3750 config register 0XF

Answered Question
Aug 24th, 2009

Hi

what the purpose of having the register set to 0xf in the 3750 ?

i have a situation where it its booting in bootstrap, and i think this is causing it each time.

anyone know the reason behind that, and if i shoulod set it to 0x2 ?

thanks

I have this problem too.
2 votes
Correct Answer by Joe Clarke about 7 years 3 months ago

This looks fine. I see no reason why the switch wouldn't boot directly to the 12.2(35)SE image on flash. As was statement previously, it would help to see the console output from the switch booting up.

Correct Answer by Peter Paluch about 7 years 3 months ago

Hello Jafar,

As Joe has pointed out very correctly, the value 0xF is a correct configuration register value for a switch. In fact, I haven't seen a 29x0 or 3xx0 switch having a different configuration register value and I even have a feeling that the entire configuration register is there just for compatility with the common IOS code base and it is ignored completely.

Please, if possible, post here the transcript of the booting progress of that switch. We might be able to help you better.

Best regards,

Peter

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Overall Rating: 5 (2 ratings)
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Joe Clarke Mon, 08/24/2009 - 11:12

No, 0xF is the proper value for this device. What is the output of "show boot" from this switch?

Correct Answer
Peter Paluch Mon, 08/24/2009 - 11:28

Hello Jafar,

As Joe has pointed out very correctly, the value 0xF is a correct configuration register value for a switch. In fact, I haven't seen a 29x0 or 3xx0 switch having a different configuration register value and I even have a feeling that the entire configuration register is there just for compatility with the common IOS code base and it is ignored completely.

Please, if possible, post here the transcript of the booting progress of that switch. We might be able to help you better.

Best regards,

Peter

jafar.tarawneh@... Mon, 08/24/2009 - 15:25

thanks,

as350057s02#sh boot

BOOT path-list : flash:c3750-ipservices-mz.122-35.SE5/c3750-ipservices-mz.122-35.SE5.bin

Config file : flash:/config.text

Private Config file : flash:/private-config.text

Enable Break : no

Manual Boot : no

HELPER path-list :

Auto upgrade : yes

Auto upgrade path :

as350057s02#

jafar.tarawneh@... Mon, 08/24/2009 - 15:38

i have the wrong stement there,

this is my issue,

still would like to know the reason behind 0xf, compared to other cisco devices.

thanks

Joe Clarke Mon, 08/24/2009 - 15:49

The config register on the 3750 (and other desktop switches) is fixed at 0xF. It cannot be changed, but it is analogous to 0x2102 on other platforms in that it causes the switch to boot from flash, and load the saved config.text.

Correct Answer
Joe Clarke Mon, 08/24/2009 - 15:47

This looks fine. I see no reason why the switch wouldn't boot directly to the 12.2(35)SE image on flash. As was statement previously, it would help to see the console output from the switch booting up.

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