Subject: Re: [MOBILE-IP] Cellular IP for Private Network Access

From: "Lipford, Mark" <[email-masked]>
Date: Fri, 7 Jan 2000 00:02:26 -0600

Sprint PCS would ask that the design of our network not be discussed over
ANY public mail list.  There are issues with NDA that we do not want to have
remind these companies of.  Please stop this thread with this email!

Thank you

                -----Original Message-----
                From:   Yingchun Xu [mailto:[email-masked]]
                Sent:   Thursday, January 06, 2000 9:27 AM
                To:     [email-masked]
                Subject:        Re: [MOBILE-IP] Cellular IP for Private
Network Access

                Phil,
                Sprint network does not have Cellular IP. In Cellular IP
draft, no PPP is used.
                Between GW and BS, Mobile Host IP addresses are used for
packet routing.
                Cellular IP nodes maintain Route Cache.

                The problem occurs when two Mobile Hosts accessing different
private networks
                get assigned the same IP address at WAN level. In this case,
Cellular IP node
                will have problem for IP packet routing based on Mobile Host
IP address.

                --Yingchun.

                Phil Karn <[email-masked]> on 01/05/2000 05:38:02 PM

                Please respond to Phil Karn <[email-masked]>

                Sent by:  Phil Karn <[email-masked]>

                To:   [email-masked]
                cc:    (Yingchun Xu/MW/US/3Com)
                Subject:  Re: [MOBILE-IP] Cellular IP for Private Network
Access

                >conflicted Mobile Node IP addresses may be assigned which
will cause the
                failure
                > of IP packet forwarding.

                I don't know what this means. I do know from personal
observation how
                Sprint PCS's wireless web service is set up, though. PPP
gives you an
                address on network 10, and routes you through a
bidirectional NAT in
                Kansas City. I.e., the NAT assigns you a routable address
and
                translates between that and your network 10 address without
any port
                translation.

                This forces you to run Mobile IP with tunneling in both
directions if
                you want to give your mobile computer a predictable routable
address.

                Is this what you had in mind?

                Phil

---

From: Phil Karn <[email-masked]>
Date: Fri, 7 Jan 2000 00:32:31 -0800

>remind these companies of.  Please stop this thread with this email!

My description of Sprint PCS's packet data service was based totally
on my personal observations using my personally-owned phone, a data
cable and a laptop running Linux. ANY Sprint PCS user who knows how to
use standard Linux/UNIX networking tools such as pppd, netstat and
traceroute can easily discern the very same information in a few
minutes. It can hardly be considered proprietary.

If my description is no longer accurate, I would appreciate any
corrections you might make. I stopped using the service when my first
bill gave me sticker shock.

Phil

---

From: "Joseph A. Latone" <[email-masked]>
Date: Fri, 7 Jan 2000 08:59:52 -0800

> >ANY public mail list.

> cable and a laptop running Linux.

Just to confirm Phil's observations, I came to the same conclusions,
although I used a different set of tools, and I don't think my
service contract included an NDA.  Joe