Network Working Group                             Dimitris Zisiadis
Internet-Draft                                      Spyros Kopsidas
Intended status: Experimental Track                   Matina Tsavli
Expires: August 20, 2010                          Leandros Tassiulas
                                                              CERTH
                                            Chrysostomos Tziouvaras
                                                              GRNET
                                                 Guillaume Cessieux                
                                                     Xavier Jeannin 
                                                               CNRS
                                                 February 16, 2010 

             The Network Trouble Ticket Data Model

                 draft-dzis-nwg-nttdm-02.txt


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Copyright Notice

   Copyright (c) 2009 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
   Provisions Relating to IETF Documents in effect on the date of
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Abstract


   Handling multiple sets of network trouble tickets (TTs) 
   originating from different participants inter-connected network
   environments poses a series of challenges for the involved 
   institutions, Grid is a good example of such multi-domain project.
   Each of the participants follows different procedures for handling 
   trouble in its domain, according to the local technical and 
   linguistic profile. The TT systems of the participants collect, 
   represent and disseminate TT information in different formats. 
   As a result, management of the daily workload by a central Network
   Operations Centre (NOC) is a challenge on its own. Normalization 
   of TTs to a common format for presentation and storing at the 
   central NOC is mandatory. In the present document we provide a 
   model for automating the collection and normalization of the TT 
   received by multiple networks forming the Grid. Each of the 
   participants is using its home TT system within its domain for 
   handling trouble incidents, whereas the central NOC is gathering 
   the tickets in the normalized format for repository and handling. 
   XML is used as the common representation language. The model was 
   defined and used as part of the networking support activity of 
   the EGEE project (Enabling Grids for E-sciencE).


Table of Contents

   1.  Introduction ............................................. 4
     1.1. Terminology ........................................... 5
     1.2. Notations ............................................. 5
     1.3. About the Network Trouble Ticket Data Model ........... 6
     1.4. About the Network Trouble Ticket Implementation ....... 6
   2.  NTTDM Types and Definitions .............................. 7
     

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     2.1 Types and Definitions for the TYPE Attributes .......... 7
       2.1.1 Defined ............................................ 7
       2.1.2 Free ............................................... 7
       2.1.3 Multiple ........................................... 7
       2.1.4 List ............................................... 7
     2.2 Types and Definitions for the VALID FORMAT Attributes .. 8
       2.2.1 Predefined String .................................. 8
         2.2.1.1 Definitions of the Predefined Values ........... 9
       2.2.2 String ............................................ 12
       2.2.3 Datetime .......................................... 12
   3.  NTTDM ................................................... 12
     3.1 NTTDM components ...................................... 12
       3.1.1 NTTDM Attributes .................................. 12
     3.2 NTTDM Aggregate classes  .............................. 13
       3.2.1 NTTDM-Document class .............................. 13
       3.2.2 Ticket class ...................................... 13
       3.2.3 Ticket origin information ......................... 15
         3.2.3.1 PARTNER_ID .................................... 15
         3.2.3.2 ORIGINAL_ID ................................... 15
       3.2.4 Ticket information ................................ 16
         3.2.4.1 TT_ID ......................................... 16
         3.2.4.2 TT_TITLE ...................................... 16
         3.2.4.3 TT_TYPE ....................................... 17
         3.2.4.4 TT_PRIORITY ................................... 17
         3.2.4.5 TT_STATUS ..................................... 18
         3.2.4.6 TT_SOURCE ..................................... 18
         3.2.4.7 TT_OPEN_DATETIME .............................. 19
         3.2.4.8 TT_CLOSE_DATETIME ............................. 19
       3.2.5 Trouble details ................................... 20
         3.2.5.1 TT_SHORT_DESCRIPTION .......................... 20
         3.2.5.2 TT_LONG_DESCRIPTION ........................... 20
         3.2.5.3 TYPE .......................................... 21
         3.2.5.4 TT_IMPACT_ASSESSMENT .......................... 21
         3.2.5.5 START_DATETIME ................................ 22
         3.2.5.6 DETECT_DATETIME ............................... 22
         3.2.5.7 REPORT_DATETIME ............................... 23
         3.2.5.8 END_DATETIME .................................. 23
         3.2.5.9 TT_LAST_UPDATE_TIME ........................... 24
         3.2.5.10 TIME_WINDOW_START ............................ 24
         3.2.5.11 TIME_WINDOW_END .............................. 25
         3.2.5.12 WORK_PLAN_START_DATETIME ..................... 25
         3.2.5.13 WORK_PLAN_END_DATETIME ....................... 26
       3.2.6 Related data ...................................... 26
         3.2.6.1 RELATED_EXTERNAL_TICKETS ...................... 26
         3.2.6.2 ADDITIONAL_DATA ............................... 27
         3.2.6.3 RELATED_ACTIVITY .............................. 26
         3.2.6.4 HISTORY ....................................... 28

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       3.2.7 Localization and impact ........................... 28
         3.2.7.1 AFFECTED_COMMUNITY ............................ 28
         3.2.7.2 AFFECTED_SERVICE .............................. 29
         3.2.7.3 LOCATION ...................................... 29
         3.2.7.4 NETWORK_NODE .................................. 30
         3.2.7.5 NETWORK_LINK_CIRCUIT .......................... 30
         3.2.7.6 END_LINE_LOCATION_A ........................... 31
         3.2.7.7 END_LINE_LOCATION_B ........................... 31
       3.2.8 Contact information ............................... 32
         3.2.8.1 OPEN_ENGINEER ................................. 32
         3.2.8.2 CONTACT_ENGINEERS ............................. 32
         3.2.8.3 CLOSE_ENGINEER ................................ 33
       3.2.9 Security .......................................... 33
         3.2.9.1 HASH .......................................... 33
     3.3 NTTDM Representation .................................. 33
   4.  Internationalization Issues ............................. 35
   5.  Examples ................................................ 35
     5.1 Link Failure .......................................... 35
   6.  Sample Implementation: XML Schema ....................... 36
   7.  Security Considerations ................................. 58
   8.  Acknowledgements ........................................ 58
   9. IANA Considerations ...................................... 59
   10.  List of Acronyms ....................................... 59
   11.  References ............................................. 60
   12.  Authors' Addresses ..................................... 61

   

   



















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1.  Introduction

   Modern telecommunications networks are aimed to provide a
   plethora of differentiated services to theirs customers.
   Networks are becoming more sophisticated by the day, while
   their offering spans a wide variety of customer types and
   services. Quality of Service (QoS) [2] and Service Level 
   Agreement (SLA) [3] provisioning are fundamental ingredients.
   Multiple interconnected institutions spread over different
   countries, targeting a common approach to service offering,
   along with a unified network operation scheme to support these
   services, form Grid networks. Network Management is crucial for
   the success of the Grid. Problem impact assessment, reporting,
   identification and handling as well as trouble information
   dissemination and delegation of authority are some of the main
   tasks that have to be implemented by the members of the Grid.
   The current work evolved within the specific Service Activity 2
   (SA2 - network support) of the European funded EGEE [1] project.
   A central NOC, called the ENOC (EGEE Network Operating Centre) [4]
   is responsible for collecting and handling multiple network TTs
   received by the participating network providers' TT systems.
   Different TT systems are used by each of them, delivering TTs
   in alternate formats, while TT load is growing proportionally
   with the network size and the serviced users. TT normalization,
   i.e. transformation to a common format that is "reasonable" for
   all parties and copes with service demands in a dynamic and
   effective way, is of crucial importance for successful
   management of the Grid.
   In the present work we define a data model for TT normalization
   initially targeted for networking providers serving EGEE. The
   model is designed in accordance with RFC 1297 [11] and the 
   specific needs of the participants, meeting requirements of the 
   multiple TT systems used. It is both effective and comprehensive, 
   as it compensates for the core activities of the NOCs. It is also 
   dynamic as it allows other options to be included in the future, 
   according to demand. It provides an XML representation for conveying
   incident information across administrative domains between
   parties that have an operational responsibility of remediation
   or a watch-and-warning over a defined constituency.  The data
   model encodes information about hosts, networks, and the
   services running on these systems; attack methodology and
   associated forensic evidence; impact of the activity; and
   limited approaches for documenting workflow.





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   The Network Trouble Ticket Data Model (NTTDM) aims to simplify
   TT exchange within the boundaries of a Grid and to enhance the
   functional cooperation of every Network operation Centre (NOC)
   and the Grid Operation Centre (GOC). Community adoption of the 
   NTTDM enhances trouble resolution within the grid framework 
   and imparts network status cognisance by modelling collaboration 
   and information exchange among the operators. The NTTDM definition 
   provides:

   o  A common format that allows GOC as well as all participating
      NOCs to store, exchange, manage and analyze TTs (assessment
      of TT impact).

   o  Increased automation in handling a TT since the network
      operators have a common view to the trouble.

   The model was designed and used as part of the networking
   support activity of the EGEE project.

1.1. Terminology

   NTTDM uses specific keywords to describe the various data
   components. These keywords are: 
   Defined, Free, Multiple, List, Predefined String, String, 
   Datetime, Solved, Cancelled, Inactive, Superseded, 
   Opened/Closed, Operational, Informational, Administrative, 
   Test. 

   Those in this document are to be interpreted as described 
   in Section 2.

1.2. Notations

   The NTTDM is specified in two ways, as an abstract data model
   and as an XML Schema. Section 3 provides a Unified Modeling
   Language (UML) [5] model describing the individual classes and
   their relationship with each other.   The semantics of each
   class are discussed and their attributes explained. In Section
   6, this UML model is converted in an XML Schema [6, 7, 8, 9].
   A specific namespace [10] is also defined.

   The term "XML document" refers to any instance of an XML
   document.   The term "NTTDM document" refers to specific
   elements and attributes of the NTTDM schema.   Finally, the
   terms "class", and "element" will be used interchangeably to
   reference either a given UML class in the data model or its
   corresponding schema implementation.

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1.3. About the Network Trouble Ticket Data Model

   The NTTDM is a data representation that provides a framework
   for normalizing and sharing information among network operators
   and the GOC regarding troubles within the Grid boundaries.
   There has been a lot of thought processing during the design of
   the data model:

   o  The data model serves as a common storage and exchange
      format.

   o  Every NOC still uses its home TT system for network
      management within its area of control.

   o  As there is no universally adopted definition for a trouble,
      in the NTTDM definition the term is used with a comprehensive
      meaning to cover all NOCs.

   o  Handling every possible definition of a trouble incident
      would call for an extremely expanded and complex data model.
      Therefore, the NTTDM purpose is to serve as the basis to
      normalize and exchange TTs. It is flexible and expressive in
      order to ensure that specific NOC requirements are met.
      Specific NOC information is kept outside the NTTDM and
      external databases can be used to feed it.

   o  The domain of managing the information is not fully
      standardized and must rely on free-form textual descriptions.
      The NTTDM attempts to strike a balance between supporting
      this free-form content, while still allowing automated
      processing of incident information.

   The NTTDM is only one of feasible TT data representations. The
   goal of this design was to be as effective and comprehensive to
   cover for the management of a general grid environment.   The
   already used TT formats influenced the design of the NTTDM.

