YANG Data Models for 'Attachment Circuits'-as-a-Service (ACaaS)

YANG Data Models for 'Attachment Circuits'-as-a-Service (ACaaS) Orange

mohamed.boucadair@orange.com

Juniper

rroberts@juniper.net

Telefonica

oscar.gonzalezdedios@telefonica.com

Nokia

samier.barguil_giraldo@nokia.com

Huawei Technologies

lana.wubo@huawei.com

Operations and Management OPSAWG Slice Service L3VPN L2VPN This document specifies a YANG service data model for Attachment Circuits (ACs). This model can be used for the provisioning of ACs before or during service provisioning (e.g., Network Slice Service). The document also specifies a module that updates other service and network modules with the required information to bind specific services to ACs that are created using the AC service model. Also, the document specifies a set of reusable groupings. Whether other service models reuse structures defined in the AC models or simply include an AC reference is a design choice of these service models. Utilizing the AC service model to manage ACs over which a service is delivered has the advantage of decoupling service management from upgrading AC components to incorporate recent AC technologies or features. Discussion Venues Discussion of this document takes place on the Operations and Management Area Working Group Working Group mailing list (opsawg@ietf.org), which is archived at . Source for this draft and an issue tracker can be found at .

Introduction

Scope and Intended Use Connectivity services are provided by networks to customers via dedicated terminating points, such as Service Functions , customer edges (CEs), peer Autonomous System Border Routers (ASBRs), data centers gateways, or Internet Exchange Points. A connectivity service is basically about ensuring data transfer received from or destined to a given terminating point to or from other terminating points within the same customer/service, an interconnection node, or an ancillary node. The objectives for the connectivity service can be negotiated and agreed upon between the customer and the network provider. To facilitate data transfer within the provider network, it is assumed that the appropriate setup is provisioned over the links that connect customer terminating points and a provider network, allowing successfully data exchanged over these links. The required setup is referred to in this document as Attachment Circuits (ACs), while the underlying link is referred to as "bearers". This document adheres to the definition of an Attachment Circuit as provided in Section 1.2 of , especially:

Routers can be attached to each other, or to end systems, in a variety of different ways: PPP connections, ATM Virtual Circuits (VCs), Frame Relay VCs, ethernet interfaces, Virtual Local Area Networks (VLANs) on ethernet interfaces, GRE tunnels, Layer 2 Tunneling Protocol (L2TP) tunnels, IPsec tunnels, etc. We will use the term "attachment circuit" to refer generally to some such means of attaching to a router. An attachment circuit may be the sort of connection that is usually thought of as a "data link", or it may be a tunnel of some sort; what matters is that it be possible for two devices to be network layer peers over the attachment circuit.

When a customer requests a new value-added service, the service can be bound to existing attachment circuits or trigger the instantiation of new attachment circuits. The provisioning of a value-added service should, thus, accommodate both deployments. Also, because the instantiation of an attachment circuit requires coordinating the provisioning of endpoints that might not belong to the same administrative entity (customer vs. provider or distinct operational teams within the same provider, etc.), ** providing programmatic means to expose 'attachment circuits'-as-a-service will greatly simplify the provisioning of value-added services** delivered over an attachment circuits. This document specifies a YANG service data model ("ietf-ac-svc") for managing attachment circuits that are exposed by a network to its customers, such as an enterprise site, a network function, a hosting infrastructure, or a peer network provider. The model can be used for the provisioning of ACs prior or during advanced service provisioning (e.g., Network Slice Service). The "ietf-ac-svc" includes a set of reusable groupings. Whether a service model reuses structures defined in the "ietf-ac-svc" or simply includes an AC reference (that was communicated during AC service instantiation) is a design choice of these service models. Relying upon the AC service model to manage ACes over which services are delivered has the merit to decorrelate the management of the (core) service vs. upgrade the AC components to reflect recent AC technologies or new features (e.g., new encryption scheme, additional routing protocol). This document favors the approach of completely relying upon the AC service model instead of duplicating data nodes into specific modules of advanced services that are delivered over an Attachment Circuit. Since the provisioning of an AC requires a bearer to be in place, this document introduces a new module called "ietf-bearer-svc" that enables customers to manage their bearer requests. The customers can then retrieve a provider-assigned bearer reference that they will include in their AC service requests. An AC service request can provide a reference to a bearer or a set of peer SAPs. Both schemes are supported in the AC service model. Each AC is identified with a unique identifier within a (provider) domain. From a network provider standpoint, an AC can be bound to a single or multiple Service Attachment Points (SAPs) . Likewise, the same SAP can be bound to one or multiple ACs. However, the mapping between an AC and a PE in the provider network that terminates that AC is hidden to the application that makes use of the AC service model. Such mapping information is internal to the network controllers. As such, the details about the (node-specific) attachment interfaces are not exposed in the AC service model. The AC service model does not make any assumptions about the internal structure or even the nature or the services that will be delivered over an attachment circuit. Customers do not have access to that network view other than the ACes that the ordered. For example, the AC service model can be used to provision a set of ACes to connect multiple sites (Site1, Site2, ..., SiteX) for customer who also requested VPN services. If these provisioning of these services require specific configuration on ASBR nodes, such configuration is handled at the network level and is not exposed to the customer at the service level. However, the network controller will have access to such a view as the service points in these ASBRs will be exposed as SAPs with "role" set to "ietf-sap-ntw:nni" . The AC service model can be used in a variety of contexts, such as (but not limited to) those provided in :

Request an attachment circuit for a known peer SAP ().
Instantiate multiple attachment circuits over the same bearer ().
Control the precedence over multiple attachment circuits ().
Create Multiple ACs bound to Multiple CEs ().
Bind a slice service to a set of pre-provisioned attachment circuits ().
Connect a Cloud Infrastructure to a service provider network ().

The examples use the IPv4 address blocks reserved for documentation , the IPv6 prefix reserved for documentation , and the Autonomous System (AS) numbers reserved for documentation . The YANG data models in this document conform to the Network Management Datastore Architecture (NMDA) defined in .

Position ACaaS vs. Other Data Models The AC model specified in this document is not a network model . As such, the model does not expose details related to specific nodes in the provider's network that terminate an AC. The mapping between an AC as seen by a customer and the network implementation of an AC is maintained by the network controllers and is not exposed to the customer. This mapping can be maintained using a variety of network models, such as augmented SAP AC network model . The AC service model is not a device model. A network provider may use a variety of device models (e.g., Routing management or BGP ) to provision an AC service.

Why Not Using the L2SM as Reference Data Model for ACaaS? The L2SM covers some AC-related considerations. Nevertheless, the L2SM structure is primarily focused on Layer 2 aspects. For example, the L2SM part does not cover Layer 3 provisioning, which is required for the typical AC instantiation.

Why Not Using the L3SM as Reference Data Model for ACaaS? Like the L2SM, the L3SM addresses certain AC-related aspects. However, the L3SM structure does not sufficiently address layer 2 provisioning requirements. Additionally, the L3SM is primarily designed for conventional L3VPN deployments and, as such, has some limitations for instantiating ACs in other deployment contexts (e.g., cloud environments). For example, the L3SM does not provide the capability to provision multiple BGP sessions over the same AC.

Conventions and Definitions 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 when, and only when, they appear in all capitals, as shown here. The meanings of the symbols in the YANG tree diagrams are defined in . This document uses the following terms:

Bearer:: A physical or logical link that connects a customer node (or site) to a provider network. A bearer can be a wireless or wired link. One or multiple technologies can be used to build a bearer. The bearer type can be specified by a customer.
: The operator allocates a unique bearer reference to identify a bearer within its network (e.g., customer line identifier). Such a reference can be retrieved by a customer and used in subsequent service placement requests to unambiguously identify where a service is to be bound.
: The concept of bearer can be generalized to refer to the required underlying connection for the provisioning of an attachment circuit. One or multiple attachment circuits may be hosted over the same bearer (e.g., multiple VLANs on the same bearer that is provided by a physical link).
Network controller:: Denotes a functional entity responsible for the management of the service provider network.
Service orchestrator:: Refers to a functional entity that interacts with the customer of a network service. The service orchestrator is typically responsible for the attachment circuits, the Provider Edge (PE) selection, and requesting the activation of the requested service to a network controller.
Service provider network:: A network that is able to provide network services (e.g., Layer 2 VPN, Layer 3, and Network Slice Services).
Service provider:: A service provider that offers network services (e.g., Layer 2 VPN, Layer 3, and Network Slice Services).

