I’ve been doing a bit of investigation recently into the number of connections IBM MQ Managed File Transfer V9.1 LTS agents make to their agent queue manager. Here, for reference, are my findings.

Connections created by idle agents

When an agent starts up, it creates 4 connections to the agent queue manager. These connections will be around for the lifetime of the agent, and are used by the agent to:

  • Monitor the various system queues on the agent queue manager.
  • Publish status information to the SYSTEM.FTE topic on coordination queue manager, via the agent queue manager, at regular intervals.

Connections created during managed transfers

Managed transfers contain three distinct phases:

  • Phase 1: Transfer negotiation
  • Phase 2: Transferring data.
  • Phase 3: Transfer completion.

The number of connections that an agent will create to its agent queue manager during each phase depends upon the type of managed transfer being performed, and the agent’s role in the managed transfer.

Table 1: Connections created for file-to-file transfers

Phase 1

Phase 2

Phase 3
Source Agent

2

1

1
Destination Agent

1

1

0


Table 2: Connections created for message-to-file transfers

Phase 1

Phase 2

Phase 3
Source Agent

2

1

2
Destination Agent

1

1

0


Table 3: Connections created for file-to-message transfers

Phase 1

Phase 2

Phase 3
Source Agent

2

1

1
Destination Agent

1

1

0


There are a couple of things to note here:

  • The connections are created at the start of each phase, and are closed off before the phase completes.
  • During Phase 2, an agent will only create a single connection to its agent queue manager, regardless of the number of transfer items in the managed transfer.

Connections created by resource monitors

Every resource monitor will create 1 connection to the agent queue manager when it performs a poll. The connection is closed when the poll has finished.

As always, I hope this helps! If you have any questions on this, feel free to ask and I’ll be happy to get back to you.

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