From owner-freebsd-net Thu Oct 31 6:50:54 2002 Delivered-To: freebsd-net@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id C532237B401 for ; Thu, 31 Oct 2002 06:50:53 -0800 (PST) Received: from mail.sandvine.com (sandvine.com [199.243.201.138]) by mx1.FreeBSD.org (Postfix) with ESMTP id 44F5343E75 for ; Thu, 31 Oct 2002 06:50:53 -0800 (PST) (envelope-from don@sandvine.com) Received: by mail.sandvine.com with Internet Mail Service (5.5.2653.19) id <42S9VQQP>; Thu, 31 Oct 2002 09:50:52 -0500 Message-ID: From: Don Bowman To: "'freebsd-net@freebsd.org'" Subject: ng_fec hash mechanism versus cisco etherchannel Date: Thu, 31 Oct 2002 09:50:44 -0500 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2653.19) Content-Type: text/plain; charset="iso-8859-1" Sender: owner-freebsd-net@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org Examining the source code to ng_fec, in ng_fec_output(), it uses the IP address to form the hash to pick the port. This is the same behaviour that 802.3ad specifies, and yields good behaviour since: a: it works in routed environments as well as local area b: packets are not reordered within L4 sessions. However, cisco seems to imply they use a hash based on MAC: http://www.cisco.com/warp/public/cc/techno/media/lan/ether/channel/prodlit/f aste_an.htm for some devices (e.g. a cat5000). Others (e.g. cat7500, cat8500) use L3 as ng_fec does. Yet others use SA based distribution (e.g. the cat1900, 2820). Does the ng_fec interoperate with the L2 only devices of cisco? --don (don@sandvine.com www.sandvine.com) To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message