Subject: Re: [MOBILE-IP] Hand-over resend

From: Patrice Calhoun <[email-masked]>
Date: Tue, 2 May 2000 12:18:31 -0700

Amen!

PatC
>Phil:
>
>Following up on your note:
>
>I think it would be a mistake to have the Mobile IP Working
>Group do a 3GIP kind of thing or be a vehicle for 2/3G
>transition to wireless Internet.
>
>The Mobile IP WG should charter 4GIP: pure unadulterated
>IP packet networks based on Mobile IP and packets to
>and from the mobile host using best effort service.
>
>I think too much 3G influence in the group may
>be a distraction from that.
>
>Andrew
>
>Roberts Phil-QA3445 wrote:
>>
>> Alan,
>>
>>         this was on the mail list.  We were letting people say pretty much
>> whatever they wanted on this issue last week so I didn't respond.
>>
>>         I now have a couple of comments.
>>
>>         Although a sizeable constituency of the group has the same goal of
>> an all IP mobile enabled network for cellular, the group is not chartered to
>> come up with a transition plan for something like UMTS.  That's not to say
>> such isn't needed, it's just beyond the scope of this group.  If there are
>> particular aspects of that kind of work that fall into our charter (such as
>> supporting fast handovers) we're certainly willing to take contributions.
>>
>>         As far as forming something like a BOF to investigate the appraoch
>> you've outlined, there may be members of this list who are interested in
>> participating, but we're not really the right audience to ask for such an
>> agenda item.
>>
>> Hope this helps,
>> Phil
>>
>> -----Original Message-----
>> From: Alan O'Neill [mailto:[email-masked]]
>> Sent: Tuesday, May 02, 2000 9:25 AM
>> To: [email-masked]
>> Subject: Re: [MOBILE-IP] Hand-over resend
>>
>> Folks,
>>
>> The following message was sent to the list last week and whilst it is on the
>> Nortel archive, it appears it did not hit the main list ?
>>
>> Date:         Fri, 28 Apr 2000 08:15:51 -0400
>>                     Reply-To:     Alan O'Neill <[email-masked]>
>>                     Sender:       "IP Routing for Wireless/Mobile Hosts
>> (mobile-ip)"
>>                                   <[email-masked]>
>>                     From:         Alan O'Neill <[email-masked]>
>>                     Subject:      Re: handover
>>
>>                     All,
>>
>>                     For those who do not know me I work in BT on all IP
>> architecture with primary focus on UMTS Rel2001 but also including mobility
>>                     across a range of access technologies. I am also
>> co-author of <draft-oneill-ema-01.txt> which attempts to provide a generic
>> IP
>>                     hand-over architecture which will support UMTS:GTP,
>> MobileIP, but mainly routed mobility. Co-authors are Scott Corson the
>>                     MANET wg co-chair and George Tsirtsis also of BT.
>>
>>                     We would like to to see  hand-over control and
>> interactions with the radio systems to be defined in a
>>                     generalised way so that an operator can migrate from
>> existing GTP through possibly MobileIP to the holy grail of a scalable
>>                     mobile enhanced routing protocol (we use modified
>> MANET:TORA for this at the moment), with co-existence where commercial
>>                     models dictate for the data-path options (tunnelled /
>> routed etc) . The aim is to facilitate a common IP hand-over interface so
>> that
>>                     the operator can have all options co-exist, and support
>> evolution between them. We can also see big dangers and interoperability
>>                     problems if each affected working group designs it's
>> own, non-interworking  fast IP hand-over solutions and associated interfaces
>>                     into the access technologies and systems.
>>
>>                     The Edge mobility Architecture draft
>> <draft-oneill-ema-01.txt> avoids many of the details but hopefully the
>> reader can see the
>>                     clear need to enable tunnelled and native routed
>> solutions to co-exist,  re-using the same AAA, access signalling and policy
>>                     elements, plus the interfaces into many different access
>> technologies and systems. Our view at this stage is that the solution for
>>                     the signalling plane requires a combination of extended
>> MobileIP signalling to embrace GTP and routed mobility requirements,
>>                     plus DHCP extensions. We are presently preparing drafts
>> which detail the mapping of EMA to UMTS, and  the detailed signalling
>>                     pieces.
>>
>>                     It seems to make sense that a separate short working
>> group be first formed to define the scope and
>>                     architecture for the IP hand-over work so that common
>> pieces can be identified along with the full set of new protocol
>>                     requirements. We can then let each existing or resulting
>> working group deal with those protocol requirements which clearly will
>>                     include MobileIP. Possibly a BOF could be specifically
>> scheduled at the next IETF or even some sort of interim meeting given
>>                     the all-IP timescales we are all experiencing in this
>> space.
>>
>>                     Comments appreciated.
>>
>>                     Regards
>>                     Alan O'Neill, Scott Corson, George Tsirtsis....