1.4. About the Network Trouble Ticket Implementation

   Here we describe an example of typical use case.
   The Grid project EGEE manages its infrastructure as network
   overlay over the European NRENs and want to be able to warn
   EGEE sites of the unavailability of the network. Thanks to
   collaboration with its network provider the EGEE NOC receive
   TTs (800 tickets/month, 2500 emails/month) from 20 NRENs and
   should be able to cope with the heavy TT process. Thanks to 
   the NTTDM the EGEE NOC can automate the TT workflow:

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   o  TT is filtered, sorted and stored in local DB.

   o  TT impact on the Grid is assessed.

   o  TT is pushed to dashboard and other tools (EGEE TT system,
      statistics, etc.)

2.  NTTDM Types and Definitions

   The various data elements of the TT data model are typed.  This
   section discusses these data types.  When possible, native
   Schema data types were adopted, but for more complicated
   formats, regular expressions or external standards were used.

2.1 Types and Definitions for the TYPE attributes

   These types are used to describe the TYPE attributes.

2.1.1 Defined

   The Defined data type means that the data model provides a mean
   to compute this value from the rest of the fields.

   The Defined data type is implemented as a "Defined" in the
   schema.

2.1.2 Free

   The Free data type means that the value can be freely chosen.

   All Free string should have as an attribute the language used.

   The Free data type is implemented as a "Free" in the schema.

2.1.3 Multiple

   The Multiple data type consists of one value among multiple
   fixed values.
 
   The Multiple data type is implemented as an "Multiple" in the
   schema.

2.1.4 List

   List means many values among multiple fixed values.
   The List data type is implemented as a "List" in the schema.


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2.2 Types and Definitions for the VALID FORMAT attributes

2.2.1 Predefined String

   A Predefined String means the different values are predefined
   in the data model.

   Each field that requires a Predefined String contains a
   specific value. Here is the table that shows the allowed values
   for such fields.

   +------------------------+-----------------------------------+
   |         FIELD NAME     |              VALUES               |
   + -----------------------+-----------------------------------+
   |          TT_TYPE       |    Operational, Informational,    |
   |                        |       Administrative, Test        |
   +------------------------+-----------------------------------+
   |            TYPE        |      Scheduled, Unscheduled       |
   +------------------------+-----------------------------------+
   |        TT_PRIORITY     |         Low, Medium, High         |
   +------------------------+-----------------------------------+
   |  TT_SHORT_DESCRIPTION  |  Core Line Fault, Access Line     | 
   |                        |  Fault, Degraded Service, Router  |
   |                        |  Hardware Fault, Router Software  |
   |                        | Fault, Routing Problem, Undefined |
   |                        |   Problem, Network congestion,    |
   |                        | Client Upgrade, IPv6, QoS, VoIP,  |
   |                        |               Other               |
   +------------------------+-----------------------------------+  
   | TT_IMPACT_ASSESSMENT   |  No impact, Reduced redundancy,   |
   |                        | Minor performance impact, Severe  |
   |                        |      performance impact,          |
   |                        |   No connectivity, On backup,     |
   |                        |       At risk, Unknown            |
   +------------------------+-----------------------------------+
   |        TT_STATUS       | Opened, Updated, Closed, Solved,  |
   |                        |  Inactive, Cancelled, Reopened,   |
   |                        |             Superseded            |
   +------------------------+-----------------------------------+
   |       TT_SOURCE        |  Users, Monitoring, Other NOC     |
   +------------------------+-----------------------------------+

          Figure 1: The allowed Predefined String values

   The Predefined String data type is implemented as an
   "xs:string" in the schema with a sequence of enumerations for
   the allowed values.

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2.2.1.1 Definitions of the Predefined Values

   TT_TYPE
     o  Operational: for network incident & maintenance only.

     o  Informational: Information about the TT system or the
        exchange interface (maintenance, upgrade).

     o  Administrative: Information about the access to the TTS
        (credentials) or the exchange interface.

     o  Test: to test the TT system or the exchange interface, etc.

   TYPE
     o  Scheduled: the incident was scheduled to happen.

     o  Unscheduled: the incident was unscheduled.

   TT_PRIORITY
     o  Low: the TT priority is low.

     o  Medium: the TT priority is medium.

     o  High: the TT priority is high.

   TT_SHORT_DESCRIPTION
     o  Core Line Fault: malfunction of a high bandwidth Core line.

     o  Access Line Fault: malfunction of a medium bandwidth Access line.

     o  Degraded Service.

     o  Router Hardware Fault: malfunction of the router hardware.

     o  Router Software Fault: malfunction of the router software.

     o  Routing Problem: incident regarding the routing service.

     o  Undefined Problem: the nature of the problem is not
        identified.

     o  Network congestion: problem due to traffic at the network
        (blocked).

     o  Client Upgrade: incidents regarding clients/services upgrade.

     o  IPv6: incident regarding the IPv6 network.

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     o  QoS: incident regarding the QoS of the network.

     o  VoIP: incident regarding VoIP.

     o  Other: non listed incident.

   TT_IMPACT_ASSESSMENT
     o  No impact: the incident does not cause any impacts.

     o  Reduced redundancy: the incident produces reduction at the
        redundancy.

     o  Minor performance impact: the incident causes a minor
        performance impact.

     o  Severe performance impact: the incident causes a severe
        performance impact.

     o  No connectivity: the incident causes failure of connectivity.

     o  On backup: the incident produces malfunction on backup services.

     o  At risk: the incident should not have any impact but possibly 
        it may cause some trouble.

     o  Unknown: the nature of the impact is not identified.

   TT_STATUS
     o  Opened: the ticket is opened.

     o  Closed: the ticket is closed.

     o  Updated: the ticket's contents have been updated.
   
     o  Cancelled: the ticket has been opened twice, one of the both
        tickets is cancelled and a relation is done between them via
        RELATED_ACTIVITY.

     o  Solved: the incident is solved but the team prefers to
        monitor for check.

     o  Opened/closed stands for tickets that are opened only to
        report an incident that is already solved.

     o  Inactive: the ticket is under the responsibility of an
        external domain and is no more under the domain control.


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     o  Reopened: the ticket was closed by error, or the problem
        was faulty declared solved. Historical data are very important 
        at this case. 

     o  Superseded: the ticket has been superseded by another one
        (case of a bigger problem having raised many tickets and
        being merged in one single incident). The RELATED_ACTIVITY
        field should include the master ticket reference.

   Allowed transitions for TT_STATUS are only those following.
   Possible final states are indicated with (X).
  
                           +------------------+
                           | Opened/Closed (X)|
                           +------------------+
                                    |
                                    |
                                    V
                             +--------------+
     /-----------------------|  Reopened    |<-------------------\
     |                       |              |---------\          |
     |                       +--------------+          |         |
     |                             ^                   |         |
     |                             |                   |         |
     |                             V                   |         |
     |                     +-------------------+       |         |
     |                     | Superseded    (X) |       |         |
     |                     | or Inactive   (X) |       |         |
     |  /----------------->| or Cancelled  (X) |<---\  |         |
     |  |                  +-------------------+    |  |         |
     |  |                          ^                |  |         |
     |  |                          |                |  V         |
     |  |            +--------+    |            +--------+       |
     |  |  /---------| Opened |---/             | Solved |-----\ |
     |  |  |         |        |---------------->|        |     | |
     |  |  |         +--------+                 +--------+     | |
     |  |  |             |                          ^          | |
     V  |  V             |                          |          | |
   +---------+           |                          |          | |
   |         |----------(|)-------------------------/          V V
   | Updated |           |                              +------------+
   |         |----------(|)---------------------------->|            |
   +---------+           |                              | Closed (X) |
                         \----------------------------->|            |
                                                        +------------+

                 Figure 2: TT_STATUS transition diagram

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2.2.2 String

   The String value is defined by the user of the model.
   The String data type is implemented as an "xs:string" in the
   schema.

2.2.3 Datetime

   Date-time strings are represented by the Datetime data type.
   Each date-time string identifies a particular instant in time;
   ranges are not supported.
   Date-time strings are formatted according to a subset of ISO
   8601: 2000 documented in RFC 3339.

   The Datetime data type is implemented as an "xs:dateTime" in
   the schema.

3. NTTDM

   In this section, the individual components of NTTDM will be
   discussed  in   detail.  This  class  provides  a  standardized
   representation for commonly exchanged Field Name data.

3.1 NTTDM Components

3.1.1 NTTDM Attributes

   The Field Name class has four attributes. Each attribute
   provides information about a Field Name instance. The
   attributes that characterize one instance constitute all the
   information required to form the data model.

   DESCRIPTION

     This field contains a short description of the field name.

   TYPE

     The TYPE attribute contains information about the type of
     the field name it depends on. The values that it may contain
     are: Defined, Free, Multiple, List.

   VALID FORMAT

     This attribute contains information about the format of each
     field. The values that it may contain are: PREDEFINED
     STRING, STRING, DATETIME.

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   MANDATORY

     This attribute indicates if the information of each field is
     required or is optional. In case the information is required
     the field MANDATORY contains the word: "YES". On the
     contrary, when filling the information is optional, the
     field MANDATORY contains the word "NO".

3.2 NTTDM Aggregate Classes

3.2.1 NTTDM-Document class

   The NTTDM-Document class is the top-level class in NTTDM. All
   NTTDM documents are an instance of this class.

   +---------------+
   | NTTDM-Document|
   +---------------+
   | version       |<>--{1..*}--[ Ticket     ]
   | lang          |
   +---------------+

                     Figure 3: NTTDM-Document class

   The aggregate class that constitute NTTDM-Document is:

   Ticket
     One or more. The information related to a single ticket.

   The NTTDM-Document class has two attributes:

   version
     STRING. The value of this attribute MUST be "1.00"

     lang
       Required.

3.2.2 Ticket class

   Every ticket is represented by an instance of the Ticket class.
   This class provides a standardized representation for commonly
   exchanged TT data.






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   +---------+
   | Ticket  |
   +---------+
   |  lang   |<>----------[ Partner_ID               ]
   |         |<>----------[ Original_ID              ]
   |         |<>----------[ TT_ID                    ]
   |         |<>----------[ TT_Open_Datetime         ]
   |         |<>----------[ TT_Close_Datetime        ]
   |         |<>----------[ Start_Datetime           ]
   |         |<>--{0..1}--[ Detect_Datetime          ]
   |         |<>--{0..1}--[ Report_Datetime          ]
   |         |<>----------[ End_Datetime             ]
   |         |<>----------[ TT_Last_Update_Time      ]
   |         |<>--{0..1}--[ Time_Window_Start        ]
   |         |<>--{0..1}--[ Time_Window_End          ]
   |         |<>--{0..1}--[ Work_Plan_Start_Datetime ]
   |         |<>--{0..1}--[ Work_Plan_End_Datetime   ]
   |         |<>----------[ TT_Title                 ]
   |         |<>----------[ TT_Short_Description     ]
   |         |<>--{0..1}--[ TT_Long_Description      ]
   |         |<>----------[ Type                     ]
   |         |<>----------[ TT_Type                  ]
   |         |<>----------[ TT_Impact_Assessment     ]
   |         |<>--{0..1}--[ Related_External_Tickets ]
   |         |<>----------[ Location                 ]
   |         |<>--{0..1}--[ Network_Node             ]
   |         |<>--{0..1}--[ Network_Link_Circuit     ]
   |         |<>--{0..1}--[ End_Line_Location_A      ]
   |         |<>--{0..1}--[ End_Line_Location_B      ]
   |         |<>--{0..1}--[ Open_Engineer            ]
   |         |<>--{0..1}--[ Contact_Engineers        ]
   |         |<>--{0..1}--[ Close_Engineer           ]
   |         |<>--{0..1}--[ TT_Priority              ]
   |         |<>----------[ TT_Status                ]
   |         |<>--{0..1}--[ Additional_Data          ]
   |         |<>--{0..1}--[ Related_Activity         ]
   |         |<>----------[ History                  ]
   |         |<>--{0..1}--[ Hash                     ]
   |         |<>--{0..1}--[ TT_Source                ]
   |         |<>--{0..1}--[ Affected_Community       ]
   |         |<>--{0..1}--[ Affected_Service         ]
   +---------+

                     Figure 4: the Ticket class

   lang
     Required.

