RE: [Seamoby] Minutes for Meeting at IETF 53

["Govind Krishnamurthi" <[e-mail]>]

Hello Karim,

>Since a couple of emails disagreed with me about this point,
>I'm sending one email reply to clarify. As in the minutes,
>the concept was that the only entity which can find out
>all the possible CARs is the MN (that's what I mean by mobile-centric).

[Govind] Sure, but there may be inherent constraints. Suppose there is
just one interface, and the MN can hear multiple L2 beacons and
if figuring out which ARs these L2 devices  are connected
to implies that the
MN has to disconnect from the current AP then what good is
the MN finding out the GAARs in this case. Also, to know CARs the
MN has to get the capabilties (whatever they might be) from each
and every GAAR. This may  be an expensive proposition in terms of
wireless bandwidth.

>The network could give hints, but it is the MN that has the complete
>view and decides. That's what I understood from the meeting and there
>seemed to be consensus on this. Hope we agree so far. The network
>could assist in CAR discovery (e.g. it's L2 can help in anticipating
>the movement). That's also somewhere in the minutes. In fact what I
>said below was that I couldn't understand why there was focus on a
>network-centric solution (i.e. where the MN is NOT involved).

[Govind] I don't know where you saw a network based solution which
completely prohibits the MN from participation. CAR discovery by
definition needs the capability match of the ARs with the MN's requirements. 
So there cannot be a case wherein the MN is not
involved.

I wasn't
>ruling out network involvement, but I couldn't understand why there
>was work on ARs only doing CAR discovery. Hope my point is more clear
>now. Maybe I misinterpreted some emails and people are in agreement
>with this. I think Dirk's email at least was in line with what I
>have above (i.e. we need to focus on the MN's role and allow the
>network to assist where needed).

[Govind] The main point is that the MNs requirements should be
taken into consideration when deciding on the TARs whether this
happens in the network or in the MN is upto the individual solution
(as long as it satisfies the requirements).
Hope these clarifies your concerns.

Regards,
Govind.

