Chapter 7 Administering the Switch

Managing the System Time and Date

The switch can send or receive NTP broadcast packets on an interface-by-interface basis if there is an NTP broadcast server, such as a router, broadcasting time information on the network. The switch can send NTP broadcast packets to a peer so that the peer can synchronize to it. The switch can also receive NTP broadcast packets to synchronize its own clock. This section provides procedures for both sending and receiving NTP broadcast packets.

Beginning in privileged EXEC mode, follow these steps to configure the switch to send NTP broadcast packets to peers so that they can synchronize their clock to the switch:

 

Command

Purpose

Step 1

 

 

configure terminal

Enter global configuration mode.

Step 2

 

 

interface interface-id

Specify the interface to send NTP broadcast packets, and enter

 

 

interface configuration mode.

Step 3

 

 

ntp broadcast [version number] [key keyid]

Enable the interface to send NTP broadcast packets to a peer.

 

[destination-address]

By default, this feature is disabled on all interfaces.

 

 

 

 

(Optional) For number, specify the NTP version number. The

 

 

range is 1 to 3. If you do not specify a version, Version 3 is used.

 

 

(Optional) For keyid, specify the authentication key to use when

 

 

sending packets to the peer.

 

 

(Optional) For destination-address, specify the IP address of the

 

 

peer that is synchronizing its clock to this switch.

Step 4

 

 

end

Return to privileged EXEC mode.

Step 5

 

 

show running-config

Verify your entries.

Step 6

 

 

copy running-config startup-config

(Optional) Save your entries in the configuration file.

Step 7

 

 

 

Configure the connected peers to receive NTP broadcast packets as

 

 

described in the next procedure.

 

 

 

To disable the interface from sending NTP broadcast packets, use the no ntp broadcast interface configuration command.

This example shows how to configure a port to send NTP Version 2 packets:

Switch(config)# interface gigabitethernet1/0/1

Switch(config-if)#ntp broadcast version 2

Beginning in privileged EXEC mode, follow these steps to configure the switch to receive NTP broadcast packets from connected peers:

 

Command

Purpose

Step 1

 

 

configure terminal

Enter global configuration mode.

Step 2

 

 

interface interface-id

Specify the interface to receive NTP broadcast packets, and enter interface

 

 

configuration mode.

Step 3

 

 

ntp broadcast client

Enable the interface to receive NTP broadcast packets.

 

 

By default, no interfaces receive NTP broadcast packets.

Step 4

 

 

exit

Return to global configuration mode.

 

 

 

Catalyst 3750-E and 3560-E Switch Software Configuration Guide

 

OL-9775-02

7-7

 

 

 

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Cisco Systems 3750E manual Interface interface-id, Ntp broadcast version number key keyid, Destination-address