From owner-freebsd-stable Fri Jun 8 8:17:40 2001 Delivered-To: freebsd-stable@freebsd.org Received: from prism.flugsvamp.com (cb58709-a.mdsn1.wi.home.com [24.17.241.9]) by hub.freebsd.org (Postfix) with ESMTP id 4958C37B403 for ; Fri, 8 Jun 2001 08:16:11 -0700 (PDT) (envelope-from jlemon@flugsvamp.com) Received: (from jlemon@localhost) by prism.flugsvamp.com (8.11.0/8.11.0) id f58FFSO60100; Fri, 8 Jun 2001 10:15:28 -0500 (CDT) (envelope-from jlemon) Date: Fri, 8 Jun 2001 10:15:28 -0500 (CDT) From: Jonathan Lemon Message-Id: <200106081515.f58FFSO60100@prism.flugsvamp.com> To: kenm@icarz.com, stable@freebsd.org Subject: Re: auto-negotiate/auto-detect was Re: Any patch for fxp driver? X-Newsgroups: local.mail.freebsd-stable In-Reply-To: References: Organization: Cc: Sender: owner-freebsd-stable@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG In article you write: >Hi Tom, > I have noticed a problem running my Dell with fxp0: Pro10/100B/100+ Ethernet>. If I use use mediaopt full-duplex, >suddenly I start losing packets sometimes with ping! I don't notice >mush of a problem in running except that the program "netsaint" which >pings my other servers starts telling me I am losing packets (usually >1 of 5 is lost)! (It runs ping from a forked process, then in a shell >(with spopen() ) . If I take out the mediaopt all runs well again >(with just media 100baseTX) and it also works with full auto >negotiation. This sounds like a duplex mismatch; where the other end is using half-duplex. If the autonegotiation only results in "100BaseTX", without the "" entry, then you are running half-duplex. "Autoselect" is somewhat of a misnomer, it should really be "autonegotiate". With this setting, the hardware participates in a protocol designed to get both sides to agree on a common setting. Both ends of the link are required to advertise settings they are capable of, performing and then agree on the best setting. Problems come in when: 1. One side is set for 'autonegotiate', and the other side is not. This results in the side that is doing 'autonegotiate' basically attempting to guess what the other side is doing, and possibly getting it wrong. 2. Some vendors screwing up the autonegotiate protocol and not selecting the "best" setting. A commonly seen error is where the switch decides to use half-duplex instead of full-duplex, even if both sides advertise they are full-duplex capable. The bottom line is that the settings on both sides of the link should match. If setting both sides to "auto" results in a half-duplex link, then *both* sides should be hardwired to use full-duplex instead, assuming of course, that the hardware is capable of this. -- Jonathan To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message