Network Working Group B. Linowski Internet-Draft TCS/Nokia Siemens Networks Intended status: Experimental M. Ersue Expires: April 22, 2011 Nokia Siemens Networks S. Kuryla 360 Treasury Systems October 19, 2010 Extending YANG with Language Abstractions draft-linowski-netmod-yang-abstract-04 Abstract YANG - the NETCONF Data Modeling Language - supports modeling of a tree of data elements that represent the configuration and runtime status of a particular network element managed via NETCONF. This memo suggests to enhance YANG with supplementary modeling features and language abstractions with the aim to improve the model extensibility and reuse. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on April 22, 2011. Copyright Notice Copyright (c) 2010 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 (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect Linowski, et al. Expires April 22, 2011 [Page 1] Internet-Draft YANG Language Abstractions October 2010 to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Linowski, et al. Expires April 22, 2011 [Page 2] Internet-Draft YANG Language Abstractions October 2010 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.1. Key Words . . . . . . . . . . . . . . . . . . . . . . . . 5 1.2. Motivation . . . . . . . . . . . . . . . . . . . . . . . . 5 1.3. Modeling Improvements with Language Abstractions . . . . . 6 1.4. Design Approach . . . . . . . . . . . . . . . . . . . . . 8 1.5. Modeling Resource Models with YANG . . . . . . . . . . . . 8 1.5.1. Example of a Physical Network Resource Model . . . . . 8 1.5.2. Modeling Entity MIB Entries as Physical Resources . . 12 2. Complex Types . . . . . . . . . . . . . . . . . . . . . . . . 16 2.1. Definition . . . . . . . . . . . . . . . . . . . . . . . . 16 2.2. complex-type extension statement . . . . . . . . . . . . . 16 2.3. instance extension statement . . . . . . . . . . . . . . . 18 2.4. instance-list extension statement . . . . . . . . . . . . 19 2.5. extends extension statement . . . . . . . . . . . . . . . 20 2.6. abstract extension statement . . . . . . . . . . . . . . . 20 2.7. XML Encoding Rules . . . . . . . . . . . . . . . . . . . . 21 2.8. Type Encoding Rules . . . . . . . . . . . . . . . . . . . 21 2.9. Extension and Feature Definition Module . . . . . . . . . 22 2.10. Example Model for Complex Types . . . . . . . . . . . . . 25 2.11. NETCONF Payload Example . . . . . . . . . . . . . . . . . 26 2.12. Update Rules for Modules Using Complex Types . . . . . . . 29 2.13. Using Complex Types . . . . . . . . . . . . . . . . . . . 29 2.13.1. Overriding Complex Type Data Nodes . . . . . . . . . . 29 2.13.2. Augmenting Complex Types . . . . . . . . . . . . . . . 30 2.13.3. Controlling the Use of Complex Types . . . . . . . . . 31 3. Typed Instance Identifier . . . . . . . . . . . . . . . . . . 32 3.1. Definition . . . . . . . . . . . . . . . . . . . . . . . . 32 3.2. instance-type extension statement . . . . . . . . . . . . 32 3.3. Typed Instance Identifier Example . . . . . . . . . . . . 32 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 33 5. Security Considerations . . . . . . . . . . . . . . . . . . . 34 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 34 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 34 7.1. Normative References . . . . . . . . . . . . . . . . . . . 34 7.2. Informative References . . . . . . . . . . . . . . . . . . 35 Appendix A. Change Log . . . . . . . . . . . . . . . . . . . . . 35 A.1. 03-04 . . . . . . . . . . . . . . . . . . . . . . . . . . 35 A.2. 02-03 . . . . . . . . . . . . . . . . . . . . . . . . . . 36 A.3. 01-02 . . . . . . . . . . . . . . . . . . . . . . . . . . 36 A.4. 00-01 . . . . . . . . . . . . . . . . . . . . . . . . . . 37 Appendix B. YANG Modules for Physical Network Resource Model and Hardware Entities Model . . . . . . . . . . . . . 37 Appendix C. Example YANG Module for the IPFIX/PSAMP Model . . . . 44 C.1. Modeling Improvements for the IPFIX/PSAMP Model with Complex types and Typed instance identifiers . . . . . . . 44 C.2. IPFIX/PSAMP Model with Complex Types and Typed Linowski, et al. Expires April 22, 2011 [Page 3] Internet-Draft YANG Language Abstractions October 2010 Instance Identifiers . . . . . . . . . . . . . . . . . . . 45 Linowski, et al. Expires April 22, 2011 [Page 4] Internet-Draft YANG Language Abstractions October 2010 1. Introduction YANG - the NETCONF Data Modeling Language ([RFC6020]) - supports modeling of a tree of data elements that represent the configuration and runtime status of a particular network element managed via NETCONF. This document defines extensions for the modeling language YANG as new language statements, which introduce language abstractions to improve the model extensibility and reuse. A model example from an actual network management system is given to highlight the value of proposed language extensions, especially class inheritance and recursiveness. The language extensions defined in this document have been implemented with two open source tools. These tools have been used to validate the model examples through the document. 1.1. Key Words The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14, [RFC2119]. 1.2. Motivation o Many systems today have a management information base that in effect is organized as a tree build of recursively nested container nodes. For example, the physical resources in the ENTITY-MIB conceptually form a containment tree. The index entPhysicalContainedIn points to the containing entity in a flat list. The ability to represent nested, recursive data structures of arbitrary depth would enable the representation of the primary containment hierarchy of physical entities as a node tree in the server MIB and in the NETCONF payload. o A manager scanning the network in order to update the state of an inventory management system might be only interested in data structures that represent a specific type of hardware. Such a manager would then look for entities that are of this specific type, including those that are an extension or specialization of this type. To support this use case, it is helpful to bear the corresponding type information within the data structures, which describe the network element hardware. o A system that is managing network elements is concerned e.g. with managed objects of type "plug-in modules" that have a name, a version and an activation state. In this context, it is useful to define the "plug-in module" as a concept that is supposed to be further detailed and extended by additional concrete model Linowski, et al. Expires April 22, 2011 [Page 5] Internet-Draft YANG Language Abstractions October 2010 elements. In order to realize such a system, it is worth to model abstract entities, which enable reuse and ease concrete refinements of that abstract entity in a second step. o As particular network elements have specific type of components that need to be managed (OS images, plug-in modules, equipment, etc.), it should be possible to define concrete types, which describe the managed object precisely. By using type-safe extensions of basic concepts a system in the manager role can safely and explicitly determine that e.g. the "equipment" is actually of type "network card". o Currently different SDOs are working on the harmonization of their management information models. Often a model mapping or transformation between systems becomes necessary. The harmonization of the models is done e.g. by mapping of the two models on object level or integrating an object hierarchy into an existing information model. Extending YANG with language abstractions can simplify on the one hand the adoption of IETF resource models by other SDOs and facilitate the alignment with other SDO's resource models (e.g. TM Forum SID). The proposed YANG extensions can on the other hand enable the utilization of YANG modeling language in other SDOs, which are used to model complex management systems in a top-down manner and use high-level language features frequently. This memo specifies additional modeling features for the YANG language in the area of structured model abstractions, typed references as well as recursive data structures and discusses how these new features can improve the modeling capabilities of YANG. Section 1.5.1 contains a physical resource model, which deals with some of the modeling challenges illustrated above. Section 1.5.2 gives an example, which uses the base classes defined in the physical resource model and derives a model for physical entities defined in Entity MIB". 1.3. Modeling Improvements with Language Abstractions Complex Types and Typed Instance Identifiers provide various technical improvements on modeling level: o In case the model of a system that should be managed with NETCONF makes use of inheritance, complex types enable an almost one-to- one mapping between the classes in the original model and the YANG module. Linowski, et al. Expires April 22, 2011 [Page 6] Internet-Draft YANG Language Abstractions October 2010 o Typed instance identifiers allow representing associations between the concepts in a type-safe way to prevent type errors caused by referring to data nodes of incompatible types. This avoids referring to a particular location in the MIB, which is not mandated by the domain model. o Complex types allow defining complete, self-contained type definitions. It is not necessary to explicitly add a key statement to lists, which use a grouping defining the data nodes. o Complex types simplify concept refinement by extending a base complex type and make it superfluous to represent concept refinements with workarounds such as huge choice-statements with complex branches. o Abstract complex types ensure correct usage of abstract concepts by enforcing the refinement of common set of properties before instantiation. o Complex types allow defining recursive structures. This enables to represent complex structures of arbitrary depth by nesting instances of basic complex types that may contain themselves. o Complex types avoid introducing meta-data types (e.g. type code enumerations) and meta-data leafs (e.g. leafs containing a type code) to indicate, which concrete type of object is actually represented by a generic container in the MIB. This also avoids to explicitly rule out illegal use of sub-type specific properties in generic containers. o Complex type instances include the type information in the NETCONF payload. This allows to determine the actual type of an instance during the NETCONF payload parsing and avoids the use of additional leafs in the model, which provide the type information as content. o Complex types may be declared explicitly as optional features, which is not possible when the actual type of an entity represented by a generic container is indicated with a type code enumeration. Appendix C 'Example YANG Module for the IPFIX/PSAMP Model' lists technical improvements for modeling with Complex Types and Typed Instance Identifiers and exemplifies the usage of the proposed YANG extensions based on the IPFIX/PSAMP configuration model in [IPFIXCONF]. Linowski, et al. Expires April 22, 2011 [Page 7] Internet-Draft YANG Language Abstractions October 2010 1.4. Design Approach The proposed additional features for YANG in this memo are designed to reuse existing YANG statements whenever possible. Additional semantics is expressed by an extension that is supposed to be used as a substatement of an existing statement. The proposed features don't change the semantics of models that are valid with respect to the YANG specification [RFC6020]. 1.5. Modeling Resource Models with YANG 1.5.1. Example of a Physical Network Resource Model The diagram below depicts a portion of an information model for manageable network resources used in an actual network management system. Note: The referenced model (UDM, Unified Data Model) is based on key resource modelling concepts from [SID V8] and is compliant with selected parts of SID Resource Abstract Business Entities domain ([UDM]). The class diagram in Figure 1 and the according YANG module excerpt focus on basic resource ("Resource" and the distinction between logical- and physical resources) and hardware abstractions ("Hardware", "Equipment", and "EquipmentHolder"). Some class attributes were omitted to achieve decent readability. +--------+ |Resource| +--------+ /\ /\ -- -- | | | +---------------+ | |LogicalResource| | +---------------+ | | | | +--------+ | |Physical| +-----------+ '-|Resource|<|-+-|PhysicalLink| +---- ---+ | +------------+ | |0..* physicalLink | | | | equipment Linowski, et al. Expires April 22, 2011 [Page 8] Internet-Draft YANG Language Abstractions October 2010 | | Holder | | 0..* | | +-------+ | |0..* hardware | | | +--------+ +---------------+ +---------+ | '-|Hardware|<|-+-|ManagedHardware|<|-+-|Equipment|<>--+ +--------+ | +---------------+ | | Holder |0..1 <> | | +---------+ 0..1| | | <> | | | |0..* equipment | | | | Holder | | | | | | | |0..* equipment | | | | | | | | equipment | | | | 0..* | | | | +-------+ | | | | | | | | | +---------+ | | | '-|Equipment|<>--+ | | +---------+0..1 | | compositeEquipment | | | | +-----------------+ | '-|PhysicalConnector|----+0..* source '----------+-----------------+ | Physical physicalConnector 0..* | | Connector | | +-----------+ 0..