Network Working Group                                          M. Taylor
Request for Comments: 1674                               CDPD Consortium
Category: Informational                                      August 1994

                    A Cellular Industry View of IPng

Status of this Memo

   This memo provides information for the Internet community.  This memo
   does not specify an Internet standard of any kind.  Distribution of
   this memo is unlimited.


   This memo is a response to RFC 1550, "IP: Next Generation (IPng)
   White Paper Solicitation".  The statements in this paper are intended
   as input to the technical discussions within IETF, and do not
   represent any endorsement or commitment on the part of the cellular
   industry, the Cellular Digital Packet Data (CDPD) consortium of
   service providers or any of its constituent companies.


   This is a draft of the requirements for IPng as envisioned by
   representatives of the Cellular Digital Packet Data (CDPD) consortium
   of service providers.  As the leading service providers for this
   nascent technology, which will provide the capability for mobility of
   native mainstream connectionless network layer-based applications it
   is our intention to support whatever form IPng takes.  However, there
   are several requirements which we feel IPng must meet.


   Since we will offer mobile services, our primary requirement is that
   IPng not inhibit our support of mobility.  IPng must not impede
   devices from being able to operate anywhere anytime.  Applications on
   these mobile devices must look and feel the same to the user
   regardless of location.  NPDUs should be self-contained and not
   disallow the redirection inherent to our mobility solution, i.e.,
   IPng must be connectionless.

   Further, since IPng provides an opportunity for design enhancements
   above and beyond IPv4, we propose that native support for mobility be
   regarded as an explicit IPng requirement.  Local area and wide area
   wireless technology creates new opportunities for both TCP/IP and the
   Internet.  Although the capability for mobility is orthogonal to the
   wired or wireless nature of the data link in use, the rapid

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RFC 1674            A Cellular Industry View of IPng         August 1994

   deployment wireless technology amplifies the requirement for
   topological flexibility.

   As a by-product of mobility, the significance of "occasionally-
   connected hosts" increases.  The ability to accommodate
   occasionally-connected hosts in IPng is a requirement.


   In terms of scale, we envision some 20 to 40 million users by the
   year 2007.  In this context a "user" can be anything from a vending
   machine to a "road warrior".  These numbers are for North America
   alone.  Worldwide, we anticipate that IPng should be able to support
   billions of "users".  Of course, the sparseness of network address
   assignments which is necessary for subnetting, etc., dictates that
   IPng should support at least tens or hundreds of billions of


   In terms of addressing, we would expect addresses to be hierarchical.
   In addition, a node with multiple links should require only a single
   address although more than one address should also be possible.  The
   mapping of names to addresses should be independent of location; an
   address should be an address, not a route.  Variable-length
   addressing is also required to ensure continued protocol (IPng)
   extensibility.  Administration of address assignments should be
   distributed and not centralized as it is now.


   IPng should also support security mechanisms which will grow
   increasingly important on the proverbial "information highway" for
   commercial users.  Security services which may optionally be expected
   from a Layer 3 entity such as IPng include peer entity
   authentication, data confidentiality, traffic flow confidentiality,
   data integrity and location confidentiality.


   The ability to do accounting at Layer 3 is a requirement.  The CDPD
   specification can be used as a model of the type of accounting
   services that we need.

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RFC 1674            A Cellular Industry View of IPng         August 1994

Route Selection

   In the voice communications arena, "equal access" and choice of an
   "interexchange carrier (IXC)" are issues that must be addressed.
   Similar requirements for data may also exist.

   Source- and policy-based routing for inter-domain traffic can address
   this requirement.  IPng must allow the selection of at least the
   first transient network service provider based on the source host.

Data Efficiency

   The bandwidth of wide area wireless networks is a precious resource,
   the use of which must be optimized.  IPng must allow optimal use of
   the underlying Layer 2 medium.  Layer 3 Protocol Control Information
   (PCI) should be as condensed as possible.  The protocol should be
   optimized for data efficiency.

   Packet prioritization must also be supported by IPng in order to
   optimize the use of low speed networks.  This requirement includes
   both class and grade of service definitions for flexibility.


   The final requirement for IPng is that it must interoperate with IP
   for the foreseeable future.  Bridging mechanisms must be supported
   and a strategy for the transition from IPv4 to IPng must be defined.
   Use of options fields, etc., are one mechanism to support the
   requirement for IPng protocols to support IP addresses and headers.

Security Considerations

   See section on Security.

Author's Address

   Mark S. Taylor
   Director of System Development
   McCaw Cellular Communications, Inc.
   Wireless Data Division
   10230 NE Points Drive
   Kirkland, WA 98033-7869 USA


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