Subject: Re: [MOBILE-IP] PPP support in 3Gwireless

From: Basavaraj Patil <[email-masked]>
Date: Wed, 17 Nov 1999 11:54:04 -0600

I think the discussion on PPP is outside the scope of the Mobile IP WG
charter. In the context of the Mobile IP WG and the decisions made by
CDMA2000 w.r.t the link layer, I believe this thread has gone far enough.
So I do not see anything more to gain here by continuing this discussion on
this mailing list.

-Basavaraj

> -----Original Message-----
>
> At 09:18 AM 11/16/1999 , Tom Hiller wrote:
> >
> >Thus, Mobile IP provides a persistent addresses with very
> wide mobility,
> >but PPP implementations need to be "enhanced" to not reset
> the rest of the
> >IP stack for Mobile IP users. For those users in which PPP is not
> >"enhanced" and no Mobile IP client exists on their device,
> cdma2000 users
> >will still have a some mobility that is not as extensive as
> supported by
> >Mobile IP.
> >
>
> I would like to add my voice behind Tom's here.  I have been
> expounding for
> a couple of years about poorly behaving PPP stacks.
> Unfortunately my words
> seem to fall on deaf ears as the stack in question is still
> broken in the
> exact same way.  I recently gave a presentation outlining PPP related
> inter-operability issues related to cdma2000 packet data.  There are
> several issues that relate to this particular stack, and resetting the
> upper layers is not the only one.  I am hoping that pressure
> from a bunch
> of different places will force our friends in Redmond to get
> it together
> and fix their stack.
>
>
>

---

From: Patrice Calhoun <[email-masked]>
Date: Wed, 17 Nov 1999 10:19:26 -0800

>At 09:38 AM 11/17/1999 , Patrice Calhoun wrote:
>>Of course, one could always simply do away with PPP, which btw is not
>>required in CDMA2000 (for mobile ip service), and make use of PPP's
>>framing, which is HDLC. This would simplify the whole network, reduce the
>>number of bits over the air, eliminate a huge potential for
>>mis-configuration on the mobile, etc.
>
>This in theory is true, but I have a couple of problems with this.
>
>1) One of the worst things about PPP (in this context) is the
>   asynchronous HDLC framing - this imposes a hefty overhead due to
>   the escaping.

I wasn't proposing asynchronous. In fact, synchronous is perfectly
legal here. It really isn't clear to me why ANY stuffing and/or
escaping is necessary at all.

>
>2) PPP is everywhere.  People get PPP for free with their OS's
>   (granted there are problems with the MS implementation) but who is
>   going to pay money for software that (from a consumer perspective)
>   does exactly the same thing as PPP, when PPP is free?  It also has
>   the potential of complicating the mobile (which is far too
>   complicated as it is because of call processing issues - another
>   discussion that) as it may have to implement BOTH PPP and the HDLC
>   derivative.  One of the great advantages off (a properly behaving
>   PPP) is that the mobile can operate in Relay Model mode (which
>   makes it essentially a byte pipe) and this SIGNIFICANTLY improves
>   the performance of the mobile.

hmmm.... PPP is free, so we should use it. TCP is also free, and I wouldn't
recommend that we run Mobile IP frames within it. This is a largely weak
argument, IMHO. I believe that the air resources, network complexity AND
the need for additional tech support should outweight such an argument.

>
>
>I think an alternative is only truly useful/worthwhile if:
>1) IETF standard protocol
IETF doesn't do link layers (with a few exceptions), but HDLC *is* a standard.
Here are a few pointers:
   [2]   ISO/IEC 3309:1991(E), "Information Technology -
         Telecommunications and information exchange between systems -
         High-level data link control (HDLC) procedures - Frame
         structure", International Organization For Standardization,
         Fourth edition 1991-06-01.
   [3]   ISO/IEC 3309:1991/Amd.2:1992(E), "Information Technology -
         Telecommunications and information exchange between systems -
         High-level data link control (HDLC) procedures - Frame
         structure - Amendment 2: Extended transparency options for
         start/stop transmission", International Organization For
         Standardization, 1992-01-15.
   [4]   ISO/IEC 4335:1991(E), "Information Technology -
         Telecommunications and information exchange between systems -
         High-level data link control (HDLC) procedures - Elements of
         procedures", International Organization For Standardization,
         Fourth edition 1991-09-15.

>2) Commonly implemented, and distributed with relevant OS's

If there is a need for an HDLC driver, which btw is MUCH simpler than PPP, I
am sure that someone can make it available. The user *will* have to install
Mobile IP anyways (as you know, Windows doesn't include it), so an HDLC
driver is a fairly simply thing to add.

>3) Does not use escaping
Absolutely!

PatC
>
>Granted the third issue is not as key as there are ways of dealing with the
>framing.
>
>>>>Thus, Mobile IP provides a persistent addresses with very wide mobility,
>>>>but PPP implementations need to be "enhanced" to not reset the rest of the
>>>>"enhanced" and no Mobile IP client exists on their device, cdma2000 users
>>>>will still have a some mobility that is not as extensive as supported by
>>>>Mobile IP.
>>>>
>>>
>>>I would like to add my voice behind Tom's here.  I have been expounding for
>>>a couple of years about poorly behaving PPP stacks.  Unfortunately my words
>>>seem to fall on deaf ears as the stack in question is still broken in the
>>>upper layers is not the only one.  I am hoping that pressure from a bunch
>>>of different places will force our friends in Redmond to get it together
>>>and fix their stack.
>>>
>
>
>
>------------------------------------------------------------------
>Marcello Lioy                                 Voice: (619)651-8220
>Qualcomm Inc.                                 PGR:   (619)635-0867

---

From: "Lipford, Mark" <[email-masked]>
Date: Wed, 17 Nov 1999 17:07:47 -0600

Point 1 (Microsoft implementing PPP) I agree we need this to happen.

