]> A Yang Data Model for IETF Network Slice NBI Huawei Technologies
101 Software Avenue, Yuhua District Nanjing Jiangsu 210012 China lana.wubo@huawei.com
Huawei Technologies
Divyashree Techno Park Bangalore Karnataka 560066 India dhruv.ietf@gmail.com
China Mobile
hanliuyan@chinamobile.com
Nokia
reza.rokui@nokia.com
Routing Area This document provides a YANG data model for the IETF Network Slice NBI (Northbound Interface). The model can be used by a higher level system to request configuration, and management IETF Network Slices from the IETF Network Slice Controller (NSC). The YANG modules in this document conforms to the Network Management Datastore Architecture (NMDA) defined in RFC 8342.
This document provides a YANG data model for the IETF Network Slice NBI. The YANG model discussed in this document is defined based on the description of the IETF Network Slice in and , which is used to operate IETF Network Slice during the IETF Network Slice instantiation. This YANG model supports various oprations on IETF Network Slices such as creation, modification, deletion, and monitoring of IETF Network Slices. The IETF Network Slice Controller (NSC) provides a Northbound Interface (NBI) that allows consumers of network slices to request and monitor IETF network slices. Consumers operate on abstract IETF network slices, with details related to their realization hidden. The NSC takes requests from a management system or other application via an NBI. This interface carries data objects the IETF network slice user provides, describing the needed IETF network slices in terms of topology, applicable service level objectives (SLO), and any monitoring and reporting requirements that may apply. The NBI conveys the generic IETF network slice requirements. These may then be realized using an SBI within the NSC. The YANG model discussed in this document describes the requirements of an IETF Network Slice from the point of view of the consumer, which is classified as Customer Service Model in . It will be up to the management system or NSC (IETF Network Slice controller) to take this model as an input and use other management system or specific configuration models to configure the different network elements to deliver an IETF Network Slice. The YANG models can be used with network management protocols such as NETCONF or RESTCONF . The details of how the IETF network slices are realized by the NSC is out of scope for this document. The IETF Network Slice operational state is included in the same tree as the configuration consistent with Network Management Datastore Architecture .
The keywords "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 BCP14, , when, and only when, they appear in all capitals, as shown here. The following terms are defined in and are used in this specification: client configuration data state data This document makes use of the following terminology introduced in the YANG 1.1 Data Modeling Language : augment data model data node This document also makes use of the following terminology introduced in the IETF Network Slice definition draft : NBI: Northbound Interface NS: IETF Network Slice NSC: IETF Network Slice Controller NSE: Network Slice Endpoint SLO: Service Level Objective This document defines the following new terminology: IETF Network Slice Member (Network-Slice-Member): In the context of an IETF Network Slice, an IETF Network-Slice-Member is an abstract entity which represents a particular connection between a pair of NSEs. An IETF Network Slice can has one or multiple members.
Tree diagrams used in this document follow the notation defined in .
The intention of the IETF Network Slice NBI model is to allow the consumer, e.g. a higher level management system, to request and monitor IETF Network Slices. In particular, the model allows consumers to operate in an abstract, technology-agnostic manner, with realization details hidden. According to the description, the NBI model is applicable to use case such as (but not limited to) Network wholesale services, Network infrastructure sharing among operators, NFV connectivity and Data Center Interconnect and 5G E2E network slice. As shows, in all these use-cases, the NBI model is used by the higher management system (i.e the consumer of the IETF network slice controller ) to communicate with IETF Network Slice controller for life cycle manage of IETF Network Slices including both enablement and monitoring. For example, in 5G E2E network slicing use-case the E2E network slice orchestrator acts as the higher layer system to request the IETF Network Slices. The interface is used to support dynamic IETF Network Slice creation and its lifecycle management to facilitate end-to-end network slice services.
