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. Although SNA communication remains supported in Db2 12, SNA communication (including the VTAM interface) is deprecated, and support might be removed in the future. You can disable SNA communication by setting the value of the DB2 TCP/IP IPNAME setting. See DB2 TCP/IP IPNAME field.

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.