Will we ever run out of MAC address??

[Cooky]

When we were running out of IP addresses, NAT and IPv6 solved the problem. How about MAC addresses?? There are so many new computers being built everyday, or should I say, new NICs being built; aren't we gonna run out of MAC addresses?? How do the manufacturers know what range of MAC they get to use anyway?? Is there an agency that has a table of all the MAC addresses so that there won't be any conflict??

 

[Tallgeese]

Originally posted by: Cooky
There are so many new computers being built everyday, or should I say, new NICs being built; aren't we gonna run out of MAC addresses?? How do the manufacturers know what range of MAC they get to use anyway?? Is there an agency that has a table of all the MAC addresses so that there won't be any conflict??

Here's a good place to start: IEEE OUI and Company_id Assignments

Several years ago, back when Apple released their original PowerMac machines, it was discovered that an engineering error had basically flipped the MAC addresses of the built-in Ethernet adapters, and the machines were using addresses that Apple did NOT own.

Luckily for them, the address ranges were not owned by anyone yet, and they were able to request and register them, albeit at a VERY hefty sum (since the last digits spanned MANY more ranges than would have initially been the case had the order been correct).

Would have HATED to have been the Jenkins responsible for that one.

BTW: "Jenkins" refers to the hapless employee portrayed in movies, tv shows, and commercials who always seems to be the reason for some major snafu, at which point the boss yells "JENKINS! IN MY OFFICE!"

 

[Fatt]

IPv6 addresses the hardware address problem as well.

They add a set of null characters well, zeros...) in front of the current MAC address that will act as place holders at first and eventually will be replaced by other numbers when needed.

 

[GigaCluster]

AFAIK, even if we run out of MAC addresses and reuse numbers, it's absolutely no big deal thanks to proxy ARP, unless by some unfortunate miracle there are identical MACs on the same network.

 

[Hanpan]

I am not 100% sure but assuming there are no restricted mac addresses there are 256^6 or 281474976710656 unique combinations.
That is over 280 trillion unique adresses. Also I am not sure if it is possible but if we added a 7th hex pair we would have 256^7 or over 72 quadrillion mac addresses.