Deterministic passive optical networking
K. Christodoulopoulos, Sarvesh Bidkar, Wolfram Lautenschlaeger, Thomas Pfeiffer, R. Bonk
Abstract
A time-division-multiplexed (TDM) passive optical network (PON) that behaves like multiple point-to-point (P2P) links can support applications with stringent timing requirements while also maintaining the cost benefits of the point-to-multipoint (P2MP) topology. This requires the TDM-PON to provide deterministic performance: lossless transmission and low and constant (with low variations/jitter) latency to selected flows, while also serving other, e.g., best-effort, traffic flows. We demonstrate two approaches for providing deterministic performance over a TDM-PON. In the first approach, we operate the PON asynchronously to its clients and use scheduling that provides upstream bursts at a low and constant period. Jitter compensator gateways (JC GWs) are used to compensate for the jitter introduced by the non-matching PON bursts and the input traffic cycles. In the latter approach, we implement a deterministic dynamic bandwidth allocation (detDBA) process that controls the placement of bursts at each PON frame for selected transmission containers (T-CONTs) that correspond to flows with given traffic profiles. We synchronize and co-schedule the PON with the rest of the network and applications to provide deterministic performance to those flows. As a use case, we study the communication of industrial applications over the deterministic PON system and demonstrate latency below 100 µs and sub-µs packet latency jitter for the industrial flows, while at the same time serving best-effort traffic flows.