Network Working Group A. Clemm Internet-Draft Cisco Intended status: Experimental H. Ananthakrishnan Expires: August 18, 2014 Juniper Networks J. Medved T. Tkacik Cisco R. Varga Pantheon Technologies SRO N. Bahadur Bracket Computing February 14, 2014 A YANG Data Model for Network Topologies draft-clemm-i2rs-yang-network-topo-00.txt Abstract This document defines a YANG data model for network topologies. 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 August 18, 2014. Copyright Notice Copyright (c) 2014 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 Clemm, et al. Expires August 18, 2014 [Page 1] Internet-Draft draft-clemm-i2rs-yang-network-topo-00.txt February 2014 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. This document may contain material from IETF Documents or IETF Contributions published or made publicly available before November 10, 2008. The person(s) controlling the copyright in some of this material may not have granted the IETF Trust the right to allow modifications of such material outside the IETF Standards Process. Without obtaining an adequate license from the person(s) controlling the copyright in such materials, this document may not be modified outside the IETF Standards Process, and derivative works of it may not be created outside the IETF Standards Process, except to format it for publication as an RFC or to translate it into languages other than English. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Definitions and Acronyms . . . . . . . . . . . . . . . . . . 4 3. Network topology model overview . . . . . . . . . . . . . . . 5 3.1. Model structure . . . . . . . . . . . . . . . . . . . . . 5 3.2. Base model: Network Topology . . . . . . . . . . . . . . 6 3.2.1. Main building blocks . . . . . . . . . . . . . . . . 7 3.2.2. Discussion and selected design decisions . . . . . . 8 3.2.3. Open issues and items for further discussion . . . . 9 3.3. Extension of the model with specific topologies . . . . . 10 3.3.1. Layer 3 Unicast - IGP . . . . . . . . . . . . . . . . 10 3.3.2. OSPF Topology . . . . . . . . . . . . . . . . . . . . 12 3.3.3. IS-IS Topology . . . . . . . . . . . . . . . . . . . 15 3.3.4. TED - Traffic Engineering Data . . . . . . . . . . . 17 4. Network Topology YANG module . . . . . . . . . . . . . . . . 17 5. Layer 3 Unicast IGP Topology YANG Module . . . . . . . . . . 24 6. OSPF Topology YANG Module . . . . . . . . . . . . . . . . . . 29 7. ISIS Topology YANG Module . . . . . . . . . . . . . . . . . . 33 8. TED YANG Module . . . . . . . . . . . . . . . . . . . . . . . 36 9. Security Considerations . . . . . . . . . . . . . . . . . . . 42 10. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 42 11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 43 12. References . . . . . . . . . . . . . . . . . . . . . . . . . 43 12.1. Normative References . . . . . . . . . . . . . . . . . . 43 12.2. Informative References . . . . . . . . . . . . . . . . . 43 Clemm, et al. Expires August 18, 2014 [Page 2] Internet-Draft draft-clemm-i2rs-yang-network-topo-00.txt February 2014 1. Introduction This document introduces a YANG [RFC6020] [RFC6021] data model for network topologies. The model allows an application to have a holistic view of the topology of an entire network, all contained in a single conceptual YANG datastore. The data model builds on and is derived from the information model for network topologies defined in [topology-im]. In order to capture information that is specific to of a particular type of network topology, the basic model can be augmented and adapted. As a result, the data model is generic in nature and can be applied to many network topologies. For this reason, it is suitable for use as a general YANG data model framework to capture network topologies that go beyond the types that are introduced here. Specific topology types that are covered in this document include Layer 3 Unicast IGP, IS-IS [RFC1195], and OSPF [RFC2178]. Adaptations and extensions to other types of topologies are possible, using similar model patterns to the ones that are illustrated. The data model is generic in nature and can be applied to any type of network topology. There are multiple applications for such a data model. For example, within the context of I2RS, nodes within the network can use the data model to capture their understanding of the overall network topology and expose it to a network controller. A network controller can then use the instantiated topology data to compare and reconcile its own view of the network topology with that of the network elements that it controls. Alternatively, nodes within the network could propagate this understanding to compare and reconcile this understanding either amongs themselves or with help of a controller. Beyond the network element and the immediate context of I2RS itself, a network controller might even use the data model to represent its view of the topology that it controls and expose it to applications north of itself. Further use cases that the data model can be applied to are described in [topology-use-cases]. There are several reasons to choose YANG to define the data model. Data defined using YANG can be exposed by a server to client applications and controllers via Netconf [RFC6241] or via a ReST Interface [restconf] [yang-json]. The fact that it can be used with different protocols and interfaces provides for a degree of "future- proofing" of model implementations. Also, YANG can serve as the basis for model-driven toolchains, such as used in the Open Daylight project, in which this model has also been implemented. The data model is defined in several YANG modules: Clemm, et al. Expires August 18, 2014 [Page 3] Internet-Draft draft-clemm-i2rs-yang-network-topo-00.txt February 2014 o Module "network-topology" contains a generic network topology model. It defines a network topology at its most general level of abstraction. It models aspects such as the nodes and edges that a topology graph is composed of, as well as termination points contained in the nodes that actually terminate the edges of the graph. A network can contain multiple topologies, for example topologies at different layers and overlay topologies. The model therefore allows also to capture the relationship between topologies, as well as the dependencies between nodes and termination points across topologies. o Module "l3-unicast-igp-topology" applies the general network topology model to Layer 3 Unicast IGP topologies. It augments the general topology with information specific to Layer 3 Unicast IGP. In doing so, it also illustrates the extension patterns associated with extending respectively augmenting the general topology model to meet the needs of a specific topology. o Module "ospf-topology" defines a topology model for OSPF, building on and extending the Layer 3 Unicast IGP topology model. It serves as an example of how the general topology model can be refined across multiple levels. o Module "isis-topology" defines a topology model for IS-IS, again building on and extending the Layer 3 Unicast IGP topology model. o Module "ted", finally, is a helper module, defining information kept in the Traffic Engineering Database (TED) that is leveraged by IS-IS and OSPF topologies. 2. Definitions and Acronyms Datastore: A conceptual store of instantiated management information, with individual data items represented by data nodes which are arranged in hierarchical manner. Data subtree: An instantiated data node and the data nodes that are hierarchically contained within it. HTTP: Hyper-Text Transfer Protocol IGP: Interior Gateway Protocol IS-IS: Intermediate System to Intermediate System protocol LSP: Label Switched Path NETCONF: Network Configuration Protocol Clemm, et al. Expires August 18, 2014 [Page 4] Internet-Draft draft-clemm-i2rs-yang-network-topo-00.txt February 2014 OSPF: Open Shortest Path First, a link state routing protocol URI: Uniform Resource Identifier ReST: Representational State Transfer, a style of stateless interface and protocol that is generally carried over HTTP SRLG: Shared Risk Link Group TED: Traffic Engineering Database YANG: A data definition language for NETCONF 3. Network topology model overview This section provides an overview of the network topology model. We start with the structure of the foundational model that represents a generic topology. Subsequently, an overview of the specific topologies is given - Layer 3 Unicast IGP, OSPF, and IS-IS, respectively. During the course of the discussion, sected design choices are explained and the pattern that should be applied to extend the model to new types of topologies is presented. 