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   The Field Names are the Aggregate Classes that constitute the
   NTTDM and each of them is an element that is characterized by a
   quadruple (DESCRIPTION, TYPE, VALID FORMAT, MANDATORY).

3.2.3 Ticket origin information

3.2.3.1 PARTNER_ID

   +--------------+
   | PARTNER_ID   |
   +--------------+
   | DESCRIPTION  |
   | TYPE         |
   | VALID FORMAT |
   | MANDATORY    |
   +--------------+

                    Figure 5: Partner_ID Class

   DESCRIPTION: This field contains the unique ID of the TT source
                partner.

   TYPE: This attribute contains a MULTIPLE value.

   VALID FORMAT: This attribute contains a STRING value.

   MANDATORY: YES. This information is required.

3.2.3.2 ORIGINAL_ID

   +--------------+
   | ORIGINAL_ID  |
   +--------------+
   | DESCRIPTION  |
   | TYPE         |
   | VALID FORMAT |
   | MANDATORY    |
   +--------------+

                    Figure 6: Original_ID Class

   DESCRIPTION: This field contains the TT ID that was assigned by the party.

   TYPE: This attribute contains a Free value.

   VALID FORMAT: This attribute contains a String value.


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   MANDATORY: YES. This information is required.

3.2.4 Ticket information

3.2.4.1 TT_ID
 
   +--------------+
   | TT_ID        |
   +--------------+
   | DESCRIPTION  |
   | TYPE         |
   | VALID FORMAT |
   | MANDATORY    |
   +--------------+

                     Figure 7: TT_ID Class

   DESCRIPTION: This field contains contains the unique ID of the
                TT.

   TYPE: It is built the following way "PARTNER_ID"_"ORIGINAL_ID".
         PARTNER_ID   and  ORIGINAL_ID  MUST  therefore   not  
         contain  an underscore character.

   VALID FORMAT: This attribute contains a String value.

   MANDATORY: YES. This information is required.

3.2.4.2 TT_TITLE

   +---------------+
   | TT_TITLE      |
   +---------------+
   | DESCRIPTION   |
   | TYPE          |
   | VALID FORMAT  |
   | MANDATORY     |
   +---------------+

                      Figure 8: TT_Title Class

   DESCRIPTION: The title of the TT.

   TYPE: This attribute contains a Defined value.

   VALID FORMAT: This attribute contains a String value.


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   MANDATORY: YES. This information is required.

3.2.4.3 TT_TYPE

   +---------------+
   | TT_TYPE       |
   +---------------+
   | DESCRIPTION   |
   | TYPE          |
   | VALID FORMAT  |
   | MANDATORY     |
   +---------------+

                     Figure 9: Type Class

   DESCRIPTION: The type of the TT.
   
   TYPE: This attribute contains a Multiple value.

   VALID FORMAT: This attribute contains a Predefined String
                 value.

   MANDATORY: YES. This information is required.

3.2.4.4 TT_PRIORITY

   +--------------+
   | TT_PRIORITY  |
   +--------------+
   | DESCRIPTION  |
   | TYPE         |
   | VALID FORMAT |
   | MANDATORY    |
   +--------------+

                     Figure 10: TT_Priority Class

   DESCRIPTION: The TT priority.

   TYPE: This attribute contains a Multiple value.

   VALID FORMAT: This attribute contains a Predefined String
                 value.

   MANDATORY: No. This information is optional.



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3.2.4.5 TT_STATUS

   +--------------+
   | TT_STATUS    |
   +--------------+
   | DESCRIPTION  |
   | TYPE         |
   | VALID FORMAT |
   | MANDATORY    |
   +--------------+

                     Figure 11: TT_Status Class

   DESCRIPTION: The TT status.

   TYPE: This attribute contains a Multiple value.

   VALID FORMAT: This attribute contains a Predefined String
                 value.

   MANDATORY: Yes. This information is required.

3.2.4.6 TT_SOURCE

   +--------------+
   | TT_SOURCE    |
   +--------------+
   | DESCRIPTION  |
   | TYPE         |
   | VALID FORMAT |
   | MANDATORY    |
   +--------------+

                     Figure 12: TT_Source Class

   DESCRIPTION: The source of the ticket.

   TYPE: This attribute contains a Multiple value.

   VALID FORMAT: This attribute contains a Predefined String
                 value.

   MANDATORY: No. This information is optional.





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3.2.4.7 TT_OPEN_DATETIME

   +------------------+
   | TT_OPEN_DATETIME |
   +------------------+
   | DESCRIPTION      |
   | TYPE             |
   | VALID FORMAT     |
   | MANDATORY        |
   +------------------+

                     Figure 13: TT_Open_Datetime Class

   DESCRIPTION: The the datetime when the TT was opened.

   TYPE: This attribute contains a Multiple value.

   VALID FORMAT: This attribute contains a Datetime value.

   MANDATORY: YES. This information is required.

3.2.4.8 TT_CLOSE_DATETIME

   +-------------------+
   | TT_CLOSE_DATETIME |
   +-------------------+
   | DESCRIPTION       |
   | TYPE              |
   | VALID FORMAT      |
   | MANDATORY         |
   +-------------------+

                   Figure 14: TT_Close_Datetime Class

   DESCRIPTION: The datetime when the TT was closed.

   TYPE: This attribute contains a Multiple value.

   VALID FORMAT: This attribute contains a Datetime value.

   MANDATORY: YES. This information is required.



 



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3.2.5 Trouble details

3.2.5.1 TT_SHORT_DESCRIPTION

   +----------------------+
   | TT_SHORT_DESCRIPTION |
   +----------------------+
   | DESCRIPTION          |
   | TYPE                 |
   | VALID FORMAT         |
   | MANDATORY            |
   +----------------------+

                 Figure 15: TT_Short_Description Class

   DESCRIPTION: The short description of the TT.

   TYPE: This attribute contains a Multiple value.

   VALID FORMAT: This attribute contains a Predefined String
                 value.

   MANDATORY: YES. This information is required.

3.2.5.2 TT_LONG_DESCRIPTION

   +---------------------+
   | TT_LONG_DESCRIPTION |
   +---------------------+
   | DESCRIPTION         |
   | TYPE                |
   | VALID FORMAT        |
   | MANDATORY           |
   +---------------------+

                 Figure 16: TT_Long_Description Class

   DESCRIPTION: The detailed description of the
                incident/maintenance reported in the TT.

   TYPE: This attribute contains a Free value.

   VALID FORMAT: This attribute contains a String value.

   MANDATORY: YES. This information is required.



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3.2.5.3 TYPE

   +--------------+
   | TYPE         |
   +--------------+
   | DESCRIPTION  |
   | TYPE         |
   | VALID FORMAT |
   | MANDATORY    |
   +--------------+

                        Figure 17: Type Class

   DESCRIPTION: The type of the trouble.

   TYPE: This attribute contains a Multiple value.

   VALID FORMAT: This attribute contains a Predefined String
                 value.

   MANDATORY: YES. This information is required.

3.2.5.4 TT_IMPACT_ASSESSMENT

   +----------------------+
   | TT_IMPACT_ASSESSMENT |
   +----------------------+
   | DESCRIPTION          |
   | TYPE                 |
   | VALID FORMAT         |
   | MANDATORY            |
   +----------------------+

               Figure 18: TT_Impact_Assessement Class

   DESCRIPTION: The impact of the incident/maintenance.

   TYPE: This attribute contains a Multiple value.

   VALID FORMAT: This attribute contains a Predefined String
                 value.

   MANDATORY: YES. This information is required.





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3.2.5.5 START_DATETIME

   +----------------+
   | START_DATETIME |
   +----------------+
   | DESCRIPTION    |
   | TYPE           |
   | VALID FORMAT   |
   | MANDATORY      |
   +----------------+

                   Figure 19: Start_Datetime Class

   DESCRIPTION: The   datetime   that   the   incident/maintenance
                started.

   TYPE: This attribute contains a Multiple value.

   VALID FORMAT: This attribute contains a Datetime value.

   MANDATORY: YES. This information is required.

3.2.5.6 DETECT_DATETIME

   +-------------------+
   | DETECT_DATETIME   |
   +-------------------+
   | DESCRIPTION       |
   | TYPE              |
   | VALID FORMAT      |
   | MANDATORY         |
   +-------------------+

                   Figure 20: Detect_Datetime Class

   DESCRIPTION: The datetime when the incident was detected.

   TYPE: This attribute contains a Multiple value.

   VALID FORMAT: This attribute contains a Datetime value.

   MANDATORY: No. This information is optional.






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3.2.5.7 REPORT_DATETIME

   +-----------------+
   | REPORT_DATETIME |
   +-----------------+
   | DESCRIPTION     |
   | TYPE            |
   | VALID FORMAT    |
   | MANDATORY       |
   +-----------------+

                   Figure 21: Report_Datetime Class

   DESCRIPTION: The datetime when the incident was reported.

   TYPE: This attribute contains a Multiple value.

   VALID FORMAT: This attribute contains a Datetime value.

   MANDATORY: No. This information is optional.

3.2.5.8 END_DATETIME

   +--------------+
   | END_DATETIME |
   +--------------+
   | DESCRIPTION  |
   | TYPE         |
   | VALID FORMAT |
   | MANDATORY    | 
   +--------------+

                    Figure 22: End_Datetime Class

   DESCRIPTION: The datetime when the incident/maintenance ended.

   TYPE: This attribute contains a Multiple value.

   VALID FORMAT: This attribute contains a Datetime value.

   MANDATORY: YES. This information is required.







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3.2.5.9 TT_LAST_UPDATE_TIME

   +---------------------+
   | TT_LAST_UPDATE_TIME |
   +---------------------+
   | DESCRIPTION         |
   | TYPE                |
   | VALID FORMAT        |
   | MANDATORY           |
   +---------------------+

                 Figure 23: TT_Last_Update_Time Class

   DESCRIPTION: The last datetime when the TT was updated.

   TYPE: This attribute contains a Multiple value.

   VALID FORMAT: This attribute contains a Datetime value.

   MANDATORY: YES. This information is required.

3.2.5.10 TIME_WINDOW_START

   +-------------------+
   | TIME_WINDOW_START |
   +-------------------+
   | DESCRIPTION       |
   | TYPE              |
   | VALID FORMAT      |
   | MANDATORY         |
   +-------------------+

                  Figure 24: Time_Window_Start Class

   DESCRIPTION: The window start time in which planned maintenance
                may occur.

   TYPE: This attribute contains a Multiple value.

   VALID FORMAT: This attribute contains a Datetime value.

   MANDATORY: No. This information is optional. However, it is
              mandatory if the TYPE element contains the string
              "Scheduled".