Sample Uses of the Data Models

ACs Terminated by One or Multiple Customer Edges (CEs) depicts two target topology flavors that involve ACs. These topologies have the following characteristics:

A Customer Edges (CEs) can be either a physical device or a logical entity. Such logical entity is typically a software component (e.g., a virtual service function that is hosted within the provider's network or a third-party infrastructure). A CE is seen by the network as a peer SAP.
An AC service request may include one or multiple ACs, which may be associated to a single CE or multiple CEs.
CEs may be either dedicated to one single connectivity service or host multiple connectivity services (e.g., CEs with roles of service functions ).
A network provider may bind a single AC to one or multiple peer SAPs (e.g., CE#1 and CE#2 are tagged as peer SAPs for the same AC). For example, and as discussed in , multiple CEs can be attached to a PE over the same attachment circuit. This scenario is typically implemented when the layer 2 infrastructure between the CE and the network is a multipoint service.
A single CE may terminate multiple ACs, which can be associated with the same bearer or distinct bearers.
Customers may request protection schemes in which the ACs associated with their endpoints are terminated by the same PE (e.g., CE#3), distinct PEs (e.g., CE#34), etc. The network provider uses this request to decide where to terminate the AC in the network provider network and also whether to enable specific capabilities (e.g., Virtual Router Redundancy Protocol (VRRP)).

Examples of ACs

Separate AC Provisioning vs. Actual Service Provisioning The procedure to provision a service in a service provider network may depend on the practices adopted by a service provider. This includes the flow put in place for the provisioning of advanced network services and how they are bound to an attachment circuit. For example, a single attachment circuit may be used to host multiple connectivity services. In order to avoid service interference and redundant information in various locations, a service provider may expose an interface to manage ACs network-wide. Customers can then request a bearer or an attachment circuit to be put in place, and then refer to that bearer or AC when requesting services that are bound to the bearer or AC. shows the positioning of the AC service model is the overall service delivery process.

An Example of AC Model Usage In order to ease the mapping between the service model and underlying network models (e.g., L3NM, SAP), the name conventions used in existing network data models are reused as much as possible. For example, "local-address" is used rather than "provider-address" (or similar) to refer to an IP address used in the provider network. This approach is consistent with the automation framework defined in .

Description of the Data Models

The Bearer Service ("ietf-bearer-svc") YANG Module shows the tree for managing the bearers (that is, the properties of the attachment that are below Layer 3). A bearer can be a wireless or wired link. A reference to a bearer is generated by the operator. Such a reference can be used, e.g., in a subsequent service request to create an AC. The anchoring of the AC can also be achieved by indicating (with or without a bearer reference), a peer SAP identifier (e.g., an identifier of a Service Function).

Bearer Service Tree Structure The same customer site (CE, NF, etc.) can terminate one or multiple bearers; each of them uniquely identified by a reference that is assigned by the network provider. These bearers can terminate on the same or distinct network nodes. CEs that terminate multiple bearers are called multi-homed CEs. A bearer request may indicate some hints about the placement constraints ('placement-constraints'). These constraints are used by a provider to determine how/where to terminate a bearer in the network side (e.g., PoP/PE selection). The descriptions of the bearer data nodes are as follows:

'id':: Used to uniquely identify a bearer. This identifier is typically selected by the client when requesting a bearer.
'description':: Includes a textual description of the bearer.
'op-comment':: Includes operational comments that may be useful for managing the bearer (building, level, etc.). No structure is associated with this data node to accommodate all deployments.
'group':: Tags a bearer with one ore more identifiers that are used to group a set of bearers.
'customer-point':: Specifies the customer terminating point for the bearer. A bearer request can indicate a device, a site, a combination thereof, or a custom information when requesting a bearer. All these schemes are supported in the model.
'requested-type':: Specifies the requested bearer type (Ethernet, wireless, etc.).
'bearer-reference':: Returns an internal reference for the service provider to identify the bearer. This reference can be used when requesting services. provides an example about how this reference can be retrieved by a customer.
: Whether the 'bearer-reference' mirrors the content of the 'id' is deployment specific. The module does not assume nor preclude such schemes.
'status':: Used to track the overall status of a given bearer. Both operational and administrative status are maintained together with a timestamp.
: See for more details.

The Attachment Circuit Service ("ietf-ac-svc") YANG Module

Overall Structure The overall tree structure of the AC service module is shown in .

Overall AC Service Tree Structure The full ACaaS tree is available at . The full reusable groupings defined in the ACaaS module are shown in .

The rationale for deciding whether a reusable grouping should be maintained in this document or be moved into the AC common module is as follows:
- Groupings that are reusable among the AC service module, AC network module, other service models, and network models are included in the AC common module.
- Groupings that are reusable only by other service models are maintained in the "ietf-ac-svc" module.

Each AC is identified with a unique name ('../ac/name') within a domain. The mapping between this AC and a local PE that terminates the AC is hidden to the application that makes use of the AC service model. This information is internal to the Network controller. As such, the details about the (node-specific) attachment interfaces are not exposed in this service model. The AC service model uses groupings and types defined in the AC common model . Therefore, the description of these nodes are not reiterated in the following subsections.

Service Profiles

Description The 'specific-provisioning-profiles' container () can be used by a service provider to maintain a set of reusable profiles. The profiles definition are similar to those defined in , including: Quality of Service (QoS), Bidirectional Forwarding Detection (BFD), forwarding, and routing profiles. The exact definition of the profiles is local to each service provider. The model only includes an identifier for these profiles in order to facilitate identifying and binding local policies when building an AC.

Service Profiles As shown in , two profile types can be defined: 'specific-provisioning-profiles' and 'service-provisioning-profiles'. Whether only specific profiles, service profiles, or a combination thereof are used is local to each service provider. The following specific provisioning profiles can be defined:

'encryption-profile-identifier':: Refers to a set of policies related to the encryption setup that can be applied when provisioning an AC.
'qos-profile-identifier':: Refers to a set of policies, such as classification, marking, and actions (e.g., ).
'bfd-profile-identifier':: Refers to a set of Bidirectional Forwarding Detection (BFD) policies that can be invoked when building an AC.
'forwarding-profile-identifier':: Refers to the policies that apply to the forwarding of packets conveyed within an AC. Such policies may consist, for example, of applying Access Control Lists (ACLs).
'routing-profile-identifier':: Refers to a set of routing policies that will be invoked (e.g., BGP policies) when building an AC.

Referencing Service/Specific Profiles All the abovementioned profiles are uniquely identified by the NETCONF/RESTCONF server by an identifier. To ease referencing these profiles by other data models, specific typedefs are defined for each of these profiles. Likewise, an attachment circuit reference typedef is defined when referencing a (global) attachment circuit by its name is required. These typedefs SHOULD be used when other modules need a reference to one of these profiles or attachment circuits.

Attachment Circuits Profiles The 'ac-group-profile' defines reusable parameters for a set of ACes. Each profile is identified by 'name'. Some of the data nodes can be adjusted at the 'ac'. These adjusted values take precedence over the global values. The structure of 'ac-group-profile' is similar to the one used to model each 'ac' ().

AC Placement Contraints The 'placement-constraints' specifies the placement constraints of an AC. For example, this container can be used to request avoiding to connecting two ACes to the same PE. The full set of supported constraints is defined in (see 'placement-diversity', in particular). The structure of 'placement-constraints' is shown in .

Placement Constraints Subtree Structure

Attachment Circuits The structure of 'attachment-circuits' is shown in .

Attachment Circuits Tree Structure The description of the data nodes is as follows:

'customer-name':: Indicates the name of the customer who ordered the AC.
'description':: Includes a textual description of the AC.
'peer-sap-id':: Includes references to the remote endpoints of an attachment circuit .
'ac-group-profile':: Indicates references to one or more profiles that are defined in .
'group':: Lists the groups to which an AC belongs . For example, the 'group-id' is used to associate redundancy or protection constraints of ACes. An example is provided in .
'name':: Associates a name that uniquely identifies an AC within a service provider network.
'l2-connection':: See .
'ip-connection':: See .
'routing':: See .
'oam':: See .
'security':: See .
'service':: See .

