On Fri, 2012-01-13 at 12:34 +0100, Aleksander Morgado wrote: > Hey Marcel, > > > > >>>> I believe we need a MMBearerType enum in the 0.6 API, so that we can > >>>> tell in CreateBearer() whether we want a 3GPP or CDMA (well, or POTS) > >>>> bearer. This property would be redundant for 3GPP-only, CDMA-only or > >>>> POTS-only modems, but would be mandatory if we have a mixed > >>>> 3GPP(LTE)+CDMA bearer. This value would also be shown as a property in > >>>> the Bearer interface, so that we can know the type of the bearer behind > >>>> a given DBus path. Another possibility to avoid the new enum would be to > >>>> assume that if "apn" is given when creating the bearer, we want a 3GPP > >>>> bearer, while if no "apn" is given we really want a CDMA bearer. But not > >>>> sure I like to rely just on this "apn"-based logic. What do others think? > >>> > >>> The problem with that approach is handoffs. If you create a 3GPP/LTE > >>> bearer and then leave LTE coverage where the device hands off to EVDO, > >>> now your 3GPP bearer is a CDMA bearer. In this scenario there's no > >>> interruption of packet data service and you don't even know anything > >>> happened except that the access technology changed from LTE to EVDO. > >> > >> Well, that is already some indication that we can use. If we had a 3GPP > >> bearer connected, and suddenly the access technology changed to EV-DO, > >> then we could internally mark the CDMA bearer as connected and mark the > >> 3GPP one as disconnected. If done in that order, we wouldn't be issuing > >> any state change notification. This, assuming that for mixed technology > >> modems we have different technology-specific bearers. The only drawback > >> of having technology-specific bearers is that for the user not using the > >> Simple interface, it would mean needing to create two bearers with two > >> CreateBearer() calls. But I don't think that that is a big deal; if the > >> user of a mixed CDMA+LTE modem just creates a 3GPP bearer and gets it > >> connected, and then we detect the connection handed off to CDMA, we can > >> request the disconnection of the bearer and that's it. If the user > >> didn't create a CDMA bearer, we would need to assume she didn't want a > >> CDMA connection. If using the Simple interface, all that would be > >> automatic, different bearers would be created automatically. > > > > there is no guarantee that the IP connection details stay the same. > > There is no IP connection detail stored in the ModemManager bearers, so > that wouldn't be a big deal for us I guess. Maybe I'm missing something.
Except for Static mode :) > > > > Before everybody goes crazy here you might wanna check if Verizon even > > provides the same IP address when falling back to CDMA from LTE. > > > > They probably don't give the same IP address, so if the hand off is > really transparent (i.e. not getting disconnected and then connected > again), I assume we rely on the modem itself to detect that and handle > the IP switch at PPP session level. I cannot really do any such test, so > cannot tell :-/ Again, I'm still trying to find out, but I think there are cases where we may get the same IPv4 and IPv6 address. Dan _______________________________________________ networkmanager-list mailing list [email protected] http://mail.gnome.org/mailman/listinfo/networkmanager-list
