so much so that a time-aware Bridge with Ethernet ports can be shown to be mathematically equivalent to a P2P transparent
clock in terms of how synchronization is performed.
1. Time-aware end station
An end station that is capable of acting as the source of synchronized time on
the network, or destination of synchronized time using the IEEE 802.1AS protocol, or both.
2. Time-aware bridge
A Bridge that is capable of communicating synchronized time received on one
port to other ports, using the IEEE 802.1AS protocol.
5.4 linuxptp stack
Features of open source linuxptp
• Supports hardware and software time stamping via the Linux SO_TIMESTAMPING socket option.
• Supports the Linux PTP Hardware Clock (PHC) subsystem by using the clock_gettime family of calls, including the
clock_adjtimex system call.
• Implements Boundary Clock (BC), Ordinary Clock (OC) and Transparent Clock (TC).
• Transport over UDP/IPv4, UDP/IPv6, and raw Ethernet (Layer 2).
• Supports IEEE 802.1AS-2011 in the role of end station.
• Modular design allowing painless addition of new transports and clock servos.
• Implements unicast operation.
• Supports a number of profiles, including:
— The automotive profile.
— The default 1588 profile.
— The enterprise profile.
— The telecom profiles G.8265.1, G.8275.1, and G.8275.2.
— Supports the NetSync Monitor protocol.
• Implements Peer to peer one-step.
• Supports bonded, IPoIB, and vlan interfaces.
Features added by OpenIL
• Supports IEEE 802.1AS-2011 in the role of time-aware bridge.
• Supports synchronization to LS1021ATSN SJA1105 switch with sja1105-tool APIs.
5.5 Quick Start for IEEE 1588
5.5.1 Ordinary clock verification
Connect two network interfaces in back-to-back manner for two boards. Make sure there is no MAC address conflict on the
boards, the IP addresses are set properly and ping the test network. Run
linuxptp
on each board. For example,
eth0
is used
on each board.
$ ptp4l -i eth0 -m
NXP Semiconductors
IEEE 1588/802.1AS
Open Industrial User Guide, Rev. 1.8, 05/2020
User's Guide
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