In my first blog post on purpose built switches, I discussed the robust hardware design of our industrial ethernet switches that enables them to withstand harsh environments. In this blog, we will discuss frequently asked questions with the manager of the hardware team responsible for our robust hardware design.

I have a lot of respect for our hardware team. With collective engineering experience of 100+ years the team has worked multiple generations of Industrial switches as well as industrial routers. The products they design and build come in many shapes and sizes. No two are the same. The requirements and the market are constantly evolving. I have come to appreciate their skill, professionalism, hard work, and dedication. This team is a huge reason why Cisco’s Industrial Ethernet products are best in the market.

After the Q&A session, my primary takeaway is: experience matters!

The picture below represents the work of the Industrial Ethernet switching hardware team.


Q: What is your current job at Cisco?

Manager of Cisco’s IoT Mechanical Engineering team. Prior to managing the team, I was a mechanical engineer for IE switching and industrial routing products.

Q: For our audience, what are the fundamental differences between building/designing hardware for industrial deployments versus enterprise or service provider markets?

The fundamental difference I think in designing for the industrial deployments is the level of “Ruggedization” that we must incorporate into the design. This typically involves designing for harsh environmental conditions such as extreme temperature, high levels of vibration and shock as well as various levels of water/weather proofing. For our products to meet these conditions, attention to detail in our mechanical and thermal design is imperative. Multiple rounds of design simulation and testing are necessary to achieve a successful design.

Q: What is it about Cisco’s process that enables high quality hardware?

Our overall design process is structured to ensure a high-quality product. From a mechanical design process, this involves design simulation and informal prototyping early in the development cycle to have high confidence in the initial design. As the product design cycle continues, additional rounds of design review and validation are performed. Specific validation is dictated by a formal product requirements document that states exactly what compliance standards are required. Finally, there are formal reviews where all testing results are documented and certified as passing before the product can officially release to a production state. The overall process of this design flow ensures that high quality design standards are maintained.

Q: What is Cisco’s approach to meeting the long list of standards and compliance requirements?

During our mechanical design verification testing (MDVT), each new product design will go through a suite of tests focusing on temperature, vibration, and shock parameters. The actual details for each test come from the IEC, SAE, and other industry standard requirements detailed in our product requirements specifications.

Q: The hardware development team has developed multiple generations of industrial Ethernet switching products. What does all the experience bring to the development of industrialized hardware?

Within our IoT mechanical design team we have a collective 100+ years of engineering experience. With such a depth and breadth of technical expertise, we embrace the ever-changing technical challenges that are thrown our way. Within our team we have engineers specialized in key technical areas such as ingress protection design, material selection for corrosive environments, thermal design for natural convection environments and solar loading, as well as many other key areas. Having the expertise in these areas allows us to take on any product design challenge that comes our way and keep Cisco’s product lineup among the best in the Industrial IoT market space.

Q: without giving away any Cisco proprietary information, can you describe the special considerations that go into the hardware design process for thermal or other types of ruggedization?

Overall mechanical ruggedization and thermal design encompass the main functions in our group. To ensure a very robust enclosure design we typically cycle prototype level hardware through multiple rounds of industry standard shock, vibration, and drop testing. In addition, we pay close attention to form factor optimization, material selection, and internal layout to keep product size, weight, and costs competitive and within our budgets. For products intended for outdoor deployment we again look closely at paint and material choice as well as internal gasket design. Our outdoor products are typically rated for IP67 which allows them to maintain functionality in water at a depth of up to 1 meter for 30 minutes. Another design requirement for outdoor deployment is salt fog resistance. To be compliant in this area, special consideration needs to be given to material selection and surface treatment as well as paint selection and thickness. One of our final design considerations is thermal/heat management. This design area has become increasingly challenging given the fact that we must design to industrial grade temperature ranges (-40 to 75C) coupled with the fact that we cannot use cooling fans in our products since they need to remain sealed and unvented in most cases. Due to these constraints, we rely on natural convection and conduction to remove heat. Our thermal design process begins with simulation utilizing computational fluid dynamics (CFD) software. In these simulations we iterate the design until we have something optimized that meets our requirements. After simulation we move on to building prototypes that are thoroughly tested under extreme temperature ranges. Typically, internal enclosure thermal management is required. This will involve individual heat sink and heat spreader design, thermal interface material selection as well as optimized board level layout decisions that allow for a successful design. The design process that we have put in place and outlined above has allowed us to introduce numerous award-winning products into the competitive IoT product landscape and helped Cisco become an industry leader in this space.

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