"illegal" or reserved MAC address ?

Like IP address 10.x.x.x;172.16-31,192.x.x.x,Anyone know what "illegal" or reserved MAC address which can not use ? (e.g 0180c2 000001 (1 to f) Does have any ieee spec. mention it?

Thanks, sy

Reply to
wld
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What do you mean by "can not use"? IP addresses like 10.x.x.x are not illegal in any useful sense. They are intended to be used - locally.

Have a look at

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- in Chapter 3.2 you'll find mention of the U/L bit within a MAC address, which determines whether a MAC address is universally assigned or locally administered. The locally administered addresses, comprising half of the whole address space, are morally equivalent to IP layer private addresses from 10.x.x.x,

192.168.x.x, etc.

best regards Patrick

Reply to
Patrick Schaaf

I see that that reference is confusing. It suggests that the U/L bit were only "valid" for some Token Ring addressing format.

Here's another one,

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for U/L in there. But that one is also confusing. They talk about every station where the administrator manually configures MAC addresses, should set the L bit. Weird, isn't it?

So, question for the group: is use of the U/L bit (set to L) legal in all ordinary Ethernets? Is there a canonical GOOD reference that gives license for such usage? Or, is it just "happens to work"?

best regards Patrick

Reply to
Patrick Schaaf

Setting the "U/L" bit to "L (local)" is valid, per IEEE 802.3 (about as good a "canon" as you are likely to get). All this means is that, for the devices so set, responsibility for unique address assignment falls on the network administrator, rather than on the manufacturer of the device.

-- Rich Seifert Networks and Communications Consulting 21885 Bear Creek Way (408) 395-5700 Los Gatos, CA 95033 (408) 395-1966 FAX

Send replies to: usenet at richseifert dot com

Reply to
Rich Seifert

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