Subject: [Mip6] Minutes of Ad Hoc Meeting on Mobility Architectures for the Internet

From: "James Kempf" <[email-masked]>
Date: Fri, 31 Mar 2006 11:17:05 -0800

Below are some heavily edited minutes from the ad hoc meeting on mobility 
architectures for the Internet that was held in Sapphire on Thurs. at noon. 
If you have any changes, please send them to me. Thanx to Eric Njedjou and 
Alex Petrescu for taking notes.

        jak

--------------------------------------------

These are the minutes of an ad hoc meeting on mobility management 
architectures for the Internet, held on Thurs. of IETF 65 during lunch.

James Kempf started by saying that we discuss mobility architecture for the 
Internet, because we have Mobile IP for some years now, and newly HIP and 
MOBIKE, as host-based global mobility management protocols. Recently NETLMM 
was started to work on a network-based local mobility management protocol 
and now some drafts have been published on network-based global mobility 
management protocols.

Somebody asked: Anybody from MOBIKE here?

James: Well, myself, MOBIKE is done with their spec, through the IESG, in 
the RFC Editor queue for publication.

Pekka Nikander gave a presentation on modelling mobility management 
architecturs. The presentation included UML representations of global 
mobility management, local mobility management and layer 2 mobility 
management.

The information service model needs to have entities working for;
-node identifier
-interface identifier
-point of attachment identifier

IP mobility comes back to tying Node identifiers to interface identifiers.

Discussion:

Kuntal Chowdhury: is IP address tied up with interface identifier of with 
the access router?

Pekka: Network interface is linked to a point of attachment in edge 
mobility, subnet is fixed so that the interface-point of attachment/access 
router link is not dynamic.

Pekka: Talk is really about component and their relationships. In localized 
mobility what is dynamic is the mapping between the network interface/point 
of attachment and home locator

[?]: For any solution, point remains about changing relationship betwen node 
identifier and location identifier?

Pekka: Edge mobility does not care about home address. fixed relationship 
between IP adress, MAC address and network interface.

Ajoy Singh: Depends on deployment, MIP can be used for most of this.

James: Let's concentrate on the architectural level, components and their 
relationship.

Pekka: The most instructive thing here is the "dynamic" part.  Node mobility 
at IP layer or the global layer results in a changing relationship between 
some layer 2 technology id and the CoA. But with edge mobility (NETLMM) you 
don't really care about a HoA anymore,  you just have the CoA.  The dynamic 
mapping is in a different place.

James: It's a really good characterization.

[?]: This works for a single node, but how to characterize multiple nodes, 
interfaces, etc.?

Gopal Dommety: What is the difference between edge and link mobility?

Pekka: I'm still thinking about these issues.

Kent Leung: What do we mean by globally?

Henrik Levkovetz: There are two senses of global, ubiquitous, that is 
available everywhere on all link types, and worldwide, in the sense of 
available at any physical location but possibly only on a particular link 
type. Which do we mean?

Kent: There is need to support the roaming scenario.  But the picture here 
is slighlty different.

James: How an id is mapped into some sort of name, that' s the key issue.
HoA is actually the id for Mobile IP but if HIP then it's not an address, 
it's a HIT. VPN networks use the same mapping as Mobile IP.

Kent: Right. Global mobility for NETLMM is a differnt model from this 
abstraction. For global mobility you have some layer above the id.

Kent: For NETLMM, the issue is inter-MAP handoffs that's where there might 
need to do some work.

James: We discussed this during the BOFs. One way is to use MOBIKE, MIP or 
HIP, another way is to use some kind of network-based, global mobility 
protocol and 3rd way is a handoff protocol from one MAP to another. NETLMM 
may look into this 3rd way, but I'm not convinced it is necessary because we 
have protocols that use the first way.

Vidya Narayanan: Do we see a market for global mobility in the network?

James: The GSM Operators Association has GRX which is basically a 
network-based, global (in the sense of worldwide, not ubiquotous) mobility 
management protocol. The reason it works is because the GSM Operators 
Association negoiates the necessary business agreements between themselves 
for it to work.

James: But the Internet isn't like that.  Dave Clark in his talk last night 
at the social talked about how in 1992, they didn't have a clear sense of 
how the business model for the Internet would evolve. What did evolve was a 
is a very diverse set of businesses, quite unlike the tight knight group of 
integrated operators like the GSM Operators Associatin. Somes ISPs have just 
a few customers. Others, like Sprint, have millions. My personal view is 
that network based global mobility will only work when you have a tight 
group of operators who can negotiate the right business agreements.

Ajoy: Yes there is a market for global mobility, the iDen and CDMA have 
deployed versions.

Aaron Silverton: I was involved in the deploymet of iden it's not Proxy 
Mobile IP. CDMA does use a kind of Proxy Mobile IP.

Eric Njedjou gave a presentation on his draft, "Network Global Mobility 
Management Problem Statement", draft-njedjou-netlmm-globalmm-ps-00.txt.

