From owner-freebsd-net@FreeBSD.ORG  Tue Dec 16 18:20:42 2008
Return-Path: <owner-freebsd-net@FreeBSD.ORG>
Delivered-To: freebsd-net@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id B6ED5106568C;
	Tue, 16 Dec 2008 18:20:42 +0000 (UTC)
	(envelope-from Hartmut.Brandt@dlr.de)
Received: from smtp-1.dlr.de (smtp-1.dlr.de [195.37.61.185])
	by mx1.freebsd.org (Postfix) with ESMTP id 42BCC8FC34;
	Tue, 16 Dec 2008 18:20:41 +0000 (UTC)
	(envelope-from Hartmut.Brandt@dlr.de)
Received: from beagle.kn.op.dlr.de ([129.247.178.136]) by smtp-1.dlr.de over
	TLS secured channel with Microsoft SMTPSVC(6.0.3790.1830); 
	Tue, 16 Dec 2008 19:20:40 +0100
Date: Tue, 16 Dec 2008 19:22:45 +0100 (CET)
From: Harti Brandt <hartmut.brandt@dlr.de>
X-X-Sender: brandt_h@beagle.kn.op.dlr.de
To: Bruce Simpson <bms@incunabulum.net>
In-Reply-To: <4947EEA5.6050501@incunabulum.net>
Message-ID: <20081216191244.C74416@beagle.kn.op.dlr.de>
References: <4947D7A9.2050407@FreeBSD.org>
	<20081216181850.O74416@beagle.kn.op.dlr.de>
	<4947EEA5.6050501@incunabulum.net>
X-OpenPGP-Key: harti@freebsd.org
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
X-OriginalArrivalTime: 16 Dec 2008 18:20:40.0605 (UTC)
	FILETIME=[004FDCD0:01C95FAB]
Cc: freebsd-net@freebsd.org, Sergey Matveychuk <sem@FreeBSD.org>
Subject: Re: bsnmpd & 64bits counters problem
X-BeenThere: freebsd-net@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
Reply-To: Harti Brandt <harti@freebsd.org>
List-Id: Networking and TCP/IP with FreeBSD <freebsd-net.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-net>,
	<mailto:freebsd-net-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-net>
List-Post: <mailto:freebsd-net@freebsd.org>
List-Help: <mailto:freebsd-net-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-net>,
	<mailto:freebsd-net-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Tue, 16 Dec 2008 18:20:42 -0000

On Tue, 16 Dec 2008, Bruce Simpson wrote:

BS>Harti Brandt wrote:
BS>> The highspeed counters are only there if this is a high-speed interface.
BS>> High speed means that the baudrate in the interface MIB (the one in the
BS>> kernel) must be larger than 20Mbaud.
BS>>   
BS>
BS>Does it look at the if_baudrate member?
BS>
BS>em(4) and other drivers will set if_baudrate according to the speed detected
BS>from Ethernet link beat, this could be creating a situation where bsnmpd is
BS>not exposing the high-speed counters at runtime?
BS>
BS>I imagine this could really confuse an SNMP-oriented Network Management
BS>System such as Nagios or OpenNMS.

Yes, it looks at ifi_baudrate. The reason is that the HC counters are 
mandatory only for interfaces with > 20MBit/second according to the 
compliance statememnt of the MIB. The HC counters come add additional 
cost, because the daemon has to poll the kernel's 32 bit counters and 
detect wrap arounds. So the daemon adapts dynamically based on the 
interface with the highest speed.

And in any case, network management tools must be prepared to handle both 
cases.

See also RFC2233: For interfaces that operate at 20,000,000 (20 million) 
bits per second or less, 32-bit byte and packet counters MUST be used.

harti