RE: aRunts
Hi Geoff,
I think you are confusing runts and short events. When operating in CSMA/CD,
runts are normally collision fragments. As it says in the note for
30.4.3.1.10: "NOTE: Runts usually indicate collision fragments,a normal
network event."
We ran the round trip delay budget to its limits to get the 4 repeater 5
segment so there isn't an event longer than a collision fragment and shorter
than a legal frame.
It is short events that are an error condition. These are shorter than the
minimum collision fragment size should be and normally would indicate a
noise hit.
In any case, runts don't apply to 10 Gig. They are only measured in the
repeater object class and 10 Gig doesn't have repeaters.
Regards,
Pat
-----Original Message-----
From: Geoff Thompson [mailto:gthompso@xxxxxxxxxxxxxxxxxx]
Sent: Sunday, April 29, 2001 6:53 PM
To: Jamal Elsaadi
Cc: stds-802-3-hssg@xxxxxxxx
Subject: Re: aRunts
At 06:41 AM 4/28/01 -0700, Jamal Elsaadi wrote:
aRunts, what is this variable means ?
See the definition below taken from Clause 30.
This is an error condition.
In a CSMA/CD network there is a window of event size that "shouldn't
happen". That is, the event is longer than a legal collision fragment and
smaller than a legal frame. If you are going to try to have all carrier
events reported in 10 Gig and use the same buckets that are used at lower
speed (so that you can use the same management) then you gotta have it
included.
30.4.3.1.10 aRunts
ATTRIBUTE
APPROPRIATE SYNTAX:
Generalized nonresettable counter.This counter has a maximum increment rate
of 75 000 counts
per second at 10 Mb/s
BEHAVIOUR DEFINED AS:
Increment counter by one for each CarrierEvent that meets one of the
following two conditions.
Only one test need be made.
a)The ActivityDuration is greater than ShortEventMaxTime and less
than ValidPacketMinTime and the CollisionEvent signal is deasserted.
b)The OctetCount is less than 64,the ActivityDuration is greater
than ShortEventMaxTime,and the CollisionEvent signal
is deasserted. For 10 and 100 Mb/s repeaters,ValidPacketMinTime is greater
than or equal to 552 BT and less than 565 BT.A CarrierEvent greater than or
equal to 552 BT but less than 565 BT may or may not be counted as a runt.At
10 Mb/s an event whose length is greater than 74 BT but less than 82 BT
shall increment either the aShortEvents attribute or the aRunts
attribute,but not both.ValidPacketMinTime has tolerances included to provide
for circuit losses between a
conformance test point at the AUI and the measurement point within the state
diagram.
For 1000 Mb/s repeaters,ValidPacketMinTime is 4136 BT.
NOTE: Runts usually indicate collision fragments,a normal network event.
In certain situations associated with large diameter networks a percentage
of runts may exceed ValidPacketMinTime.;