The IBM® sysplex distributor function provides a workload balancing function within a parallel sysplex. The sysplex distributor consists of a primary distributor stack (denoted by a dynamic VIPA) and a set of target stacks. An inbound packet destined for that DVIPA flows through the primary distributor stack which then forwards the packet over an internal link (XCF, IUTSAMEH, or HiperSockets™) to the selected target stack.
The Cisco Multi-Node Load Balancer (MNLB) provides a workload balancing function which distributes traffic through Cisco routers across multiple destination TCP/IP stacks. The MNLB consists of a service manager (the Cisco local director which is denoted by a cluster IP address) and a set of forwarding agents (Cisco routers). For a TCP connection to the cluster IP address, the forwarding agent sends the SYN packet to the service manager, which then selects a target stack and notifies the forwarding agent of this decision. The forwarding agent then sends all future packets for that TCP connection directly to the target stack.
A solution is available to enable you to use a combination of the sysplex distributor and the MNLB to provide workload balancing.
The scope of a cluster IP address managed by sysplex distributor is still a single sysplex, and integration with Cisco forwarding agents merely allows the sysplex distributor routing stack to be bypassed for inbound traffic. If workload balancing for a single cluster IP address across nodes in multiple clusters (sysplexes) is wanted, MNLB using Cisco local director as the service manager will continue to be used. Sysplex distributor will continue to advertise network ownership of the cluster IP address with any attached routing daemon so that sysplex distributor appearance and behavior toward the attached routing network is unchanged except for its new relationship with Cisco forwarding agents.
This solution allows the choice of providing the workload distribution inside the sysplex, outside the sysplex, or a combination of both.