10G SFP+ to 1G SFP No Link?

[JB-TX]

Hello,

I have two switches 3850 with 10G expansion module and a 3750 with 1GIG SFP.

3850 has a SFP+ 10G fiber connector and the 3750 has the 1G SFP fiber connection. There is no link.

Adding a 1G to the 3850 and keeping the 1G to the 3750 will allow a link.

My question: Is it possible to make the 10G fiber SFP+ Module link to the 1GIG? Or does the 10G not downgrade this way? Any CLI command to make this work?

[Reza Sharifi]

Hi,

Unfortunately this will not work as the 3850 is 10Gig only and not 1/10 and the 3750 is only 1Gig. Also, the 3750 does not support 10Gig module. So, you would have to go with a 1Gig module on the 3850 to make a Gig connection with the 3750.

HTH 

[Joseph W. Doherty]

"Also, the 3750 does not support 10Gig module."

BTW, correct, but there was one 3750 model that had a built-in 10G interface.

[acampbell]

Hi,
You have not mentioned what type og 10G expansion module you are using.
Use the document below to see what interface numbers you need to configure:-

https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3850/hardware/installation/guide/b_c3850_hig/b_c3850_hig_chapter_011.html

[JB-TX]

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@acampbell wrote:

Hi,
You have not mentioned what type og 10G expansion module you are using.
Use the document below to see what interface numbers you need to configure:-

https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3850/hardware/installation/guide/b_c3850_hig/b_c3850_hig_chapter_011.html

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C3850-NM-8-10G