Knowledge

WSA_QOS_EPSFILTERSPEC - 11028 (0x2B14)

An invalid FILTERSPEC was found in the QOS provider-specific buffer.

Updated: Feb 21, 2026

Technical Background

The WSA_QOS_EPSFILTERSPEC error code is encountered when the Windows Sockets API detects an invalid FILTERSPEC in a Quality of Service (QoS) provider-specific buffer. This error typically occurs during the configuration or setup of QoS policies for network communications.

Error Details

Numeric Code: 11028 (0x2B14)

This specific error code is associated with issues related to the FILTERSPEC parameter in QoS configurations.

Hexadecimal Code: 0x2B14

The hexadecimal representation of the error code provides a unique identifier for this particular issue within the Windows Sockets API framework.

Common Causes

  • Invalid Parameter Values: The FILTERSPEC provided is not valid or does not conform to the expected format required by the QoS provider.
  • Incorrect Object Type: The object type specified in the FILTERSPEC may be incorrect, leading to an invalid configuration.
  • Exceeding Limits: There might be a limit on the number of filters that can be configured, and attempting to exceed this limit could result in this error.

Real-World Context

This error is commonly encountered when developing applications that require fine-grained control over network traffic using QoS mechanisms. Developers must ensure that all parameters passed to the Windows Sockets API are correctly formatted and adhere to the specified constraints.

Is This Error Critical?

The criticality of this error depends on the application's requirements. For most applications, encountering this error indicates a configuration issue that needs to be addressed before successful operation can be achieved.

How to Diagnose

  1. Review Operation Context: Ensure that the context in which the QoS policy is being configured aligns with the expected usage.
  2. Validate Parameters: Verify that all parameters, including FILTERSPEC, are correctly formatted and within acceptable ranges.
  3. Confirm Object Types: Double-check that the object types specified in the FILTERSPEC match the expected values for the specific QoS provider.

How to Resolve

  1. Correct Parameter Usage: Ensure that the FILTERSPEC is properly formatted according to the documentation provided by the QoS provider.
  2. Adjust Operation Context: If the operation context is incorrect, adjust it to ensure compatibility with the QoS configuration requirements.
  3. Restore Data: In cases where data corruption might be a factor, restore or reconfigure the FILTERSPEC to its correct state.

Developer Notes

Developers should consult the official Windows Sockets API documentation for detailed information on the expected format and constraints of the FILTERSPEC. Additionally, testing with various scenarios can help identify potential issues early in the development process.

Related Errors

  • WSA_QOS_INVALID_PARAMETER: This error might be encountered if other parameters are invalid.
  • WSA_QOS_POLICY_NOT_SUPPORTED: Indicates that the QoS policy being attempted is not supported by the current configuration or environment.

FAQ

What does WSA_QOS_EPSFILTERSPEC mean?

This error indicates an issue with the FILTERSPEC parameter in a Quality of Service (QoS) provider-specific buffer, typically due to invalid values or incorrect object types.

How can I prevent this error from occurring?

Ensure that all parameters passed to the Windows Sockets API are correctly formatted and within acceptable ranges. Consult the documentation for specific constraints on FILTERSPEC.

Can this error be critical for my application?

The criticality depends on your application's requirements. If QoS is essential, addressing this error promptly is crucial to ensure proper network traffic management.

Summary

The WSA_QOS_EPSFILTERSPEC error code signifies an issue with the FILTERSPEC parameter in a Quality of Service (QoS) provider-specific buffer. Developers should validate parameters and ensure correct usage context to resolve this error effectively.