Re: AD Evaluation: draft-ietf-dmm-requirements

The reason for this requirement is that in some existing mobility management deployment, in order to support those applications that does need network-layer mobility support, the mobile host uses HoA so that all the applications must use the HoA. Then it does not make it possible for an application to not use HoA.  

So the bottom line in this revision is that the DMM solution only allows the possibility of not using the network-layer mobility support. 

How to make use of this possibility is now not a part of this requirement. Therefore the requirement should avoid implication of such mechanisms.

When we called "when needed", there may be implication of a mechanism to determine/convey the need.

When we call it "invoke", there may be implication of a mechanism to invoke.

Let me try the following:

    REQ2:  Bypassable Network-layer mobility support
  
           DMM solutions MUST enable network-layer mobility
           but it MUST be possible to bypass it.

           (plus other sentences on the need and the no need to serve as explanations only to justify the above)

H Anthony Chan


-----Original Message-----
From: Brian Haberman [mailto:[email protected]] 
Sent: Thursday, January 30, 2014 8:02 AM
To: h chan; [email protected]
Subject: Re: [DMM] AD Evaluation: draft-ietf-dmm-requirements

Hi Anthony,

On 1/29/14 1:51 PM, h chan wrote:
> Brian,
> 
> The requirement is intended to include a capability of not using 
> network-layer mobility management, as opposed to using it by default.
> 
> 
> I think it is sufficient to leave to the explanation (the sentences 
> after the first sentence) to say that network-layer mobility support 
> is not always needed in order to justify this capability.
> 
> The alternative then is to say that network-layer mobility is provided 
> but it is possible to not use such support.
> 
> REQ2:  Using and not Using Network-layer mobility support
> 
> DMM solutions MUST enable network-layer mobility but it MUST be 
> possible to not invoke it. Mobility support is needed, for example, 
> when an application or a host cannot cope with a change in the IP 
> address when a node moves. Yet a mobile node can often be stationary, 
> and mobility support can also be provided at other layers. It is then 
> not always necessary to maintain a stable IP address or prefix.
> 
> Of cause "enable" does not mean it must be used. Yet explicitly say 
> "it is possible to not invoke it" is to draw the contrast to using it 
> by default.

My only concern is that it is unclear *who* invokes the network-layer mobility support.  Is it envisioned that the application can signal the need for mobility support?  Does the user have to configure which applications get support?

Regards,
Brian