James Carlson wrote: > Sunay Tripathi writes: >> James Carlson wrote: >> > What are the administrators actually doing with these MAC addresses >> > that causes them to prefer failure? >> > >> >> Factory assigned MAC addresses are inventoried entities in some >> companies. They keep track of the MAC address(s) the machine has along >> with other information (like physical location etc). Sparc's have a >> hostid but on x86, this is the only unique way to identify the physical >> machines from the packet on the network. > > Sure. And you can tell which address you've got (if you care) by > using the status command. > > And I'd point out that after any move, you would *need* to look at the > address on the interface, because the new physical interface likely > has a different set of MAC addresses on it, and you're going to need > to update those crufty tables (such as /etc/ethers). > > I'd even see no problem with issuing a warning when the > use-random-fallback event occurs: > > Warning: you asked for a factory address, but I couldn't get > one. I've assigned a random address instead. If that's not > ok, then you'll probably want to reconfigure this interface. > > (Or perhaps something more professional-looking than that.)
Huh? The guy only wants to deal with factory assigned MAC address and you would still assign a random MAC address and create a VNIC?? What does the guy do after that? Run delete-vnic since he doesn't want it in the first place? I was with you till earlier email that there might be a better way of expressing the requirement that I am only interested in factory assigned mac addresses and *don't* want to deal with random or user created things. But assigning a random MAC address when he asked for factory is almost ignoring the request. > The problem I have is with the failure mode. I don't see a purpose. Perhaps if you try to understand the difference between a unique identifier (factory MAC) that is inventoried vs a randomly generated non-unique identifier, it will be clear to you. > >> Random MAC addresses are random at best and have no guarantees that >> they are unique across different machines. The virtualization crowd >> has adopted random mac address but a sizable set of customers are >> still skeptical about duplication etc. > > I understand why users would want to prefer factory addresses. I > wasn't questioning that at all. > > I don't understand why they would prefer to see failure. It doesn't > seem helpful. Failure happen all the time when you run out of resources. We fail a process creation when we are out of memory? We fail a socket open when we run out of descriptors ... > Would users actually be inconvenienced if an interface worked because > it fell back to a random address, where they'd actually have an > advantage if it failed instead? Yes. And yes. When they see a packet on the wire, they need to know which physical machine is sending the packet and what is its location. HTH. Sunay -- Sunay Tripathi Distinguished Engineer Solaris Core Operating System Sun MicroSystems Inc. Solaris Networking: http://www.opensolaris.org/os/community/networking Project Crossbow: http://www.opensolaris.org/os/project/crossbow
