Re: [dmm] #49 (ondemand-mobility): full on-demand mobility support

Hi Seil,

Thanks for creating the ticket.

Please see below.


> 
> #49: full on-demand mobility support
> 
> The three proposed flags express a “type” of source IP address an  application wants to get to the IP stack. Particularly, the sustained IP  address is proposed to provide on-demand IP session continuity, which  activates IP mobility once the terminal moves across other access network.
> While the terminal stays at the same network where the session is  initiated, regular IP routing is applied.
> 
> The on-demand draft does not assure provide the full on-demand mobility  for all scenarios by merely indicating the Socket API,  IPV6_REQ_SUSTAINED_IP. An example scenario raising the aforementioned  issue is as follows;
> 
> 0. The MN is configured with one or more Nomadic IP addresses.
> 
> 1. Once an app. requests “sustained IP address” to the IP stack, and it  will obtain a sustained IP address through a protocol procedure between  the terminal and network.
> 
> 2. Other app. initiated over the same access network will use the same  sustained IP address while the terminal remains connected at the same  access network.
> 
> 3. The terminal moves to another access network and a new app. requests a  sustained IP address with the Socket API to the IP stack. Since a  sustained IP address is already available in the IP stack, the sustained  IP address is assigned to the new app.
> 

Yes, that's what happens.
You are not pointing to an issue up until this point, right? Because, you continuing your email with a "Besides" gives the impression that you are pointing to an issue, but I don't see any issue captured in the above text.


> Besides, in case sustained IP address allocation is used default, there  may be multiple sustained IP addresses including newly obtained sustained  IP address over the new access network in the IP stack. However, when an  app. is initiated, the IP stack may not select the new one in the context  of the default source IP address selection mechanism [RFC6724][RFC5014].
> 

OK, is the issue following: When there are multiple sustained IP addresses, how does the IP stack pick one among them?

> For providing the full on-demand mobility, a new flag is needed, letting  the IP stack request a new sustained IP address or choose a sustained IP  address not requiring IP mobility anchoring when an application is  initiated, among the existing ones in the IP stack.
> 

Your flag is not a solution to what I captured above. It does something else: Instruct the IP stack to go get a new sustained IP address whether there is already one or more configured on the stack or not.


Alper



> -- 
> -------------------------+----------------------------------------------
> -------------------------+---
> Reporter:               |      Owner:  draft-ietf-dmm-ondemand-
>  [email protected]      |  [email protected]
>     Type:  defect       |     Status:  new
> Priority:  critical     |  Milestone:
> Component:  ondemand-    |    Version:
>  mobility               |   Keywords:  on-demand mobility
> Severity:  Submitted    |
>  WG Document            |
> -------------------------+----------------------------------------------
> -------------------------+---
> 
> Ticket URL: <http://trac.tools.ietf.org/wg/dmm/trac/ticket/49>
> dmm <http://tools.ietf.org/dmm/>
> 
> 
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