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Versions: 00                                                            
Network Working Group                                          T. Suzuki
Internet-Draft                                             Hitachi, Ltd.
Intended status: Informational                              July 6, 2015
Expires: January 7, 2016


   Use-case and Requirements for Multi-domain Operation Plane Change
               draft-suzuki-teas-actn-multidomain-opc-00

Abstract

   This document provides a use-case and requirements that address the
   need for facilitating dynamic change of an operation plane, which
   includes virtually prepared multiple networks and/or data
   transmission paths, from a current operation one to a backup one
   during scheduled maintenance or an emergency such as a network
   disaster.  Specifically, the necessity of interfaces to establish
   consistent end-to-end data transmission paths over multiple domain
   networks is addressed.

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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   This Internet-Draft will expire on January 7, 2016.

Copyright Notice

   Copyright (c) 2015 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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   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must



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   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Problem Statement  . . . . . . . . . . . . . . . . . . . . . .  4
   3.  Use Case . . . . . . . . . . . . . . . . . . . . . . . . . . .  5
   4.  Requirement for Interface of operation plane change system . .  7
     4.1.  Type I: Direct control interface between DNCs  . . . . . .  7
     4.2.  Type II: Indirect control interface through MDNC . . . . .  8
   5.  Security Considerations  . . . . . . . . . . . . . . . . . . . 11
   6.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 12
   7.  Informative References . . . . . . . . . . . . . . . . . . . . 13
   Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 14


































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1.  Introduction

   This draft provides a use case and requirements that address the
   necessity of a dynamic change of an operation plane, which includes
   virtually prepared multiple networks and/or data transmission paths,
   from a current operation one to a backup one through cooperation
   between inter domain networks during scheduled maintenance or an
   emergency such as a network disaster.

   Networks have become indispensable in daily life, as reflected in the
   popularity of cloud services provided by way of networks, such as the
   Internet.  Therefore, highly reliable end-to-end data transmission
   services must be provided.  In addition, even if network facilities
   are extensively damaged due to a natural disaster, data transmission
   services must be promptly restored.  To meet these requirements, a
   highly reliable packet transport network, such as the Multi-Protocol
   Label Switching - Transport Profile (MPLS-TP) network, is needed and
   may be used to transmit data between not only countries but also data
   centers.

   In conventional packet transport network management, a data
   transmission path protection function is used for promptly recovering
   from a small network failure, such as a node or link failure.
   However, the path protection is not always usable in a network
   disaster.  Plenty of data transmission paths are calculated
   sequentially after a network disaster is detected.  As a result, much
   time is needed to calculate all the paths.  In another case, multiple
   path configurations will be changed for maintenance to add, delete,
   and check network resources.  Therefore, a novel network management
   scheme is needed to change plenty of path configurations
   instantaneously from the current operation plane to the backup one.

   Related documents are the ACTN-framework [ACTN-Framework], the
   problem statement [ACTN-Problem] and the requirements
   [ACTN-Requirement].

   Section 2 discusses specific issues on the prompt changing of network
   configurations.  Section 3 describes a use case for an inter-domain
   network management system.  Section 4 prescribes requirements that
   the system needs to satisfy.











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2.  Problem Statement

   There are two major techniques for recovering from network failures:
   protection and restoration.  In protection, a backup data
   transmission path for a current one is calculated and set up before
   network operations are started.  When a data transmission failure is
   detected, a data transmission path is changed from the current path
   to the backup one.  In restoration, the backup path is not physically
   prepared in advance.  When a data transmission failure is detected, a
   new data transmission path is calculated and/or set up.  Then data
   are transmitted through the newly set up data path.

   In a network disaster due to an earthquake, for example, protection
   paths might not be useful for some situations.  When the protection
   paths are not useful, another backup path should be calculated.  If
   there are plenty of current data transmission paths, calculating the
   backup paths takes an enormous amount of time.  In the same way, a
   huge amount of time is needed to calculate and to set up plenty of
   paths for restoration.