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3.2.5.11 TIME_WINDOW_END

   +-----------------+
   | TIME_WINDOW_END |
   +-----------------+
   | DESCRIPTION     |
   | TYPE            |
   | VALID FORMAT    |
   | MANDATORY       |
   +-----------------+

                   Figure 25: Time_Window_End Class

   DESCRIPTION: The window end time in which planned maintenance
                may occur.

   TYPE: This attribute contains a Multiple value.

   VALID FORMAT: This attribute contains a Datetime value.

   MANDATORY: No. This information is optional. However, it is
              mandatory if the TYPE element contains the string 
              "Scheduled".

3.2.5.12 WORK_PLAN_START_DATETIME

   +--------------------------+
   | WORK_PLAN_START_DATETIME |
   +--------------------------+
   | DESCRIPTION              |
   | TYPE                     |
   | VALID FORMAT             |
   | MANDATORY                |
   +--------------------------+

              Figure 26: Work_Plan_Start_Datetime Class

   DESCRIPTION: Work planned (expected) start time in case of
                maintenance.

   TYPE: This attribute contains a Multiple value.

   VALID FORMAT: This attribute contains a Datetime value.

   MANDATORY: No. This information is optional.


 
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3.2.5.13 WORK_PLAN_END_DATETIME

   +------------------------+
   | WORK_PLAN_END_DATETIME |
   +------------------------+
   | DESCRIPTION            |
   | TYPE                   |
   | VALID FORMAT           |
   | MANDATORY              |
   +------------------------+

                Figure 27: Work_Plan_End_Datetime Class

   DESCRIPTION: Work planned (expected) end time in case of
                maintenance.

   TYPE: This attribute contains a Multiple value.

   VALID FORMAT: This attribute contains a Datetime value.

   MANDATORY: No. This information is optional.

   The period delimited by WORK_PLAN_START_DATETIME and
   WORK_PLAN_END_DATETIME must be included in the period delimited
   by TIME_WINDOW_START and TIME_WINDOW_END, duplicated with
   {START, END}_DATETIME, even in case of maintenance.

3.2.6 Related data

3.2.6.1 RELATED_EXTERNAL_TICKETS

   +--------------------------+
   | RELATED_EXTERNAL_TICKETS |
   +--------------------------+
   | DESCRIPTION              |
   | TYPE                     |
   | VALID FORMAT             |
   | MANDATORY                |
   +--------------------------+

              Figure 28: Related_External_Tickets Class

   DESCRIPTION: The NOC entity related to the incident.

   TYPE: This attribute contains a List value.

   VALID FORMAT: This attribute contains a String value.

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   MANDATORY: No. This information is optional.

3.2.6.2 ADDITIONAL_DATA

   +-----------------+
   | ADDITIONAL_DATA |
   +-----------------+
   | DESCRIPTION     |
   | TYPE            |
   | VALID FORMAT    |
   | MANDATORY       |
   +-----------------+

                    Figure 29: Additional_Data Class

   DESCRIPTION: Additional information.

   TYPE: This attribute contains a Free value.

   VALID FORMAT: This attribute contains a String value.

   MANDATORY: No. This information is optional.

3.2.6.3 RELATED_ACTIVITY

   +------------------+
   | RELATED_ACTIVITY |
   +------------------+
   | DESCRIPTION      |
   | TYPE             |
   | VALID FORMAT     |
   | MANDATORY        |
   +------------------+

                   Figure 30: Related_Activity Class

   DESCRIPTION: The trouble TT IDs of the related incidents.

   TYPE: This attribute contains a Multiple value.

   VALID FORMAT: This attribute contains a String value.

   MANDATORY: No. This information is optional.





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3.2.6.4 HISTORY

   +--------------+
   | HISTORY      |
   +--------------+
   | DESCRIPTION  |
   | TYPE         |
   | VALID FORMAT |
   | MANDATORY    |
   +--------------+

                       Figure 31: History Class

   DESCRIPTION: The necessary Actions/events log.

   TYPE: This attribute contains a Free value.

   VALID FORMAT: This attribute contains a String value.

   MANDATORY: Yes. This information is required.

   This field must NOT be empty when the VALID FORMAT attribute of
   the TT_STATUS field is different from "OPENED" or
   "OPENED/CLOSED".

3.2.7 Localization and Impact

3.2.7.1 AFFECTED_COMMUNITY

   +--------------------+
   | AFFECTED_COMMUNITY |
   +--------------------+
   | DESCRIPTION        |
   | TYPE               |
   | VALID FORMAT       |
   | MANDATORY          |
   +--------------------+

                  Figure 32: Affected_Community Class

   DESCRIPTION: Information about the community that was affected
                by the trouble incident.

   TYPE: This attribute contains a Free value.

   VALID FORMAT: This attribute contains a String value.


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   MANDATORY: No. This information is optional.

3.2.7.2 AFFECTED_SERVICE

   +------------------+
   | AFFECTED_SERVICE |
   | DESCRIPTION      |
   | TYPE             |
   | VALID FORMAT     |
   | MANDATORY        |
   +------------------+

                  Figure 33: Affected_Service Class

   DESCRIPTION: The service that was affected by the trouble
                incident.

   TYPE: This attribute contains a Multiple value.

   VALID FORMAT: This attribute contains a String value.

   MANDATORY: No. This information is optional.

3.2.7.3 LOCATION

   +--------------+
   | LOCATION     |
   +--------------+
   | DESCRIPTION  |
   | TYPE         |
   | VALID FORMAT |
   | MANDATORY    |
   +--------------+

                        Figure 34: Location Class

   DESCRIPTION: Location (Pop site, city, etc) of the incident/
                maintenance.

   TYPE: This attribute contains a Multiple value.

   VALID FORMAT: This attribute contains a String value.

   MANDATORY: YES. This information is required.




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3.2.7.4 NETWORK_NODE

   +--------------+
   | NETWORK_NODE |
   +--------------+
   | DESCRIPTION  |
   | TYPE         |
   | VALID FORMAT |
   | MANDATORY    |
   +--------------+

                     Figure 35: Network_Node Class

   DESCRIPTION: The NOC network node related to the incident.

   TYPE: This attribute contains a List value.

   VALID FORMAT: This attribute contains a String value.

   MANDATORY: No. This information is optional.

3.2.7.5 NETWORK_LINK_CIRCUIT

   +----------------------+
   | NETWORK_LINK_CIRCUIT |
   +----------------------+
   | DESCRIPTION          |
   | TYPE                 |
   | VALID FORMAT         |
   | MANDATORY            |
   +----------------------+

                Figure 36: Network_Link_Circuit Class

   DESCRIPTION: Name of the network line related to the incident.

   TYPE: This attribute contains a List value.

   VALID FORMAT: This attribute contains a String value.

   MANDATORY: No. This information is optional.







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3.2.7.6 END_LINE_LOCATION_A

   +---------------------+
   | END_LINE_LOCATION_A |
   +---------------------+
   | DESCRIPTION         |
   | TYPE                |
   | VALID FORMAT        |
   | MANDATORY           |
   +---------------------+

                 Figure 37: End_Line_Location_A Class

   DESCRIPTION: A-end of the link.

   TYPE: This attribute contains a Multiple value.

   VALID FORMAT: This attribute contains a String value.

   MANDATORY: No. This information is optional.

3.2.7.7 END_LINE_LOCATION_B

   +---------------------+
   | END_LINE_LOCATION_B |
   +---------------------+
   | DESCRIPTION         |
   | TYPE                |
   | VALID FORMAT        |
   | MANDATORY           |
   +---------------------+

                 Figure 38: End_Line_Location_B Class

   DESCRIPTION: B-end of the link.

   TYPE: This attribute contains a Multiple value.

   VALID FORMAT: This attribute contains a String value.

   MANDATORY: No. This information is optional.







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3.2.8 Contact information

3.2.8.1 OPEN_ENGINEER

   +---------------+
   | OPEN_ENGINEER |
   +---------------+
   | DESCRIPTION   |
   | TYPE          |
   | VALID FORMAT  |
   | MANDATORY     |
   +---------------+

                    Figure 39: Open_Engineer Class

   DESCRIPTION: The engineer that opened the ticket.

   TYPE: This attribute contains a Multiple value.

   VALID FORMAT: This attribute contains a String value.

   MANDATORY: No. This information is optional.

3.2.8.2 CONTACT_ENGINEERS

   +-------------------+
   | CONTACT_ENGINEERS |
   +-------------------+
   | DESCRIPTION       |
   | TYPE              |
   | VALID FORMAT      |
   | MANDATORY         |
   +-------------------+

                   Figure 40: Contact_Engineers Class

   DESCRIPTION: The engineers responsible for the incident
                settlement.

   TYPE: This attribute contains a List value.

   VALID FORMAT: This attribute contains a String value.

   MANDATORY: No. This information is optional.




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3.2.8.3 CLOSE_ENGINEER

   +----------------+
   | CLOSE_ENGINEER |
   +----------------+
   | DESCRIPTION    |
   | TYPE           |
   | VALID FORMAT   |
   | MANDATORY      |
   +----------------+

                    Figure 41: Close_Engineer Class

   DESCRIPTION: The engineer that closed the ticket.

   TYPE: This attribute contains a Multiple value.

   VALID FORMAT: This attribute contains a String value.

   MANDATORY: No. This information is optional.

3.2.9 Security

3.2.9.1 HASH

   +-------------+
   | HASH        |
   +-------------+
   | DESCRIPTION |
   | TYPE        |
   | VALID FORMAT|
   | MANDATORY   |
   +-------------+

                        Figure 42: Hash Class

   DESCRIPTION: Encrypted message hash.

   TYPE: This attribute contains a Defined value.

   VALID FORMAT: This attribute contains a String value.

   MANDATORY: No. This information is optional.

3.3 NTTDM Representation

   The collected and processed TTs received from multiple

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   telecommunications networks are adjusted in a normalized NTTDM.
   Below, there is the representation of this normalized Data
   Model. The "DESCRIPTION" attribute is implied.
   +------------------------+--------+------------------+---------+
   | FIELD NAME             | TYPE   |VALID FORMAT      |MANDATORY|
   +------------------------+--------+------------------+---------+
   |PARTNER_ID              |MULTIPLE|STRING            |YES      |
   |ORIGINAL_ID             |FREE    |STRING            |YES      |
   |TT_ID                   |DEFINED |STRING            |YES      |
   |TT_OPEN_DATETIME        |MULTIPLE|DATETIME          |YES      |
   |TT_CLOSE_DATETIME       |MULTIPLE|DATETIME          |YES      |
   |START_DATETIME          |MULTIPLE|DATETIME          |YES      |
   |DETECT_DATETIME         |MULTIPLE|DATETIME          |NO       |
   |REPORT_DATETIME         |MULTIPLE|DATETIME          |NO       |
   |END_DATETIME            |MULTIPLE|DATETIME          |YES      |
   |TT_LAST_UPDATE_TIME     |MULTIPLE|DATETIME          |YES      |
   |TIME_WINDOW_START       |MULTIPLE|DATETIME          |NO       |
   |TIME_WINDOW_END         |MULTIPLE|DATETIME          |NO       |
   |WORK_PLAN_START_DATETIME|MULTIPLE|DATETIME          |NO       |
   |WORK_PLAN_END_DATETIME  |MULTIPLE|DATETIME          |NO       |
   |TT_TITLE                |DEFINED |STRING            |YES      |
   |TT_SHORT_DESCRIPTION    |MULTIPLE|PREDEFINED STRING |YES      |
   |TT_LONG_DESCRIPTION     |FREE    |STRING            |NO       |
   |TYPE                    |MULTIPLE|PREDEFINED STRING |YES      |
   |TT_TYPE                 |MULTIPLE|PREDEFINED STRING |YES      |
   |TT_IMPACT_ASSESSMENT    |MULTIPLE|PREDEFINED STRING |YES      |
   |RELATED_EXTERNAL_TICKETS|LIST    |STRING            |NO       |
   |LOCATION                |MULTIPLE|STRING            |YES      |
   |NETWORK_NODE            |LIST    |STRING            |NO       |
   |NETWORK_LINK_CIRCUIT    |LIST    |STRING            |NO       |
   |END_LINE_LOCATION_A     |MULTIPLE|STRING            |NO       |
   |END_LINE_LOCATION_B     |MULTIPLE|STRING            |NO       |
   |OPEN_ENGINEER           |MULTIPLE|STRING            |NO       |
   |CONTACT_ENGINEERS       |LIST    |STRING            |NO       |
   |CLOSE_ENGINEER          |MULTIPLE|STRING            |NO       |
   |TT_PRIORITY             |MULTIPLE|PREDEFINED STRING |NO       |
   |TT_STATUS               |MULTIPLE|PREDEFINED STRING |YES      |
   |ADDITIONAL_DATA         |FREE    |STRING            |NO       |
   |RELATED_ACTIVITY        |MULTIPLE|STRING            |NO       |
   |HISTORY                 |FREE    |STRING            |YES      | 
   |HASH                    |DEFINED |STRING            |NO       | 
   |TT_SOURCE               |MULTIPLE|STRING            |NO       |
   |AFFECTED_COMMUNITY      |FREE    |STRING            |NO       |
   |AFFECTED_SERVICE        |MULTIPLE|STRING            |NO       |
   +------------------------+--------+------------------+---------+
 
