When IPv6 addresses are used in policies for a particular stack, as configured to Policy Agent by using the TcpImage configuration statement, the stack must be IPv6 enabled. IPv6 policy is installed but is not enforceable in a stack that is not IPv6 enabled. If the corresponding stack is recycled later with IPv6 enabled, all policies are read and parsed again, and any policies with IPv6 addresses are enforced.

The use of IPv6 addresses in QoS policies is problematic because IPv6 interfaces can be assigned multiple IP addresses. As a result, the only way to specify IPv6 interfaces in policies is by the interface name that is specified on the INTERFACE statement. The interface name can also be used for IPv4 interfaces, as well as the IPv4 address. The name that is specified in the policies for IPv4 interfaces is the name that is specified on the LINK or INTERFACE statement in the TCP/IP profile. IPv6 interfaces can be specified for QoS policies and also for the SetSubnetPrioTosMask statement or LDAP object.

To support sysplex distributor policy performance monitoring, as specified by using the PolicyPerfMonitorForSDR configuration statement, the Policy Agent needs to establish TCP connections between the qosCollector threads that run on the distributing stacks and the qosListener threads that run on the target stacks. Depending on the sysplex configuration, either one or two connections between these threads are established. One connection is established for all target stacks that are configured for IPv4, and one connection is established for all target stacks that are configured for IPv6. Because a particular target can be configured for both IPv4 and IPv6, it is possible that two connections are established between a particular qosCollector and qosListener thread. When there are two connections, only information that is related to distributed IPv4 DVIPAs flows over the IPv4 connection, and likewise for the IPv6 connection.