PMD Circuitry Link Training Deadlock Prevention
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Solution Overview
Problem
Existing link training protocols, such as those using IEEE 802.3 Clause 136.8.10 PMD control function state machines, can lead to deadlock conditions during link establishment, resulting in failed link establishment and prolonged times to achieve a stable link.
Innovation Solution
Implementing a check during TRAIN_LOCAL and TRAIN_REMOTE states to exit to a TIMEOUT state earlier if conditions such as loss of local_tf_lock, remote_tf_lock, or expiration of a max_wait_timer are met, thereby reducing the likelihood of deadlock and facilitating quicker link re-establishment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing link training protocols using IEEE 802.3 Clause 136.8.10 PMD control function state machines are used, then link training can be performed, but deadlock conditions occur during link establishment resulting in failed link establishment and prolonged times to achieve a stable link
Solution Approach 1:
The patent applies preliminary action by checking lock status conditions (local_tf_lock and remote_tf_lock) before proceeding with extended training sequences. The system proactively detects potential deadlock conditions by monitoring whether training frame markers can be identified and decoded, and exits the training state early if these conditions are not met, preventing wasted time in注定 failed training sequences
Solution Approach 2:
The patent implements feedback mechanisms by continuously monitoring training frame decoding status and lock conditions during link training. The system uses feedback from the ability to identify training frame markers and decode training data to determine whether to continue or exit training, creating a closed-loop control that adapts to actual link conditions and avoids deadlock states
2Manufacturing precision
If link training continues extended periods to ensure proper establishment, then more thorough training can be achieved, but deadlock conditions and prolonged timeouts increase
Solution Approach 1:
The patent applies preliminary action by establishing early exit conditions based on lock status before committing to extended training sequences. By checking whether training frame markers can be identified and decoded at the outset, the system determines in advance whether continued training is likely to succeed, avoiding prolonged training in conditions注定 to fail while maintaining thorough training when conditions are favorable
Data Source
AI summary
Examples described herein relate to a network interface comprising physical medium dependent (PMD) circuitry, the PMD circuitry to during link training of at least one lane consistent with IEEE 802.3, exit to TIME_OUT state during TRAIN_LOCAL state based on consideration of expiration of a wait timer, loss of local_tf_lock state, and loss of remote_tf_lock state. In some examples, during link training for at least one lane consistent with IEEE 802.3, the PMD circuitry is to exit to TIME_OUT state during TRAIN_REMOTE state based on consideration of expiration of a wait timer, loss of local_tf_lock state, and loss of remote_tf_lock state. In some examples, link training consistent with IEEE 802.3 comprises performance of the PMD control function in Section 162.8.11 of IEEE 802.3ck.