   Enhancement of protection is envisaged as a new recovery procedure
   from a network disaster.  Specifically, a concept of a virtual
   operation plane is adopted.  The virtual operation plane includes
   multiple data transmission paths, and so does the current operation
   plane.  In contrast, a recovery operation plane includes multiple
   backup data transmission paths.  In the new recovery procedure,
   multiple backup operation planes are prepared in advance.  When a
   network disaster is detected, the most suitable backup operation
   plane is selected and configurations for recovery are distributed to
   data transmission nodes.

   In addition, a network system must be able to change plenty of path
   configurations instantaneously when it adds or deletes network
   resources or stops using resources to execute maintenance.

   The system explained above can be easily managed if there is only one
   management server.  However, if the network is composed of multiple
   domains and there are multiple management servers, coordinated
   network disaster recovery procedures are not easy to execute.
   Therefore, a cooperative management scheme for recovering from a
   network disaster is needed.










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3.  Use Case

   A target operation plane change system through cooperation of
   multiple domain controller servers is shown in Figure 1.  The whole
   network is composed of multiple domain networks such as domain-A and
   domain-B physical networks.  Each domain has a domain network
   controller server.  In addition, each domain network is composed of
   multiple packet transport nodes.  An end-to-end data transmission
   path is managed through cooperation between domain network controller
   servers.  Each domain network controller server calculates multiple
   current data transmission paths and manages them as one current
   operation plane.  In addition, the controller server calculates
   multiple backup operation planes and controls them in the case of a
   network disaster.

   For example, the domain-A network controller server prepares a backup
   operation plane, plane-A1, on the basis of the assumption of network
   failures or maintenance.  Plane-A1 includes multiple data
   transmission paths or virtual networks.  The domain-B network
   controller server prepares another backup operation plane, plane-B1,
   to connect data transmission paths to plane-A1 of the domain-A
   network.  On the other hand, the domain-B network controller server
   prepares another backup operation plane, plane-B2, on the basis of
   the assumption of other network failures or maintenance.  The
   domain-A network controller server prepares another backup operation
   plane, plane-A2, to connect data transmission paths to plane-B2 of
   the domain-B network.

   When the domain-A network controller server changes the operation
   plane from the current operation one to plane-A1 during the network
   operation, it transmits an identifier of plane-A1 to the domain-B
   network controller server to show a change of the operation plane of
   the domain-A network controller server.  After receiving the
   identifier of plane-A1, the domain-B network controller server
   changes the operation plane from the current one to plane-B1.

   To develop the above-mentioned system, two interfaces must be
   created.  One maintains consistency of the end-to-end data
   transmission paths between domains in the backup operation plane.
   Specifically, this interface needs to transmit information of the
   backup operation planes including multiple data transmission paths
   from one domain network controller server to another.  The other
   domain network controller server can then calculate backup operation
   planes in accordance with the received backup operation plane
   information.  The other interface is used for transmitting the
   identifier to change the operation plane from one domain network
   controller server to another.




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      +--------------------+         +--------------------+
      | Domain-A network   |         | Domain-B network   |
      | controller server  |         | controller server  |
      +---------+----------+         +---------+----------+
                |                              |
                |                              |
   +------------+-------------+    +-----------+--------------+
   |                          |    |                          |
   |  +--------------------+  |    |  +--------------------+  |
   |  | Current            +----------+ Current            |  |
   |  | operation plane    +----------+ operation plane    |  |
   |  | A0                 +----------+ B0                 |  |
   |  +--------------------+  |    |  +--------------------+  |
   |                          |    |                          |
   | ======================== |    | ======================== |
   |                          |    |                          |
   |  +--------------------+  |    |  +--------------------+  |
   |  | Backup             +----------+ Backup             |  |
   |  | operation plane    +----------+ operation plane    |  |
   |  | A1                 +----------+ B1                 |  |
   |  +--------------------+  |    |  +--------------------+  |
   |                          |    |                          |
   |  +--------------------+  |    |  +--------------------+  |
   |  | Backup             +----------+ Backup             |  |
   |  | operation plane    +----------+ operation plane    |  |
   |  | A2                 +----------+ B2                 |  |
   |  +--------------------+  |    |  +--------------------+  |
   |            -             |    |            -             |
   |            -             |    |            -             |
   |            -             |    |            -             |
   |  +--------------------+  |    |  +--------------------+  |
   |  | Backup             +----------+ Backup             |  |
   |  | operation plane    +----------+ operation plane    |  |
   |  | An                 +----------+ Bn                 |  |
   |  +--------------------+  |    |  +--------------------+  |
   |                          |    |                          |
   +--------------------------+    +--------------------------+
     Domain-A physical network       Domain-B physical network



