NETMOD Working Group S. Mansfield, Ed.
Internet-Draft Ericsson Inc.
Intended status: Informational B. Zeuner
Expires: March 11, 2016 Deutsche Telekom AG
N. Davis
Ciena
X. Yun
Fiberhome
Y. Tochio
Fujitsu
K. Lam
E. Varma
Alcatel Lucent
September 8, 2015

Guidelines for Translation of UML Information Model to YANG Data Model
draft-mansfield-netmod-uml-to-yang-01

Abstract

This document defines guidelines for translation of data modeled with UML to YANG including mapping of object classes, attributes, data types, associations, interfaces, operations and operation parameters, notifications, and lifecycle.

Status of This Memo

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This Internet-Draft will expire on March 11, 2016.

Copyright Notice

Copyright (c) 2015 IETF Trust and the persons identified as the document authors. All rights reserved.

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Table of Contents

1. Introduction

As discussed in draft-lam-teas-usage-info-model-net-topology [I-D.lam-teas-usage-info-model-net-topology] a Data Model (DM) may be derived from an Information Model (IM). However, in order to assure a consistent and valid data modelling language representation that enables maximum interoperability, translation guidelines are required. A set of translation rules also assists in development of automated tooling.

This draft defines guidelines for translation of data modelled with UML [OMG-UML-2.4] (as constrained by the ONF's UML Modeling Guidelines [ONF-TR-514]) to YANG (defined in RFC6020 [RFC6020] and YANG Update [I-D.ietf-netmod-rfc6020bis]) including mapping of object classes, attributes, data types, associations, interfaces, operations and operation parameters, notifications, and lifecycle.

2. Terminology

The following terms are defined in RFC6020 [RFC6020]

The following terms are defined in UML 2.4 [OMG-UML-2.4]

3. Overview

This document defines translation rules for all constructs used in a UML based IM to a data model using YANG.

While some mapping rules are straightforward, an IM in UML uses some constructs that cannot be mapped directly to a DM using YANG and conventions are described to make the translation predictable. Additionally, in some cases multiple mapping approaches are possible and selection among these is also necessary to assure interoperability.

Mapping guidelines for these constructs are provided in the following sections.

4. Mapping Guidelines

4.1. Mapping Guideline Considerations

Where "??" is inserted in the table, it means that the specific mapping is for further study as it is either as yet unclear how to map the construct or that there are multiple ways of doing the mapping and a single one needs to be selected.

A table will be included summarizing constructs in UML that do not directly map to YANG and where in this draft the associated guidelines for mapping these constructs will be provided.

