Internet Info 1997 December/Internet_Info_CD-ROM_Walnut_Creek_December_1997.iso/ietf/mobileip/mobileip-minutes-93jul.txt

Text File | 1993-09-16 | 15.2 KB | 394 lines

CURRENT_MEETING_REPORT_

Reported by John Johnston/National Semiconductor

Minutes of the IP Routing for Wireless/Mobile Hosts Working Group
(MOBILEIP)


Agenda

   o Review of mobility model
   o Liaison reports
   o Document status
   o Subcommittee reports
   o Short presentations
   o Interim Meeting


Mobility Model

Greg Minshall reviewed the mobility model for the first time attendees
in the session.  Basically, the problem was stated as finding a
methodology (architecture, protocol, etc.)  to support the routing of
mobile hosts (MH). In most of the models presented to date, each MH has
both a home address and a forwarding or care of address.  Packets are
sent to a MH via its home address.  These packets are directed via
normal routing to a base station which serves as the home base of the
MH. This base station must know where the MH is at all times by
maintaining the IP address of the base station currently serving the MH.
Assuming the MH is ``not at home'' the base station then forwards the
packet to its peer currently serving the MH, who in turn delivers the
packet directly to the MH.

The base station to base station delivery mechanism is called tunneling
which can result in inefficient (dogleg) routing.  An extreme example is
a US-based Amsterdam IETF attendee trying to connect to a local
Amsterdam host.  Packets would be first routed over the Atlantic to the
home base station in the US, then routed back over the Atlantic to the
MH's current base station in Amsterdam, and finally delivered to the
local Amsterdam host.  This problem will be handled through the use of
address caching.

Finally, Greg clarified the scope of the working group as supporting
media independent mobility.  One solution must handle wireless IR,
wireless RF, ethernet, etc.


Liaison Reports

Charlie Perkins reported that 802.11 is standardizing IEEE MAC protocols
for wireless media.  This body is meeting during the same week as the
IETF. At their last session, Charlie proposed that the IETF working
group inform 802.11 about all of the network layer events and
indications that will be necessary to support mobile IP. Charlie
indicated that 802.11 still has many open issues including MAC address
selection (48-bit?).

Steve Alexander did not report on the Dynamic Host Configuration Working
Group (DHC) because the group has not met since the last IETF.

Scott Kaplan, the liaison for the Domain Name System Working Group
(DNS), did not report, because he was unable to attend the last DNS
session.

There was no report given for the Internet Protocol Security Protocol
Working Group (IPSEC) because John Ioannidis was unable to attend this
MOBILEIP session.



Document Status

   o Fumio Teraoka from Sony will distribute a new version of his
     document when he returns from the IETF.

   o Dave Johnson has an updated version of his document available.

   o The working group has not heard from Columbia University.

   o Charlie Perkins will complete a new version of his document in
     several months.

   o Matsushita's draft work is continuing.  A version will be released
     in several weeks.



Subcommittee Reports

   o Terminology (Perkins)

        Charlie conveyed the confusion over inconsistent terminology by
        offering the following list:

            Host
            Mobile Host
            Correspondent Host - used to describe a destination host
                                 which may or may not be mobile
            Home Address Agent/Home Redirector (Location Server)
            Location Directory
            Base Station (Cell Manager)
            Visited Redirector/Remote Redirector
            Visitor's Redirector/Vistor's Redirector
            Cell Cluster

        Consistent terminology has not yet been selected.  Consensus was
        that this must happen as soon as possible, but it was recognized
        that we must agree on the functionality of the things we are
        naming before we can agree on their names.  Acronyms should be
        avoided at least until consistent terminology is adopted.

   o Beaconing (Perkins)

        Charlie described beaconing as the method by which a Mobile Host
        advertises itself to a base station.  Some link layers have
        beaconing built-in and will not require layer 3 support.
        Mechanisms must be identified to support advertisement requests
        (solicitation), acceptance, and responses.  Broadcast and
        multicast mechanisms are both under consideration.  Open
        question - Can we use existing router discovery methods?

   o User Requirements (Rehkter)

        Yakov presented an overview of his latest document which will be
        available in several weeks.  This document addresses the
        Internet model, mobile computing models, mobility dynamics,
        overhead considerations, scalability, performance transparency,
        manageability, security, and a comprehensive solution.

   o Database Service Interface (Rehkter) - no report

   o Tunneling/Redirecting (Dave Johnson)