Layer 2 Connection Structure The 'l2-connection' container () is used to configure the relevant Layer 2 properties of an AC including: encapsulation details and tunnel terminations. For the encapsulation details, the model supports the definition of the type as well as the Identifiers (e.g., VLAN-IDs) of each of the encapsulation-type defined. For the second case, attributes for pseudowire, Virtual Private LAN Service (VPLS), and Virtual eXtensible Local Area Network (VXLAN) tunnel terminations are included. This structure relies upon the common groupings defined in .

Layer 2 Connection Tree Structure

IP Connection Structure The 'ip-connection' container is used to configure the relevant IP properties of an AC. The model supports the usage of dynamic and static addressing. This structure relies upon the common groupings defined in . Both IPv4 and IPv6 parameters are supported. shows the structure of the IPv4 connection.

Layer 3 Connection Tree Structure (IPv4) shows the structure of the IPv6 connection.

Layer 3 Connection Tree Structure (IPv6)

Routing As shown in the tree depicted in , the 'routing-protocols' container defines the required parameters to enable the desired routing features for an AC. One or more routing protocols can be associated with an AC. Such routing protocols will be then enabled between a PE and the customer terminating points. Each routing instance is uniquely identified by the combination of the 'id' and 'type' to accommodate scenarios where multiple instances of the same routing protocol have to be configured on the same link. In addition to static routing, the module supports BGP, OSPF, IS-IS, and RIP. It also includes a reference to the 'routing-profile-identifier' defined in , so that additional constraints can be applied to a specific instance of each routing protocol.

Routing Tree Structure

Static Routing The static tree structure is shown in .

Static Routing Tree Structure

BGP The BGP tree structure is shown in .

OSPF The OSPF tree structure is shown in .

OSPF Tree Structure

IS-IS The IS-IS tree structure is shown in .

IS-IS Tree Structure

RIP The RIP tree structure is shown in .

RIP Tree Structure 'address-family' indicates whether IPv4, IPv6, or both address families are to be activated. For example, this parameter is used to determine whether RIPv2 , RIP Next Generation (RIPng), or both are to be enabled .

VRRP The model also supports the Virtual Router Redundancy Protocol (VRRP) on an AC ().

VRRP Tree Structure

OAM As shown in the tree depicted in , the 'oam' container defines OAM-related parameters of an AC.

OAM Tree Structure

Security As shown in the tree depicted in , the 'security' container defines a set of AC security parameters.

Security Tree Structure

Service As shown in the tree depicted in , the 'service' container defines the following data nodes:

'mtu':: Specifies the Layer 2 MTU, in bytes, for the AC.
'svc-pe-to-ce-bandwidth':: Indicates the inbound bandwidth of the AC (i.e., download bandwidth from the service provider to the customer site).
'svc-ce-to-pe-bandwidth':: Indicates the outbound bandwidth of the AC (i.e., upload bandwidth from the customer site to the service provider).

Both 'svc-pe-to-ce-bandwidth' and 'svc-ce-to-pe-bandwidth' can be represented using the Committed Information Rate (CIR), the Excess Information Rate (EIR), or the Peak Information Rate (PIR). Both reuse the 'bandwidth-per-type' grouping defined in .

Bandwidth Tree Structure

YANG Modules

The Bearer Service ("ietf-bearer-svc") YANG Module This module uses types defined in and . WG List: Editor: Mohamed Boucadair Author: Richard Roberts Author: Oscar Gonzalez de Dios Author: Samier Barguil Author: Bo Wu "; description "This YANG module defines a generic YANG model for exposing network bearers as a service. Copyright (c) 2023 IETF Trust and the persons identified as authors of the code. 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 Revised BSD License set forth in Section 4.c of the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info). This version of this YANG module is part of RFC xxx; see the RFC itself for full legal notices."; revision 2022-11-30 { description "Initial revision."; reference "RFC xxxx: A YANG Service Data Model for Attachment Circuits"; } // Identities identity identification-type { description "Base identity for identification of bearers."; } identity device-id { base identification-type; description "Identification of bearers based on device.."; } identity site-id { base identification-type; description "Identification of bearers based on site."; } identity site-and-device-id { base identification-type; description "Identification of bearers based on site and device."; } identity custom { base identification-type; description "Identification of bearers based on other custom criteria."; } identity bearer-type { description "Base identity for bearers type."; } identity ethernet { base bearer-type; description "Ethernet."; } identity wireless { base bearer-type; description "Wireless."; } identity network-termination-hint { base vpn-common:placement-diversity; description "A hint about the termination at the network side is provided (e.g., geoproximity)."; } grouping location-information { description "Basic location information"; container location { description "Location of the node."; leaf location-name { type string; description "Provides a location name. This data node can be mapped, e.g., to the 3GPP NRM IOC ManagedElement."; } leaf address { type string; description "Address (number and street) of the device/site."; } leaf postal-code { type string; description "Postal code of the device/site."; } leaf state { type string; description "State of the device/site. This leaf can also be used to describe a region for a country that does not have states."; } leaf city { type string; description "City of the device/site."; } leaf country-code { type string { pattern '[A-Z]{2}'; } description "Country of the device/site. Expressed as ISO ALPHA-2 code."; } } } grouping placement-constraints { description "Constraints related to placement of a bearer."; list constraint { if-feature vpn-common:placement-diversity; key "constraint-type"; description "List of constraints."; leaf constraint-type { type identityref { base vpn-common:placement-diversity; } must "not(derived-from-or-self(current(), " + "'vpn-common:bearer-diverse') or " + "derived-from-or-self(current(), " + "'vpn-common:same-bearer'))" { error-message "Only bearer-specific diversity" + "constraints must be provided."; } description "Diversity constraint type for bearers."; } container target { description "The constraint will apply against this list of groups."; choice target-flavor { description "Choice for the group definition."; case id { list group { key "group-id"; description "List of groups."; leaf group-id { type string; description "The constraint will apply against this particular group ID."; } } } case all-bearers { leaf all-other-bearers { type empty; description "The constraint will apply against all other bearers of a site."; } } case all-groups { leaf all-other-groups { type empty; description "The constraint will apply against all other groups managed by the customer."; } } } } } } container bearers { description "Main container for the bearers."; container placement-constraints { description "Diversity constraint type."; uses placement-constraints; } list bearer { key "id"; description "Maintains a list of bearers."; leaf id { type string; description "An identifier of the bearer."; } leaf description { type string; description "A description of this bearer."; } uses vpn-common:vpn-components-group; leaf op-comment { type string; description "Includes comments that can be shared with operational teams and which may be useful for the activation of a bearer. This may include, for example, information about the building, level, etc."; } container customer-point { description "Base container to link the Bearer existence"; leaf identified-by { type identityref { base identification-type; } description "Attribute used to identify the bearer"; } container device { when "derived-from-or-self(../identified-by, " + "'device-id') or derived-from-or-self(../identified-by, " + "'site-and-device-id')" { description "Only applicable if identified-by is device."; } description "Bearer is linked to device."; leaf device-id { type string; description "Identifier for the device where that bearer belongs."; } uses location-information; } container site { when "derived-from-or-self(../identified-by, " + "'site-id') or derived-from-or-self(../identified-by, " + "'site-and-device-id')" { description "Only applicable if identified-by is site."; } description "Bearer is linked to a site."; leaf site-id { type string; description "Identifier for the site or sites where that bearer belongs."; } uses location-information; } leaf custom-id { when "derived-from-or-self(../identified-by, " + "'custom')" { description "Only enabled id identified-by is custom."; } type string; description "The semantic of this identifier is shared between the customer/provider using out-of-band means."; } } leaf requested-type { type identityref { base bearer-type; } description "Type of the requested bearer (e.g., Ethernet or wireless)"; } leaf bearer-reference { if-feature "vpn-common:bearer-reference"; type string; config false; description "This is an internal reference for the service provider to identify the bearers."; } leaf-list ac-refs { type ac-svc:attachment-circuit-reference; config false; description "Specifies the set of ACes that are bound to the bearer."; } uses ac-common:op-instructions; uses vpn-common:service-status; } } } ]]>

