Subject: RE: [Mipshop] new charter

From: "Singh Ajoy-ASINGH1" <[email-masked]>
Date: Sat, 8 Oct 2005 23:44:48 -0400

Alex, 

I like your proposal. This is a better way to enable communication
between 802.21 and IETF without defining any WG work items till .21
requirements are complete. 

Regards,
Ajoy 

-----Original Message-----
From: Petrescu Alexandru-AAP021 
Sent: Saturday, October 08, 2005 7:13 AM
To: James Kempf
Cc: Singh Ajoy-ASINGH1; [email-masked];
[email-masked]; [email-masked]
Subject: Re: [Mipshop] new charter

James Kempf wrote:
> It seems to me that if 802.21 wants IETF to work on a protocol, it 
> should bring in the requirements then have the discussion in the
> MIPSHOP WG what the appropriate protocol is. On the other hand, if
> 802.21 wants to do the protocol itself, then it can do the design
> itself and IETF doesn't need to be involved.
> 
> I think what I would not find acceptable is for 802.21 to come to
> IETF and say "this nonstandards track protocol must be made into a
> standards track protocol without any changes".

I understand that and I share that perspective.

One possible way to efficiently liaise 802.21 activities with mipshop
activities, and to avoid the situation described above, could be for the
mipshop Charter to suggest the following:

"This WG meetings will offer presentation slots for reports from the
 802.21 TG whenever 802.21 representatives need.  The WG will be
 solicited feedback on these presentations and will provide technical
 advice when requested.  The 802.21 activities will be described in
 personal Internet Drafts, and they will not become mipshop WG items."

I think this will help interactions between the two groups.  Adding
anything more than that to the current charter and knowing the current
advancement of 802.21 is probably a little bit premature.

Later on, when 802.21 requirements are set within 802.21, then WG items
I-Ds for 802.21 could be stated in the Charter.

Just some thoughts on a possibility,

Alex

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---

From: "James Kempf" <[email-masked]>
Date: Mon, 10 Oct 2005 08:53:52 -0700

The problem is that some of the items are needed for FMIP, which is a WG 
item. I'd like to see a single standard for providing handover related 
information, not two.

        jak

----- Original Message ----- 
From: "Singh Ajoy-ASINGH1" <[email-masked]>
To: "Petrescu Alexandru-AAP021" <[email-masked]>; "James 
Kempf" <[email-masked]>
Cc: <[email-masked]>; <[email-masked]>; 
<[email-masked]>
Sent: Saturday, October 08, 2005 8:44 PM
Subject: RE: [Mipshop] new charter

Alex,

Regards,
Ajoy

-----Original Message-----
From: Petrescu Alexandru-AAP021
Sent: Saturday, October 08, 2005 7:13 AM
To: James Kempf
Cc: Singh Ajoy-ASINGH1; [email-masked];

Alex

---

From: Alexandru Petrescu <[email-masked]>
Date: Mon, 10 Oct 2005 19:27:31 +0200

James Kempf wrote:
> The problem is that some of the items are needed for FMIP, which is a
> WG item. I'd like to see a single standard for providing handover
> related information, not two.

Right - single IETF doc for doing same thing, not two.

But I am afraid that the space of possible interactions between FMIP and
802.21 protocol has not been mentioned in any detail, at least not here.

802.21 happens between STA and AP, or between STA and Server (STAtion
could be assumed as a MN, "Server" could be assumed as an AR,  "AP" is
just an AP.)

But FMIP happens between MN, oAR and nAR.

FMIP leaves open the choice for distributing subnet info between ARs.
802.21 doesn't provide any means for that.

FMIP ARs periodically beacon PrRtAdvs.  But 802.21 AP or Servers do not
"beacon" (the messages 802.21 APs send are always in response to a request.)

802.21 looks at inter-system handovers, while FMIP does intra-system but
fast.

For these reasons, I do not see now what the interactions between 802.21
and FMIP could be.

Alex

---

From: Rajeev Koodli <[email-masked]>
Date: Mon, 10 Oct 2005 10:58:27 -0700

> 802.21 protocol has not been mentioned in any detail, at least not here.

Yes. However, if you look back on the ML discussion prior to Paris 
meeting, we seem to have converged to having a protocol that defines the 
handover information Request - Reply semantics. FMIP would use the 
message structure and option format in its PrRt* messages. I guess the 
IS in 802.21 is also interested in the handover information Request - 
Reply. So, perhaps it makes sense to define a single protocol (for 
handover information exchange).

> 802.21 looks at inter-system handovers, while FMIP does intra-system but

More accurate to say that 802.21 is interested in specifying handover 
information exchange (the IS part). Perhaps the other part (ES/CS) could 
also help but I doubt if their intent is to provide a L3 handover 
protocol. I hope not!

Note that FMIP is not limited to intra-system handovers alone. certainly 
we need more experimental data for inter-system handovers, but our own 
experience suggests that inter-system "IP soft handovers" could use a 
more robust forwarding mechanism (i.e., predictively setting up a tunnel 
from PAR to NAR greatly improves handover success).
This is another topic!

