Reference Guide

System Time and Date | 1001
Figure 56-1. NTP Fields
Implementation Information
• On E-Series TeraScale, C-Series and S-Series, the switch can act only as a client to an NTP clock host.
• On the E-Series ExaScale, the switch can act as a client to an NTP clock host or as a server to other
downstream clients.
• FTOS supports Virtual IP addresses as NTP servers. However, in a network where the VRRP Master
router election takes place frequently over a period of time, the NTP association is bounced between
different physical routers and those routers may have different time settings for NTP. There is no
guarantee that the VRRP Master router and the VRRP Backup router will be synchronized for NTP
purposes and the NTP clients may not receive accurate clock updates.
Configuring Network Time Protocol
Configuring NTP is a one-step process:
1. Enable NTP.
Related Configuration Tasks
• Configure NTP broadcasts
• Set the Hardware Clock with the Time Derived from NTP
• Set the Hardware Clock with the Time Derived from NTP
• Disable NTP on an interface
• Configure a source IP address for NTP packets (optional)
Source Port
(123)
Destination Port
(123)
Length
NTP Packet Payload
Checksum
Leap
Indicator
Status
Type
Est. Error
Est. Drift Rate
Reference
Clock ID
Recieve
Timestamp
Transmit
Timestamp
Reference
Timestamp
Originate
Timestamp
Code: 00: No Warning
01: +1 second
10: -1 second
11: reserved
Precision
Range: 0-4
Code: 0: clock operating correctly
1: carrier loss
2: synch loss
3: format error
4: interface/link failure
Range: 0-4
Code: 0: unspecified
1: primary reference clock
2: secondary reference clock via NTP
3: secondary reference via some other host/protocol
4: eyeball-and-wristwatch
Range: +32 to -32