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Cold startup time for Catalyst switches


My customer uses WS-C3560G-48TS-E switches in air traffic control systems. A requirement for one project is that the entire system be up and running in under five minutes. The WS-C3560G-48TS-E and its replacement - WS-C3560X-48T-E with C3KX-NM-1G - take about four minutes to start up. With other devices added in they exceed their required startup time.

They also use WS-C3560V2-48TS-E switches which take about two minutes to start up but they want they GE.


1) Is there way to improve the start up time in the WS-C3560G-48TS-E and WS-C3560X-48T-E switches?

2) Is there another Catalyst switch with similar specifications to WS-C3560G-48TS-E and WS-C3560X-48T-E that has a quicker start up time.




Also, is there a list of boot times for Cisco Catalyst switches? Where is this statistic available?



Hello David,

I have always experienced a difference in startup times, it just depends on the image and the hardware. I haven't seen anywhere where Cisco have mentioned or documented the startup times. It does vary - everything has to go through the boot process anyway. I don't think we have any control over this.

Especially with these type of stackable switches.

You cannot do much about making the booting process faster for a switch. It has to load the IOS, run the hardware test and then load the IOS and config on the DRAM. New 3560/3750 stackable switches run the stack election process that's why they usually take a while.

I know its not much help to the questions raised, but I hope it helps in some form.

Perhaps someone has had experience of making boot times faster. I wouldn't know how, but would be great to know of a way!

Please rate useful posts and remember to mark any solved questions as answered. Thank you.

Please rate useful posts & remember to mark any solved questions as answered. Thank you.
Leo Laohoo
VIP Community Legend

Have you read about Warm Reload?

Besides, if it's a critical network, I'd go for a stacked switch and dual home everything.

Switches that support stacking (other than VSS) are 2960S and 3750X.

Unfortunately, reloading of VSS goes beyond 5 minutes so this is out of the question.

Another thing, I don't know what metrics you use to measure the bootup time of an appliance but what we do is measure the time the switch powers up to the time you can start pinging the switch.

Warm reload sounds interesting. Will this work for switches? The documentation you linked to refers to routers.

Can't do the stacked switching. The end user wants sort of a Le Mans start. All power down, need to get all systems back up and running in under five minutes.

If warm reload works for switches, will bootup time be reduced? Will warm reload work if the switch has completely cost power?



Leo Laohoo
VIP Community Legend

Warm reload, if done correctly will cut the bootup by half because the switch will bypass the bootstrap.  It will reload straight to the IOS.

Because it's called "reload", then it won't work if the appliance has lost power.

Have you tested the bootup time of a 2960S? 

I think that Enterprise software is required. But is there a way to find the reboot interval short of buying one and turning it on?

Jeff Van Houten

AIR TRAFFIC CONTROL??? I hope you're looking at something a little more robust than a 2960/3560.

Sent from Cisco Technical Support Android App

In what way is a 3560 not robust? But I'm open to suggestions as long it has the same capabilities as the 3560 and has a faster reboot time.

Leo Laohoo
VIP Community Legend

The main difference with the 3560X as compared to 2960S or 3750X or 3850 is the fact that there's no "redundancy", per se.

Unlike the 2960S, 3750X or 3850, the 3560X can't be stacked to form a single logical switch.  In a high availability (like an air traffic control), I'd have each computer dual homed to a stack.  If one switch fails, the computer chugs along nice because of the second NIC.

Sure, the "X"-series switch can have dual power supply but this alone does not guarantee if your switch fails.  Stack switching, however, bridges that gap.

NOTE:  I should make it a point to stop talking about 3750X and 3850 and instead talk about the 3850 as the 3750X is about to become irrelevant.


Dual home the client PC to a pair of 4500 or 6500 running VSS doing your best to avoid relying in any single piece of hardware and avoid the whole reboot process completely.

Sent from Cisco Technical Support Android App

-- CCNP, CCIP, CCDP, CCNA: Security/Wireless Blog:

Dual home the client PC to a pair of 4500 or 6500 running VSS doing your best to avoid relying in any single piece of hardware and avoid the whole reboot process completely.

Unfortunately, a single 4500 or a 6500 bootup time goes more than 5 minutes.  Gets even worst when you configure VSS.

Joseph W. Doherty
Hall of Fame Expert


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As others have already posted, it's likely difficult to have much control over cold boot times.

Perhaps the requirement should be how to avoid the need for fast cold boot times.  I.e. a design that mitigates the need to wait on a cold boot.


Can you let me know which airport you work at and I will avoid it in future?

I don't want my plane falling out of the sky while you wait for the ASIC checks to complete.

Philip D'Ath

Although an older post, I read over this with some shock.

You should be using something with dual supervisors, like a 4507, or something that supports VSS.

I would personally use a 4507.  Then you can use features like ISSU and do no-disruption upgrades.  Everything is also hot plug.  You should never need to shutdown or remove power from the 4507.