Michael McNamara

technology, networking, virtualization and IP telephony

Network Time Protocol (NTP)

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1111976_16319994 [ad name=”ad-articlebodysq”]I’m sometimes amazed at how many large organizations don’t have a centralized Network Time Protocol (NTP) server setup and devices configured appropriately. When troubleshooting a problem it’s vital that the timestamps in the logs for each switch, router, server and appliance match up correctly.

I’m currently using two CentOS Linux servers to provide time services to over 10,000 devices in the network. My two servers are themselves syncing up with pool.ntp.org over the Internet. With CentOS I didn’t need to build the software, I only needed to install the NTP package through YUM and then configure it appropriately. It was really easy, much easier than it was say 10 years ago when you had to compile the NTP software (University of Delaware) by hand hoping you didn’t run into some missing library of version mismatch with the compiler.

We would first need to install the NTP software using YUM;
[root@hostname ]# yum install ntp

We would need to start the NTP daemons;
[root@hostname ]# service ntpd start

We would need to configure the server so the NTP software would start after every reboot;
[root@hostname ]# chkconfig ntpd on

With that step done we’d have ourselves and internal NTP server which would sync itself to the Internet (default configuration file in /etc/ntp.conf) and then our internal devices would sync to it.

Here are the CLI commands for configuring the ERS 8600 switch properly;

config bootconfig tz dst-name "EDT"
config bootconfig tz name "EST"
config bootconfig tz offset-from-utc 300
config bootconfig tz dst-end M11.1.0/0200
config bootconfig tz dst-start M3.2.0/0200

config ntp server create a.b.c.d
config ntp server create a.b.c.d
config ntp server create a.b.c.d
config ntp enable true

I’ve add the two configuration statements for the new Daylight Saving Time changes that were enacted in 2007. Please also note that I’m in the Eastern timezone (EDT/EST) so if you’re not in the Eastern timezone you would need to supplement your timezone abbreviation appropriately.

Here are the commands for an ES460,ES470,ERS4500 or ERS5500 series switch

5520-48T-PWR# config terminal
5520-48T-PWR (config)# sntp server primary a.b.c.d
5520-48T-PWR (config)# sntp server secondary a.b.c.d
5520-48T-PWR (config)# sntp enable
5520-48T-PWR (config)# exit5520-48T-PWR#

The ERS 4500/5500 Series now supports Daylight Saving Time. This feature is NOT supported on the ES460 and ES470 switches. –-CORRECTION: this feature is support on the ES460/470 as of v3.7.x software, please see update at the bottom of this post for additional information. If you wanted to configure the timezone on the ERS4500/ERS5500 switch you would use the following commands;

5520-48T-PWR>enable
5520-48T-PWR# config terminal
5520-48T-PWR (config)# clock time-zone EST -5
5520-48T-PWR (config)# clock summer-time EDT date 9 Mar 2008 2:00 2 Nov 2008 2:00 +60
5520-48T-PWR (config)# exit
5520-48T-PWR#

You can use “show sntp” and “show clock” the ERS 5500 Series switch to check out your changes;

5530-24TFD#show sntp
SNTP Status:                      Enabled
Primary server address:         10.1.20.1
Secondary server address:     10.1.20.1
Sync interval:                      24 hours
Last sync source:                 10.1.20.1
Primary server sync failures:    0
Secondary server sync failures: 0
Last sync time:                  2008-06-14 14:47:31 GMT-04:00
Next sync time:                  2008-06-15 14:47:31 GMT-04:00
Current time:                     2008-06-15 13:52:24 GMT-04:00

5530-24TFD#show clock
Current SNTP time  :    2008-06-15 13:52:29 GMT-04:00
Summer time is set to:
start: 28 March 2007 at 02:00
end: 30 August 2008 at 15:00
Offset: 60 minutes. Timezone will be 'EDT'Time Zone is set to 'EST', offset from UTC is -05:00

Hopefully this will provide a brief look into NTP,SNTP and you’ll agree that it really isn’t that hard to setup and configure properly.

Cheers!

Update: June 17, 2008

After posting the article above I decided I would confirm that the Daylight Saving Time feature was not available on the Nortel Ethernet Switch 460/470. I found that as of v3.7.x software the feature is supported on the switches. The configuration commands are identical to the ERS4500/ERS5500 switches. Here’s an example specifically for the Eastern timezone.

470-48T>enable470-48T#config term
Enter configuration commands, one per line.  End with CNTL/Z.
470-48T(config)#clock time-zone EST -5 00
470-48T(config)#clock summer-time EDT date 9 Mar 2008 02:00 2 Nov 2008 2:00 +60
470-48T(config)#show clock summer-time
Summer time is set to:start: 9 March 2008 at 02:00end: 2 November 2008 at 02:00
Offset: 60 minutes. Timezone will be 'EDT'
470-48T(config)#exit

Cheers!

