Cisco ASR 9000 Series

CHAPTER 11
Implementing NTP
Network Time Protocol (NTP) is a protocol designed to time-synchronize devices within a network.
Cisco IOS XR software implements NTPv4. NTPv4 retains backwards compatibility with the older versions
of NTP, including NTPv3 and NTPv2 but excluding NTPv1, which has been discontinued due to security
vulnerabilities.
This module describes the tasks you need to implement NTP on the Cisco IOS XR software.
For more information about NTP on the Cisco IOS XR software and complete descriptions of the NTP
commands listed in this module, see Related Documents, on page 230. To locate documentation for other
commands that might appear in the course of running a configuration task, search online in Cisco ASR 9000
Series Aggregation Services Router Commands Master List.
Table 25: Feature History for Implementing NTP on Cisco IOS XR Software
ModificationRelease
This feature was introduced.Release 3.7.2
Support was added for IPv6 addresses, VRFs, multicast-based associations, and burst
and iburst modes for poll-based associations.
Release 3.9.0
Support was added for NTP-PTP interworking.Release 4.3.0
Support was added for NTP server inside VRF interfaceRelease 4.3.1
This module contains the following topics:
•
Prerequisites for Implementing NTP on Cisco IOS XR Software, page 208
•
Information About Implementing NTP, page 208
•
How to Implement NTP, page 209
•
Configuration Examples for Implementing NTP, page 226
•
Configuring NTP server inside VRF interface, page 228
•
Additional References, page 230
Cisco ASR 9000 Series Aggregation Services Router System Management Configuration Guide, Release 5.1.x
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