                 Figure 43: the Field Name class

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4. Internationalization Issues

   Internationalization and localization is of specific concern to
   the NTTDM, since it is only through collaboration, often across
   language barriers, that certain incidents be resolved. The
   NTTDM supports this goal by depending on XML constructs, and
   through explicit design choices in the data model.
   The main advantage of the model is that it provides a
   normalized data type that is implemented fully in the English
   language and can be used conveniently. It also supports Free
   formed text that can be written in any language. In the future
   it will provide translation services for all the free-formed
   text.

5. Examples      

5.1 Link Failure

   In this section an example is provided of network TTs exchanged
   using the proposed format. This is an actual GRNet ticket
   normalized according to TTDM. Fields that were not included in
   the ticket are left blank.

   <?xml version="1.0" encoding="UTF-8" ?>
   <!-- This example describes a link failure that was detected --
   >
   <NTTDM-Document version="1.00" lang="gr"
      xmlns="urn:ietf:params:xml:ns:NTTDM-1.0"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      xsi:schemaLocation="urn:ietf:params:xml:schema:NTTDM-1.0">
     <Ticket>
          <Partner_ID> 01 </Partner_ID>
          <Original_ID> 5985 </Original_ID>
          <TT_ID> 01_5985 </TT_ID>
          <TT_Open_Datetime> 2008-12-16T10:01:15+0200
   </TT_Open_Datetime>
          <TT_Close_Datetime> 2008-12-16T15:05:00+0200
   </TT_Close_Datetime>
          <Start_Datetime> 2008-12-16T09:55:00+0200
   </Start_Datetime>
          <End_Datetime> 2008-12-16T15:01:21+0200 </End_Datetime>
          <TT_Last_Update_Time> 2008-12-16T15:00:34+0200
   </TT_Last_Update_Time>
          <TT_Title> Forth Link Failure </TT_Title>
          <TT_Short_Description> Core Line Fault
   </TT_Short_Description>
          <TT_Long_Description> Forth Link Failure

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   </TT_Long_Description>
          <Type> Unscheduled </Type>
          <TT_Type> Operational    </TT_Type>
          <TT_Impact_Assessment> No Connectivity
   </TT_Impact_Assessment>
          <Location> HERAKLION </Location>
          <Network_Node> FORTH </Network_Node>
          <Network_Link_Circuit> FORTH-2 </Network_Link_Circuit>
          <Open_Engineer> Dimitris Zisiadis </Open_Engineer>
          <Close_Engineer> Dimitris Zisiadis </Close_Engineer>
          <TT_Priority> High </TT_Priority>
          <TT_Status> Closed </TT_Status>
     </Ticket>
   </NTTDM-Document>

6. Sample implementation: XML schema

   This section provides the XML Schema of the NTTDM.

  <?xml version="1.0" encoding="utf-8"?>
  <xs:schema xmlns="urn:ietf:params:xml:ns:nttdm-0.1"
  xmlns:nttdm="urn:ietf:params:xml:ns:nttdm-1.0"
  xmlns:xs="http://www.w3.org/2001/XMLSchema"
  targetNamespace="urn:ietf:params:xml:ns:nttdm-1.0"
  elementFormDefault="qualified"
  attributeFormDefault="unqualified">
   <xs:annotation>
       <xs:documentation>
      Trouble Ticket Data Model v-1.0
       </xs:documentation>
   </xs:annotation>
   <!--
  ===============================================================
  == NTTDM-Document class                                      ==
  ===============================================================
   -->
   <xs:element name="NTTDM-Document">
         <xs:complexType>
               <xs:sequence>
                    <xs:element ref="nttdm:Incident"
   maxOccurs="unbounded"/>
                </xs:sequence>
                <xs:attribute name="version" type="xs:string"
   fixed="1.00"/>
                <xs:attribute name="lang" type="xs:language"
   use="required"/>
         </xs:complexType>

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   </xs:element>
   <!--
  ===============================================================
  ==  Incident class                                           ==
  ===============================================================
   -->
   <xs:element name="Incident">
        <xs:complexType>
              <xs:sequence>
                    <xs:element ref="nttdm:Partner_ID"/>
                    <xs:element ref="nttdm:Original_ID"/>
                    <xs:element ref="nttdm:TT_ID"/>
                    <xs:element ref="nttdm:TT_Open_Datetime"/>
                    <xs:element ref="nttdm:TT_Close_Datetime"/>
                    <xs:element ref="nttdm:Start_Datetime"/>
                    <xs:element ref="nttdm:Detect_Datetime"/>
                    <xs:element ref="nttdm:Report_Datetime"/>
                    <xs:element ref="nttdm:End_Datetime"/>
                    <xs:element ref="nttdm:TT_Last_Update_Time"/>
                    <xs:element ref="nttdm:Time_Window_Start"/>
                    <xs:element ref="nttdm:Time_Window_End"/>
                    <xs:element ref="nttdm:Work_Plan_Start_Datetime"/>
                    <xs:element ref="nttdm:Work_Plan_End_Datetime"/>
                    <xs:element ref="nttdm:TT_Title"/>
                    <xs:element ref="nttdm:TT_Short_Description"/>
                    <xs:element ref="nttdm:TT_Long_Description"/>
                    <xs:element ref="nttdm:Type"/>
                    <xs:element ref="nttdm:TT_Type"/>
                    <xs:element ref="nttdm:TT_Impact_Assessment"/>
                    <xs:element ref="nttdm:Related_External_Tickets"/>
                    <xs:element ref="nttdm:Location"/>
                    <xs:element ref="nttdm:Network_Node"/>
                    <xs:element ref="nttdm:Network_Link_Circuit"/>
                    <xs:element ref="nttdm:End_Line_Location_A"/>
                    <xs:element ref="nttdm:End_Line_Location_B"/>
                    <xs:element ref="nttdm:Open_Engineer"/>
                    <xs:element ref="nttdm:Contact_Engineers"/>
                    <xs:element ref="nttdm:Close_Engineer"/>
                    <xs:element ref="nttdm:TT_Priority"/>
                    <xs:element ref="nttdm:TT_Status"/>
                    <xs:element ref="nttdm:Additional_Data"/>
                    <xs:element ref="nttdm:Related_Activity"/>
                    <xs:element ref="nttdm:History"/>
                    <xs:element ref="nttdm:Hash"/>
                    <xs:element ref="nttdm:TT_Source"/>
                    <xs:element ref="nttdm:Affected_Community"/>
                    <xs:element ref="nttdm:Affected_Service"/>

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               </xs:sequence>
               <xs:attribute name="lang" type="xs:language"/>
         </xs:complexType>
   </xs:element>
   <!--
  ===============================================================
  ==  Partner_ID Class                                         ==
  ===============================================================
   -->
   <xs:element name="Partner_ID" type="nttdm:Partner_IDType"/>
     <xs:complexType name="Partner_IDType">
         <xs:simpleContent>
               <xs:extension base="xs:string">
                    <xs:attribute name="Description"
     type="xs:string" fixed="The unique ID of the TT source partner"/>
                    <xs:attribute name="Type"
     type="nttdm:Multiple" use="required"/>
                    <xs:attribute name="Valid_Format"
     type="xs:string" use="required"/>
                    <xs:attribute name="Mandatory"
     type="xs:string" default="Yes"/>
               </xs:extension>
         </xs:simpleContent>
     </xs:complexType>
     <!--
  ===============================================================
  ==  Original_ID class                                        ==
  ===============================================================
     -->
     <xs:element name="Original_ID" type="nttdm:Original_IDType"/>
     <xs:complexType name="Original_IDType">
         <xs:simpleContent>
               <xs:extension base="xs:string">
                    <xs:attribute name="Description"
   type="xs:string" fixed="The trouble ticket ID that was assigned
   by the party"/>
                    <xs:attribute name="Type" type="nttdm:Free"
   use="required"/>
                    <xs:attribute name="Valid_Format"
   type="xs:string" use="required"/>
                    <xs:attribute name="Mandatory"
   type="xs:string" default="Yes"/>
               </xs:extension>
         </xs:simpleContent>
    </xs:complexType>



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    <!--
  ===============================================================
  ==  TT_ID class                                              ==
  ===============================================================
    -->
    <xs:element name="TT_ID" type="nttdm:TT_IDType"/>
    <xs:complexType name="TT_IDType">
         <xs:simpleContent>
               <xs:extension base="xs:string">
                    <xs:attribute name="Description"
  type="xs:string" fixed="The unique ID of the TT"/>
                    <xs:attribute name="Type" type="nttdm:Defined"
  use="required"/>
                    <xs:attribute name="Valid_Format"
  type="xs:string" use="required"/>
                    <xs:attribute name="Mandatory"
  type="xs:string" default="Yes"/>
               </xs:extension>
         </xs:simpleContent>
    </xs:complexType>
    <!--
  ===============================================================
  ==  TT_Open_Datetime Class                                   ==
  ===============================================================
    -->
    <xs:element name="TT_Open_Datetime"
  type="nttdm:TT_Open_DatetimeType"/>
    <xs:complexType name="TT_Open_DatetimeType">
         <xs:simpleContent>
               <xs:extension base="xs:string">
                    <xs:attribute name="Description"
  type="xs:string" fixed="The datetime when the TT was opened"/>
                    <xs:attribute name="Type"
  type="nttdm:Multiple" use="required"/>
                    <xs:attribute name="Valid_Format"
  type="xs:dateTime" use="required"/>
                    <xs:attribute name="Mandatory"
  type="xs:string" default="Yes"/>
               </xs:extension>
         </xs:simpleContent>
    </xs:complexType>
    <!--
  ===============================================================
  ==  TT_Close_Datetime Class                                  ==
  ===============================================================
    -->


