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
> 
> 
> 2, rue Paul Vaillant-Couturier
> 92300 Levallois-Perret 
> FRANCE
> Tel. : +33 (0)1 46 17 46 17
> -----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]
> 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]      |  [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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> 
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