        Tunneling is initiated by a Location Cache or a Location Server
        (Dave's terms).  Dave is no longer supporting loose source
        routing because it is slow, buggy, and politically incorrect.
        Instead, the approach is to use encapsulation as described by
        Dave's latest document.  This approach supports all existing IP
        options, cache coherency through the dynamic maintenance of an
        address forwarding list in each tunneled packet, loop discovery
        through the same address list, and base station state recovery.
        Cache coherency is also supported through a new mobile ICMP
        redirect message.  Open questions are:
            1. Does this break trace route?
            2. Does this break MTU discovery?

   o Security (Ioannidis) - John Ioannidis was unable to attend

   o MIB - not discussed



Short Presentations

   o Dave's Latest Document (Dave Johnson)

        Dave presented the essence of his latest proposal when he
        discussed tunneling/redirecting.  It was decided to table
        further discussions until the WG had a chance to read the new
        version.

   o Review of Existing Mobile Services and Techniques (John Penners)

        John listed existing technologies and services.  He briefly
        described RAM Mobile Data, ARDIS, PRMA (Packet Reservation
        Multiple Access), CDPD (Cellular Digital Packet Data), AMPS
        (Advanced Mobile Phone System), GSM (Groupe Special Mobile), and
        DECT (Digital European Cordless Telecom).  See his document for
        for more details.

   o Experience with CU Mobile Implementation (Jim Binkley)

        Jim described problems encountered while porting the CU code.
        The 20 MHs were DOS based, while the 7 MSRs were ported to UNIX
        and supported mobility on each port.  His results are based on 1
        month of testing.
            - DOS MH implementation difficulties outline the need for
              and MH architecture ASAP.
            - CU requirements = ARP, route, and raw sockets.  Needed
              help from FTP software.
            - A multi-home bug was discovered.  Because forwarding
              address != IP source address, MSRs got into trouble
              looking at addressing in previous layers.
            - intra segment routing needs to be addressed (ARP)
            - problems with traceroute, IP options, and 8k fragmentation
              when using IPIP encapsulation
            - implementation bug in MSR led to infinite ack loops
            - Installation of JI's embedded subnet demonstrated
              importance that home subnet not be in too many (> 4)
              partitions.
            - JI's embedded subnet causes MSRs to burn packets with
              proxy ARP turned on.
            - directed broadcast caused broadcast storms - routers don't
              realize its a broadcast, so it is forwarded.
            - when Jim "unplugged it and watch"ed, PC based NFS crashed
              and BSD NFS/UDP exhibited slow start

   o Beaconing Procedure (Charlie Perkins)

            Charlie outlined a beaconing procedure:

                1. MH solicits to either a known MAC (unicast) or an
                   unknown MAC (broadcast/multicast)
                2. IAP (Internet Access Point) advertises (unicast or
                   broadcast/multicast)
                3. MH sends acceptance (unicast, with encrypted value?)
                4. IAP sends ack or reject
                5. MH updates old IAP
                6. MH updates home redirector

            and proposed a beacon packet format:

                type, code, checksum
                IAP address
                timestamp/serial #
                beacon interval/lifetime
                random value to by encrypted
                MAC address
                type of authentication (including none)

            The status of Charlie's work:
                - intend to try icmp "host moved" function in IAPs
                - intend to release code fragments
                - will switch from simple beacon
                - need to select encapsulation/get protocol #/modify
                  IPIP
                - intend to support public domain Mach implementation
                - desires routing to "shared media"
                - port to OS/2


Interim Meeting


There was consensus to meet somewhere on the east coast sometime before
the November IETF. Possible dates and locations will be discussed via
the mailing list.



Further Discussion


Yakov Rehkter's subcommittee report on user requirements created a
discussion regarding CDPD. This technology was described by Mark
Knopper:


   o Consortium of 9 large US and 1 Canadian voice carriers.
   o Data services over cellular infrastructure.
   o Mobile End System makes itself known to a Mobile Intermediary
     System.
   o Packets routed first to Intermediary System which forwards them to
     End System.
   o Billing through X.400.


Suzy Brown expressed the desire for the IETF to press ahead quickly to
avoid the potential for deployment of technology-specific solutions that
will not interoperate with the Internet.  Other infrastructure-based
solutions are being developed (Ram Mobile Data, Mobitex, GSM, etc.).