         Figure 1: Example of target operation plane change system









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4.  Requirement for Interface of operation plane change system

   There are two types of control structures.  One is a direct
   communication type between domain network controllers (DNCs) as shown
   in Figure 2.  The other is an indirect communication type through a
   multi-domain network controller (MDNC) as shown in Figure 3.  To
   realize an operation plane change system, the interfaces shown in
   either figure must be defined.

4.1.  Type I: Direct control interface between DNCs

   The interfaces shown in Figure 2 must be prepared to execute
   consistent changing of operation planes to establish end-to-end data
   transmission paths between multiple domain networks for network
   disaster recovery or maintenance.  The requirements for each
   interface are briefly described below.

   (I-1) Interface for preparing backup operation planes:
         This interface is used to prepare consistent backup operation
         planes through cooperation between DNCs.  For example, the
         domain-A network controller (DNC-A) prepares multiple backup
         operation planes as shown in Figure 1 for the current operation
         plane composed of multiple data transmission paths.  A backup
         operation plane is prepared for each assumed network failure or
         maintenance.  The DNC-A transmits "information of sharing paths
         for each link between domain networks" and "the identifier of a
         backup operation plane" to the domain-B network controller
         (DNC-B) when it attempts to change the operation plane to
         recover from a network disaster or to execute maintenance.
         When the DNC-B controller receives them, it prepares a backup
         operation plane for each received DNC-A backup plane to
         establish consistent data transmission paths.  In addition,
         configurations of prepared backup operation planes are stored.

   (I-2) Interface for requesting change of operation plane:
         This interface is used to send a change request of the
         operation plane from the current one to the backup one when a
         DNC detects a network disaster or starts to execute
         maintenance.  For example, when the DNC-A detects a network
         disaster, it determines the most suitable backup operation
         plane and starts management in accordance with the
         configurations of the selected operation plane.  In addition,
         the DNC-A transmits "the identifier of the backup operation
         plane" to the DNC-B to establish consistent end-to-end paths
         when it changes the operation plane.  When the DNC-B receives
         the identifier of the backup operation plane, it changes the
         operation plane from the current one to the backup one
         specified by the received identifier.  In addition, information



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         of the time to change path configurations is exchanged through
         this interface between DNCs.




      +--------------------+ (I-1)I/F  +--------------------+
      | Domain-A network   | (I-2)I/F  | Domain-B network   |
      | controller (DNC-A) |<--------->| controller (DNC-B) |
      +---------+----------+           +---------+----------+
                |                                |
                |                                |
   +------------+-------------+     +------------+-------------+
   |                          +-----+                          |
   |  Domain-A                +-----+  Domain-B                |
   |  physical network        +-----+  physical network        |
   +--------------------------+     +--------------------------+
                               Links



                    Figure 2: Control structure type I

4.2.  Type II: Indirect control interface through MDNC

   In the case of the type II control communication structure, the
   interfaces shown in Figure 3 must be prepared to execute consistent
   changing of operation planes to establish end-to-end data
   transmission paths between multiple domain networks for network
   disaster recovery or maintenance.  The requirements for each
   interface are briefly described below.

   (II-1) Interface to MDNC for preparing backup operation planes:
         This interface is used to prepare consistent backup operation
         planes through cooperation between DNCs through the MDNC.  For
         example, the DNC-A prepares multiple backup operation planes
         for the current operation plane composed of multiple data
         transmission paths.  A backup operation plane is prepared for
         each assumed network failure or maintenance.  The DNC-A
         transmits "information of sharing paths for each link between
         domains" and "the identifier of a backup operation plane" to
         the MDNC in order to send the information to the DNC-B as a
         final destination.