As defined in , an IETF network slice is a logical network connecting a number of endpoints with specified SLOs. The connectivity can be point-to-point, multipoint-to-point, point-to-multipoint or multipoint-to-multipoint. In addition, a minimum set of SLOs is defined, including but not limited to bandwidth, delay, and etc. An example of an IETF network slice is shown in .
| | between endpoints NSE1 to NSEn | Legend: NSE: IETF Network Slice Endpoint O: Represents IETF Network Slice Endpoints]]>
Draft introduces the IETF network slice endpoints (NSEs) which are conceptual points of connection to IETF network slice. As such, they are ingress/egress point where the traffic enters/exits the IETF network slice. In other words, they are the edge of the IETF network slices. When IETF network slice controller (NSC) receives a message via its NBI for creation/modification of an IETF network slice, it uses the provided IETF network slice endpoints to map them to appropriate services/tunnels/paths endpoints in the underlay IETF network. It then uses services/tunnels/paths endpoints to realize the IETF network slice. The IETF Network Slice ("ietf-network-slice") is defined to manage network slices in the IETF network. In particular, the 'ietf-network-slice' module can be used to create, modify, and monitor network slices of an IETF network. The 'ietf-network-slice' module uses two main nodes: list 'ietf-network-slice' and container 'ns-templates' (see ). The 'ietf-network-slice' list includes the set of IETF Network slices managed within IETF network. 'ietf-network-slice' is the data structure that abstracts an IETF Network Slice. Under the "ietf-network-slice", list "ns-endpoint" is used to abstract the NSEs, e.g. NSEs in the example above. The 'ns-templates' container is used by the NSC to maintain a set of common network slice templates that apply to one or several IETF Network Slices. The figure below describes the overall structure of the YANG module:
The 'ns-templates' container () is used by service provider of the NSC to define and maintain a set of common IETF Network Slice templates that apply to one or several IETF Network Slices. The exact definition of the templates is deployment specific to each network provider. The model includes only the identifiers of SLO-templates. When creation of IETF Network slice, the SLO policies can be easily identified. The following shows an example where two network slice templates can be retrieved by the upper layer management system:
The 'ietf-network-slice' is the data structure that abstracts an IETF Network Slice of the IETF network. Each 'ietf-network-slice' is uniquely identified by an identifier: 'ns-id'. An IETF Network Slice has the following main parameters: "ns-id": Is an identifier that is used to uniquely identify the IETF Network Slice within NSC. "ns-description": May be provided to help identify an IETF Network Slice. "ns-topology": Indicates the network topology for the IETF Network Slice: Hub-Spoke, Any-to-Any, and Custom. "status": Enable the control of the operative and administrative status of the IETF Network Slice, can be used as indicator to detect network slice anomalies. "ns-tag": The list is to show the correlation between higher level function and the IETF network slices. If provided, this parameter may be used by IETF Network Slice Controller (NSC) during the realization. It may also be used by NSC for monitoring and assurance of the IETF network slices where NSC can notify the higher system by issuing the notifications. It is noted that a single higher level consumer might have multiple IETF Network Slices for a single application. This attribute may be used by NSC to also correlated multiple IETF network slices for a single application. "ns-slo-policy": Defines SLO policy for the "ietf-network-slice". More description are provided in The "ns-endpoint" is an abstrac entity that represents a set of matching rules applied to an IETF network edge device or a customer network edge device involved in the IETF Network Slice and each 'ns-endpoint' belongs to a single 'ietf-network-slice'. More description are provided in
An IETF Network Slice can be point-to-point (P2P), point-to-multipoint (P2MP), multipoint-to-point (MP2P), or multipoint-to-multipoint (MP2MP) based on the consumer's traffic pattern requirements. Therefore, the "ns-topology" under the node "ietf-network-slice" is required for configuration. The model supports any-to-any, Hub and Spoke (where Hubs can exchange traffic), and the different combinations. New topologies could be added via augmentation. By default, the any-to-any topology is used. In addition, "ep-role" under the node "ns-endpoint" also needs to be defined, which specifies the role of the NSE in a particular Network Slice topology. In the any-to-any topology, all NSEs MUST have the same role, which will be "any-to-any-role". In the Hub-and-Spoke topology, NSEs MUST have a Hub role or a Spoke role.
