All Gigabit capable copper taps negotiate, establish and maintain two separate links between the tap and the endpoint devices of the link.  If one link endpoint device is only 10/100 capable and the other endpoint is 10/100/1000 capable then the taps respective tap assembly ports will each negotiate to the highest available speed – resulting in a speed mismatch and significant performance issues on the link. The required solution is to hard set the ports of both the endpoint devices and the tap assembly to fixed speed and duplex settings.
Network monitoring switches are not in line products, and receive their traffic from external taps or mirror ports. If simple non-aggregating passive fiber taps are used as the source of data to provide inputs to a network monitoring switch then the ports on that device must have Auto-negotiation disabled in order to accept data. But if other ports on that same device are used to accept data from SPAN ports or aggregation taps it is customary for Auto-negotiation to be used.
Datacom Systems SINGLEstream and VERSAstream products include the flexibility to change speed/duplex and Auto-negotiation settings independently on any and all ports – providing maximum flexibility.