4.2. Mapping of Object Classes

   
+-------------------------------------------------------------------+
|       Object Class --> "list" statement (key property, multiple   |
|                           instances) or                           | 
|                        "container" statement (single instance) or |
|                        "grouping" statement                       | 
+-------------------------------------------------------------------+
| UML Artifact          | YANG Artifact         | Comment           |
+-------------------------------------------------------------------+
| documentation         | "description"         |                   |
|                       | substatement          |                   |
+-------------------------------------------------------------------+
| superclass(es)        | abstract: "grouping"  |                   |
|                       |not abstract:"augment"??                   |
+-------------------------------------------------------------------+
| abstract              | "grouping" statement  |                   |
+-------------------------------------------------------------------+
| objectCreationNotific-| "notification"        | Goes beyond the   |
| ation                 | statement             | simple "a notific-|
| [YES/NO/NA]           |                       | ation has to be   |
|                       |                       | sent": a tool can |
|                       |                       | construct the sig-|
|                       |                       | ature of the noti-|
|                       |                       | cation by reading |
|                       |                       | the created       |
|                       |                       | object.           |
+-------------------------------------------------------------------+
| objectDeletionNotific-| "notification"        | Goes beyond the   |
| ation                 | statement             | simple "a notific-|
| [YES/NO/NA]           |                       | ation has to be   |
|                       |                       | sent": a tool can |
|                       |                       | construct the sig-|
|                       |                       | ature of the noti-|
|                       |                       | cation by reading |
|                       |                       | the deleted       |
|                       |                       | object. (i.e. not |
|                       |                       | necessary to      |
|                       |                       | provide the       |
|                       |                       | attributes of the |
|                       |                       | deleted object.   |
+-------------------------------------------------------------------+
| support               | "if-feature"          | Support and       |
|                       | substatement          | condition belong  |
+-----------------------+                       | together. If the  |
| condition             |                       | "support" is cond-|
|                       |                       | itional, then the |
|                       |                       | "condition"       |
|                       |                       | explains the cond-|
|                       |                       | itions under which|
|                       |                       | the class has to  |
|                       |                       | be supported.     |
+-------------------------------------------------------------------+
| operation             | "action"              | YANG 1.0 supports |
|                       | substatement          | only rpc -> add   |
|                       |                       | prefix to the rpc |
|                       |                       | name; i.e.        |
|                       |                       | objectClass::rpc; |
|                       |                       | "action" requires |
|                       |                       | YANG 1.1          |
+-------------------------------------------------------------------+
| XOR                   | "choice"              |                   |
|                       | substatement          |                   |
+-------------------------------------------------------------------+
| constraints between   | "must" substatement   |                   |
| attribute values ->   |                       |                   |
| error notfication??   |                       |                   |
| OCL??                 |                       |                   |
+-------------------------------------------------------------------+
| object identifier     | list::"key"           |                   |
|                       | substatement          |                   |
+-------------------------------------------------------------------+
| muliplicity on        | list::"min-elements"  | min-elements      |
| association           | "max-elements"        |  default = 0      |
|                       | substatements         | max-elements      |
|                       |                       |  default=unbounded|
|                       |                       | mandatory         |
|                       |                       |  default=false    |
+-------------------------------------------------------------------+
| Conditional PACs      | container::presence"  |                   |
|                       | substatement          |                   |
+-------------------------------------------------------------------+
| hyperlink??           | "reference"           | Papyrus doesn't   |
|                       | substatement          | support hyperlinks|
+-------------------------------------------------------------------+
| lifecycle stereotypes | "status"              | "current"         |
|                       | substatement          | "deprecated"      |
|                       |                       | "obsolete"        |
|                       |                       |  default="current"|
+-------------------------------------------------------------------+
| constraint property   | list::"unique"        |                   |
|                       | substatement          |                   |
+-------------------------------------------------------------------+
| complex attribute     | "uses" substatement   | use of a complex  |
|                       |                       | data type as the  |
|                       |                       | type of the       |
|                       |                       | attribute; e.g.,  |
|                       |                       | date and time,    |
|                       |                       | object creation   |
|                       |                       | data              |
+-------------------------------------------------------------------+
| {<constraint>}        | "when" substatement   |                   |
+-------------------------------------------------------------------+

Figure 1: Mapping of Object Classes


Figure 2: Example of Abstract Object Class Mapping (Available in PDF or HTML versions)


Figure 3: Example of Non-Abstract Object Class Mapping (Available in PDF or HTML versions)

