In-Vehicle Network Switch IC Routing Delay and Heat
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Solution Overview
Problem
In-vehicle networks face delays due to software-controlled IP routing operations in network switches, which can lead to increased heat generation from high-performance microcomputers and high-speed communication interfaces.
Innovation Solution
A network switch with a switch IC that includes L2 and L3 receivers and processors, along with memories for MAC address and routing tables, performs IP routing operations independently, reducing the need for high-performance microcomputers and high-speed interfaces, thereby minimizing delay and heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If IP routing operations are performed by software control on a microcomputer, then routing flexibility is improved, but processing delay increases and heat generation increases
Solution Approach 1:
The patent segments the network switch into two functional parts: a switch IC that handles time-critical frame forwarding operations, and a microcomputer that handles higher-level routing decisions. This segmentation allows the microcomputer to perform flexible routing operations without being constrained by real-time forwarding delays, as the switch IC independently handles time-sensitive packet switching.
Solution Approach 2:
The patent introduces an intermediary mechanism where the switch IC acts as a mediator between incoming frames and the microcomputer. The switch IC receives frames, performs initial processing, and only forwards frames requiring routing decisions to the microcomputer, thereby reducing the microcomputer's processing burden and overall system delay.
2Speed
If high-performance microcomputers and high-speed communication interfaces are used to reduce delay, then processing speed is improved, but heat generation increases
Solution Approach 1:
The switch IC is designed to be self-sufficient for handling time-critical frame forwarding operations without requiring high-performance microcomputer intervention. By embedding the switching function directly in dedicated hardware, the system achieves high-speed processing without the heat generation associated with high-performance general-purpose processors.
Solution Approach 2:
The patent replaces the mechanical/software-based routing approach with a hardware-based switching mechanism in the switch IC. This substitution of dedicated hardware for software-controlled processing enables high-speed operation with lower power consumption and heat generation, as hardware switching operates at wire speed without software overhead.
3Adaptability or versatility
If software-controlled routing operations are used, then routing adaptability is improved, but electromagnetic noise emissions increase
Solution Approach 1:
The patent segments routing functionality from frame forwarding operations, placing routing logic in the microcomputer and forwarding logic in the switch IC. This segmentation allows routing adaptability to be maintained through software while reducing electromagnetic noise by isolating high-speed hardware switching from software processing operations.
Data Source
AI summary
A network switch provides an in-vehicle network, and includes a switch IC having multiple ports and a microcomputer. The switch IC includes: L2 and L3 receivers; first and second memories for storing MAC address and routing tables, respectively; and L2 and L3 processors. The L2 receiver determines whether a destination MAC address in a frame is a network switch address. The L2 processor determines a port corresponding to the destination MAC address based on the MAC address table when the destination MAC address is not the network switch address. The L3 receiver determines whether a transmission source IP address is registered in the routing table when the destination MAC address is the network switch address. The L3 processor determines an output port and another destination MAC address of a forwarding destination based on the routing table and a destination IP address when the transmission source IP address is registered.