AVB Network Talker Controller Limp-Home Protocol Switching
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Solution Overview
Problem
Existing automotive networking systems face challenges in efficiently managing data transmission over Ethernet networks, particularly in handling failure conditions and ensuring quality of service for audio and video data streams, which can lead to reduced performance and lack of limp-home modes in case of network failures.
Innovation Solution
The implementation of a module that connects to an Audio Video Bridging (AVB) network, featuring a talker controller that transmits advertisement messages and adjusts data streams to non-AVB streams when AVB reservations fail, ensuring continued data transmission with reduced quality but maintaining functionality, and a listener controller that processes data accordingly to handle AVB and non-AVB streams based on availability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If AVB protocol is used for high-quality audio/video streaming, then data transmission quality is improved, but system reliability deteriorates due to lack of failure handling
Solution Approach 1:
The system dynamically switches between AVB mode and non-AVB mode based on network conditions. The talker controller monitors for failure messages and transitions from high-quality AVB streaming to robust non-AVB streaming when failures are detected, and vice versa when recovery is detected. This dynamic adaptation resolves the contradiction by allowing the system to operate in high-quality mode when possible while maintaining reliability through automatic fallback.
Solution Approach 2:
The system changes the transmission mode parameter from AVB to non-AVB based on network health. When a failure message is received, the talker controller changes the streaming parameter to non-AVB mode, which uses different protocol characteristics that are more tolerant of network failures. This parameter change allows the system to maintain reliability while preserving the ability to achieve high transmission quality when conditions permit.
2Productivity
If AVB streaming is implemented, then data transmission capability is improved, but device complexity increases due to protocol management requirements
Solution Approach 1:
The talker controller automatically monitors the network for failure messages and performs self-diagnosis of AVB streaming health. When a failure is detected, the system automatically switches to non-AVB mode without requiring external intervention or complex manual configuration. This self-service approach reduces device complexity by automating protocol management while maintaining high data transmission capability through intelligent protocol selection.
Solution Approach 2:
The system implements a feedback mechanism where the talker controller receives failure messages from listeners or bridge controllers and uses this feedback to adjust transmission mode. The feedback loop enables automatic adaptation to network conditions, reducing the complexity of manual protocol management while preserving advanced AVB transmission capabilities when conditions are favorable.
3Adaptability or versatility
If protocol switching is implemented across all modules, then adaptability is improved, but manufacturing cost increases
Solution Approach 1:
The talker controller is designed with multi-functionality to support both AVB and non-AVB streaming modes. Rather than requiring separate hardware or complex protocol stacks in all modules, the talker controller universally handles both protocols, switching between them as needed. This universal design improves protocol adaptability while reducing manufacturing costs by avoiding the need for specialized AVB-only or non-AVB-only modules throughout the system.
Solution Approach 2:
The protocol handling capability is segmented and concentrated in the talker controller rather than being distributed across all network modules. The talker controller performs the complex protocol switching and mode selection, while other modules can remain simpler. This segmentation improves overall system adaptability while reducing manufacturing costs by limiting the complexity requirement to a single controller rather than all modules.
Data Source
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AI summary
Electronic modules in a vehicle may communicate over an Audio/Video Bridging (AVB) network. The modules normally cooperate to send and receive streams of data with a specified quality of service as AVB streams. When conditions are present in which an AVB-quality stream cannot be sent over the network, the modules can communicate with certain limp-home functionality. Sending modules may send streams of data without a stream reservation as multicast messages. Receiving modules may be configured to receive the multicast messages. Network bridge modules may be configured to enable a Talker Pruning feature to facilitate handling of the multicast messages.