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

Hi Alper,

Thanks for the answer. Please check inline.

On 29-05-2015 22:44, Alper Yegin wrote:

Hello Sergio,

On May 22, 2015, at 6:24 PM, FIGUEIREDO Sergio wrote:



Hi Alper,

As Seil wrote, the problem which this ticket intends to reflect is that of non-optimal routing as a result of not being able to request a non-anchored (or local) source IP address.


A non-anchored (local) address is called Nomadic IP Address.
If the app needs one such address, then it can ask one and get one.
API already supports that.







This might be a problem in any scenario where new Sustained IP addresses are not assigned by default at the new network. The intention of the flag is not to request a new prefix, but to assure a source address associated to a local network is used. Which, in cases where it is not available, leads to the configuration of a new one.



Alper




Best regards,
Sergio


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-----Original Message-----
From: dmm [mailto:[email protected]] On Behalf Of Alper Yegin
Sent: sexta-feira, 22 de Maio de 2015 12:08
To: Seil Jeon
Cc: [email protected]<mailto:[email protected]>
Subject: Re: [DMM] [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]<mailto:[email protected]>      |  [email protected]<mailto:[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><http://trac.tools.ietf.org/wg/dmm/trac/ticket/49>
dmm <http://tools.ietf.org/dmm/><http://tools.ietf.org/dmm/>


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