3.1. Model structure The network topology model is defined by the following YANG modules, whose relationship is roughly depicted in the figure below. +-----------------------+ | network-topology | +-----------+-----------+ ^ | | +-----------^-------------+ | l3-unicast-igp-topology | +----+---------------+----+ ^ ^ | | | | +--------^-----+ +-----^---------+ +--------+ | ospf-topology| | isis-topology | | ted | +--------^-----+ +-----^---------+ +----v---+ : : : :...............:...................: Figure 1: Overall model structure Clemm, et al. Expires August 18, 2014 [Page 5] Internet-Draft draft-clemm-i2rs-yang-network-topo-00.txt February 2014 YANG module network-topology defines the basic network topology model. YANG module l3-unicast-igp-topology builds on top of this model, augmenting network-topology with additional definitions needed to represent Layer 3 Unicast IGP topologies. This module in turn is augmented by YANG modules with additional definitions for OSPF and for IS-IS topologies, ospf-topology and isis-topology, respectively. Finally, YANG module "ted" contains a set of auxiliary definitions used by both ospf-topology and isis-topology, capturing data related to traffic engineering. 3.2. Base model: Network Topology The structure of the network topology data model, as later defined in the YANG module "network-topology", is depicted in the following diagram. Brackets enclose list keys, "rw" means configuration data, "ro" means operational state data, and "?" designates optional nodes. The figure does not depict all definitions; it is intended to illustrate the overall structure. module: network-topology +--rw network-topology +--rw topology [topology-id] +--rw topology-id topology-id +--ro server-provided? boolean +--rw topology-types +--rw underlay-topology [topology-ref] | +--rw topology-ref topology-ref +--rw node [node-id] | +--rw node-id node-id | +--rw supporting-node [node-ref] | | +--rw node-ref node-ref | +--rw termination-point [tp-id] | +--rw tp-id tp-id | +--ro tp-ref* tp-ref +--rw link [link-id] +--rw link-id link-id +--rw source | +--rw source-node node-ref | +--rw source-tp? tp-ref +--rw destination | +--rw dest-node node-ref | +--rw dest-tp? tp-ref +--rw supporting-link [link-ref] +--rw link-ref link-ref Clemm, et al. Expires August 18, 2014 [Page 6] Internet-Draft draft-clemm-i2rs-yang-network-topo-00.txt February 2014 3.2.1. Main building blocks A network can contain multiple topologies. Each topology is captured in its own list element, distinguished via a topology-id. This is captured by list "topology", contained underneath the root container for this module, "network-topology". A topology has a certain type, such as OSPF or IS-IS. A topology can even have multiple types simultaneously. The type, or types, are captured underneath container "topology-types". This serves as container for data nodes that represent specific topology types. In this module, it serves merely as an augmentation target; topology- specific modules will later introduce new data nodes to represent new topology types below this target, i.e. insert them below "topology- types" by ways of augmentation. Topology types SHOULD always be represented using containers, not leafs of empty type. This allows to represent hierarchies of topology subtypes within the instance information. For example, an instance of an OSPF topology (which, at the same time, is a layer 3 unicast IGP topology) would contain underneath "topology-types" another container "l3-unicast-igp-topology", which in turn would contain a container "ospf-topology". A topology can in turn be part of a hierarchy of topologies, building on top of other topologies. Any such topologies are captured in list "underlay-topology". Furthermore, a topology contains nodes and links, each captured in their own list. A node has a node-id. This distinguishes the node from other nodes in the list. In addition, a node has a list of termination points, used to terminate links. An examples of a termination point might be a physical or logical port or, more generally, an interface. Also, a node can in turn map onto other nodes in an underlay topology. This is captured in list "supporting-node". A link is identified by a link-id, uniquely identifying the link within the topology. Links are point-to-point and unidirectional. Accordingly, a link contains a source and a destination. Both source and destination reference a corresponding node, as well as a termination point on that node. Analogous to a node, a link can in turn map onto other links an underlay topology. This is captured in list "supporting-link". Clemm, et al. Expires August 18, 2014 [Page 7] Internet-Draft draft-clemm-i2rs-yang-network-topo-00.txt February 2014 3.2.2. Discussion and selected design decisions Rather than maintaining lists in separate containers, the model is kept relatively flat in terms of its containment structure. This way, path specifiers used to refer to specific nodes, be it in management operations or in specifications of constraints, can remain relatively compact. Of course, this means there is no separate structure in instance information that separates elements of different lists from one another. Such structure is semantically not required, although it might enhance human readability in some cases. In an effort to minimize assumptions of what a topology might actually represent, mappings between topologies, nodes, links, and termination points are kept strictly generic. For example, no assumptions are made whether a termination point actually refers to an interface, or whether a node refers to a specific "system" or device; the model at this generic level makes no provisions for that. Any greater specifics about mappings between upper and lower layers can be captured in augmenting modules. For example, if a termination point maps to an interface, an augmenting module can augment the termination point with a leaf that references the corresponding interface [if-config]. If a node maps to a particular device or network element, an augmenting module can augment node with a leaf that references the network element. The model makes extensive use of groupings, instead of simply defining data nodes "in-line". This allows to more easily include the corresponding data nodes in notifications, which then do not need to respecify each data node that is to be included. The tradeoff for this is that it makes the specification of constraints more complex, because constraints involving data nodes outside the grouping need to be specified in conjunction with a "uses" statement where the grouping is applied. This also means that constraints and XPath- statmeents need to specified in such a way that the navigate "down" first and select entire sets of nodes, as opposed to being able to simply specify them against individual data nodes. The topology model includes links that are point-to-point and unidirectional. It does not directly support multipoint and bidirectional links. While this may appear as a limitation, it does keep the model simple, generic, and allows it to very easily be subjected applications that make use of graph algorithms. Birectional conections can be represented through pairs of unidirectional links. By introducing hierarchies of nodes, with nodes at one level mapping onto a set of other nodes at another level, and the introducing new links for nodes at that level, topologies with connections representing non-point-to-point communication patterns can