ALTO                                                      S. Randriamasy
Internet-Draft                                           Nokia-Bell-labs
Intended status: Experimental                              March 5, 2018
Expires: September 6, 2018


                        ALTO cellular addresses
              draft-randriamasy-alto-cellular-adresses-02

Abstract

   This draft proposes to use the cellular address format composed of
   elements as specified by 3GPP and called ECGI.  ECGI stands for
   E-UTRAN Cell Global Identifier and is used in Public Land Mobile
   Networks based on E-UTRAN.

Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
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   Drafts is at https://datatracker.ietf.org/drafts/current/.

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   This Internet-Draft will expire on September 6, 2018.

Copyright Notice

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   publication of this document.  Please review these documents



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   carefully, as they describe your rights and restrictions with respect
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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Relevant ALTO services and documents  . . . . . . . . . . . .   3
   3.  Cell addresses, ALTO Address types and ALTO Entity Domain
       names . . . . . . . . . . . . . . . . . . . . . . . . . . . .   3
     3.1.  ALTO Address Type for cellular networks . . . . . . . . .   4
     3.2.  ALTO Entity Domain for cellular networks  . . . . . . . .   4
     3.3.  Consistency between ALTO Entity Domain and ALTO Address
           Type  . . . . . . . . . . . . . . . . . . . . . . . . . .   5
   4.  Proposed format for ALTO cell identifiers . . . . . . . . . .   5
     4.1.  Endpoint address canonical string format  . . . . . . . .   5
     4.2.  ALTO Cell Id formats  . . . . . . . . . . . . . . . . . .   5
   5.  Examples  . . . . . . . . . . . . . . . . . . . . . . . . . .   6
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   8.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   7
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   7
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .   7
     9.2.  Informative References  . . . . . . . . . . . . . . . . .   7
   Appendix A.  An Appendix  . . . . . . . . . . . . . . . . . . . .   8
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   8

1.  Introduction

   Cellular networks are present in a number of use cases investigated
   in the ALTO WG and it is useful to specify a format for Cellular
   addresses.  In these cases, Endpoints, PIDs and entities may be
   cells.  In order to specify services such as Network Maps, Cost Maps,
   Endpoint property or Property Maps, it is necessary to order to
   specify an ALTO format for Cell addresses.

   For the sake of efficiency, a preferred option is to use the cell
   identifier format as specified by 3GPP [TS 36.300] and called ECGI,
   as already proposed in [draft-rauschenbach-alto-wireless-access-00]
   and in other discussions.  ECGI stands for E-UTRAN Cell Global
   Identifier and is used in Public Land Mobile Networks based on
   E-UTRAN, see [TS 36.331].

   The purpose of this document is to be completed by the ALTO WG and in
   particular:




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   - Amend and finalize the specification for the ALTO Cell identifier
   format proposed in the present version,

   - define a placeholder for this specification, identify related ALTO
   features and ALTO WG documents.

2.  Relevant ALTO services and documents

   Particular services and drafts where an ALTO address type for
   cellular networks is needed include:

   o  - Endpoint property service: extended to allow endpoints to be
      cells on which properties can be requested,

   o  - (Filtered) Cost Map Service: where PIDs can be cells within and
      among which cost values can be requested, see also[draft-
      randriamasy-alto-cost-context-01],

   o  - "Mobility Network Models in ALTO" defined in [draft-bertz-alto-
      mobilitynets] propose to identify network points of attachment
      (PoA) such as cells to PIDs.

   o  - "ALTO Performance Cost Metrics": being defined in [draft-ietf-
      alto-performance-metrics-01], they will be extended to performance
      costs in cellular networks,

   o  - "Extensible Property Maps for the ALTO Protocol", being defined
      in [draft-ietf-alto-unified-props-new] are applicable to entities
      that may be cells which are identified by their addresses.  In
      this document a domain identifier for cells will need to be
      accordingly defined, and the entity domain identifier "ecgi" is
      proposed.

3.  Cell addresses, ALTO Address types and ALTO Entity Domain names

   This section reflects ALTO WG discussions.  The ALTO Address Type
   Registry is detailed in Section 14.4 of RFC7285 specifying the base
   ALTO protocol.  It currently lists ALTO address types "ipv4" and
   "ipv6".  These ALTO address types can be used in the Endpoint
   Property Service and the Endpoint Cost Service.  They can also be
   used to list the endpoints covered by a PID.  The ALTO base protocol
   however does not preclude other address types, See RFC7285, section 
   2.2 Endpoint Address.

   The draft [draft-ietf-alto-unified-props-new] introduces and
   specifies two new information services called Property Map and
   Filtered Property Maps.  They specify two media types, called "alto-
   propmap+json" and "alto-propmapparams+json".  A Property Map exposes



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   values of properties that are defined on Entities, where an Entity is
   an object that extends the scope of an Endpoint having an individual
   IP address to groups of Endpoints, PIDs, network elements abstracted
   from one or more network elements of arbitrary nature.  An Entity has
   a unique address or name and is defined as belonging to a Domain that
   has a unique identifier.  To this end,
   [draft-ietf-alto-unified-props-new] specifies an Entity Domain
   Registry.  An entity can thus potentially be a cell.

   Example entities are Endpoints with addresses in the ipv4 or ipv6
   domain, or PIDs with a name in the "pid" domain.

   The draft points out that that "Entity domains and property names are
   extensible.  New domains can be defined without revising the messages
   defined in this document, in the same way that new cost metrics and
   new endpoint properties can be defined without revising the messages
   defined by the ALTO protocol."

   As a consequence, RFC7285 and draft
   [draft-ietf-alto-unified-props-new] provide the background to allow
   Endpoints and Entities to be cells with well-specified addresses.

