Hi Pierrick,
2011/11/2, [email protected] <[email protected]>: > 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 : [email protected] [mailto:[email protected]] De la part de Jari > Arkko > Envoyé : vendredi 28 octobre 2011 14:21 > À : [email protected] > 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 > > -- ------ Best Regards, Dapeng Liu _______________________________________________ MEXT mailing list [email protected] https://www.ietf.org/mailman/listinfo/mext