You might also want to read these other posts...

  1. NVR Audit data initialized
  2. Changing SNMP Community Strings
  3. Expect Script – Daylight Saving Time

Comments

  1. I found your site on technorati and read a few of your other posts. Keep up the good work. I just added your RSS feed to my Google News Reader. Looking forward to reading more from you down the road!

  2. Hi, Nice article – Just wondering if you ever ran in to this: Whenever I set the time zone to PST: ‘clock time-zone PST -8 0’ and then update sntp the clock shows GMT time as below… Any thoughts? Cheers.

    sw(config)#show sntp
    SNTP Status: Enabled
    Last sync time: 2009-12-07 15:56:14 GMT-08:00
    Next sync time: 2009-12-07 17:56:14 GMT-08:00
    Current time: 2009-12-07 15:56:34 GMT-08:00

    sw#show clock
    Current SNTP time : 2009-12-08 00:00:08 GMT
    Summer time is set to:
    start: 14 March 2010 at 02:00
    end: 7 November 2010 at 02:00
    Offset: 60 minutes. Timezone will be ‘DST’
    Time Zone is set to ‘PST’, offset from UTC is -08:00

  3. I have an ERS 4548GT-PWR in my lab that is working fine. It has the following specs;
    Hardware Version: 03
    Firmware Version: 5.1.0.7
    Software Version: v5.1.2.004

    You might want to try and upgrade the software, it could be a bug.

    4548GT-PWR#show sntp
SNTP Status:                    Enabled
Primary server address:         10.1.2.1
Secondary server address:       10.1.2.1
Sync interval:                  24 hours
Last sync source:               10.1.2.1
Primary server sync failures:   1
Secondary server sync failures: 1
Last sync time:                 2009-12-08 15:11:40 GMT-05:00
Next sync time:                 2009-12-09 15:11:40 GMT-05:00
Current time:                   2009-12-08 22:50:23 GMT-05:00

4548GT-PWR#show clock
    Current SNTP time  :    2009-12-08 22:50:28 GMT-05:00
    Summer time is set to:
start: 9 March 2008 at 02:00
end: 2 November 2008 at 02:00
    Offset: 60 minutes. Time zone will be 'EDT'
    Time zone is set to 'EST', offset from UTC is -05:00

    Good Luck!

  4. Thanks, I thought that might be the case…

    I’m pretty new to Nortel coming from mainly a Cisco background, do you have a any pointers for finding config guides, cli guides, decent books etc. I find searching for information on Nortel’s site pretty painful. Any pointers would be greatly appreciated. Thanks.

  5. Hi Michael,

    I have configured NTP on Nortel ERS 8010 as per your suggestion and it works. Thanks much for your sharing. However, is there any way to keep local time and hardware time the same. Following is my output and I got the right local time while the hardware time show the UTC time since my NTP server just gives UTC.

    ERS8010# date
    local time: WED JUL 14 16:17:54 2010 WST
    hardware time: WED JUL 14 08:17:54 2010 UTC:

    And, this is my NTP config in ERS 8010 switch.
    config bootconfig tz name “WST”
    config bootconfig tz offset-from-utc -480
    config ntp server create A.B.C.D

    config ntp enable true
    config ntp interval 15

    Thanks in advance for your advice.

    Regds.

    • Hi Lay,

      The hardware time will always be in UCT format. It’s the local time that is used in the logs and all operations that will be reflective of the timezone that the equipment is located in.

      Cheers!

  7. If you have to enter a specific date for summertime, what happens the following year when the date is no longer on a Sunday? Do you have to enter new dates every year?

    • Hi Joe,

      Yes you do… similar to Cisco behavior although in 6.2.x software for the Avaya Ethernet Routing Switch 5000 series you no longer need to stipulate the year.

      Good Luck!

    • Or at least have it forward NTP client requests to a remote NTP server. That way I would only have to change the NTP server address in my core switches instead of changing the address in every device. Thank you very much!!

  10. Hi Michael,

    I am trying to set the British Day Light Saving on the 8600 and have worked out the below commands using ACLI:

    boot config tz name GMT
    boot config tz dst-offset 60
    boot config tz dst-start 03310200
    boot config tz dst-end 10270100

    We are running 7.2.1 on our 8600’s and using ACLI.

    Are the above commands correct?
    After you run these commands do you need to restart the switch? (It says in the documentation to restart the switch)
    Do I need to run these commands every year?

    Your assistance will be appreciated.

    Regards,
    Meraj

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