Your point 2 is confusing.  How does implementing IS-707 model in the mobile
help?  The fact is we MUST utilize IS-707 between the mobile and the PDSN.
That is the standard that defines how data (packet, circuit, digital fax,
analog fax) is sent over bother a 2G CDMA network (IS-95a and IS-95b)
network, and a cdma2000 (3G) network.  Is has nothing to do with PPP.
IS-707 only defines how data is sent over the RF network that is using
cdmaOne or cdma2000 physical channels.

Please explain.

                -----Original Message-----
                From:   Jim Willkie [mailto:[email-masked]]
                Sent:   Wednesday, November 17, 1999 11:05 AM
                To:     [email-masked]
                Subject:        Re: [MOBILE-IP] PPP support in 3Gwireless

                Folks:
                Below I'd like to add a bit to Tom's comments...

                At 11:18 AM 11/16/99 -0600, Tom Hiller wrote:
                >Quiang,
                >
                >PPP at this stage of cdma2000 standards is "automatic" in
the sense we have no
                >other link protocol to the user: The user must run PPP. In
a future version
                >cdma2000 may have an alternate data link. This is uncertain
at the moment.
                >
                >Generally cdma2000 supports two access mechanisms. (1) PPP
access (2)
                Mobile IP
                >
                >When the mobile moves to a new Packet Data Service Node
(PDSN -- contains
                a NAS
                >and FA), the PDSN will restart PPP to the mobile
automatically. It is a
                >requirement that that a PPP implementation not reset the
entire IP stack above
                >it for Mobile IP.
                >
                >A given PDSN will have moderately wide coverage (e.g. a
large city) for a
                >couple
                >of reasons: (1) there is an Radio Access Networks (RAN) to
PDSN interface that
                >supports mobility between multiple RANs while maintaining
connectivity to the
                >same PDSN so that PPP needs to restart less frequently (2)
Some deployed Radio
                >Access Networks are really quite large and cover much of a
large city.
                >Thus, Mobile IP provides a persistent addresses with very
wide mobility, but
                >PPP
                >implementations need to be "enhanced" to not reset the rest
of the IP
                stack for
                >Mobile IP users. For those users in which PPP is not
"enhanced" and no
                >Mobile IP
                >client exists on their device, cdma2000 users will still
have a some mobility
                >that is not as extensive as supported by Mobile IP.

                There are actually 2 means available to avoid the 'resetting
the IP stack':
                1) get Microsoft to make their PPP implementation(s) to
behave correctly or
                2) implement the IS-707* Packet Network model in the mobile.

                For a MobileIP solution the Network model method is viewed
(here at QC at
                least) as required anyway in order to perform Mobile Node
registration at
                the mobile. So this would make the poorly behaving Msoft PPP
a mute point,
                at least for the MobileIP case.

                Jim Willkie

                >Qiang Zhang wrote:
                >>
                >> I have questions regarding the PPP support in the 3G
wireless network,
                >> please clarify.
                >>
                >> Would the PPP support tend to be very automatic? Thus,
being transparent to
                >> the user, the device will be able to initiate PPP session
whenever it enters
                >> a new network, is this true?    If it is true, we know
this will have impact
                >> on the applications because if there is a "release IP"
and "obtain new IP"
                >> procedure, a lot applications  basically just chicken
out.
                >>
                >> Is there solution out there already it is left to the
implementations? Where
                >> can I find corresponding document if any. Thank you!
                >>
                >> -Qiang
                >>
                >> 1100 Warnings!
                >> --Line 100000: 3 cokes shut down your immune system for
24 hours, so stay
                >> away from sodas!

---

From: Basavaraj Patil <[email-masked]>
Date: Wed, 17 Nov 1999 17:19:03 -0600

Mark,

I need to say this again, but this is the Mobile IP mailing list.
This discussion really does not belong on this list. Please keep the
discussions focused to issues relevant to Mobile IP here. If you wish to
continue this topic, please do so outside the scope of the Mobile IP
mailing list.

-Basavaraj

> From: Lipford, Mark [mailto:[email-masked]]
> Sent: Wednesday, November 17, 1999 5:08 PM

---

From: Qiang Zhang <[email-masked]>
Date: Wed, 17 Nov 1999 18:16:23 -0500

>Point 1 (Microsoft implementing PPP) I agree we need this to happen.

 In this sense, everybody needs to *enhance* PPP stack, hopefully don't have
to give a dial number again

>cdmaOne or cdma2000 physical channels.

 I don't know much about IS-707, however first of all, there is the need
that RTT layer exposes a service point to upper layer indicating the Handoff
status, then the device can go further to set up link layer connection
unless the link establishment can be initiated from service end.

 BR
 Qiang