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    <xs:element name="TT_Close_Datetime"
  type="nttdm:TT_Close_DatetimeType"/>
    <xs:complexType name="TT_Close_DatetimeType">
         <xs:simpleContent>
               <xs:extension base="xs:string">
                    <xs:attribute name="Description"
  type="xs:string" fixed="The datetime when the TT was closed"/>
                    <xs:attribute name="Type"
  type="nttdm:Multiple" use="required"/>
                    <xs:attribute name="Valid_Format"
  type="xs:dateTime" use="required"/>
                    <xs:attribute name="Mandatory"
  type="xs:string" default="Yes"/>
               </xs:extension>
         </xs:simpleContent>
    </xs:complexType>
    <!--
  ===============================================================
  == Start_Datetime Class                                     ==
  ===============================================================
    -->
    <xs:element name="Start_Datetime"
  type="nttdm:Start_DatetimeType"/>
    <xs:complexType name="Start_DatetimeType">
         <xs:simpleContent>
               <xs:extension base="xs:string">
                    <xs:attribute name="Description"
  type="xs:string" fixed="The datetime when the
  incident/maintenance started"/>
                    <xs:attribute name="Type"
  type="nttdm:Multiple" use="required"/>
                    <xs:attribute name="Valid_Format"
  type="xs:dateTime" use="required"/>
                    <xs:attribute name="Mandatory"
  type="xs:string" default="Yes"/>
               </xs:extension>
         </xs:simpleContent>
    </xs:complexType>
    <!--
  ===============================================================
  == Detect_Datetime Class                                     ==
  ===============================================================
    -->
    <xs:element name="Detect_Datetime"
  type="nttdm:Detect_DatetimeType"/>
    <xs:complexType name="Detect_DatetimeType">


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         <xs:simpleContent>
               <xs:extension base="xs:string">
                    <xs:attribute name="Description"
  type="xs:string" fixed="The datetime when the incident was
  detected"/>
                    <xs:attribute name="Type"
  type="nttdm:Multiple"/>
                    <xs:attribute name="Valid_Format"
  type="xs:dateTime"/>
                    <xs:attribute name="Mandatory"
  type="xs:string" default="No"/>
               </xs:extension>
         </xs:simpleContent>
    </xs:complexType>
    <!--
  ===============================================================
  == Report_Datetime Class                                     ==
  ===============================================================
    -->
    <xs:element name="Report_Datetime"
  type="nttdm:Report_DatetimeType"/>
    <xs:complexType name="Report_DatetimeType">
         <xs:simpleContent>
               <xs:extension base="xs:string">
                    <xs:attribute name="Description"
  type="xs:string" fixed="The datetime when the incident was
  reported"/>
                    <xs:attribute name="Type"
  type="nttdm:Multiple"/>
                    <xs:attribute name="Valid_Format"
  type="xs:dateTime"/>
                    <xs:attribute name="Mandatory"
  type="xs:string" default="No"/>
               </xs:extension>
         </xs:simpleContent>
    </xs:complexType>
    <!--
  ===============================================================
  == End_Datetime Class                                        ==
  ===============================================================
    -->
    <xs:element name="End_Datetime"
  type="nttdm:End_DatetimeType"/>
    <xs:complexType name="End_DatetimeType">
         <xs:simpleContent>
               <xs:extension base="xs:string">


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                    <xs:attribute name="Description"
  type="xs:string" fixed="The datetime when the incident ended"/>
                    <xs:attribute name="Type"
  type="nttdm:Multiple" use="required"/>
                    <xs:attribute name="Valid_Format"
  type="xs:dateTime" use="required"/>
                    <xs:attribute name="Mandatory"
  type="xs:string" default="Yes"/>
               </xs:extension>
         </xs:simpleContent>
    </xs:complexType>
    <!--
  ===============================================================
  == TT_Last_Update_Time Class                                 ==
  ===============================================================
    -->
    <xs:element name="TT_Last_Update_Time"
  type="nttdm:TT_Last_Update_TimeType"/>
    <xs:complexType name="TT_Last_Update_TimeType">
         <xs:simpleContent>
               <xs:extension base="xs:string">
                    <xs:attribute name="Description"
  type="xs:string" fixed="The datetime when the TT was updated"/>
                    <xs:attribute name="Type"
  type="nttdm:Multiple" use="required"/>
                    <xs:attribute name="Valid_Format"
  type="xs:dateTime" use="required"/>
                    <xs:attribute name="Mandatory"
  type="xs:string" default="Yes"/>
               </xs:extension>
         </xs:simpleContent>
    </xs:complexType>
    <!--
  ===============================================================
  == Time_Window_Start Class                                   ==
  ===============================================================
    -->
    <xs:element name="Time_Window_Start"
  type="nttdm:Time_Window_StartType"/>
    <xs:complexType name="Time_Window_StartType">
         <xs:simpleContent>
               <xs:extension base="xs:string">
                    <xs:attribute name="Description"
  type="xs:string" fixed="The window start time in which planned
  maintenance may occur"/>
                    <xs:attribute name="Type"


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  type="nttdm:Multiple" use="optional"/>
                    <xs:attribute name="Valid_Format"
  type="xs:dateTime" use="optional"/>
                    <xs:attribute name="Mandatory"
  type="xs:string" default="No"/>
               </xs:extension>
         </xs:simpleContent>
    </xs:complexType>
    <!--
  ===============================================================
  == Time_Window_End Class                                     ==
  ===============================================================
    -->
    <xs:element name="Time_Window_End"
  type="nttdm:Time_Window_EndType"/>
    <xs:complexType name="Time_Window_EndType">
         <xs:simpleContent>
               <xs:extension base="xs:string">
                    <xs:attribute name="Description"
  type="xs:string" fixed="The window end time in which planned
  maintenance may occur"/>
                    <xs:attribute name="Type"
  type="nttdm:Multiple" use="optional"/>
                    <xs:attribute name="Valid_Format"
  type="xs:dateTime" use="optional"/>
                    <xs:attribute name="Mandatory"
  type="xs:string" default="No"/>
               </xs:extension>
         </xs:simpleContent>
    </xs:complexType>
    <!--
  ===============================================================
  == Work_Plan_Start_Datetime Class                            ==
  ===============================================================
    -->
    <xs:element name="Work_Plan_Start_Datetime"
  type="nttdm:Work_Plan_Start_DatetimeType"/>
    <xs:complexType name="Work_Plan_Start_DatetimeType">
         <xs:simpleContent>
               <xs:extension base="xs:string">
                    <xs:attribute name="Description"
  type="xs:string" fixed="Work planned start time in case of
  maintenancer"/>
                    <xs:attribute name="Type"
  type="nttdm:Multiple" use="optional"/>
                    <xs:attribute name="Valid_Format"
  type="xs:dateTime" use="optional"/>

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                    <xs:attribute name="Mandatory"
  type="xs:string" default="No"/>
               </xs:extension>
         </xs:simpleContent>
    </xs:complexType>
    <!--
  ===============================================================
  == Work_Plan_End_Datetime Class                              ==
  ===============================================================
    -->
    <xs:element name="Work_Plan_End_Datetime"
  type="nttdm:Work_Plan_End_DatetimeType"/>
    <xs:complexType name="Work_Plan_End_DatetimeType">
         <xs:simpleContent>
               <xs:extension base="xs:string">
                    <xs:attribute name="Description"
  type="xs:string" fixed="Work planned end time in case of
  maintenancer"/>
                    <xs:attribute name="Type"
  type="nttdm:Multiple" use="optional"/>
                    <xs:attribute name="Valid_Format"
  type="xs:dateTime" use="optional"/>
                    <xs:attribute name="Mandatory"
  type="xs:string" default="No"/>
               </xs:extension>
         </xs:simpleContent>
    </xs:complexType>
    <!--
  ===============================================================
  == TT_Title Class                                            ==
  ===============================================================
    -->
    <xs:element name="TT_Title" type="nttdm:TT_TitleType"/>
    <xs:complexType name="TT_TitleType">
         <xs:simpleContent>
               <xs:extension base="xs:string">
                    <xs:attribute name="Description"
  type="xs:string" fixed="The title of the TT"/>
                    <xs:attribute name="Type" type="nttdm:Defined"
  use="required"/>
                    <xs:attribute name="Valid_Format"
  type="xs:string" use="required"/>
                    <xs:attribute name="Mandatory"
  type="xs:string" default="Yes"/>
               </xs:extension>
         </xs:simpleContent>
    </xs:complexType>

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    <!--
  ===============================================================
  == TT_Short_Description Class                                ==
  ===============================================================
    -->
    <xs:element name="TT_Short_Description"
  type="nttdm:TT_Short_DescriptionType"/>
    <xs:complexType name="TT_Short_DescriptionType">
         <xs:simpleContent>
               <xs:extension base="xs:string">
                    <xs:attribute name="Description"
  type="xs:string" fixed="The short description of the TT"/>
                    <xs:attribute name="Type"
  type="nttdm:Multiple" use="required"/>
                    <xs:attribute name="ValidFormat"
  use="required">
                         <xs:simpleType>
                              <xs:restriction base="xs:string">
                                   <xs:enumeration value="Core
  Line Fault"/>
                                   <xs:enumeration value="Access
  Line Fault"/>
                                   <xs:enumeration value="Degraded
  Service"/>
                                   <xs:enumeration value="Router
  Hardware Fault"/>
                                   <xs:enumeration value="Router
  Software Fault"/>
                                   <xs:enumeration value="Routing
  Problem"/>
                                   <xs:enumeration
  value="Undefined Problem"/>
                                   <xs:enumeration value="Network
  Congestion"/>
                                   <xs:enumeration value="Client
  Upgrade"/>
                                   <xs:enumeration value="IPv6"/>
                                   <xs:enumeration value="QoS"/>
                                   <xs:enumeration value="Other"/>
                              </xs:restriction>
                         </xs:simpleType>
                    </xs:attribute>
                    <xs:attribute name="Mandatory"
  type="xs:string" default="Yes"/>
               </xs:extension>
         </xs:simpleContent>
    </xs:complexType>

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    <!--
  ===============================================================
  == TT_Long_Description Class                                 ==
  ===============================================================
    -->
    <xs:element name="TT_Long_Description"
  type="nttdm:TT_Long_DescriptionType"/>
    <xs:complexType name="TT_Long_DescriptionType">
         <xs:simpleContent>
               <xs:extension base="xs:string">
                    <xs:attribute name="Description"
  type="xs:string" fixed="The detailed description of the
  problem/incident/maintenance reported in the TT"/>
                    <xs:attribute name="Type" type="nttdm:Free"
  use="required"/>
                    <xs:attribute name="Valid_Format"
  type="xs:string" use="required"/>
                    <xs:attribute name="Mandatory"
  type="xs:string" default="No"/>
               </xs:extension>
         </xs:simpleContent>
    </xs:complexType>
    <!--
  ===============================================================
  ==  Type Class                                               ==
  ===============================================================
    -->
    <xs:element name="Type" type="nttdm:TypeType"/>
    <xs:complexType name="TypeType">
         <xs:simpleContent>
               <xs:extension base="xs:string">
                    <xs:attribute name="Description"
  type="xs:string" fixed="The type of the trouble"/>
                    <xs:attribute name="Type"
  type="nttdm:Multiple" use="required"/>
                    <xs:attribute name="ValidFormat"
  use="required">
                         <xs:simpleType>
                              <xs:restriction base="xs:string">
                                   <xs:enumeration
  value="Scheduled"/>
                                   <xs:enumeration
  value="Unscheduled"/>
                              </xs:restriction>
                         </xs:simpleType>
                    </xs:attribute>
                    <xs:attribute name="Mandatory"

