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Configure Your Devices Network Time With This Guide

by Darin Knobbe, on Dec 18, 2020 1:00:00 PM

Time management is most important when seeking to achieve maximum efficiency. Whether it is your day-to-day time management or your time management during a project, it all relates back to how effective you can be with your time. Today, we look at time a little bit different. We will be diving into the Network Time Protocol and configurations to synchronize your network devices. Think of it as helping your devices achieve the most effective time management. To help with configurations, we will use Cisco's Nexus 7000 series. Feel free to skip to the configurations by clicking here.

Nexus 7000 Overview

This Cisco Nexus series was built for mission-critical environments at the enterprise and service provider levels. As networks focus towards zero downtime goals, the Nexus 7000 series can be found at the core of your network bringing virtualization, efficiency, scalability, high density, and overall performance. As your data center grows, look towards the Nexus 7000 series to compete for a spot on your rack.

Cisco Nexus 7000 Series

NTP & Nexus

Network Time Protocol (NTP) is a protocol used to synchronize computer clock times in a network. It belongs to and is one of the oldest parts of the TCP/IP protocol suite. The term NTP applies to both the protocol and the client-server programs that run on computers. NTP synchronizes the time of day among other time servers and clients with the goal that you can relate any troubleshooting or errors from different system devices.  

A Few Things to Remember from Cisco

  • NTP server begins in the Cisco NX-OS Release 5.2. 
  • Peer association with another device is necessary when you are certain that your clock is reliable
  • A peer configured alone takes on the role of a server and should be used as a backup.  If you have 2 servers or for more information, get in touch with a PivIT Representative.
  • Up to 64 NTP entities can be configured. 
  • If CFS is disabled for NTP at that point, NTP doesn't disperse any configuration and doesn't acknowledge an appropriation from different devices in the system. 
  • After CFS is enabled for NTP the section of an NTP configuration command bolts the network for NTP configuration until a submit order is entered. During the lock, no progressions can be made to the NTP set up by some other device in the network aside from the device that started the lock. 
  • If CFS is used to disperse NTP all devices in the network ought to have the equivalent VRFs configured as we use for NTP. 
  • If NTP is used in a VRF guarantee that the NTP server and peers can arrive at one another through the configured VRFs. 
  • NTP authentication keys should be physically conveyed on the NTP server and Cisco NX-OS devices over the system.

Configuring NTP on Nexus 7000

The Network Time Protocol (NTP) synchronizes the time of day across your time servers and clients with the goal that you can relate occasions when you get system logs and other time-explicit events from different system devices. NTP utilizes the User Datagram Protocol (UDP) as its transport protocol. All NTP interchanges utilize Coordinated Universal Time (UTC). 

NTP also utilizes a stratum to portray the separation between a network device and a definitive time source: 

  • A stratum 1-time server is appended to a definitive time source (for example, a radio or nuclear clock or a GPS time source). 
  • A stratum 2 NTP server gets its time through NTP from a stratum 1-time server.

Starting with Cisco NX-OS Release 5.2 the Cisco NX-OS device can utilize NTP to convey time. Different devices can configure it as a time server. We can likewise arrange the device to go about as a definitive NTP server to circulate time in any event, when it isn't synchronized to an outside time source.

Clocks are assets that should be shared across various procedures and across various VDCs. Multiple time synchronization protocols, for example, NTP and Precision Time Protocol (PTP) may be running in the framework and various occasions of a similar convention may be running in various VDCs.

NTP requires no license, any feature not included in a license package is gathered with the Cisco NX-OS system images and is provided with charges. NTP has the accompanying essentials: 

  • To arrange NTP we should have availability to in any event one server that is running NTP. 
  • To configure VDCs we should introduce the Advanced Services license.

NTP Enablement

configuration command ntp enablement from pivit globalconfiguration command no feature ntp from pivit global

Configuration Examples

We will walk through 11 configurations for NTP on the 7000 series Cisco Nexus switch. To quickly find one, just click below the configuration you'd like to find.

  1. Device as an Authoritative NTP Server
  2. NTP Server and Peer
  3. NTP Authentication
  4. NTP Access Restrictions
  5. NTP Source Interface
  6. NTP on Secondary VDC
  7. NTP Logging
  8. Enabling CFS Distribution for NTP
  9. Committing NTP Configuration Changes
  10. Discarding NTP Configuration Changes
  11. Verification

Device as an Authoritative NTP Server

We can configure the device to go about as an NTP server to convey time in any event when it isn't synchronized to a current time server.

authoritative ntp server configuration command from pivit global

NTP Server and Peer

An NX-OS device can be configured as an NTP server, also a peer. An NTP peer relationship enables network engineers to designate another host to consider synchronizing the time with in case a failure event occurs on the NTP server.

show ntp peers configuration command from pivit global

NTP Authentication

We can configure the device to authenticate the time sources to which the local clock is synchronized using the following steps:

ntp authentication configuration command from pivit global

In this example we can see how to configure the device to synchronize only to time sources that provide authentication key 42 in their NTP packets:

configuration command to show ntp authentication from pivit global

NTP Access Restrictions

ntp access restrictions configuration command from pivit global

NTP Source Interface

configuration command to ntp source interface from pivit global

NTP on Secondary VDC

ntp secondary vdc configuration command from pivit global

NTP Logging

ntp logging configuration command from pivit global

configuration command for ntp logging from pivit global

Enabling CFS Distribution for NTP

NX-OS also has a built-in proprietary feature known as Cisco Fabric Services (CFS) that can be used to distribute data and configuration changes to all Nexus devices. CFS distributes all local NTP configuration across all the Nexus devices in the network. It applies a network-wide lock for NTP when the NTP configuration is started. When the configuration changes are made, users can discard or commit the changes, and the committed configuration replicates across all Nexus devices.

Committing NTP Configuration Changes

configuration command for ntp configuration from pivit global

Discarding NTP Configuration Changes

discading ntp changes configuration command from pivit global

Verification

verfication configuration command for ntp from pivit global

PivIT Global

Here at PivIT, we offer a fresh approach to sourcing, maintaining, and servicing your data center infrastructure. We’ve reimagined the status-quo and offer our customers strategies not found in the traditional IT channels. Our focus is to examine your CAPEX/OPEX limitations and present you with options to free up your budget, achieve your goals and Do IT Better.

Topics:Cisco NexusNetwork ProtocolsNetwork Time Protocol

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