What is TAD (traffic aggregate description)

In the realm of mobile communication networks, particularly LTE (Long-Term Evolution) and its derivatives, Traffic Aggregate Description (TAD) plays a vital role in managing data traffic flow. It acts as a message that conveys information about packet filters to be applied to a specific traffic aggregate within the network.

Understanding Traffic Aggregates:

• Cellular networks handle various types of data traffic, such as voice calls, video streaming, and web browsing. These different traffic types might have varying requirements for quality of service (QoS).
• A traffic aggregate refers to a group of data flows that share similar characteristics and QoS requirements. By grouping traffic, the network can manage resources more efficiently and prioritize different types of data flows as needed.

The Role of TAD:

• The TAD message essentially defines the packet filters that should be applied to a specific traffic aggregate. These filters act as instructions for the network elements (e.g., gateways, routers) on how to handle the data packets within that aggregate.

What a TAD Message Contains:

• Traffic Aggregate Identifier: This unique identifier specifies the particular traffic aggregate to which the filters apply.
• Packet Filter Information: This section details the specific criteria for filtering data packets. Criteria can include:
  • Source and destination IP addresses
  • Port numbers
  • Protocol type (e.g., TCP, UDP)
  • Packet size limitations
• QoS Parameters: The TAD might also include parameters related to the desired QoS for the traffic aggregate, such as:
  • Priority level
  • Guaranteed Bit Rate (GBR)
  • Maximum Packet Delay Budget (MPD)

How TAD is Used:

1. UE (User Equipment) Request: The User Equipment (e.g., smartphone) initiates a data transfer request. This request might specify the type of traffic (e.g., video streaming) and the desired QoS.
2. Network Attachment & TAD Creation: Upon attaching to the network, the UE and the network negotiate the appropriate traffic aggregate for the requested data flow. The network then creates a TAD message containing the relevant packet filters and QoS parameters for that specific aggregate.
3. TAD Distribution: The TAD message is disseminated through the network to the entities responsible for handling the data flow (e.g., gateways, routers).
4. Packet Filtering & QoS Enforcement: Based on the TAD instructions, network elements filter data packets and prioritize them according to the defined QoS parameters, ensuring efficient resource allocation and optimized data transfer for the specific traffic aggregate.

Benefits of TAD:

• Improved Traffic Management: TAD facilitates efficient traffic management by grouping data flows with similar characteristics and applying suitable filters and QoS parameters.
• Prioritization: TAD allows prioritizing traffic flows based on their importance. For example, a video call might be prioritized over a background download to ensure smooth communication.
• Optimized Network Performance: By managing traffic efficiently, TAD contributes to improved overall network performance, minimizing congestion and latency.

Conclusion:

Traffic Aggregate Description (TAD) serves as a crucial element in LTE and similar cellular networks. By conveying information about packet filters and QoS requirements, TAD empowers the network to manage data traffic effectively, prioritize different types of data flows, and ultimately deliver a seamless and optimized user experience.