Conventions—Intel

®

82599 10 GbE Controller

1.4.10 Time Sync — IEEE 1588 — Precision Time

Protocol (PTP)

The IEEE 1588 International Standard lets networked Ethernet equipment synchronize internal clocks according to a network master clock. The protocol is implemented mostly in software, with the 82599 providing accurate time measurements of special Tx and Rx packets close to the Ethernet link. These packets measure the latency between the master clock and an end-point clock in both link directions. The endpoint can then acquire an accurate estimate of the master time by compensating for link latency. See

Section 7.9

for more details.

The 82599 provides the following support for the IEEE 1588 protocol:

• Detecting specific PTP Rx packets and capturing the time of arrival of such packets in dedicated CSRs

• Detecting specific PTP Tx packets and capturing the time of transmission of such packets in dedicated CSRs

• A software-visible reference clock for the above time captures

1.5 Conventions

1.5.1 Terminology and Acronyms

See Section 15.0

for a list of terminology and acronyms used throughout this document.

1.5.2 Byte Count

When referencing jumbo packet size, 1 KB equals 1024 bytes.

For example:

• 9.5 KB equals 9.5 x 1024 = 9728 bytes

• 15.5 KB equals 15.5 x 1024 = 15872 bytes

1.5.3 Byte Ordering

This section defines the organization of registers and memory transfers, as it relates to information carried over the network:

• Any register defined in big endian notation can be transferred as is to/from Tx and Rx buffers in the host memory. Big endian notation is also referred to as being in network order or ordering.

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