Cisco Nexus 5600 Series - Configuring NTP; Information about NTP; Information about the NTP Server

CHAPTER 18
Configuring NTP
This chapter contains the following sections:
•
Information About NTP, page 219
•
Licensing Requirements, page 221
•
Prerequisites for NTP, page 221
•
Guidelines and Limitations for NTP, page 221
•
Default Settings for NTP, page 222
•
Configuring NTP, page 222
•
Verifying the NTP Configuration, page 231
•
Configuration Examples for NTP, page 232
Information About NTP
Information About the NTP Server
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).
•
A stratum 2 NTP server receives its time through NTP from a stratum 1 time server.
Cisco Nexus 5600 Series NX-OS System Management Configuration Guide, Release 7.x
OL-31641-01 219