* targetPhysicalConnector Figure 1: Physical Network Resource Model Since this model is an abstraction of network element specific MIB topologies, modeling it with YANG creates some challenges. Some of these challenges and how they can be addressed with complex types are explained below: o Modeling of abstract concepts: Classes like "Resource" represent concepts that primarily serve as a base class for derived classes. With complex types, such an abstract concept could be represented by an abstract complex type (see "complex-type extension statement" and "abstract extension statement"). o Class Inheritance: Information models for complex management domains often use class inheritance to create specialized classes Linowski, et al. Expires April 22, 2011 [Page 9] Internet-Draft YANG Language Abstractions October 2010 like "PhysicalConnector" from a more generic base class (here "Hardware"), which itself might inherit from another base class ("PhysicalResource") etc. Complex types allow creating enhanced versions of an existing (abstract or concrete) base type via an extension (see "extends extension statement"). o Recursive containment: In order to specify containment hierarchies models frequently contain different aggregation associations, in which the target (contained element) is either the containing class itself or a base class of the containing class. In the model above, the recursive containment of "EquipmentHolder" is an example of such a relationship. Complex types support such a containment by using a complex type (or one of its ancestor types) as type of an instance or instance list that is part of its definition (see "instance(-list) extension statement"). o Reference relationships: A key requirement on large models for network domains with many related managed objects is the association between classes that represent an essential relationship between instances of such a class. For example, the relationship between "PhysicalLink" and "Hardware" tells which physical link is connecting which hardware resources. It is important to notice that this kind of relationships do not mandate any particular location of the two connected hardware instances in any MIB. Such containment agnostic relationships can be represented by a typed instance identifier that embodies one direction of such an association (see "Typed instance identifiers"). The YANG module excerpt below shows how the challenges listed above can be addressed by the Complex Types extension (module import prefix "ct:"). The complete YANG module for the physical resource model in Figure 1 can be found in Appendix B: 'YANG Modules for Physical Network Resource Model and Hardware Entities Model'. Note: The YANG extensions proposed in this document have been implemented as the open source tools "Pyang Extension for Complex Types" ([Pyang-ct], ([Pyang]) and "Libsmi Extension for Complex Types" ([Libsmi]). All model examples in the document have been validated with the tools Pyang-ct and Libsmi. module udmcore { namespace "http://example.com/udmcore"; Linowski, et al. Expires April 22, 2011 [Page 10] Internet-Draft YANG Language Abstractions October 2010 prefix "udm"; import ietf-complex-types {prefix "ct"; } // Basic complex types... ct:complex-type PhysicalResource { ct:extends Resource; ct:abstract true; // ... leaf serialNumber {type string;} } ct:complex-type Hardware { ct:extends PhysicalResource; ct:abstract true; // ... leaf-list physicalLink { type instance-identifier {ct:instance-type PhysicalLink;} } ct:instance-list containedHardware { ct:instance-type Hardware; } ct:instance-list physicalConnector { ct:instance-type PhysicalConnector; } } ct:complex-type PhysicalLink { ct:extends PhysicalResource; // ... leaf-list hardware { type instance-identifier {ct:instance-type Hardware;} } } ct:complex-type ManagedHardware { ct:extends Hardware; ct:abstract true; // ... } ct:complex-type PhysicalConnector { ct:extends Hardware; Linowski, et al. Expires April 22, 2011 [Page 11] Internet-Draft YANG Language Abstractions October 2010 leaf location {type string;} // ... leaf-list sourcePhysicalConnector { type instance-identifier {ct:instance-type PhysicalConnector;} } leaf-list targetPhysicalConnector { type instance-identifier {ct:instance-type PhysicalConnector;} } } ct:complex-type Equipment { ct:extends ManagedHardware; // ... ct:instance-list equipment { ct:instance-type Equipment; } } ct:complex-type EquipmentHolder { ct:extends ManagedHardware; leaf vendorName {type string;} // ... ct:instance-list equipment { ct:instance-type Equipment; } ct:instance-list equipmentHolder { ct:instance-type EquipmentHolder; } } // ... } 1.5.2. Modeling Entity MIB Entries as Physical Resources The physical resource module described above can now be used to model physical entities as defined in the Entity MIB [RFC4133]. For each physical entity class listed in the "PhysicalClass" enumeration, a complex type is defined. Each of these complex types extends the most specific complex type already available in the physical resource module. For example, the type "HWModule" extends the complex type "Equipment" as a hardware module. Physical entity properties that should be included in a physical entity complex type are combined in a grouping, which is then used in each complex type definition of an entity. Linowski, et al. Expires April 22, 2011 [Page 12] Internet-Draft YANG Language Abstractions October 2010 This approach has following benefits: o The definition of the complex types for hardware entities becomes compact as many of the features can be reused from the basic complex type definition. o Physical entities are modeled in a consistent manner as predefined concepts are extended. o Entity MIB specific attributes as well as vendor specific attributes can be added without having to define separate extension data nodes. Module umdcore : Module hardware-entities : equipment : Holder : 0..* : +-------+ : | | : +---------------+ +---------+ | : |ManagedHardware|<|-+-|Equipment|<>--+ : +---------------+ | | Holder |0..1 : +-------+ | | |<|---------+--|Chassis| | +---------+ : | +-------+ | <> : | | |0..* equipment : | +---------+ | | Holder : '--|Container| | | : +---------+ | |0..* equipment : | | : | | equipment : | | 0..* : | | +-------+ : | | | | : | +---------+ | : '-|Equipment|<>--+ : +--------+ | |<|---------+--|HWModule| +---------+ : | +--------+ compositeEquipment : | : | +---------+ : |--|Backplane| : +---------+ Linowski, et al. Expires April 22, 2011 [Page 13] Internet-Draft YANG Language Abstractions October 2010 Figure 2: Hardware Entities Model Below is an excerpt of the according YANG module using complex types to model hardware entities. The complete YANG module for the Hardware Entities model in Figure 2 can be found in Appendix B: 'YANG Modules for Physical Network Resource Model and Hardware Entities Model'. Linowski, et al. Expires April 22, 2011 [Page 14] Internet-Draft YANG Language Abstractions October 2010 module hardware-entities { namespace "http://example.com/hardware-entities"; prefix "hwe"; import ietf-yang-types {prefix "yt";} import ietf-complex-types {prefix "ct";} import udmcore {prefix "uc";} grouping PhysicalEntityProperties { // ... leaf mfgDate {type yang:date-and-time; } leaf-list uris {type string; } } // Physical entities representing equipment ct:complex-type HWModule { ct:extends uc:Equipment; description "Complex type representing module entries (entPhysicalClass = module(9)) in entPhysicalTable"; uses PhysicalEntityProperties; } // ... // Physical entities representing equipment holders ct:complex-type Chassis { ct:extends uc:EquipmentHolder; description "Complex type representing chassis entries (entPhysicalClass = chassis(3)) in entPhysicalTable"; uses PhysicalEntityProperties; } // ... } Linowski, et al. Expires April 22, 2011 [Page 15] Internet-Draft YANG Language Abstractions October 2010 2. Complex Types 2.1. Definition YANG type concept is currently restricted to simple types, e.g. restrictions of primitive types, enumerations or union of simple types. Complex types are types with a rich internal structure, which may be composed of substatements defined in Table 1 (e.g. lists, leafs, containers, choices). A new complex type may extend an existing complex type. This allows providing type-safe extensions to existing YANG models as instances of the new type. Complex types have the following characteristics: o Introduction of new types, as a named, formal description of a concrete manageable resource as well as abstract concepts. o Types can be extended, i.e. new types can be defined by specializing existing types adding new features. Instances of such an extended type can be used wherever instances of the base type may appear. o The type information is made part of the NETCONF payload in case a derived type substitutes a base type. This enables easy and efficient consumption of payload elements representing complex type instances. 2.2. complex-type extension statement The extension statement "complex-type" is introduced that accepts an arbitrary number of node tree defining statements among other common YANG statements ("YANG Statements", [RFC6020] Section 7). Linowski, et al. Expires April 22, 2011 [Page 16] Internet-Draft YANG Language Abstractions October 2010 +------------------+-------------+ | substatement | cardinality | +------------------+-------------+ | abstract | 0..1 | | anyxml | 0..n | | choice | 0..n | | container | 0..n | | description | 0..1 | | ct:instance | 0..n | | ct:instance-list | 0..n | | ct:extends | 0..1 | | grouping | 0..n | | if-feature | 0..n | | key | 0..1 | | leaf | 0..n | | leaf-list | 0..n | | list | 0..n | | must | 0..n | | ordered-by | 0..n | | reference | 0..1 | | refine | 0..n | | status | 0..1 | | typedef | 0..n | | uses | 0..n | +------------------+-------------+ Table 1: complex-type's substatements Complex type definitions may appear at every place, where a grouping may be defined. That includes the module, submodule, rpc, input, output, notification, container, and list statements. Complex type names populate a distinct namespace. As with YANG groupings, it is possible to define a complex type and a data node (e.g. leaf, list, instance statements) with the same name in the same scope. All complex type names defined within a parent node or at the top-level of the module or its submodules share the same type identifier namespace. This namespace is scoped to the parent node or module. A complex type MAY have an instance key. An instance key is either defined with the "key" statement as part of the complex type or is inherited from the base complex type. It is not allowed to define an additional key if the base complex type or one of its ancestors already defines a key. Complex-type definitions do not create nodes in the schema tree. Linowski, et al. Expires April 22, 2011 [Page 17] Internet-Draft YANG Language Abstractions October 2010 2.3. instance extension statement The "instance" extension statement is used to instantiate a complex type by creating a subtree in the management information node tree. The instance statement takes one argument that is the identifier of the complex type instance. It is followed by a block of substatements. The type of the instance is specified with the mandatory "ct: instance-type" substatement. The type of an instance MUST be a complex type. Common YANG statements may be used as substatements of the "instance" statement. An instance is by default optional. To make an instance mandatory, "mandatory true" has to be applied as substatement. +------------------+-------------+ | substatement | cardinality | +------------------+-------------+ | description | 0..1 | | config | 0..1 | | ct:instance-type | 1 | | if-feature | 0..n | | mandatory | 0..1 | | must | 0..n | | reference | 0..1 | | status | 0..1 | | when | 0..1 | | anyxml | 0..n | | choice | 0..n | | container | 0..n | | ct:instance | 0..n | | ct:instance-list | 0..n | | leaf | 0..n | | leaf-list | 0..n | | list | 0..n | +------------------+-------------+ Table 2: instance's substatements The "instance" and "instance-list" extension statements (see Section 2.4 "instance-list extension statement") are similar to the existing "leaf" and "leaf-list" statements, with the exception that the content is composed of subordinate elements according to the instantiated complex type. It is also possible to add additional data nodes by using the according leaf, leaf-list, list, and choice statements etc. as sub- statements of the instance declaration. This is an in-place Linowski, et al. Expires April 22, 2011 [Page 18] Internet-Draft YANG Language Abstractions October 2010 augmentation of the used complex type confined to a complex type instantiation (see also Section 2.13 "Using complex types" for details on augmenting complex types). 