Hitachi US7070447-001 Ethernet Tips, Alignment errors, Oversized frames, FCS errors, Dribble bits

Draft Level—Hitachi Confidential

	Troubleshooting at the MAC Layer
alignment errors	Frame that contains a total number of bits not divisible by
	eight and fails the checksum test. This failure may be a
	result of collision, a defective NIC, bad cabling, etc.
oversized frames	Frame greater than the maximum Ethernet frame size of
	1518 bytes. This failure may be caused by jabbering or
	defective devices in the network. Can cause FIFO buffer
	overflow, collisions, fragments, CRC, or alignment errors.
FCS errors	Generated when the CRC value on both the sending/
	receiving stations are not identical. This value is
	calculated to verify the data integrity of the packet. If the
	receiving station recalculates the CRC and the value is
	not the same, the packet is discarded.
dribble bits	As a result of a transmitter (MAC) with poor timing.

Ethernet Tips

❒Ensure that both port speed and duplexity on the switch and endstations are the same.

❒By default, autonegotiation is enabled on the switch. If the endstation’s network adapter card is not autonegotiating properly, disable autonegotiation on the switch and manually configure the port settings using the following command:.

/ETHERNET/CONFIG >port

Doc Part Number, Version Number 9-3