As defined in , the SLO policy of an IETF Network Slice defines the minimum IETF Network Slice SLO attributes, and additional attributes can be added as needed. "ns-slo-policy" is used to represent a specific SLO policy. During the creation of an IETF Network Slice, the policy can be specified either by a standard SLO template or a customized SLO policy. The model allows multiple SLO attributes to be combined to meet different SLO requirements. For example, some NSs are used for video services and require high bandwidth, some NSs are used for key business services and request low latency and reliability, and some NSs need to provide connections for a large number of NSEs. That is, not all SLO attributes must be specified to meet the particular requirements of a slice. ”ns-metric-bounds“ contains all these variations, which includes a list of "ns-metric-bound" and each "ns-metric-bound" could specify a particular ”metric-type“. ”metric-type" is defined with YANG identity and the YANG module supports the following options: "network-slice-slo-bandwidth": Indicates the guaranteed minimum bandwidth between any two NSE. The unit is data rate per second. And the bandwidth is unidirectional. "network-slice-slo-one-way-delay": Indicates the maximum one-way latency between two NSE. The unit is micro seconds. "network-slice-slo-two-way-delay": Indicates the maximum round trip latency between two NSE. The unit is micro seconds. "network-slice-slo-jitter": Indicates the jitter constraint of the slice maximum permissible delay variation, and is measured by the difference in the one- way delay between sequential packets in a flow. "network-slice-slo-loss": Indicates maximum permissible packet loss rate, which is defined by the ratio of packets dropped to packets transmitted between two endpoints. "network-slice-slo-availability": Is defined as the ratio of up-time to total_time(up-time+down-time), where up-time is the time the IETF Network Slice is available in accordance with the SLOs associated with it. Some other Network Slice objectives, such as MTU and security which can be added when needed. MTU specifies the maximum packet length that the network slice guarantee to be able to carry across. Note: About the definition of SLO parameters, the author is discussing to reuse the TE-Types grouping definition as much as possible, to avoid duplication of definitions. The following shows an example where a network slice policy can be configured:
An IETF Network Slice Endpoint has several characteristics: ”ep-id“: Uniquely identifies the NSE within Network Slice Controller (NSC). The identifier is a string that allows any encoding for the local administration of the IETF Network Slice. "location": is NSE location information that facilities NSC easy identification of a NSE. "ep-role": Is a topology role of a NSE belonging to an IETF network slice, as described in . The "ep-role" leaf defines the role of the endpoint in a particular NS topology. In the NS any-to-any topology, all NSEs MUST have the same role, which will be "any-to-any-role". "node-id": is NSE node information that facilities NSC easy identification of a NSE. "ep-ip": is NSE IP information that facilities NSC easy identification of a NSE. "ns-match-criteria": Is used to define matching policies to apply on a given NSE. "ep-network-access": Is the list that includes the interfaces attached to an edge device of the IETF Network Slice by which the customer traffic is received. "ep-rate-limit": Is to set rate-limiting policies to apply on a given NSE, including ingress and egress traffic to ensure access security. When applied in the incoming direction, the rate-limit is applicable to the traffic from the NSE to the IETF scope Network that passes through the external interface. When Bandwidth is applied to the outgoing direction, it is applied to the traffic from the IETF Network to the NSE of that particular NS. "ep-protocol": Specify the protocol for a NSE for exchanging control-plane information, e.g. L1 signaling protocol or L3 routing protocols,etc. "status": Enable the control of the operative and administrative status of the NSE, can be used as indicator to detect NSE anomalies. An NSE belong to a single IETF Network Slice. An IETF Network Slice involves two or more NSEs. An IETF Network Slice can be modified by adding new "ns-endpoint" or removing existing "ns-endpoint". A NSE is used to define the matching rule on the customer traffic that can be injected to an IETF Network Slice. "network-slice-match-criteria" is defined to support different options. Classification can be based on many criteria, such as: Physical interface: Indicates all the traffic received from the interface belongs to the IETF Network Slice. Logical interface: For example, a given VLAN ID is used to identify an IETF Network Slice. Encapsulation in the traffic header: For example, a source IP address is used to identify an IETF Network Slice. To illustrate the use of NSE parameters, the below are two examples. How the NSC realize the mapping is out of scope for this document. NSE mapping to PE example: As shown in , consumer of the IETF network slice would like to connect two NSEs to satisfy specific service, e.g., Network wholesale services. In this case, the IETF network slice endpoints are mapped to physical interfaces of PE nodes. The IETF network slice controller (NSC) uses “node-id” (PE device ID), "ep-network-access“ (Two PE interfaces ) to map the interfaces and corresponding services/tunnels/paths.
