ward@hao.UUCP (Mike Ward) (05/13/84)
[]
Is it true that all Ethernet devices have a unique address, or must one
make a special effort to obtain one from some organization?
If so, what is the organization, and what are the advantages/disadvantages?
--
Michael Ward, NCAR/SCD
UUCP: {hplabs,nbires,brl-bmd,seismo,menlo70,stcvax}!hao!ward
BELL: 303-497-1252
USPS: POB 3000, Boulder, CO 80307smb@ulysses.UUCP (Steven Bellovin) (05/15/84)
All Ethernet devices have a unique address. The high-order 24 bits (well, 23, really; one's the multicast bit) are assigned by Xerox to a manufacturer, in payment for a "nominal" administrative fee. The low-order 24 bits are assigned by the manufacturer to each unit, typically by means of a PROM. These are guaranteed to be unique. In fact, at least for some manufacturers (and maybe all; I don't have my copy of the spec handy) once you buy a board with some particular address, that address is yours forevermore -- if you send the board back for repair/replacement, you may receive a new address, but they'll typically send you back your old PROM so you can use either.
rpw3@fortune.UUCP (05/16/84)
#R:hao:-96700:fortune:5900021:000:2232 fortune!rpw3 May 15 15:10:00 1984 +-------------------- | Is it true that all Ethernet devices have a unique address,... +-------------------- They'd damned well better! That's why they are 48 bits. (Although somebody somewhere will, from time to time, screw up in their manufacturing and Q/A and have to come around and fix it. ;-} ) +-------------------- | ...or must one make a special effort to obtain one from some organization? | If so, what is the organization, and what are the advantages/disadvantages? +-------------------- If you are just buying controllers from some vendor such as 3Com or Interlan, not to worry. The controller comes with a default address which is (supposed to be) unique, set by the vendor. Note: If you are going to be a gateway host between two Ethernets, make sure your controllers can have the address overridden by host software, since it is very important that the same absolute physical address appear on both nets. (Usually, you go read the default addresses from all the controllers, pick one [the smallest? the "first"?], and write that to all of them.) If you are manufacturing controllers, you will need a license from Xerox to use the Ethernet patent ($1000, one-time). With that license, you get a (LARGE!) block of numbers to use to give unique numbers to your controllers. It you just want a block of globally-unique numbers, I think Xerox will also sell you a block of Ethernet addresses (with NO patent license) for $500. There is no real advantage in getting your own addresses, as opposed to using the ones that come with your controllers. (In fact, should you write any software that depends of the manufacturer-specific 24 bits of the address, you would deserve to get your hands slapped!) In any event, for more details go to the source (Appendix "B" of the spec): Xerox Corporation Ethernet Address Administration Office 3333 Coyote Hill Road Palo Alto, CA 94304 Packet types and network numbers are also registered through the same office. (Note: ALL of IP/TCP uses merely one packet type. Ditto all of XNS/ITP.) Rob Warnock UUCP: {ihnp4,ucbvax!amd70,hpda,harpo,sri-unix,allegra}!fortune!rpw3 DDD: (415)595-8444 USPS: Fortune Systems Corp, 101 Twin Dolphin Drive, Redwood City, CA 94065
cline@bergil.DEC (Greg ) (05/16/84)
<Gone, but not forgotten> Nodes on Ethernet lines are identified by unique Ethernet addresses. A message can be sent to one, several, or all nodes on an Ethernet line simultaneously, depending on the Ethernet address used. An Ethernet address is 48 bits in length. Ethernet addresses are represented as six pairs of hexadecimal digits (six bytes), separated by hyphens (for example, AA-01-23-45-67-FF). The bytes are displayed from left to right in the order in which they are transmitted; bits within each byte are transmitted from right to left. In the example, byte AA is transmitted first; byte FF is transmitted last. Xerox Corporation assigns a block of addresses to a producer of Ethernet interfaces upon application. Thus every manufacturer has a unique set of addresses to use. Normally, one address out of the assigned block of physical addresses is permanently associated with each interface. This address is known as the Ethernet hardware address of the interface. -- Greg Cline, Digital Equipment Corporation UUCP: decvax!decwrl!rhea!bergil!cline BELL: 617-858-3202 US Snail: 1925 Andover St, Tewksbury, MA 01876
darrelj@sdcrdcf.UUCP (05/16/84)
Note that while Xerox has set up (on paper) careful administration of
address space (of several kinds: hosts, networks, protocols, courier
procedures, etc), in fact, they really aren't doing very much (I asked once
about a protocol number). They are currently depending on the large spaces
relative to needs (e.g. few people specify new protocols) rather than rigid
bureaucracy to organize things.
