Db2 for z/OS and its ecosystem

Db2 for z/OS and its ecosystem

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Are you ready to convert from VTAM to TCP/IP in Db2 for z/OS?

By Paul McWilliams posted 28 days ago

  

Are you still using VTAM for communication with Db2 for z/OS? It’s time to modernize—start planning now to avoid disruption. As mentioned in a recent blog post, VTAM (Virtual Telecommunications Access Method) communication will not be supported in future Db2 releases after Db2 13.

Why TCP/IP?

Switching to TCP/IP isn’t just mandatory—it brings real advantages:

  • Enhanced security: Supports modern encryption and authentication methods like AT-TLS and JSON Web Tokens (JWT).
  • Improved performance: Reduces CPU consumption and supports 64-bit communication buffers.
  • Cost efficiency: Improves efficiency by leveraging zIIP processors.

What’s Involved in the Migration?

The migration process primarily involves updating communications database (CDB) tables and configuring security mechanisms. You’ll replace VTAM-specific entries with TCP/IP details, such as IP addresses and ports, and implement secure authentication using RACF PassTickets or RACF Identity Tokens (IDTs). Once the changes are complete and tested, you can remove VTAM-related configurations and fully disable SNA support.

Ready to Get Started?

The Db2 documentation is updated with a step-by-step guide to help you through the VTAM to TCP/IP conversion process. For the full procedure, see Converting to TCP/IP communication from VTAM in Db2 for z/OS.


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https://community.ibm.com/community/user/blogs/paul-mcwilliams1/2026/01/16/ready-to-convert-from-vtam-to-tcpip-in-db2-zos

Comments

Suman Suhag
23 days ago

Hi Dear, 

  • Future Db2 releases after Db2 13 will no longer support VTAM/SNA connectivity.

  • Organizations using VTAM must plan migration to TCP/IP to ensure continuity and leverage modern communication capabilities.

2. Why Migrate to TCP/IP

  • Enhanced Security:

    • Support for modern encryption standards (AT-TLS)

    • Modern authentication mechanisms, including JWT tokens

  • Improved Performance:

    • Reduced CPU usage

    • Support for 64-bit communication buffers, enabling larger and more efficient data transfers

  • Cost Efficiency:

    • Optimized usage of zIIP processors, reducing mainframe CPU costs

3. Key Migration Steps

  1. Update Communications Database (CDB):

    • Configure TCP/IP entries with IP addresses and ports for Db2 subsystems.

  2. Implement Secure Authentication:

    • Utilize RACF PassTickets or Identity Tokens for secure login.

  3. Test Connectivity and Functionality:

    • Validate client applications, batch jobs, and transaction flows using TCP/IP.

  4. Remove VTAM/SNA Configurations:

    • Disable SNA support in Db2 and associated VTAM definitions after successful migration.

4. Actionable Takeaways

  • Plan Early: Begin migration planning and testing ahead of future Db2 releases to prevent disruption.

  • Operational Benefits: Migration improves security, performance, and cost efficiency, beyond mere compliance.

  • Knowledge Sharing: Document migration procedures and validate all dependent applications for TCP/IP connectivity.