---

From: Roberts Phil-QA3445 <[email-masked]>
Date: Tue, 2 May 2000 14:18:59 -0500

Hi,

        I agree that we don't have the scope of organizations that are not
only interested in developing protocols but also developing system
architectures.

        I find it difficult to agree with your perspective on 3G network
support, and actually what constitutes 3G networks for that matter.  All
constituencies with an interest in Mobile IP are welcome here.  We're not
going to design 3G cellular networks, but if the folks who are would like
something added to mobile ip in order to use it in their networks they are
more than welcome to contribute, and have been doing so in fact.

Phil

-----Original Message-----
From: Andrew T. Campbell [mailto:[email-masked]]
Sent: Tuesday, May 02, 2000 4:40 PM
To: Roberts Phil-QA3445
Cc: [email-masked]
Subject: Re: [MOBILE-IP] Hand-over resend

Phil:

Andrew

---

From: Raja Narayanan <[email-masked]>
Date: Wed, 3 May 2000 08:58:52 -0500

I agree with this viewpoint....especially the last paragraph.

--Raja

-----Original Message-----
From: C. Perkins/D. Reese [mailto:[email-masked]]
Sent: Tuesday, May 02, 2000 1:48 PM
To: [email-masked]
Subject: Re: [MOBILE-IP] Hand-over resend

Hello Andrew,

I think it would be a mistake to limit the involvement of
3G proponents.  Instead, I would hope that we would
identify the correct charter items, and solicit input from
all interested parties along the way towards fulfilling
the charter work items.  Just as an example -- if, for
instance, some 3G folks need to have certain Route
Optimization features that are independent of the access
medium, that is a discussion which belongs here.

Part of the reason I am reacting to this is that I have
spent a lot of time encouraging 3G engineers to get
more involved with the mobile-ip working group.
They should be welcomed, and we should all make
sure that we understand clearly the goals of the working
group.

One notable difference is that the mobile-ip working
group is mostly chartered to do protocols, whereas
3G standardization groups also have to put together
system architectures.  Thus, they are likely to notice
when a protocol component is missing.  That is good
information for us to know.

Regards,
Charlie P.

---

From: Raja Narayanan <[email-masked]>
Date: Tue, 2 May 2000 14:53:21 -0500

--Raja

-----Original Message-----
From: C. Perkins/D. Reese [mailto:[email-masked]]
Sent: Tuesday, May 02, 2000 1:48 PM
To: [email-masked]
Subject: Re: [MOBILE-IP] Hand-over resend

Hello Andrew,

Regards,
Charlie P.

---

From: "Alan O'Neill" <[email-masked]>
Date: Tue, 9 May 2000 17:03:26 +0100

Phil (folks),

>
>Hi,
>
>        I agree that we don't have the scope of organizations that are
>not only interested in developing protocols but also developing system
>architectures.
>
>Phil Roberts

I just wanted to allay some fears that we were suggesting that MIP should
undertake UMTS evolution work which is most definitely not what we want,
and yes Phil we are more than keen to contribute to the MIP work but I
think it important for us to explain a little more what we are worried
about and why GTP/MIP/TORA are involved in this space.

