Dr. Evil is right, lasers are cool! The draft sFlow Optical Interface Structures specification exports metrics gathered from instrumentation built into Small Form-factor Pluggable (SFP) and Quad Small Form-factor Pluggable (QSFP) optics modules. This article provides some background on optical modules and discusses the value of including optical metrics in the sFlow telemetry stream exported from switches and hosts.
The bottom half of the diagram shows the management components. Power, voltage and temperature sensors are monitored and the results are written into registers in an EEPROM that are accessible via a management interface.
The proposed sFlow extension standardizes the export of the module sensor data so that they can be exported along with switch port interface counters. A standard structure ensures multi-vendor interoperability and including the optical metrics as part of the sFlow export provides a scaleable method of monitoring all the optical modules in the network.
counter push mechanism is an extremely efficient method of monitoring at scale and can collect metrics from all the optical modules in the data center. Combining data from all the modules makes it easier to find outliers.
comprehensive sFlow telemetry stream allows optical metrics to be correlated with switch port, traffic flow and application performance metrics. For example, an increase in application response time can be traced to the paths that the traffic takes across the network, packet discard rates on the ports, and signal strength from the optical sensors, to find a marginal fiber link.