Maximizing SAI Potential with Testing
Switch Abstraction Interface (SAI) facilitates the codesign of network devices. Figure 1 below illustrates an example of how a data center switch architecture is built around SAI. It enables bringing best in class components into each building block of the architecture to create a custom solution fit for each use case. SAI is a critical layer. ASIC and switch vendors are building SAI compliant devices; the network operators can consume these devices easily and deploy their choice of Network Operating System (NOS) on it.
SONiC is an example of such a NOS which saw huge adoption in cloud data centers. Facebook open switching system (FBOSS) is another example of such a NOS used by Meta that is built atop SAI.
Figure 1: Data center switch disaggregation and SAI (Source: Keysight)
SAI is a sub-project of the Open Compute Project (OCP), acting as the glue that brings the vendors and consumers together, thereby enabling choice with open networking components.
The SONiC-DASH project also recently adopted SAI. The DASH program is enabling data processing units (DPUs) or Smart NICs to run SONiC. The end goal is creating a smartTOR to offload servers in cloud data centers, with SAI becoming an obvious choice for this project as well.
When it comes to testing SAI, there are some tools available like the SAI-PTF framework. However, it is limited to packet-based testing with no path to expand or reuse the test into a system test environment. Because current SAI test methodologies have limitations, defects and regressions are caught later in the development cycle (e.g., at the system level), causing delays and increasing costs. There is an urgent need to perform more exhaustive testing earlier in the cycle and SAI testing is the clear choice for this early verification.
Keysight developed Open Traffic Generator (OTG), an open standard, and completely vendor neutral API for testing Layer 2-7 network devices and applications (at any scale). Like open networking, OTG brings choice to the community. We offer options for traffic generation and protocol emulation, ranging from a free, SW-based community version, all the way up to commercial, high-performance, hardware-based platforms. OTG gives the power of flow-based traffic testing and advanced statistics with the promise of writing the test once and running it all the way from containerized test agents (Ixia-c) to flagship Keysight Ixia traffic generators (AresONE, Novus etc.).
This is a perfect fit for SAI testing. Taking the shift-left approach, Ixia-c can enable a developer environment with test capabilities. The same test can now run in emulation all the way up to wire speed of 100/400/800GE and so on. High speed Ethernet is a fast-moving target with data center refresh cycles shortening. The need to move testing into different form-factors is becoming extremely critical for faster time to market . Testing at each layer expedites that. At the same time, test tools need to be an order of magnitude faster than before, to keep up with the demanding pace of development. OTG is lean by design, enabling much faster test cycles than traditional tools.
A very recent collaboration with PLVision integrated OTG into SAI Challenger to enhance SAI testing for the benefit of SONiC-DASH. PLVision initially developed SAI Challenger, an open solution and was a contributor to OCP in 2021. Today the DASH project CI pipeline is using SAI Challenger to test the behavioral model (bmv2) for DASH with every change. This is a classic case of multiple companies coming together to codesign a solution for the community. You can extend these tests to work on switches or any SAI implementations for that matter.
Figure 2:OTG integration into SAI-Challenger (Source: Keysight whitepaper)
Chris Sommers, Distinguished SW Engineer, Keysight Technologies, discusses this use case in detail in this whitepaper.
Figure 3: Read the white paper HERE
Keysight continues to deliver innovative solutions by identifying new use-cases and developing content for testing SAI. OTG integration with SAI Challenger yields an unbeatable combination of flexibility and scale, supporting a full range of traffic generators from the community version of Ixia-c up to 800GE line rate testers.
Contribute to our open traffic generator journey at https://otg.dev/