UL TFT (uplink traffic flow template)

Last updated on Jul 21, 2023

Uplink Traffic Flow Template (UL TFT):

The Uplink Traffic Flow Template (UL TFT) is a concept used in mobile communication networks, particularly in the context of 3GPP (3rd Generation Partnership Project) specifications for cellular systems like LTE (Long-Term Evolution) and 5G NR (New Radio). The UL TFT is an essential element in Quality of Service (QoS) management for uplink data transmission, providing a set of rules that govern how different uplink traffic flows are treated within the network.

Background:

In mobile communication networks, various applications and services generate different types of data traffic with diverse QoS requirements. Some applications, such as real-time voice and video services, require low latency and high priority, while other data services, like email and web browsing, can tolerate higher latency and have lower priority. The UL TFT is used to differentiate and manage these traffic flows, ensuring that each receives the appropriate level of QoS according to its requirements.

UL TFT Parameters:

A UL TFT consists of several parameters that define the characteristics and treatment of a specific uplink traffic flow. These parameters include:

Traffic Filter: The traffic filter is a set of rules that define the type of data packets or packets from a specific application or source that belong to the particular traffic flow. It is based on packet headers, such as source IP address, destination IP address, port numbers, and protocol type.
QoS Parameters: QoS parameters in the UL TFT specify the desired level of service for the traffic flow. These may include priority levels, packet delay budget, packet loss rate, and data rate requirements.
Flow Identifier: Each UL TFT is assigned a unique flow identifier that distinguishes it from other traffic flows within the network.

Role of UL TFT in QoS Management:

When a mobile device (UE - User Equipment) initiates an uplink data transmission, the network examines the data packets' headers to match them against the defined traffic filters in the UL TFTs. Based on the matched traffic flow, the network applies the corresponding QoS parameters to treat the data packets appropriately.

The UL TFT helps the network prioritize, schedule, and allocate resources for different uplink traffic flows. This ensures that critical traffic, such as voice and video calls, receives higher priority, lower latency, and lower packet loss, while non-time-sensitive data services are treated with lower priority, allowing them to share resources more fairly.

Dynamic Provisioning of UL TFTs:

In 5G NR networks, UL TFTs can be dynamically provisioned to support service-based QoS management. This means that when a new service or application is initiated on the device, the network can automatically establish a corresponding UL TFT with appropriate QoS parameters to handle the uplink traffic for that service.

Conclusion:

The Uplink Traffic Flow Template (UL TFT) is a key element in QoS management for uplink data transmission in mobile communication networks like LTE and 5G NR. By defining traffic filters and QoS parameters for different uplink traffic flows, the UL TFT ensures that various applications and services receive the appropriate treatment and resources, meeting their individual QoS requirements and enhancing the overall user experience.