Draft-oneill-ema-01.txt is targeted at controlling IP hand-over between
Access Routers (ie the first IP aware boxes) in the same routed domain.
[For those struggling with the draft see
http://www.isr.umd.edu/TechReports/ISR/2000/TR_2000-5/TR_2000-5.phtml]
Between the AR and the MH could be a range of radio or fixed
technologies, some of which have there own imbedded mobility mechanisms.
The AR for UMTS in our work is assumed to be the SGSN in the early days
but migrating out to the RNC as it becomes more IP enabled/compliant.
Inter-domain hand-over (which we believe will be very rare but potentially
useful) requires MobileIP.

Inter-SGSN and (in the future) inter-RNC hand-overs in the UMTS specs use an
IP tunnel technique called GTP (also see draft-casati-gtp-00.txt), which
exists between a core anchor point called the GGSN, and the present SGSN.
SGSN hand-over involves building a temporary tunnel between the two SGSNs
(old and new) to forward received data at the OLD SGSN, whilst a new GTP
tunnel is constructed between the new SGSN and the same GGSN anchor point.
The GGSN looks a little like the MIP HA, whilst the two SGSN's look like two
Fas in the 3GPP2 model. The significant difference though is two-fold.
Firstly, the existence of the temporary hand-over tunnel between FAs, and
secondly, the fact that GTP tunnel management is closely bound to, and
controlled by, the cellular signalling.

EMA is a fusion of "planned" hand-over (routed at the OLD AR/SGSN/RNC etc),
where the hand-over is controlled using cellular signalling/measurements
etc, and "unplanned" hand-over (routed at the new AR etc), where hand-over
to/from/ between access technologies is not supported by cellular
signalling. Note that unplanned includes the case  where cellular hand-over
fails due to unplanned loss of connectivity to the old AR/SGSN/RNC.

For planned hand-over, a temporary tunnel MAY be used between the two
AR's, in a similar manner to that effected by GTP today because the system
knows in advance where the MH is being handed over to. With unplanned
hand-over, the old AR does not know where to hand-over to (so cannot build
a temporary tunnel), until the MH arrives at the new AR and signals back.
Note that the EMA hand-over model is similar to MIP if the HA is the old
AR and the FA is the new AR (although this does stretch things a little
bit).

What is clear though is the following, which I think should be considered,
and which we would like to both support and contribute to;

1)      MIP has an existing and developing signalling plane which is to be
evolved to embrace the GTP type requirement in 3GPP2. If it can fully
support the 3GPP GTP requirement then we can evolve to a single common
solution to the anchor scenario, and hence provide better support for
3G.PP / 3G.PP2 inter-working.....I believe that the inter-working and GTP
requirements and interfaces for MIP should of course be done in 3GPPx.
2)      EMA is likely to first use GTP temporary tunnels between old and new
AR's (as it exists), but we would wish to migrate to MIP both because of
(1), and the fact that the AR's will need MIP later on anyway for
inter-domain EMA support. Clearly if we can get MIP in before EMA then EMA
can avoid GTP in the first phase.
3)      EMA itself would like to be able to re-use the MIP signalling plane
only. MIPsig deals well with the AAA requirements, this approach would
provide co-existence of both tunnelled and native options (which is
commercially important), provides a simple migration path to EMA from MIP
(from tunnelled to native forwarding) in the future, and again provides us
with the fully integrated inter-domain MIP piece.
4)      Failure to address this here and now (same/very similar technical
requirement for slightly different scenario) could lead to multiple,
distinct, non-interworking IP hand-over signalling planes in cellular
(note we already have GTP v MIP out of the bag). I hope we can avoid this
when it seems to us we are trying to do such similar things !
5)      There is in addition to the above a range of mobility related
signalling issues which I think affect MIPs evolution in this space, and
it's relationship to other working groups activities...Maybe this is the
BOF issue...

So I guess I have to ask the chairs and you list folks if what I am asking
is unreasonable, and what if any of the above areas are, and are not,
going to be welcome as technical input into this wg ??

Regards,  Alan.
------------------------------

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