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

[liu dapeng <[e-mail]>]

Hi Pierrick,



2011/11/2, [e-mail] <[e-mail]>:
> Hi Jari,
>
>
>
> Just a minor comment:
>
>
>
> This charter addresses both the distribution of mobility functions and the
> dynamic mobility management. Even if dynamic activation/deactivation of
> mobility support can be seen as an enabler to distributed mobility
> management, I think the work item acronym should refer to both features. So,
> to avoid any ambiguity, I'd suggest to use the acronym DDMM (Distributed and
> Dynamic Mobility Management) for the work item.

There is no contradiction between distributed and dynamic. Actually
"dynamic mobility" could be considered as some sort of  "distributed
mobility". So I think DMM is a simple and concise acronym.

Dapeng

>
>
> Regards,
>
> Pierrick
>
>
>
>
>
> ________________________________
>
> De : [e-mail] [mailto:[e-mail]] De la part de Jari
> Arkko
> Envoyé : vendredi 28 octobre 2011 14:21
> À : [e-mail]
> Objet : Re: [MEXT] the future of the MEXT working group
>
>
>
> 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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Best Regards,
Dapeng Liu