4.3. Mapping of Attributes

+-------------------------------------------------------------------+
|       Attribute --> "leaf" (single) or "leaf list" (multiple)     |
|                        statement                                  |
+-------------------------------------------------------------------+
| UML Artifact          | YANG Artifact         | Comment           |
+-------------------------------------------------------------------+
| documentation         | "description"         |                   |
|                       | substatement          |                   |
+-------------------------------------------------------------------+
| type                  | "type" substatement   |                   |
|                       | (built-in or derived) |                   |
+-------------------------------------------------------------------+
| readOnly              | "config" substatement | config            |
|                       | (false)               | default = true    |
+-------------------------------------------------------------------+
| isOrdered             | "ordered-by"          | ordered-by        |
|                       | substatement          | default = system  |
|                       |("system" or "user")   |                   |
+-------------------------------------------------------------------+
| multiplicity          | "mandatory" or        | min-elements      |
|                       | "min-elements" and    |  default = 0      |
|                       | "max-elements"        | max-elements      |
|                       | substatements         |  default=unbounded|
|                       | [0..1]=>no mapping    | mandatory         |
|                       |   needed; is default  |  default=false    |
|                       |   substatement=false  |                   |
|                       | [1]=>mandatory        |                   |
|                       |   substatement=true   |                   |
|                       | [0..x]=> no mapping   |                   |
|                       |   needed; is default  |                   |
|                       | [1..x]=> min-elements |                   |
|                       |   substatement = 1    |                   |
|                       | [0..3]=> max-elements |                   |
|                       |   substatement = 3    |                   |
+-------------------------------------------------------------------+
| defaultValue          | "default"             | If a default value|
|                       | substatement          | exists and it is  |
|                       |                       | the desired value,|
|                       |                       | the parameter does|
|                       |                       | not have to be    |
|                       |                       | explicitly config-|
|                       |                       | ured by the user. |
+-------------------------------------------------------------------+
| isInvariant           | "extension"           |                   |
|                       | substatement ->       |                   |
|                       | ompExt:isInvariant    |                   |
+-------------------------------------------------------------------+
| valueRange            | "range" or "length"   |                   |
|                       | substatement of "type"|                   |
|                       | substatement          |                   |
+-------------------------------------------------------------------+
| passedByReference     | if passedByReference =| Relevant only to  |
|                       | true -> type leafref {| attributes that   |
|                       | path "/<object>/      | have an object    |
|                       | <objectidentifier>"}  | class defined as  |
|                       |                       | their type.       |
|                       | if passedByReference =|                   |
|                       | false -> either "list"|                   |
|                       | statement (key        |                   |
|                       | property, multiple    |                   |
|                       | instances) or         |                   |
|                       | "container" statement(|                   |
|                       | single instance)      |                   |
+-------------------------------------------------------------------+
| support               | "if-feature"          | Support and       |
|                       | substatement          | condition belong  |
+-----------------------+                       | together. If the  |
| condition             |                       | "support" is cond-|
|                       |                       | itional, then the |
|                       |                       | "condition"       |
|                       |                       | explains the cond-|
|                       |                       | itions under which|
|                       |                       | the class has to  |
|                       |                       | be supported.     |
+-------------------------------------------------------------------+
| error notfication??   | "must"                |                   |
|                       | substatement          |                   |
+-------------------------------------------------------------------+
| hyperlink??           | "reference"           | Papyrus doesn't   |
|                       | substatement          | support hyperlinks|
+-------------------------------------------------------------------+
| lifecycle stereotypes | "status"              | "current"         |
|                       | substatement          | "deprecated"      |
|                       |                       | "obsolete"        |
|                       |                       |  default="current"|
+-------------------------------------------------------------------+
| unit??                | "units" substatement  |                   |
+-------------------------------------------------------------------+
| {<constraint>}        | "when" substatement   |                   |
+-------------------------------------------------------------------+

Figure 4: Mapping of Attributes


Figure 5: Example of Attribute Mapping (Available in PDF or HTML versions)

4.4. Mapping of Types

+-------------------------------------------------------------------+
|                             Types                                 |
+-------------------------------------------------------------------+
| UML Artifact          | YANG Artifact         | Comment           |
+-------------------------------------------------------------------+
| Primitive Type        | Built-In Type if      | e.g., Integer     |
|                       | defined; otherwise ?? |new built-in type??|
+-------------------------------------------------------------------+
| Enumeration           | "enum" statement      |                   |
+-------------------------------------------------------------------+
| Basic Data Type       | "typeDef" statement   | e.g., MAC address,|
|                       |                       | IPv4 Address      |
+-------------------------------------------------------------------+
| Complex Data Type     | "grouping" statement  | e.g., date-time   |
|                       |                       | object creation   |
|                       |                       |  data             |
+-------------------------------------------------------------------+

Figure 6: Mapping of Types

Note: YANG allows also in-line enumerations which are not possible in UML

4.4.1. Mapping of Primitive Types

+-------------------------------------------------------------------+
|               Primitive Type -> new built-in type??               |
+-------------------------------------------------------------------+
| UML Artifact          | YANG Artifact         | Comment           |
+-------------------------------------------------------------------+
| documentation         | ??                    |                   |
+-------------------------------------------------------------------+