The AC Service ("ietf-ac-svc") YANG Module This module uses types defined in , , , and . WG List: Editor: Mohamed Boucadair Author: Richard Roberts Author: Oscar Gonzalez de Dios Author: Samier Barguil Author: Bo Wu "; description "This YANG module defines a YANG model for exposing attachment circuits as a service (ACaaS). Copyright (c) 2023 IETF Trust and the persons identified as authors of the code. 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 Revised BSD License set forth in Section 4.c of the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info). This version of this YANG module is part of RFC XXXX; see the RFC itself for full legal notices."; revision 2022-11-30 { description "Initial revision."; reference "RFC XXXX: YANG Service Data Models for Attachment Circuits"; } /* A set of typedefs to ease referencing cross-modules */ typedef attachment-circuit-reference { type leafref { path "/ac-svc:attachment-circuits/ac-svc:ac/ac-svc:name"; } description "Defines a reference to an attachment circuit that can be used by other modules."; } typedef ac-group-reference { type leafref { path "/ac-svc:attachment-circuits/ac-group-profile/name"; } description "Defines a reference to an attachment circuit profile."; } typedef encryption-profile-reference { type leafref { path "/ac-svc:specific-provisioning-profiles/ac-svc:valid-provider-identifiers" + "/ac-svc:encryption-profile-identifier/ac-svc:id"; } description "Defines a type to an encryption profile for referencing purposes."; } typedef qos-profile-reference { type leafref { path "/ac-svc:specific-provisioning-profiles/ac-svc:valid-provider-identifiers" + "/ac-svc:qos-profile-identifier/ac-svc:id"; } description "Defines a type to a QoS profile for referencing purposes."; } typedef bfd-profile-reference { type leafref { path "/ac-svc:specific-provisioning-profiles/ac-svc:valid-provider-identifiers" + "/ac-svc:bfd-profile-identifier/ac-svc:id"; } description "Defines a type to a BFD profile for referencing purposes."; } typedef forwarding-profile-reference { type leafref { path "/ac-svc:specific-provisioning-profiles/ac-svc:valid-provider-identifiers" + "/ac-svc:forwarding-profile-identifier/ac-svc:id"; } description "Defines a type to a forwarding profile for referencing purposes."; } typedef routing-profile-reference { type leafref { path "/ac-svc:specific-provisioning-profiles/ac-svc:valid-provider-identifiers" + "/ac-svc:routing-profile-identifier/ac-svc:id"; } description "Defines a type to a routing profile for referencing purposes."; } typedef service-profile-reference { type leafref { path "/ac-svc:service-provisioning-profiles/ac-svc:service-profile-identifier" + "/ac-svc:id"; } description "Defines a type to a service profile for referencing purposes."; } /******************** Reusable groupings ********************/ // Basic Layer 2 connection grouping l2-connection-basic { description "Defines Layer 2 protocols and parameters that can be factorized when provisioning Layer 2 connectivity among multiple ACs."; container encapsulation { description "Container for Layer 2 encapsulation."; leaf type { type identityref { base vpn-common:encapsulation-type; } description "Encapsulation type."; } container dot1q { when "derived-from-or-self(../type, 'vpn-common:dot1q')" { description "Only applies when the type of the tagged interface is 'dot1q'."; } description "Tagged interface."; uses ac-common:dot1q; } container qinq { when "derived-from-or-self(../type, 'vpn-common:qinq')" { description "Only applies when the type of the tagged interface is 'qinq'."; } description "Includes QinQ parameters."; uses ac-common:qinq; } } } // Full Layer 2 connection grouping l2-connection { description "Defines Layer 2 protocols and parameters that are used to enable AC connectivity."; container encapsulation { description "Container for Layer 2 encapsulation."; leaf type { type identityref { base vpn-common:encapsulation-type; } description "Encapsulation type."; } container dot1q { when "derived-from-or-self(../type, 'vpn-common:dot1q')" { description "Only applies when the type of the tagged interface is 'dot1q'."; } description "Tagged interface."; uses ac-common:dot1q; } container priority-tagged { when "derived-from-or-self(../type, " + "'vpn-common:priority-tagged')" { description "Only applies when the type of the tagged interface is 'priority-tagged'."; } description "Priority-tagged interface."; uses ac-common:priority-tagged; } container qinq { when "derived-from-or-self(../type, 'vpn-common:qinq')" { description "Only applies when the type of the tagged interface is 'qinq'."; } description "Includes QinQ parameters."; uses ac-common:qinq; } } choice l2-service { description "The Layer 2 connectivity service can be provided by indicating a pointer to an L2VPN or by specifying a Layer 2 tunnel service."; container l2-tunnel-service { description "Defines a Layer 2 tunnel termination. It is only applicable when a tunnel is required."; uses ac-common:l2-tunnel-service; } case l2vpn { leaf l2vpn-id { type vpn-common:vpn-id; description "Indicates the L2VPN service associated with an Integrated Routing and Bridging (IRB) interface."; } } } leaf bearer-reference { if-feature "vpn-common:bearer-reference"; type string; description "This is an internal reference for the service provider to identify the bearer associated with this AC."; } } // Basic IP connection grouping ip-connection-basic { description "Defines basic IP connection parameters."; container ipv4 { if-feature "vpn-common:ipv4"; description "IPv4-specific parameters."; uses ac-common:ipv4-connection-basic; } container ipv6 { if-feature "vpn-common:ipv6"; description "IPv6-specific parameters."; uses ac-common:ipv6-connection-basic; } } // Full IP connection grouping ip-connection { description "Defines IP connection parameters."; container ipv4 { if-feature "vpn-common:ipv4"; description "IPv4-specific parameters."; uses ac-common:ipv4-connection; } container ipv6 { if-feature "vpn-common:ipv6"; description "IPv6-specific parameters."; uses ac-common:ipv6-connection; } } // Routing protocol list grouping routing-protocol-list { description "List of routing protocols used on the AC."; leaf type { type identityref { base vpn-common:routing-protocol-type; } description "Type of routing protocol."; } list routing-profiles { key "id"; description "Routing profiles."; leaf id { type routing-profile-reference; description "Reference to the routing profile to be used."; } leaf type { type identityref { base vpn-common:ie-type; } description "Import, export, or both."; } } } // BGP Service grouping bgp-svc { description "Configuration specific to BGP."; container peer-groups { description "Configuration for BGP peer-groups"; list peer-group { key "name"; description "List of BGP peer-groups configured on the local system - uniquely identified by peer-group name"; uses ac-common:bgp-peer-group-with-name; leaf local-address { type inet:ip-address; description "The local IP address that will be used to establish the BGP session."; } uses ac-common:bgp-authentication; } } list neighbor { key "id"; description "List of BGP neighbors."; leaf id { type string; description "A neighbor identifier."; } leaf remote-address { type inet:ip-address; description "The remote IP address of this entry's BGP peer. If this leaf is not present, this means that the primary customer IP address is used as remote IP address."; } leaf local-address { type inet:ip-address; description "The local IP address that will be used to establish the BGP session."; } leaf peer-group { type leafref { path "../../peer-groups/peer-group/name"; } description "The peer-group with which this neighbor is associated."; } uses ac-common:bgp-peer-group-without-name; uses ac-common:bgp-authentication; uses vpn-common:service-status; } } // OSPF Service grouping ospf-svc { description "Service configuration specific to OSPF."; uses ac-common:ospf-basic; uses ac-common:ospf-authentication; uses vpn-common:service-status; } // IS-IS Service grouping isis-svc { description "Service configuration specific to IS-IS."; uses ac-common:isis-basic; uses ac-common:isis-authentication; uses vpn-common:service-status; } // RIP Service grouping rip-svc { description "Service configuration specific to RIP routing."; leaf address-family { type identityref { base vpn-common:address-family; } description "Indicates whether IPv4, IPv6, or both address families are to be activated."; } uses ac-common:rip-authentication; uses vpn-common:service-status; } // VRRP Service grouping vrrp-svc { description "Service configuration specific to VRRP."; reference "RFC 5798: Virtual Router Redundancy Protocol (VRRP) Version 3 for IPv4 and IPv6"; leaf address-family { type identityref { base vpn-common:address-family; } description "Indicates whether IPv4, IPv6, or both address families are to be enabled."; } uses vpn-common:service-status; } // Basic routing parameters grouping routing-basic { description "Defines basic parameters for routing protocols."; list routing-protocol { key "id"; description "List of routing protocols used on the AC."; leaf id { type string; description "Unique identifier for the routing protocol."; } uses routing-protocol-list; container bgp { when "derived-from-or-self(../type, 'vpn-common:bgp-routing')" { description "Only applies when