Cabletron Systems TRMMIM manual Non-Isolating Errors

	Ring Map
AC Errors	The count of frames containing errors in the ARI
	(Address Recognized Indicator) or FCI (Frame Copied
	Indicator) bits. Also known as ARI/FCI errors, AC errors
	occur during the Ring Poll or Neighbor Notification
	process when one station fails to correctly set the ARI
	(address recognized) and FCI (frame copied) indicator
	bits on the current AMP (active monitor present) or SMP
	(standby monitor present) frame intended for it, thus
	leaving its downstream neighbor without an accurate
	upstream neighbor’s address. AC errors are detected
	when a station receives more than one AMP frame with
	ARI and FCI bits still set to 0 without seeing an
	intervening SMP frame with its bits set to 1, or when the
	station detects an SMP frame with its ARI and FCI bits
	set to 0 without having seen an AMP frame with its ARI
	and FCI bits set to 1. When a station detects an AC error,
	it stops the Ring Poll process by not issuing its own SMP
	frame; no other ring recovery procedures are initiated.
	These errors are typically associated with hardware
	(adapter) problems.
Abort Seq	The number of times that the associated station has
	issued an abort sequence during transmission. These
	occur when a station begins to queue data onto a token,
	and subsequently detects that the token is corrupted
	(because it does not have an ending delimiter after its
	access control field). The station reports the error, but
	does not release the corrupt token back onto the network.
	This will cause the Active Monitor to purge the ring and
	issue a new token. A failing network adapter is likely to
	be the cause of this isolating error.
Internal Error	The count of errors caused by the station recognizing a
	recoverable internal error in its adapter and removing
	itself from the ring. Possible problems with the adapter
	hardware include inoperable chip set, timer, or counters.
Non-Isolating Errors
Lost Frame Errors	The number of frames that the associated station has
	transmitted that have not completely returned before its
	Timer Return to Repeat (TRR) timer has expired (after 4.1
	milliseconds). These non-isolating errors are generally
	harmless, since they are often caused by a brief
	disruption of ring clocking as a station enters or exits the
	ring. However, they do require the Active Monitor to
	purge the ring.
Congestion Errors	The number of times the associated station was unable to
	copy frames addressed to it because of a lack of internal
	buffering – that is, the station is receiving frames faster
	than its adapter can copy information from the receive

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