Figure 7: Mapping of Primitive Types

4.4.2. Mapping of Enumeration Types

+-------------------------------------------------------------------+
|               Enumeration Type -> "enum" statement                |
+-------------------------------------------------------------------+
| UML Artifact          | YANG Artifact         | Comment           |
+-------------------------------------------------------------------+
| documentation         | "description"         |                   |
|                       | substatement          |                   |
+-------------------------------------------------------------------+
| literal name          | "value"               |                   |
|                       | substatement          |                   |
+-------------------------------------------------------------------+
| hyperlink??           | "reference"           | Papyrus doesn't   |
|                       | substatement          | support hyperlinks|
+-------------------------------------------------------------------+
| lifecycle stereotypes | "status"              | "current",        |
|                       | substatement          | "deprecated",     |
|                       |                       | "obsolete"        |
|                       |                       | default=current   |
+-------------------------------------------------------------------+
| ??                    | "if-feature" statement|                   |
+-------------------------------------------------------------------+

Figure 8: Mapping of Enumeration Types


Figure 9: Example of Enumeration Type Mapping (Available in PDF or HTML versions)

4.4.3. Mapping of Basic Data Types

+-------------------------------------------------------------------+
|               Basic Data Type -> "typeDef" statement              |
+-------------------------------------------------------------------+
| UML Artifact          | YANG Artifact         | Comment           |
+-------------------------------------------------------------------+
| documentation         | "description"         |                   |
|                       | substatement          |                   |
+-------------------------------------------------------------------+
| type                  | "type" substatement   |                   |
|                       | (built-in type)       |                   |
+-------------------------------------------------------------------+
| defaultValue          | "default"             | If a default value|
|                       | substatement          | exists and it is  |
|                       |                       | the desired value,|
|                       |                       | the parameter does|
|                       |                       | not have to be    |
|                       |                       | explicitly config-|
|                       |                       | ured by the user. |
+-------------------------------------------------------------------+
| hyperlink??           | "reference"           | Papyrus doesn't   |
|                       | substatement          | support hyperlinks|
+-------------------------------------------------------------------+
| lifecycle stereotypes | "status"              | "current",        |
|                       | substatement          | "deprecated",     |
|                       |                       | "obsolete"        |
|                       |                       | default=current   |
+-------------------------------------------------------------------+
| unit??                | "units" statement     |                   |
+-------------------------------------------------------------------+

Figure 10: Mapping of Basic Data Types


Figure 11: Example of Basic Data Type Mapping (Available in PDF or HTML versions)

4.4.4. Mapping of Complex Data Types

+-------------------------------------------------------------------+
|               Complex Data Type -> "grouping" statement           |
+-------------------------------------------------------------------+
| UML Artifact          | YANG Artifact         | Comment           |
+-------------------------------------------------------------------+
| documentation         | "description"         |                   |
|                       | substatement          |                   |
+-------------------------------------------------------------------+
| not used              | "action" substatement |                   |
+-------------------------------------------------------------------+
| XOR                   | "choice"              |                   |
|                       | substatement          |                   |
+-------------------------------------------------------------------+
| hyperlink??           | "reference"           | Papyrus doesn't   |
|                       | substatement          | support hyperlinks|
+-------------------------------------------------------------------+
| lifecycle stereotypes | "status"              | "current",        |
|                       | substatement          | "deprecated",     |
|                       |                       | "obsolete"        |
|                       |                       | default=current   |
+-------------------------------------------------------------------+
| complex attribute     | "uses" statement      |                   |
+-------------------------------------------------------------------+

Figure 12: Mapping of Complex Data Types


Figure 13: Example of Complex Data Type Mapping (Available in PDF or HTML versions)

4.5. Mapping of Associations

+-------------------------------------------------------------------+
|                          Associations                             |
+-------------------------------------------------------------------+
| UML Artifact          | YANG Artifact         | Comment           |
+-------------------------------------------------------------------+
| Inheritance           | "grouping" or         | Multiple          |
|                       | "augment" statement   | inheritance can   |
|                       |                       | also be mapped    |
|                       |                       | using "groupings" |
|                       |                       | Need to define    |
|                       |                       | when augment is   |
|                       |                       | used.  Note:      |
|                       |                       | Augmentation can  |
|                       |                       | be conditional.   |
+-------------------------------------------------------------------+
| Composition with      | "container" statement | How to map "passed|
| "passed by value"     | containing "list"     | by reference"??   |
|                       | statement(s) (multiple|                   |
|                       | contained instances)  |                   |
|                       | or "container" state- |                   |
|                       | ment(s) (single       |                   |
|                       | contained instances)  |                   |
+-------------------------------------------------------------------+
| Aggregation with      | "leafref" statement   | How to map "passed|
| "passed by reference" |                       | by value"??       |
+-------------------------------------------------------------------+

