> -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Masataka Ohta > Sent: mardi 15 juin 2004 06:06 > To: Ignatios Souvatzis > Cc: Jari Arkko; Pascal Thubert (pthubert); IPv6 WG; Pekka Savola; Greg Daley > Subject: Re: WLAN (was Re: IPv6 Host Configuration of Recursive DNS Server) > > Ignatios Souvatzis; > > >>>I think we're straying from the original topic... > >> > >>I think that infrastructure WLAN is point (not all statsions but > >>only the base station) to multipoint one. > > > Radio, yes. Network, no. The base station creates the illusion of a > > broadcast domain. > > And the problem is that the illusion is not the reality. > > Broadcast over the domain is a lot less reliable than unicast.
I'm not sure that the question is whether ND is good or poor, OSPFv3 is good or poor, etc... All these protocols have proven their qualities in the context they were designed for. On the other hand, radios open a new world of problems, some of them specific to the type of radio, which prevents them from being efficiently abstracted as classical broadcast media. The link availability is generally much poorer than classical links (even WAN). The bandwidth is changing rapidly, the error rate is several orders of magnitude worse then usual, the connectivity is at best of the many-to-many type etc... For MIPv6 and DNA, we have a set of problems addressed at 802.21 about the visibility of the various potential peers and the control of the radio by L3. There's a lot of activity around what's being called the radio layer 2.5; Should we change all the upper layer protocols, all the radios, or is there a way to produce an adaptation layer between 2 and 3, which minimizes these changes... and what should the adaptation layer be able to do? Another aspect of this problem is ethernet itself. ND over a broadcast medium is not at its best in terms of performance for DNA related functionalities, such as getting an address. Not arguing we should do PPPoE either since it's still ethernet behind; but saying that the L2 abstraction we take should be as close as possible to the radio operation, in order to minimize the aberrations caused by the emulation, mostly when the emulation is not needed. In many radio cases, the closest abstraction is to be found on serial links. .11 APs are a hub and spoke model, matching some P2MP Frame relay networks. Other radios add a notion of polling and require a stronger flow control, reminding of SDLC. And it would be beneficial for Public AP to be abstracted as PPP in order to reuse all the existing AAA... and to get an address faster, with no DAD (so that's not only DHCP, but also DAD, referring to the discussion between Masataka-san and Greg). Summary is I'm not sure that this discussion is the right angle for the right problem. Sorry about that. It's not even IPv6-over-foo. It's more like what should a new foo-link provide to L3 in order to be more usable than radios are today, and what should it manage by itself in order to get there - at L2.5. Hints about that are already coming from .21 and L2 meshing. Pascal -------------------------------------------------------------------- IETF IPv6 working group mailing list [EMAIL PROTECTED] Administrative Requests: https://www1.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