be represented. Clemm, et al. Expires August 18, 2014 [Page 8] Internet-Draft draft-clemm-i2rs-yang-network-topo-00.txt February 2014 Links are terminated by a single termination point, not sets of termination points. Connections involving multihoming or link aggregation schemes need to be represented using multiple point-to- point links, then defining a link at a higher layer that is supported by those individual links. In a hierarchy of topologies, there are nodes mapping to nodes, links mapping to links, and termination points mapping to termination points. Some of this information is redundant. Specifically, with the link-to-links mapping known, and the termination points of each link known, maintaining separate termination point mapping information is not needed but can be derived via transitive closure. The model does provide for the option to include this information explicitly, but does not allow for it to be configured to avoid the potential to introduce (and having to validate) corresponding integrity issues. A topology's topology types are represented using a container which contains a data node for each of its topology types. A topology can encompass several types of topology simultaneously, hence a container is used instead of a case construct, with each topology type in turn represented by a dedicated presence container itself. The reason for not simply using an empty leaf, or even simpler, do away even with the topology container and just use a leaf-list of topology-type instead, is to be able to represent "class hierarchies" of topology types, with one topology type refining the other. Topology-type specific containers are to be defined in the topology-specific modules, augmenting the topology-types container. 3.2.3. Open issues and items for further discussion YANG requires data needs to be designated as either configuration or operational data, but not both, yet it is important to have all topology information, including vertical cross-topology dependencies, captured in one coherent model. In most cases topology information is discovered about a network; the topology is considered a property of the network that is reflected in the model. That said, it is conceivable that certain types of topology need to also be configurable by an application. There are several alternatives in which this can be addressed. The alternative chosen in this draft does not restrict topology information as read-only, but includes a flag that indicates for each topology whether it should be considered as read-only or configurable by applications. An alternative would be to designate topology list elements as read only. The read-only topology list includes each topology; it is the Clemm, et al. Expires August 18, 2014 [Page 9] Internet-Draft draft-clemm-i2rs-yang-network-topo-00.txt February 2014 complete reference. In parallel a second topology list is introduced. This list serves the purpose of being able to configure topologies which are then mirrored in the read-only list. The configurable topology list adheres to the same structure and uses the same groupings as its read-only counterpart. As most data is defined in those groupings, the amount of additional definitions required will be limited. A configurable topology will thus be represented twice: once in the read-only list of all topologies, a second time in a configuration sandbox. 3.3. Extension of the model with specific topologies 3.3.1. Layer 3 Unicast - IGP In order to represent a general Layer 3 Unicast IGP topology, the basic network topology model needs to be extended. The corresponding extensions are introduced in a separate YANG module "l3-unicast-igp- topology". The structure of those extensions is depicted in the following diagram. Brackets enclose list keys, "rw" means configuration, "ro" operational state data, "?" designates optional nodes, "*" designates nodes that can have multiple instances. Parantheses enclose choice and case nodes. Data nodes from the network-topology module are omitted (indicated by "....."), as long as not required to indicate containment structure. Notifications are not depicted. Clemm, et al. Expires August 18, 2014 [Page 10] Internet-Draft draft-clemm-i2rs-yang-network-topo-00.txt February 2014 module: network-topology +--rw network-topology +--rw topology [topology-id] +..... +--rw topology-types | +--rw l3t:l3-unicast-igp-topology? ..... +--rw node [node-id] | ..... | +--rw termination-point [tp-id] | | ..... | | +--rw l3t:igp-termination-point-attributes | | +--rw (termination-point-type)? | | +--:(ip) | | | +--rw l3t:ip-address* inet:ip-address | | +--:(unnumbered) | | +--rw l3t:unnumbered-id? uint32 | +--rw l3t:igp-node-attributes | +--rw l3t:name? inet:domain-name | +--rw l3t:flag* flag-type | +--rw l3t:router-id* inet:ip-address | +--rw l3t:prefix [prefix] | +--rw l3t:prefix inet:ip-prefix | +--rw l3t:metric? uint32 | +--rw l3t:flag* flag-type +--rw link [link-id] | ..... | +--rw l3t:igp-link-attributes | +--rw l3t:name? string | +--rw l3t:flag* flag-type | +--rw l3t:metric? uint32 +--rw l3t:igp-topology-attributes +--rw l3t:name? string +--rw l3t:flag* flag-type The module augments the original network-topology module as follows: o A new topology type is introduced, l3-unicast-igp-topology-type. This is represented by a container object, which is inserted under the "topology-types" container of the network topology module. o Additional topology attributes are introduced, defined in a grouping, which augments the "topology" list of the network topology module. The attributes include an IGP name, as well as a set of flags (represented through a leaf-list). Each type of flag is represented by a separate identity. This allows to introduce additional flags in augmenting modules that are associated with specific IGP topologies, without needing to revise this module. Clemm, et al. Expires August 18, 2014 [Page 11] Internet-Draft draft-clemm-i2rs-yang-network-topo-00.txt February 2014 o Additional data objects for nodes are introduced by augmenting the "node" list of the network topology module. New objects include again a set of flags, as well as a list of prefixes. Each prefix in turn includes an ip prefix, a metric, and a prefix-specific set of flags. o Links are augmented as well with a set of parameters, allowing to associate a link with an IGP name, another set of flags, and a link metric. In addition, the module defines a set of notifications to alert clients of any events concerning links, nodes, prefixes, and termination points. Each notification includes an indication of the type of event, the topology from which it originated, and the affected node, or link, or prefix, or termination point. In addition, as a convenience to applications, additional data of the affected node, or link, or termination point (respectively) is included. While this makes notifications larger in volume than they would need to be, it avoids the need for subsequent retrieval of context information, which also might have changed in the meantime. 