Figure 14: Mapping of Associations


Figure 15: Association Mapping Example 1 (Available in PDF or HTML versions)


Figure 16: Association Mapping Example 2 (Available in PDF or HTML versions)


Figure 17: Association Mapping Example 3 (Available in PDF or HTML versions)

4.6. Mapping of Interfaces

+-------------------------------------------------------------------+
|                     UML Interface -> Container??                  |
+-------------------------------------------------------------------+
| documentation         | "description"         |                   |
|                       | substatement          |                   |
+-------------------------------------------------------------------+
| abstract              | ??                    |                   |
+-------------------------------------------------------------------+
| support               | "if-feature"          | Support and       |
|                       | substatement          | condition belong  |
+-----------------------+                       | together. If the  |
| condition             |                       | "support" is cond-|
|                       |                       | itional, then the |
|                       |                       | "condition"       |
|                       |                       | explains the cond-|
|                       |                       | itions under which|
|                       |                       | the class has to  |
|                       |                       | be supported.     |
+-------------------------------------------------------------------+

Figure 18: Mapping of Interfaces (grouping of operations

4.7. Mapping of Operations

+-------------------------------------------------------------------+
|             Operation -> "action" and "rpc" statements            |
| (RFC 6020:  The difference between an action and an rpc is that an|
| action is tied to a node in the data tree, whereas an rpc is      |
| associated at the module level.)                                  |
+-------------------------------------------------------------------+
| documentation         | "description"         |                   |
|                       | substatement          |                   |
+-------------------------------------------------------------------+
| pre-condition         | "extension"           | RFC 6020; During  |
|                       | substatement ->       | the NETCONF       |
|                       | ompExt:preCondition   | <edit-config> pro-|
|                       |                       | cessing errors are|
|                       |                       | already sent for: |
|                       |                       | - Delete requests |
|                       |                       |   for non-existent|
|                       |                       |   data.           |
|                       |                       | - Create requests |
|                       |                       |   for existing    |
|                       |                       |   data.           |
|                       |                       | - Insert requests |
|                       |                       |   with "before" or|
|                       |                       |   "after" para-   |
|                       |                       |   meters that do  |
|                       |                       |   not exist.      |
+-------------------------------------------------------------------+
| post-condition        | "extension"           |                   |
|                       | substatement          |                   |
|                       | ompExt:postCondition  |                   |
+-------------------------------------------------------------------+
| input parameter       | "input" substatement  |                   |
+-------------------------------------------------------------------+
| output parameter      | "output" substatement |                   |
+-------------------------------------------------------------------+
| operation exceptions  | "extension"           |                   |
|                       | substatement          |                   |
|                       | ompExt:operationExceptions                |
+-------------------------------------------------------------------+
| isOperationIdempotent | "extension"           |                   |
|                       | substatement          |                   |
|                       | ompExt:isOperationIdempotent              |
+-------------------------------------------------------------------+
| isAtomic              | "extension"           | Necessary?? Not in|
|                       | substatement          | UML Guidelines    |
|                       | ompExt:isAtomic       | (TR-514); needs to|
|                       |                       | be added??        |
+-------------------------------------------------------------------+
| support               | "if-feature"          | Support and       |
|                       | substatement          | condition belong  |
+-----------------------+                       | together. If the  |
| condition             |                       | "support" is cond-|
|                       |                       | itional, then the |
|                       |                       | "condition"       |
|                       |                       | explains the cond-|
|                       |                       | itions under which|
|                       |                       | the class has to  |
|                       |                       | be supported.     |
+-------------------------------------------------------------------+
| hyperlink??           | "reference"           | Papyrus doesn't   |
|                       | substatement          | support hyperlinks|
+-------------------------------------------------------------------+
| lifecycle stereotypes | "status"              | "current",        |
|                       | substatement          | "deprecated",     |
|                       |                       | "obsolete"        |
|                       |                       | default=current   |
+-------------------------------------------------------------------+