-Rajeev

---

From: Alexandru Petrescu <[email-masked]>
Date: Mon, 10 Oct 2005 21:02:34 +0200

Rajeev Koodli wrote:

>> But I am afraid that the space of possible interactions between 
>> FMIP and 802.21 protocol has not been mentioned in any detail, at 
>> least not here.
> 
> 
> meeting, we seem to have converged to having a protocol that defines
>  the handover information Request - Reply semantics.

Thanks for pointing to that.  I've read the thread titled "Interest in
..." around July 15.  Chairs decide what's convergence.  I personally
agree with the mail that says that generally 802. stuff is below IP.

> FMIP would use the message structure and option format in its PrRt* 
> messages. I guess the IS in 802.21 is also interested in the handover
>  information Request - Reply. So, perhaps it makes sense to define a 
> single protocol (for handover information exchange).

Is there an FMIP message equivalent to the 802.21 MIH Information Request?

>> 802.21 looks at inter-system handovers, while FMIP does 
>> intra-system but fast.
> 
> 
>  information exchange (the IS part).

Yes, other messages mention that the IS part should be encoded
meaningfully for 802.21 and FMIP.  Would it make sense to encode that
with XML?  That would dispose the issue to yet another SDO.

> Perhaps the other part (ES/CS) could also help but I doubt if their
> intent is to provide a L3 handover protocol. I hope not!
> 
> Note that FMIP is not limited to intra-system handovers alone.

Rajeev, it is ok to mention on electronic text that a certain protocol
is intended to do something.  And at the same time I think that all
reported experimentation with FMIP has always been intra-system, more
specifically 802.11b (a and g in some cases).  That's what I meant by
intra-system, same MAC layer.

While I agree that FMIP is not conceptually limited to intra-system
handovers I can also speculate that the FMIP protocol can bring little
or no advantage at all when used heterogeneously between for example
802.11b and GPRS.

> certainly we need more experimental data for inter-system handovers,

YEs, that is needed.  Until it shows up that's all it can be said: we
need it.

> but our own experience suggests that inter-system "IP soft handovers"
> 
> 
> 
> 
What's "IP soft handovers"?

> could use a more robust forwarding mechanism (i.e., predictively 
> setting up a tunnel from PAR to NAR greatly improves handover 
> success). This is another topic!

I agree.

Alex

---

From: Rajeev Koodli <[email-masked]>
Date: Mon, 10 Oct 2005 12:28:57 -0700

> Is there an FMIP message equivalent to the 802.21 MIH Information Request?

PrRtSol is very specific to resolving L2-ID to L3-AR-Info. I wouldn't 
equate the two.

> with XML?  That would dispose the issue to yet another SDO.

The idea is to define Request-Reply messages (see for instance, the NED 
draft) and generic option structure with Type assignment from a common 
registry. FMIP PrRt* messages would use ICMP for transport (as they do 
now), but use the "harmonized" packet structure.

-Rajeev

---

From: Alexandru Petrescu <[email-masked]>
Date: Mon, 10 Oct 2005 22:26:59 +0200

> PrRtSol is very specific to resolving L2-ID to L3-AR-Info. I wouldn't

I thought RtSolPr was the primary candidate to contain data encoded in
802.21 format...  So it's not RtSolPr-PrRtAdv messages that will benefit
from 802.21...

> draft)

I've looked over the NED (NEighbourhood Discovery) draft, it's similar
and apparently competing with CARD concepts.  It also relates to an
expired draft on Network Access Co-ordination.

> and generic option structure with Type assignment from a common

(sidenote: PrRt* is actually either RtSolPr or PrRtAdv, no common
 prefix).

I understand that mipshop may consider NED's NED-RQST NED-REPLY, CARD's
Request Reply and probably Service-Request Service-Reply of an older
draft-lach-nac-01.txt, for encoding 802.21 data onto them.

We probably should think about a problem statement and requirements too.

Alex

---

From: Rajeev Koodli <[email-masked]>
Date: Mon, 10 Oct 2005 14:03:10 -0700

> (sidenote: PrRt* is actually either RtSolPr or PrRtAdv, no common

(PrRT is common, just not contiguous :-) )

> draft-lach-nac-01.txt, for encoding 802.21 data onto them.

Okay.

-Rajeev

---

From: "James Kempf" <[email-masked]>
Date: Mon, 10 Oct 2005 16:35:50 -0700

server == AR

            jak

----- Original Message ----- 
From: "Alexandru Petrescu" <[email-masked]>
To: "James Kempf" <[email-masked]>
Cc: "Singh Ajoy-ASINGH1" <[email-masked]>; "Petrescu Alexandru-AAP021" 
<[email-masked]>; <[email-masked]>; 
<[email-masked]>; <[email-masked]>
Sent: Monday, October 10, 2005 10:27 AM
Subject: Re: [Mipshop] new charter