Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!thunder.mcrcim.mcgill.edu!snorkelwacker.mit.edu!linus!alliant!werme
From: werme@Alliant.COM (Ric Werme)
Newsgroups: comp.dcom.lans
Subject: Re: Ethernet "heartbeat"
Message-ID: <4682@alliant.Alliant.COM>
Date: 17 May 91 15:44:54 GMT
References: <12164@uwm.edu> <1991May16.004523.21301@berlioz.nsc.com> <104479@sgi.sgi.com>
Organization: Alliant Computer Systems Corp.
Lines: 42

In article <104479@sgi.sgi.com> vjs@rhyolite.wpd.sgi.com (Vernon Schryver) writes:
>From what I've seen, while most hardware more or less supports it, all
>software ignores it.  If you write a BSD UNIX style driver, there's no
>good place to count or report missing missing heartbeats.

In Alliant's in house net, we generally disable heartbeat on all our
transceivers so that we don't have to remember to check before we plug one
into a repeater.  Heck, if you can't use it sometimes, why use it at all?

An ioctl in our CMC-130 driver does let us get to the statistics the CMC board
keeps:

marley 28% ifstats en0
Transmit data:
frames sent without errors:                             349978
frames sent despite SQE test errors:                    316660
frames sent after deferral due to active medium:         23704
frames sent after a single collision:                    10078
frames sent after multiple collisions:                    6328
frames abandoned after 16 collisions:                        0
frames abandoned due to late collision:                      1
frames abandoned due to no carrier:                          8
frames abandoned due to length > 1518:                       0
frames abandoned due to silo underflow:                      0
frames abandoned due to board level memory error:            0

Receive data:
frames received without errors:                         385372
frames received with CRC errors:                            53
frames received with alignment errors:                      50
frames lost due to no receive buffers:                      77
frames lost due to silo overrun:                             1
frames lost due to board level memory error:                 0

What I've never bothered to figure out is why the frames with SQE errors
doesn't match the number for frames sent.  It may the that the SQE test is
skipped if the board has another frame to send after one finishes.
-- 

| A pride of lions              | Eric J Werme                   |
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