--
Darrel J. Van Buer, PhD
System Development Corp.
2500 Colorado Ave
Santa Monica, CA 90406
(213)820-4111 x5449
...{allegra,burdvax,cbosgd,hplabs,ihnp4,sdccsu3,trw-unix}!sdcrdcf!darrelj
VANBUER@USC-ECL.ARPAsmb@ulysses.UUCP (Steven Bellovin) (05/16/84)
From: rpw3@fortune.UUCP Newsgroups: net.lan Subject: Re: Ethernet addressing - (nf) Message-ID: <3316@fortune.UUCP> Date: Tue, 15-May-84 19:05:52 EDT Note: If you are going to be a gateway host between two Ethernets, make sure your controllers can have the address overridden by host software, since it is very important that the same absolute physical address appear on both nets. (Usually, you go read the default addresses from all the controllers, pick one [the smallest? the "first"?], and write that to all of them.) This applies only if you use the XNS protocols. Xerox's Internet protocol calls for a 16-bit network number that does not appear in the Ethernet header, plus a 48-bit host number that does. (It may appear elsewhere, but I don't have my copy of the spec handy.) This 48-bit number must be the same on all networks; hence you must override the default board address as Rob describes. If you use TCP/IP, it doesn't matter, though I suspect that there's some stuff in 4.2 that would work better if you did.
james@umcp-cs.UUCP (05/21/84)
If I've got this right, ethernet addresses are 48 bits long, and of those 48, the first 32 comprise a 4-byte manufacturer code assigned to the manufacturer (Interlan, say) by the people who rule ethernet (Xerox, am I right?). The last 16 bits are assigned (uniquely) by the manufacturer. --Jim
mac@uvacs.UUCP (06/02/84)
One suggestion made, I believe, by IEEE 802 is to assign unique network addresses by using the serial numbers on dollar bills The U.S. government already provides these unique IDs at a modest fee. One might take a dolloar bill, use the serial number as station address, and destroy the bill or tape it inside the cabinet to withdraw it from circulation.
pag@hao.UUCP (Peter Gross) (06/05/84)
> One suggestion made, I believe, by IEEE 802 is to assign unique network > addresses by using the serial numbers on dollar bills The U.S. government > already provides these unique IDs at a modest fee. One might take a > dolloar bill, use the serial number as station address, and destroy the > bill or tape it inside the cabinet to withdraw it from circulation. Sounds to me like a bureaucrat's secret plan to reduce the national debt ..... Make 'em use $100 bills, --peter gross hao!pag
faunt@saturn.UUCP (Doug Faunt) (06/05/84)
It could be free, for a small amount of work, because the serial # could be cut out, and attached to the node, and the rest of the note taken to a bank, and replaced with another whole note. I wouldn't want a negotiable note saved anyway, because somebody is likely to take it and spend it.
merlyn@sequent.UUCP (06/05/84)
Isn't "burning" a dollar bill illegal in the same way that smashing
a penny is? "Destruction of public property" and that sort of nonsense?
Besides, doesn't that add to the cost of the machine? :-}
-- A particularly personal and original observation from the thought-stream of
Randal L. ("dollar-for-dollar") Schwartz, esq. (merlyn@sequent.UUCP)
(Official Legendary Sorcerer of the 1984 Summer Olympics)
Sequent Computer Systems, Inc. (503)626-5700 (sequent = 1/quosine)dgary@ecsvax.UUCP (06/07/84)
Don't destroy the dollar bill, frame it!
(No frames prease.)