>Rgds
>/Karim
>
>  > -----Original Message-----
>  > From: Govind Krishnamurthi [mailto:[e-mail]]
>  > Sent: den 17 april 2002 21:22
>  > To: [e-mail]; [e-mail];
>  > [e-mail]; [e-mail]
>  > Subject: RE: [Seamoby] Minutes for Meeting at IETF 53
>  >
>  >
>  >
>  >
>  >
>  > Hello Karim,
>  > First, I don't think that Steve Deering said anything about excluding
>  > the network from CAR discovery. All he said (AFAIK) was that the MN's
>  > preferences must be satisfied in the decision of selecting the TAR.
>  > Now that doesn't imply MN based CAR discovery: that the MN
>  > should receive
>  > all the capabilities and GAAR IDs and then make the decision.
>  >
>  >
>  > Regards,
>  > Govind.
>  >
>  > >
>  > >The reason I sent my previous email was that I got the feeling
>  > >from this thread that there is focus on providing a solution for
>  > >the network-centric case (i.e. the network handles CAR discovery
>  > >and the MN isn't involved). I wanted to point out that this
>  > >solution would not be applicable to the mobile-centric case and
>  > >clarify that this case is supported by MIP (v4 and v6) fast
>  > >handoffs.
>  > >
>  > >From the IETF meeting there was a majority who wanted to go for
>  > >the mobile-centric case (i.e. where the mobile is involved and
>  > >decides). Following Steve's presentation I think that became
>  > >quite clear. So, why are there discussions about doing a solution
>  > >which is meant for the network-centric case only? This solution
>  > >wouldn't apply to the mobile-centric case. That's what I was meant
>  > >to ask in my last email.
>  > >
>  > >/Karim
>  > >
>  > >  > Karim,
>  > >  >
>  > >  > But it is applicable to network initiated handoff. And
>  > there are two
>  > >  > algorithms, one in which the access router sends a PrxyRtAdv
>  > >  > to the MN
>  > >  > and one in which the MN is switched (for FMIPv4).
>  > >  >
>  > >  >             jak
>  > >  >
>  > >  > ----- Original Message -----
>  > >  > From: "Karim El-Malki (ERA)" <[e-mail]>
>  > >  > To: "'James Kempf'" <[e-mail]>; "Hemant Chaskar"
>  > >  > <[e-mail]>; <[e-mail]>
>  > >  > Sent: Tuesday, April 16, 2002 11:55 AM
>  > >  > Subject: RE: [Seamoby] Minutes for Meeting at IETF 53
>  > >  >
>  > >  >
>  > >  > > > > >[The Issue]
>  > >  > >  > > >It seems that the minutes indicate that people have
>  > >  > >  > somehow come to a
>  > >  > >  > > >conclusion that there is no need for access routers to
>  > >  > >  > divulge that
>  > >  > >  > they
>  > >  > >  > > >are
>  > >  > >  > > >geographically adjancent to themselves via the IP
>  > >  > >  > infrastructure. The
>  > >  > >  > > >minutes also seem to indicate that the mobile
>  > alone should be
>  > >  > the
>  > >  > >  > only way
>  > >  > >  > > >to pass addresses of CARs to source ARs.
>  > >  > >  > > >
>  > >  > >  > > >[Technical Questions]
>  > >  > >  > > >O.K. If this is true then how will a mobile pass this
>  > >  > >  > information to
>  > >  > >  > their
>  > >  > >  > > >source AR if the mobile only has one NIC and that NIC is
>  > >  > >  > only capable
>  > >  > >  > of
>  > >  > >  > > >listening to one media at once?
>  > >  > >  > >
>  > >  > >  > > [HC] I agree that this is a genuine technical
>  > problem. What I
>  > >  > would
>  > >  > >  > really
>  > >  > >  > > like to understand is whether the above is a
>  > relevant case for
>  > >  > CAR
>  > >  > >  > discovery
>  > >  > >  > > or we simply neglect it and focus only on two
>  > >  > physical interfaces
>  > >  > >  > case. I
>  > >  > >  > > raised this question before, but we have not had much
>  > >  > discussion
>  > >  > on
>  > >  > >  > it. In
>  > >  > >  > > any case, address translation part of CARD will
>  > be required in
>  > >  > this
>  > >  > >  > case for
>  > >  > >  > > fast handoff support.
>  > >  > >  > >
>  > >  > >  >
>  > >  > >  > In a single interface handoff situation, Layer 2 typically
>  > >  > >  > delivers the
>  > >  > >  > AP or AR L2 identifier to which the MN will be
>  > handed over. This
>  > >  > >  > information is required (by the MIP fast handover
>  > algorithms) at
>  > >  > the
>  > >  > >  > MN's AR. So the issue is fairly simple: the AR must be
>  > >  > able to do
>  > >  > >  > reverse address translation in order that it can
>  > contact the
>  > >  > >  > other AR.
>  > >  > >
>  > >  > > This is not really applicable to Mobile-Initiated MIP
>  > Fast Handoff.
>  > >  > > In Mobile-initiated we consider the useful case where
>  > the MN can
>  > >  > recover
>  > >  > > the CAR IP address/es from the L2 trigger. The MN then
>  > >  > sends a Proxy
>  > >  > > Router Solicitation (RtSolPr) to its curent AR containing
>  > >  > one or more
>  > >  > CAR
>  > >  > > IP addresses. This means that the source AR already
>  > gets the CAR
>  > >  > addresses.
>  > >  > > So we can do without the AR doing translation or discovering
>  > >  > geographical
>  > >  > > adjacency. The MN can pass these CAR address/es to the
>  > >  > source AR for
>  > >  > both
>  > >  > > single and multiple-interface MNs. So I think that the
>  > >  > conclusion from
>  > >  > the
>  > >  > > meeting is compatible with MIP Fast Handoffs.
>  > >  > >
>  > >  > > /Karim
>  > >  > >
>  > >  >
>  > >
>  > >_______________________________________________
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