Orthogonal Optics Switch Layout for Shorter 224G Signal Paths
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Solution Overview
Problem
Existing network switch designs face challenges in achieving high-speed electrical data transmission above 200 Gbps using printed circuit board traces due to increased signal loss and trace length, necessitating costly alternatives like flyover cables or on-board optics, which also compromise airflow and serviceability.
Innovation Solution
A network switch design with orthogonal pluggable optics modules mounted on the switch PCB, allowing for shorter electrical connections and efficient airflow cooling, eliminating the need for costly alternatives by minimizing trace length and improving cooling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the data rate of electrical lanes is doubled from 112 to 224 Gbps, then the signaling speed is improved, but the signal loss increases and the electrical signal reach is reduced
Solution Approach 1:
The patent transitions from planar PCB traces to three-dimensional coaxial cable routing, allowing electrical connections to extend vertically and diagonally through the chassis. This dimensional change enables longer connection lengths (up to 40 inches) without proportionally increasing signal loss, as the coaxial cable structure provides superior shielding and lower attenuation compared to flat PCB traces.
Solution Approach 2:
The patent introduces coaxial cables as an intermediary component between the switch chip and interface ports, replacing direct PCB trace connections. These cables act as a mediator that maintains signal integrity at high speeds by providing controlled impedance, shielding from interference, and lower insertion losses over extended distances.
2Loss of energy
If coaxial cables are used to connect switch chip to interface ports, then the signal loss is reduced, but the manufacturing complexity and cost increase
Solution Approach 1:
The patent divides the electrical connection system into separate functional segments: the switch chip on the circuit board, the coaxial cable connections, and the interface ports. This segmentation allows each component to be optimized independently and enables modular assembly, where pre-assembled cable assemblies can be integrated into the chassis in a standardized manner.
Solution Approach 2:
The patent employs pre-assembled coaxial cable assemblies with connectors already attached, allowing these components to be manufactured and tested separately before final integration into the switch chassis. This preliminary assembly approach simplifies the main manufacturing process and enables quality control at earlier stages.
3Length of stationary object
If on-board optics are used to reduce trace length, then the electrical connection distance is reduced, but the serviceability deteriorates
Solution Approach 1:
The patent employs dynamically replaceable coaxial cable assemblies that can be easily installed and removed from the switch chassis without permanent installation. This dynamic design allows field technicians to replace faulty cable assemblies quickly, improving serviceability compared to permanently soldered on-board optics while still maintaining short effective electrical connection lengths.
4Ease of operation
If the trace length is increased to accommodate conventional switch card layouts, then the interface port accessibility is improved, but the signal loss increases
Solution Approach 1:
The patent utilizes three-dimensional space within the chassis by routing coaxial cables vertically and diagonally, rather than being constrained to the two-dimensional plane of the PCB. This allows interface ports to be positioned at the front panel for easy accessibility while maintaining short effective electrical connection lengths through optimized cable routing paths that minimize signal travel distance.
Data Source
AI summary
The present disclosure describes a network switch design that includes a vertical switch circuit board that is mounted parallel to the front panel of the network switch. The vertical circuit board supports switch chip(s) to process and forward packets and pluggable module connectors to receive pluggable optics modules that provide connections to other network switches. The pluggable module connectors are horizontally oriented to facilitate routing of electrical signal traces. The arrangement of the circuit board, switch chip(s) and pluggable module connectors achieves reduced lengths for the electrical signal traces that connect the switch chip(s) to the pluggable module connectors. The design improves cooling by providing separate airflow regions between the switch chip heatsink(s) and the optics modules.