Subject: Re: [MOBILE-IP] 3g wireless HLR/VLR Issues

From: [email-masked]
Date: Tue, 14 Dec 1999 12:05:19 +0200

Hi,

>In both PN-4286 and 3G TR 23.923
>we continue to see the existence of the location registries of HLR and VLR
and
>SS7 signalling. Only the proposals like Cellular IP and Hawaii do not
contain those
>in their architectures.
>  My question no 1 is if HLR/VLR and SS7 will outlive all IP networks of
future.
>  My question no 2 is both PN-4286 and TR 23.923 talk about FA which
disappears in IPv6,
>so what is the new architecture for Mobile IPv6?

I can only speak for the 3G TR 23.923, because that is what I have worked
with. Our design assumptions when starting that TR was to study the
integration of Mobile IP with the UMTS packet switched infrastructure
without affecting the functionality of the infrastructure itself too much.
This was done to achieve compatibility with networks and mobiles that are
not of the same "Step" of Mobile IP TR, e.g. a Step 3 network would
interwork with a pre-Step 3 network and with non-Mobile IP mobiles. Thus, it
was vital that the HLR and the MAP protocol were kept.

In the 3GPP Release 2000 there is studied the possibility to have the
architecture to run on IP. One of the candidates is to replace the SS7
interfaces with IP based interfaces and run the MAP protocol over IP.

If I have understood this correctly and I believe that somebody mentioned
this already on this mailing list, the Cellular IP and Hawaii proposals are
not meant to replace the current Wide Area Cellular Networks. Thus, the
architectural needs are a bit different as well.

To your second question about the IPv6 with the 3G TR 23.923, it is true
that the FA plays an important role in the TR. The 3GPP TSG SA WG2 Mobile IP
Ad Hoc group, which did that document, did simply not have the time to look
into IPv6 as well. As the work of the group was finished last month, the
group listed this handicap as one of the open issues for further study.

One other thing, I know this is kind of late for the discussion of the
architectural difference between the 3GPP2 defined CDMA2000 and the 3GPP
define UMTS, but I'm going to contribute to that discussion anyway. My
understanding is partly based on the presentation that Tom Hiller did in a
3GPP Mobile IP Ad Hoc meeting in Swindon, England last summer. Based on the
knowledge (or believe) it seems to me that if we try to map the UMTS packet
domain with the CDMA2000 packet domain the CDMA2000 RNN corresponds to the
3GPP NodeB + RNC + SGSN. The CDMA2000 RP tunnelling corresponds to the 3GPP
GTP (GPRS Tunnelling Protocol), and the CDMA2000 PDSN to the 3GPP GGSN. My
opinion is based on the functionality of the nodes.

Cheers,

Jonne.

-------
Jonne Soininen
Nokia

Tel:      +358 9 511 68766
Fax:      +358 9 511 68080
Cellular: +358 40 527 4634
Email:    [email-masked]

>Kind regards,

--
Behcet Sarikaya
Computer Communications Lab.
The University of Aizu
Tsuruga, Ikki-machi, Aizu-wakamatsu City
Fukushima, 965-8580 Japan
Tel. +81-242-37-2559 Fax. +81-242-37-2742
Home page:  http://www.u-aizu.ac.jp/~sarikaya/
email: [email-masked]

---

From: "Andrew T. Campbell" <[email-masked]>
Date: Tue, 14 Dec 1999 09:59:56 -0800

Jonne:

> architectural needs are a bit different as well.

Correct - we say let Mobile IP be the master of the wide area
and the micros do the local (LAN, Campus, Met) area stuff.

Good news to see that SS7 is being killed off. We need
signaling in wireless Internet but not that sort of signaling!

> opinion is based on the functionality of the nodes.

I think tunneling is a broken concept (here) promoting pseudo
connections
in the core and will not do in the longer term to support packet data or
scalability. You are replacing a connection with a
tunneled connection (in case of GPRS). Doesn't that stink?

--
Andrew
http://comet.columbia.edu/~campbell

---

From: Pete McCann <[email-masked]>
Date: Tue, 14 Dec 1999 09:49:34 -0600

"Andrew T. Campbell" <[email-masked]> (ATC) writes:

ATC> Jonne:

>> architectural needs are a bit different as well.

ATC> Correct - we say let Mobile IP be the master of the wide area
ATC> and the micros do the local (LAN, Campus, Met) area stuff.

ATC> Good news to see that SS7 is being killed off. We need
ATC> signaling in wireless Internet but not that sort of signaling!

It's not dead yet!  At least in the near term (Mobile IPv4, FA-located
COA) SS7 or at least ANSI-41 provides valuable link-layer security
features.  Without them all sorts of link-layer spoofing and
eavesdropping attacks would become possible.  Mobile IP was created
with the campus LAN environment in mind, where the trust model among
nodes sharing a common broadcast medium is very different from that in
a WAN.  You might say, "security should be end-to-end anyway" but
that's not always possible for small devices, with low on-air
overhead, and in the timeframe when these networks will be deployed.

You can run ANSI-41 over an IP network if you want but it's still
important to interwork it with SS7.  That's where all the HLR/ACs live
today.

>> opinion is based on the functionality of the nodes.

ATC> I think tunneling is a broken concept (here) promoting pseudo
ATC> connections
ATC> in the core and will not do in the longer term to support packet data or
ATC> scalability. You are replacing a connection with a
ATC> tunneled connection (in case of GPRS). Doesn't that stink?

I agree that these essentially link-specific tunnels (R-P, GTP) should
be kept on the edge of the network as much as possible, and I don't
think it's a good idea to carry these across an Internet.  Eventually
they will be squeezed out as FAs get pushed closer and closer to base
stations.  However, neither should you throw away the link-layer
information you need to properly implement security and VPN access -
the "connection" to an FA (NAS box) should preserve this.  And Mobile
IP tunnels across the Internet will be a fact of life, whether for
providing mobility or access to private networks.  We will need to
architect our networks and QoS mechanisms to deal with these tunnels.

-Pete