Broadcom BroadView Instrumentation

The diagram above, from the BroadView™ 2.0 Instrumentation Ecosystem presentation, illustrates how instrumentation built into the network Data Plane (the Broadcom Trident/Tomahawk ASICs used in most data center switches) provides visibility to Software Defined Networking (SDN) controllers so that they can optimize network performance.

The sFlow measurement standard provides open, scaleable, multi-vendor, streaming telemetry that supports SDN applications. Broadcom has been augmenting the rich set of counter and flow measurements in the base sFlow standard with additional metrics. For example, Broadcom ASIC table utilization metrics, DevOps, and SDN describes metrics that were added to track ASIC table resource consumption.

The highlighted Buffer congestion state / statistics capability in the slide refers to the BroadView Buffer Statistics Tracking (BST) instrumentation. The Memory Management Unit (MMU) is on-chip logic that manages how the on-chip packet buffers are organized.  BST is a feature that enables tracking the usage of these buffers. It includes snapshot views of peak utilization of the on-chip buffer memory across queues, ports, priority group, service pools and the entire chip.

The above chart from the Broadcom technical brief, Building an Open Source Data Center Monitoring Tool Using Broadcom BroadView™ Instrumentation Software, shows buffer utilization trended over an hour.

While the trend chart is useful, the value of BST instrumentation is fully realized when the data is integrated into the sFlow telemetry stream, allowing buffer utilizations to be correlated with traffic flows consuming the buffers. Broadcom's recently published sFlow extension, sFlow Broadcom Peak Buffer Utilization Structures, standardizes the export of the buffer metrics, ensures multi-vendor interoperability, and providing the comprehensive, actionable, telemetry from the network required by SDN applications.

Ask switch vendors about their plans to support the extension in their sFlow implementations. The enhanced visibility into buffer utilization addresses a number of important use cases:

• Fabric-wide visibility into peak buffer utilization
• Derive worst end to end case latency
• Pro-actively track microbursts and identify hot spots before packets are lost
• Correlate with traffic flows and link utilizations
• Improve performance through QoS marking, load spreading, and workload placement