INT-Assisted Adaptive Packet Scheduling in PDP Switches for End-to-End Latency Control

In today's Internet, ensuring the end-to-end (E2E) latency of delay-sensitive flows is becoming increasingly challenging due to the rapid growth of network services, users and traffic volume. In this work, we propose a packet scheduling scheme that leverages in-band network telemetry (INT) to catch packets' forwarding status in realtime and realizes fine-grained and adaptive packet scheduling accordingly for E2E latency control, and implement it in P4-based programmable data plane switches (PDP-SWs), Specifically, we use INT to make a packet convey its own realtime status (e.g., experienced latency) as it traverses the network, and program PDP-SWs in the network to schedule the packet with the weighted round-robin (WRR) approach based on the realtime status, such that the packet's quality-of-service (QoS) demand on E2E latency can be satisfied in the most effective way. We design the packet processing procedure in PDP-SW, propose an effective packet scheduling algorithm, and optimize the algorithm to ensure that it can be realized with P4 programs. The proposed scheme is then implemented and evaluated in a real-world network testbed built with hardware PDP-SWs. Experimental results confirm the effectiveness of our proposal and suggest that it achieves better control of E2E latency than a few existing benchmarks.