3.3.2. OSPF Topology OSPF is the next type of topology represented in the model. OSPF represents a particular type of Layer 3 Unicast IGP. Accordingly, this time the Layer 3 Unicast IGP topology model needs to be extended. The corresponding extensions are introduced in a separate YANG module "ospf-topology", whose structure is depicted in the following diagram. For the most part, this module augments "l3 -unicast-igp-topology". Like before, brackets enclose list keys, "rw" means configuration, "ro" operational state data, "?" designates optional nodes, "*" designates nodes that can have multiple instances. Parantheses enclose choice and case nodes. Data nodes from the network-topology module are omitted (indicated by "....."), as long as not required to indicate containment structure. Notifications are not depicted. module: network-topology +--rw network-topology +--rw topology [topology-id] ..... +--rw topology-types | +--rw l3t:l3-unicast-igp-topology? | +--rw ospf:ospf? ..... +--rw node [node-id] | ..... | +--rw l3t:igp-node-attributes Clemm, et al. Expires August 18, 2014 [Page 12] Internet-Draft draft-clemm-i2rs-yang-network-topo-00.txt February 2014 | ..... | +--rw l3t:prefix [prefix] | | +..... | | +--rw ospf:ospf-prefix-attributes | | +--rw ospf:forwarding-address? inet:ipv4-address | +--rw ospf:ospf-node-attributes | | +--rw (router-type)? | | | +--:(abr) | | | | +--rw ospf:abr? empty | | | +--:(asbr) | | | | +--rw ospf:asbr? empty | | | +--:(internal) | | | | +--rw ospf:internal? empty | | | +--:(pseudonode) | | | +--rw ospf:pseudonode? empty | | +--rw ospf:dr-interface-id? uint32 | | +--rw ospf:multi-topology-id* uint8 | | +--rw ospf:capabilities? bits | | +--rw ospf:ted | | +--rw ospf:te-router-id-ipv4? inet:ipv4-address | | +--rw ospf:te-router-id-ipv6? inet:ipv6-address | | +--rw ospf:ipv4-local-address [ipv4-prefix] | | | +--rw ospf:ipv4-prefix inet:ipv4-prefix | | +--rw ospf:ipv6-local-address [ipv6-prefix] | | | +--rw ospf:ipv6-prefix inet:ipv6-prefix | | | +--rw ospf:prefix-option? uint8 | | +--rw ospf:pcc-capabilities? pcc-capabilities | ..... +--rw link [link-id] | ..... | +--rw l3t:igp-link-attributes | ..... | +--rw ospf:ospf-link-attributes | | +--rw ospf:multi-topology-id? uint8 | | +--rw ospf:ted | | +--rw ospf:color? uint32 | | +--rw ospf:max-link-bandwidth? decimal64 | | +--rw ospf:max-resv-link-bandwidth? decimal64 | | +--rw ospf:unreserved-bandwidth [priority] | | | +--rw ospf:priority uint8 | | | +--rw ospf:bandwidth? decimal64 | | +--rw ospf:te-default-metric? uint32 | | +--rw ospf:srlg | | +--rw ospf:interface-switching-capabilities [switching-capability] | | | +--rw ospf:switching-capability ted:switching-capabilities | | | +--rw ospf:encoding? uint8 | | | +--rw ospf:max-lsp-bandwidth [priority] | | | | +--rw ospf:priority uint8 Clemm, et al. Expires August 18, 2014 [Page 13] Internet-Draft draft-clemm-i2rs-yang-network-topo-00.txt February 2014 | | | | +--rw ospf:bandwidth? decimal64 | | | +--rw ospf:packet-switch-capable | | | | +--rw ospf:minimum-lsp-bandwidth? decimal64 | | | | +--rw ospf:interface-mtu? uint16 | | | +--rw ospf:time-division-multiplex-capable | | | +--rw ospf:minimum-lsp-bandwidth? decimal64 | | | +--rw ospf:indication? uint16 | | +--rw ospf:srlg-values [srlg-value] | | | +--rw ospf:srlg-value uint32 | | +--rw ospf:link-protection-type? uint16 | ..... +--rw l3t:igp-topology-attributes ..... +--rw ospf:ospf-topology-attributes | +--rw ospf:area-id? area-id ..... The module augments "l3-unicast-igp-topology" as follows: o A new topology type for an OSPF topology is introduced. This is represented by a container object, which is inserted under the "l3 -unicast-igp-topology" container of the l3-unicast-igp-topology module. This way, an ospf topology represents both a l3-unicast- igp topology and an ospf topology. o Additional topology attributes are defined in a new grouping which augments igp-topology-attributes of the l3-unicast-igp-topology module. The attributes include an OSPF area-id identifying the OSPF area. o Additional data objects for nodes are introduced by augmenting the igp-node-attributes of the l3-unicast-igp-topology module. New objects include router-type, de-interface-id for pseudonodes, list of multi-topology-ids, ospf node capabilities and traffic engineering attributes. o Links are augmented with a multi-topology-id and traffic engineering link attributes. o Prefixes are augmented with OSPF specific forwarding address. In addition, the module extends IGP node, link and prefix notifications with OSPF attributes. Clemm, et al. Expires August 18, 2014 [Page 14] Internet-Draft draft-clemm-i2rs-yang-network-topo-00.txt February 2014 3.3.3. IS-IS Topology IS-IS is another type of Layer 3 Unicast IGP. Like OSPF topology, IS-IS topology is defined in a separate module, "isis-topology", which augments "l3-unicast-igp-topology". The structure is depicted in the following diagram. Like before, brackets enclose list keys, "rw" means configuration, "ro" operational state data, "?" designates optional nodes, "*" designates nodes that can have multiple instances. Parantheses enclose choice and case nodes. Data nodes from the network-topology module are omitted (indicated by "....."), as long as not required to indicate containment structure. Notifications are not depicted. module: network-topology +--rw network-topology +--rw topology [topology-id] ..... | +--rw l3t:l3-unicast-igp-topology? | ..... | +--rw isis:isis? ..... +--rw node [node-id] ..... | +--rw l3t:igp-node-attributes | ..... | +--rw isis:isis-node-attributes | +--rw isis:iso | | +--rw isis:iso-system-id? iso-system-id | | +--rw isis:iso-pseudonode-id? iso-pseudonode-id | +--rw isis:net* iso-net-id | +--rw isis:multi-topology-id* uint8 | +--rw (router-type)? | | +--:(level-2) | | | +--rw isis:level-2? empty | | +--:(level-1) | | | +--rw isis:level-1? empty | | +--:(level-1-2) | | +--rw isis:level-1-2? empty | +--rw isis:ted | +--rw isis:te-router-id-ipv4? inet:ipv4-address | +--rw isis:te-router-id-ipv6? inet:ipv6-address | +--rw isis:ipv4-local-address [ipv4-prefix] | | +--rw isis:ipv4-prefix inet:ipv4-prefix | +--rw isis:ipv6-local-address [ipv6-prefix] | | +--rw isis:ipv6-prefix inet:ipv6-prefix | | +--rw isis:prefix-option? uint8 | +--rw isis:pcc-capabilities? pcc-capabilities +--rw link [link-id] Clemm, et al. Expires August 18, 2014 [Page 15] Internet-Draft draft-clemm-i2rs-yang-network-topo-00.txt February 2014 | ..... | +--rw l3t:igp-link-attributes | ..... | +--rw isis:isis-link-attributes | +--rw isis:multi-topology-id? uint8 | +--rw isis:ted | +--rw isis:color? uint32 | +--rw isis:max-link-bandwidth? decimal64 | +--rw isis:max-resv-link-bandwidth? decimal64 | +--rw isis:unreserved-bandwidth [priority] | | +--rw isis:priority uint8 | | +--rw isis:bandwidth? decimal64 | +--rw isis:te-default-metric? uint32 | +--rw isis:srlg | +--rw isis:interface-switching-capabilities [switching-capability] | | +--rw isis:switching-capability ted:switching-capabilities | | +--rw isis:encoding? uint8 | | +--rw isis:max-lsp-bandwidth [priority] | | | +--rw isis:priority uint8 | | | +--rw isis:bandwidth? decimal64 | | +--rw isis:packet-switch-capable | | | +--rw isis:minimum-lsp-bandwidth? decimal64 | | | +--rw isis:interface-mtu? uint16 | | +--rw isis:time-division-multiplex-capable | | +--rw isis:minimum-lsp-bandwidth? decimal64 | | +--rw isis:indication? uint16 | +--rw isis:srlg-values [srlg-value] | | +--rw isis:srlg-value uint32 | +--rw isis:link-protection-type? uint16 +--rw l3t:igp-topology-attributes ...... +--rw isis:isis-topogloy-attributes +--rw isis:net? iso-net-id The module augments the l3-unicast-igp-topology as follows: o A new topology type is introduced, "isis-topology-type". This is represented by a container object, which is inserted under the "l3 -unicast-igp-topology" container of the l3-unicast-igp-topology module. This way, an isis topology represents both a l3-unicast- igp-topology and an isis topology. o Additional topology attributes are introduced in a new grouping which augments "igp-topology-attributes" of the l3-unicast-igp- topology module. The attributes include an ISIS NET-id identifying the area. Clemm, et al. Expires August 18, 2014 [Page 16] Internet-Draft draft-clemm-i2rs-yang-network-topo-00.txt February 2014 o Additional data objects for nodes are introduced by augmenting "igp-node-attributes" of the l3-unicast-igp-topology module. New objects include router-type, iso-system-id to identify the router, a list of multi-topology-id, a list of NET ids, and traffic engineering attributes. o Links are augmented with multi-topology-id and traffic engineering link attributes. In addition, the module augments IGP nodes and links with ISIS attributes. 