the protocol is BGP."; } description "Configuration specific to BGP."; container peer-groups { description "Configuration for BGP peer-groups"; list peer-group { key "name"; description "List of BGP peer-groups configured on the local system - uniquely identified by peer-group name"; uses ac-common:bgp-peer-group-with-name; } } } container ospf { when "derived-from-or-self(../type, " + "'vpn-common:ospf-routing')" { description "Only applies when the protocol is OSPF."; } description "Configuration specific to OSPF."; uses ac-common:ospf-basic; } container isis { when "derived-from-or-self(../type, " + "'vpn-common:isis-routing')" { description "Only applies when the protocol is IS-IS."; } description "Configuration specific to IS-IS."; uses ac-common:isis-basic; } container rip { when "derived-from-or-self(../type, " + "'vpn-common:rip-routing')" { description "Only applies when the protocol is RIP. For IPv4, the model assumes that RIP version 2 is used."; } description "Configuration specific to RIP routing."; leaf address-family { type identityref { base vpn-common:address-family; } description "Indicates whether IPv4, IPv6, or both address families are to be activated."; } } container vrrp { when "derived-from-or-self(../type, " + "'vpn-common:vrrp-routing')" { description "Only applies when the protocol is the Virtual Router Redundancy Protocol (VRRP)."; } description "Configuration specific to VRRP."; leaf address-family { type identityref { base vpn-common:address-family; } description "Indicates whether IPv4, IPv6, or both address families are to be enabled."; } } } } // Full routing parameters grouping routing { description "Defines routing protocols."; list routing-protocol { key "id"; description "List of routing protocols used on the AC."; leaf id { type string; description "Unique identifier for the routing protocol."; } uses routing-protocol-list; container static { when "derived-from-or-self(../type, " + "'vpn-common:static-routing')" { description "Only applies when the protocol is static routing protocol."; } description "Configuration specific to static routing."; container cascaded-lan-prefixes { description "LAN prefixes from the customer."; uses ac-common:ipv4-static-rtg; uses ac-common:ipv6-static-rtg; } } container bgp { when "derived-from-or-self(../type, " + "'vpn-common:bgp-routing')" { description "Only applies when the protocol is BGP."; } description "Configuration specific to BGP."; uses bgp-svc { refine "peer-groups/peer-group/local-address" { config false; } refine "neighbor/local-address" { config false; } } } container ospf { when "derived-from-or-self(../type, " + "'vpn-common:ospf-routing')" { description "Only applies when the protocol is OSPF."; } description "Configuration specific to OSPF."; uses ospf-svc; } container isis { when "derived-from-or-self(../type, " + "'vpn-common:isis-routing')" { description "Only applies when the protocol is IS-IS."; } description "Configuration specific to IS-IS."; uses isis-svc; } container rip { when "derived-from-or-self(../type, " + "'vpn-common:rip-routing')" { description "Only applies when the protocol is RIP. For IPv4, the model assumes that RIP version 2 is used."; } description "Configuration specific to RIP routing."; uses rip-svc; } container vrrp { when "derived-from-or-self(../type, " + "'vpn-common:vrrp-routing')" { description "Only applies when the protocol is the Virtual Router Redundancy Protocol (VRRP)."; } description "Configuration specific to VRRP."; uses vrrp-svc; } } } // Encryption choice grouping encryption-choice { description "Container for the encryption profile."; choice profile { description "Choice for the encryption profile."; case provider-profile { leaf provider-profile { type encryption-profile-reference; description "Reference to a provider encryption profile."; } } case customer-profile { leaf customer-key-chain { type key-chain:key-chain-ref; description "Customer-supplied key chain."; } } } } // Basic security parameters grouping ac-security-basic { description "AC-specific security parameters."; container encryption { if-feature "vpn-common:encryption"; description "Container for AC security encryption."; leaf enabled { type boolean; description "If set to 'true', traffic encryption on the connection is required. Otherwise, it is disabled."; } leaf layer { when "../enabled = 'true'" { description "Included only when encryption is enabled."; } type enumeration { enum layer2 { description "Encryption occurs at Layer 2."; } enum layer3 { description "Encryption occurs at Layer 3. For example, IPsec may be used when a customer requests Layer 3 encryption."; } } description "Indicates the layer on which encryption is applied."; } } container encryption-profile { when "../encryption/enabled = 'true'" { description "Indicates the layer on which encryption is enabled."; } description "Container for the encryption profile."; uses encryption-choice; } } // Bandwith grouping bandwidth { description "Container for bandwidth."; container svc-pe-to-ce-bandwidth { if-feature "vpn-common:inbound-bw"; description "From the customer site's perspective, the inbound bandwidth of the AC or download bandwidth from the service provider to the site."; uses ac-common:bandwidth-per-type; } container svc-ce-to-pe-bandwidth { if-feature "vpn-common:outbound-bw"; description "From the customer site's perspective, the outbound bandwidth of the AC or upload bandwidth from the CE to the PE."; uses ac-common:bandwidth-per-type; } } // Basic AC parameter grouping ac-basic { description "Grouping for basic parameters for an attachment circuit."; leaf id { type string; description "An identifier of the AC."; } container l2-connection { description "Defines Layer 2 protocols and parameters that are required to enable AC connectivity."; uses l2-connection-basic; } container ip-connection { description "Defines IP connection parameters."; uses ip-connection-basic; } container routing-protocols { description "Defines routing protocols."; uses routing-basic; } container oam { description "Defines the Operations, Administration, and Maintenance (OAM) mechanisms used."; container bfd { if-feature "vpn-common:bfd"; description "Container for BFD."; uses ac-common:bfd; } } container security { description "AC-specific security parameters."; uses ac-security-basic; } container service { description "AC-specific bandwith parameters."; leaf mtu { type uint32; units "bytes"; description "Layer 2 MTU."; } uses bandwidth; } } // Full AC parameters grouping ac { description "Grouping for an attachment circuit."; leaf name { type string; description "A name of the AC. Data models that need to reference an attachment circuits should use attachment-circuit-reference."; } leaf-list service-profile { type service-profile-reference; description "A reference to a service profile."; } container l2-connection { description "Defines Layer 2 protocols and parameters that are required to enable AC connectivity."; uses l2-connection; } container ip-connection { description "Defines IP connection parameters."; uses ip-connection; } container routing-protocols { description "Defines routing protocols."; uses routing; } container oam { description "Defines the OAM mechanisms used."; container bfd { if-feature "vpn-common:bfd"; description "Container for BFD."; uses ac-common:bfd; uses vpn-common:service-status; } } container security { description "AC-specific security parameters."; uses ac-security-basic; } container service { description "AC-specific bandwith parameters."; uses bandwidth; } } /******************** Main AC containers ********************/ container specific-provisioning-profiles { description "Contains a set of valid profiles to reference for an AC."; uses ac-common:ac-profile-cfg; } container service-provisioning-profiles { description "Contains a set of valid profiles to reference for an AC."; list service-profile-identifier { key "id"; description "List of generic service profile identifiers."; leaf id { type string; description "Identification of the service profile to be used. The profile only has significance within the service provider's administrative domain."; } } nacm:default-deny-write; } container attachment-circuits { description "Main container for the attachment circuits."; list ac-group-profile { key "name"; description "Maintains a list of profiles that are shared among a set of ACs."; uses ac; } container placement-constraints { description "Diversity constraint type."; uses vpn-common:placement-constraints; } list ac { key "name"; description "Global provisioning of attachment circuits."; leaf customer-name { type string; description "Indicates the name of the customer that requested this AC."; } leaf description { type string; description "Associates a description with an AC."; } uses ac-common:op-instructions; leaf-list peer-sap-id { type string; description "One or more peer SAPs can be indicated."; } leaf-list ac-group-profile { type ac-group-reference; description "A reference to an AC profile."; } list group { key "group-id"; description "List of group-ids."; leaf group-id { type string; description "Indicates the group-id to which the network access belongs."; } leaf precedence { type identityref { base ac-common:precedence-type; } description "Defines redundancy of an AC."; } } uses ac; } } } ]]>

