QDIO Accelerator

The QDIO Accelerator function extends the HiperSockets Accelerator function. HiperSockets Accelerator provides accelerated forwarding at the DLC layer for the following types of packets:

  • Inbound packets over HiperSockets that are forwarded outbound over OSA-Express® QDIO
  • Inbound packets over OSA-Express QDIO that are forwarded outbound over HiperSockets

For more information about HiperSockets Accelerator, see Efficient routing using HiperSockets Accelerator.

QDIO Accelerator provides all of the function supported by HiperSockets Accelerator, and also provides accelerated forwarding at the DLC layer for the following types of packets:

  • Inbound packets over OSA-Express QDIO that are forwarded outbound over OSA-Express QDIO
  • Inbound packets over HiperSockets that are forwarded outbound over HiperSockets
  • Sysplex distributor packets that are forwarded to a target stack or that are forwarded to or from a DataPower® appliance, when the route involves any of the following inbound and outbound DLC combinations:
    • Inbound over HiperSockets, forwarded outbound over OSA-Express QDIO
    • Inbound over OSA-Express QDIO, forwarded outbound over HiperSockets
    • Inbound over OSA-Express QDIO, forwarded outbound over OSA-Express QDIO
    • Inbound over HiperSockets, forwarded outbound over HiperSockets
    For more information about sysplex distribution with a DataPower appliance, see Sysplex distribution with DataPower.

QDIO Acceleration is supported with or without the VIPAROUTE statement. When QDIO Accelerator is active, the stack dynamically creates QDIO Accelerator routes as it forwards packets in any of the inbound and outbound DLC combinations previously described. The DLC layer can perform accelerated routing for packets across these routes, bypassing the IP forwarding function in the stack. Similarly, the stack dynamically creates QDIO Accelerator routes for packets that would be forwarded by the sysplex distributor in any of the inbound and outbound DLC combinations. The DLC layer can perform accelerated sysplex distributor routing for such packets.

To configure QDIO Accelerator, specify the QDIOACCELERATOR parameter on the IPCONFIG statement. For more information about the IPCONFIG statement, see z/OS Communications Server: IP Configuration Reference.

You can display the QDIO Accelerator routing entries that are dynamically created for non-sysplex distributor packets using the Netstat ROUTE/-r report option with the QDIOACCEL modifier. For more information about the Netstat ROUTE/-r report, see z/OS Communications Server: IP System Administrator's Commands.

You can use the Netstat VCRT/-V report with the DETAIL modifier to display whether a sysplex distributor connection is eligible for acceleration. For more information about the Netstat VCRT/-V report, see z/OS Communications Server: IP System Administrator's Commands.

You can also use VTAM® tuning statistics to monitor and measure the accelerated packets. For more information about gathering tuning statistics, see z/OS Communications Server: SNA Network Implementation Guide.

Restrictions:
  • QDIO Accelerator is supported for IPv4 only.
  • If IP security is enabled on the stack, the stack monitors IP filter rules and defensive filter rules that apply to routed traffic. Depending on your filter configuration, QDIO Accelerator might be restricted to only packets that are forwarded by the sysplex distributor. For more information about QDIO Accelerator and IP security, see QDIO Accelerator and IP security.
  • If IP forwarding is disabled on the stack, then QDIO Accelerator applies only to packets that are forwarded by the sysplex distributor.
  • Packets from the sysplex distributor to the target are not accelerated with the VIPAROUTE destination when the outbound interface is HiperSockets.
Tip: If packet trace is enabled, then packets that are accelerated by QDIO Accelerator do not appear in the packet trace (either inbound or outbound). If you want function similar to that of the packet trace in conjunction with QDIO Accelerator, you can use the OSA-Express network traffic analyzer (OSAENTA) to trace these packets that are accelerated to or from OSA-Express QDIO. For more details on OSAENTA, see OSA-Express network traffic analyzer trace.