Figure 19: Mapping of Operations


Figure 20: Operation Mapping Example (Available in PDF or HTML versions)

4.8. Mapping of Operation Parameters

+-------------------------------------------------------------------+
|                      Operation Parameters                         |
+-------------------------------------------------------------------+
| documentation         | "description"         |                   |
|                       | substatement          |                   |
+-------------------------------------------------------------------+
| direction             | "input" or "output"   |                   |
|                       | substatement          |                   |
+-------------------------------------------------------------------+
| type                  | see mapping of        |                   |
+-----------------------| attribute types       |-------------------+
| isOrdered             | (grouping, leaf,      |                   |
+-----------------------|  leaf-list, list,     |-------------------+
| multiplicity          |  typedef, uses)       |                   |
+-----------------------|                       |-------------------+
| defaultValue          |                       |                   |
+-----------------------|                       |-------------------+
| valueRange            |                       |                   |
+-------------------------------------------------------------------+
| passedByReference     | if passedByReference =| Relevant only to  |
|                       | true -> type leafref {| attributes that   |
|                       | path "/<object>/      | have an object    |
|                       | <objectidentifier>"}  | class defined as  |
|                       |                       | their type.       |
|                       | if passedByReference =|                   |
|                       | false -> either "list"|                   |
|                       | statement (key        |                   |
|                       | property, multiple    |                   |
|                       | instances) or         |                   |
|                       | "container" statement(|                   |
|                       | single instance)      |                   |
+-------------------------------------------------------------------+
| support               | "if-feature"          | Support and       |
|                       | substatement not      | condition belong  |
+-----------------------+ defined for input and | together. If the  |
| condition             | output substatements  | "support" is cond-|
|                       | in YANG??             | itional, then the |
|                       |                       | "condition"       |
|                       |                       | explains the cond-|
|                       |                       | itions under which|
|                       |                       | the class has to  |
|                       |                       | be supported.     |
+-------------------------------------------------------------------+
| XOR                   | "choice"              |                   |
|                       | substatement          |                   |
+-------------------------------------------------------------------+
| error notification??  | "must"                |                   |
|                       | substatement          |                   |
+-------------------------------------------------------------------+
| complex parameter     | "uses"                |                   |
|                       | substatement          |                   |
+-------------------------------------------------------------------+

Figure 21: Mapping of Operation Parameters


Figure 22: Parameter Mapping Example (Available in PDF or HTML versions)

4.9. Mapping of Notifications

+-------------------------------------------------------------------+
|                 Signal -> "notification" statement                |
+-------------------------------------------------------------------+
| documentation         | "description"         |                   |
|                       | substatement          |                   |
+-------------------------------------------------------------------+
| support               | "if-feature"          | Support and       |
|                       | substatement          | condition belong  |
+-----------------------+                       | together. If the  |
| condition             |                       | "support" is cond-|
|                       |                       | itional, then the |
|                       |                       | "condition"       |
|                       |                       | explains the cond-|
|                       |                       | itions under which|
|                       |                       | the class has to  |
|                       |                       | be supported.     |
+-------------------------------------------------------------------+
| XOR                   | "choice"              |                   |
|                       | substatement          |                   |
+-------------------------------------------------------------------+
| error notification??  | "must"                |                   |
|                       | substatement          |                   |
+-------------------------------------------------------------------+
| hyperlink??           | "reference"           | Papyrus doesn't   |
|                       | substatement          | support hyperlinks|
+-------------------------------------------------------------------+
| lifecycle stereotypes | "status"              | "current",        |
|                       | substatement          | "deprecated",     |
|                       |                       | "obsolete"        |
|                       |                       | default=current   |
+-------------------------------------------------------------------+
| attributes            | see mapping of        |                   |
|                       | attribute types       |                   |
|                       | (grouping, leaf,      |                   |
|                       |  leaf-list, container,|                   |
|                       |  list, typedef, uses) |                   |
+-------------------------------------------------------------------+
| complex attribute     | "uses"                |                   |
|                       | substatement          |                   |
+-------------------------------------------------------------------+

Figure 23: Mapping of Notifications


Figure 24: Notification Mapping Example (Available in PDF or HTML versions)

