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Unable to connect two switch using two fibre optic cable without one port forcing to 'disable'.

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bazil2

Technical User
Feb 15, 2010
148
DE
(Elementary user)

Can anyone please explain the following ....

I have connected this switch (Port 50 and Port 51):


To this switch (Ports 25 and Port 26):

I am connecting using fibre optic and have 'crossed' the cables over accordingly.

What I don't understand is that Port 26 is showing as disabled. If I unplug Port 25, then it turns green and becomes enabled; plugging in Port 25 again forces Port 26 to be disabled again.

Does anyone know what I am doing wrong?

Best regards
 
Spanning tree is probably blocking it.

Did you intend to create a channel-group and put both links in it so that both links come up simultaneously?
 
Many thnaks for your help!

Well basically the idea was to simply connect the two switches and make use of the most bandwidth possible.

Last night I experimented with the Smartports settings and I designated these ports as 'Cisco switches'; this resulted in the disabled port becoming active.

Does this sound logical?

I looked up the spanning tree concept and see what you mean as to how it may be blocking.

Best regards
 
I agree, definitely a spanning tree issue. Create a port channel to resolve your issue.

Jim Rapier
"Money can't buy happiness, but it can buy a big ass boat and you can sail right up to it." - Johnny Depp
 
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