Eric: We see operators moving to IP services, the question is how to handle 
sessions continuously. Intra-system mobility handled by the current set of 
IP mobility protocols for session continuity. In IETF IP session continuity 
and mobility management happen to have the same definition.  MIP HIP are 
global mobility management solutions for session continuity.

Eric: But in cellular, there is a different perspective on IP mobility. We'd 
like to have inter-system mobility between cellular and WiFi/WiMax, to 
provide service mobility between these. The reason is to support the most 
efficient use of spectrum and other network resources, and to be able to 
guarantee service. These motivations don't put so many requirements on the 
host, the requirement is more on the network where the state of resources 
are known and the complexities of managing them can be more easily dealt 
with.

Eric: The kinds of deployments I'm talking about involve integrated 
WiMax/WiFi/3G networks, and these have different mobility management needs.

Eric: The issues with existing host-based global mobility management are: 
over the air signallig, complexity of mobility procedures.

Eric: Radio cell capacity is a very big problem, having the ability to 
manage mobility in the network between link types would help.

Eric: The problem is there are complex existing solutions such as 
MIP+802.21, MIP+3GPP. These are not scalable to large integrated networks.

Eric: For example, if you handover from one link type to another, you are 
really handing over from one complete signalling and access network type to 
another, and this can be very lengthy. It could take quite a while until the 
home agent responds.

Eric:  The network guarantess a particular service level to the user by 
giving the terminal the best target access link type, considering the 
current level of traffic in the network, radio conditions, etc.  A problem 
here is that MIP will basically be implemented by several manufacturers, and 
for differen SDOs, so there's different handovers and no inter-operability.

Eric: The appendix of our draft describes 3GPP SAE Progress.  We believe it 
won't be scalable. Please read the draft.

Discussion:

Henrik: All the technical points are valid. I see the problem, you presented 
a bit one-sided, based on what the operator wants.  But another side is as a 
user wants to choose the operator.

Henrik: I also had a different impressio of the draft. It is more about 
"comprehensive mobility management", not about "global mobility management". 
It is about managing diverse ressources.

Vidya: It is global in the sense that you consider all types networks, not 
just 3GPP.

Eric: The draft tries not to have a specific solution, but rather state the 
problem and set up a framework.

Vijay: IETF can't deliver on "framework" but on "protocol".

Eric: Yes.

Vijay: I don't know what "framework" means.

Eric: The framework is the IETF scoped framework, both the need of where the 
user wants to move.  I pointed 3 items we need to remove signaling, we route 
optimization, and we need to switch IP interfaces.

Katsutoshi Nishida: So is this a proposal to combine solution mobility 
managenent and QOS?  GTP provides mobility management.  Seems same kind of 
thing we are discussing here.

Eric:  That's better discussed in 3GPP.  We just don't want to have two 
complex
architectures.

Due to time constrants Kuntal was not able to present his proposed solution, 
Poxy MIP6, for network based global mobility management; however, he showed 
an architecture slide and the group discussed its relevance to the problem. 
The protocol is described in draft-chowdhury-netmip6-00.txt.

Vidya: The applicabiliy of the draft looks not clear. Is it applicable to 
NETLMM or MIP6 or something different?

Kuntal: NETLMM looks like it is solving the need to manage the change 
between the AR and MAP

[?]: The MAP is not an HA. But it could be.

Vijay: If the NETLMM domain is large enough, some part of the global 
mobility problem is solved.

[?]: Global mobility problem looks more of an adminsitrative issue.

Kuntal: Are you saying NETLMM is trying to solve the mobility problem in 
global sense?

[?]: Proxy-MIP could be NETLMM. The design team is still discussing what the 
best NETLMM solution is.

James: How is this different from MIP4? Aren't you just putting a FA on the 
AR Except there is no MIP signaling between the client and network?

Kuntal: The signaling between the client and network is PPP in this case.

Vidya: Do you seee serving AR and HA as belonging to different admin domain?

Kuntal: Yes.

Vidya: Then how do you see them establishing a security association?

James: During the NETLMM BOFs, we were told by an IAB member that unless the 
security issues of Proxy MIP are solved, any document produced by the WG 
will be quickly be returned back to the WG.

The group then discussed next steps.

James: Should we start a mailing list, try to organize a BOF?

Vijay/Henrik: Where is the need for a BOF now?

[?]: Looks like some agreement that Eric's draft raises some problems 
currently uncovered by the IETF protocols.

[?]: Perhaps we need to separate the issues raised by Eric's draft from 
other issues?

James: Need to discuss with MIP6 chairs wether they would like to address 
the issue in draft-chowdhury-netmip6-00.txt in MIP6 working Group.

Gopal: Not clear whether Kuntal problem is in the MIP6 working group. Two 
questions are to be answered. Why Proxy-MIP is needed and why is not needed.

Stefano Faccin: 802.21 and the MIPSHOP WG are trying to address some of the 
issues in Eric's draft.

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