From owner-freebsd-net Tue May 9 2:50:29 2000 Delivered-To: freebsd-net@freebsd.org Received: from bells.cs.ucl.ac.uk (bells.cs.ucl.ac.uk [128.16.5.31]) by hub.freebsd.org (Postfix) with SMTP id 3CAA137B940 for ; Tue, 9 May 2000 02:50:26 -0700 (PDT) (envelope-from T.Pagtzis@cs.ucl.ac.uk) Received: from ginger.cs.ucl.ac.uk by bells.cs.ucl.ac.uk with local SMTP id ; Tue, 9 May 2000 10:50:15 +0100 Message-ID: <3917DF55.9ABD99AD@cs.ucl.ac.uk> Date: Tue, 09 May 2000 10:50:14 +0100 From: Theo PAGTZIS Reply-To: t.pagtzis@cs.ucl.ac.uk Organization: UCL X-Mailer: Mozilla 4.72 [en] (X11; U; SunOS 5.7 sun4u) X-Accept-Language: el, en MIME-Version: 1.0 To: freebsd-net@freebsd.org Subject: Question on Tx queueing internals Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-freebsd-net@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org Hi all, I have been trying to understand the internals of an Ethernet driver but cannot answer the following questions, so any help on that would be appreciated. I am told that on the network card there is a Tx and Rx buffer.... Is the output queue of an interface driver the same thing as a transmit buffer on the actual network card or are they two different things...ie when the ip_output passes the packet to the if_output function of the Ether interface, the if_output will add the Ether header and then put it on the output queue (if_snd). Is this output queue (the driver's output queue ) the same as what one call the Tx/Rx buffer on the network card or are is it a different one? Also is the Tx buffer a different piece of memory than the Rx buffer on the Ethernet card. I am asking that trying to understand whethe Tx and Rx share a single buffer on the card so that Tx buffer could starv Rx buffering... Last, is a wireless network card full duplex? Thanks Theo To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message