Security Considerations The YANG modules specified in this document define schema for data that is designed to be accessed via network management protocols such as NETCONF or RESTCONF . The lowest NETCONF layer is the secure transport layer, and the mandatory-to-implement secure transport is Secure Shell (SSH) . The lowest RESTCONF layer is HTTPS, and the mandatory-to-implement secure transport is TLS . The Network Configuration Access Control Model (NACM) provides the means to restrict access for particular NETCONF or RESTCONF users to a preconfigured subset of all available NETCONF or RESTCONF protocol operations and content. There are a number of data nodes defined in these YANG modules that are writable/creatable/deletable (i.e., config true, which is the default). These data nodes may be considered sensitive or vulnerable in some network environments. Write operations (e.g., edit-config) and delete operations to these data nodes without proper protection or authentication can have a negative effect on network operations. These are the subtrees and data nodes and their sensitivity/ vulnerability in the "ietf-ac-svc" module:

Some of the readable data nodes in these YANG module may be considered sensitive or vulnerable in some network environments. It is thus important to control read access (e.g., via get, get-config, or notification) to these data nodes. These are the subtrees and data nodes and their sensitivity/vulnerability in the "ietf-ac-svc" module:

'customer-name', 'l2-connection', and 'ip-connection':: An attacker can retrieve privacy-related information, which can be used to track a customer. Disclosing such information may be considered a violation of the customer-provider trust relationship.
'keying-material':: An attacker can retrieve the cryptographic keys protecting the underlying connectivity services (routing, in particular). These keys could be used to inject spoofed routing advertisements.

Several data nodes ('bgp', 'ospf', 'isis', and 'rip') rely upon for authentication purposes. As such, the AC service module inherits the security considerations discussed in Section 5 of . Also, these data nodes support supplying explicit keys as strings in ASCII format. The use of keys in hexadecimal string format would afford greater key entropy with the same number of key- string octets. However, such a format is not included in this version of the AC service model, because it is not supported by the underlying device modules (e.g., ).

IANA Considerations IANA is requested to register the following URIs in the "ns" subregistry within the "IETF XML Registry" : IANA is requested to register the following YANG modules in the "YANG Module Names" subregistry within the "YANG Parameters" registry.

