Sign in Subscribe

RQI (reflective QoS indication)

Last updated on 


Reflective QoS Indication (RQI) is a mechanism used in computer networks to provide feedback on the quality of service (QoS) experienced by network packets. It allows network devices to reflect the QoS treatment received by packets back to the sender, enabling them to adapt their behavior accordingly.

The main purpose of RQI is to allow the sender to monitor and react to changes in the network conditions and adjust the transmission parameters or the data being sent based on the observed QoS. By receiving feedback on how packets are being treated in the network, the sender can make informed decisions to optimize the performance and resource utilization.

Here's a step-by-step explanation of how RQI works:

  1. Sender initiates packet transmission: The sender node (e.g., a computer or network device) sends packets into the network for delivery to the destination.
  2. Network devices apply QoS treatment: As the packets traverse the network, various intermediate network devices such as routers or switches may apply QoS mechanisms to prioritize, shape, or police the traffic based on predefined policies. These mechanisms can include traffic prioritization, rate limiting, congestion avoidance, or traffic shaping.
  3. Reflective QoS marking: Along the packet's path, network devices that support RQI inspect and modify the packet's header to include reflective QoS markings. These markings convey information about the QoS treatment received by the packet during its journey.
  4. Packet reaches destination: The packet eventually arrives at its destination node.
  5. Destination inspects reflective QoS markings: Upon receiving the packet, the destination node inspects the reflective QoS markings in the packet's header to determine how the packet was treated during transit.
  6. Feedback sent back to sender: The destination node generates feedback information based on the observed QoS treatment and sends it back to the sender.
  7. Sender adapts transmission behavior: The sender receives the feedback information and can adapt its transmission behavior accordingly. For example, if the feedback indicates that packets were dropped due to congestion, the sender might reduce the transmission rate or adjust the congestion control algorithm. If the feedback indicates successful delivery, the sender might increase the transmission rate or adjust the payload size.

By leveraging RQI, the sender can dynamically react to changing network conditions, improving the overall QoS experienced by the transmitted data. It enables congestion control, bandwidth allocation, and optimization techniques to be more responsive, leading to enhanced network performance and resource utilization.

It's worth noting that RQI is typically implemented using protocols or mechanisms such as Explicit Congestion Notification (ECN) or Differentiated Services (DiffServ), where network devices modify packet headers with QoS-related information. The specific details of RQI implementation may vary depending on the networking technology or protocol being used.