[dc] 答复: Re: Requirement for a method to manage mac address in DC

Hi Mallik:
        I learned about that Xen generate MAC address by an algorithm base 
the timestamp.
I don't know well about other virtualization platform.
        As you say that:  
> There is some notion of Management-Entity(s)/controller(s) allocating 
the 
> MAC addresses for VMs and ensures that it does not assign the same MAC 
> address to two different VMs and this work only within the scope of that 

> management/controller administration.

why does it work only within the scope of that management/controller 
administration?
How do VMs get the MAC addresses?
Could you please elaborate?

>-----------------------------------------<
¨q¡Ð¨r¡è¡¡¡¡¡¡¡¡¡¡     Innovation change 
                          the world 
¨q¨q ¡Ð¨r        ¡ñ¨q¡ð¨r¡¡ 
¨t ----¨s       /¨¡Å¨\ ¡¡
~~~~~~~~~~~~~~~~~¡Ç~~¡Ç~~~~~~~~~~~~~~~~~
           My nickname: Fisher Yu
>----------------------------------------<

Mallik Mahalingam <mallik@vmware.com> Ð´ÓÚ 2012-02-03 03:21:56:

> In a virtualized environment MAC addresses are not totally random 
generated. 
> There is some notion of Management-Entity(s)/controller(s) allocating 
the 
> MAC addresses for VMs and ensures that it does not assign the same MAC 
> address to two different VMs and this work only within the scope of that 

> management/controller administration. There are some exceptions of 
course 
> (a) MAC address exhaustion under a given OUI category  (b) manual 
> copy/cloning of VMs and powering on them using standalone management 
> entities (c) VMs that use MAC address override for legitimate reasons 
> [because else things like licensing software breaks].  There are some 
> mechanisms in place to address (a), but (b) and (c) requires 
co-operation at 
> the management-entity/controllers.
> 
> Mallik
> 

> From: "Truman Boyes" <tboyes@gmail.com>
> To: "Thomas Narten" <narten@us.ibm.com>
> Cc: "yu jinghai" <yu.jinghai@zte.com.cn>, dc@ietf.org, "Lizhong Jin"
> <lizho.jin@gmail.com>
> Sent: Thursday, February 2, 2012 10:20:07 AM
> Subject: Re: [dc] Requirement for a method to manage mac address in DC
> 
> 

> On Thu, Feb 2, 2012 at 10:55 AM, Thomas Narten <narten@us.ibm.com> 
wrote:
> Truman Boyes <tboyes@gmail.com> writes:
> 
> > The L2 separation between multiple tenants is true in most 
circumstances in
> > DCs, but in commodity computing (ie. VPS, low cost dedicated servers, 
or
> > co-location) there is a concern on IPv4 address exhaustion or waste, 
so
> > machines/instances are grouped on single L2 segments. It is possible 
to
> > have virtual MAC overlaps on these segments. Is this something that 
this
> > group wishes to evaluate options to solve?

> IMO, this is putting the cart before the horse.
> 
> Can we first get a sense for how big a problem this is in practice and
> whether existing mitigation approaches are not sufficient?
> 
> I.e., is this a real problem causing significant pain today, or are
> their other bigger "pain points" that we should be looking at?
> 
> Thomas

> 
> In the VPS/VM world,  I would say it's not a significant issue 
> because there are single entities (Organizations) that manage the 
> MAC addresses. Typically software would just increment the virtual 
> MACs, and this does not require external protocols to ensure 
> uniqueness. If there are many provisioning systems that manage VMs 
> on the same network segment then they will need to keep their 
> database in sync. 
> 
> -- 
> --truman
> 
> 
> _______________________________________________
> dc mailing list
> dc@ietf.org
> https://www.ietf.org/mailman/listinfo/dc