o + | | + + |<----------- S1 ----------->| + + | | + + | |<------ T1 ------>| | + + v v v v + + +----+ +----+ + +-----+ | | PE1|==================| PE2| +-----+ | |----------X | | | | | | | | | | | | X----------| | | |----------X | | | | | | +-----+ | | |==================| | | +-----+ AC +----+ +----+ AC Customer Provider Provider Customer Edge 1 Edge 1 Edge 2 Edge 2 Legend: O: Representation of the IETF network slice endpoints (NSE) +: Mapping of NES to PE or CE nodes on IETF network X: Physical interfaces used for realization of IETF network slice S1: L0/L1/L2/L3 services used for realization of IETF network slice T1: Tunnels used for realization of IETF network slice ]]>
NSE mapping to CE example: As shown in , consumer of the IETF network slice would like to connect two NSEs to provide connectivity between transport portion of 5G RAN to 5G Core network functions. In this scenario, the IETF network slice endpoints (NSE) might be mapped to tunnels endpoints on CE nodes (see 3GPP TS 28.541 V17.1.0 section 6.3.17 EP_Transport). The IETF network slice controller (NSC) uses “node-id” (CE device ID) , "ep-ip" (CE tunnel endpoint IP), "network-slice-match-criteria" (VLAN interface), "ep-network-access“ (Two nexthop interfaces ) to map underlay services/tunnels/paths.
o + | | + + |<----------- S2 ----------->| + + | | + + | |<------ T2 ------>| | + + v v v v + + AC +----+ +----+ + +-----+ | | PE1|==================| PE2| +-----+ | |----------X | | | | | | | | | | | | X----------| | | |----------X | | | | | | +-----+ | | |==================| | | +-----+ AC +----+ +----+ AC Customer Provider Provider Customer Edge 1 Edge 1 Edge 2 Edge 2 Legend: O: Representation of the IETF network slice endpoints (NSE) +: Mapping of NES to PE or CE nodes on IETF network X: Physical interfaces used for realization of IETF network slice S2: L0/L1/L2/L3 services used for realization of IETF network slice T2: Tunnels used for realization of IETF network slice ]]>
An IETF Network Slice is a connectivity with specific SLO characteristics, including bandwidth, QoS metric, etc. The connectivity is a combination of logical connections, represented by Network-Slice-Members. This model also describes performance status of an IETF Network Slice. The statistics are described in the following granularity: Per NS connection: specified in 'network-slice-member-monitoring' under the "network-slice-member" Per NS Endpoint: specified in 'endpoint-monitoring' under the "network-slice-endpoint" This model does not define monitoring enabling methods. The mechanism defined in and can be used for either periodic or on-demand subscription. By specifying subtree filters or xpath filters to 'ns-member' or 'ns-endpoint' ,so that only interested contents will be sent. These mechanisms can be used for monitoring the IETF Network Slice performance status so that the client management system could initiate modification based on the IETF Network Slice running status.
