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RE: RUNT Packets


Shimon and Pat are correct.  And if anyone should know, it is Shimon and
Pat.  Please be careful to not confuse what is standardized and what is
implemented.  Counting discarded short packets is not standardized, but by
de facto, most MACs implemented do count them.


	-----Original Message-----
	From:	Louis Lin [mailto:louislin@xxxxxxxx]
	Sent:	Thursday, November 16, 2000 4:20 PM
	Cc:	stds-802-3-hssg@xxxxxxxx
	Subject:	Re: RUNT Packets


	I have to disagree with your statement of "The MAC silently discards
	that are shorter than the minimum". When MAC is receiving a packet
	forwarding the packet data to the host. If the the EOP comes before
	MAC needs to inform host to discard the packet and that packet
needed to be
	counted in RMON. Otherwise we will see packets disappear(packet
	mis-match) if they are shortened by what ever reasons.

	Standard doesn't need to say anything about it, but saying "The MAC
	discards packets that are shorter than the minimum"  is not good.
And I
	believe most MACs in the market count undersized packets.

	Of course, most undersized packets don't come with good CRC. But we
	make this kind of assumption.



	Shimon Muller wrote:

	> > The important point is that runts are not counted by MACs.
	> > The MAC silently discards packets that are shorter than the
	> > It has no counter for them.
	> Pat is absolutely correct.
	> > Unless someone is proposing creating a new runt MIB object,
runts do not
	> > apply to 10 Gig Ethernet because we do not have repeaters.
	> I do not believe we should create such an object.
	> Just ignore the "shortened" frame. This is not something that is
	> to happen very often. And if it does, there are going to be other
	> that will give you plenty of indication that something is broken.
	>                                                 Shimon.