3.3.4. TED - Traffic Engineering Data Traffic Engineering Data is required both by OSPF and IS-IS, which are defined in separate modules. Information shared by both is defined in another module, "ted". This module defines a set of groupings with auxiliary information required and shared by those other modules. This module details traffic-engineering node and link attributes: o TED node attributes include te-router-id for IPv4 and IPv6, local IPv4 and IPv6 addresses and path computation client capabilities. The path computation client capabilities in turn include a bit vector for various path computation capabilities. o TED link attributes comprise link color, max-link-bandwidth, max- resv-link-bandwidth, unreserved bandwidth and re-metric. They also include SRLG attributes which contains interface switching capabilities, a list of SRLG values, and a link protection type. The interface switching capabilities in turn contain a list element for each switching capability, defining encoding, max-lsp- bandwidth, and interface switching specific attributes. 4. Network Topology YANG module file "network-topology@2013-10-21.yang" module network-topology { yang-version 1; namespace "urn:TBD:params:xml:ns:yang:network-topology"; // replace with IANA namespace when assigned prefix "nt"; import ietf-inet-types { prefix "inet"; } organization "TBD"; Clemm, et al. Expires August 18, 2014 [Page 17] Internet-Draft draft-clemm-i2rs-yang-network-topo-00.txt February 2014 contact "WILL-BE-DEFINED-LATER"; description "This module defines a model for the topology of a network. Key design decisions are as follows: A topology consists of a set of nodes and links. Links are point-to-point and unidirectional. Bidirectional connections need to be represented through two separate links. Multipoint connections, broadcast domains etc can be represented through a hierarchy of nodes, then connecting nodes at upper layers of the hierarchy."; revision 2013-10-21 { description "Initial revision."; } typedef topology-id { type inet:uri; description "An identifier for a topology."; } typedef node-id { type inet:uri; description "An identifier for a node in a topology. The identifier may be opaque. The identifier SHOULD be chosen such that the same node in a real network topology will always be identified through the same identifier, even if the model is instantiated in separate datastores. An implementation MAY choose to capture semantics in the identifier, for example to indicate the type of node and/or the type of topology that the node is a part of."; } typedef link-id { type inet:uri; description "An identifier for a link in a topology. The identifier may be opaque. The identifier SHOULD be chosen such that the same link in a real network topology will always be identified through the same identifier, even if the model is instantiated in separate datastores. An implementation MAY choose to capture semantics in the identifier, for example to indicate the type of link and/or the type of topology that the link is a part of."; Clemm, et al. Expires August 18, 2014 [Page 18] Internet-Draft draft-clemm-i2rs-yang-network-topo-00.txt February 2014 } typedef tp-id { type inet:uri; description "An identifier for termination points on a node. The identifier may be opaque. The identifier SHOULD be chosen such that the same TP in a real network topology will always be identified through the same identifier, even if the model is instantiated in separate datastores. An implementation MAY choose to capture semantics in the identifier, for example to indicate the type of TP and/or the type of node and topology that the TP is a part of."; } typedef tp-ref { type leafref { path "/network-topology/topology/node/termination-point/tp-id"; } description "A type for an absolute reference to a termination point. (This type should not be used for relative references. In such a case, a relative path should be used instead.)"; } typedef topology-ref { type leafref { path "/network-topology/topology/topology-id"; } description "A type for an absolute reference a topology instance."; } typedef node-ref { type leafref { path "/network-topology/topology/node/node-id"; } description "A type for an absolute reference to a node instance. (This type should not be used for relative references. In such a case, a relative path should be used instead.)"; } typedef link-ref { type leafref { path "/network-topology/topology/link/link-id"; } description "A type for an absolute reference a link instance. Clemm, et al. Expires August 18, 2014 [Page 19] Internet-Draft draft-clemm-i2rs-yang-network-topo-00.txt February 2014 (This type should not be used for relative references. In such a case, a relative path should be used instead.)"; } grouping tp-attributes { description "The data objects needed to define a termination point. (This only includes a single leaf at this point, used to identify the termination point.) Provided in a grouping so that in addition to the datastore, the data can also be included in notifications."; leaf tp-id { type tp-id; } leaf-list tp-ref { type tp-ref; config false; description "The leaf list identifies any termination points that the termination point is dependent on, or maps onto. Those termination points will themselves be contained in a supporting node. This dependency information can be inferred from the dependencies between links. For this reason, this item is not separately configurable. Hence no corresponding constraint needs to be articulated. The corresponding information is simply provided by the implementing system."; } } grouping node-attributes { description "The data objects needed to define a node. The objects are provided in a grouping so that in addition to the datastore, the data can also be included in notifications as needed."; leaf node-id { type node-id; description "The identifier of a node in the topology. A node is specific to a topology to which it belongs."; } list supporting-node { description "This list defines vertical layering information for nodes. It allows to capture for any given node, which node (or nodes) in the corresponding underlay topology it maps onto. Clemm, et al. Expires August 18, 2014 [Page 20] Internet-Draft draft-clemm-i2rs-yang-network-topo-00.txt February 2014 A node can map to zero, one, or more nodes below it; accordingly there can be zero, one, or more elements in the list. If there are specific layering requirements, for example specific to a particular type of topology that only allows for certain layering relationships, the choice below can be augmented with additional cases. A list has been chosen rather than a leaf-list in order to provide room for augmentations, e.g. for statistics or priorization information associated with supporting nodes."; key "node-ref"; leaf node-ref { type node-ref; } } } grouping link-attributes { // This is a grouping, not defined inline with the link definition itself, // so it can be included in a notification, if needed leaf link-id { type link-id; description "The identifier of a link in the topology. A link is specific to a topology to which it belongs."; } container source { leaf source-node { mandatory true; type node-ref; description "Source node identifier, must be in same topology."; } leaf source-tp { type tp-ref; description "Termination point within source node that terminates the link."; } } container destination { leaf dest-node { mandatory true; type node-ref; description "Destination node identifier, must be in same topology."; } leaf dest-tp { type tp-ref; Clemm, et al. Expires August 18, 2014 [Page 21] Internet-Draft draft-clemm-i2rs-yang-network-topo-00.txt February 2014 description "Termination point within destination node that terminates the link."; } } list supporting-link { key "link-ref"; leaf link-ref { type link-ref; } } } container network-topology { list topology { description " This is the model of an abstract topology. A topology contains nodes and links. Each topology MUST be identified by unique topology-id for reason that a network could contain many topologies. "; key "topology-id"; leaf topology-id { type topology-id; description " It is presumed that a datastore will contain many topologies. To distinguish between topologies it is vital to have UNIQUE topology identifiers. "; } leaf server-provided { type boolean; config false; description " Indicates whether the topology is configurable by clients, or whether it is provided by the server. This leaf is populated by the