file "ietf-network-slice@2021-02-19.yang" module ietf-network-slice { yang-version 1.1; namespace "urn:ietf:params:xml:ns:yang:ietf-network-slice"; prefix ietf-ns; import ietf-inet-types { prefix inet; } import ietf-yang-types { prefix yang; reference "RFC 6991: Common YANG Types."; } import ietf-te-types { prefix te-types; } organization "IETF Traffic Engineering Architecture and Signaling (TEAS) Working Group"; contact "WG Web: WG List: Editor: Bo Wu : Dhruv Dhody "; description "This module contains a YANG module for the IETF Network Slice. Copyright (c) 2021 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 Simplified BSD License set forth in Section 4.c of the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info). This version of this YANG module is part of RFC XXXX; see the RFC itself for full legal notices."; revision 2021-02-19 { description "initial version."; reference "RFC XXXX: A Yang Data Model for IETF Network Slice Operation"; } /* Features */ /* Identities */ identity network-slice-topology { description "Base identity for IETF Network Slice topology."; } identity any-to-any { base network-slice-topology; description "Identity for any-to-any IETF Network Slice topology."; } identity hub-spoke { base network-slice-topology; description "Identity for Hub-and-Spoke IETF Network Slice topology."; } identity custom { base network-slice-topology; description "Identity of a custom NS topology where Hubs can act as Spoke for certain parts of the network or Spokes as Hubs."; } identity endpoint-role { description "Base identity of a NSE role in an IETF Network Slice topology."; } identity any-to-any-role { base endpoint-role; description "Identity of any-to-any NS."; } identity spoke-role { base endpoint-role; description "A NSE is acting as a Spoke."; } identity hub-role { base endpoint-role; description "A NSE is acting as a Hub."; } identity custom-role { base endpoint-role; description "A NSE is custom role in the NS."; } identity network-slice-slo-metric-type { description "Base identity for Network Slice SLO metric type"; } identity network-slice-slo-two-way-delay { base network-slice-slo-metric-type; description "SLO delay metric."; } identity network-slice-slo-one-way-delay { base network-slice-slo-metric-type; description "SLO delay metric."; } identity network-slice-slo-jitter { base network-slice-slo-metric-type; description "SLO jitter metric."; } identity network-slice-slo-loss { base network-slice-slo-metric-type; description "SLO loss metric ."; } identity network-slice-slo-availability { base network-slice-slo-metric-type; description "SLO availability level."; } identity network-slice-slo-bandwidth { base network-slice-slo-metric-type; description "SLO bandwidth metric."; } identity network-slice-match-type { description "Base identity for Network Slice traffic match type"; } identity network-slice-phy-interface-match { base network-slice-match-type; description "VLAN as Network Slice traffic match criteria."; } identity network-slice-vlan-match { base network-slice-match-type; description "VLAN as Network Slice traffic match criteria."; } identity network-slice-label-match { base network-slice-match-type; description "Label as Network Slice traffic match criteria."; } /* * Identity for availability-type */ identity availability-type { description "Base identity from which specific availability types are derived."; } identity level-1 { base availability-type; description "level 1: 99.9999%"; } identity level-2 { base availability-type; description "level 2: 99.999%"; } identity level-3 { base availability-type; description "level 3: 99.99%"; } identity level-4 { base availability-type; description "level 4: 99.9%"; } identity level-5 { base availability-type; description "level 5: 99%"; } /* typedef */ typedef operational-type { type enumeration { enum up { value 0; description "Operational status UP."; } enum down { value 1; description "Operational status DOWN"; } enum unknown { value 2; description "Operational status UNKNOWN"; } } description "This is a read-only attribute used to determine the status of a particular element"; } typedef ns-monitoring-type { type enumeration { enum one-way { description "represents one-way monitoring type"; } enum two-way { description "represents two-way monitoring type"; } } description "enumerated type of monitoring on a network-slice-member "; } /* Groupings */ grouping status-params { description "Grouping used to join operational and administrative status"; container status { description "Container for status of administration and operational"; leaf admin-enabled { type boolean; description "Administrative Status UP/DOWN"; } leaf oper-status { type operational-type; config false; description "Operations status"; } } } grouping network-slice-match-criteria { description "Grouping for Network Slice match definition."; container ns-match-criteria { description "Describes Network Slice match criteria."; list ns-match-criteria { key "match-type"; description "List of Network Slice traffic criteria"; leaf match-type { type identityref { base network-slice-match-type; } description "Identifies an entry in the list of match-type for the Network Slice."; } leaf value { type string; description "Describes Network Slice match criteria,e.g. IP address, VLAN, etc."; } } } } grouping network-slice-metric-bounds { description "Network Slice metric bounds grouping"; container ns-metric-bounds { description "Network Slice metric bounds container"; list ns-metric-bound { key "metric-type"; description "List of Network Slice metric bounds"; leaf metric-type { type identityref { base network-slice-slo-metric-type; } description "Identifies an entry in the list of metric-types bound for the Network Slice."; } leaf metric-unit { type string; mandatory true; description "The metric unit of the parameter. For example, s, ms, ns, and so on."; } leaf value-description { type string; description "The description of previous value. "; } leaf boundary { type uint64; default "0"; description "Boundary on network-slice-member metric. A zero indicate an unbounded upper limit for the specific metric-type"; } } } } grouping ep-network-accesses { description "Grouping for endpoint network access definition."; list ep-network-access { key "network-access-id"; description "IETF Network Slice endpoint network access related parameters"; leaf network-access-id { type string; description "unique identifier for the referred endpoint network access"; } leaf network-access-description { type string; description "endpoint network access description"; } leaf network-access-node-id { type string; description "EP network access node ID in the case of multi-homing."; } leaf network-access-tp-id { type string; description "EP network access termination port ID."; } leaf network-access-tp-ip { type inet:host; description "The IP address of EP network access."; } } } grouping endpoint-monitoring-parameters { description "Grouping for endpoint-monitoring-parameters."; container ep-monitoring { config false; description "Container for endpoint-monitoring-parameters."; leaf incoming-utilized-bandwidth { type te-types:te-bandwidth; description "Bandwidth utilization that represents the actual utilization of the incoming endpoint."; } leaf incoming-bw-utilization { type decimal64 { fraction-digits 5; range "0..100"; } units "percent"; mandatory true; description "To be used to define the bandwidth utilization as a percentage of the available bandwidth."; } leaf outgoing-utilized-bandwidth { type te-types:te-bandwidth; description "Bandwidth utilization that represents the actual utilization of the incoming endpoint."; } leaf outgoing-bw-utilization { type decimal64 { fraction-digits 5; range "0..100"; } units "percent"; mandatory true; description "To be used to define the bandwidth utilization as a percentage of the available bandwidth."; } } } grouping common-monitoring-parameters { description "Grouping for link-monitoring-parameters."; leaf latency { type yang:gauge64; units "usec"; description "The latency statistics per Network Slice member. [RFC2681] and [RFC7679] discuss round trip times and one-way metrics, respectively"; } leaf jitter { type yang:gauge32; description "The jitter statistics per Network Slice member as defined by [RFC3393]."; } leaf loss-ratio { type decimal64 { fraction-digits 6; range "0 .. 50.331642"; } description "Packet loss as a percentage of the total traffic sent over a configurable interval. The finest precision is 0.000003%. where the maximum 50.331642%."; reference "RFC 7810, section-4.4"; } } grouping geolocation-container { description "A grouping containing a GPS location."; container location { description "A container containing a GPS location."; leaf altitude { type int64; units "millimeter"; description "Distance above the sea level."; } leaf latitude { type decimal64 { fraction-digits 8; range "-90..90"; } description "Relative position north or south on the Earth's surface."; } leaf longitude { type decimal64 { fraction-digits 8; range "-180..180"; } description "Angular distance east or west on the Earth's surface."; } } // gps-location } // geolocation-container grouping endpoint { description "IETF Network Slice endpoint related information"; leaf ep-id { type string; description "unique identifier for the referred IETF Network Slice endpoint"; } leaf ep-description { type string; description "endpoint name"; } leaf ep-role { type identityref { base endpoint-role; } default "any-to-any-role"; description "Role of the endpoint in the IETF Network Slice."; } uses geolocation-container; leaf node-id { type string; description "Uniquely identifies an edge node within the IETF slice network."; } leaf ep-ip { type inet:host; description "The address of the endpoint IP address."; } uses