2.4. instance-list extension statement The "instance-list" extension statement is used to instantiate a complex type by defining a sequence of subtrees in the management information node tree. In addition, the "instance-list" statement takes one argument that is the identifier of the complex type instances. It is followed by a block of substatements. The type of the instance is specified with the mandatory "ct: instance-type" substatement. In addition it can be defined how often an instance may appear in the schema tree by using the min-elements and max-elements substatements. Common YANG statements may be used as substatements of the "instance-list" statement. In analogy to "instance" statement, sub-statement like "list", "choice", leaf" etc. MAY be used to augment the instance list elements at the root level with additional data nodes. +------------------+-------------+ | substatementc | cardinality | +------------------+-------------+ | description | 0..1 | | config | 0..1 | | ct:instance-type | 1 | | if-feature | 0..n | | max-elements | 0..1 | | min-elements | 0..1 | | must | 0..n | | ordered-by | 0..1 | | reference | 0..1 | | status | 0..1 | | when | 0..1 | | anyxml | 0..n | | choice | 0..n | | container | 0..n | | ct:instance | 0..n | | ct:instance-list | 0..n | | leaf | 0..n | | leaf-list | 0..n | | list | 0..n | +------------------+-------------+ Table 3: instance-list's substatements Linowski, et al. Expires April 22, 2011 [Page 19] Internet-Draft YANG Language Abstractions October 2010 In case the instance list represents configuration data, the used complex type of an instance MUST have an instance key. Instances as well as instance lists may appear as arguments of the "deviate" statement. 2.5. extends extension statement A complex type MAY extend exactly one existing base complex type by using the "extends" extension statement. The keyword "extends" MAY occur as substatement of the "complex-type" extension statement. The argument of the "complex-type" extension statement refers to the base complex type via its name. In case a complex type represents configuration data (the default), it MUST have a key, otherwise it MAY have a key. A key is either defined with the key statement as part of the complex type or is inherited from the base complex type. +--------------+-------------+ | substatement | cardinality | +--------------+-------------+ | description | 0..1 | | reference | 0..1 | | status | 0..1 | +--------------+-------------+ Table 4: extends' substatements 2.6. abstract extension statement Complex types may be declared to be abstract by using the "abstract" extension statement. An abstract complex type cannot be instantiated, meaning it cannot appear as most specific type of an instance in NETCONF payload. In case an abstract type extends a base type, the base complex type MUST be also abstract. By default, complex types are not abstract. The abstract complex type serves only as a base type for derived concrete complex types and cannot be used as a type for an instance in NETCONF payload. The "abstract" extension statement takes a single string argument, which is either "true" or "false". In case a "complex-type" statement does not contain an "abstract" statement as substatement, the default is "false". The "abstract" statement does not support any substatements. Linowski, et al. Expires April 22, 2011 [Page 20] Internet-Draft YANG Language Abstractions October 2010 2.7. XML Encoding Rules An "instance" node is encoded as an XML element, where an "instance- list" node is encoded as a series of XML elements. The XML element name is the "instance" respectively "instance-list" identifier, and its XML namespace is the module's XML namespace. Instance child nodes are encoded as subelements of the instance XML element. Subelements representing child nodes defined in the same complex type may appear in any order. However child nodes of an extending complex type follow the child nodes of the extended complex type. As such, the XML encoding of lists is similar to the encoding of containers and lists in YANG. Instance key nodes are encoded as subelements of the instance XML element. Instance key nodes must appear in the same order as they are defined within the "key" statement of the according complex type definition and precede all other nodes defined in the same complex type. I.e. if key nodes are defined in an extending complex type, XML elements representing key data precede all other XML elements representing child nodes. On the other hand XML elements representing key data follow the XML elements representing data nodes of the base type. The type of actual complex type instance is encoded in a type element, which is put in front of all instance child elements, including key nodes, as described in Section 2.8 ("Type Encoding Rules"). The proposed XML encoding rules conform to the YANG XML encoding rules in [RFC6020]. Compared to YANG, enabling key definitions in derived hierarchies is a new feature introduced with the complex types extension. As a new language feature complex types introduce also a new payload entry for the instance type identifier. Based on our implementation experience, the proposed XML encoding rules support consistent mapping of YANG models with complex types to XML Schema using XML complex types. 2.8. Type Encoding Rules In order to encode the type of an instance in NETCONF payload, XML elements named "type" belonging to the XML namespace "urn:ietf:params:xml:ns:yang:ietf-complex-type-instance" are added to the serialized form of instance and instance-list nodes in the payload. The suggested namespace prefix is "cti". The "cti:type" XML elements are inserted before the serialized form of all members that have been declared in the according complex type definition. Linowski, et al. Expires April 22, 2011 [Page 21] Internet-Draft YANG Language Abstractions October 2010 The "cti:type" element is inserted for each type in the extension chain to the actual type of the instance (most specific last). Each type name includes its corresponding namespace. The type of a complex type instance MUST be encoded in the reply to NETCONF and operations, and in the payload of NETCONF operation if the operation is "create" or "replace". The type of the instance MUST also be specified in case is used to export a configuration to a resource addressed with an URI. The type of the instance has to be specified in user defined RPC's. The type of the instance MAY be specified in case the operation is "merge" (either because this is explicitly specified or no operation attribute is provided). In case the node already exists in the target configuration and the type attribute (type of a complex type instance) is specified but differs from the data in the target, an element is returned with an value of "wrong-complex-type". In case no such element is present in the target configuration but the type attribute is missing in the configuration data, an element is returned with an value of "missing-attribute". The type MUST NOT be specified in case the operation is "delete". 2.9. Extension and Feature Definition Module The module below contains all YANG extension definitions for complex types and typed instance identifiers. In addition a "complex-type" feature is defined, which may be used to provide conditional or alternative modeling for depending on the support status of complex types in a NETCONF server. A NETCONF server that supports the complex types modeling features and the XML encoding for complex types as defined in this document MUST advertise this as a feature. This is done by including the feature name "complex-types" into the feature parameter list as part of the NETCONF message as described in Section 5.6.4 in [RFC6020]. file "ietf-complex-types@2010-10-05.yang" module ietf-complex-types { namespace "urn:ietf:params:xml:ns:yang:ietf-complex-types"; prefix "ct"; Linowski, et al. Expires April 22, 2011 [Page 22] Internet-Draft YANG Language Abstractions October 2010 organization "NETMOD WG"; contact "Editor: Bernd Linowski Editor: Mehmet Ersue Editor: Siarhei Kuryla "; description "YANG extensions for complex types and typed instance identifiers. Copyright (c) 2010 IETF Trust and the persons identified as the document authors. All rights reserved. Redistribution and use in source and binary forms, with or without modification, is permitted pursuant to, and subject to the license terms contained in, the Simplified BSD License set forth in Section 4.c of the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info). This version of this YANG module is part of RFC XXXX; see the RFC itself for full legal notices."; // RFC Ed.: Please replace XXXX with actual RFC number and // remove this note revision 2010-10-19 { description "Initial revision."; } // RFC Ed.: Please replace the date of the revision statement // with RFC publication date and remove this note extension complex-type { description "Defines a complex-type."; reference "section 2.2., complex-type extension statement"; argument type-identifier { yin-element true; } } Linowski, et al. Expires April 22, 2011 [Page 23] Internet-Draft YANG Language Abstractions October 2010 extension extends { description "Defines the base type of a complex-type."; reference "section 2.5., extends extension statement"; argument base-type-identifier { yin-element true; } } extension abstract { description "Makes the complex-type abstract."; reference "section 2.6., abstract extension statement"; argument status; } extension instance { description "Declares an instance of the given complex type."; reference "section 2.3., instance extension statement"; argument ct-instance-identifier { yin-element true; } } extension instance-list { description "Declares a list of instances of the given complex type"; reference "section 2.4., instance-list extension statement"; argument ct-instance-identifier { yin-element true; } } extension instance-type { description "Tells to which type instance the instance identifier refers to."; reference "section 3.2., instance-type extension statement"; argument target-type-identifier { yin-element true; } } feature complex-types { description "This feature indicates that the server supports complex types and instance identifiers."; } Linowski, et al. Expires April 22, 2011 [Page 24] Internet-Draft YANG Language Abstractions October 2010 } 2.10. Example Model for Complex Types The example model below shows how complex types can be used to represent physical equipment in a vendor independent, abstract way. It reuses the complex types defined in the physical resource model in Section 1.5.1 Linowski, et al. Expires April 22, 2011 [Page 25] Internet-Draft YANG Language Abstractions October 2010 module hw { namespace "http://example.com/hw"; prefix "hw"; import ietf-complex-types {prefix "ct"; } import udmcore {prefix "uc"; } // Holder types ct:complex-type Slot { ct:extends uc:EquipmentHolder; leaf slotNumber { type uint16; config false; } // ... } ct:complex-type Chassis { ct:extends uc:EquipmentHolder; leaf numberOfChassisSlots { type uint32; config false; } // .. } // Equipment types ct:complex-type Card { ct:extends uc:Equipment; leaf position { type uint32; mandatory true; } leaf slotsRequired {type unit32; } } // Root Element ct:instance hardware { type uc:ManagedHardware; } } // hw module 2.11. NETCONF Payload Example Following example shows the payload of a reply to a NETCONF command. The actual type of managed hardware instances is indicated with the "cti:type" elements as required by the type encoding rules. The containment hierarchy in the NETCONF XML payload reflects the containment hierarchy of hardware instances. This makes filtering Linowski, et al. Expires April 22, 2011 [Page 26] Internet-Draft YANG Language Abstractions October 2010 based on the containment hierarchy possible without having to deal with values of key-ref leafs that represent the tree structure in a flattened hierarchy. Linowski, et al. Expires April 22, 2011 [Page 27] Internet-Draft YANG Language Abstractions October 2010 uc:BasicObject /R-T31/CH-2 6278279001 uc:Resource uc:PhysicalResource Rack R322-1 R-US-3276279a uc:Hardware uc:ManagedHardware hw:EquipmentHolder uc:BasicObject /R-T31/CH-2/SL-1 548872003 uc:Resource uc:PhysicalResource CU-Slot T-K4733890x45 uc:Hardware uc:ManagedHardware uc:EquipmentHolder uc:BasicObject /R-T31/CH-2/SL-1/C-3 89772001 uc:Resource uc:PhysicalResource ATM-45252 A-778911-b uc:Hardware uc:ManagedHardware uc:Equipment true A2 1 hw:Card 1 hw:Slot 1 hw:Chassis 6 // ... Linowski, et al. Expires April 22, 2011 [Page 28] Internet-Draft YANG Language Abstractions October 2010 2.12. Update Rules for Modules Using Complex Types In addition to the module update rules specified in Section 10 in [RFC6020], modules that define complex-types, instances of complex types and typed instance identifiers must obey following rules: o New complex types MAY be added. o A new complex type MAY extend an existing complex type. o New data definition statements MAY be added to a complex type only if: * they are not mandatory or * they are not conditionally dependent on a new feature (i.e., have an "if-feature" statement, which refers to a new feature). o The type referred to by the instance-type statement may be changed to a type that derives from the original type only if the original type does not represent configuration data. 2.13. Using Complex Types All data nodes defined inside a complex type reside in the complex type namespace, which is their parent node namespace. 