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  type="xs:string" default="Yes"/>
               </xs:extension>
         </xs:simpleContent>
    </xs:complexType>
    <!--
  ===============================================================
  == TT_Type Class                                             ==
  ===============================================================
    -->
    <xs:element name="TT_Type" type="nttdm:TT_TypeType"/>
    <xs:complexType name="TT_TypeType">
         <xs:simpleContent>
               <xs:extension base="xs:string">
                    <xs:attribute name="Description"
  type="xs:string" fixed="The type of the TT"/>
                    <xs:attribute name="Type"
  type="nttdm:Multiple" use="required"/>
                    <xs:attribute name="ValidFormat"
  use="required">
                         <xs:simpleType>
                              <xs:restriction base="xs:string">
                                   <xs:enumeration
  value="Operational"/>
                                   <xs:enumeration
  value="Informational"/>
                                   <xs:enumeration
  value="Administrative"/>
                                   <xs:enumeration value="Test"/>
                              </xs:restriction>
                         </xs:simpleType>
                    </xs:attribute>
                    <xs:attribute name="Mandatory"
  type="xs:string" default="Yes"/>
               </xs:extension>
         </xs:simpleContent>
    </xs:complexType>
    <!--
  ===============================================================
  == TT_Impact_Assessment Class                                ==
  ===============================================================
    -->
    <xs:element name="TT_Impact_Assessment"
  type="nttdm:TT_Impact_AssessmentType"/>
    <xs:complexType name="TT_Impact_AssessmentType">
         <xs:simpleContent>
               <xs:extension base="xs:string">
                    <xs:attribute name="Description"

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  type="xs:string" fixed="The impact of the
  incident/maintenance"/>
                    <xs:attribute name="Type"
  type="nttdm:Multiple" use="required"/>
                    <xs:attribute name="ValidFormat"
  use="required">
                         <xs:simpleType>
                              <xs:restriction base="xs:string">
                                   <xs:enumeration value="No
  Impact"/>
                                   <xs:enumeration value="Redused
  Redudancy"/>
                                   <xs:enumeration value="Minor
  Performance Impact"/>
                                   <xs:enumeration value="Severe
  Performance Impact"/>
                                   <xs:enumeration value="No
  Connectivity"/>
                                   <xs:enumeration value="On
  Backup"/>
                                   <xs:enumeration value="At
  Risk"/>
                                   <xs:enumeration
  value="Unknown"/>
                              </xs:restriction>
                         </xs:simpleType>
                    </xs:attribute>
                    <xs:attribute name="Mandatory"
  type="xs:string" default="Yes"/>
               </xs:extension>
         </xs:simpleContent>
    </xs:complexType>
    <!--
  ===============================================================
  == Related_External_Tickets Class                            ==
  ===============================================================
    -->
    <xs:element name="Related_External_Tickets"
  type="nttdm:Related_External_TicketsType"/>
    <xs:complexType name="Related_External_TicketsType">
         <xs:simpleContent>
               <xs:extension base="xs:string">
                    <xs:attribute name="Description"
  type="xs:string" fixed="The NOC entity related to the
  incident"/>
                    <xs:attribute name="Type" type="nttdm:List"
  use="optional"/>

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                    <xs:attribute name="Valid_Format"
  type="xs:string" use="optional"/>
                    <xs:attribute name="Mandatory"
  type="xs:string" default="No"/>
               </xs:extension>
         </xs:simpleContent>
    </xs:complexType>
    <!--
  ===============================================================
  == Location Class                                            ==
  ===============================================================
    -->
    <xs:element name="Location" type="nttdm:LocationType"/>
    <xs:complexType name="LocationType">
         <xs:simpleContent>
               <xs:extension base="xs:string">
                    <xs:attribute name="Description"
  type="xs:string" fixed="Location (Pop site, city, etc) of the
  incident/maintenance"/>
                    <xs:attribute name="Type"
  type="nttdm:Multiple" use="required"/>
                    <xs:attribute name="Valid_Format"
  type="xs:string" use="required"/>
                    <xs:attribute name="Mandatory"
  type="xs:string" default="Yes"/>
               </xs:extension>
         </xs:simpleContent>
    </xs:complexType>
    <!--
  ===============================================================
  == Network_Node Class                                        ==
  ===============================================================
    -->
    <xs:element name="Network_Node"
  type="nttdm:Network_NodeType"/>
    <xs:complexType name="Network_NodeType">
         <xs:simpleContent>
               <xs:extension base="xs:string">
                    <xs:attribute name="Description"
  type="xs:string" fixed="The network node related to the
  incident"/>
                    <xs:attribute name="Type" type="nttdm:List"
  use="optional"/>
                    <xs:attribute name="Valid_Format"
  type="xs:string" use="optional"/>
                    <xs:attribute name="Mandatory"
  type="xs:string" default="No"/>

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               </xs:extension>
         </xs:simpleContent>
    </xs:complexType>
    <!--
  ===============================================================
  == Network_Link_Circuit Class                                ==
  ===============================================================
    -->
    <xs:element name="Network_Link_Circuit"
  type="nttdm:Network_Link_CircuitType"/>
    <xs:complexType name="Network_Link_CircuitType">
         <xs:simpleContent>
               <xs:extension base="xs:string">
                    <xs:attribute name="Description"
  type="xs:string" fixed="Name of the network line related to the
  incident"/>
                    <xs:attribute name="Type" type="nttdm:List"
  use="optional"/>
                    <xs:attribute name="Valid_Format"
  type="xs:string" use="optional"/>
                    <xs:attribute name="Mandatory"
  type="xs:string" default="No"/>
               </xs:extension>
         </xs:simpleContent>
    </xs:complexType>
    <!--
  ===============================================================
  == End_Line_Location_A Class                                 ==
  ===============================================================
    -->
    <xs:element name="End_Line_Location_A"
  type="nttdm:End_Line_Location_AType"/>
    <xs:complexType name="End_Line_Location_AType">
         <xs:simpleContent>
               <xs:extension base="xs:string">
                    <xs:attribute name="Description"
  type="xs:string" fixed="A-end of the link"/>
                    <xs:attribute name="Type"
  type="nttdm:Multiple" use="optional"/>
                    <xs:attribute name="Valid_Format"
  type="xs:string" use="optional"/>
                    <xs:attribute name="Mandatory"
  type="xs:string" default="No"/>
              </xs:extension>
         </xs:simpleContent>
    </xs:complexType>


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    <!--
  ===============================================================
  ==  End_Line_Location_B Class                                ==
  ===============================================================
    -->
    <xs:element name="End_Line_Location_B"
  type="nttdm:End_Line_Location_BType"/>
    <xs:complexType name="End_Line_Location_BType">
         <xs:simpleContent>
               <xs:extension base="xs:string">
                    <xs:attribute name="Description"
  type="xs:string" fixed="B-end of the link"/>
                    <xs:attribute name="Type"
  type="nttdm:Multiple" use="optional"/>
                    <xs:attribute name="Valid_Format"
  type="xs:string" use="optional"/>
                    <xs:attribute name="Mandatory"
  type="xs:string" default="No"/>
               </xs:extension>
         </xs:simpleContent>
    </xs:complexType>
    <!--
  ===============================================================
  == Open_Engineer Class                                       ==
  ===============================================================
    -->
    <xs:element name="Open_Engineer"
  type="nttdm:Open_EngineerType"/>
    <xs:complexType name="Open_EngineerType">
         <xs:simpleContent>
               <xs:extension base="xs:string">
                    <xs:attribute name="Description"
  type="xs:string" fixed="The engineer that opened the ticket"/>
                    <xs:attribute name="Type"
  type="nttdm:Multiple" use="optional"/>
                    <xs:attribute name="Valid_Format"
  type="xs:string" use="optional"/>
                    <xs:attribute name="Mandatory"
  type="xs:string" default="No"/>
               </xs:extension>
         </xs:simpleContent>
    </xs:complexType>
    <!--
  ===============================================================
  == Contact_Engineers Class                                   ==
  ===============================================================
    -->

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    <xs:element name="Contact_Engineers"
  type="nttdm:Contact_EngineersType"/>
    <xs:complexType name="Contact_EngineersType">
         <xs:simpleContent>
               <xs:extension base="xs:string">
                    <xs:attribute name="Description"
  type="xs:string" fixed="The engineers responsible for the
  incident settlement"/>
                    <xs:attribute name="Type" type="nttdm:List"
  use="optional"/>
                    <xs:attribute name="Valid_Format"
  type="xs:string" use="optional"/>
                    <xs:attribute name="Mandatory"
  type="xs:string" default="No"/>
               </xs:extension>
         </xs:simpleContent>
    </xs:complexType>
    <!--
  ===============================================================
  == Close_Engineer Class                                      ==
  ===============================================================
    -->
    <xs:element name="Close_Engineer"
  type="nttdm:Close_EngineerType"/>
    <xs:complexType name="Close_EngineerType">
         <xs:simpleContent>
               <xs:extension base="xs:string">
                    <xs:attribute name="Description"
  type="xs:string" fixed="The engineer that closed the ticket"/>
                    <xs:attribute name="Type"
  type="nttdm:Multiple" use="optional"/>
                    <xs:attribute name="Valid_Format"
  type="xs:string" use="optional"/>
                    <xs:attribute name="Mandatory"
  type="xs:string" default="No"/>
               </xs:extension>
         </xs:simpleContent>
    </xs:complexType>
    <!--
  ===============================================================
  == TT_Priority Class                                         ==
  ===============================================================
    -->
    <xs:element name="TT_Priority" type="nttdm:TT_PriorityType"/>
    <xs:complexType name="TT_PriorityType">
         <xs:simpleContent>
               <xs:extension base="xs:string">

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                    <xs:attribute name="Description"
  type="xs:string" fixed="The trouble ticket priority"/>
                    <xs:attribute name="Type"
  type="nttdm:Multiple" use="optional"/>
                    <xs:attribute name="ValidFormat"
  use="optional">
                         <xs:simpleType>
                              <xs:restriction base="xs:string">
                                   <xs:enumeration value="Low"/>
                                   <xs:enumeration
  value="Medium"/>
                                   <xs:enumeration value="High"/>
                              </xs:restriction>
                         </xs:simpleType>
                    </xs:attribute>
                    <xs:attribute name="Mandatory"
  type="xs:string" default="No"/>
               </xs:extension>
         </xs:simpleContent>
    </xs:complexType>
    <!--
  ===============================================================
  == TT_Status Class                                           ==
  ===============================================================
    -->
    <xs:element name="TT_Status" type="nttdm:TT_StatusType"/>
    <xs:complexType name="TT_StatusType">
         <xs:simpleContent>

               <xs:extension base="xs:string">
                    <xs:attribute name="Description"
  type="xs:string" fixed="The trouble ticket status"/>
                    <xs:attribute name="Type"
  type="nttdm:Multiple" use="required"/>
                    <xs:attribute name="ValidFormat" use="required">
                         <xs:simpleType>
                              <xs:restriction base="xs:string">
                                   <xs:enumeration value="Opened"/>
                                   <xs:enumeration value="Updated"/>
                                   <xs:enumeration value="Solved"/>
                                   <xs:enumeration value="Closed"/>
                                   <xs:enumeration value="Inactive"/>
                                <xs:enumeration value="Opened/Closed"/>
                                   <xs:enumeration value="Cancelled"/>
                                   <xs:enumeration value="Superseded"/>
                                   <xs:enumeration value="Reopened"/>
                              </xs:restriction>