network-slice-match-criteria; uses ep-network-accesses; container ep-rate-limit { description "Container for the asymmetric traffic control"; container incoming-throughput { description "Container for the incoming traffic policy"; leaf maximum-throughput { type te-types:te-bandwidth; description "If maximum-throughput is 0, it means best effort, no minimum throughput is guaranteed."; } } container outgoing-throughput { description "Container for the bandwidth policy"; leaf maximum-throughput { type te-types:te-bandwidth; description "If maximum-throughput is 0, it means best effort, no minimum throughput is guaranteed."; } } } container ep-protocol { description "Describes protocol for the Network Slice Endpoint."; } uses status-params; uses endpoint-monitoring-parameters; } //network-slice-endpoint grouping network-slice-member { description "network-slice-member is described by this container"; leaf ns-member-id { type uint32; description "network-slice-member identifier"; } leaf ns-member-description { type string; description "network-slice-member description"; } container src { description "the source of Network Slice link"; leaf src-ep-id { type leafref { path "/ietf-network-slices/ietf-network-slice/" + "ns-endpoint/ep-id"; } description "reference to source Network Slice endpoint"; } } container dest { description "the destination of Network Slice link "; leaf dest-ep-id { type leafref { path "/ietf-network-slices/ietf-network-slice" + "/ns-endpoint/ep-id"; } description "reference to dest Network Slice endpoint"; } } leaf monitoring-type { type ns-monitoring-type; description "One way or two way monitoring type."; } container ns-member-monitoring { config false; description "SLO status Per network-slice endpoint to endpoint "; uses common-monitoring-parameters; } } //network-slice-member grouping slice-template { description "Grouping for slice-templates."; container ns-templates { description "Contains a set of network slice templates to reference in the IETF network slice."; list slo-template { key "id"; leaf id { type string; description "Identification of the SLO Template to be used. Local administration meaning."; } leaf template-description { type string; description "Description of the SLO policy template."; } description "List for SLO template identifiers."; } } } /* Configuration data nodes */ container ietf-network-slices { description "IETF network-slice configurations"; uses slice-template; list ietf-network-slice { key "ns-id"; description "a network-slice is identified by a network-slice-id"; leaf ns-id { type string; description "A unique network-slice identifier across an IETF NSC "; } leaf ns-description { type string; description "Give more description of the network slice"; } leaf-list ns-tag { type string; description "Network Slice tag for operational management"; } leaf ns-topology { type identityref { base network-slice-topology; } default "any-to-any"; description "Network Slice topology."; } choice ns-slo-policy { description "Choice for SLO policy template. Can be standard template or customized template."; case standard { description "Standard SLO template."; leaf slo-template { type leafref { path "/ietf-network-slices" + "/ns-templates/slo-template/id"; } description "Standard SLO template to be used."; } } case custom { description "Customized SLO template."; container slo-policy { description "Contains the SLO policy."; leaf policy-description { type string; description "Description of the SLO policy."; } uses network-slice-metric-bounds; } } } uses status-params; list ns-endpoint { key "ep-id"; uses endpoint; description "list of endpoints in this slice"; } list ns-member { key "ns-member-id"; description "List of network-slice-member in a slice"; uses network-slice-member; } } //ietf-network-slice list } } ]]>
The YANG module defined in this document 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 NETCONF access control model 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 this YANG module 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) to these data nodes without proper protection can have a negative effect on network operations. o /ietf-network-slice/ietf-network-slices/ietf-network-slice The entries in the list above include the whole network configurations corresponding with the slice which the higher management system requests, and indirectly create or modify the PE or P device configurations. Unexpected changes to these entries could lead to service disruption and/or network misbehavior.
This document registers a URI in the IETF XML registry . Following the format in , the following registration is requested to be made:
This document requests to register a YANG module in the YANG Module Names registry .
The authors wish to thank Sergio Belotti, Qin Wu, Susan Hares, Eric Grey, and many other NS DT members for their helpful comments and suggestions.