2.13.1. Overriding Complex Type Data Nodes It is not allowed to override a data node inherited from a base type. I.e. it is an error if a type "base" with a leaf named "foo" is extended by another complex type ("derived") with a leaf named "foo" in the same module. In case they are derived in different modules, there are two distinct "foo" nodes which are mapped to the XML namespaces of the module, where the complex types are specified. A complex type that extends a basic complex type may use the "refine" statement in order to improve an inherited data node. The target node identifier must be qualified by the module prefix to indicate clearly, which inherited node is refined. The following refinements can be done: o A leaf or choice node may have a default value, or a new default value if it already had one o Any node may have a different "description" or "reference" string. Linowski, et al. Expires April 22, 2011 [Page 29] Internet-Draft YANG Language Abstractions October 2010 o A leaf, anyxml, or choice node may have a "mandatory true" statement. However, it is not allowed to change from "mandatory true" to "mandatory false". o A leaf, leaf-list, list, container, or anyxml node may have additional "must" expressions. o A list, leaf-list, instance or instance-list node may have a "min- elements" statement, if the base type does not have one or one with a value that is greater than the minimum value of the base type. o A list, leaf-list, instance or instance-list node may have a "max- elements" statement, if the base type does not have one or one with a value that is smaller than the maximum value of the base type. It is not allowed to refine complex-type nodes inside instance or instance-list statements. 2.13.2. Augmenting Complex Types Augmenting complex types is only allowed if a complex type is instantiated in an "instance" or "instance-list" statement. This confines the effect of the augmentation to the location in the schema tree, where the augmentation is done. The argument of the "augment" statement MUST be in the descendant form (as defined by the rule "descendant-schema-nodeid" in Section 12 in [RFC6020]). ct:complex-type Chassis { ct:extends EquipmentHolder; container chassisInfo { config false; leaf numberOfSlots { type uint16; } leaf occupiedSlots { type uint16; } leaf height {type unit16;} leaf width {type unit16;} } } ct:instance-list chassis { type Chassis; augment "chassisInfo" { leaf modelId { type string; } } } Linowski, et al. Expires April 22, 2011 [Page 30] Internet-Draft YANG Language Abstractions October 2010 When augmenting a complex type, only the "container", "leaf", "list", "leaf-list", "choice", "instance", "instance-list" and "if-feature" statements may be used within the "augment" statement. The nodes added by the augmentation MUST NOT be mandatory nodes. One or many augment statements may not cause the creation of multiple nodes with the same name from the same namespace in the target node. To achieve less complex modeling this document proposes the augmentation of complex type instances without recursion. 2.13.3. Controlling the Use of Complex Types A server might not want to support all complex types defined in a supported module. This issue can be addressed with YANG features as follows: o Features are defined that are used inside complex type definitions (by using "if-feature" as substatement) to make them optional. In this case such complex types may only be instantiated if the feature is supported (advertized as capability in the NETCONF message). o The "deviation" statement may be applied to node trees, which are created by "instance" and "instance-list" statements. In this case, only the substatement "deviate not-supported" is allowed. o It is not allowed to apply the deviation statement to node tree elements that may occur because of the recursive use of a complex type. Other forms of deviations ("deviate add", "deviate replace", "deviate delete") are NOT supported inside node trees spanned by "instance" or "instance-list". As complex type definitions do not contribute by itself to the data node tree, data node declarations inside complex types cannot be target of deviations. In the example below, client applications are informed that the leaf "occupiedSlots" is not supported in the top-level chassis. However, if a chassis contains another chassis, the contained chassis may support the leaf informing about the number of occupied slots. deviation "/chassis/chassisSpec/occupiedSlots" { deviate not-supported; } Linowski, et al. Expires April 22, 2011 [Page 31] Internet-Draft YANG Language Abstractions October 2010 3. Typed Instance Identifier 3.1. Definition Typed instance identifier relationships are an addition to the relationship types already defined in YANG, where the leafref relationship is location dependent, and the instance-identifier does not specify to which type of instances the identifier points to. A typed instance identifier represents a reference to an instance of a complex type without being restricted to a particular location in the containment tree. This is done by using the extension statement "instance-type" as a substatement of the existing "type instance identifier" statement. Typed instance identifiers allow referring to instances of complex types that may be located anywhere in the schema tree. The "type" statement plays the role of a restriction that must be fulfilled by the target node, which is referred to with the instance identifier. The target node MUST be of a particular complex type, either the type itself or any type that extends this complex type. 3.2. instance-type extension statement The "instance-type" extension statement specifies the complex type of the instance referred by the instance-identifier. The referred instance may also instantiate any complex type that extends the specified complex type. The instance complex type is identified by the single name argument. The referred complex type MUST have a key. This extension statement MUST be used as a substatement of the "type instance-identifier" statement. The "instance-type" extension statement does not support any substatements. 3.3. Typed Instance Identifier Example In the example below, a physical link connects an arbitrary number of physical ports. Here typed instance identifiers are used to denote, which "PhysicalPort" instances (anywhere in the data tree) are connected by a "PhysicalLink". Linowski, et al. Expires April 22, 2011 [Page 32] Internet-Draft YANG Language Abstractions October 2010 // Extended version of type Card ct:complex-type Card { ct:extends Equipment; leaf usedSlot { type uint16; mandatory true; } ct:instance-list port { type PhysicalPort; } } ct:complex-type PhysicalPort { ct:extends ManagedHardware; leaf portNumber { type int32; mandatory true; } } ct:complex-type PhysicalLink { ct:extends ManagedHardware; leaf media { type string; } leaf-list connectedPort { type instance-identifier { ct:instance-type PhysicalPort; } min-elements 2; } } Below is the XML encoding of an element named "link" of type "PhysicalLink": FTCL-771 Fiber /hw:hardware[objectId='R-11'] /hw:equipment[objectId='AT22']/hw:port[objectId='P12'] /hw:hardware[objectId='R-42] /hw:equipment[objectId='AT30']/hw:port[objectId='P3'] F-7786828 FibCon 7 4. IANA Considerations This document registers two URIs in the IETF XML registry. Following the format in [RFC3688], the following registrations are requested: Linowski, et al. Expires April 22, 2011 [Page 33] Internet-Draft YANG Language Abstractions October 2010 URI: urn:ietf:params:xml:ns:yang:ietf-complex-types URI: urn:ietf:params:xml:ns:yang:ietf-complex-type-instance Registrant Contact: The NETMOD WG of the IETF. XML: N/A, the requested URIs are XML namespaces. This document registers one module name in the 'YANG Module Names' registry, defined in [RFC6020]. name: ietf-complex-types namespace: urn:ietf:params:xml:ns:yang:ietf-complex-types prefix: ct RFC: XXXX RFC Ed.: Please replace XXXX with actual RFC number and remove this note. 5. Security Considerations The YANG module "complex-types" in this memo defines YANG extensions for Complex-types and Typed Instance Identifiers as new language statements. Complex-types and Typed Instance Identifiers themselves do not have any security impact on the Internet. The security considerations described throughout [RFC6020] apply here as well. 6. Acknowledgements The authors would like to thank to Martin Bjorklund, Balazs Lengyel, Gerhard Muenz, Dan Romascanu, Juergen Schoenwaelder and Martin Storch for their valuable review and comments on different versions of the document. 7. References 7.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", March 1997. Linowski, et al. Expires April 22, 2011 [Page 34] Internet-Draft YANG Language Abstractions October 2010 [RFC3688] Mealling, M., "The IETF XML Registry", January 2004. [RFC5226] Narten, T., "Guidelines for Writing an IANA Considerations Section in RFCs", May 2008. [RFC6020] Bjorklund, M., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", October 2010. 7.2. Informative References [IPFIXCONF] Muenz, G., "Configuration Data Model for IPFIX and PSAMP", draft-ietf-ipfix-configuration-model-07 (work in progress), July 2010. [Libsmi] Kuryla, S., "Libsmi Extension for Complex Types", April 2010, . [Pyang] Bjorklund, M., "An extensible YANG validator and converter", October 2010, . [Pyang-ct] Kuryla, S., "Pyang Extension for Complex Types", April 2010, . [RFC4133] Bierman, A. and K. McCloghrie, "Entity MIB (Version 3)", August 2005. [SID V8] Tele Management Forum, "GB922-Information Framework (SID) Solution Suite, Release 8.0", July 2008, < http:/ /www.tmforum.org/DocumentsInformation/ GB922InformationFramework/35499/article.html>. [UDM] NSN, "Unified Data Model SID Compliance Statement", May 2010, . Appendix A. Change Log A.1. 03-04 o Changed the complex type XML encoding rules so that XML elements reprensenting data nodes defined in the same complex type may appear in any order. o Used the "ct:" prefix in substatement tables when referring to complex type extension statements. Linowski, et al. Expires April 22, 2011 [Page 35] Internet-Draft YANG Language Abstractions October 2010 o Modeled the IPFIX/PSMAP example based on v-07 of the IPFIX configuration draft. Changed motivation text accordingly. o Minor updates and clarifications in the text. A.2. 02-03 o Added an example based on the physical resource modeling concepts of SID. A simplified class diagram and an excerpt of an according YANG module were added in the introduction section. o Changed the example YANG module in the NETCONF payload section to be based on the physical resource types defined in the added physical resource model. o A second example shows how Entity MIB entries can be modeled as physical resources. The example includes a class diagram and an according YANG module excerpt. o The complete YANG modules for both examples were added into the appendix. o Changed the complex type encoding rules. o Updated the NETCONF payload example the changed type encoding rules and the changed example module. o Changed the augmentation rules for complex types. Instead of using "." as argument in the augment statement, instance and instance-list statement may now contain additional data node statements. The substatement tables for the instance and instance-list statements were updated accordingly. o Minor updates in the text and examples. A.3. 01-02 o It is no longer allowed to use the "config" statement inside a complex type definition. o Complex type can now be defined where a grouping can be defined. Complex types have their own namespace. o Explicitly specified which kind of refinements can be applied to elements of the base type in the definition of an extending complex type. Linowski, et al. Expires April 22, 2011 [Page 36] Internet-Draft YANG Language Abstractions October 2010 o Confined the use of deviations for complex types to complex type instantiations. o Defined augmentation of complex types allowing augmentation only during instantiation via an "instance" or "instance-list" statement. o Removed leftovers from substatement tables. o Updates and bug-fixes in the examples. A.4. 