• PTM Responders must populate PTM ResponseD Messages as follows (refer to Figure 6-24 and the accompanying implementation note): ◦ The PTM Master Time field is a 64-bit value containing the value of PTM Master Time at the receipt of the PTM Request Message for the current PTM Dialog. In Figure 6-24 , for the 2nd PTM dialog, this is the PTM Master Time at time t2’. ◦ The Propagation Delay field is a 32-bit value containing the interval between the receipt of the PTM Request Message and the transmission of the PTM Response Message for the previous PTM dialog. In Figure 6-24 , for the 2nd PTM dialog, this is the time interval between t2 and t3 captured during the 1st PTM dialog. ◦ The unit of measurement for both fields is one ns. ◦ A PTM Responder with multiple Downstream Ports must populate all PTM ResponseD Messages with values from a single PTM Root across all its PTM Ports Downstream ports. 翻译

• PTM Responders 必须按照以下方式填充 PTM ResponseD Messages（参考图 6-24 和相应的实现说明）： ◦ PTM Master Time 字段是一个 64 位值，包含当前 PTM Dialog 的 PTM Master Time 值。在图 6-24 中，对于第二个 PTM dialog，这是 t2' 时刻的 PTM Master Time。 ◦ Propagation Delay 字段是一个 32 位值，包含收到 PTM Request Message 和发送前一个 PTM dialog 的 PTM Response Message 之间的间隔。在图 6-24 中，对于第二个 PTM dialog，这是在第一个 PTM dialog 期间捕获的 t2 和 t3 之间的时间间隔。 ◦ 两个字段的单位均为 1 ns。 ◦ 具有多个 Downstream Ports 的 PTM Responder 必须使用来自单个 PTM Root 的值填充所有 PTM Ports Downstream 端口上的所有 PTM ResponseD Messages。

相关问题

• A PTM Responder must issue PTM ResponseD when it has stored copies of the values required to populate the PTM ResponseD Message: historical timestamps (t3 - t2) and the PTM Master Time at the receipt of the most recent PTM Request Message (time t2’). • A PTM Responder is permitted to issue PTM Response when it has stored copies of the historical timestamps (t3 - t2) but must request the PTM Master Time from elsewhere. In this case, it is permitted to issue PTM Response messages in response to PTM Request Messages while it retrieves the PTM Master Time if that retrieval is expected to take more than 10 μs. • The perceived granularity of the historical timestamps and PTM Master Time values transmitted by a PTM Responder must not exceed that reported in the Local Clock Granularity field of the PTM Capability register. 翻译

• 当 PTM 响应者已经存储了填充 PTM ResponseD 消息所需的值，包括历史时间戳（t3 - t2）和在收到最近的 PTM 请求消息时的 PTM 主时间（时间 t2'）时，必须发出 PTM ResponseD。
• 当 PTM 响应者已经存储了历史时间戳（t3 - t2），但需要从其他地方请求 PTM 主时间时，可以发出 PTM Response 消息。在这种情况下，如果检索所需的 PTM 主时间需要超过 10 微秒，则可以在响应 PTM 请求消息时发出 PTM Response 消息。
• PTM 响应者传输的历史时间戳和 PTM 主时间值的感知粒度不能超过 PTM Capability 寄存器中报告的本地时钟粒度字段。

• Switch Downstream Ports and Root Ports acting as PTM Responders must respond to each PTM Request Message received at their Downstream Ports with either PTM Response or PTM ResponseD according to the following rules: ◦ A PTM Responder must not send a PTM Response or PTM ResponseD Message without first receiving a PTM Request Message. ◦ Upon receipt of a PTM Request Message, a PTM Responder must attempt to issue a PTM Response or PTM ResponseD Message within 10 μs. ◦ A PTM Responder must issue PTM Response when the Downstream Port does not have valid historical timestamps (t3 - t2) with which to fulfill a PTM Request Message. 翻译

• 作为 PTM Responders 的 Switch Downstream Ports 和 Root Ports 必须根据以下规则响应其收到的每个 PTM Request Message，使用 PTM Response 或 PTM ResponseD： ◦ PTM Responder 必须在先收到 PTM Request Message 后才能发送 PTM Response 或 PTM ResponseD Message。 ◦ 在收到 PTM Request Message 后，PTM Responder 必须在 10 微秒内尝试发出 PTM Response 或 PTM ResponseD Message。 ◦ 当 Downstream Port 没有有效的历史时间戳（t3 - t2）来满足 PTM Request Message 时，PTM Responder 必须发出 PTM Response。