Cisco Nexus 3548 - Configuring NTP; Information about NTP

CHAPTER 8
Configuring NTP
This chapter contains the following sections:
•
Information About NTP, page 53
•
NTP as a Time Server, page 54
•
Distributing NTP Using CFS, page 54
•
Clock Manager, page 54
•
Virtualization Support, page 54
•
Licensing Requirements for NTP, page 54
•
Guidelines and Limitations for NTP, page 55
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Default Settings, page 55
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Configuring NTP, page 56
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Related Documents for NTP, page 65
•
Feature History for NTP, page 65
Information About NTP
The Network Time Protocol (NTP) synchronizes the time of day among a set of distributed time servers and
clients so that you can correlate events when you receive system logs and other time-specific events from
multiple network devices. NTP uses the User Datagram Protocol (UDP) as its transport protocol. All NTP
communications use Coordinated Universal Time (UTC).
An NTP server usually receives its time from an authoritative time source, such as a radio clock or an atomic
clock attached to a time server, and then distributes this time across the network. NTP is extremely efficient;
no more than one packet per minute is necessary to synchronize two machines to within a millisecond of each
other.
NTP uses a stratum to describe the distance between a network device and an authoritative time source:
•
A stratum 1 time server is directly attached to an authoritative time source (such as a radio or atomic
clock or a GPS time source).
Cisco Nexus 3548 Switch NX-OS System Management Configuration Guide, Release 6.x
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