3.1.  ALTO Address Type for cellular networks

   Registering cellular addresses in the ALTO Address Type Registry
   allows conveying Endpoint Costs and Properties and (Filtered) Cost
   Maps with PIDs and Endpoints being cells.

   RFC7285 specifies endpoint address formats for ipv4 and ipv6 and the
   purpose of this draft is to agree on a format for cellular endpoints.
   When a cell is mapped to a PID, say "MyCell3" the ALTO Cell Id will
   be used to specify the endpoints within this PID.

   Whereas IP addresses are associated to domains ipv4 and ipv6, a Cell
   Id will be associated to the domain "ecgi".

   The domain name "ecgi" stems from the term ECGI -- E-UTRAN Cell
   Global Identifier, defined in 3GPP.

3.2.  ALTO Entity Domain for cellular networks

   Applications may want to query (Filtered) Property Maps on Cellular
   Networks or on networks comprising cells.  In which case cells would
   have to be identified as Entities with an entity address specific to
   a domain registered in ALTO Entity Domain specified in
   [draft-ietf-alto-unified-props-new].

   The domain "ecgi" is suitable for Entities as well.



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3.3.  Consistency between ALTO Entity Domain and ALTO Address Type

   Actually, the cell address format proposed in section Section 4 is
   suitable for both Endpoints and Entities.  Likewise, ipv4 and ipv6
   addresses.  Whereas cellular and IP Endpoint addresses can also be
   Entity addresses, an Entity is not necessarily an Endpoint.  This is
   the case for instance for entities like PIDs or ANEs.  Therefore
   there is a consistency issue to be solved, and this is done in the
   ALTO Entity Domain specification of the draft
   [draft-ietf-alto-unified-props-new].

4.  Proposed format for ALTO cell identifiers

4.1.  Endpoint address canonical string format

   'ecgi:' MCC '.' MNC ':' ECI

   Where:

   o  MCC: Mobile Country Code, as assigned by ITU.  A 3 digits decimal
      number without leading zeros.

   o  MNC: Mobile Network Code, as assigned by National Authority.  A
      2-3 digits decimal number without leading zeros.

   o  ECI: E-UTRAN Cell Identifier.  A 7 digits lower-case hexadecimal
      number.

   Example:

   o  ecgi:940.978:1234abc

      *  MCC value 940 stands for country or geographical area
         "Wonderland"

      *  MNC value 978 stands for Network N1 in Wonderland and other
         networks in other countries

      *  A same MNC value, say 020 may be associated with several MCCs.

      *  Some MCCs have MNCs encoded with 2 digits and MNCs encoded with
         3 digits.

4.2.  ALTO Cell Id formats

   Three formats are proposed:

   o  'ecgi:' MCC



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   o  'ecgi': MCC '.'  MNC

   o  'ecgi:' MCC '.'  MNC ':' ECI-MASK '/' MASK-LEN

   where:
        MASK-LEN is a decimal number.
        ECI-MASK is a string of lower-case hex digits, of which
                 all but the first MASK-LEN bits are zero.

   Prefix ecgi:P-MCC.P-MNC:P-ECI/N matches ecgi:MCC.MNC:ECI iff
        MCC == P-MCC, and
        MNC == P-MNC, and
        ECI has the same number of hex digits as P-ECI, and
        the first N bits of ECI match those of P-ECI.

5.  Examples

   o  ecgi:940

      *  Matches every cell address with MCC 940.

   o  ecgi:940.978

      *  Matches every cell address with MCC 940 and MNC 978.

   o  ecgi:940.978:1234800/18

      *  Matches every cell address with MCC 940, MNC 978, and a 7-digit
         ECI that starts with the 18 bits 0x12348.  Thus it matches
         ecgi:940.978:1234abc and ecgi:940.978:1234800, but does not
         match ecgi:940.978:1234d00.

6.  IANA Considerations

   This document extends: the ALTO Address Type Registry defined in
   section 14.4 of RFC7285 and the ALTO Domain Entity Registry defined
   in [draft-ietf-alto-unified-props-new].  If the latter is considered
   a superset of the former, it seems consistent to register only a new
   Entity Domain named "ecgi".  This requires that implementations not
   willing to use the (Filtered) Property Map Service and related
   Entities should still be cognizant of the ALTO Domain Entity
   Registry.  Potential extensions are as as follows:

   o  The ALTO Address Type Registry defined in section 14.4 has an
      additional item with the following properties:

      *  Identifier : ecgi




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      *  Address encoding: see section Section 4

      *  Prefix encoding: TBC

      *  Mapping to/from IPv4/v6: none

   o  The ALTO Domain Entity Registry has an additional element with the
      following properties:

      *  Identifier : ecgi

      *  Entity Address encoding: see section Section 4

      *  Field to be updated as [draft-ietf-alto-unified-props-new]
         progresses: indicating that this entity domain can also be used
         as an ALTO Address Type

      *  Hierarchy and inheritance: TBC

7.  Security Considerations

   TBC

8.  Acknowledgements

   Great thanks to Wendy Roome who initiated this document and Qin Wu
   for discussions.

9.  References

9.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

9.2.  Informative References

   [draft-ietf-alto-unified-props-new]
              Roome, W., Chen, S., Randriamasy, S., Yang, Y., and J.
              Zhang, "Extensible Property Maps for the ALTO Protocol",
              March 2018.

   [draft-roome-alto-unified-props-new-00]
              Roome, W. and Y. Yang, "Extensible Property Maps for the
              ALTO Protocol", March 2017.




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Appendix A.  An Appendix

Author's Address

   Sabine Randriamasy
   Nokia-Bell-labs
   Route de Villejust
   Nozay  91460
   FRANCE

   Email: Sabine.Randriamasy@nokia-bell-labs.com








































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