00-01 o Transformed proposed new YANG statements to YANG extension statements (complex-type, element, extends, abstract). o Renamed statement "element" to the extension statement "instance" in order to avoid confusion with XML payload elements. o Introduced extension statement "instance-type" as allowing the use of the existing "type" statement as substatement in the existing "instance-identifier" statement cannot be done with extensions. o Added the complex type extension statement module. o Updated examples to reflect the changes mentioned above. o Added update rules for complex types. o Updated IANA Considerations section. o Added this change log. Appendix B. YANG Modules for Physical Network Resource Model and Hardware Entities Model YANG module for the 'Physical Network Resource Model': module udmcore { namespace "http://example.com/udmcore"; prefix "udm"; import ietf-yang-types {prefix "yang";} import ietf-complex-types {prefix "ct";} Linowski, et al. Expires April 22, 2011 [Page 37] Internet-Draft YANG Language Abstractions October 2010 ct:complex-type BasicObject { ct:abstract true; key "distinguishedName"; leaf globalId {type int64;} leaf distinguishedName {type string; mandatory true;} } ct:complex-type ManagedObject { ct:extends BasicObject; ct:abstract true; leaf instance {type string;} leaf objectState {type int32;} leaf release {type string;} } ct:complex-type Resource { ct:extends ManagedObject; ct:abstract true; leaf usageState {type int16;} leaf managementMethodSupported {type string;} leaf managementMethodCurrent {type string;} leaf managementInfo {type string;} leaf managementDomain {type string;} leaf version {type string;} leaf entityIdentification {type string;} leaf desription {type string;} leaf rootEntityType {type string;} } ct:complex-type LogicalResource { ct:extends Resource; ct:abstract true; leaf lrStatus {type int32;} leaf serviceState {type int32;} leaf isOperational {type boolean;} } ct:complex-type PhysicalResource { ct:extends Resource; ct:abstract true; leaf manufactureDate {type string;} leaf otherIdentifier {type string;} leaf powerState {type int32;} leaf serialNumber {type string;} leaf versionNumber {type string;} Linowski, et al. Expires April 22, 2011 [Page 38] Internet-Draft YANG Language Abstractions October 2010 } ct:complex-type Hardware { ct:extends PhysicalResource; ct:abstract true; leaf width {type string;} leaf height {type string;} leaf depth {type string;} leaf measurementUnits {type int32;} leaf weight {type string;} leaf weightUnits {type int32;} leaf-list physicalLink { type instance-identifier { ct:instance-type PhysicalLink; } } ct:instance-list containedHardware { ct:instance-type Hardware; } ct:instance-list physicalConnector { ct:instance-type PhysicalConnector; } } ct:complex-type PhysicalLink { ct:extends PhysicalResource; leaf isWiereless {type boolean;} leaf currentLength {type string;} leaf maximumLength {type string;} leaf mediaType {type int32;} leaf-list hardware { type instance-identifier { ct:instance-type Hardware; } } } ct:complex-type ManagedHardware { ct:extends Hardware; leaf additionalinfo {type string;} leaf physicalAlarmReportingEnabled {type boolean;} leaf pyhsicalAlarmStatus {type int32;} leaf coolingRequirements {type string;} leaf hardwarePurpose {type string;} leaf isPhysicalContainer {type boolean;} Linowski, et al. Expires April 22, 2011 [Page 39] Internet-Draft YANG Language Abstractions October 2010 } ct:complex-type AuxiliaryComponent { ct:extends ManagedHardware; ct:abstract true; } ct:complex-type PhysicalPort { ct:extends ManagedHardware; leaf portNumber {type int32;} leaf duplexMode {type int32;} leaf ifType {type int32;} leaf vendorPortName {type string;} } ct:complex-type PhysicalConnector { ct:extends Hardware; leaf location {type string;} leaf cableType {type int32;} leaf gender {type int32;} leaf inUse {type boolean;} leaf pinDescription {type string;} leaf typeOfConnector {type int32;} leaf-list sourcePhysicalConnector { type instance-identifier { ct:instance-type PhysicalConnector; } } leaf-list targetPhysicalConnector { type instance-identifier { ct:instance-type PhysicalConnector; } } } ct:complex-type Equipment { ct:extends ManagedHardware; leaf installStatus {type int32;} leaf expectedEquipmentType {type string;} leaf installedEquipmentType {type string;} leaf installedVersion {type string;} leaf redundancy {type int32;} leaf vendorName {type string;} leaf dateOfLastService {type yang:date-and-time;} Linowski, et al. Expires April 22, 2011 [Page 40] Internet-Draft YANG Language Abstractions October 2010 leaf interchangeability {type string;} leaf identificationCode {type string;} ct:instance-list equipment { ct:instance-type Equipment; } } ct:complex-type EquipmentHolder { ct:extends ManagedHardware; leaf vendorName {type string;} leaf locationName {type string;} leaf dateOfLastService {type yang:date-and-time;} leaf partNumber {type string;} leaf availabilityStatus {type int16;} leaf nameFromPlanningSystem {type string;} leaf modelNumber {type string;} leaf acceptableEquipmentList {type string;} leaf isSolitaryHolder {type boolean;} leaf holderStatus {type int16;} leaf interchangeability {type string;} leaf equipmentHolderSpecificType {type string; } leaf position {type string;} leaf atomicCompositeType {type int16;} leaf uniquePhysical {type boolean;} leaf physicalDescription {type string;} leaf serviceApproach {type string;} leaf mountingOptions {type int32;} leaf cableManagementStrategy {type string;} leaf isSecureHolder {type boolean;} ct:instance-list equipment { ct:instance-type Equipment; } ct:instance-list equipmentHolder { ct:instance-type EquipmentHolder; } } // ... other resource complex types ... } YANG module for the 'Hardware Entities Model': Linowski, et al. Expires April 22, 2011 [Page 41] Internet-Draft YANG Language Abstractions October 2010 module hardware-entities { namespace "http://example.com/:hardware-entities"; prefix "hwe"; import ietf-yang-types {prefix "yang";} import ietf-complex-types {prefix "ct";} import udmcore {prefix "uc";} grouping PhysicalEntityProperties { leaf hardwareRev {type string; } leaf firmwareRev {type string; } leaf softwareRev {type string; } leaf serialNum {type string; } leaf mfgName {type string; } leaf modelName {type string; } leaf alias {type string; } leaf ssetID{type string; } leaf isFRU {type boolean; } leaf mfgDate {type yang:date-and-time; } leaf-list uris {type string; } } // Physical entities representing equipment ct:complex-type Module { ct:extends uc:Equipment; description "Complex type representing module entries (entPhysicalClass = module(9)) in entPhysicalTable"; uses PhysicalEntityProperties; } ct:complex-type Backplane { ct:extends uc:Equipment; description "Complex type representing backplane entries (entPhysicalClass = backplane(4)) in entPhysicalTable"; uses PhysicalEntityProperties; } // Physical entities representing auxiliray hardware components ct:complex-type PowerSupply { ct:extends uc:AuxiliaryComponent; description "Complex type representing power supply entries Linowski, et al. Expires April 22, 2011 [Page 42] Internet-Draft YANG Language Abstractions October 2010 (entPhysicalClass = powerSupply(6)) in entPhysicalTable"; uses PhysicalEntityProperties; } ct:complex-type Fan { ct:extends uc:AuxiliaryComponent; description "Complex type representing fan entries (entPhysicalClass = fan(7)) in entPhysicalTable"; uses PhysicalEntityProperties; } ct:complex-type Sensor { ct:extends uc:AuxiliaryComponent; description "Complex type representing sensor entries (entPhysicalClass = sensor(8)) in entPhysicalTable"; uses PhysicalEntityProperties; } // Physical entities representing equipment holders ct:complex-type Chassis { ct:extends uc:EquipmentHolder; description "Complex type representing chassis entries (entPhysicalClass = chassis(3)) in entPhysicalTable"; uses PhysicalEntityProperties; } ct:complex-type Container { ct:extends uc:EquipmentHolder; description "Complex type representing container entries (entPhysicalClass = container(5)) in entPhysicalTable"; uses PhysicalEntityProperties; } ct:complex-type Stack { ct:extends uc:EquipmentHolder; description "Complex type representing stack entries (entPhysicalClass = stack(11)) in entPhysicalTable"; uses PhysicalEntityProperties; } // Other kinds of physical entities ct:complex-type Port { ct:extends uc:PhysicalPort; description "Complex type representing port entries Linowski, et al. Expires April 22, 2011 [Page 43] Internet-Draft YANG Language Abstractions October 2010 (entPhysicalClass = port(10)) in entPhysicalTable"; uses PhysicalEntityProperties; } ct:complex-type CPU { ct:extends uc:Hardware; description "Complex type representing cpu entries (entPhysicalClass = cpu(12)) in entPhysicalTable"; uses PhysicalEntityProperties; } } Appendix C. Example YANG Module for the IPFIX/PSAMP Model C.1. Modeling Improvements for the IPFIX/PSAMP Model with Complex types and Typed instance identifiers The module below is a variation of the IPFIX/PSAMP configuration model, which uses complex types and typed instance identifiers to model the concept outlined in [IPFIXCONF]. When looking at the YANG module with complex types and typed instance identifiers, various technical improvements on modeling level become apparent. o There is almost a one-to-one mapping between the domain concepts introduced in IPFIX and the complex types in the YANG module o All associations between the concepts (which are not containment) are represented with typed identifiers. That avoids having to refer to a particular location in the tree, which is not mandated by the original model. o It is superfluous to represent concept refinement (class inheritance in the original model) with containment in form of quite big choice-statements with complex branches. Instead, concept refinement is realized by complex types extending a base complex type. o It is unnecessary to introduce metadata identities and leafs (e.g. "identity cacheMode" and "leaf cacheMode" in "grouping cacheParameters") that just serve the purpose of indicating which concrete sub-type of a generic type (modeled as grouping, which contains the union of all features of all subtypes) is actually represented in the MIB. Linowski, et al. Expires April 22, 2011 [Page 44] Internet-Draft YANG Language Abstractions October 2010 o Ruling out illegal use of sub-type specific properties (e.g. "leaf maxFlows") by using "when" statements that refer to a sub-type discriminator is not necessary (e.g. when "../cacheMode != 'immediate'"). o It is not needed to define properties like the configuration status wherever a so called "parameter grouping" is used. Instead those definitions can be put inside the complex-type definition itself. o It can be avoided to separating the declaration of the key from the related data nodes definitions in a grouping (see use of "grouping selectorParameters"). o Complex types may be declared as optional features. If the type is indicated with an identity (e.g. "identity immediate"), this is not possible, since "if-feature" is not allowed as a substatement of "identity". C.2. IPFIX/PSAMP Model with Complex Types and Typed Instance Identifiers module ct-ipfix-psamp-example { namespace "http://example.com/ns/ct-ipfix-psamp-example"; prefix ipfix; import ietf-yang-types { prefix yang; } import ietf-inet-types { prefix inet; } import ietf-complex-types {prefix "ct"; } description "Example IPFIX/PSAMP Configuration Data Model with complex types and typed instance identifiers"; revision 2010-10-19 { description "Version of draft-ietf-ipfix-configuration-model-07 modeled with complex types and typed instance identifiers."; } /***************************************************************** * Features *****************************************************************/ feature exporter { description "If supported, the Monitoring Device can be used as an Exporter. Exporting Processes can be configured."; } Linowski, et al. Expires April 22, 2011 [Page 45] Internet-Draft YANG Language Abstractions October 2010 feature collector { description "If supported, the Monitoring Device can be used as a Collector. Collecting Processes can be configured."; } feature meter { description "If supported, Observation Points, Selection Processes, and Caches can be configured."; } feature psampSampCountBased { description "If supported, the Monitoring Device supports count-based Sampling..."; } feature psampSampTimeBased { description "If supported, the Monitoring Device supports time-based Sampling..."; } feature psampSampRandOutOfN { description "If supported, the Monitoring Device supports random n-out-of-N Sampling..."; } feature psampSampUniProb { description "If supported, the Monitoring Device supports uniform probabilistic Sampling..."; } feature psampFilterMatch { description "If supported, the Monitoring Device supports property match Filtering..."; } feature psampFilterHash { description "If supported, the Monitoring Device supports hash-based Filtering..."; } feature cacheModeImmediate { description "If supported, the Monitoring Device supports Cache Mode 'immediate'."; } feature cacheModeTimeout { description "If supported, the Monitoring Device supports Cache Mode 'timeout'."; Linowski, et al. Expires April 22, 2011 [Page 46] Internet-Draft YANG Language Abstractions October 2010 } feature cacheModeNatural { description "If supported, the Monitoring Device supports Cache Mode 'natural'."; } feature cacheModePermanent { description "If supported, the Monitoring Device supports Cache Mode 'permanent'."; } feature udpTransport { description "If supported, the Monitoring Device supports UDP as transport protocol."; } feature tcpTransport { description "If supported, the Monitoring Device supports TCP as transport protocol."; } feature fileReader { description "If supported, the Monitoring Device supports the configuration of Collecting Processes as File Readers."; } feature fileWriter { description "If supported, the Monitoring Device supports the configuration of Exporting Processes as File Writers."; } /***************************************************************** * Identities *****************************************************************/ /*** Hash function identities ***/ identity hashFunction { description "Base identity for all hash functions..."; } identity BOB { base "hashFunction"; description "BOB hash function"; reference "RFC5475, Section 6.2.4.1."; } identity IPSX { base "hashFunction"; description "IPSX hash function"; Linowski, et al. Expires April 22, 2011 [Page 47] Internet-Draft YANG Language Abstractions October 2010 reference "RFC5475, Section 6.2.4.1."; } identity CRC { base "hashFunction"; description "CRC hash function"; reference "RFC5475, Section 6.2.4.1."; } /*** Export mode identities ***/ identity exportMode { description "Base identity for different usages of export destinations configured for an Exporting Process..."; } identity parallel { base "exportMode"; description "Parallel export of Data Records to all destinations configured for the Exporting Process."; } identity loadBalancing { base "exportMode"; description "Load-balancing between the different destinations..."; } identity fallback { base "exportMode"; description "Export to the primary destination..."; } /*** Options type identities ***/ identity optionsType { description "Base identity for report types exported with options..."; } identity meteringStatistics { base "optionsType"; description "Metering Process Statistics."; reference "RFC 5101, Section 4.1."; } identity meteringReliability { base "optionsType"; description "Metering Process Reliability Statistics."; reference "RFC 5101, Section 4.2."; } identity exportingReliability { base "optionsType"; description "Exporting Process Reliability Statistics."; reference "RFC 5101, Section 4.3."; Linowski, et al. Expires April 22, 2011 [Page 48] Internet-Draft YANG Language Abstractions October 2010 } identity flowKeys { base "optionsType"; description "Flow Keys."; reference "RFC 5101, Section 4.4."; } identity selectionSequence { base "optionsType"; description "Selection Sequence and Selector Reports."; reference "RFC5476, Sections 6.5.1 and 6.5.2."; } identity selectionStatistics { base "optionsType"; description "Selection Sequence Statistics Report."; reference "RFC5476, Sections 6.5.3."; } identity accuracy { base "optionsType"; description "Accuracy Report."; reference "RFC5476, Section 6.5.4."; } identity reducingRedundancy { base "optionsType"; description "Enables the utilization of Options Templates to reduce redundancy in the exported Data Records."; reference "RFC5473."; } identity extendedTypeInformation { base "optionsType"; description "Export of extended type information for enterprise-specific Information Elements used in the exported Templates."; reference "RFC5610."; } /***************************************************************** * Type definitions *****************************************************************/ typedef nameType { type string { length "1..max"; pattern "\S(.*\S)?"; } description "Type for 'name' leafs..."; } typedef direction { Linowski, et al. Expires April 22, 2011 [Page 49] Internet-Draft YANG Language Abstractions October 2010 type enumeration { enum ingress { description "This value is used for monitoring incoming packets."; } enum egress { description "This value is used for monitoring outgoing packets."; } enum both { description "This value is used for monitoring incoming and outgoing packets."; } } description "Direction of packets going through an interface or linecard."; } typedef transportSessionStatus { type enumeration { enum inactive { description "This value MUST be used for..."; } enum active { description "This value MUST be used for..."; } enum unknown { description "This value MUST be used if the status..."; } } description "Status of a Transport Session."; reference "RFC5815, Section 8 (ipfixTransportSessionStatus)."; } /***************************************************************** * Complex types *****************************************************************/ ct:complex-type ObservationPoint { description "Observation Point"; key name; leaf name { type nameType; description "Key of an observation point."; } leaf observationPointId { type uint32; config false; Linowski, et al. Expires April 22, 2011 [Page 50] Internet-Draft YANG Language Abstractions October 2010 description "Observation Point ID..."; reference "RFC5102, Section 5.1.10."; } leaf observationDomainId { type uint32; mandatory true; description "The Observation Domain ID associates..."; reference "RFC5101."; } choice OPLocation { mandatory true; description "Location of the Observation Point."; leaf ifIndex { type uint32; description "Index of an interface..."; reference "RFC 1229."; } leaf ifName { type string; description "Name of an interface..."; reference "RFC 1229."; } leaf entPhysicalIndex { type uint32; description "Index of a linecard..."; reference "RFC 4133."; } leaf entPhysicalName { type string; description "Name of a linecard..."; reference "RFC 4133."; } } leaf direction { type direction; default both; description "Direction of packets...."; } leaf-list selectionProcess { type instance-identifier { ct:instance-type SelectionProcess; } description "Selection Processes in this list process packets in parallel."; } } ct:complex-type Selector { ct:abstract true; description "Abstract selector"; Linowski, et al. Expires April 22, 2011 [Page 51] Internet-Draft YANG Language Abstractions October 2010 key name; leaf name { type nameType; description "Key of a selector"; } leaf packetsObserved { type yang:counter64; config false; description "The number of packets observed ..."; reference "RFC5815, Section 8 (ipfixSelectorStatsPacketsObserved)."; } leaf packetsDropped { type yang:counter64; config false; description "The total number of packets discarded ..."; reference "RFC5815, Section 8 (ipfixSelectorStatsPacketsDropped)."; } leaf selectorDiscontinuityTime { type yang:date-and-time; config false; description "Timestamp of the most recent occasion at which one or more of the Selector counters suffered a discontinuity..."; reference "RFC5815, Section 8 (ipfixSelectionProcessStatsDiscontinuityTime)."; } } ct:complex-type SelectAllSelector { ct:extends Selector; description "Method which selects all packets."; } ct:complex-type SampCountBasedSelector { if-feature psampSampCountBased; ct:extends Selector; description "Selector applying systematic count-based packet sampling to the packet stream."; reference "RFC5475, Section 5.1; RFC5476, Section 6.5.2.1."; leaf packetInterval { type uint32; units packets; mandatory true; description "The number of packets that are consecutively sampled between gaps of length packetSpace. Linowski, et al. Expires April 22, 2011 [Page 52] Internet-Draft YANG Language Abstractions October 2010 This parameter corresponds to the Information Element samplingPacketInterval."; reference "RFC5477, Section 8.2.2."; } leaf packetSpace { type uint32; units packets; mandatory true; description "The number of unsampled packets between two sampling intervals. This parameter corresponds to the Information Element samplingPacketSpace."; reference "RFC5477, Section 8.2.3."; } } ct:complex-type SampTimeBasedSelector { if-feature psampSampTimeBased; ct:extends Selector; description "Selector applying systematic time-based packet sampling to the packet stream."; reference "RFC5475, Section 5.1; RFC5476, Section 6.5.2.2."; leaf timeInterval { type uint32; units microseconds; mandatory true; description "The time interval in microseconds during which all arriving packets are sampled between gaps of length timeSpace. This parameter corresponds to the Information Element samplingTimeInterval."; reference "RFC5477, Section 8.2.4."; } leaf timeSpace { type uint32; units microseconds; mandatory true; description "The time interval in microseconds during which no packets are sampled between two sampling intervals specified by timeInterval. This parameter corresponds to the Information Element samplingTimeInterval."; reference "RFC5477, Section 8.2.5."; } } ct:complex-type SampRandOutOfNSelector { Linowski, et al. Expires April 22, 2011 [Page 53] Internet-Draft YANG Language Abstractions October 2010 if-feature psampSampRandOutOfN; ct:extends Selector; description "This container contains the configuration parameters of a Selector applying n-out-of-N packet sampling to the packet stream."; reference "RFC5475, Section 5.2.1; RFC5476, Section 6.5.2.3."; leaf size { type uint32; units packets; mandatory true; description "The number of elements taken from the parent population. This parameter corresponds to the Information Element samplingSize."; reference "RFC5477, Section 8.2.6."; } leaf population { type uint32; units packets; mandatory true; description "The number of elements in the parent population. This parameter corresponds to the Information Element samplingPopulation."; reference "RFC5477, Section 8.2.7."; } } ct:complex-type SampUniProbSelector { if-feature psampSampUniProb; ct:extends Selector; description "Selector applying uniform probabilistic packet sampling (with equal probability per packet) to the packet stream."; reference "RFC5475, Section 5.2.2.1; RFC5476, Section 6.5.2.4."; leaf probability { type decimal64 { fraction-digits 18; range "0..1"; } mandatory true; description "Probability that a packet is sampled, expressed as a value between 0 and 1. The probability is equal for every packet. This parameter corresponds to the Information Element samplingProbability."; Linowski, et al. Expires April 22, 2011 [Page 54] Internet-Draft YANG Language Abstractions October 2010 reference "RFC5477, Section 8.2.8."; } } ct:complex-type FilterMatchSelector { if-feature psampFilterMatch; ct:extends Selector; description "This container contains the configuration parameters of a Selector applying property match filtering to the packet stream."; reference "RFC5475, Section 6.1; RFC5476, Section 6.5.2.5."; choice nameOrId { mandatory true; description "The field to be matched is specified by either the name or the ID of the Information Element."; leaf ieName { type string; description "Name of the Information Element."; } leaf ieId { type uint16 { range "1..32767" { description "Valid range of Information Element identifiers."; reference "RFC5102, Section 4."; } } description "ID of the Information Element."; } } leaf ieEnterpriseNumber { type uint32; description "If present, ... "; } leaf value { type string; mandatory true; description "Matching value of the Information Element."; } } ct:complex-type FilterHashSelector { if-feature psampFilterHash; ct:extends Selector; description "This container contains the configuration parameters of a Selector applying hash-based filtering Linowski, et al. Expires April 22, 2011 [Page 55] Internet-Draft YANG Language Abstractions October 2010 to the packet stream."; reference "RFC5475, Section 6.2; RFC5476, Section 6.5.2.6."; leaf hashFunction { type identityref { base "hashFunction"; } default BOB; description "Hash function to be applied. According to RFC5475, Section 6.2.4.1, 'BOB' must be used in order to be compliant with PSAMP."; } leaf ipPayloadOffset { type uint64; units octets; default 0; description "IP payload offset ... "; reference "RFC5477, Section 8.3.2."; } leaf ipPayloadSize { type uint64; units octets; default 8; description "Number of IP payload bytes ... "; reference "RFC5477, Section 8.3.3."; } leaf digestOutput { type boolean; default false; description "If true, the output ... "; reference "RFC5477, Section 8.3.8."; } leaf initializerValue { type uint64; description "Initializer value to the hash function. If not configured by the user, the Monitoring Device arbitrarily chooses an initializer value."; reference "RFC5477, Section 8.3.9."; } list selectedRange { key name; min-elements 1; description "List of hash function return ranges for which packets are selected."; leaf name { type nameType; description "Key of this list."; } Linowski, et al. Expires April 22, 2011 [Page 56] Internet-Draft YANG Language Abstractions October 2010 leaf min { type uint64; description "Beginning of the hash function's selected range. This parameter corresponds to the Information Element hashSelectedRangeMin."; reference "RFC5477, Section 8.3.6."; } leaf max { type uint64; description "End of the hash function's selected range. This parameter corresponds to the Information Element hashSelectedRangeMax."; reference "RFC5477, Section 8.3.7."; } } } ct:complex-type Cache { ct:abstract true; description "Cache of a Monitoring Device."; key name; leaf name { type nameType; description "Key of a cache"; } leaf-list exportingProcess { type leafref { path "/ipfix/exportingProcess/name"; } description "Records are exported by all Exporting Processes in the list."; } description "Configuration and state parameters of a Cache."; container cacheLayout { description "Cache Layout."; list cacheField { key name; min-elements 1; description "List of fields in the Cache Layout."; leaf name { type nameType; description "Key of this list."; } choice nameOrId { mandatory true; description "Name or ID of the Information Element."; reference "RFC5102."; leaf ieName { type string; Linowski, et al. Expires April 22, 2011 [Page 57] Internet-Draft YANG Language Abstractions October 2010 description "Name of the Information Element."; } leaf ieId { type uint16 { range "1..32767" { description "Valid range of Information Element identifiers."; reference "RFC5102, Section 4."; } } description "ID of the Information Element."; } } leaf ieLength { type uint16; units octets; description "Length of the field ... "; reference "RFC5101, Section 6.2; RFC5102."; } leaf ieEnterpriseNumber { type uint32; description "If present, the Information Element is enterprise-specific. ... "; reference "RFC5101; RFC5102."; } leaf isFlowKey { when "(../../../cacheMode != 'immediate') and ((count(../ieEnterpriseNumber) = 0) or (../ieEnterpriseNumber != 29305))" { description "This parameter is not available for Reverse Information Elements (which have enterprise number 29305) or if the Cache Mode is 'immediate'."; } type empty; description "If present, this is a flow key."; } } } leaf dataRecords { type yang:counter64; units "Data Records"; config false; description "The number of Data Records generated ... "; reference "ietf-draft-ipfix-mib-10, Section 8 (ipfixMeteringProcessDataRecords)."; Linowski, et al. Expires April 22, 2011 [Page 58] Internet-Draft YANG Language Abstractions October 2010 } leaf cacheDiscontinuityTime { type yang:date-and-time; config false; description "Timestamp of the ... "; reference "ietf-draft-ipfix-mib-10, Section 8 (ipfixMeteringProcessDiscontinuityTime)."; } } ct:complex-type ImmediateCache { if-feature cacheModeImmediate; ct:extends Cache; } ct:complex-type NonImmediateCache { ct:abstract true; ct:extends Cache; leaf maxFlows { type uint32; units flows; description "This parameter configures the maximum number of Flows in the Cache ... "; } leaf activeFlows { type yang:gauge32; units flows; config false; description "The number of Flows currently active in this Cache."; reference "ietf-draft-ipfix-mib-10, Section 8 (ipfixMeteringProcessCacheActiveFlows)."; } leaf unusedCacheEntries { type yang:gauge32; units flows; config false; description "The number of unused Cache entries in this Cache."; reference "ietf-draft-ipfix-mib-10, Section 8 (ipfixMeteringProcessCacheUnusedCacheEntries)."; } } ct:complex-type NonPermanentCache { ct:abstract true; ct:extends NonImmediateCache; Linowski, et al. Expires April 22, 2011 [Page 59] Internet-Draft YANG Language Abstractions October 2010 leaf activeTimeout { type uint32; units milliseconds; description "This parameter configures the time in milliseconds after which ... "; } leaf inactiveTimeout { type uint32; units milliseconds; description "This parameter configures the time in milliseconds after which ... "; } } ct:complex-type NaturalCache { if-feature cacheModeNatural; ct:extends NonPermanentCache; } ct:complex-type TimeoutCache { if-feature cacheModeTimeout; ct:extends NonPermanentCache; } ct:complex-type PermanentCache { if-feature cacheModePermanent; ct:extends NonImmediateCache; leaf exportInterval { type uint32; units milliseconds; description "This parameter configures the interval for periodical export of Flow Records in milliseconds. If not configured by the user, the Monitoring Device sets this parameter."; } } ct:complex-type ExportDestination { ct:abstract true; description "Abstract export destination."; key name; leaf name { type nameType; description "Key of an export destination."; } } ct:complex-type IpDestination { Linowski, et al. Expires April 22, 2011 [Page 60] Internet-Draft YANG Language Abstractions October 2010 ct:abstract true; ct:extends ExportDestination; description "IP export destination."; leaf ipfixVersion { type uint16; default 10; description "IPFIX version number."; } leaf destinationPort { type inet:port-number; description "If not configured by the user, the Monitoring Device uses the default port number for IPFIX, which is 4739 without transport layer security and 4740 if transport layer security is activated."; } choice indexOrName { description "Index or name of the interface ... "; reference "RFC 1229."; leaf ifIndex { type uint32; description "Index of an interface as stored in the ifTable of IF-MIB."; reference "RFC 1229."; } leaf ifName { type string; description "Name of an interface as stored in the ifTable of IF-MIB."; reference "RFC 1229."; } } leaf sendBufferSize { type uint32; units bytes; description "Size of the socket send buffer. If not configured by the user, this parameter is set by the Monitoring Device."; } leaf rateLimit { type uint32; units "bytes per second"; description "Maximum number of bytes per second ... "; reference "RFC5476, Section 6.3"; } container transportLayerSecurity { presence "If transportLayerSecurity is present, DTLS is enabled if the transport protocol is SCTP or UDP, and TLS is enabled if the transport protocol is TCP."; Linowski, et al. Expires April 22, 2011 [Page 61] Internet-Draft YANG Language Abstractions October 2010 description "Transport layer security configuration."; uses transportLayerSecurityParameters; } container transportSession { config false; description "State parameters of the Transport Session directed to the given destination."; uses transportSessionParameters; } } ct:complex-type SctpExporter { ct:extends IpDestination; description "SCTP exporter."; leaf-list sourceIPAddress { type inet:ip-address; description "List of source IP addresses used ... "; reference "RFC 4960 (multi-homed SCTP endpoint)."; } leaf-list destinationIPAddress { type inet:ip-address; min-elements 1; description "One or multiple IP addresses ... "; reference "RFC 4960 (multi-homed SCTP endpoint)."; } leaf timedReliability { type uint32; units milliseconds; default 0; description "Lifetime in milliseconds ... "; reference "RFC 3758; RFC 4960."; } } ct:complex-type UdpExporter { ct:extends IpDestination; if-feature udpTransport; description "UDP parameters."; leaf sourceIPAddress { type inet:ip-address; description "Source IP address used by the Exporting Process ..."; } leaf destinationIPAddress { type inet:ip-address; mandatory true; description "IP address of the Collection Process to which IPFIX Messages are sent."; Linowski, et al. Expires April 22, 2011 [Page 62] Internet-Draft YANG Language Abstractions October 2010 } leaf maxPacketSize { type uint16; units octets; description "This parameter specifies the maximum size of IP packets ... "; } leaf templateRefreshTimeout { type uint32; units seconds; default 600; description "Sets time after which Templates are resent in the UDP Transport Session. ... "; reference "RFC5101, Section 10.3.6; RFC5815, Section 8 (ipfixTransportSessionTemplateRefreshTimeout)."; } leaf optionsTemplateRefreshTimeout { type uint32; units seconds; default 600; description "Sets time after which Options Templates are resent in the UDP Transport Session. ... "; reference "RFC5101, Section 10.3.6; RFC5815, Section 8 (ipfixTransportSessionOptionsTemplateRefreshTimeout)."; } leaf templateRefreshPacket { type uint32; units "IPFIX Messages"; description "Sets number of IPFIX Messages after which Templates are resent in the UDP Transport Session. ... "; reference "RFC5101, Section 10.3.6; RFC5815, Section 8 (ipfixTransportSessionTemplateRefreshPacket)."; } leaf optionsTemplateRefreshPacket { type uint32; units "IPFIX Messages"; description "Sets number of IPFIX Messages after which Options Templates are resent in the UDP Transport Session protocol. ... "; reference "RFC5101, Section 10.3.6; RFC5815, Section 8 (ipfixTransportSessionOptionsTemplateRefreshPacket)."; } } ct:complex-type TcpExporter { ct:extends IpDestination; if-feature tcpTransport; description "TCP exporter"; Linowski, et al. Expires April 22, 2011 [Page 63] Internet-Draft YANG Language Abstractions October 2010 leaf sourceIPAddress { type inet:ip-address; description "Source IP address used by the Exporting Process..."; } leaf destinationIPAddress { type inet:ip-address; mandatory true; description "IP address of the Collection Process to which IPFIX Messages are sent."; } } ct:complex-type FileWriter { ct:extends ExportDestination; if-feature fileWriter; description "File Writer."; leaf ipfixVersion { type uint16; default 10; description "IPFIX version number."; } leaf file { type inet:uri; mandatory true; description "URI specifying the location of the file."; } leaf bytes { type yang:counter64; units octets; config false; description "The number of bytes written by the File Writer..."; } leaf messages { type yang:counter64; units "IPFIX Messages"; config false; description "The number of IPFIX Messages written by the File Writer. ... "; } leaf discardedMessages { type yang:counter64; units "IPFIX Messages"; config false; description "The number of IPFIX Messages that could not be written by the File Writer ... "; } Linowski, et al. Expires April 22, 2011 [Page 64] Internet-Draft YANG Language Abstractions October 2010 leaf records { type yang:counter64; units "Data Records"; config false; description "The number of Data Records written by the File Writer. ... "; } leaf templates { type yang:counter32; units "Templates"; config false; description "The number of Template Records (excluding Options Template Records) written by the File Writer. ... "; } leaf optionsTemplates { type yang:counter32; units "Options Templates"; config false; description "The number of Options Template Records written by the File Writer. ... "; } leaf fileWriterDiscontinuityTime { type yang:date-and-time; config false; description "Timestamp of the most recent occasion at which one or more File Writer counters suffered a discontinuity. ... "; } list template { config false; description "This list contains the Templates and Options Templates that have been written by the File Reader. ... "; uses templateParameters; } } ct:complex-type ExportingProcess { if-feature exporter; description "Exporting Process of the Monitoring Device."; key name; leaf name { type nameType; description "Key of this list."; } leaf exportMode { type identityref { base "exportMode"; Linowski, et al. Expires April 22, 2011 [Page 65] Internet-Draft YANG Language Abstractions October 2010 } default parallel; description "This parameter determines to which configured destination(s) the incoming Data Records are exported."; } ct:instance-list destination { ct:instance-type ExportDestination; min-elements 1; description "Export destinations."; } list options { key name; description "List of options reported by the Exporting Process."; leaf name { type nameType; description "Key of this list."; } leaf optionsType { type identityref { base "optionsType"; } mandatory true; description "Type of the exported options data."; } leaf optionsTimeout { type uint32; units milliseconds; description "Time interval for periodic export of the options data. ... "; } } } ct:complex-type CollectingProcess { description "A Collecting Process."; key name; leaf name { type nameType; description "Key of a collecing process."; } ct:instance-list sctpCollector { ct:instance-type SctpCollector; description "List of SCTP receivers (sockets) on which the Collecting Process receives IPFIX Messages."; } ct:instance-list udpCollector { if-feature udpTransport; Linowski, et al. Expires April 22, 2011 [Page 66] Internet-Draft YANG Language Abstractions October 2010 ct:instance-type UdpCollector; description "List of UDP receivers (sockets) on which the Collecting Process receives IPFIX Messages."; } ct:instance-list tcpCollector { if-feature tcpTransport; ct:instance-type TcpCollector; description "List of TCP receivers (sockets) on which the Collecting Process receives IPFIX Messages."; } ct:instance-list fileReader { if-feature fileReader; ct:instance-type FileReader; description "List of File Readers from which the Collecting Process reads IPFIX Messages."; } leaf-list exportingProcess { type instance-identifier { ct:instance-type ExportingProcess; } description "Export of received records without any modifications. Records are processed by all Exporting Processes in the list."; } } ct:complex-type Collector { ct:abstract true; description "Abstract collector."; key name; leaf name { type nameType; description "Key of collectors"; } } ct:complex-type IpCollector { ct:abstract true; ct:extends Collector; description "Collector for IP transport protocols."; leaf localPort { type inet:port-number; description "If not configured, the Monitoring Device uses the default port number for IPFIX, which is 4739 without transport layer security and 4740 if transport layer security is activated."; } container transportLayerSecurity { presence "If transportLayerSecurity is present, DTLS is enabled if the transport protocol is SCTP or UDP, and TLS is enabled Linowski, et al. Expires April 22, 2011 [Page 67] Internet-Draft YANG Language Abstractions October 2010 if the transport protocol is TCP."; description "Transport layer security configuration."; uses transportLayerSecurityParameters; } list transportSession { config false; description "This list contains the currently established Transport Sessions terminating at the given socket."; uses transportSessionParameters; } } ct:complex-type SctpCollector { ct:extends IpCollector; description "Collector listening on aSCTP socket"; leaf-list localIPAddress { type inet:ip-address; description "List of local IP addresses ... "; reference "RFC 4960 (multi-homed SCTP endpoint)."; } } ct:complex-type UdpCollector { ct:extends IpCollector; description "Parameters of a listening UDP socket at a Collecting Process."; leaf-list localIPAddress { type inet:ip-address; description "List of local IP addresses on which the Collecting Process listens for IPFIX Messages."; } leaf templateLifeTime { type uint32; units seconds; default 1800; description "Sets the lifetime of Templates for all UDP Transport Sessions ... "; reference "RFC5101, Section 10.3.7; RFC5815, Section 8 (ipfixTransportSessionTemplateRefreshTimeout)."; } leaf optionsTemplateLifeTime { type uint32; units seconds; default 1800; description "Sets the lifetime of Options Templates for all UDP Transport Sessions terminating at this UDP socket. ... "; reference "RFC5101, Section 10.3.7; RFC5815, Section 8 Linowski, et al. Expires April 22, 2011 [Page 68] Internet-Draft YANG Language Abstractions October 2010 (ipfixTransportSessionOptionsTemplateRefreshTimeout)."; } leaf templateLifePacket { type uint32; units "IPFIX Messages"; description "If this parameter is configured, Templates defined