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Date:      Thu, 8 May 2014 12:08:28 +0000
From:      "Bjoern A. Zeeb" <bzeeb-lists@lists.zabbadoz.net>
To:        Eygene Ryabinkin <rea@freebsd.org>
Cc:        net@freebsd.org
Subject:   Re: Allowing CARP to use arbitrary OUI prefix and allocating block from FreeBSD's OUI space assignment for that
Message-ID:  <1B71A1AC-8A85-415D-A413-CD01635B3123@lists.zabbadoz.net>
In-Reply-To: <ht5ioSVMkYjTNaadctX3apO0nWQ@dHhGgwofm7uNfL6/X5%2BbGIkDUYs>
References:  <Nlrr646yWAdJ7EfNj9z5ymwq5ZQ@dHhGgwofm7uNfL6/X5%2BbGIkDUYs> <97B3C7CB-3E64-4FE0-81C8-F1FE6FB456A2@lists.zabbadoz.net> <ht5ioSVMkYjTNaadctX3apO0nWQ@dHhGgwofm7uNfL6/X5%2BbGIkDUYs>

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On 08 May 2014, at 09:50 , Eygene Ryabinkin <rea@freebsd.org> wrote:

> No, we're conflicting with VRRP on the MAC address space.
>=20
> And, as I understand, CARP in 10 hadn't changed protocol in any way,
> it just refurbished now CARP instances are configured and attached to
> the interfaces.  Could be wrong here, though.

Yes, that is why the problem remains.

=
http://svnweb.freebsd.org/base/head/sys/netinet/ip_carp.h?annotate=3D25308=
7#l86
#define CARP_VERSION            2

vs.

RFC 3768, Virtual Router Redundancy Protocol (VRRP),  5.3.1.  Version

   The version field specifies the VRRP protocol version of this packet.
   This document defines version 2.

*boom*

And the world is moving on ...

RFC 5798, Virtual Router Redundancy Protocol (VRRP) Version 3 for IPv4 =
and IPv6, 5.2.1.  Version

   The version field specifies the VRRP protocol version of this packet.
   This document defines version 3.


So, document CARP as Version 4 and then you have your own version of the =
protocol and a good reason to change the EUI-48 assignment within the =
IANA OUI maybe, maybe not.

=
http://www.iana.org/assignments/ethernet-numbers/ethernet-numbers.xhtml#et=
hernet-numbers-1

00-01-00 to 00-01-FF	VRRP (Virtual Router Redundancy Protocol)	=
[RFC5798]
00-02-00 to 00-02-FF	VRRP IPv6 (Virtual Router Redundancy Protocol =
IPv6)	[RFC5798]



Currently we are on Version 2 and VRRP (3768) is Version 2 and we share =
the OUI but speak a different language.  *boom*


Currently you are worried that =93CARP" !=3D =93VRRP" and still uses the =
same EUI-64.  But that=92s a management problem.  Server guys run =
Solaris and VRRP[1] in the Solaris group, and Linux and VRRP in the =
Linux Group, or FreeBSD and VRRP (yes people do) in the group that tries =
to talk to the other two.  If they don=92t talk to each other and the =
networking guys put the servers in the same subnet, they probably =
conflict.  *boom*   Needless to say that if they don=92t tell the =
networking guys they conflict with the routers as well *boom*boom*

Two different networking groups do redundancy failover and years later =
connect their routers;  4 routers run VRRP, same VRID by default.  =
*boom*

The samples you can find are plenty.

People need to talk.   The fact that your server guys use a non-unique =
Ethernet address for CARP without talking to their local authority who=92s=
 in charge of the network first is nothing you can fix changing the =
number.   The fact that multiple deployments on the same subnet might =
exist is nothing a number change will fix.   I think the RFC uses the =
word =93coordinate=94.


The thing you can change is to fix the version number for CARP, document =
the protocol (so your network guys become more aware of it though they =
probably won=92t anyway);  then you can make sure it doesn=92t conflict =
on as much as is possible with it---just that you cannot always (as =
described above) without talking.    So it=92s about minimising the =
impact, reading your log files, and talking to people.


[1] =
http://docs.oracle.com/cd/E23824_01/html/821-1453/gkfjq.html#scrolltoc


=97=20
Bjoern A. Zeeb             "Come on. Learn, goddamn it.", WarGames, 1983




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