From owner-freebsd-hackers Fri Sep 28 6:53: 4 2001 Delivered-To: freebsd-hackers@freebsd.org Received: from duke.cs.duke.edu (duke.cs.duke.edu [152.3.140.1]) by hub.freebsd.org (Postfix) with ESMTP id 44ABC37B405 for ; Fri, 28 Sep 2001 06:53:01 -0700 (PDT) Received: from grasshopper.cs.duke.edu (grasshopper.cs.duke.edu [152.3.145.30]) by duke.cs.duke.edu (8.9.3/8.9.3) with ESMTP id JAA11236; Fri, 28 Sep 2001 09:52:45 -0400 (EDT) Received: (from gallatin@localhost) by grasshopper.cs.duke.edu (8.11.3/8.9.1) id f8SDqIL88765; Fri, 28 Sep 2001 09:52:18 -0400 (EDT) (envelope-from gallatin@cs.duke.edu) From: Andrew Gallatin MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <15284.32914.874966.260722@grasshopper.cs.duke.edu> Date: Fri, 28 Sep 2001 09:52:18 -0400 (EDT) To: tlambert2@mindspring.com Cc: Jonathan Lemon , the_srinivas@hotmail.com, hackers@freebsd.org Subject: Re: TCP&IP cksum offload on FreeBSD 4.2 In-Reply-To: <3BB42E50.B32F5E95@mindspring.com> References: <200109270157.f8R1vZ546863@prism.flugsvamp.com> <3BB42E50.B32F5E95@mindspring.com> X-Mailer: VM 6.75 under 21.1 (patch 12) "Channel Islands" XEmacs Lucid Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG Terry Lambert writes: > Jonathan Lemon wrote: > > >I'm trying to use the TCP&IP checksum offload capability of the Netgear > > >GA620 NIC from a SMP FreeBSD 4.2R system running on a typical PIII SBC. <..> > > He didn't say his packet size, either. > > To the original poster: if you are sending jumbograms, the > buffer size on these cards is limited, so the entire packet > can't be in the card buffer at the same time, which means > that you can not offload the send checksum for jumbograms, > only for regular sized packets. This is an Alteon Tigon-2 (ti driver) based card with 512K of sram on board. It has plenty of space for offloading transmit checksums on jumbo frames. Perhaps you're thinking of the DP83820/DP83821 (nge driver), which cannot compute the checksum on an outgoing frame unless it fits in the 8K tx fifo. I think NetGear sells a card with a similar name (GA622T) based around this chip. Drew To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message