Subject: Re: [Seamoby] Examples of CAR discovery

From: "Hemant Chaskar" <[email-masked]>
Date: Mon, 25 Mar 2002 21:32:33

Hi:

Some comments below:

>From: "James Kempf" <[email-masked]>
>To: "Eunsoo Shim" <[email-masked]>, <[email-masked]>
>Subject: Re: [Seamoby] Examples of CAR discovery
>Date: Mon, 25 Mar 2002 11:03:08 -0800
>
> > Please just let me remind you that the CAR discovery protocol also
>provides
> > mapping of L2 ID to IP address of the new AR which is necessary for
>the
> > low-latency handoff mechanism proposed in the MobileIP WG. So there is
>a
> > case CAR discovery is helpful for single technology handovers.
> >
>
>OK, so what you are saying is that there are two cases:
>
>1) Provding the MN with CAR information on what choices are available
>or, possibly, when the MN moves into an area where a new choice is
>possible, like moving into a hot spot area, for MNs that have multiple
>interfaces.
>
>2) Providing the AR with reverse address translation for CARs for MNs
>that have single interfaces and want fast handover support.
>

>I agree.
>
>I don't get the feeling that these two cases are clearly delineated in
>the requirements. In fact, they seem to me like they are really two
>separate protocols.

[HC] From the requirements perspective, what all the recent discussion is 
about is probably the following requirement text (with supporting line that 
CAR discovery is about comparing MN's requirements with GAAR capabilities 
and slecting CARs from GAARs):

"CAR discovery output MUST be retrievable, possibly selectively, by MN".
Also, I assume that there will the the following requirement as well (I 
think that this was posted before IETF53 and I also saw some WG members 
endorse it in IETF53 meeting): "MN requirements MUST be made available for 
CAR discovery".

This would mandate a CAR discovery functionality as follows:

MN Requirements --(parameters)--> CAR Discovery Module --(output)--> MN
                                       ^
                                       |
                                       |
                         Capability information about GAARs

Again, "CAR discovery module" can reside completely in MN, completely in AR 
or combination depending upon environment, availability of multiplicity of 
interfaces with MN etc. Further, the nature of MN requirements input and 
corresponding output depends upon the environement in which CAR discovery is 
being used. Also, whether the solution is organized into seperate protocols 
or single protocol is a solution-specific aspect.

(Note: The first requirement in requiremnet spec already says the address 
translation part. We can keep it so given its importance for fast/seamless 
handoffs, though it can be subsumed into above generic model (with "one 
parameter = L2 id", "one capability information about GAARs = L2 to IP addr. 
maps" and "output=IP address of CAR").)

>
> > I understand the IETF is pro-end-point-control. Anyway, regarding your
> > question, couldn't we imagine a case when a network provider wants do
>a kind
> > of load-balancing between different access networks in the wireless
>overlay
> > network?
> >
>
>Sure, but I think that's a very special case. The more general case (and
>in fact, the case that is showing up *today*) is that one network
>provider owns one medium and the other another. Example: at the airport,
>the cellular provider owns the CDMA network and some WLAN provider owns
>the WLAN network.

[HC]There is a concept of operator owned WLAN that is actually catching up. 
Some systems are already rolled out in Europe if I am not mistaken. So, both 
cases are very important - two media owned by two operators and two media 
owned by single operator.

BR,
Hemant

_________________________________________________________________
MSN Photos is the easiest way to share and print your photos: 
http://photos.msn.com/support/worldwide.aspx

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

---

From: "James Kempf" <[email-masked]>
Date: Tue, 26 Mar 2002 08:33:18 -0800

Hemant,

I prefer wording that specifically requires the MN to be involved in
getting the CAR information. Thus:

    The CAR discovery protocol MUST provide the MN with GAAR
information, along with capabilities.

This is clear and unambiguous about what network entity is in control
during an intertechnology handover.

            jak

---

From: "James Kempf" <[email-masked]>
Date: Tue, 26 Mar 2002 08:33:18 -0800

Hemant,

            jak

---

From: "Henrik Levkowetz" <[email-masked]>
Date: Tue, 26 Mar 2002 23:11:00 +0100

I support James' proposal.

	Regards,
		Henrik

---

From: "Henrik Levkowetz" <[email-masked]>
Date: Tue, 26 Mar 2002 23:11:00 +0100

Regards,
		Henrik