-independant, ie. the same port usage would be required if a total of 10 streams with 2 database connections within them were connected from 2 different Modeler Clients.

3) Modeler will not allow a user to make a server connection from a stream that cannot obtain a port; this is at the time the stream is opened (you will see a red cross through the server connection information in the bottom left hand corner of the client for that stream).

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Historical Number

71346

Document Information

Modified date:
18 April 2019

UID

swg21488421