Hi Thomas,

> No. Let's please not go here.

No .. no. My comment is not intended to argue against inventing a new
approach; I'm not in the way. But, if we do not discuss and show a
reasonable technical argument as why an option needs to be ruled out, I
suspect we will end with the exact same answer, but with a different
technology title and functional entities.  I'm more curious to understand
how the VM mobility properties/requirements are any different from IP
mobility requirements of a classical mobile node. In today's deployments,
that classical mobile node is not always a cellular device /laptop, but
can also be a mobile router, IOT device with no user association.


IP Mobility protocols are providing layer-3 mobility to a device. There is
very little relation to the user. If the device moves by itself, or if the
user moves it physically, the protocol has no clue. If there exists any
relation to the user, its only about using the access authentication of
the user and binding that identity to the mobility session. But, even such
user relation is not present in mobile router/IOT deployments. The core
protocol only deals with signaling and managing the forwarding state.
There is no user identity semantic in the data-plane.
 
If a mobile node changes its point of attachment in the network, because
the owner of the device moves it, or when a VM moves across L3 boundaries
due to the administrator triggering a VM migration may not mean any thing
to the protocol underneath. If we take CDMA2000, the MIP stack is in the
chipset and there are many IOT devices with the cellular interface and
there is still IP Mobility for the device without a user operating it.




> the entire physical device is mobile,

This is a good point. But, however you look at it, the "Virtual Machine"
construct is presenting the view of a separate IP node. It has an
Operating System, set of applications, a logical interface card, IP
address configuration, forward stack, and a set of resources. Applications
are able to bind to an address, TCP/UDP ports and are able to send/receive
IP traffic. That Virtual Machine entity as a whole is moving across
networks. Now, why would it matter for layer-3 mobility protocols to be
aware of this subtle difference on a real mobile device, vs a VM instance
? Why is it relevant from the forwarding point of view ?




> Finally, in MIP, the mobile device itself *knows* it is mobile and
>actively participates in that mobility.

There exists two mobility models; Client-based and network-based. For the
later, there is no such assumption on the client awareness. The network is
responsible for providing the mobility.



Regards
Sri




On 10/7/14 9:54 AM, "Thomas Narten" <[email protected]> wrote:

>> =====> Now, if I replace "VM" with "mobile node", that's layer-3
>> mobility and we have few solution options thereŠ
>
>No. Let's please not go here. As David pointed out in a different
>thread, NVO3 is about VM *migration*.
>
>Mobile IP is a very different beast built on a number of fundamentally
>different assumptions. E.g., in mobile IP, the entire physical device
>is mobile, not just a VM. Also, the physical device is moving, i.e.,
>because its owner is carrying it around. In the DC, the VM is moving
>because the DC operator wants to move it. Finally, in MIP, the mobile
>device itself *knows* it is mobile and actively participates in that
>mobility. In data centers, the VMs are oblivious to being moved and
>are not themselves actively involved in any of the signaling or steps
>of the move.
>
>Thomas
>
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