Subject: RE: [Seamoby] Minutes for Meeting at IETF 53

From: "Hemant Chaskar" <[email-masked]>
Date: Wed, 17 Apr 2002 14:56:31

Hi Karim:

>From: "Karim El-Malki (ERA)" <[email-masked]>
>To: "'Hemant Chaskar'" <[email-masked]>, [email-masked],   
>[email-masked]
>Subject: RE: [Seamoby] Minutes for Meeting at IETF 53
>Date: Wed, 17 Apr 2002 12:13:57 +0200
>
>  > >  > 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
>  >
>  > [HC] I am wondering, if this useful case is genral enough.
>  > In other words,
>  > can MN always get IP addresses from AP beacons (or L2
>  > triggers) without
>  > having to acquire connectivity with AP. More so, in single NIC case.
>
>[KEM] If you get a trigger at the MN you are somehow told
>that you have to move and this could contain the network's desired
>place where you should move (if it's multi-technology then one network
>may not know all that is possible). Here it is assumed that these are
>IP addresses or that the IP addresses can be easily recovered. The MN
>collects the full list of CAR addresses and decides. At least that's
>what I understood people wanted at the last meeting. Do you think it
>is not generic enough since it relies on IP addresses recovered from
>triggers?

[HC]I think the issue was raised about single NIC case. So, if you are 
saying that in general single NIC case, IP addresses will always be 
available in beacons (L2 triggers), then our problem becomes simpler, that 
is great. I am still looking for answer to question: Is capability discovery 
required in this case and how to do this? When you receive multiple L2 
becons (and hence multiple IP addresses from those beacons from L2 triggers 
that you have in mind), which one to choose still remains a question. Or, 
will L2 triggers also include capability set of ARs?

Also, another issue that was raised for both single and multiple NIC case 
was about power and bandwidth considerations in receiving capabilities at 
MN. Again, if that is not a concern then our problem becomes simpler.

>
>  >
>  > Also, could you please say what conclusion you are referring to.
>
>[KEM] I'm referring to the discussion about mobile-centric vs 
>network-centric
>approaches related to Steve's presentation. I believe there was a
>consensus on mobile-centric, which favours a CAR discovery solution where 
>the
>MN is involved and takes the decisions.
>
>/Karim

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From: "James Kempf" <[email-masked]>
Date: Thu, 18 Apr 2002 11:23:59 -0700

I don't think one can assume that IP addresses are available in L2
triggers in the general case. But it must still be possible to map an L2
identifier for an AP/AR to an IP address.

I think there is one class of problem involving L2 handover where power
is the only criterium in which capabilities are not of interest and
handover is controlled at L2. That's how it is done today. There is
another class where L3 had some input, especially for the
intertechnology case but also potentially for intratechnology where time
is not of the essence and potentially also for a future L2 where IP
makes most of the decisions. In this case, capabilities are of interest.

My 0.02 euro.

            jak

---

From: "James Kempf" <[email-masked]>
Date: Thu, 18 Apr 2002 11:23:59 -0700

My 0.02 euro.

            jak