server implementing the model. It is set to false for topologies that are created by a client; it is set to true otherwise. If it is set to true, any attempt to edit the topology MUST be rejected. "; } container topology-types { description "This container is used to identify the type, or types (as a topology can support several types simultaneously), of the topology. Clemm, et al. Expires August 18, 2014 [Page 22] Internet-Draft draft-clemm-i2rs-yang-network-topo-00.txt February 2014 Topology types are the subject of several integrity constraints that an implementing server can validate in order to maintain integrity of the datastore. Topology types are indicated through separate data nodes; the set of topology types is expected to increase over time. To add support for a new topology, an augmenting module needs to augment this container with a new empty optional container to indicate the new topology type. The use of a container allows to indicate a subcategorization of topology types. The container SHALL NOT be augmented with any data nodes that serve a purpose other than identifying a particular topology type. "; } list underlay-topology { key "topology-ref"; leaf topology-ref { type topology-ref; } // a list, not a leaf-list, to allow for potential augmentation // with properties specific to the underlay topology, // such as statistics, preferences, or cost. description "Identifies the topology, or topologies, that this topology is dependent on."; } list node { description "The list of network nodes defined for the topology."; key "node-id"; uses node-attributes; must "boolean(../underlay-topology[*]/node[./supporting-nodes/node-ref])"; // This constraint is meant to ensure that a referenced node is in fact // a node in an underlay topology. list termination-point { description "A termination point can terminate a link. Depending on the type of topology, a termination point could, for example, refer to a port or an interface."; key "tp-id"; uses tp-attributes; } } list link { description " A Network Link connects a by Local (Source) node and Clemm, et al. Expires August 18, 2014 [Page 23] Internet-Draft draft-clemm-i2rs-yang-network-topo-00.txt February 2014 a Remote (Destination) Network Nodes via a set of the nodes' termination points. As it is possible to have several links between the same source and destination nodes, and as a link could potentially be re-homed between termination points, to ensure that we would always know to distinguish between links, every link is identified by a dedicated link identifier. Note that a link models a point-to-point link, not a multipoint link. Layering dependencies on links in underlay topologies are not represented as the layering information of nodes and of termination points is sufficient. "; key "link-id"; uses link-attributes; must "boolean(../underlay-topology/link[./supporting-link]"; // Constraint: any supporting link must be part of an underlay topology must "boolean(../node[./source/source-node])"; // Constraint: A link must have as source a node of the same topology must "boolean(../node[./destination/dest-node])"; // Constraint: A link must have as source a destination of the same topology must "boolean(../node/termination-point[./source/source-tp])"; // Constraint: The source termination point must be contained in the source node must "boolean(../node/termination-point[./destination/dest-tp])"; // Constraint: The destination termination point must be contained // in the destination node } } } } 5. Layer 3 Unicast IGP Topology YANG Module file "l3-unicast-igp-topology@2013-10-21.yang" module l3-unicast-igp-topology { yang-version 1; namespace "urn:TBD:params:xml:ns:yang:nt:l3-unicast-igp-topology"; // replace with IANA namespace when assigned prefix "l3t"; import network-topology { prefix "nt"; } import ietf-inet-types { prefix "inet"; Clemm, et al. Expires August 18, 2014 [Page 24] Internet-Draft draft-clemm-i2rs-yang-network-topo-00.txt February 2014 } organization "TBD"; contact "TBD"; revision "2013-10-21" { description "Initial revision"; reference "TBD"; } typedef igp-event-type { description "IGP Event type for notifications"; type enumeration { enum "add" { value 0; description "An IGP node or link or prefix or termination-point has been added"; } enum "remove" { value 1; description "An IGP node or link or prefix or termination-point has been removed"; } enum "update" { value 2; description "An IGP node or link or prefix or termination-point has been updated"; } } } // igp-event-type identity flag-identity { description "Base type for flags"; } identity undefined-flag { base "flag-identity"; } typedef flag-type { type identityref { base "flag-identity"; } } grouping igp-prefix-attributes { leaf prefix { type inet:ip-prefix; } leaf metric { type uint32; } Clemm, et al. Expires August 18, 2014 [Page 25] Internet-Draft draft-clemm-i2rs-yang-network-topo-00.txt February 2014 leaf-list flag { type flag-type; } } grouping l3-unicast-igp-topology-type { container l3-unicast-igp-topology { presence "indicates L3 Unicast IGP Topology"; } } grouping igp-topology-attributes { container igp-topology-attributes { leaf name { description "Name of the topology"; type string; } leaf-list flag { description "Topology flags"; type flag-type; } } } grouping igp-node-attributes { container igp-node-attributes { leaf name { description "Node name"; type inet:domain-name; } leaf-list flag { description "Node operational flags"; type flag-type; } leaf-list router-id { description "Router-id for the node"; type inet:ip-address; } list prefix { key "prefix"; uses igp-prefix-attributes; } } } grouping igp-link-attributes { container igp-link-attributes { leaf name { Clemm, et al. Expires August 18, 2014 [Page 26] Internet-Draft draft-clemm-i2rs-yang-network-topo-00.txt February 2014 description "Link Name"; type string; } leaf-list flag { description "Link flags"; type flag-type; } leaf metric { description "Link Metric"; type uint32 { range "0..16777215" { description " "; // OSPF/ISIS supports max 3 byte metric. // Ideally we would like this restriction to be // defined in the derived models, however, // we are not allowed to augment a "must" statement. } } } } } // grouping igp-link-attributes grouping igp-termination-point-attributes { container igp-termination-point-attributes { choice termination-point-type { case ip { leaf-list ip-address { description "IPv4 or IPv6 address"; type inet:ip-address; } } case unnumbered { leaf unnumbered-id { description "Unnumbered interface identifier"; type uint32; } } } } } // grouping igp-termination-point-attributes augment "/nt:network-topology/nt:topology/nt:topology-types" { uses l3-unicast-igp-topology-type; } augment "/nt:network-topology/nt:topology" { Clemm, et al. Expires August 18, 2014 [Page 27] Internet-Draft draft-clemm-i2rs-yang-network-topo-00.txt February 2014 when "nt:topology-types/l3-unicast-igp-topology"; uses igp-topology-attributes; } augment "/nt:network-topology/nt:topology/nt:node" { when "../nt:topology-types/l3-unicast-igp-topology"; uses igp-node-attributes; } augment "/nt:network-topology/nt:topology/nt:link" { when "../nt:topology-types/l3-unicast-igp-topology"; uses igp-link-attributes; } augment "/nt:network-topology/nt:topology/nt:node/nt:termination-point" { when "../../nt:topology-types/l3-unicast-igp-topology"; uses igp-termination-point-attributes; } notification igp-node-event { leaf igp-event-type { type igp-event-type; } leaf topology-ref { type nt:topology-ref; } uses l3-unicast-igp-topology-type; uses nt:node-attributes; uses igp-node-attributes; } notification igp-link-event { leaf igp-event-type { type igp-event-type; } leaf topology-ref { type nt:topology-ref; } uses l3-unicast-igp-topology-type; uses nt:link-attributes; uses igp-link-attributes; } notification igp-prefix-event { leaf igp-event-type { type igp-event-type; } leaf topology-ref { type nt:topology-ref; } Clemm, et al. Expires August 18, 2014 [Page 28] Internet-Draft draft-clemm-i2rs-yang-network-topo-00.txt February 2014 leaf node-ref { type nt:node-ref; } uses