Customize VTAM for Db2
For Db2 to provide the best performance for distributed database systems, you probably need to customize VTAM®.
Before you begin
Tip: TCP/IP is the recommended communication protocol for communication with Db2 for z/OS®. Although SNA communication remains supported in Db2 13, SNA communication and the VTAM interface are deprecated, and support will be removed in the future. 
If your Db2 environment still uses VTAM communication, see Converting to TCP/IP communication from VTAM in Db2 for z/OS.
If your Db2 environment still uses VTAM communication, see Converting to TCP/IP communication from VTAM in Db2 for z/OS.Before you customize VTAM, consider the communication needs of your Db2 connections. Because you could allow your Db2 subsystem to send large amounts of data through the network, reexamine the capacity of your existing network. In some cases, portions of your existing network might need additional communication hardware to provide the required capacity.