D Gary Grady
Duke University Computation Center, Durham, NC 27706
(919) 684-4146
USENET: {decvax,ihnp4,akgua,etc.}!mcnc!ecsvax!dgarymark@munnari.UUCP (06/07/84)
[] I like the idea of using the serial numbers of dollar notes, but the notes in my wallet are labelled something like KBU 394101 It seems that the US dollar hasn't got to Australia yet!? In Australia one dollar notes are being phased out and replaced with coins! This could start getting expensive. In addition, I don't know about American law, but destroying Australian currency is a federal offence. If you stick the note into the cabinet, imagine the problems if someone was short of money and borrowed it! What happens if they are honest and replace the note with another one! oh well Mark Davoren decvax!mulga!mark
jaap@haring.UUCP (06/07/84)
>> One suggestion made, I believe, by IEEE 802 is to assign unique network >> addresses by using the serial numbers on dollar bills The U.S. government >> already provides these unique IDs at a modest fee. One might take a >> dolloar bill, use the serial number as station address, and destroy the >> bill or tape it inside the cabinet to withdraw it from circulation. > >Sounds to me like a bureaucrat's secret plan to reduce the national debt ..... > >Make 'em use $100 bills, >peter gross So you have to pay an extra $100 for an unique address, whenever you buy an American Ethernet interface. It's even worse (or better). Non-American based manufacturers will need to print there own dollar bills to get an unique address. What a profit will they make! Jaap.
stephenf@elecvax.UUCP (06/07/84)
I agree that using the serial number of dollar bills is a nice idea. But if you want really unique addresses, rather than just unique within the USA, you would have to get everyone to agree on what country's currency to use. Otherwise if someone used several boards manufactured in different countries in the one Local Area Network, there would be the possibility of a conflict. Yes, there is life outside America. Stephen Frede University of New South Wales Australia ...!decvax!mulga!stephenf:elecvax PS - our dollar bills are being replaced with dollar coins. We'd have to use two dollar bills.
ed@mtxinu.UUCP (06/09/84)
Actually, defacing currency or coin isn't illegal in and of itself. Trying to *pass* defaced currency is, however. -- Ed Gould ucbvax!mtxinu!ed
rpw3@fortune.UUCP (06/10/84)
#R:uvacs:-132900:fortune:5900024:000:978
fortune!rpw3 Jun 10 02:13:00 1984
Geez, what a way to make money! I hereby announce (no I don't, it's a joke!)
a new company, called Addresses Limited, which will give you a guaranteed
unique 48-bit number suitable for use as an Ethernet address for only $5.00!!
[Let's see... my one-time fee to Xerox for 2^24 numbers is $1000, so
if I sell only 10,000 of these, that's $0.10 for each unique number.
Each postcard I send the numbers out on is $0.20 postage, the card
itself is a nickle (pretty "engraving"), the machine time to print it
is $0.02, the operator time is $0.07 (labor's expensive), and the legal
fees and liability insurance is $1.37, G & A $0.35... Gross profit = $2.89
(if my addition is correct), or 58%. Gross earnings on 10k = $28,900.
Not too shabby... Now, how do I get that SBA loan for the initial $1k?]
Rob Warnock
UUCP: {ihnp4,ucbvax!amd70,hpda,harpo,sri-unix,allegra}!fortune!rpw3
DDD: (415)595-8444
USPS: Fortune Systems Corp, 101 Twin Dolphin Drive, Redwood City, CA 94065topher@cyb-eng.UUCP (Topher Eliot) (06/10/84)
> I think there may be a law or two that makes it a crime to distroy > US currency. (It is probably something terible like a felony ... ) > > However, even if that is the case a very easy way to get your address > is to take a dollor bill and to use the serial number, then take an indelible > marker and write on the dollor bill, > > <THIS BILLS NUMBER IS BEING USED AS A NETWORK ADDRESS) > > or TBNIBUANA > > Then we just have to educate the entire comuter science > comunity not to use any numbers from bills that say TBNIBUANA on them. > A nice idea, but correct operation depends on educating the "entire comuter science comunity" (sic). So instead, I volunteer to sacrifice myself in the cause of unique network addresses: anyone can use the number on a dollor (sic) bill for a network address, and then mail that bill to me. I will destroy it, taking upon myself the full legal burden of this crime. You're welcome. Cheers, Topher Eliot Cyb Systems, Austin, TX {seismo, allegra, ihnp4}!ut-sally!cyb-eng!topher
mark@cbosgd.UUCP (Mark Horton) (06/11/84)
That's a really neat idea! As I take a dollar bill out of my wallet, I see the serial number is D 75655246 B nearby there is a "4", and to the left of the 4 is an F2. It's a 1981 note. It would be interesting if someone who knows the structure of serial numbers would comment on it. In particular, how much information do you have to include to insure the number is unique? Are the D and B necessary? The 4? The F2? The date on the bill? Can we be sure that the 8 digit numbers won't grow to 9 someday? Will the numbers ever repeat as bills are recycled? Mark