in a UDP Transport Session become invalid if ..."; reference "RFC5101, Section 10.3.7; RFC5815, Section 8 (ipfixTransportSessionTemplateRefreshPacket)."; } leaf optionsTemplateLifePacket { type uint32; units "IPFIX Messages"; description "If this parameter is configured, Options Templates defined in a UDP Transport Session become invalid if ..."; reference "RFC5101, Section 10.3.7; RFC5815, Section 8 (ipfixTransportSessionOptionsTemplateRefreshPacket)."; } } ct:complex-type TcpCollector { ct:extends IpCollector; description "Collector listening on a TCP socket."; leaf-list localIPAddress { type inet:ip-address; description "List of local IP addresses on which the Collecting Process listens for IPFIX Messages."; } } ct:complex-type FileReader { ct:extends Collector; description "File Reading collector."; leaf file { type inet:uri; mandatory true; description "URI specifying the location of the file."; } leaf bytes { type yang:counter64; units octets; config false; description "The number of bytes read by the File Reader. ... "; } leaf messages { type yang:counter64; Linowski, et al. Expires April 22, 2011 [Page 69] Internet-Draft YANG Language Abstractions October 2010 units "IPFIX Messages"; config false; description "The number of IPFIX Messages read by the File Reader. ... "; } leaf records { type yang:counter64; units "Data Records"; config false; description "The number of Data Records read by the File Reader. ... "; } leaf templates { type yang:counter32; units "Templates"; config false; description "The number of Template Records (excluding Options Template Records) read by the File Reader. ..."; } leaf optionsTemplates { type yang:counter32; units "Options Templates"; config false; description "The number of Options Template Records read by the File Reader. ... "; } leaf fileReaderDiscontinuityTime { type yang:date-and-time; config false; description "Timestamp of the most recent occasion ... "; } list template { config false; description "This list contains the Templates and Options Templates that have been read by the File Reader. Withdrawn or invalidated (Options) Template MUST be removed from this list."; uses templateParameters; } } ct:complex-type SelectionProcess { description "Selection Process"; key name; leaf name { type nameType; description "Key of a selection process."; } Linowski, et al. Expires April 22, 2011 [Page 70] Internet-Draft YANG Language Abstractions October 2010 ct:instance-list selector { ct:instance-type Selector; min-elements 1; ordered-by user; description "List of Selectors that define the action of the Selection Process on a single packet. The Selectors are serially invoked in the same order as they appear in this list."; } list selectionSequence { config false; description "This list contains the Selection Sequence IDs which are assigned by the Monitoring Device ... "; reference "RFC5476."; leaf observationDomainId { type uint32; description "Observation Domain ID for which the Selection Sequence ID is assigned."; } leaf selectionSequenceId { type uint64; description "Selection Sequence ID used in the Selection Sequence (Statistics) Report Interpretation."; } } leaf cache { type instance-identifier { ct:instance-type Cache; } description "Cache which receives the output of the Selection Process."; } } /***************************************************************** * Groupings *****************************************************************/ grouping transportLayerSecurityParameters { description "Transport layer security parameters."; leaf-list localCertificationAuthorityDN { type string; description "Distinguished names of certification authorities whose certificates may be used to identify the local endpoint."; } leaf-list localSubjectDN { type string; description "Distinguished names which may be used in the certificates to identify the local endpoint."; Linowski, et al. Expires April 22, 2011 [Page 71] Internet-Draft YANG Language Abstractions October 2010 } leaf-list localSubjectFQDN { type inet:domain-name; description "Fully qualified domain names which may be used to in the certificates to identify the local endpoint."; } leaf-list remoteCertificationAuthorityDN { type string; description "Distinguished names of certification authorities whose certificates are accepted to authorize remote endpoints."; } leaf-list remoteSubjectDN { type string; description "Distinguished names which are accepted in certificates to authorize remote endpoints."; } leaf-list remoteSubjectFQDN { type inet:domain-name; description "Fully qualified domain name which are accepted in certificates to authorize remote endpoints."; } } grouping templateParameters { description "State parameters of a Template used by an Exporting Process or received by a Collecting Process ... "; reference "RFC5101; RFC5815, Section 8 (ipfixTemplateEntry, ipfixTemplateDefinitionEntry, ipfixTemplateStatsEntry)"; leaf observationDomainId { type uint32; description "The ID of the Observation Domain for which this Template is defined."; reference "RFC5815, Section 8 (ipfixTemplateObservationDomainId)."; } leaf templateId { type uint16 { range "256..65535" { description "Valid range of Template IDs."; reference "RFC5101"; } } description "This number indicates the Template Id in the IPFIX message."; reference "RFC5815, Section 8 (ipfixTemplateId)."; } leaf setId { Linowski, et al. Expires April 22, 2011 [Page 72] Internet-Draft YANG Language Abstractions October 2010 type uint16; description "This number indicates the Set ID of the Template. ... "; reference "RFC5815, Section 8 (ipfixTemplateSetId)."; } leaf accessTime { type yang:date-and-time; description "Used for Exporting Processes, ... "; reference "RFC5815, Section 8 (ipfixTemplateAccessTime)."; } leaf templateDataRecords { type yang:counter64; description "The number of transmitted or received Data Records ... "; reference "RFC5815, Section 8 (ipfixTemplateDataRecords)."; } leaf templateDiscontinuityTime { type yang:date-and-time; description "Timestamp of the most recent occasion at which the counter templateDataRecords suffered a discontinuity. ... "; reference "RFC5815, Section 8 (ipfixTemplateDiscontinuityTime)."; } list field { description "This list contains the (Options) Template fields of which the (Options) Template is defined. ... "; leaf ieId { type uint16 { range "1..32767" { description "Valid range of Information Element identifiers."; reference "RFC5102, Section 4."; } } description "This parameter indicates the Information Element Id of the field."; reference "RFC5815, Section 8 (ipfixTemplateDefinitionIeId); RFC5102."; } leaf ieLength { type uint16; units octets; description "This parameter indicates the length of the Information Element of the field."; reference "RFC5815, Section 8 (ipfixTemplateDefinitionIeLength); RFC5102."; Linowski, et al. Expires April 22, 2011 [Page 73] Internet-Draft YANG Language Abstractions October 2010 } leaf ieEnterpriseNumber { type uint32; description "This parameter indicates the IANA enterprise number of the authority ... "; reference "RFC5815, Section 8 (ipfixTemplateDefinitionIeEnterpriseNumber)."; } leaf isFlowKey { when "../../setId = 2" { description "This parameter is available for non-Options Templates (Set ID is 2)."; } type empty; description "If present, this is a Flow Key field."; reference "RFC5815, Section 8 (ipfixTemplateDefinitionFlags)."; } leaf isScope { when "../../setId = 3" { description "This parameter is available for Options Templates (Set ID is 3)."; } type empty; description "If present, this is a scope field."; reference "RFC5815, Section 8 (ipfixTemplateDefinitionFlags)."; } } } grouping transportSessionParameters { description "State parameters of a Transport Session ... "; reference "RFC5101, RFC5815, Section 8 (ipfixTransportSessionEntry, ipfixTransportSessionStatsEntry)"; leaf ipfixVersion { type uint16; description "Used for Exporting Processes, this parameter contains the version number of the IPFIX protocol ... "; reference "RFC5815, Section 8 (ipfixTransportSessionIpfixVersion)."; } leaf sourceAddress { type inet:ip-address; description "The source address of the Exporter of the IPFIX Transport Session... "; reference "RFC5815, Section 8 Linowski, et al. Expires April 22, 2011 [Page 74] Internet-Draft YANG Language Abstractions October 2010 (ipfixTransportSessionSourceAddressType, ipfixTransportSessionSourceAddress)."; } leaf destinationAddress { type inet:ip-address; description "The destination address of the Collector of the IPFIX Transport Session... "; reference "RFC5815, Section 8 (ipfixTransportSessionDestinationAddressType, ipfixTransportSessionDestinationAddress)."; } leaf sourcePort { type inet:port-number; description "The transport protocol port number of the Exporter of the IPFIX Transport Session."; reference "RFC5815, Section 8 (ipfixTransportSessionSourcePort)."; } leaf destinationPort { type inet:port-number; description "The transport protocol port number of the Collector of the IPFIX Transport Session... "; reference "RFC5815, Section 8 (ipfixTransportSessionDestinationPort)."; } leaf sctpAssocId { type uint32; description "The association id used for the SCTP session between the Exporter and the Collector ... "; reference "RFC5815, Section 8 (ipfixTransportSessionSctpAssocId), RFC3871"; } leaf status { type transportSessionStatus; description "Status of the Transport Session."; reference "RFC5815, Section 8 (ipfixTransportSessionStatus)."; } leaf rate { type yang:gauge32; units "bytes per second"; description "The number of bytes per second transmitted by the Exporting Process or received by the Collecting Process. This parameter is updated every second."; reference "RFC5815, Section 8 (ipfixTransportSessionRate)."; } leaf bytes { type yang:counter64; Linowski, et al. Expires April 22, 2011 [Page 75] Internet-Draft YANG Language Abstractions October 2010 units bytes; description "The number of bytes transmitted by the Exporting Process or received by the Collecting Process ... "; reference "RFC5815, Section 8 (ipfixTransportSessionBytes)."; } leaf messages { type yang:counter64; units "IPFIX Messages"; description "The number of messages transmitted by the Exporting Process or received by the Collecting Process... "; reference "RFC5815, Section 8 (ipfixTransportSessionMessages)."; } leaf discardedMessages { type yang:counter64; units "IPFIX Messages"; description "Used for Exporting Processes, this parameter indicates the number of messages that could not be sent ..."; reference "RFC5815, Section 8 (ipfixTransportSessionDiscardedMessages)."; } leaf records { type yang:counter64; units "Data Records"; description "The number of Data Records transmitted ... "; reference "RFC5815, Section 8 (ipfixTransportSessionRecords)."; } leaf templates { type yang:counter32; units "Templates"; description "The number of Templates transmitted by the Exporting Process or received by the Collecting Process. ... "; reference "RFC5815, Section 8 (ipfixTransportSessionTemplates)."; } leaf optionsTemplates { type yang:counter32; units "Options Templates"; description "The number of Option Templates transmitted by the Exporting Process or received by the Collecting Process..."; reference "RFC5815, Section 8 (ipfixTransportSessionOptionsTemplates)."; } leaf transportSessionStartTime { Linowski, et al. Expires April 22, 2011 [Page 76] Internet-Draft YANG Language Abstractions October 2010 type yang:date-and-time; description "Timestamp of the start of the given Transport Session... "; } leaf transportSessionDiscontinuityTime { type yang:date-and-time; description "Timestamp of the most recent occasion at which one or more of the Transport Session counters suffered a discontinuity... "; reference "RFC5815, Section 8 (ipfixTransportSessionDiscontinuityTime)."; } list template { description "This list contains the Templates and Options Templates that are transmitted by the Exporting Process or received by the Collecting Process. Withdrawn or invalidated (Options) Template MUST be removed from this list."; uses templateParameters; } } /***************************************************************** * Main container *****************************************************************/ container ipfix { description "Top-level node of the IPFIX/PSAMP configuration data model."; ct:instance-list collectingProcess { if-feature collector; ct:instance-type CollectingProcess; } ct:instance-list observationPoint { if-feature meter; ct:instance-type ObservationPoint; } ct:instance-list selectionProcess { if-feature meter; ct:instance-type SelectionProcess; } ct:instance-list cache { if-feature meter; description "Cache of the Monitoring Device."; Linowski, et al. Expires April 22, 2011 [Page 77] Internet-Draft YANG Language Abstractions October 2010 ct:instance-type Cache; } ct:instance-list exportingProcess { if-feature exporter; description "Exporting Process of the Monitoring Device."; ct:instance-type ExportingProcess; } } } Authors' Addresses Bernd Linowski TCS/Nokia Siemens Networks Heltorfer Strasse 1 Duesseldorf 40472 Germany EMail: bernd.linowski@ext.nsn.com Mehmet Ersue Nokia Siemens Networks St.-Martin-Strasse 53 Munich 81541 Germany EMail: mehmet.ersue@nsn.com Siarhei Kuryla 360 Treasury Systems Grueneburgweg 16-18 Frankfurt am Main 60322 Germany EMail: s.kuryla@gmail.com Linowski, et al. Expires April 22, 2011 [Page 78]