[187964] in North American Network Operators' Group
Re: Duplex negotiation over 100Base fibre
daemon@ATHENA.MIT.EDU (Nitin Mehrotra)
Mon Feb 29 21:30:59 2016
X-Original-To: nanog@nanog.org
From: Nitin Mehrotra <nmehrotra@riorey.com>
To: Jason Lixfeld <jason+nanog@lixfeld.ca>, NANOG <nanog@nanog.org>
Date: Mon, 29 Feb 2016 16:48:15 +0000
In-Reply-To: <7024EEDA-5401-4470-B944-89DC33647DE1@lixfeld.ca>
Errors-To: nanog-bounces@nanog.org
From all my observations, if both ends are 100Base-LX (or BX or T) and are =
set to auto-negotiate then they will negotiate to full-duplex. If one end i=
s manually configured for full duplex and the other end is configured as au=
to then that end _may_ end up as half-duplex.=0A=
=0A=
This is particularly true when connecting a 1G port to a port configured as=
100M full-duplex port. If the 1G is configured for auto-speed then it _wil=
l_ negotiate to 100M half-duplex resulting in traffic impact.=0A=
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HTH,=0A=
=0A=
Nitin=0A=
=0A=
=0A=
________________________________________=0A=
From: NANOG <nanog-bounces@nanog.org> on behalf of Jason Lixfeld <jason+nan=
og@lixfeld.ca>=0A=
Sent: Monday, February 29, 2016 11:07 AM=0A=
To: NANOG=0A=
Subject: Duplex negotiation over 100Base fibre=0A=
=0A=
Hello,=0A=
=0A=
My understanding is that for 1G and 10G optical networks, there is no conce=
pt of half-duplex mode, but I=92m unclear about half duplex in the 100M opt=
ical world. Specifically, if I connect two 100Base-LX (or BX) transceivers=
together, is there a requirement for the controller(s on either side) to s=
elect between full or half duplex, either by static configuration, or auto-=
negotiation?=0A=
=0A=
Thanks!=0A=
=0A=
