Subject: Re: [MOBILE-IP] Handoff framework [Was Re: [MOBILE-IP] Anothernovicequestions!]

From: James Kempf <[email-masked]>
Date: Mon, 14 Aug 2000 12:50:26 -0700

Yingchun,

>In general, there are two approachs to abstract an Access Network:
>1. Abstract Link Layer Protocol: Defining an common link layer protocol to
>extend various Access Network to FA.
> By doing this, an FA will only need to understand the Abstract link layer
>protocol (or Abstract Access Network).
>Each Access Network will be
>responsible for translating (or mapping) its specific link layer to the
Abstract
>link layer.
>
>In 3G cdma2000, the RP interface protocol (to some extent) is an extension of
>cdma2000 link layer.
>
>2. Link Layer Specific FA: This will make every Access Network has its own
>specific FA. The FA will be fully
>knowledgable of a specific link layer (or Access Network).  This method tries
to
>abstract Access Network
>at network layer so that from HA point of view, all Access Network are same.
>Unfortunately, it makes Mobile IP
>depending on specific link layer.
>
>Method 1 is prefered since it makes Mobile IP independent of any specific link
>layer protocol (but still dependent of
>the common Abstract link layer).

These are implementation stratagies that can be useful, but I think they
are somewhat independent of the specification. If the specification is
developed in terms of an abstract description of the link layer, then
implementors can choose one or the other of these implementation stratagies,
or potentially another one.

                jak

---

From: Michael Kounavis <[email-masked]>
Date: Tue, 15 Aug 2000 14:20:43 -0400

>This appears to be what we had been proposing the WG should do. The basic
idea
>is to come up with some basic capabilities that link layers have, which
could
>be used to perform the handoff execution process. Since some link layers
are
>more complex than others, some may provide better handoff performance.
>
>PatC

Pat,

In addition to  link layer abstractions, however one could think of many
other types of 'open' interfaces between access network components.

This goes beyond the definition of an abstract link layer interface. This
calls for new technologies to extend the capabilities software radfios offer
to the signaling plane of mobile and wireless networks.

For example, if you have a generic 'handoff execution interface'
that separates the handoff detection algorithms from the handoff
execution algorithms you can deploy multiple styles of handoff
control (e.g., MAHO, MCHO) on the same wireless network;
Different handoff styles would seamlessly share the underlying
mobility management system (e.g., HAWAII, CIP) etc.

The same generic interface can be used for 'plugging' different
signaling systems into mobile devices allowing to roam accross
heterogeneous access networks. In this way, you  address the
inter-system handoff problem.

So my point is that there are technologies, which are being
investigated in the academia, that can be leveraged by
the Mobile IP WG where and when needed -as in the case
of the abstract link layer.

--Michael

---

From: [email-masked]
Date: Wed, 16 Aug 2000 10:19:32 -0500

I agree that the Abstract link layer requirements or primitives should be part
of Mobile IP WG. As far as how to implement the primitives, it is beyond the WG.

Agreed that RP like extension to cdma2000 network is just an example of the
implementation.

---Yingchun.

"Ajoy Singh" <[email-masked]> on 08/15/2000 11:28:29 AM

Sent by:  "Ajoy Singh" <[email-masked]>

To:   Yingchun Xu/MW/US/3Com, [email-masked]
cc:
Subject:  RE: [MOBILE-IP] Handoff framework [Was Re: [MOBILE-IP]
      Anothernovicequestions!]

Hi All,
I also agree with the idea of link layer trigger being used to trigger
mobile/IP handover. I also think it is possible to define a common link
layer extension to make FA implementation independent of link layer details.
I guess it might be enough to define a link layer primitive which will be
sent from link layer to network layer whenever handover event is detected.
The handover draft can define what it expects in the link layer handover
primitive.  It will be job of the respective link layers to provide the
information required by handover primitive to layer 3. This way the foreign
agent implementation will be independent of link layer. I am not in favor of
proposing complete new RP like protocol between radio access network and
foreign agent as generic protocol might not be suitable to different access
technologies and moreover Mobile/IP may not be right place to define such
link layer protocol extension. In case of CDMA 2000, RP may be extended to
accommodate information required by handover primitive. Any suggestions ?
regards,
ajoy

-----Original Message-----
From: IP Routing for Wireless/Mobile Hosts (mobile-ip)
[mailto:[email-masked]]On Behalf Of
[email-masked]
Sent: Tuesday, August 15, 2000 12:27 AM
To: [email-masked]
Subject: Re: [MOBILE-IP] Handoff framework [Was Re: [MOBILE-IP]
Anothernovicequestions!]

Pat,
I was not proposing each wireless standard body making Mobile IP work. On
the
contrary, I am proposing that each wireless standard body should map its
Access
Network specific link layer into a common Abstract link layer defined by
Mobile
IP WG. This will free Mobile IP from specific Link Layer dependent.

This can be achieved by implementing a common link layer protocol extension.

Without this common Link Layer protocol, each FA implementation will be
dependent on each specific Link Layer.

That's all I am trying to say. Hope I am not mislead you. God know how you
come
up so much conclusion.

---Yingchun.

"pcalhoun/@eng.sun.com" <Pat.Calhoun on 08/14/2000 03:40:44 PM

Please respond to "[email-masked]" <[email-masked]>

Sent by:  "[email-masked]" <Pat.Calhoun

To:   Yingchun Xu/MW/US/3Com
cc:   [email-masked]
Subject:  Re: [MOBILE-IP] Handoff framework [Was Re: [MOBILE-IP]
      Anothernovicequestions!]

> I agreed with Jim. In fact, the approach has been used to some extent in
3G
> cdma2000 wireless network.
>
> Abstract link layer.
> knowledgable of a specific link layer (or Access Network).  This method
> tries to abstract Access Network
> Method 1 is prefered since it makes Mobile IP independent of any specific
> link layer protocol (but still dependent of
So, let's see if I get this correct.

You propose that each wireless standard try to figure out how to get Mobile
IP
working correctly, as opposed to Mobile IP providing a set of tools for the
wireless standards people to use.

Do you not believe that the IETF is where any Mobile IP work should be done?
Do people really want to see solutions like the 3G ext, where PPP is carried
in GRE, and god knows what other standard body comes up with, as opposed to
a
*single* nice clean solution?

I much prefer #2 above, but I do not like the way you've put it. How about:

"2. The Mobile IP WG will develop a single fast handoff strategy, that takes
advantage of certain wireless technology capabilities. The document will
include support for complex air interfaces (e.g. ones that provide air
interface measurements), and simpler ones (e.g. ones that do not provide
such
measurements)."

PatC