References Normative References BGP/MPLS IP Virtual Private Networks (VPNs) This document describes a method by which a Service Provider may use an IP backbone to provide IP Virtual Private Networks (VPNs) for its customers. This method uses a "peer model", in which the customers' edge routers (CE routers) send their routes to the Service Provider's edge routers (PE routers); there is no "overlay" visible to the customer's routing algorithm, and CE routers at different sites do not peer with each other. Data packets are tunneled through the backbone, so that the core routers do not need to know the VPN routes. [STANDARDS-TRACK] Network Management Datastore Architecture (NMDA) Datastores are a fundamental concept binding the data models written in the YANG data modeling language to network management protocols such as the Network Configuration Protocol (NETCONF) and RESTCONF. This document defines an architectural framework for datastores based on the experience gained with the initial simpler model, addressing requirements that were not well supported in the initial model. This document updates RFC 7950. Key words for use in RFCs to Indicate Requirement Levels In many standards track documents several words are used to signify the requirements in the specification. These words are often capitalized. This document defines these words as they should be interpreted in IETF documents. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements. Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words RFC 2119 specifies common key words that may be used in protocol specifications. This document aims to reduce the ambiguity by clarifying that only UPPERCASE usage of the key words have the defined special meanings. A Common YANG Data Model for Layer 2 and Layer 3 VPNs This document defines a common YANG module that is meant to be reused by various VPN-related modules such as Layer 3 VPN and Layer 2 VPN network models. A Common YANG Data Model for Attachment Circuits Orange Juniper Telefonica Nokia Huawei Technologies The document specifies a common Attachment Circuits (ACs) YANG module, which is designed with the intent to be reusable by other models. For example, this common model can be reused by service models to expose ACs as a service, service models that require binding a service to a set of ACs, network and device models to provision ACs, etc. Bidirectional Forwarding Detection (BFD) This document describes a protocol intended to detect faults in the bidirectional path between two forwarding engines, including interfaces, data link(s), and to the extent possible the forwarding engines themselves, with potentially very low latency. It operates independently of media, data protocols, and routing protocols. [STANDARDS-TRACK] YANG Data Model for Key Chains This document describes the key chain YANG data model. Key chains are commonly used for routing protocol authentication and other applications requiring symmetric keys. A key chain is a list containing one or more elements containing a Key ID, key string, send/accept lifetimes, and the associated authentication or encryption algorithm. By properly overlapping the send and accept lifetimes of multiple key chain elements, key strings and algorithms may be gracefully updated. By representing them in a YANG data model, key distribution can be automated. Common YANG Data Types This document introduces a collection of common data types to be used with the YANG data modeling language. This document obsoletes RFC 6021. Network Configuration Protocol (NETCONF) The Network Configuration Protocol (NETCONF) defined in this document provides mechanisms to install, manipulate, and delete the configuration of network devices. It uses an Extensible Markup Language (XML)-based data encoding for the configuration data as well as the protocol messages. The NETCONF protocol operations are realized as remote procedure calls (RPCs). This document obsoletes RFC 4741. [STANDARDS-TRACK] RESTCONF Protocol This document describes an HTTP-based protocol that provides a programmatic interface for accessing data defined in YANG, using the datastore concepts defined in the Network Configuration Protocol (NETCONF). Using the NETCONF Protocol over Secure Shell (SSH) This document describes a method for invoking and running the Network Configuration Protocol (NETCONF) within a Secure Shell (SSH) session as an SSH subsystem. This document obsoletes RFC 4742. [STANDARDS-TRACK] The Transport Layer Security (TLS) Protocol Version 1.3 This document specifies version 1.3 of the Transport Layer Security (TLS) protocol. TLS allows client/server applications to communicate over the Internet in a way that is designed to prevent eavesdropping, tampering, and message forgery. This document updates RFCs 5705 and 6066, and obsoletes RFCs 5077, 5246, and 6961. This document also specifies new requirements for TLS 1.2 implementations. Network Configuration Access Control Model The standardization of network configuration interfaces for use with the Network Configuration Protocol (NETCONF) or the RESTCONF protocol requires a structured and secure operating environment that promotes human usability and multi-vendor interoperability. There is a need for standard mechanisms to restrict NETCONF or RESTCONF protocol access for particular users to a preconfigured subset of all available NETCONF or RESTCONF protocol operations and content. This document defines such an access control model. This document obsoletes RFC 6536. The IETF XML Registry This document describes an IANA maintained registry for IETF standards which use Extensible Markup Language (XML) related items such as Namespaces, Document Type Declarations (DTDs), Schemas, and Resource Description Framework (RDF) Schemas. YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF) YANG is a data modeling language used to model configuration and state data manipulated by the Network Configuration Protocol (NETCONF), NETCONF remote procedure calls, and NETCONF notifications. [STANDARDS-TRACK] Informative References Full Service Attachment Circuit Tree Structure Reusable Groupings in Service Attachment Circuits Service Function Chaining (SFC) Architecture This document describes an architecture for the specification, creation, and ongoing maintenance of Service Function Chains (SFCs) in a network. It includes architectural concepts, principles, and components used in the construction of composite services through deployment of SFCs, with a focus on those to be standardized in the IETF. This document does not propose solutions, protocols, or extensions to existing protocols. A YANG Network Data Model for Service Attachment Points (SAPs) This document defines a YANG data model for representing an abstract view of the provider network topology that contains the points from which its services can be attached (e.g., basic connectivity, VPN, network slices). Also, the model can be used to retrieve the points where the services are actually being delivered to customers (including peer networks). This document augments the 'ietf-network' data model defined in RFC 8345 by adding the concept of Service Attachment Points (SAPs). The SAPs are the network reference points to which network services, such as Layer 3 Virtual Private Network (L3VPN) or Layer 2 Virtual Private Network (L2VPN), can be attached. One or multiple services can be bound to the same SAP. Both User-to-Network Interface (UNI) and Network-to-Network Interface (NNI) are supported in the SAP data model. IPv4 Address Blocks Reserved for Documentation Three IPv4 unicast address blocks are reserved for use in examples in specifications and other documents. This document describes the use of these blocks. This document is not an Internet Standards Track specification; it is published for informational purposes. IPv6 Address Prefix Reserved for Documentation To reduce the likelihood of conflict and confusion when relating documented examples to deployed systems, an IPv6 unicast address prefix is reserved for use in examples in RFCs, books, documentation, and the like. Since site-local and link-local unicast addresses have special meaning in IPv6, these addresses cannot be used in many example situations. The document describes the use of the IPv6 address prefix 2001:DB8::/32 as a reserved prefix for use in documentation. This memo provides information for the Internet community. Autonomous System (AS) Number Reservation for Documentation Use To reduce the likelihood of conflict and confusion when relating documented examples to deployed systems, two blocks of Autonomous System numbers (ASNs) are reserved for use in examples in RFCs, books, documentation, and the like. This document describes the reservation of two blocks of ASNs as reserved numbers for use in documentation. This memo provides information for the Internet community. A Framework for Automating Service and Network Management with YANG Data models provide a programmatic approach to represent services and networks. Concretely, they can be used to derive configuration information for network and service components, and state information that will be monitored and tracked. Data models can be used during the service and network management life cycle (e.g., service instantiation, service provisioning, service optimization, service monitoring, service diagnosing, and service assurance). Data models are also instrumental in the automation of network management, and they can provide closed-loop control for adaptive and deterministic service creation, delivery, and maintenance. This document describes a framework for service and network management automation that takes advantage of YANG modeling technologies. This framework is drawn from a network operator perspective irrespective of the origin of a data model; thus, it can accommodate YANG modules that are developed outside the IETF. A Network YANG Data Model for Attachment Circuits Orange Juniper Telefonica Nokia Huawei Technologies This document specifies a network model for attachment circuits. The model can be used for the provisioning of attachment circuits prior or during service provisioning (e.g., Network Slice Service). A companion service model is specified in [I-D.boro-opsawg-teas-attachment-circuit]. The module augments the Service Attachment Point (SAP) model with the detailed information for the provisioning of attachment circuits in Provider Edges (PEs). A YANG Data Model for Routing Management (NMDA Version) This document specifies three YANG modules and one submodule. Together, they form the core routing data model that serves as a framework for configuring and managing a routing subsystem. It is expected that these modules will be augmented by additional YANG modules defining data models for control-plane protocols, route filters, and other functions. The core routing data model provides common building blocks for such extensions -- routes, Routing Information Bases (RIBs), and control-plane protocols. The YANG modules in this document conform to the Network Management Datastore Architecture (NMDA). This document obsoletes RFC 8022. YANG Model for Border Gateway Protocol (BGP-4) Kloud Services Arrcus Huawei Juniper Networks This document defines a YANG data model for configuring and managing BGP, including protocol, policy, and operational aspects, such as RIB, based on data center, carrier, and content provider operational requirements. A YANG Data Model for Layer 2 Virtual Private Network (L2VPN) Service Delivery This document defines a YANG data model that can be used to configure a Layer 2 provider-provisioned VPN service. It is up to a management system to take this as an input and generate specific configuration models to configure the different network elements to deliver the service. How this configuration of network elements is done is out of scope for this document. The YANG data model defined in this document includes support for point-to-point Virtual Private Wire Services (VPWSs) and multipoint Virtual Private LAN Services (VPLSs) that use Pseudowires signaled using the Label Distribution Protocol (LDP) and the Border Gateway Protocol (BGP) as described in RFCs 4761 and 6624. The YANG data model defined in this document conforms to the Network Management Datastore Architecture defined in RFC 8342. YANG Data Model for L3VPN Service Delivery This document defines a YANG data model that can be used for communication between customers and network operators and to deliver a Layer 3 provider-provisioned VPN service. This document is limited to BGP PE-based VPNs as described in RFCs 4026, 4110, and 4364. This model is intended to be instantiated at the management system to deliver the overall service. It is not a configuration model to be used directly on network elements. This model provides an abstracted view of the Layer 3 IP VPN service configuration components. It will be up to the management system to take this model as input and use specific configuration models to configure the different network elements to deliver the service. How the configuration of network elements is done is out of scope for this document. This document obsoletes RFC 8049; it replaces the unimplementable module in that RFC with a new module with the same name that is not backward compatible. The changes are a series of small fixes to the YANG module and some clarifications to the text. YANG Tree Diagrams This document captures the current syntax used in YANG module tree diagrams. The purpose of this document is to provide a single location for this definition. This syntax may be updated from time to time based on the evolution of the YANG language. Policy Quality of Service (QoS) Information Model This document presents an object-oriented information model for representing Quality of Service (QoS) network management policies. This document is based on the IETF Policy Core Information Model and its extensions. It defines an information model for QoS enforcement for differentiated and integrated services using policy. It is important to note that this document defines an information model, which by definition is independent of any particular data storage mechanism and access protocol. A YANG Network Data Model for Layer 3 VPNs As a complement to the Layer 3 Virtual Private Network Service Model (L3SM), which is used for communication between customers and service providers, this document defines an L3VPN Network Model (L3NM) that can be used for the provisioning of Layer 3 Virtual Private Network (L3VPN) services within a service provider network. The model provides a network-centric view of L3VPN services. The L3NM is meant to be used by a network controller to derive the configuration information that will be sent to relevant network devices. The model can also facilitate communication between a service orchestrator and a network controller/orchestrator. The TCP Authentication Option This document specifies the TCP Authentication Option (TCP-AO), which obsoletes the TCP MD5 Signature option of RFC 2385 (TCP MD5). TCP-AO specifies the use of stronger Message Authentication Codes (MACs), protects against replays even for long-lived TCP connections, and provides more details on the association of security with TCP connections than TCP MD5. TCP-AO is compatible with either a static Master Key Tuple (MKT) configuration or an external, out-of-band MKT management mechanism; in either case, TCP-AO also protects connections when using the same MKT across repeated instances of a connection, using traffic keys derived from the MKT, and coordinates MKT changes between endpoints. The result is intended to support current infrastructure uses of TCP MD5, such as to protect long-lived connections (as used, e.g., in BGP and LDP), and to support a larger set of MACs with minimal other system and operational changes. TCP-AO uses a different option identifier than TCP MD5, even though TCP-AO and TCP MD5 are never permitted to be used simultaneously. TCP-AO supports IPv6, and is fully compatible with the proposed requirements for the replacement of TCP MD5. [STANDARDS-TRACK] RIP Version 2 This document specifies an extension of the Routing Information Protocol (RIP) to expand the amount of useful information carried in RIP messages and to add a measure of security. [STANDARDS-TRACK] RIPng for IPv6 This document specifies a routing protocol for an IPv6 internet. It is based on protocols and algorithms currently in wide use in the IPv4 Internet [STANDARDS-TRACK] Virtual Router Redundancy Protocol (VRRP) Version 3 for IPv4 and IPv6 This memo defines the Virtual Router Redundancy Protocol (VRRP) for IPv4 and IPv6. It is version three (3) of the protocol, and it is based on VRRP (version 2) for IPv4 that is defined in RFC 3768 and in "Virtual Router Redundancy Protocol for IPv6". VRRP specifies an election protocol that dynamically assigns responsibility for a virtual router to one of the VRRP routers on a LAN. The VRRP router controlling the IPv4 or IPv6 address(es) associated with a virtual router is called the Master, and it forwards packets sent to these IPv4 or IPv6 addresses. VRRP Master routers are configured with virtual IPv4 or IPv6 addresses, and VRRP Backup routers infer the address family of the virtual addresses being carried based on the transport protocol. Within a VRRP router, the virtual routers in each of the IPv4 and IPv6 address families are a domain unto themselves and do not overlap. The election process provides dynamic failover in the forwarding responsibility should the Master become unavailable. For IPv4, the advantage gained from using VRRP is a higher-availability default path without requiring configuration of dynamic routing or router discovery protocols on every end-host. For IPv6, the advantage gained from using VRRP for IPv6 is a quicker switchover to Backup routers than can be obtained with standard IPv6 Neighbor Discovery mechanisms. [STANDARDS-TRACK] A YANG Data Model for the Routing Information Protocol (RIP) This document describes a data model for the management of the Routing Information Protocol (RIP). Both RIP version 2 and RIPng are covered. The data model includes definitions for configuration, operational state, and Remote Procedure Calls (RPCs). The YANG data model in this document conforms to the Network Management Datastore Architecture (NMDA). A YANG Data Model for the IETF Network Slice Service Huawei Technologies Huawei Technologies Ciena Cisco Systems, Inc China Mobile Cisco Systems, Inc This document defines a YANG data model for the IETF Network Slice Service. The model can be used in the IETF Network Slice Service interface between a customer and a provider that offers IETF Network Slices. Updated Security Considerations for the MD5 Message-Digest and the HMAC-MD5 Algorithms This document updates the security considerations for the MD5 message digest algorithm. It also updates the security considerations for HMAC-MD5. This document is not an Internet Standards Track specification; it is published for informational purposes. Analysis of BGP, LDP, PCEP, and MSDP Issues According to the Keying and Authentication for Routing Protocols (KARP) Design Guide This document analyzes TCP-based routing protocols, the Border Gateway Protocol (BGP), the Label Distribution Protocol (LDP), the Path Computation Element Communication Protocol (PCEP), and the Multicast Source Distribution Protocol (MSDP), according to guidelines set forth in Section 4.2 of "Keying and Authentication for Routing Protocols Design Guidelines", RFC 6518.

