nanog mailing list archives
Re: BCP for Private OUI / address assignments?
From: Mark Smith <nanog () 85d5b20a518b8f6864949bd940457dc124746ddc nosense org>
Date: Tue, 25 Nov 2008 07:31:52 +1030
Hi, On Mon, 24 Nov 2008 19:35:07 +0100 Peter Dambier <peter () peter-dambier de> wrote:
I also found this one helpful http://www.iana.org/assignments/ethernet-numbers === The CFxxxx Series RFC 2153 describes a method of usings a "pseudo OUI" for certain purposes when there is no appropriate regular OUI assigned. These are listed here. CF0001 Data Comm for Business [McCain] === I remember we had IBM Token-Ring equipment and they suggested to always use "CF..." and never rely on the programmed MAC for SNA.
On an ethernet network, CF is a multicast destination address, or, as a source, I'm pretty sure it indicates that the frame contains a source route for use with translational bridging. The locally assigned 0x02 bit would be better to use. Be aware that Microsoft have decided to "reserve" some locally assigned addresses in the range 02-BF, and 02-01 through 02-20 for use with their load balancing / high availability product, rather than use one of their proper OUIs. Apparently you're not supposed to be using these address ranges because the locally assigned address space is so large, before you use this Microsoft product, so if you are, too bad. You'll have to change your previous local assignments, or somehow change Microsoft's software. Within Wireshark it shows it as used by Microsoft, which implies official assignment to Microsoft. The Wireshark people won't change it, so that gives it a level of legitimacy. I think that's a slippery slope. (It's a pet hate of mine that certain organisations force their private address space assignments (RFC1918 or IEEE locally assigned) on outsiders. It's supposed to be private so outsiders don't see it or don't have to work around it!) Regards, Mark. -- "Sheep are slow and tasty, and therefore must remain constantly alert." - Bruce Schneier, "Beyond Fear"
Current thread:
- BCP for Private OUI / address assignments? mike (Nov 24)
- Re: BCP for Private OUI / address assignments? Dale W. Carder (Nov 24)
- Re: BCP for Private OUI / address assignments? Peter Dambier (Nov 24)
- Re: BCP for Private OUI / address assignments? Mark Smith (Nov 24)
- Re: BCP for Private OUI / address assignments? Deepak Jain (Nov 24)
- Re: BCP for Private OUI / address assignments? isabel dias (Nov 25)
- Re: BCP for Private OUI / address assignments? Peter Dambier (Nov 24)
- Re: BCP for Private OUI / address assignments? Dale W. Carder (Nov 24)