RE: [DNA] Considerations for DNA Schemes with multipleInterfaceandLayer 2 Technologies

[Brijesh Kumar <kumarb@research.panasonic.com>]

> -----Original Message-----
> From: owner-dna@ecselists.eng.monash.edu.au
> [mailto:owner-dna@ecselists.eng.monash.edu.au]On Behalf Of NJEDJOU Eric
>
> In the same respect,
>  the sentence "Today, a link change necessitates an IP
> configuration change." in the dna goals document introduction let
> the reader believe that a node would not be having interfaces
> attached to other links. Because if it is so, then the a
> configuration that might have been built on the non used link
> could start being used  without requiring new IP configuration.

It makes definite sense to me to clarify this aspect in any document
that is discussing goals/ objective etc.

I think there are three interfacing scenarios:

a) single CDMA interface capable of connecting to two base
stations (APs/BTS+BSS), each base station connected to a
different network.

b) two or more interfaces connected to a single network (same AR)

c) Two or more interfaces on the device, but each interface connected
to a separate network (902.11 + GPRS EDGE combo, or two 802.11
interfaces)


Cheers,

--bk



>
>
> -----Message d'origine-----
> De : owner-dna@ecselists.eng.monash.edu.au
> [mailto:owner-dna@ecselists.eng.monash.edu.au] De la part de
> Pekka Nikander
> Envoyé : lundi 25 octobre 2004 08:59
> À : Dna
> Cc : Erik Nordmark; YGHONG; ???; Greg Daley; JinHyeock Choi; ???
> Objet : Re: [DNA] Considerations for DNA Schemes with multiple
> Interface and Layer 2 Technologies
>
> >> I think that the case 3.2, 'Single interface with Make before Break'
> >> will affect DNA solution design. I agree that we are not familiar
> >> with this case, so it would be of much help, if you elaborate the
> >> below with more detail.
> >>
> >>                 ... But in CDMA[7], a
> >>      mobile station can access two or more different base stations
> >>      simultaneously. In this case, a host can make a new link-layer
> >>      connection before an old link-layer connection is torn down.
> >
> > I hope that L2 can actually tell the packets apart.
> > If this is possible, then the implementation could present the packets
> > from the different links are arriving on different interfaces to IP.
>
> I agree with Erik and others that the apparently cleanest way is
> to model the situation with distinct (virtual) interfaces, each
> corresponding to a wireless connection.
>
> However, I am also wondering how often we need that in practise.
> As far as I've understood (which may be completely wrong), in the
> typical case the CDMA network models the whole base station
> network as a single link, with a single excess router.  OTOH, I
> have no idea whether soft handovers between operators is defined or not.
> If they are, then we probably need some care there.
>
> Taking a slightly wider angle, we can imagine various anomalies
> like someone inadvertedly connecting two (wireline) LAN segments
> together.  That would (temporarily) create a similar situation.
> Hence, I'm afraid that we need to make the DNA scheme(s) robust
> against these kinds of situations.  However, my current opinion
> (subject to change) is that we should not worry too much about
> these kinds of situations, and it would be perfectly OK if it
> takes some more time to system to recover in such a situation.
> In other words, if some hosts unnecessarily run DNA and
> autoconfiguration, that wouldn't be too bad.
>
> Network operators have to live with the limits of technology
> anyway.  If our DNA effort results in a piece of technology that
> has a number of well documented limitations, that is OK, as long
> as the WG agrees on the limitations.
>
> --Pekka
>
>