Ethernet Align Errors
This event is triggered when the number of alignment errors per second is higher than the value configured in the Expert Thresholds setup.
Ethernet Alignment errors are detected when a packet is not "aligned" on a phase boundary. For timing purposes, the network adapter card assembles and sends a "preamble" for Ethernet packets. Then timers on both Ethernet adapters (sending and receiving) synchronize (agree) on phase timing, and calculate a phase position to begin the actual packet. This phase position is used so that the receiving adapter can know when the packet begins, and how the packet should correspond to the actual signal wave.
Alignment errors can be caused by a number of factors. Typically, they are caused by a previous collision. When a collision occurs, either a CRC error or an Alignment error almost always results. In the case of an Alignment error, if the collision occurs during a transmission after the preamble, the position of the resulting signal with respect to the phase of the wave is incorrect. The receiving adapter acknowledges this, and the packet is discarded.
Possible reasons for the event:
bad cabling between station and hub/switch, a cable that is too long or electrical interference on the cable
a bad Ethernet card or router connection NIC