Cisco IE 3000, Руководство по настройке программного обеспечения

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C H A P T E R
9-1
Cisco IE 3000 Switch Software Configuration Guide
OL-13018-03
9
Configuring PTP
This chapter describes how to configure the Precision Time Protocol (PTP) on the Cisco IE 3000 switch.
•
Understanding PTP, page 9-1
• Configuring PTP, page 9-1
•
Displaying the PTP Configuration, page 9-4
Understanding
PTP
The Precision Time Protocol (PTP), as defined in the IEEE 1588 standard, synchronizes with
nanosecond accuracy the real-time clocks of the devices in a network. The clocks are organized into a
master-member hierarchy. PTP identifies the switch port that is connected to a device with the most
precise clock. This clock is referred to as the master clock. All the other devices on the network synchronize
their clocks with the master and are referred to as members. Constantly exchanged timing messages ensure
continued synchronization.
PTP is particularly useful for industrial automation systems and process control networks, where motion
and precision control of instrumentation and test equipment are important.
You can globally configure the switch to pass PTP packets through the switch as normal multicast traffic
(forward mode), to synchronize all switch ports with the grand master clock (end-to-end transparent mode),
or you can configure boundary clock mode, where the switch participates in selecting the best master clock
and can act as the master clock if no better clocks are detected.
When the switch is in PTP forward or end-to-end transparent mode, no PTP configuration is available
except configuring PTP mode to another mode. You can only configure per-port PTP when the switch is
in boundary mode.
Configuring PTP
• Default Configuration, page 9-2
•
Setting Up PTP, page 9-3