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

From: "Hemant Chaskar" <[email-masked]>
Date: Tue, 16 Apr 2002 14:56:42

Hi Glenn:

See some comments below:

>From: "Glenn Morrow"<[email-masked]>
>To: [email-masked]
>Subject: RE: [Seamoby] Minutes for Meeting at IETF 53
>Date: Mon, 15 Apr 2002 15:55:47 -0500
>
>Excuse me for not being at the WG meeting due to a conflict but I do have
>some comments on the meeting minutes.
>
>[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.

>
>Even if the NIC can handle multiple technologies what if it can't do the
>multiple technologies simulateneously?

----clip-----------------------
>
>[Non-technical commentary - atheism]
>The end to end thing is always a good thing to think of BUT keep in mind
>that they only reason you do things to the network if to do something the
>hosts can't do or its less expensive to deploy. Nobody ever wants to add
>something to the network if they can avoid it. I just think that this might
>be one of those cases when you can't avoid it. The IP addresses are not L2
>stuff.

[HC] Also, in handoff philosophy in general, access routers do maintain 
state and transfer it from AR to AR, for example context transfer. If that 
is OK with end-to-end principle, then it seems that CARD protocol whose 
operations are confined to ARs (and of course MNs) on the periphery of the 
network should fit in the principle as well.

>
>[Administrative Commentary]
>If the WG just doesn't want to deal with the administrative hassle of 
>making
>network based CAR discovery automatic or zero-conf-like similar to dynamic
>routing, then just say all we want to do is make this configurable at this
>time or spin it off into another WG that does want to agree on a way to
>dynamically convey this information. Also as I recall, the early 
>antagonists
>of dynamic routing also said it wouldn't scale. Gee you could also pawn it
>off on AAA. Whoaa - hot potata - hot patata.
>
>Keep in mind the excuses and needs for dynamic routing are analogous to the
>excuses and needs for dynamic CAR discovery. i.e. sometimes you need it and
>want it and sometimes ya don't.
>
>Hope this helps,
>
>Glenn
>
>[Solve it for routers and the hosts are a breeze]
>p.s. you'll probably bump into the same problem again in the Monet WG where
>the correct thing to do should be pretty blatent.

_________________________________________________________________
Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp.

_______________________________________________
Seamoby mailing list
[email-masked]
https://www1.ietf.org/mailman/listinfo/seamoby

---

From: "James Kempf" <[email-masked]>
Date: Tue, 16 Apr 2002 10:26:45 -0700

> any case, address translation part of CARD will be required in this
case for

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.
Capabilities aren't involved, except to the extent that the MN can hear
multiple L2s and make the decision. But this is exactly the same as for
the intertechnology case.

            jak

---

From: "James Kempf" <[email-masked]>
Date: Tue, 16 Apr 2002 10:26:45 -0700

jak