Communicating with data sharing groups

A data sharing group can be a powerful server in your client/server environment. The group can be part of a TCP/IP network, part of an SNA network, or part of a network that uses both protocols.

The group has a single-system image to requesting applications, whether requests arrive through TCP/IP or SNA. Queries can originate from any system or application that issues Structured Query Language (SQL) statements as a requester in the formats that are described by Distributed Relational Database Architecture (DRDA).

The distributed data facility (DDF) of Db2 uses TCP/IP and SNA to communicate with other Db2 subsystems.

Tip: TCP/IP is the recommended communication protocol for communication with Db2 for z/OS®. Although SNA communication remains supported in Db2 12, 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.

The DDF enables a Db2 subsystem to access data that is held by other database management systems. The DDF also enables the Db2 subsystem to make its own data accessible to other Db2 subsystems.

A data sharing group can support many more connections than a single member of the group can support. The DDF connections limit for a group is n × 150,000, where n is the number of members in the group. Thus, a group with 16 members can support 2,400,000 DDF connections.