[192912] in North American Network Operators' Group
Re: Forwarding issues related to MACs starting with a 4 or a 6 (Was:
daemon@ATHENA.MIT.EDU (Nick Hilliard)
Fri Dec 2 11:59:44 2016
X-Original-To: nanog@nanog.org
X-Envelope-To: nanog@nanog.org
Date: Fri, 02 Dec 2016 16:59:37 +0000
From: Nick Hilliard <nick@foobar.org>
To: Job Snijders <job@instituut.net>
In-Reply-To: <20161202143213.GT513@Vurt.local>
Cc: nanog@nanog.org
Errors-To: nanog-bounces@nanog.org
Job Snijders wrote:
> Dear IEEE, please pause assigning MAC addresses that start with a 4 or a
> 6 for the next 6 years.
Disagree that this is an IEEE problem. This is problem that vendors
need to work around. There is limited MAC space, and deprecating 1/8 of
it due to the inability of vendors to cope properly with it seems like a
really bad long term idea.
It seems that the problem that cropped up on cisco-nsp is that a layer 2
switch, the Nexus 92160 (and possibly everything else which uses the
same forwarding ASIC), cannot forward vpls frames with a 4 or 6 buried
at a specific location inside the contents of the frame.
This is an extraordinary bug which renders the hardware useless in
specific circumstances. What makes it worse is that this is a well
known corner case which should have been shaken out during design, if
not found during QA.
Nick
