Talk:MAC address

Excellent work, but nothing on LAA, UAA or BIA and nothing on unicast, multicast, broadcast and functional addresses of frames! I've added all of these things, and some other articles - Ta bu shi da yu 12:18, 28 Jul 2004 (UTC)

Locally Assigned Addresses

The IEEE has assigned some OUIs with the 0x020000 bit set. Can anyone create and/or use a LAA OUI in MAC addresses on their LAN? --Jakllsch 19:37, 23 March 2006 (UTC)

Uniqueness

i want to ask one thing...when MAC address is unique for all networked machines...why do they need an IP address at all?

They are unique (well, almost) but the heirarchy under which they're organised is useless for routing. Your ethernet card's MAC address says "I'm a txp9000, made by XYZ Semiconductor". A machine on the other side of the world that wanted to send you a packet wouldn't know how to route that packet. By contrast, IP addresses are heirarchical by route (very very roughly). So if the remote machine sends a packet to 66.1.94.133 its router can look up a table that says "send all 66.1.x.x packets to router at 66.1.0.1". This way the remote router doesn't need to know the (impossibly long) list of exact IP addresses in your company or school - it only needs to know who is responsible for that "block" of IP addresses. It can do this because IP addresses are heirarchical by location in the wiring plan, whereas MAC addresses are only heirarchical by manufacturer (and don't tell you where on the network a given node is). -- John Fader (talk | contribs) 18:13, 22 Apr 2005 (UTC)

OS X

Can someone figure out if you can actually change a MAC address in OS X and update that section? Right now it looks quite silly. It says something like 'theoretically this should work, but i don't know nor am I motivated enough to check'

Burned in addresses

Currently, the article states

MAC addresses permanently attached to a product by the manufacturer are known as "burned-in addresses" (BIA) or sometimes as "Universally Administered Addresses" (UAA). The BIA can be overridden with a "Locally Administered Address" (LAA).

Does this mean that if one uses one of the methods to change the MAC address explained later in the article, one is using a LAA? Also, the article on burned-in address seems to disagree with the above statement; it states that there are two types of BIAs, namely UAAs and LAAs. AxelBoldt 22:24, 27 May 2005 (UTC)

No, it means that if one changes the MAC address, one is supposed to use an LAA instead of a UAA. I doubt it ever occurred to the designers of MAC-48 at the time that one would deliberately use the BIA of one station on a different station; after all, ‘they are just numbers and have no commercial significance’. 121a0012 01:52, May 28, 2005 (UTC)

Internal format of MAC

There is some formats of MAC addresses, I've read about them in "Computer Networks" by Andrew Tanenbaum.

Myth about why 48 bits were chosen

For years I have been repeating something I heard somewhere: that the inventers of the Ethernet decided there should be enough MAC addresses to uniquely identify every 5-kilogram piece of the earth. Tonight I finally did the math for myself. (Thanks, Google, for programming the "mass of earth" into your calculator as a constant.) Google says the mass of the Earth / (2^48) = 2.12246221 × 10^10 kilograms. Not even close. The best source I found for the real story (using a quick Google search) is, "John Schoch, a former PARC researcher, ... notes that PARC ... gave [Ethernet] a ridiculously large 48-bit addressing scheme—far more than anyone imagined would be needed at the time." [1] <>< tbc 06:21, 20 December 2005 (UTC)

Confused About Terminology

Why is the term 'medium access control address' used by many sources (including the IEEE) but not used or referred to by this article? I'm confused as to the difference (if any) between this term and 'media access control address'. 216.166.159.185 06:14, 23 December 2005 (UTC) M. Glenn Lewis

That's a great question - When referring to the MAC address, there is no difference between media and medium access control address. Technically media is the plural form of medium but the IEEE standards appear to use media and medium for different parts of the standard. I'll research this soon and update the article as necessary to clarify. Sfisher 05:08, 25 December 2005 (UTC)

Found it; per IEEE standard 802 "Overview and Architecture" from 2001, medium and media are interchangable in the MAC abbrevation and that standard uses medium. Sfisher 20:22, 2 January 2006 (UTC)

Fixed finding MAC under Windows XP

The instructions for finding the MAC address under Windows XP recommended using arp -a, which shows the MAC of other machines on the Local Area Network. The command ipconfig/all shows the MAC address for all network devices. David Harbaugh

"Changing the MAC address" section

The whole section is not encyclopedic and should be removed. 121a0012 18:18, 7 May 2006 (UTC)

Required by the F.C.C.?

Every once in a while I hear some schpiel about network cards having MAC addresses is because the FCC requires it, usually claimed by people who know nothing about computers.

Googling around a few minutes all I see is similar hear-say.

I'm leaning toward the this-is-a-wives-tale opinion, but I thought I'd just get confirmation anyway. I see mention of the IEEE handing out MAC addresses on the Network card article, so maybe this is what people think of -- most laymen don't know what the IEEE is or that it even exists, are so maybe they got confused with the FCC considering it's a more "well-known" entity. --I am not good at running 08:48, 19 May 2006 (UTC)