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Internet Engineering Task Force                                 R. Kumar
Internet-Draft                                                 A. Lohiya
Intended status: Informational                          Juniper Networks
Expires: August 2, 2017                                      M. Blanchet
                                                                Viagenie
                                                        January 29, 2017


   Centralized Address Space Management(CASM) Problems and Use cases
               draft-kumar-casm-problem-and-use-cases-00

Abstract

   The organisations use IP Address Space Management (IPAM) tools to
   manage their IP address space, often with proprietary database and
   interfaces.  This document describes evolution of IPAM into a
   standardized interfaces for centralized management of IP addresses.

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
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   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on August 2, 2017.

Copyright Notice

   Copyright (c) 2017 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
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   include Simplified BSD License text as described in Section 4.e of




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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Requirements Language . . . . . . . . . . . . . . . . . . . .   3
   3.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Address Space Management Use cases  . . . . . . . . . . . . .   3
     4.1.  DHCP server pool  . . . . . . . . . . . . . . . . . . . .   3
     4.2.  Static address configuration  . . . . . . . . . . . . . .   3
     4.3.  Public IP address pool  . . . . . . . . . . . . . . . . .   4
     4.4.  Multicast IP address pool . . . . . . . . . . . . . . . .   4
     4.5.  SDN controllers . . . . . . . . . . . . . . . . . . . . .   4
   5.  Legacy address space management (IPAM) systems  . . . . . . .   4
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   5
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   5
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .   5
   9.  Informative References  . . . . . . . . . . . . . . . . . . .   5
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   6

1.  Introduction

   The address space management is an intergral part of any network
   management solution.  The network may be based on legacy design or a
   more modern private and public cloud, the network may be big or small
   but every network operator need to manage the addressing needs of
   network elements.  Typically, network operators write proprietary
   scripts or use cheat sheets to manage the addressing requirements.
   In recent trends, open source communities have developed tools to
   manage available IP addreess space.

   The open source or proprietray tools and scripts are collectively
   known as Internet Protocol Address Management (IPAM) system.  The
   organizations use IPAM system to manage their IP address space, often
   with proprietary database and interfaces.  One of the biggest
   challenges with IPAM systems, is lack of standardized interface for
   allocation, storing and retrieving information.

   This document describes a diverse set of use cases for a IPAM system
   and the probelms identfied with current IPAM approach.  The problems
   identifed here should become the basis for a new vision defined as
   Centralized Address Space Management (CSAM).








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2.  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].

3.  Terminology

   CASM:   Centralized Address Space Management

   IPAM:   IP Address Management

4.  Address Space Management Use cases

   The address space management is an intergral part of any network
   management solution.  Every device in the network be it a physical or
   virtual, needs an IP address for communication with other devices in
   the network.  There is an absolute requirement that a network
   operator must find a way to assign address to these devices.

   The address management could be as simple as having one address pool
   from where addresses are allocated or may a much more complex scheme
   based on various requirements and nature of the network.  This
   section is going to identfiy few top uses cases of address
   management.

4.1.  DHCP server pool

   One of the most common method to assign an IP address to a device or
   function is DHCP.  A device may request one or more IP addresses.
   The DHCP server on network handles all the DHCP requests and assign
   IP addresses.  These addresses are allocated from a pre-defined
   address pool.

   A DHCP server might need multiple address pools if it manages DHCP
   request on multiple network segments.  An address management system
   may be used to initialize these address pools on DHCP servers or
   could also be configured statically.  But the static assigment is
   prone to misconfiguration and if the DHCP server is ever replaced,
   the new server must be configured with the same old pool.

4.2.  Static address configuration

   Some devices or functions do not rely on DHCP protocols to obtain an
   IP address.  This could be due to lack of DHCP client functionality
   or lack of DHCP server avaialable in the network segement for
   whatever reason.  In such situations, an IP address may be configured
   statically but static IP address assignment is prone to errors as



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   mentioned earlier.  The better way is to use an address management
   system for configuring devices without DHCP support.

4.3.  Public IP address pool

   The public IPv4 addresses are very precious resources and should be
   used very carefully.  A given organization may have a small number of
   these addresses, so it must find a way to allocate and free these
   resources effectively.  The manual configuration mechanism may not be
   the best way to manage this resource.

4.4.  Multicast IP address pool

   The multicast addresses are used for distributing broadcast contents.
   The multicast content distributor must be assigned an address and the
   content consumer must somehow figure out that address.  This is
   usually configured manually or throgh proprietary mechanisms.

4.5.  SDN controllers

   In order to build private or public clouds, address management of
   virtual machines, virtual functions and overlay networks is a very
   important task.  In addition, the network operator also need to
   manage addressing of undelay network elements.  The SDN controllers
   and underlay management systems must coordinate addressing schemes to
   ensure smooth operation.  There is need for one address management
   system that would meet the requirements of such a network deployment.

   In order to create overlay networks and virtual workloads, the SDN
   controller also manage MAC addresses to assign to virtual network
   interfaces.  But this is typically not handled by IPAM systems.

5.  Legacy address space management (IPAM) systems

   As mentioned earlier, address management is a central component of
   every network management system.  Organizations small or large deploy
   different ways of achieving this; some write their own scripts or use
   cheat sheets, and others use open source tools.

   These systems may not be suitable for all kind of uses cases due to
   lack of functionality and moreover the interfaces to these systems
   are closed which makes migration from one system to other difficult.

   Although, the functionality of IPAM systems vary from vendor to
   vendor but in general as a whole, following drawbacks exists:

   o  Lack of common set of standard interfaces across IPAM system
      vendors



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   o  Address usually allocated with very little or no context

   o  Lacks ability to annotate requests with user-defined attributes as
      private or public address

   o  Lacks capability to manage both unicast and multicast addresses

   o  MAC address and network segment (VLAN) does not given enough
      information about user or usages

   o  Lack of built-in multi-tetancy into interfaces

   o  Lack of information about address requester such as virtual or
      physical device

   o  Lack of integration with name services such as DNS

   o  Lack of integration with DHCP server to get address records

   o  Lack of integration with address translation services such as
      NAT44 and NAT64

   The purpose is not to show a laudry list of deficiencies in the
   available IPAM system but to show a need to develop a new system that
   can meet the address allocation requirements of modern network
   architectures that gives consumers a portable way to use these
   systems.

6.  Acknowledgements

   This document started from a slide deck authored by Rakesh Kumar and
   Anil Lohiya.

7.  IANA Considerations

   This memo includes no request to IANA.

8.  Security Considerations

   TBD

9.  Informative References

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




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Authors' Addresses

   Rakesh Kumar
   Juniper Networks
   1133 Innovation Way
   Sunnyvale, CA  94089
   US

   Email: rkkumar@juniper.net


   Anil Lohiya
   Juniper Networks
   1133 Innovation Way
   Sunnyvale, CA  94089
   US

   Email: alohiya@juniper.net


   Marc Blanchet
   Viagenie
   246 Aberdeen
   Quebec, QC  G1R 2E1
   Canada

   Email: marc.blanchet@viagenie.ca
   URI:   http://viagenie.ca























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