Related
Documentation
PTP over Ethernet on ACX Series Routers Overview on page 238•
• Guidelines for Configuring PTP over Ethernet on page 240
• Configuring PTP Multicast Master and Slave Ports for Ethernet Encapsulation on
page 274
• Example: Configuring PTP over Ethernet for Multicast Master, Slave, and Dynamic
Ports on page 281
Example: Configuring PTP over Ethernet for Multicast Master, Slave, and Dynamic
Ports
In PTP over Ethernet networks, the master sends the announce, synchronization, and
delay-response packets using the multicast method. If any unicast delay-request message
is received, the master disregards the message and does not send delay-response
messages to the slave. A PTP slave receives the multicast announce packets from the
master or multiple masters and determines the best master using Best Master Clock
Algorithm (BMCA). A slave receives and processes the synchronization from the selected
master clock. The slave sends delay-request messages to this master using the multicast
method and processes the delay-response messages from the master to establish
synchronization.
Both the link-local MAC address and the standard 802.3 multicast MAC address can be
present in a system. However, a PTP interface supports only one of the following at a
point in time:
•
Layer 2 multicast with link-local MAC address
•
Layer 2 multicast with standard multicast MAC address
•
PTP over IPv4
When you configure both IPv4 and Ethernet encapsulation, the unicast-negotiation
configuration applies only to IPv4 encapsulation. It is not effective for PTP over Ethernet
operation.
When you configure a logical interface by using the stateful statement at the [edit
protocols ptp] hierarchy level, each interface that you configure as a stateful or dynamic
port is considered to be both a master and a slave port. Although an ACX Series router
supports up to 32 master ports and 4 slave ports, you can configure only 4 unique logical
interfaces as potential PTP masters by using the stateful statement because the interface
is treated as both a slave and a master interface. You cannot configure the interface that
you specify to be a stateful or dynamic port with the master or slave statements.
This example shows how to configure a master port, slave port, and a dynamic port for
PTP over Ethernet and PTP over IPv4 encapsulation, and how to configure unicast and
multicast mode of transmission of PTP traffic among the master and slave nodes.
•
Requirements on page 282
•
Overview on page 282
281Copyright © 2017, Juniper Networks, Inc.
Chapter 9: Configuring Timing and Synchronization
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