l3-unicast-igp-topology-type; container prefix { uses igp-prefix-attributes; } } notification termination-point-event { leaf igp-event-type { type igp-event-type; } leaf topology-ref { type nt:topology-ref; } leaf node-ref { type nt:node-ref; } uses l3-unicast-igp-topology-type; uses nt:tp-attributes; uses igp-termination-point-attributes; } } 6. OSPF Topology YANG Module file "ospf-topology@2013-10-21.yang" module ospf-topology { yang-version 1; namespace "urn:TBD:params:xml:ns:yang:ospf-topology"; // replace with IANA namespace when assigned prefix "ospf"; import network-topology { prefix "nt"; } import l3-unicast-igp-topology { prefix "l3t"; } import ietf-inet-types { prefix "inet"; } import ted { Clemm, et al. Expires August 18, 2014 [Page 29] Internet-Draft draft-clemm-i2rs-yang-network-topo-00.txt February 2014 prefix "ted"; } organization "TBD"; contact "TBD"; description "OSPF Topology model"; revision "2013-10-21" { description "Initial revision"; reference "TBD"; } typedef area-id { description "OSPF Area ID"; type uint32; } grouping ospf-topology-type { container ospf { presence "indiates OSPF Topology"; } } augment "/nt:network-topology/nt:topology/nt:topology-types/l3t:l3-unicast-igp-topology" { uses ospf-topology-type; } augment "/nt:network-topology/nt:topology/l3t:igp-topology-attributes" { when "../nt:topology-types/l3t:l3-unicast-igp-topology/ospf"; container ospf-topology-attributes { leaf area-id { type area-id; } } } augment "/nt:network-topology/nt:topology/nt:node/l3t:igp-node-attributes" { when "../../nt:topology-types/l3t:l3-unicast-igp-topology/ospf"; uses ospf-node-attributes; } augment "/nt:network-topology/nt:topology/nt:link/l3t:igp-link-attributes" { when "../../nt:topology-types/l3t:l3-unicast-igp-topology/ospf"; uses ospf-link-attributes; } augment "/nt:network-topology/nt:topology/nt:node/l3t:igp-node-attributes/l3t:prefix" { when "../../../nt:topology-types/l3t:l3-unicast-igp-topology/ospf"; Clemm, et al. Expires August 18, 2014 [Page 30] Internet-Draft draft-clemm-i2rs-yang-network-topo-00.txt February 2014 uses ospf-prefix-attributes; } grouping ospf-node-attributes { container ospf-node-attributes { choice router-type { case abr { leaf abr { type empty; } } case asbr { leaf asbr { type empty; } } case internal { leaf internal { type empty; } } case pseudonode { leaf pseudonode { type empty; } } } leaf dr-interface-id { when "../router-type/pseudonode"; description "For pseudonodes, DR interface-id"; default "0"; type uint32; } leaf-list multi-topology-id { description "List of Multi-Topology Identifier up-to 128 (0-127). RFC 4915"; max-elements "128"; type uint8 { range "0..127"; } } leaf capabilities { description "OSPF capabilities as bit vector. RFC 4970"; type bits { bit graceful-restart-capable { position 0; } bit graceful-restart-helper { position 1; Clemm, et al. Expires August 18, 2014 [Page 31] Internet-Draft draft-clemm-i2rs-yang-network-topo-00.txt February 2014 } bit stub-router-support { position 2; } bit traffic-engineering-support { position 3; } bit point-to-point-over-lan { position 4; } bit experimental-te { position 5; } } } container ted { uses ted:ted-node-attributes; } } // ospf } // ospf-node-attributes grouping ospf-link-attributes { container ospf-link-attributes { leaf multi-topology-id { type uint8 { range "0..127"; } } container ted { uses ted:ted-link-attributes; } } } // ospf-link-attributes grouping ospf-prefix-attributes { container ospf-prefix-attributes { leaf forwarding-address { when "../../l3t:l3-unicast-igp-topology/l3t:ospf/l3t:router-type/l3t:asbr"; type inet:ipv4-address; } } } augment "/l3t:igp-node-event" { uses ospf-topology-type; uses ospf:ospf-node-attributes; } Clemm, et al. Expires August 18, 2014 [Page 32] Internet-Draft draft-clemm-i2rs-yang-network-topo-00.txt February 2014 augment "/l3t:igp-link-event" { uses ospf-topology-type; uses ospf:ospf-link-attributes; } augment "/l3t:igp-prefix-event" { uses ospf-topology-type; uses ospf:ospf-prefix-attributes; } } 7. ISIS Topology YANG Module file "isis-topology@2013-10-21.yang" module isis-topology { yang-version 1; namespace "urn:TBD:params:xml:ns:yang:network:isis-topology"; // replace with IANA namespace when assigned prefix "isis"; import network-topology { prefix nt; } import l3-unicast-igp-topology { prefix igp; } import ted { prefix ted; } organization "TBD"; contact "TBD"; description "ISIS Topology model"; revision "2013-10-21" { description "Initial version"; } typedef iso-system-id { description "ISO System ID. RFC 1237"; type string { pattern '[0-9a-fA-F]{4}(\.[0-9a-fA-F]{4}){2}'; } } typedef iso-pseudonode-id { description "ISO pseudonode id for broadcast network"; Clemm, et al. Expires August 18, 2014 [Page 33] Internet-Draft draft-clemm-i2rs-yang-network-topo-00.txt February 2014 type string { pattern '[0-9a-fA-F]{2}'; } } typedef iso-net-id { description "ISO NET ID. RFC 1237"; type string { pattern '[0-9a-fA-F]{2}((\.[0-9a-fA-F]{4}){6})'; } } grouping isis-topology-type { container isis { presence "Indicates ISIS Topology"; } } augment "/nt:network-topology/nt:topology/nt:topology-types/igp:l3-unicast-igp-topology" { uses isis-topology-type; } augment "/nt:network-topology/nt:topology/igp:igp-topology-attributes" { when "../nt:topology-types/l3t:l3-unicast-igp-topology/isis"; container isis-topology-attributes { leaf net { type iso-net-id; } } } augment "/nt:network-topology/nt:topology/nt:node/igp:igp-node-attributes" { when "../../nt:topology-types/l3t:l3-unicast-igp-topology/isis"; uses isis-node-attributes; } augment "/nt:network-topology/nt:topology/nt:link/igp:igp-link-attributes" { when "../../nt:topology-types/l3t:l3-unicast-igp-topology/isis"; uses isis-link-attributes; } grouping isis-node-attributes { container isis-node-attributes { container iso { leaf iso-system-id { type iso-system-id; } leaf iso-pseudonode-id { default "0"; Clemm, et al. Expires August 18, 2014 [Page 34] Internet-Draft draft-clemm-i2rs-yang-network-topo-00.txt February 2014 type iso-pseudonode-id; } } leaf-list net { max-elements 3; type iso-net-id; } leaf-list multi-topology-id { description "List of Multi Topology Identifier upto 128 (0-127). RFC 4915"; max-elements "128"; type uint8 { range "0..127"; } } choice router-type { case level-2 { leaf level-2 { type empty; } } case level-1 { leaf level-1 { type empty; } } case level-1-2 { leaf level-1-2 { type empty; } } } container ted { uses ted:ted-node-attributes; } } } grouping isis-link-attributes { container isis-link-attributes { leaf multi-topology-id { type uint8 { range "0..127"; } } container ted { uses ted:ted-link-attributes; } } Clemm, et al. Expires August 18, 2014 [Page 35] Internet-Draft draft-clemm-i2rs-yang-network-topo-00.txt February 2014 } augment "/igp:igp-node-event" { uses isis-topology-type; uses isis-node-attributes; } augment "/igp:igp-link-event" { uses isis-topology-type; uses isis-link-attributes; } } // Module isis-topology 8. TED YANG Module file "ted@2013-10-21.yang" module ted { yang-version 1; namespace "urn:TBD:params:xml:ns:yang:network:ted"; // replace with IANA namespace when assigned prefix ted; import ietf-inet-types { prefix inet; } organization "TBD"; contact "TBD"; description "Helper module to hold TED attributes for OSPF/ISIS"; revision 2013-10-21 { description "Initial revision"; } typedef switching-capabilities { description "Switching Capabilities of an interface."; reference "RFC 5307: IS-IS Extensions in Support of Generalized Multi-Protocol Label Switching (GMPLS)"; type enumeration { enum "PSC-1" { Clemm, et al. Expires August 18, 2014 [Page 36] Internet-Draft draft-clemm-i2rs-yang-network-topo-00.txt February 2014 description "Packet-Switch Capable-1 (PSC-1)"; value 1; } enum "PSC-2" { description "Packet-Switch Capable-2 (PSC-2)"; value 2; } enum "PSC-3" { description "Packet-Switch Capable-3 (PSC-3)"; value 3; } enum "PSC-4" { description "Packet-Switch Capable-4 (PSC-4)"; value 4; } enum "L2SC" { description "Layer-2 Switch Capable (L2SC)"; value 51; } enum "TDM" { description "Time-Division-Multiplex Capable (TDM)"; value 