Hi, > -----Message d'origine----- > De : [email protected] [mailto:[email protected]] De la part de > jouni korhonen > Envoyé : vendredi 4 novembre 2011 01:22 > À : Jari Arkko > Cc : [email protected] > 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 > > > > _______________________________________________ > > MEXT mailing list > > [email protected] > > https://www.ietf.org/mailman/listinfo/mext > > _______________________________________________ > MEXT mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/mext _______________________________________________ MEXT mailing list [email protected] https://www.ietf.org/mailman/listinfo/mext