Along the same lines, John Penners' review of mobile services spawned
discussions centering on the relationship between mobile IP and the many
specialized services and providers.  Steve Deering presented a model
that emphasized the logical separation from wireless service providers
and the Internet.  This led to several observations:


   o We should view the technologies as physical medium below IP
     (service provider is at lower level).

   o Successful mobile IP deployment could leverage incorporation into
     technology-specific switches.

   o A goal is to avoid ``doglegs.''

   o Single hop at IP level (not single physical hop) in service
     provider.

   o Understanding providers' rules might help the dogleg problem.

   o Service providers need mobile IP to connect their clouds.


Greg Minshall presented a similar model emphasizing how CDPD could
create a coast-to-coast dogleg because it is not care of address-aware.
This led to a discussion over whether it would be beneficial to take
proactive measures to influence CDPD.

During Charlie Perkins' presentation on beaconing procedures, Steve
Deering emphasized the desirability that mobile hosts transmit new base
station updates (as opposed to IAPs).  Also, Steve stated that he would
like to use multicast addressing over broadcast whenever possible
(addressing must be consistent within a cell), and Greg indicated that
we should request a ``well known'' address for this purpose.


Open Issues

   o Can we use existing router discovery methods to support beaconing?
   o Does Dave Johnson's encapsulation technique break traceroute?
   o Does Dave Johnson's encapsulation technique break MTU discovery?


Action Items

   o Steve Deering will contact Columbia University for an update on
     their work.

   o Determine if a working group should be formed within the IETF to
     deal with the issues of encapsulation.

   o Obtain a well known multicast address.

   o Obtain new ICMP number.


Attendees

Kannan Alagappan         [e-mail]
Steve Alexander          [e-mail]
Nick Alfano              [e-mail]
James Allard             [e-mail]
Bernt Allonen            [e-mail]
Michael Anello           [e-mail]
Anders Baardsgaad        [e-mail]
Cynthia Bagwell          [e-mail]
Dennis Baker             [e-mail]
John Ballard             [e-mail]
Nutan Behki              [e-mail]
Per Bilse                [e-mail]
Jim Binkley              [e-mail]
Carsten Bormann          [e-mail]
Michael Brescia
Ronald Broersma          [e-mail]
Ramon Caceres            [e-mail]
Thomas Cordetti          [e-mail]
Geert Jan de Groot       [e-mail]
Stephen Deering          [e-mail]
Pierre Dupont            [e-mail]
Kjeld Borch Egevang      [e-mail]
Julio Escobar            [e-mail]
Dan Frommer              [e-mail]
Shoji Fukutomi           [e-mail]
Robert Gilligan          [e-mail]
Jari Hamalainen          [e-mail]
Mark Handley             [e-mail]
Gerd Holzhauer           [e-mail]
John Hopkins             [e-mail]
Steven Horowitz          [e-mail]
Chris Howard             [e-mail]
Geoff Huston             [e-mail]
David Johnson            [e-mail]
John Johnston            [e-mail]
Philip Jones             [e-mail]
Marijke Kaat             [e-mail]
Scott Kaplan             [e-mail]
Ton Koelman              [e-mail]
Mark Kosters             [e-mail]
Mark Laubach             [e-mail]
Tony Li                  [e-mail]
Susan Lin                [e-mail]
Cynthia Martin           [e-mail]
Donald Merritt           [e-mail]
Paul Milazzo             [e-mail]
Greg Minshall            [e-mail]
William Miskovetz        [e-mail]
Keith Mitchell           [e-mail]
Henri Moelard            [e-mail]
Jun Murai                [e-mail]
Ronny Nilsen             [e-mail]
Petri Ojala              [e-mail]
Zbigniew Opalka          [e-mail]
John Penners             [e-mail]
Charles Perkins          [e-mail]
Jim Rees                 [e-mail]
Yakov Rekhter            [e-mail]
Henry Sanders            [e-mail]
Hal Sandick              [e-mail]
William Simpson          [e-mail]
Fumio Teraoka            [e-mail]
Antoine Trannoy          [e-mail]
Thierry Turletti         [e-mail]
Werner Vogels            [e-mail]
Jost Weinmiller          [e-mail]
Kirk Williams            [e-mail]
Rachel Willmer           [e-mail]
Sam Wilson               [e-mail]
Wilfried Woeber          [e-mail]
Jessica Yu               [e-mail]
Romeo Zwart              [e-mail]