[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] RE: [Xen-users] uniq mac address generator
On Fri, 13 Apr 2007 16:04:21 +0200, "Petersson, Mats" <Mats.Petersson@xxxxxxx> wrote: > > >> -----Original Message----- >> From: Timo Benk [mailto:timo.benk@xxxxxx] >> Sent: 13 April 2007 15:00 >> To: Petersson, Mats >> Cc: trilok nuwal; Xen list >> Subject: RE: [Xen-users] uniq mac address generator >> >> On Fri, 13 Apr 2007 15:40:45 +0200, "Petersson, Mats" >> <Mats.Petersson@xxxxxxx> wrote: >> > >> > >> >> -----Original Message----- >> >> From: Timo Benk [mailto:timo.benk@xxxxxx] >> >> Sent: 13 April 2007 14:34 >> >> To: trilok nuwal >> >> Cc: Petersson, Mats; Xen list >> >> Subject: Re: [Xen-users] uniq mac address generator >> >> >> >> Hi, >> >> >> >> > But How i can insure that mac geneareted by this script will >> >> > be uniq in whole world. Some body in the same network also >> >> > might use the same script >> >> > and can get the same mac as i am . >> >> >> >> You can add a little python to your config files. That way >> >> you can bind the MAC to the vmid parameter. The vmid >> >> code is directly extracted off the example configuration. >> > >> > But that's CERTAINLY doesn't make it unique, unless you >> also make sure >> > the rest of the numbers that make up the MAC address are >> unique to the >> > world. I also think you need to restrict your VMID to 0..255 in some >> > way, such as "and 255" or "modulo 256". [Don't know for >> sure how you do >> > that in Python]. >> >> Well, i don't think that the intention of the original author >> was to ensure >> worldwide uniqueness. >> >> But with the skript you can ensure unique MAC-Adresses inside >> you network. >> >> By changeing the prefix you can run multiple Domain-0s, each >> with a uniq >> MAC-Adress space. > > Yes, but if you start/restart/save/restore/migrate your domain(s) > sufficient number of times (and implement the modulo, otherwise you'll > just end up with a "badly formed mac-address"), you'll have a collision > every 256 VMid's. Why that? I don't think that you will have 256 running domains, and if you have such many domains, add another parameter, another prefix, whatever. vmid is not equal to the domain id, but a new xm parameter. Greetings, -timo -- Timo Benk - Jabber ID: fry@xxxxxxxxxxxx - ICQ ID: #414944731 PGP Public Key: http://www.m28s01.vlinux.de/timo_benk_gpg_key.asc _______________________________________________ Xen-users mailing list Xen-users@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-users
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