Extremes 2 Switches can't see each other

[elvin1993]

I can't connect 2 switches via optical port,
The primary switch is ExtremeSwitching 5520-24X - SFP Module 10051H.
Second switch: 210-Series 48 port - 16570 - SFP Module 10051H.

On the primary switch side, the LED is lit and the LED is not lit on the second switch.

Both sides are in Vlan 100 Trank and I additionally wrote no shutdown command,

but the indicator on the second switch is not lit. and CDP naiber detailes on the core SWitch side also do not see the switch

Please assist me with this issue, what i need to do for fix this.

[Kar_Del_Moral]

Morning, second the auto-neg configuration, just got that issue myself, when using 1gb SFP in the 10GE ports, just disable the auto-neg and manually configure the rest of the parameters.

[EXTR_Paul · Accepted solution]

when using 1Ge optics in 10GE ports you can sometimes run into negotiation issues.

On both switches disable auto-neg on the port.