4.10. Mapping of Lifecycle

+-------------------------------------------------------------------+
|                          UML Lifecycle                            |
+-------------------------------------------------------------------+
| lifecycle stereotypes | "status"              | YANG: "current",  |
|                       | substatement          | "deprecated",     |
|                       |                       | "obsolete"        |
|                       |                       | default=current   |
|                       |                       |                   |
|                       |                       | UML: <<Example>>, |
|                       |                       | <<Experimental>>, |
|                       |                       | <<Faulty>>,       |
|                       |                       | <<Preliminary>>,  |
|                       |                       | <<Obsolete>>,     |
|                       |                       | <<LikelyToChange>>|
|                       |                       |                   |
|                       |                       | How to map or     |
|                       |                       | enhance??         |
+-------------------------------------------------------------------+

Figure 25: Mapping of Lifecycle

4.11. Other Mappings

+-------------------------------------------------------------------+
|                          UML Lifecycle                            |
+-------------------------------------------------------------------+
| Conditional Package   | "container" statement |                   |
|                       | with                  |                   |
|                       | "presence"            |                   |
|                       | substatement          |                   |
+-------------------------------------------------------------------+
| Package??             | Submodule             |                   |
+-------------------------------------------------------------------+

Figure 26: Other Mappings

5. Mapping Issues

5.1. Using types defined in YANG

Many common types (primitive and complex) are already defined in YANG. E.g., ietf-inet-types, ietf-yang-types (others to be investigated):

ietf-inet-types
 - domain name and URI types                   - ietf-yang-types
   - DomainName                                 - Counter32
   - Uri                                        - Counter64
   - <<Union>> Host                             - DateAndTime
 - types related to IP addresses and hostnames  - DottedQuad
   - Ip4Address                                 - Gauge32
   - Ipv4AddressNoZone                          - Gauge64
   - Ipv4Prefix                                 - HexString
   - Ipv6Address                                - MacAddress
   - Ipv6AddressNoZone                          - ObjectIdentifier
   - Ipv6Prefix                                 - ObjectIdentifier128
   - <<Union>> IpAddress                        - PhysAddress
   - <<Union>> IpAddressNoZone                  - Timestamp
   - <<Union>> IpPrefix                         - Timeticks
 - types related to protocol fields             - Uuid
   - IpVersion                                  - Xpath1.0
   - DSCP                                       - YangIdentifier
   - IpV6FlowLabel                              - ZeroBasedCounter32
   - PortNumber                                 - ZeroBasedCounter64                           

Figure 27: Re-engineered Example

It is proposed to define for the commonly used YANG types corresponding UML primitive or complex data types respectively. These types will be available (by default) for use in all UML information models. This "re-engineering" needs to be done without making the UML models YANG-depended.


Figure 28: IP Address Mapping Examples (Available in PDF or HTML versions)

5.2. YANG 1.0 or YANG 1.1

YANG 1.0 is approved and defined in RFC6020 [RFC6020].

YANG 1.1 is not currently approved and its definition is ongoing in draft-ietf-netmod-rfc6020bis [I-D.ietf-netmod-rfc6020bis]. Main enhancements are the action and anydata statements.

5.3. Mapping of UML Packages

Need to define mapping rules for UML package into YANG modules or the new draft YANG package statement (draft-bierman-netmod-yang-package [I-D.bierman-netmod-yang-package])?

6. Mapping Patterns

6.1. UML Recursion

As YANG defines hierarchical data store, any instances that need to store recursive containment will require translation. A mapping between object-oriented store and a hierarchical store is possible; however, there is more than one option:

  • Reference Based Approach - have a flat list of objects, where the objects are linked into a hierarchy using references. An example of a two-way navigable approach is in RFC7223 [RFC7223]. See example in Figure 29 below.
  • Assume some specific number of "recursions"; i.e., specify some default number of recursion levels, and define a configurable parameter to allow changing the number of levels. See example in Figure 30 below, in which there is one level of recursion.


Figure 29: Reference Based Approach (Available in PDF or HTML versions)


Figure 30: Specific Number of Recusions (Available in PDF or HTML versions)

The reference-based approach is generally preferred because there is no arbitrary limitation set in the solution.