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                         </xs:simpleType>
                    </xs:attribute>
                    <xs:attribute name="Mandatory"
  type="xs:string" default="Yes"/>
               </xs:extension>
         </xs:simpleContent>
    </xs:complexType>
    <!--
  ==============================================================
  == Additional_Data Class                                    ==
  ==============================================================
    -->
    <xs:element name="Additional_Data"
  type="nttdm:Additional_DataType"/>
    <xs:complexType name="Additional_DataType">
         <xs:simpleContent>
               <xs:extension base="xs:string">
                    <xs:attribute name="Description"
  type="xs:string" fixed="Additional information"/>
                    <xs:attribute name="Type" type="nttdm:Free"
  use="optional"/>
                    <xs:attribute name="Valid_Format"
  type="xs:string" use="optional"/>
                    <xs:attribute name="Mandatory"
  type="xs:string" default="No"/>
               </xs:extension>
         </xs:simpleContent>
    </xs:complexType>
    <!--
  ===============================================================
  == Related_Activity Class                                    ==
  ===============================================================
    -->
    <xs:element name="Related_Activity"
  type="nttdm:Related_ActivityType"/>
    <xs:complexType name="Related_ActivityType">
         <xs:simpleContent>
               <xs:extension base="xs:string">
                    <xs:attribute name="Description"
  type="xs:string" fixed="The TT IDs of the related incidents"/>
                    <xs:attribute name="Type"
  type="nttdm:Multiple" use="optional"/>
                    <xs:attribute name="Valid_Format"
  type="xs:string" use="optional"/>
                    <xs:attribute name="Mandatory"
  type="xs:string" default="No"/>
                    </xs:extension>

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         </xs:simpleContent>
    </xs:complexType>
    <!--
  ===============================================================
  == History Class                                             ==
  ===============================================================
    -->
    <xs:element name="History" type="nttdm:HistoryType"/>
    <xs:complexType name="HistoryType">
         <xs:simpleContent>
               <xs:extension base="xs:string">
                    <xs:attribute name="Description"
  type="xs:string" fixed="The necessary Actions/events log"/>
                    <xs:attribute name="Type" type="nttdm:Free"
  use="required"/>
                    <xs:attribute name="Valid_Format"
  type="xs:string" use="required"/>
                    <xs:attribute name="Mandatory"
  type="xs:string" default="Yes"/>
               </xs:extension>
         </xs:simpleContent>
    </xs:complexType>
    <!--
  ===============================================================
  == Hash Class                                                ==
  ===============================================================
    -->
    <xs:element name="Hash" type="nttdm:HashType"/>
    <xs:complexType name="HashType">
         <xs:simpleContent>
               <xs:extension base="xs:string">
                    <xs:attribute name="Description"
  type="xs:string" fixed="Encrypted message hash"/>
                    <xs:attribute name="Type" type="nttdm:Defined"
  use="optional"/>
                    <xs:attribute name="Valid_Format"
  type="xs:string" use="optional"/>
                    <xs:attribute name="Mandatory"
  type="xs:string" default="No"/>
               </xs:extension>
         </xs:simpleContent>
    </xs:complexType>
<!--
  ===============================================================
  == TT_Source Class                                           ==
  ===============================================================
    -->

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<xs:element name="TT_Source" type="nttdm:TT_SourceType"/>
    <xs:complexType name="TT_SourceType">
         <xs:simpleContent>
               <xs:extension base="xs:string">
                    <xs:attribute name="Description"
  type="xs:string" fixed="The source of the ticket"/>
                    <xs:attribute name="Type"
  type="nttdm:Multiple" use="optional"/>
                    <xs:attribute name="ValidFormat"
  use="optional">
                         <xs:simpleType>
                              <xs:restriction base="xs:string">
                                   <xs:enumeration value="Users"/>
                                   <xs:enumeration
  value="Monitoring"/>
                                   <xs:enumeration value="Other NOC"/>
                              </xs:restriction>
                         </xs:simpleType>
                    </xs:attribute>
                    <xs:attribute name="Mandatory"
  type="xs:string" default="No"/>
               </xs:extension>
         </xs:simpleContent>
    </xs:complexType>
    <!--
  ===============================================================
  == Affected_Community Class                                  ==
  ===============================================================
    -->
    <xs:element name="Affected_Community"
  type="nttdm:Affected_CommunityType"/>
    <xs:complexType name="Affected_CommunityType">
         <xs:simpleContent>
               <xs:extension base="xs:string">
                    <xs:attribute name="Description"
  type="xs:string" fixed="The community that was affected by the
  trouble incident"/>
    <xs:attribute name="Type" type="nttdm:Free" use="optional"/>
                    <xs:attribute name="Valid_Format"
  type="xs:string" use="optional"/>
                    <xs:attribute name="Mandatory"
  type="xs:string" default="No"/>
               </xs:extension>
         </xs:simpleContent>
    </xs:complexType>



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<!--
  ===============================================================
  == Affected_Service Class                                    ==
  ===============================================================
    -->
    <xs:element name="Affected_Service"
  type="nttdm:Affected_ServiceType"/>
    <xs:complexType name="Affected_ServiceType">
         <xs:simpleContent>
               <xs:extension base="xs:string">
                    <xs:attribute name="Description"
  type="xs:string" fixed="The service that was affected by the
  trouble incident"/>
                    <xs:attribute name="Type"
  type="nttdm:Multiple" use="optional"/>
                    <xs:attribute name="ValidFormat"
  type="xs:string" use="optional"/>
                    <xs:attribute name="Mandatory"
  type="xs:string" default="No"/>
               </xs:extension>
         </xs:simpleContent>
    </xs:complexType>
    <!--
  ===============================================================
  == Data Types                                                ==
  ===============================================================
    -->
    <xs:simpleType name="Defined">
         <xs:restriction base="xs:string"/>
    </xs:simpleType>
    <xs:simpleType name="Free">
          <xs:restriction base="xs:string"/>
     </xs:simpleType>
     <xs:simpleType name="Multiple">
          <xs:restriction base="xs:string"/>
     </xs:simpleType>
     <xs:simpleType name="List">
          <xs:restriction base="xs:string"/>
     </xs:simpleType>
  </xs:schema>









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7. Security Considerations

   Some security issues should be kept in mind as network TTs
   could carry sensitive information (IP addresses, contact
   details, authentication details, commercial providers involved
   etc.) about flagship institutions (military, health centre...).

   o  Integrity: The HASH field is intended to ensure integrity of
      received tickets.

   o  Confidentiality: could be ensured by encrypting whole tickets
      or only some parts. This could allow having meaningful
      tickets to be disclosed while only sensitive information
      protected.

   o  Peer entity authentication: message sender authentication must
      be provided in order to establish session with data origin 
      authentication regardless of the form in which the TTs are
      exchanged, being either delivered through email, web forms or
      through a SOAP service. The latter is considered the better choice,
      the model itself though does not specify the communications
      requirements.

8. IANA Considerations

   This document uses URNs to describe an XML namespace and schema
   conforming to a registry mechanism described in [12]

   Registration for the NTTDM namespace:

     o  URI: urn:ietf:params:xml:ns:nttdm-1.0
     o  Registrant Contact: See the first author of the "Author's
        Address" section of this document.
     o  XML: None.  Namespace URIs do not represent an XML 
        specification.

     Registration for the NTTDM XML schema:

     o  URI: urn:ietf:params:xml:schema:nttdm-1.0
     o  Registrant Contact: See the first author of the "Author's 
        Address" section of this document.
     o  XML: See the "NTTDM Schema" in Section 8 of this document.






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9. Acknowledgements

   The following groups and individuals contributed substantially
   to this document and are gratefully acknowledged:

   - Rodwell Toby, Apted Emma, DANTE

   - Allocchio Claudio, Vuagnin Gloria, Battista Claudia, GARR

   - Schauerhammer Karin, Stoy Robert, DFN

10. List of acronyms

   TT:    Trouble Ticket

   NTTDM: Network Trouble Ticket Data Model

   DB:    Data Base

   EGEE:  Enabling Grid for E-sciencE

   ENOC:  EGEE NOC

   NOC:   Network Operation Centre

   GOC:   Grid Operation Centre

   NREN:  National Research and Educational Networks

   QoS:   Quality of service

   SLA:   Service level Agreement

   UML:   Unified Modeling Language

   XML:   Extensible Markup Language












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11. References

   [1]  http://www.eu-egee.org/

   [2]  http://en.wikipedia.org/wiki/Quality of service

   [3]  http://en.wikipedia.org/wiki/Service Level Agreement

   [4]  http://egee-sa2.web.cern.ch/egee-sa2/ENOC.html

   [5]  Rumbaugh, J., Jacobson, I., and G. Booch, "The Unified
        Modeling Language Reference Model," ISBN 020130998X,
        Addison-Wesley, 1998.

   [6]  World Wide Web Consortium, "Extensible Markup Language
        (XML) 1.0 (Second Edition)", W3C Recommendation, 
        October 2000,
        <http://www.w3.org/TR/2000/REC-xml-20001006>.

   [7]  XML Schema Part 0: Primer, W3C Recommendation, 2 May 2001.
        http://www.w3.org/TR/xmlschema-0/

   [8]  World Wide Web Consortium, "XML XML Schema Part 1:
        Structures Second Edition", W3C Recommendation, 
        October 2004,
        <http://www.w3.org/TR/xmlschema-1/>.

   [9]  World Wide Web Consortium, "XML Schema Part 2: Datatypes
        Second Edition", W3C Recommendation, October 2004,
        <http://www.w3.org/TR/xmlschema-2/>.

   [10] World Wide Web Consortium, "Namespaces in XML", W3C
        Recommendation, January 1999, 
        <http://www.w3.org/TR/REC-xml-names/>.

   [11] http://www.ietf.org/rfc/rfc1297.txt

   [12] Mealling, M., "The IETF XML Registry", RFC 3688, January
        2004.









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12. Authors' Addresses

  Dimitris Zisiadis
  Centre for Research and Technology
  6th km Thermi-Thessaloniki, 57001
  Hellas

  Email: dzisiadis@iti.gr


  Spyros Kopsidas
  Centre for Research and Technology
  6th km Thermi-Thessaloniki, 57001
  Hellas

  Email: spyros@uth.gr


  Matina Tsavli
  Centre for Research and Technology
  6th km Thermi-Thessaloniki, 57001
  Hellas


  Email: sttsavli@uth.gr


  Leandros Tassiulas
  Centre for Research and Technology
  6th km Thermi-Thessaloniki, 57001
  Hellas

  Email: leandros@uth.gr


  Chrysostomos Tziouvaras
  Greek Research and Technology Network
  56, Mesogion Av. 11527, Athens
  Hellas

  Email: tziou@grnet.gr






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  Guillaume Cessieux
  Computer Centre of National Institute for Nuclear Physics and
  Particle
  Physics (IN2P3-CC) - France

  Email: Guillaume.Cessieux@cc.in2p3.fr


  Xavier Jeannin
  National Centre for Scientific Research
  Network Unit - UREC - France

  Email: Xavier.Jeannin@urec.cnrs.fr


