ITSY: Initial Trigger-Based PFC Deadlock Detection in the Data Plane

Lossless networks are increasingly popular for high-performance applications in data centers and cloud environments. To realize a lossless network in Ethernet, the Priority-based Flow Control (PFC) protocol is adopted to guarantee zero packet loss. PFC, however, can induce in-network deadlocks and in severe cases cause the entire network to be blocked. Existing solutions have focused on deadlock avoidance strategies; unfortunately, they are not foolproof. Therefore, deadlock detection is a necessity. In this paper, we propose ITSY, a novel system that correctly detects and solves deadlocks entirely in the data plane. It does not require any assumptions on network topologies and routing algorithms. Unique to ITSY is the use of deadlock initial triggers, which contributes to efficient deadlock detection and deadlock recurrence prevention. We implement ITSY for programmable switches in the P4 language. Preliminary evaluations demonstrate that ITSY can detect deadlocks rapidly with minimal overheads and mitigate the recurrence of the same deadlocks effectively.