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6 Appendix A: Product Behavior

  • Article

The information in this specification is applicable to the following Microsoft products or supplemental software. References to product versions include updates to those products.

  • Windows NT operating system

  • Windows 2000 operating system

  • Windows XP operating system

  • Windows Server 2003 operating system

  • Windows Vista operating system

  • Windows Server 2008 operating system

  • Windows 7 operating system

  • Windows Server 2008 R2 operating system

  • Windows 8 operating system

  • Windows Server 2012 operating system

  • Windows 8.1 operating system

  • Windows Server 2012 R2 operating system

  • Windows 10 operating system

  • Windows Server 2016 operating system

  • Windows Server 2019 operating system

  • Windows Server 2022 operating system

  • Windows 11 operating system

  • Windows Server 2025 operating system

Exceptions, if any, are noted in this section. If an update version, service pack or Knowledge Base (KB) number appears with a product name, the behavior changed in that update. The new behavior also applies to subsequent updates unless otherwise specified. If a product edition appears with the product version, behavior is different in that product edition.

Unless otherwise specified, any statement of optional behavior in this specification that is prescribed using the terms "SHOULD" or "SHOULD NOT" implies product behavior in accordance with the SHOULD or SHOULD NOT prescription. Unless otherwise specified, the term "MAY" implies that the product does not follow the prescription.

<1> Section 1.5: The DirectPlay 4 Protocol is available only in Windows operating systems that have the DirectX 6 runtime (from the DirectX 6 Software Development Kit (DirectX SDK)) or a later version of the runtime installed. All Microsoft products listed above meet this requirement.

<2> Section 2: NACK frames are not implemented in Windows DirectPlay 4 implementation.

<3> Section 2.2.2: The Windows DirectPlay 4 implementation does not support extended flags and therefore does not set or expect to receive messages with the EXT bit set.

<4> Section 2.2.2: Because the extended flags field is not supported by Windows implementations, the NACK MASK field is also not supported

<5> Section 2.2.3: The Windows DirectPlay 4 implementation does not support extended flags and therefore does not set or expect to receive messages with the EXT bit set.

<6> Section 2.2.3: Because the extended flags field is not supported by Windows implementations, the NACK MASK field is also not supported.

<7> Section 3.1.5.2: The Windows DirectPlay 4 implementation sends NACKs without waiting for more time to elapse or more data to be received.

<8> Section 3.1.5.2: The Windows DirectPlay 4 implementation sets the SAK bit when any one of the following applies:

  • The EOM bit is not set or the higher layer requested the message to be sent using reliable delivery, and the time since the last SAK request is greater than 50 milliseconds and greater than one quarter of the estimated round-trip latency of the connection.

  • The packet is being retransmitted.

  • There have been 24 packets since the last packet was sent with the SAK bit set.