Example of TCP/IP configuration statements

When you are setting up your data sharing group to use group access, looking at example TCP/IP configuration statements can be helpful.

The figures below show the TCP/IP configuration statements that are required to set up a three-member data sharing group to route DVIPA requests and perform workload balancing across the members. In these figures, the following statements apply:
  • Vx represents the group DVIPA, and V1, V2, and V3 represent the members' DVIPAs.
  • The group DVIPA and the member-specific DVIPAs are defined on each TCP/IP stack.
  • The SHAREPORT option is required only when multiple members are started on the same LPAR or TCP/IP stack; without this option, TCP/IP does not allow multiple listeners on the DRDA port.
  • The BIND (SPECIFIC) option restricts the clients to use only DVIPA to connect to Db2.
  • VIPADYNAMIC statements:
    • The group DVIPA must be defined with the VIPADEFINE and VIPADISTRIBUTE statements on the TCP/IP stacks that are associated with the systems on which the Sysplex Distributor executes.
    • The group DVIPA must be defined with the VIPABACKUP statement on the TCP/IP stacks for DVIPA takeover. Note that the VIPABACKUP statements are coded with the MOVEABLE IMMEDIATE keywords, and that the VIPADISTRIBUTE statements are also specified on the backup TCP/IP stacks. This allows for the group DVIPA to be activated on one of the backup stacks if it is not active anywhere else in the Sysplex. For example, if z/OS®-1 has not been started when z/OS-2 or z/OS-3 start up, then group DVIPA is activated on one of the backup stacks.
    • To allow for failover, the member-specific DVIPAs are defined with the VIPARANGE statement on all TCP/IP stacks.
Figure 1. Example TCP/IP network configuration (BINDSPECIFIC IPv6 dynamic virtual IP addressing)
Begin figure description. A three-member data sharing group routes DVIPA requests and performs workload balancing as described by the surrounding text. End figure description.

In this network configuration:

  1. The initial connection uses the group dynamic Virtual IP Addresses (Vx). Port 446 is identified as the DRDA port in each member's PORT statements.
  2. The Sysplex Distributor dispatches the initial connection request to the member with the lightest workload (DB2B).
  3. Resynchronization information and a list of members in the data sharing group are returned to the requester.
  4. Database-level workload balancing connections are established.
Figure 2. Example TCP/IP network configuration (INADDR_ANY IPv6 dynamic virtual IP addressing)
Begin figure description. A three-member data sharing group routes DVIPA requests and performs workload balancing as described by the surrounding text. End figure description.

In this network configuration:

  1. The initial connection uses the group dynamic Virtual IP Addresses (Vx). Port 446 is identified as the DRDA port in each member's PORT statements.
  2. The Sysplex Distributor dispatches the initial connection request to the member with the lightest workload (DB2B).
  3. Resynchronization information and a list of members in the data sharing group are returned to the requester.
  4. Database-level workload balancing connections are established.