100; } enum "LSC" { description "Lambda-Switch Capable (LSC)"; value 150; } enum "FSC" { description "Fiber-Switch Capable (FSC)"; value 200; } } } typedef pcc-capabilities { description "Path Computation Capabilities."; reference "RFC 5088, draft-ietf-pce-disco-protoc-isis-07.txt OSPF/ISIS Protocol Extensions for Path Computation Element (PCE) Discovery."; Clemm, et al. Expires August 18, 2014 [Page 37] Internet-Draft draft-clemm-i2rs-yang-network-topo-00.txt February 2014 type bits { bit path-computation-with-gmpls-link-constraints { position 0; } bit bidirectional-path-computation { position 1; } bit diverse-path-computation { position 2; } bit load-balanced-path-computation { position 3; } bit synchronized-path-computation { position 4; } bit support-for-multiple-objective-functions { position 5; } bit support-for-additive-path-constraints { position 6; } bit support-for-request-prioritization { position 7; } bit support-for-multiple-requests-per-message { position 8; } } } grouping ted-node-attributes { description "Identifier to uniquely identify a node in TED"; reference "RFC 5305, RFC 6119: IPv6 Traffic Engineering in IS-IS/OSPF"; leaf te-router-id-ipv4 { description "Globally unique IPv4 Traffic Engineering Router ID."; type inet:ipv4-address; } leaf te-router-id-ipv6 { description "Globally unique IPv6 Traffic Engineering Router ID"; type inet:ipv6-address; } list ipv4-local-address { description "List of IPv4 Local Address(OSPF). RFC 5786"; Clemm, et al. Expires August 18, 2014 [Page 38] Internet-Draft draft-clemm-i2rs-yang-network-topo-00.txt February 2014 key "ipv4-prefix"; leaf ipv4-prefix { description "Local IPv4 address for the node"; type inet:ipv4-prefix; } } list ipv6-local-address { description "List of IPv6 Local Address."; reference "RFC 5786: Advertising a Router's Local Addresses in OSPF Traffic Engineering (TE) Extensions"; key "ipv6-prefix"; leaf ipv6-prefix { description "Local IPv6 address for the node"; type inet:ipv6-prefix; } leaf prefix-option { description "IPv6 prefix option."; type uint8; } } leaf pcc-capabilities { description "OSPF/ISIS PCC capabilities"; type pcc-capabilities; } } grouping ted-link-attributes { description "TED Attributes associated with the link."; reference "RFC 3630, RFC 3784: IS-IS / OSPF Traffic Engineering (TE)"; leaf color { description "Administrative group or color of the link"; type uint32; } leaf max-link-bandwidth { description "Maximum bandwidth that can be see on this link in this direction. Units in bytes per second"; type decimal64 { fraction-digits 2; } } Clemm, et al. Expires August 18, 2014 [Page 39] Internet-Draft draft-clemm-i2rs-yang-network-topo-00.txt February 2014 leaf max-resv-link-bandwidth { description "Maximum amount of bandwidth that can be reserved in this direction in this link. Units in bytes per second"; type decimal64 { fraction-digits 2; } } list unreserved-bandwidth { description "Unreserved bandwidth for 0-7 priority levels. Units in bytes per second"; max-elements "8"; key "priority"; leaf priority { type uint8 { range "0..7"; } } leaf bandwidth { description "Unreserved bandwidth for this level"; type decimal64 { fraction-digits 2; } } } leaf te-default-metric { description "Traffic Engineering Metric"; type uint32; } container srlg { description "Shared Risk Link Group Attributes"; uses srlg-attributes; } } grouping srlg-attributes { description "Shared Risk Link Group Attributes"; reference "RFC 5307, RFC 4203: ISIS / OSPF Extensions in Support of Generalized Multi-Protocol Label Switching (GMPLS)"; list interface-switching-capabilities { description "List of interface capabilities for this interface"; key "switching-capability"; leaf switching-capability { Clemm, et al. Expires August 18, 2014 [Page 40] Internet-Draft draft-clemm-i2rs-yang-network-topo-00.txt February 2014 description "Switching Capability for this interface"; type ted:switching-capabilities; } leaf encoding { description "Encoding supported by this interface"; type uint8; } list max-lsp-bandwidth { description "Maximum LSP Bandwidth at priorities 0-7"; max-elements "8"; key "priority"; leaf priority { type uint8 { range "0..7"; } } leaf bandwidth { description "Max LSP Bandwidth for this level"; type decimal64 { fraction-digits 2; } } } container packet-switch-capable { when "../switching-capability = PSC-1 or ../switching-capability = PSC-2 or ../switching-capability = PSC-3 or ../switching-capability = PSC-4"; description "Interface has packet-switching capabilities"; leaf minimum-lsp-bandwidth { description "Minimum LSP Bandwidth. Units in bytes per second"; type decimal64 { fraction-digits 2; } } leaf interface-mtu { description "Interface MTU"; type uint16; } } container time-division-multiplex-capable { when "../switching-capability = TDM"; description "Interface has time-division multiplex capabilities"; Clemm, et al. Expires August 18, 2014 [Page 41] Internet-Draft draft-clemm-i2rs-yang-network-topo-00.txt February 2014 leaf minimum-lsp-bandwidth { description "Minimum LSP Bandwidth. Units in bytes per second"; type decimal64 { fraction-digits 2; } } leaf indication { description "Indication whether the interface supports Standard or Arbitrary SONET/SDH"; type uint16; } } } list srlg-values { description "List of Shared Risk Link Group this interface belongs to."; key "srlg-value"; leaf srlg-value { description "Shared Risk Link Group value"; type uint32; } } leaf link-protection-type { description "Link Protection Type desired for this link"; type uint16; } } } 9. Security Considerations The transport protocol used for sending the topology data MUST support authentication and SHOULD support encryption. The data-model by itself does not create any security implications. 10. Contributors The model presented in this paper was contributed to by more people than can be listed on the author list. Additional contributors include: o Ken Gray, Juniper Networks Clemm, et al. Expires August 18, 2014 [Page 42] Internet-Draft draft-clemm-i2rs-yang-network-topo-00.txt February 2014 o Tom Nadeau, Juniper Networks o Aleksandr Zhdankin, Cisco 11. Acknowledgements We wish to acknowledge the helpful contributions, comments, and suggestions that were received from Ladislav Lhotka, Andy Bierman, Carlos Pignataro, Juergen Schoenwaelder, and Alia Atlas. 12. References 12.1. Normative References [RFC1195] Callon, R., "Use of OSI IS-IS for Routing in TCP/IP and Dual Environments", RFC 1195, December 1990. [RFC2178] Moy, J., "OSPF Version 2", RFC 2178, July 1997. [RFC6020] Bjorklund, M., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, October 2010. [RFC6021] Schoenwaelder, J., "Common YANG Data Types", RFC 6021, October 2010. [RFC6241] Enns, R., Bjorklund, M., Schoenwaelder, J., and A. Bierman, "Network Configuration Protocol (NETCONF)", RFC 6241, June 2011. 12.2. Informative References [if-config] Bjorklund, M., "A YANG Data Model for Interface Management", I-D draft-ietf-netmod-interfaces-cfg-16, July 2013. [restconf] Bierman, A., Bjorklund, M., Watsen, K., and R. Fernando, "RESTCONF Protocol", I-D draft-bierman-netconf- restconf-04, February 2014. [topology-im] Medved, J., Bahadur, N., Clemm, A., and H. Ananthakrishnan, "An Information Model for Network Topologies", I-D draft-medved-i2rs-topology-im-01, October 2013. Clemm, et al. Expires August 18, 2014 [Page 43] Internet-Draft draft-clemm-i2rs-yang-network-topo-00.txt February 2014 [topology-use-cases] Medved, J., Previdi, S., Lopez, V., and S. Amante, "Topology API Use Cases", I-D draft-amante-i2rs-topology- use-cases-01, October 2013. [yang-json] Lhotka, L., "Modeling JSON Text with YANG", I-D draft- lhotka-etmod-yang-json-02, September 2013. Authors' Addresses Alexander Clemm Cisco EMail: alex@cisco.com Hariharan Ananthakrishnan Juniper Networks EMail: hanantha@juniper.net Jan Medved Cisco EMail: jmedved@cisco.com Tony Tkacik Cisco EMail: ttkacik@cisco.com Robert Varga Pantheon Technologies SRO EMail: robert.varga@pantheon.sk Nitin Bahadur Bracket Computing EMail: nitin_bahadur@yahoo.com Clemm, et al. Expires August 18, 2014 [Page 44]