About Daylight Saving Time

[SENOL YILDIRIM]

Hello from Turkey;

This year my country will not do DST (Daylight Saving Time) arrangement  , so we should do any change settings on switch and routers? or any advice?.

Şenol.

Thanks/Best Regards

[Joseph W. Doherty]

Consider using UCT then DST is non-issue.

[Richard Burts · Accepted solution]

While I find that usually he gives very good advice, in this case I do not agree with my colleague Joseph. In most switch and router IOS there are two commands that deal with how to represent time. There is clock timezone and clock summer-time. Using clock timezone to specify UCT will instruct the switch or router to not process the offset for local time. But it does not deal with Daylight Savings. To control daylight savings you would specify clock summer-time - or in your case no clock summer-time to remove the processing for Daylight Savings time.

HTH

Rick

[SENOL YILDIRIM]

Thank you very much for your answer.

[Joseph W. Doherty]

Using clock timezone to specify UCT will instruct the switch or router to not process the offset for local time. But it does not deal with Daylight Savings.

Exactly, "... it does not deal with Daylight Savings."!

Which is why I suggested considering it, as it avoids the maintenance issues involved with keeping DST accurate when dates for it are changed by government.  Fortunately, that happens rarely, but it did in the US several years ago.  The OP notes "This year my country will not do DST (Daylight Saving Time) arrangement."  So, another example of DST being changed by government.

Although it may not pertain to a country the size of Turkey, using UCT also makes it easier to compare times when something happens between equipment in different time zones.  In my former position, I worked within an international company, and having a single time setting (UCT) on all our network equipment made it easier to compare log entries from a router in Japan to one in France.

In my current position, I work in a company whose footprint (currently) is across the US.  Again, using UCT makes it easier to compare timestamps across US time zones.  Also, specific to the US, there are parts of the US, where we have equipment in locales that don't use DST, so some of our equipment in the same time zone would differ by an hour during DST.

So, again, I suggest considering using UCT instead of dealing with local time and DST.

Rick did correctly explain how to configure removing support for DST and so you can adjust your equipment not to do DST.  Maybe in a year or two, your government will use DST again, and then you can adjust the settings again.  ;)

[Richard Burts]

Joseph

I see your point about having a single time zone if the organization is large enough to span multiple time zones. And UCT is a good candidate for this. And I see your point that if we truly use UCT that it does not adjust for Daylight Savings. But the question then becomes how do we get the routers and switches to truly use UCT. Specifying UCT as the time zone is not sufficient. We need to be careful to remove the clock summertime command from the config.

HTH

Rick

[Joseph W. Doherty]

But the question then becomes how do we get the routers and switches to truly use UCT. Specifying UCT as the time zone is not sufficient. We need to be careful to remove the clock summertime command from the config.

Rick, agreed.  I wasn't describing how, just suggesting considering switching to a different time base usage, per OP's "or any advice?"; avoiding DST issues in the future.

I see your point about having a single time zone if the organization is large enough to span multiple time zones.

Although certainly it's more convenient for such, but using UCT doesn't have to be restricted to such.  Again, it's to avoid future DST issues (as what triggered the OP) and it better positions you, I believe, for long term.

However, to OP, do understand there's nothing really "wrong" using local time either.