nanog mailing list archives
Re: what about 48 bits?
From: joel jaeggli <joelja () bogus com>
Date: Tue, 06 Apr 2010 00:56:55 -0400
On 4/5/2010 5:26 PM, Patrick W. Gilmore wrote:
On Apr 5, 2010, at 5:08 PM, Valdis.Kletnieks () vt edu wrote:On Mon, 05 Apr 2010 16:36:26 EDT, Jon Lewis said:Since they only really need to be unique per broadcast domain, it doesn't really matter. You can I could use the same MAC addresses on all our home gear, and never know it. For manufacturers, it's probably reasonably safe to reuse MAC addresses they put on 10mbit ISA ethernet cards...if they were a manufacturer back then.Until you buy 25 cards with the same MAC address and deploy them all across your enterpriseI don't think that's possible given that Jon was suggesting. I'm 3COM, I made ISA 10Base2 / 10Base5 cards in the 90s. I run out of MAC addresses. Instead of going to get more - if I even can! - I recycle those MAC addresses, figuring the 10GE PCI-X cards I'm making now have 0.000% chance of being on the same b-cast domain as one of those old ISA cards. Even if I am wrong, the max collision possibility is 2, not 25. Seems reasonable. If I am wrong, I'll apologize profusely, refund the price of the 10G card I gave the customer, ship him a new one free, so he gets two he can use (assuming he has more than one b-cast domain), which would probably make the customer happy. Wanna bet how many times 3COM would have to ship free 10GE cards?
3com is now HP and i doubt very much that either company would bother with that approach...
That said, the volume production run for a circa 1992 isa bus ethernet nic (or the enitre sun microsystems product line for that matter) is propably two orders of magnitude lower than say the minimum volume production of mini-pci-express wireless card that goes into a laptop, and laptops might have two or three mac addresses.
Current thread:
- Re: what about 48 bits?, (continued)
- Re: what about 48 bits? Roland Perry (Apr 08)
- Re: what about 48 bits? A.B. Jr. (Apr 04)
- Re: what about 48 bits? Scott Howard (Apr 04)
- Re: what about 48 bits? Larry Sheldon (Apr 04)
- Re: what about 48 bits? Kevin Oberman (Apr 04)
- Re: what about 48 bits? Valdis . Kletnieks (Apr 05)
- Re: what about 48 bits? Patrick W. Gilmore (Apr 05)
- Re: what about 48 bits? Valdis . Kletnieks (Apr 05)
- Re: what about 48 bits? joel jaeggli (Apr 05)
- Re: what about 48 bits? Jon Lewis (Apr 06)
- Re: what about 48 bits? Mark Smith (Apr 04)
- Re: what about 48 bits? Jim Burwell (Apr 04)
- Re: what about 48 bits? Jorge Amodio (Apr 04)
- Re: what about 48 bits? Steven Bellovin (Apr 04)
- Re: what about 48 bits? Jorge Amodio (Apr 04)