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Cisco 3850 Stacks

Zachary Ballard
Level 1
Level 1

So I am stacking two separate 3850 Stacks together. They are in separate buildings. I am using sfp ports, both stacks have NM4-1G modules. I am configuring one link between the two and cannot get any data to pass between the two.

The links show up/up, the Lights on both ends are green, If i shutdown one side, the other side goes down aswell. However, the switches are not discovering eachother via cdp and it is enabled. This is really odd. Both ends have a simple "switchport mode trunk" command configured. Any ideas?? 

Thanks!

3 Replies 3

Reza Sharifi
Hall of Fame
Hall of Fame

Can you post "sh run" from both switches and point out the interface number connecting them together? 

If you are using the 1Gig fiber port, it should be gi1/1/x

HTH

I recently switched jobs so I haven't been logged on here in a bit. I wanted to update this thread with the solution to my problem.

 

To recap, I was having an issue with trunking two switch stacks together. This simple task had me beat for two days. No matter the configuration, the two switches would not form a trunk. On the second day I finally decided to check the mac address table to see what mac address the switch was listing for the trunked port. This is when I found that the switch was not listing any mac addresses. This issue was caused by a Bug and after updating the code on these switches they worked perfectly. I am writing this from memory so I do not remember the specific bug #.

thanks for updating the fix if you have the software version you seen this on please add it to the thread , it will help someone
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