# Link latency manager (smart data flow) The link latency manager (LLM) subsystem provides the client with APIs, which allow the client to optimize the latency levels. Application vendors can set the LLM level within a given range of L1 to L6 levels for uplink and downlink. For more information, see [level](https://docs.qualcomm.com/doc/80-PK177-134/topic/level.html). Setting a lower latency level can help in latency-sensitive network use cases. These APIs are part of Smart Data Flow. - **[LLM subsystem APIs](https://docs.qualcomm.com/doc/80-PK177-134/topic/llm_functions.html)** Describes LinkLatencyManager methods with definitions, parameter, and return details. - **[LLM subsystem callback interfaces](https://docs.qualcomm.com/doc/80-PK177-134/topic/llm_callback_interfaces.html)** The following subsections describe link latency callback interfaces with descriptions and callback parameters. - **[LLM enumerations](https://docs.qualcomm.com/doc/80-PK177-134/topic/llm_enums.html)** Describes LinkLatency enum definitions. - **[Example code](https://docs.qualcomm.com/doc/80-PK177-134/topic/example_code_QC_1.html)** Sample code for using the LLM APIs. **Parent Topic:** [Modem API](https://docs.qualcomm.com/doc/80-PK177-134/topic/modem.html) Last Published: Nov 14, 2024 [Previous Topic Example code](https://docs.qualcomm.com/bundle/publicresource/80-PK177-134/topics/lce_example_code.md) [Next Topic LLM subsystem APIs](https://docs.qualcomm.com/bundle/publicresource/80-PK177-134/topics/llm_functions.md)