The following example describes a simplified service configuration of two IETF Network slice instances: IETF Network Slice 1 on Device1, Device3, and Device4, with any-to-any connection type IETF Network Slice 2 on Device2, Device3, with any-to-any connection type
According to the 3.3.1. Northbound Inteface (NBI) , the IETF Network Slice NBI is a technology-agnostic interface, which is used for a consumer to express requirements for a particular IETF Network Slice. Consumers operate on abstract IETF Network Slices, with details related to their realization hidden. As classified by , the IETF Network Slice NBI is classified as Customer Service Model. This draft analyzes the following existing IETF models to identify the gap between the IETF Network Slice NBI requirements.
The difference between the ACTN VN model and the IETF Network Slice NBI requirements is that the IETF Network Slice NBI is a technology-agnostic interface, whereas the VN model is bound to the IETF TE Topologies. The realization of the IETF Network Slice does not necessarily require the slice network to support the TE technology. The ACTN VN (Virtual Network) model introduced in is the abstract consumer view of the TE network. Its YANG structure includes four components: VN: A Virtual Network (VN) is a network provided by a service provider to a customer for use and two types of VN has defined. The Type 1 VN can be seen as a set of edge-to-edge abstract links. Each link is an abstraction of the underlying network which can encompass edge points of the customer's network, access links, intra-domain paths, and inter-domain links. AP: An AP is a logical identifier used to identify the access link which is shared between the customer and the IETF scoped Network. VN-AP: A VN-AP is a logical binding between an AP and a given VN. VN-member: A VN-member is an abstract edge-to-edge link between any two APs or VN-APs. Each link is formed as an E2E tunnel across the underlying networks. The Type 1 VN can be used to describe IETF Network Slice connection requirements. However, the Network Slice SLO and Network Slice Endpoint are not clearly defined and there's no direct equivalent. For example, the SLO requirement of the VN is defined through the IETF TE Topologies YANG model, but the TE Topologies model is related to a specific implementation technology. Also, VN-AP does not define "network-slice-match-criteria“ to specify a specific NSE belonging to an IETF Network Slice.
The difference between the IETF Network Slice NBI requirements and the IETF basic network model is that the IETF Network Slice NBI requests abstract consumer IETF Network Slices, with details related to the slice Network hidden. But the IETF network model is used to describe the interconnection details of a Network. The customer service model does not need to provide details on the Network. For example, IETF Network Topologies YANG data model extension introduced in Transport Network Slice YANG Data Model includes three major parts: Network: a transport network list and an list of nodes contained in the network Link: "links" list and "termination points" list describe how nodes in a network are connected to each other Support network: vertical layering relationships between IETF Network Slice networks and underlay networks Based on this structure, the IETF Network Slice-specific SLO attributes nodes are augmented on the Network Topologies model,, e.g. isolation etc. However, this modeling design requires the slice network to expose a lot of details of the network, such as the actual topology including nodes interconnection and different network layers interconnection.
5G is a use case of the IETF Network Slice and 5G End-to-end Network Slice Mapping from the view of IETF Network defines two types of Network Slice interconnection and differentiation methods: by physical interface or by TNSII (Transport Network Slice Interworking Identifier). TNSII is a field in the packet header when different 5G wireless network slices are transported through a single physical interfaces of the IETF scoped Network. In the 5G scenario, “network-slice-match-criteria” refers to TNSII.
As shown in the figure, gNodeB 1 and gNodeB 2 use IP gNB1 and IP gNB2 to communicate with the IETF network, respectively. In addition, the traffic of NS1 and NS2 on gNodeB 1 and gNodeB 2 is transmitted through the same access links to the IETF slice network. The IETF slice network need to to distinguish different IETF Network Slice traffic of same gNB. Therefore, in addition to using "node-id" and "port-id" to identify a Network Slice Endpont, other information is needed along with these parameters to uniquely distinguish a NSE. For example, VLAN IDs in the user traffic can be used to distinguish the NSEs of gNBs and UPFs.