# OpenTracing
Site [llms.txt](/llms.txt)
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## OpenTracing Attributes
**Attributes:**
| Key | Stability | Value Type | Description | Example Values |
| --- | --- | --- | --- | --- |
| `opentracing.ref_type` | 
OpenTracing compatibility requirements are [deprecated in OpenTelemetry Specification](/docs/specs/otel/compatibility/opentracing/) | string | Parent-child Reference type [1] | `child_of`; `follows_from` [(see more)](#opentracing-ref-type-values) |
**[1] `opentracing.ref_type`:** The causal relationship between a child Span and a parent Span.
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`opentracing.ref_type` has the following list of well-known values. If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used.
| Value | Description | Stability |
| --- | --- | --- |
| `child_of` | The parent Span depends on the child Span in some capacity |  |
| `follows_from` | The parent Span doesn't depend in any way on the result of the child Span |  |