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

From: "Karim El-Malki (ERA)" <[email-masked]>
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?

 > 
 > 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: "Eunsoo Shim" <[email-masked]>
Date: Wed, 17 Apr 2002 20:27:13 -0700

Hi, Karim,

What kind of L2 triggers provide the IP address(es) of the target
(candidate) access routers?
Would you mind providing some examples?
Thanks.

Eunsoo
----- Original Message -----
From: "Karim El-Malki (ERA)" <[email-masked]>
To: "'Hemant Chaskar'" <[email-masked]>; <[email-masked]>;
<[email-masked]>
Sent: Wednesday, April 17, 2002 3:13 AM
Subject: RE: [Seamoby] Minutes for Meeting at IETF 53

---

From: "Eunsoo Shim" <[email-masked]>
Date: Wed, 17 Apr 2002 20:27:13 -0700

Hi, Karim,

Eunsoo
----- Original Message -----
From: "Karim El-Malki (ERA)" <[email-masked]>
To: "'Hemant Chaskar'" <[email-masked]>; <[email-masked]>;
<[email-masked]>

---

From: Behcet Sarikaya <[email-masked]>
Date: Wed, 17 Apr 2002 16:09:43 -0500

>(candidate) access routers?
http://ietf.org/internet-drafts/draft-ietf-mobileip-lowlatency-handoffs-v4-03.txt
states that the triggers L2-MT and L2-ST and L2-LU have nFA IP address 
as parameters.
Hope this helps.

--behcet

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From: Behcet Sarikaya <[email-masked]>
Date: Wed, 17 Apr 2002 16:09:43 -0500

--behcet

---

From: "Eunsoo Shim" <[email-masked]>
Date: Thu, 18 Apr 2002 14:12:54 -0700

Hi, Behcet,

Thanks for the information.
My understanding is that the low latency handoff proposal ASSUMES or
REQUIRES that such L2 triggers are available. Then the question would be how
such L2 triggers containing the IP address of the nFA could be generated. I
don't think we have a general solution for the problem yet. So I don't think
we can say "Look! we have L2 triggers that provide the IP address of the
target access router." yet.

I understand the need to design a way to get L2 ID to IP address mapping was
one of the major motivations for the CAR discovery protocol while we know
that the MN can get the L2 ID of the new base station from the L2 beacons.
Actually the CAR discovery protocol could be used to construct the L2
trigger message required/assumed in the draft.

Regards,

Eunsoo
----- Original Message -----
From: "Behcet Sarikaya" <[email-masked]>
To: <[email-masked]>
Sent: Wednesday, April 17, 2002 2:09 PM
Subject: Re: [Seamoby] Minutes for Meeting at IETF 53

> >(candidate) access routers?
http://ietf.org/internet-drafts/draft-ietf-mobileip-lowlatency-handoffs-v4-0
3.txt

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From: "Eunsoo Shim" <[email-masked]>
Date: Thu, 18 Apr 2002 14:12:54 -0700

Hi, Behcet,

Regards,

Eunsoo

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From: "James Kempf" <[email-masked]>
Date: Thu, 18 Apr 2002 08:08:31 -0700

> Would you mind providing some examples?

There are no specific examples today of commerial link layers that do
this, but we have done some experiments involving modifying the IS-2000
RAN to support triggers. It works extremely well.

Also, it's possible to generate a "trigger" of sorts by forcing handoff
on certain 802.11 cards that provide to application software the BSSids
for access points the mobile can hear. The mobile can utilize the BSSid
to find the FA or AR address, or it can send it to the AR to find the
address.

            jak

---

From: "James Kempf" <[email-masked]>
Date: Thu, 18 Apr 2002 08:08:31 -0700

jak

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From: "Eunsoo Shim" <[email-masked]>
Date: Sun, 21 Apr 2002 13:06:46 -0700

James,

Could you tell us, if possible, how the IP address of the target address is
discovered in your experiment with the IS-2000 RAN?
Also how can the mobile utilize the BSSid to find the FA or AR address
without asking the current AR in 802.11? Don't we need something like the
CAR discovery protocol eventually? I assume the mobile does not receive the
Agent Advertisement messages of the target AR in the above question.
Regards,

Eunsoo

----- Original Message -----
From: "James Kempf" <[email-masked]>
To: "Eunsoo Shim" <[email-masked]>; "Karim El-Malki (ERA)"
<[email-masked]>; "'Hemant Chaskar'" <[email-masked]>;
<[email-masked]>
Sent: Thursday, April 18, 2002 8:08 AM
Subject: Re: [Seamoby] Minutes for Meeting at IETF 53

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From: "Eunsoo Shim" <[email-masked]>
Date: Sun, 21 Apr 2002 13:06:46 -0700

James,

Eunsoo

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From: "James Kempf" <[email-masked]>
Date: Sun, 21 Apr 2002 02:43:56 -0700

> discovered in your experiment with the IS-2000 RAN?

The work on the IS-2000 RAN was done by Motorola, Ajoy Singh was the
technical lead. I've cc'ed him on this response, perhaps he can describe
how the L2 triggers were implemented.

> Agent Advertisement messages of the target AR in the above question.

Sure. But for experimental purposes, one can simply statically configure
the access routers or FAs with the mapping.

            jak

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From: "James Kempf" <[email-masked]>
Date: Sun, 21 Apr 2002 02:43:56 -0700

jak

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From: "Eunsoo Shim" <[email-masked]>
Date: Sun, 21 Apr 2002 19:28:50 -0700

James,

I see. Thanks a lot.

Eunsoo
----- Original Message -----
From: "James Kempf" <[email-masked]>
To: "Eunsoo Shim" <[email-masked]>; <[email-masked]>; "Singh
Ajoy-ASINGH1" <[email-masked]>
Sent: Sunday, April 21, 2002 2:43 AM
Subject: Re: [Seamoby] Minutes for Meeting at IETF 53

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From: "Eunsoo Shim" <[email-masked]>
Date: Sun, 21 Apr 2002 19:28:50 -0700

James,

I see. Thanks a lot.

Eunsoo