Date: Fri, 29 Aug 2008 00:44:37 -0700 From: Jeremy Chadwick <koitsu@FreeBSD.org> To: Zaphod Beeblebrox <zbeeble@gmail.com> Cc: freebsd-stable@freebsd.org, Jonathan Bond-Caron <jbondc@gmail.com> Subject: Re: IPMI and Dell ERA/O Message-ID: <20080829074437.GA67295@icarus.home.lan> In-Reply-To: <5f67a8c40808282317nd523102qae37ec584f3c0d2@mail.gmail.com> References: <004701c90998$c9d70240$5d8506c0$@com> <5f67a8c40808282317nd523102qae37ec584f3c0d2@mail.gmail.com>
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On Fri, Aug 29, 2008 at 02:17:17AM -0400, Zaphod Beeblebrox wrote: > Curiously, IPMI shares the ethernet ports with the onboard ethernet > controllers without FreeBSD's knowledge. It does use a different MAC > address. It is also apparently capable of using vlans (haven't tested this > yet). I'm most nervous about how this might behave if the port was being > nailed with traffic --- but I can't easily test this to my satisfaction. > What controls the contention for the port between whatever IPMI magic is > going on and the OS use of the port? My general opinion is to avoid IPMI at all costs. The concept itself is great, and the design idea is okay, but the implementation is an atrocity. If you *must* use IPMI, get an implementation that uses its own, dedicated NIC. That said, the feature you're referring to (IPMI piggybacking on top of an existing NIC on the mainboard) is called "ASF" from a NIC driver perspective. The NIC driver for the OS *must* have full awareness of said piggybacking, and if it doesn't, a couple different things can happen: a) NIC simply does not work b) NIC works, but behaves oddly -- usually this is tracked down to the local network seeing the MAC address continually change for the IP address associated with the machine c) NIC works, but IPMI and other features do not work There are a couple different drivers for FreeBSD which have ASF knowledge; bge(4) does, and I believe em(4) does (I could be wrong here). bge(4) has a loader.conf tunable that tells the driver to understand ASF or not. In general, it's horrible, and I feel sorry for driver authors having to deal with it. -- | Jeremy Chadwick jdc at parodius.com | | Parodius Networking http://www.parodius.com/ | | UNIX Systems Administrator Mountain View, CA, USA | | Making life hard for others since 1977. PGP: 4BD6C0CB |
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