   (II-2) Interface to MDNC for requesting change of operation plane:
         This interface is used to send a change of the operation plane
         from the current one to the backup one when a DNC detects a
         network disaster or starts to execute maintenance.  For



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         example, when the DNC-A detects a network disaster, it
         determines the most suitable backup operation plane and starts
         management in accordance with the configurations of the
         selected operation plane.  In addition, the DNC-A transmits
         "the identifier of the backup operation plane" to the MDNC to
         establish consistent end-to-end paths in order to send the
         identifier to the DNC-B as a final destination.

   (II-3) Interface to DNC for preparing backup operation planes:
         This interface is used to prepare consistent backup operation
         planes by cooperation between DNCs through the MDNC.  For
         example, the MDNC transmits received "information of sharing
         paths for each link between domains" and "the identifier of a
         backup operation plane" to the DNC-B.  When the DNC-B receives
         them, it prepares a backup operation plane for each received
         DNC-A backup plane to establish consistent data transmission
         paths.  In addition, configurations of prepared backup
         operation planes are stored.

   (II-4) Interface to DNC for requesting change of operation plane:
         This interface is used to send a change of the operation plane
         from the current one to the backup one.  For example, the MDNC
         transmits received "the identifier of the backup operation
         plane" to the DNC-B.  When the DNC-B receives the identifier,
         it changes the operation plane from the current one to the
         backup one specified by the received identifier.  In addition,
         information of the time to change path configurations is sent
         through this interface from the MDNC to the DNC-B.























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      +-----------------------------------------------------+
      |       Multi-domain network controller (MDNC)        |
      +------------------------------------------+----------+
                ^                                |
                :(II-1)I/F                       |(II-3)I/F
                :(II-2)I/F                       |(II-4)I/F
                :                                v
      +--------------------+           +--------------------+
      | Domain-A network   |           | Domain-B network   |
      | controller (DNC-A) |           | controller (DNC-B) |
      +---------+----------+           +---------+----------+
                |                                |
                |                                |
   +------------+-------------+     +------------+-------------+
   |                          +-----+                          |
   |  Domain-A                +-----+  Domain-B                |
   |  physical network        +-----+  physical network        |
   +--------------------------+     +--------------------------+
                               Links



                    Figure 3: Control structure type II




























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5.  Security Considerations

   This document describes problems and requirements for network
   disaster recovery or maintenance through cooperation between domain
   management functions or servers.  The system might be composed of
   multiple management functions to manage each domain network, and each
   management function might be implemented in different computational
   equipment.  To achieve network disaster recovery through coordination
   between multiple network domains, information must be exchanged
   between them.  Therefore, a secure communication channel needs to be
   used between the domain management functions.








































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6.  IANA Considerations

   This document includes no request for IANA.
















































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 7.   Informative References

    [ACTN-Framework]
              Ceccarelli, D., Lee, Y., Fang, L., Lopez, D., Belotti,
              S., King, D., and D. Dhoddy, "Framework for Abstraction
              and Control of Transport Networks", June 2015.

              <http://tools.ietf.org/pdf/
              draft-ceccarelli-teas-actn-framework-00>

   [ACTN-Problem]
              Lee, Y., King, D., Boucadair, M., Jing, R., and L.
              Murillo, "Problem Statement for Abstraction and Control of
              Transport Networks", June 2015.

              <http://tools.ietf.org/pdf/
              draft-leeking-teas-actn-problem-statement-00>

   [ACTN-Requirement]
              Lee, Y., Belotti, S., Pithewan, K., and D. Ceccarelli,
              "Requirements for Abstraction and Control of Transport
              Networks", April 2015.

              <https://tools.ietf.org/pdf/
              draft-lee-teas-actn-requirements-00>


























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Author's Address

   Toshiaki Suzuki
   Research & Development Group, Hitachi, Ltd.
   292 Yoshida-cho
   Totsuka-ku, Yokohama, Kanagawa  244-0817
   Japan

   Phone: +81-50-3135-3066
   Email: toshiaki.suzuki.cs@hitachi.com









































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