Examples This section includes a non-exhaustive list of examples to illustrate the use of the service models defined in this document.

Create A New Bearer An example of a request message body to create a bearer is shown in .

Example of a Message Body to Create A New Bearer A bearer-reference is then generated by the controller for this bearer. shows the example of a response message body that is sent by the controller to reply to a GET request:

Example of a Response Message Body with the Bearer Reference

Create An AC over An Existing Bearer An example of a request message body to create a simple AC over an existing bearer is shown in . The bearer reference is assumed to be known to both the customer and the network provider. Such a reference can be retrieved, e.g., following the example described in or using other means (including, exchanged out-of-band or via proprietary APIs).

Example of a Message Body to Request an AC over an Existing Bearer shows the message body of a response received from the controller and which indicates the "cvlan-id" that was assigned for the requested AC.

Example of a Message Body of a Response to Assign a CVLAN ID

Create An AC for a Known Peer SAP An example of a request to create a simple AC, when the peer SAP is known, is shown in . In this example, the peer SAP identifier points to an identifier of a service function. The (topological) location of that service function is assumed to be known to the network controller. For example, this can be determined as part of an on-demand procedure to instantiate a service function in a cloud. That instantiated service function can be granted a connectivity service via the provider network.

Example of a Message Body to Request an AC with a Peer SAP

One CE, Two ACs Let’s consider the example of an eNodeB (CE) that is directly connected to the access routers of the mobile backhaul (see ). In this example, two ACs are needed to service the eNodeB (e.g., distinct VLANs for Control and User Planes).

Example of a CE-PE ACs An example of a request to create the ACs to service the eNodeB is shown in . This example assumes that static addressing is used for both ACs.

Example of a Message Body to Request Two ACes on The Same Link (Not Recommended) shows the message body of a response received from the controller.

Example of a Message Body of a Response to Create Two ACes on The Same Link (Not Recommended) The example shown is not optimal as it includes many redundant data. shows a more compact request that factorizes all the redundant data.

Example of a Message Body to Request Two ACes on The Same Link (Node Profile) A customer may request adding a new AC by simply referring to an existing per-node AC profile as shown in . This AC inherits all the data that was enclosed in the indicated per-node AC profile (IP addressing, routing, etc.).

Example of a Message Body to Add a new AC over an existing link (Node Profile)

Control Precedence over Multiple ACs When multiple ACs are requested by the same customer for the same site, the request can tag one of these ACs as "primary" and the other ones as "secondary". An example of such a request is shown in . In this example, both ACs are bound to the same "group-id", and the "precedence" data node is set as a function of the intended role of each AC (primary or secondary).

An Example Topology for AC Precedence Enforcement

Example of a Message Body to Associate a Precedence Level with ACs

Create Multiple ACs Bound to Multiple CEs shows an example of CEs that are interconnected by a service provider network.

Network Topology Example depicts an example of the message body of a response to a request to instantiate the various ACs that are shown in .

Example of a Message Body of a Request to Create Multiple ACs bound to Multiple CEs

Binding Attachment Circuits to an IETF Network Slice This example shows how the AC service model complements to connect a site to a slice service. First, describes the end-to-end network topology as well the orchestration scopes:

The topology is made up of two sites (site1 and site2), interconnected via a Transport Network (e.g. IP/MPLS Network). A Network Function is deployed within each site in a dedicated IP Subnet.
A 5G SMO is responsible for the deployment Network Functions and the indirect management of a local Gateway (i.e., CE device).
An IETF Network Slice Controller is responsible for the deployment of IETF Network Slices across the TN.

Network Functions are deployed within each site.

An Example of a Network Topology Used to Deploy Slices describes the logical connectivity enforced thanks to both IETF Network Slice and Attachment Circuit models.

Logical Overview shows the message body of the request to create the required ACs using the Attachment Circuit module.

Message Body of a Request to Create Required ACs shows the message body of a reponse received from the controller.

Example of a Message Body of a Response Indicating the Creation of the ACs shows the message body of the request to create the a slice service bound to the ACs created using . Only references to these ACs are included in the Slice Service request. This example assumes that the module that "glues" the service/AC is also supported by the NSC.

Message Body of a Request to Create a Slice Service Referring to the ACs

Connecting a Virtualized Environment Running in a Cloud Provider This example () shows how the AC service model can be used to connect a Cloud Infrastructure to a service provider network. This example makes the following assumptions:

A customer (e.g., Mobile Network Team or partner) has a virtualized infrastructure running in a Cloud Provider. A simplistic deployment is represented here with a set of Virtual Machines running in a Virtual Private Environment. The deployment and management of this infrastructure is achieved via private APIs that are supported by the Cloud Provider: this realization is out of the scope of this document.
The connectivity to the Data Center is achieved thanks to a service based on direct attachment (physical connection), which is delivered upon ordering via an API exposed by the Cloud Provider. When ordering that connection, a unique "Connection Identifier" is generated and returned via the API.
The customer provisions the networking logic within the Cloud Provider based on that unique connection Identifier (i.e., logical interfaces, IP addressing, and routing).

An Example of Realization for Connecting a Cloud Site illustrates the pre-provisioning logic for the physical connection to the Cloud Provider. After this connection is delivered to the service provider, the network inventory is updated with "bearer-reference" set to the value of the "Connection Identifier".

Illustration of Pre-provisioning Next, API workflows can be initiated:

Cloud Provider for the configuration as per (3) above.
Service provider network via the Attachment Circuit model. This request can be used in conjunction with additional requests based on L3SM (VPN provisioning) or Network Slice Service model (5G hybrid Cloud deployment).

shows the message body of the request to create the required ACs to connect the Cloud Provider Virtualized (VM) using the Attachment Circuit module.

Message Body of a Request to Create the ACs for Connecting to the Cloud Provider shows the message body of the response received from the provider. Note that this Cloud Provider mandates the use of MD5 authentication for establishing BGP connections.

The module supports MD5 to basically accommodate the installed BGP base (including by some Cloud Providers). Note that MD5 suffers from the security weaknesses discussed in and .

Message Body of a Response to the Request to Create ACs for Connecting to the Cloud Provider

Acknowledgments Thanks to TBC for the comments.

Contributors Nokia

victor.lopez@nokia.com

Ribbon Communications

Ivan.Bykov@rbbn.com

Huawei

bill.wu@huawei.com

KDDI

ke-oogaki@kddi.com

Vodafone

luis-angel.munoz@vodafone.com