Re: [MEXT] the future of the MEXT working group

[<[e-mail]>]

Hi,

> -----Message d'origine-----
> De : [e-mail] [mailto:[e-mail]] De la part de
> jouni korhonen
> Envoyé : vendredi 4 novembre 2011 01:22
> À : Jari Arkko
> Cc : [e-mail]
> Objet : Re: [MEXT] the future of the MEXT working group
> 
> 
> Hi,
> 
> Few quick comments. I would remove all explicit references to 3GPP and
> existing offload mechanisms therein. FWIW this WG is not supposed to be a
> stub of SA2. The possible (protocol) enhancement must be generic enough to
> be applicable outside of a specific deployment architecture.
> 

I definitely agree to remove reference to 3GPP. However, I think we need clear use-case to motivate the distribution. As a starting point, we could assume a network architecture relying on the distribution of traffic anchors for local IP access/CDN; then study how to bring mobility support in this context. 

> Also, I think we ought not only consider just mobility enhancement. More
> efficient use of CoA(s) for direct/local/non-tunneled communication along
> with existing mobility solutions should be in scope as well.
> 

Actually, this is the idea behind dynamic mobility management described in the charter: use the CoA for IP flow which does not require mobility support. We are inline.

Pierrick

> - Jouni
> 
> On Oct 28, 2011, at 3:21 PM, Jari Arkko wrote:
> 
> > And a follow-up on the charter. I'm describing a couple of different
> takes on what the new charter could be. Comments and alternative proposals
> are welcome. This is what the current charter says about DMM:
> >
> >>   The working group will also work on operational considerations on
> >>   setting up Mobile IPv6 networks so that traffic is distributed
> >>   in an optimal way, for instance by using existing protocol mechanisms
> >>   to select the closest home agents for new clients.
> >>
> >>   Oct 2011 - Submit I-D 'Operational considerations for distributed use
> of Mobile IPv6' for publication as Informational.
> >
> > Which is admittedly a bit short, but is also very concrete and
> achievable, if we work on it. I got another proposal from Hui Deng that
> extended this a bit, including going beyond mere operational
> considerations.
> >
> >> In the past decade a fair number of mobility protocols have been
> standardized. Although the protocols differ in terms of functions and
> associated message format, we can identify a few key common features:
> >> presence of a centralized mobility anchor providing global reachability
> and an always-on experience
> >> extensions to optimize handover performance while users roam across
> wireless cells
> >> extensions to enable the use of heterogeneous wireless interfaces for
> multi-mode terminals (e.g. cellular phones)
> >> The presence of the centralized mobility anchor allows a mobile device
> to be reachable when it is not connected to its home domain. The anchor,
> among other tasks, ensures forwarding of packets destined to or sent from
> the mobile device. As such, most of the deployed architectures today have
> a small number of centralized anchors managing the traffic of millions of
> mobile subscribers.
> >>
> >> To optimize handovers for mobile users, the base protocols have been
> extended to efficiently handle packet forwarding between the previous and
> new points of attachment. These extensions are necessary when applications
> impose stringent requirements in terms of delay. Notions of localization
> and distribution of local agents have been introduced to reduce signalling
> overhead. Unfortunately today we witness difficulties in getting such
> protocols deployed, often leading to sub-optimal choices. Moreover, all
> the availability of multi-mode devices and the possibility to use several
> network interfaces simultaneously have motivated the development of more
> new protocol extensions.
> >>
> >> Mobile users are, more than ever, consuming Internet content, and
> impose new requirements on mobile core networks for data traffic delivery.
> When this traffic demand exceeds available capacity, service providers
> need to implement new strategies such as selective traffic offload (e.g.
> 3GPP work items LIPA/SIPTO) through alternative access networks (e.g.
> WLAN). Moreover, the localization of content providers closer to the
> Mobile/Fixed Internet Service Providers network requires taking into
> account local Content Delivery Networks (CDNs) while providing mobility
> services.
> >>
> >> As long as demand exceeds capacity, both offloading and CDN techniques
> could benefit from the development of more flat mobile architectures (i.e.,
> fewer levels of routing hierarchy introduced into the data path by the
> mobility management system). This view is reinforced by the shift in
> users' traffic behaviour, aimed at increasing direct communications among
> peers in the same geographical area. The development of truly flat mobile
> architectures would result in anchoring the traffic closer to point of
> attachment of the user and overcoming the suboptimal routing issues of a
> centralized mobility scheme.
> >>
> >> While deploying today's mobile networks, service providers face new
> challenges. More often than not, mobile devices remain attached to the
> same point of attachment, in which case specific IP mobility management
> support is not required for applications that launch and complete while
> connected to the same point of attachment. However, the mobility support
> has been designed to be always on and to maintain the context for each
> mobile subscriber as long as they are connected to the network. This can
> result in a waste of resources and ever-increasing costs for the service
> provider. Infrequent mobility and intelligence of many applications
> suggest that mobility can be provided dynamically, thus simplifying the
> context maintained in the different nodes of the mobile network.
> >>
> >> The proposed charter will address two complementary aspects of mobility
> management procedures: the distribution of mobility anchors to achieve a
> more flat design and the dynamic activation/deactivation of mobility
> protocol support as an enabler to distributed mobility management. The
> former has the goal of positioning mobility anchors (HA, LMA) closer to
> the user; ideally, these mobility anchors could be collocated with the
> first hop router. The latter, facilitated by the distribution of mobility
> anchors, aims at identifying when mobility must be activated and
> identifying sessions that do not impose mobility management -- thus
> reducing the amount of state information to be maintained in the various
> mobility anchors of the mobile network. The key idea is that dynamic
> mobility management relaxes some constraints while also repositioning
> mobility anchors; it avoids the establishment of non optimal tunnels
> between two anchors topologically distant.
> >>
> >> Considering the above, the working group will:
> >>
> >> Define the problem statement and associated requirements for
> distributed mobility management. This work aims at defining the problem
> space and identifies the key functional requirements.
> >>
> >> Produce a gap analysis mapping the above requirements against existing
> solutions.
> >>
> >> Give best practices for the deployment of existing mobility protocols
> in a distributed mobility management and describe limitations of each such
> approach.
> >>
> >> Describe extensions, if needed, to current mobility protocols for their
> application in distributed mobility architectures
> >
> > Comments?
> >
> > Jari
> >
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