On Oct 9, 2010, at 9:18 AM, Y.J. GU wrote:
Hi all,
I was thinking about how Data Center Virtualization and Virtual
Machine(VM) Migration will influence ALTO mechanism.
Current ALTO Protocol defines clustering of peers according to their
IP Addresses. E.g. peers in same subnet will be classified into same
PID, and path cost will indicate the cost within and between PIDs,
which is also actually based on IP Addresses.
the methods of grouping are orthogonal to ALTO protocol specification.
There are ALTO implementations that allow address/prefixes grouping
relaxed from pure IP aggregation. The fact that you use IP addresses
in the protocol doesn't mean that locality is solely based on
address/mask pairs.
It is mostly a policy definition by the ALTO and infrastructure
operator.
In the current world, peers are partitioned by IP subnet. While
considering virtual machines migration, there might be more
interesting things to think of.
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'. 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). 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.
that is true. ALTO relies on accurate infrastructure/topology
information. It can be derived from lower layers (routing and below)
or inferred by policy DBs.
VMs may migrate under, but not limited to, these situations: 1) to
save electricity power, 2) disaster recovery, 3) customer prefer
another Data Center, 4) company extension, etc. In the end, the
internet will not be a regular world partitioned by IP Addresses.
the "swamp" already validated the theory...
Does anyone think this is an interesting aspect to study?
probably yes but I'm not sure I see the protocol implication.
s.
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