Cisco: “Experience Matters” IE Switching
In my first blog post on Purpose-Built Switches, I discussed the rugged hardware design of our Industrial Ethernet Switches that allows them to withstand harsh environments. In this blog, we will discuss frequently asked questions with the head of the hardware team responsible for our robust hardware design.
I have a lot of respect for our hardware team. With a collective engineering experience of over 100 years, the team has worked on several generations of industrial switches as well as industrial routers. The products they design and manufacture come in many shapes and sizes. No two are the same. Requirements and the market are constantly changing. I learned to appreciate their skills, professionalism, hard work and dedication. This team is one of the main reasons why Cisco Industrial Ethernet products are the best on the market.
After the Q&A session, my main conclusion is: experience matters!
The image below depicts the work of the Industrial Ethernet switch hardware team.
Q: What is your current job at Cisco?
Lead of the Cisco IoT mechanical engineering team. Before leading 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 and enterprise or service provider markets?
I think the fundamental difference in design for industrial deployments is the level of “reinforcement” we need to incorporate into the design. This typically involves designing for harsh environmental conditions such as extreme temperatures, high levels of vibration and shock as well as varying levels of water and weather tightness. For our products to meet these requirements, attention to detail in our mechanical and thermal design is imperative. Several cycles of design simulation and testing are required to achieve a successful design.
Q: What about Cisco’s process for achieving 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 cycles of design review and validation are performed. The specific validation is dictated by a formal product requirements document that indicates exactly which compliance standards are required. Finally, there are formal reviews where all test results are documented and certified as passed before the product can officially go into production. The overall process of this design flow ensures 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 series of tests focusing on temperature, vibration and shock parameters. The actual details of each test are taken from the requirements of IEC, SAE and other industry standards detailed in our Product Requirements Specification.
Q: The hardware development team has developed several 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 engineering experience of over 100 years. With such depth and breadth of technical expertise, we meet the ever-changing technical challenges thrown at us. Within our team, we have engineers specializing 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 as many other key areas. Our expertise in these areas allows us to meet any product design challenge that comes our way and keep Cisco’s product line among the best in the Industrial IoT market.
Q: Without disclosing any Cisco proprietary information, can you describe any special considerations that go into the hardware design process for thermal or other types of reinforcement?
Overall mechanical robustness and thermal design encompasses the main functions of our group. To ensure a very robust case design, we typically subject prototype-level hardware to multiple rounds of industry-standard shock, vibration, and drop tests. Additionally, we pay close attention to form factor optimization, material selection and internal layout to keep product size, weight and cost competitive and within our budgets. For products intended for outdoor deployment, we again look closely at the choice of paint and materials as well as the design of the internal seal. Our outdoor products are typically IP67 rated, allowing them to maintain functionality in water up to 1 meter deep for 30 minutes. Another design requirement for outdoor deployment is salt spray resistance. To be compliant in this area, particular attention must be paid to material selection and surface treatment as well as paint selection and thickness. One of our final design considerations is thermal/heat management. This area of design has become increasingly difficult as we have to design industrial grade temperature ranges (-40 to 75°C) coupled with the fact that we cannot use cooling fans in our products as they should remain sealed and unventilated in most cases. Due to these constraints, we rely on natural convection and conduction to remove heat. Our thermal design process begins with a simulation using computational fluid dynamics (CFD) software. In these simulations, we iterate the design until we have something optimized that meets our requirements. After the simulation, we move on to building prototypes which are thoroughly tested in extreme temperature ranges. Typically, internal enclosure thermal management is required. This will involve individual heatsink and heatsink design, selection of thermal interface materials as well as optimized layout decisions at the board level that enable a successful design. The design process we implemented and described above has allowed us to introduce many award-winning products into the competitive landscape of IoT products and has helped Cisco become an industry leader in this area.