Date: Fri, 04 Aug 2000 08:42:54 -0700 From: "Kevin Oberman" <oberman@es.net> To: behanna@zbzoom.net Cc: Alexander <arap@oduurl.ru>, Ben Hacker Jr <strbenjr@yahoo.com>, list DC-FBSD <fug-washdc@Sytex.Net>, questions FBSD <freebsd-questions@FreeBSD.ORG>, Stable FBSD <freebsd-stable@FreeBSD.ORG>, Ben Hacker Jr <bhacker1@csc.com> Subject: Re: Router "ep2" issue Message-ID: <200008041542.e74FgsU32161@ptavv.es.net> In-Reply-To: Your message of "Fri, 04 Aug 2000 06:34:18 EDT." <Pine.BSF.4.21.0008040632250.95225-100000@topperwein.dyndns.org>
next in thread | previous in thread | raw e-mail | index | archive | help
> Date: Fri, 4 Aug 2000 06:34:18 -0400 (EDT) > From: Chris BeHanna <behanna@zbzoom.net> > Sender: owner-freebsd-stable@FreeBSD.ORG > > On Fri, 4 Aug 2000, Alexander wrote: > > > Ben Hacker Jr wrote: > > > > > > Hello all... > > > > > > I built a router about six months back and it has been > > > > > > working pretty good except that sometimes I will lose > > > connectivity to the subnet on one of the ports (ep2). > > > > > > I lost connectivity again today and tried to figure > > > out what > > > was going wrong. I don't know how to tell if it is > > > caused > > > by hardware or my configuration. > > > > Same problem with "ep" drivers: > > - 4x3com579(EISA) in i486DX50 > > - 3.4-STABLE FreeBSD > > - cured "ifconfig down/up" > > I suppose a ethernet problems > > Problems disapear when I disconnect new station with unnamed network > > card > > Do these problems happen during thunderstorms, perchance? > > One of my coworkers recently turned me on to the fact that the > ethernet standard requires that the NICs, and all components of the > network, be properly grounded (no, not just to the box chassis) to be > reliable. Of course, no one really does this, and most of the time > you can get away without it, but sometimes you can't. Could provide a citation for this. I can't find this anywhere in my copy of 802.3. Of course, it's a rather thick document and I could have missed something, but grounding is something that Ethernet was deliberately designed to NOT require. The spec does call for medium grounding for 10Base5 and allows for it (but does not require it) for 10Base2, but that's about it. There is full electrical isolation and transformer coupling of most signals including DC-to-DC converters for power supplies just to make SURE that the external parts of the system (MAU and medium) are floating with respect to one another. (The medium grounding requirement for 10Base5 are safety related and result from the possibility that the terminating equipment on these rather long runs might be connected to different power systems.) The only references to 'earthing' I could find refer to chassis ground and all of the grounding requirements are in parts of the spec not relevant to twisted-pair networks. R. Kevin Oberman, Network Engineer Energy Sciences Network (ESnet) Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab) E-mail: oberman@es.net Phone: +1 510 486-8634 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200008041542.e74FgsU32161>