NTP (Network Time Protocol)


Scenario:

You are the owner of a Swiss watch factory. Time is everything to you and the same applies to your network. You want to make sure that your complete network is synchronized and up-to-date. Now get going since time is money!

Goal:

  • All IP addresses have been preconfigured for you.
  • EIGRP has been configured for full connectivity.
  • Configure router Planck and Atomic to be NTP Masters, use stratum 10.
  • Make sure router Planck and Atomic synchronize with each other.
  • Router Julian has to check router Planck and Atomic for NTP updates, it has to prefer router Atomic.
  • Configure router Julian so it broadcasts NTP packets on its FastEthernet 1/0 interface.
  • Configure router Century so it configures itself using the NTP broadcast packets from router Julian.
  • Configure router Planck to send NTP packets to multicast address 239.5.5.5.
  • Configure router Millenium to configure itself using the NTP multicast packets.

IOS:

c3640-jk9s-mz.124-16.bin

Topology:

Network Time Protocol NTP

Video Solution:

Configuration Files

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Once you are logged in you will find the configuration files right here.

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Written by René Molenaar - CCIE #41726

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About the Author: Rene Molenaar

René - CCIE #41726 is the creator of GNS3Vault.com where he shares CCNA, CCNP and CCIE R&S labs. He also blogs about networking on http://networklessons.com

6 Comments

    1. Great! good to hear it’s useful.

      Cisco has a couple of design guides about NTP on their website. They explain how you should setup NTP on a campus LAN and more…useful stuff if you need to design a network.

  1. I realized that you configured PIM in the multicast section, but I believe that is redundant, because there is no "multicast routing" involved, since we only require a TTL of 1. In this case, such as OSPF or EIGRP, we don’t need to enable PIM to listen to multicast messages.

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