Cisco IE 3000 Software Configuration Guide, Release 12.2(55)SE

Step 1 

configure terminal

Enter global configuration mode.

Step 2 

ptp {mode {boundary | e2etransparent | forward} | priority1 value | priority2 value}

Set the synchronization clock.

•Select boundary mode to enable the switch to participate in selecting the best master clock. If no better clocks are detected, the switch becomes the grandmaster clock on the network and the parent clock to all connected devices. If the best master is determined to be a clock connected to the switch, the switch synchronizes to that clock as a child to the clock, then acts as a parent clock to devices connected to other ports. After initial synchronization, the switch and the connected devices exchange timing messages to correct time skew caused by clock offsets and network delays.

Use this mode when overload or heavy load conditions produce significant delay jitter.

•Select e2etransparent (end-to-end transparent) mode for the switch to synchronize all switch ports with the grand master clock connected to the switch,. This is the default clock mode. The switch corrects for the delay incurred by every packet passing through it (referred to residence time).

This mode causes less jitter and error accumulation than boundary mode.

•Select forward mode for incoming PTP packets to pass through the switch as normal multicast traffic.This disables both boundary and end-to-end transparent mode.

When the switch port is in boundary mode, set the clock priority properties.

•Specify the priority1 value to override the default criteria (clock quality, clock class, etc.) for best master clock selection. Lower values take precedence.The range for both is from 0 to 255. The default is 128.

•Specify a priority2 value to be used as a tie-breaker between two devices that are otherwise equally matched in the default criteria. For example, you can use priority2 value to give a specific switch priority over other identical switches. The range for both is from 0 to 255. The default is 128.

These values set the clock priority on the PTP network for the purpose of best master selection.

Step 3 

interface interface-id

Specify an interface to configure, and enter interface configuration mode.

Enter the number of the switch port, including port type (such as Fa for Fast Ethernet and Gi for Gigabit Ethernet), the base switch number (1), and the specific port number. For example: Fa1/1 is Fast Ethernet port 1 on the base switch.

Step 4 

ptp {announce {interval value | timeout value} | delay-req interval value | enable | sync {interval value| limit value}}

Specify the settings for the timing messages. These options are only available when the switch is in boundary mode.

•For announce interval, specify the time for sending announce messages. The range is 0 to 4 seconds. The default is 1 (2 seconds).

•For timeout value, specify the time for announcing timeout messages. The range is 2 to 10 seconds. The default is 3 (8 seconds).

•For delay request interval, specify the time recommended to the member devices to send delay request messages when the port is in the master state. The range is -1 second to 6 seconds. The default is 5 (32 seconds).

•For sync interval, enter the time for sending synchronization messages. The range is -1 second to 1 second. The default is 1 second.

•For sync limit, specify the maximum clock offset value before PTP attempts to resynchronize. The range is 50 to 500000000 nanoseconds. The default is 500000000 nanoseconds.

Step 5 

end

Return to privileged EXEC mode.

Step 6 

show running-config

Verify your entries.

Step 7 

copy running-config startup-config

(Optional) Save your entries in the configuration file.