6.2. UML Conditional Pacs

May use the "presence" property of the container statement?


Figure 31: Mapping of Conditional Packages (Available in PDF or HTML versions)

6.3. XOR Relationship

Use the "choice" property of the container statement.

6.4. Mapping of UML Support and Condition

The UML Modeling Guidelines [ONF-TR-514] define support and condition for all UML artifacts (M - Mandatory, O - Optional, C - Conditional, CM - Conditional-Mandatory, CO - Conditional-Optional). Support qualifies the support of the artifact at the management interface. Condition contains the condition for the condition-related support qualifiers.

M - Mandatory maps to the "mandatory" substatement in choice and leaf or to the "min-elements" substatement in leaf-list and list.

O - Optional need not be mapped since the per default the "mandatory" and "min-elements" substaments define optional.

All conditional UML support qualifiers are mapped to the "if-feature" substatement.


Figure 32: Support and Condition Mapping Example (Available in PDF or HTML versions)

7. Mapping Basics

7.1. UML-YANG or XMI-YANG


Figure 33: Example UML to YANG Mapping (Available in PDF or HTML versions)


Figure 34: Example XMI (Papyrus) to YANG Mapping (Available in PDF or HTML versions)

8. Acknowledgements

9. IANA Considerations

This memo includes no request to IANA.

10. Security Considerations

This document defines defines guidelines for translation of data modeled with UML to YANG. As such, it doesn't contribute any new security issues beyond those discussed in Sec. 16 of RFC6020 [RFC6020].

11. Informative References

[1] Bjorklund, M., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, DOI 10.17487/RFC6020, October 2010.
[2] Bjorklund, M., "A YANG Data Model for Interface Management", RFC 7223, DOI 10.17487/RFC7223, May 2014.
[3] Bierman, A., "The YANG Package Statement", Internet-Draft draft-bierman-netmod-yang-package-00, July 2015.
[4] Bjorklund, M., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", Internet-Draft draft-ietf-netmod-rfc6020bis-06, July 2015.
[5] Galimberti, G., Kunze, R., Lam, H., Hiremagalur, D., Grammel, G., Fang, L. and G. Ratterree, "A YANG model to manage the optical interface parameters of "G.698.2 single channel" in DWDM applications", Internet-Draft draft-dharini-netmod-g-698-2-yang-04, July 2015.
[6] Lam, H., Varma, E., Doolan, P., Davis, N., Zeuner, B., Betts, M., Busi, I. and S. Mansfield, "Usage of IM for network topology to support TE Topology YANG Module Development", Internet-Draft draft-lam-teas-usage-info-model-net-topology-01, July 2015.
[7] OMG, "Unified Modeling Language (UML)", 2011.
[8] OMG, "ONF TR-514 v1.0 UML Modeling Guidelines", 2015.

Appendix A. Example

The YANG data schema (in tree format) shown below was extracted from dharini-netmod-g-698-2-yang [I-D.dharini-netmod-g-698-2-yang] and represents the same data as UML model appearing in Figure 37 after the tree format. Note: The color code used in the tree format corresponds to the color code used in the UML class diagram.


Figure 35: Interfaces Tree (Available in PDF or HTML versions)


Figure 36: Notifications Tree (Available in PDF or HTML versions)


Figure 37: Interfaces UML Model (Available in PDF or HTML versions)

Authors' Addresses

Scott Mansfield (editor) Ericsson Inc. USA Phone: +1 724 931 9316 EMail: scott.mansfield@ericsson.com
Bernd Zeuner Deutsche Telekom AG Heinrich-Hertz-Str, 3-7 Darmstadt, 64295 Germany Phone: +49 6151 58-12086 EMail: b.zeuner@telekom.de
Nigel Davis Ciena United Kingdom EMail: ndavis@ciena.com
Xiang Yun Fiberhome China EMail: yunxig@fiberhome.com.cn
Yuji Tochio Fujitsu Japan EMail: tochio@jp.fujitsu.com
Hing-Kam Lam Alcatel Lucent USA Phone: +1 732 331 3476 EMail: kam.lam@alcatel-lucent.com
Eve Varma Alcatel Lucent USA EMail: eve.varma@alcatel-lucent.com