FTP use cases

The FTP workspaces were created to facilitate investigation of issues with FTP sessions and transfers within the network.

These use cases address the navigation paths shown in Figure 1:
Figure 1. FTP navigation paths
FTP navigation paths

Identifying FTP sessions with large numbers of transfers

A system programmer is investigating a performance issue with an application transferring files using FTP. He needs to quickly identify any FTP sessions that have transferred a large number of files, even small files.

  1. He navigates to the Enterprise FTP Sessions Overview workspace and looks at the FTP Sessions Summary subpanel.
  2. He filters by Total Files Transferred greater than 100 and removes the State = ‘Active’ filter to view the active and closed FTP sessions that have transferred 100 or more files.
  3. He identifies an FTP session that has been transferring 100 files per minute, a billion bytes per hour.
  4. When this application was moved, this move had a major impact because the application was sending many files.
  5. After identifying the high-overhead application, he contacted the application owner.

Determining why FTP is running slowly

A user calls the help desk and complains that FTP is running slowly.

  1. The mainframe network system programmer navigates to the Enterprise FTP Sessions Overview workspace and views the FTP Sessions Summary subpanel..
  2. She filters on TCP STC Name.
  3. She finds the active FTP session that the user complained about.
  4. She navigates to the FTP Transfers for Session with Application_Name workspace to view information about the FTP transfers.
  5. She notices that a number of transfers have completed, all of which were successful.
  6. Reviewing the Transfer Duration and Total Bytes Transmitted column, she notes that the transfers are taking a long time relative to the file size.
  7. She enters C to navigate to the Connection Details workspace to view the underlying TCP connection for the FTP session.
  8. She reviews the metrics and finds no performance issues on the control connection.
  9. She returns to the FTP Transfers for Session with Application_Name workspace.
  10. She selects the active FTP transfer and navigates to the FTP Transfer Details workspace.
  11. She reviews the Transfer TCP Connection subpanel and discovers both retransmissions and out-of-order segments.
  12. She navigates to the Connection Details workspace to view all the TCP Connection attributes.
  13. She runs a packet trace to determine the reason for the retransmissions and out-of-order segments

Troubleshooting an invalid FTP user ID or password

An enterprise is experiencing a high volume of FTP traffic. A frequent problem is internal FTP failures because of invalid passwords or user IDs. Periodically, the systems programmer looks for failed FTP login attempt.

  1. The mainframe network systems programmer navigates to the Enterprise FTP Sessions Overview workspace and views the FTP Login Failures Summary subpanel.
  2. He sorts the subpanel by user ID to find users that have repeatedly failed to login.
  3. He filters the rows by setting an SMF ID in the upper right of the panel and pressing Enter , thus narrowing his search to the rows for a single system (or set of systems, if he used a wildcard).
  4. He identifies a user who attempted to login with an invalid password until the password was revoked. He observes that three rows of the table record with a Login Failure Reason value of invalid password, followed by three rows with a Login Failure Reason value of password revoked.
  5. He contacts the user and resets the password.

Determining why an FTP connection cannot be completed

A user attempted to transfer files to a z/OS® LPAR, but the connection could not be completed, and the mainframe timed out trying to upload data.

  1. The mainframe network systems programmer needed to first investigate the size of the transfer and determine whether it was a large transfer or a small one. She navigates to the Enterprise FTP Sessions Overview workspace.
  2. She enters in the SMF ID for the reported LPAR and presses Enter to view only the active or completed FTP sessions for the reported LPAR.
  3. She sorts the FTP Sessions Failures Summary subpanel by Job Name and finds the reported Job Name (user ID).
  4. She notes that there was a socket or network error.
  5. She navigates to the FTP Session Details workspace to review the remaining FTP Session attributes, but does not find any indication of the problem.
  6. She investigates further, searching for anything unusual in the network and finds no problems with the TCP/IP stack.
  7. She contacts the distributed network team for further assistance.