Optical RF Tone In-Band Labeling for Large-Scale and Low-Latency Optical Packet Switches

Abstract

We propose an RF tone in-band labeling technique that is able to support large-scale and low-latency optical packet switch. This approach is based on N in-band wavelengths, each carrying M radio frequency (RF) tones. The wavelengths and the tones have a binary value, and are able to encode 2 N M possible routing address. We develop an optical label processor for the RF tone in-band optical label based on parallel and asynchronous processing. It allows the optical packet switch with an exponential increase of number of ports at the expense of limited increase in the latency and the complexity. By using RF tone in-band labeling technique, we demonstrate error free (bit error rate 10 9 ) optical packet switching operation for both 160 Gb/s packets and 40 Gb/s packets. We further investigate the scalability, the latency and the optical power fluctuation tolerance of the proposed RF tone in-band labeling technique. We show that 30 label bits are able to be delivered using single in-band wavelength, and the label processor introduces an extra latency of less than 7 ns.Index Terms-Label processor, optical labeling, optical packet switching, RF tone in-band label.

Novel flat datacenter network architecture based on scalable and flow-controlled optical switch system

“…RF tone in-band labeling technique and bi-directional optical system are deployed to efficiently transmit the label and ACK in a single fiber. Such labeling technique allows the parallel processing of the label bits which will greatly reduce the OPS processing time [14]. Here we use two RF tones (f1 = 284.2MHz, f2 = 647.1MHz) for coding the 2-bit binary label information.…”

“…Packetized data will be assigned with different wavelength λ 1 , λ 2 …, λ M and transmitted to OPS node. Switching is performed based on the in-band label information carried by each packet [14]. After the packet being sent out, aggregation controller will store the copy in a FIFO until receiving a positive acknowledgment that the packet has been transported to proper destination.…”

Low latency and efficient optical flow control for intra data center networks

“…For the proof of a 4 × 4 switch system, each label wavelength carries two binary coded RF tones. The number of tones can potentially scale up to at least 30 which will represent a large number of ports with constant processing time [11]. Figure 3(a) illustrates the electrical spectrum of the two RF tones (f1 = 280MHz, f2 = 650MHz) of the label we used in this experiment.…”

“…The optical packets consisting of synchronized data payload and in-band RF tone label signal are transmitted to OPS node. The advantage of the in-band RF tone label technique is that it saves bandwidth resources and since label wavelength carries several binary coded RF tones, parallel processing for each bit is allowed which greatly reduce the OPS processing time to few nanoseconds regardless of the bit-count [11]. RF tones are placed at high-frequency region (>100MHz) while the base-band is virtually empty (employed to transmit back the ACK signal).…”

Numerical and experimental study of a high port-density WDM optical packet switch architecture for data centers

“…The labels are O-E converted and processed by the switch controller. The employed parallel in-band labeling processing technique with few nanoseconds operation regardless the bit-count has been presented in [10]. The packet payloads remain in the optical domain and are fed into the 1xN BS.…”