Re: [alto] How Data Center Virtualization influence ALTO mechanism.

[Lars Eggert <[e-mail]>]

Hi,

On 2010-10-9, at 10:18, Y.J. GU wrote:
> In Data Center operation, one basic consensus is 'When Virtual Machines move from one site to another, the IP Addresses will not change, so that the existing service connection will not be broken'.

inside one data center, sure. Maybe even across data centers, with PI space and a coordinated route update. But I don't think that'd common practice.

>  VMs can migrate to arbitrary site, not under the control and knowledge of ISP. For example, some VMs in Data Center A(IP subnet 198.1.1.0) move to Data Center B (IP subnet 210.1.1.0).

Huh? Didn't you just say above that the IP addresses wouldn't change?

> IP-based, Vms are closer to DC-A. Physically, these VMs are much closer to hosts in DC-B. However things are not so easy, especially considering how these VMs are routed. Current ALTO may give wrong cost ranking.

If you're moving VMs around in the topology, you'll have to update the announced ALTO information as you do that. 

But since ALTO merely "provide(s) applications with information to perform better-than-random initial peer selection" - a direct quote from the charter - inaccurate or incorrect ALTO information is not catastrophic anyway.

Lars