I am trying to connect the new 6509E switch with 3750 using SFP module. 6509E is running 12.2(33)SXH and has a SUP720-3B and 3750 is running IOS 12.2(25)SEE2. We can't seem to establish the connectivity using port-channel or single port. Port is properly configured on both sides i.e. trunk encapsulation dot1q and switch mode trunk. What could be the problem? The switches are only 30 meters apart and we are running multimode 62.5/125 fiber between them. Is that too short and do we need to use the attenuator?