A Yang Data Model for IETF Network Slice NBI
draft-wd-teas-ietf-network-slice-nbi-yang-03
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Active Internet-Draft (individual)
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Bo Wu
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Dhruv Dhody
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Reza Rokui
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Tarek Saad
,
Liuyan Han
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Last updated |
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2021-07-09
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draft-wd-teas-transport-slice-yang
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ietf-network-slice@2021-07-06.yang:
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# read /a/www/ietf-ftp/yang/rfcmod/ietf-routing-types@2017-12-04.yang
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Network Working Group B. Wu
Internet-Draft D. Dhody
Intended status: Standards Track Huawei Technologies
Expires: January 10, 2022 R. Rokui
Nokia
T. Saad
Juniper Networks
L. Han
China Mobile
July 9, 2021
A Yang Data Model for IETF Network Slice NBI
draft-wd-teas-ietf-network-slice-nbi-yang-03
Abstract
This document provides a YANG data model for the IETF Network Slice
Controller (NSC) Northbound Interface (NBI). The model can be used
by a IETF Network Slice customer to request configuration, and
management IETF Network Slice services from the IETF NSC.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on January 10, 2022.
Copyright Notice
Copyright (c) 2021 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
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carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions used in this document . . . . . . . . . . . . . . 3
2.1. Tree Diagrams . . . . . . . . . . . . . . . . . . . . . . 4
3. IETF Network Slice NBI Model Usage . . . . . . . . . . . . . 4
4. IETF Network Slice NBI Model Overview . . . . . . . . . . . . 5
5. IETF Network Slice Templates . . . . . . . . . . . . . . . . 9
6. IETF Network Slice Modeling Description . . . . . . . . . . . 10
6.1. IETF Network Slice Connectivity Type . . . . . . . . . . 11
6.2. IETF Network Slice SLO and SLE Policy . . . . . . . . . . 11
6.3. IETF Network Slice Endpoint (NSE) . . . . . . . . . . . . 13
7. IETF Network Slice Monitoring . . . . . . . . . . . . . . . . 16
8. IETF Network Slice NBI Module . . . . . . . . . . . . . . . . 17
9. Security Considerations . . . . . . . . . . . . . . . . . . . 35
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 36
11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 36
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 37
12.1. Normative References . . . . . . . . . . . . . . . . . . 37
12.2. Informative References . . . . . . . . . . . . . . . . . 38
Appendix A. IETF Network Slice NBI Model Usage Example . . . . . 39
Appendix B. Comparison with Other Possible Design choices for
IETF Network Slice NBI . . . . . . . . . . . . . . . 42
B.1. ACTN VN Model Augmentation . . . . . . . . . . . . . . . 42
B.2. RFC8345 Augmentation Model . . . . . . . . . . . . . . . 43
Appendix C. Appendix B IETF Network Slice Match Criteria . . . . 43
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 45
1. Introduction
This document provides a YANG [RFC7950] 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
[I-D.ietf-teas-ietf-network-slices], which is used to operate IETF
Network Slice during the IETF Network Slice instantiation. This YANG
model supports various operations on IETF Network Slices such as
creation, modification, deletion, and monitoring of IETF Network
Slices.
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The IETF Network Slice Controller (NSC) provides a Northbound
Interface (NBI) that allows customers of network slices to request
and monitor IETF network slices.
The NBI carries information that the IETF network slice customer
provides, describing generic requirements of connectivity, service
level objectives (SLO), etc. and also monitoring and reporting
requirements that may apply. It is an abstract interface that hides
excessive technology-related information which may then be realized
using some technology-specific Southbound Interface (SBI) by the NSC.
The YANG model discussed in this document describes the requirements
of an IETF Network Slice from the point of view of the customer,
which is classified as Customer Service Model in [RFC8309].
It will be up to the management system or NSC 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 [RFC6241] or RESTCONF [RFC8040]. 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 [RFC8342].
2. Conventions used in this document
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, [RFC2119], [RFC8174] when, and only when, they appear in all
capitals, as shown here.
The following terms are defined in [RFC6241] and are used in this
specification:
o client
o configuration data
o state data
This document makes use of the following terminology introduced in
the YANG 1.1 Data Modeling Language [RFC7950]:
o augment
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o data model
o data node
This document also makes use of the terms introduced in the Framework
for IETF Network Slices [I-D.ietf-teas-ietf-network-slices]:
o NBI: Northbound Interface
o NS: IETF Network Slice
o NSC: IETF Network Slice Controller
o NSE: Network Slice Endpoint
o SLO: Service Level Objective
o SLE: Service Level Expectation
This document defines the following term:
o IETF Network Slice Connection (NS-Connection): In the context of
an IETF Network Slice, an IETF NS-Connection is an abstract entity
which represents a particular connection between a pair of NSEs.
An IETF Network Slice can has one or multiple NS-Connections.
2.1. Tree Diagrams
Tree diagrams used in this document follow the notation defined in
[RFC8340].
3. IETF Network Slice NBI Model Usage
The intention of the IETF Network Slice NBI model is to allow the
customer, e.g. a higher-level management system, to request and
monitor IETF Network Slices. In particular, the model allows
customers to operate on abstract and technology-agnostic manner, with
details of the IETF Network Slices realization hidden.
According to the [I-D.ietf-teas-ietf-network-slices] description, the
NBI model is applicable to use cases such as (but not limited to)
network wholesale services, network infrastructure sharing among
operators, NFV connectivity, Data Center Interconnect, and 5G E2E
network slice.
As shown in Figure 1, in all these use-cases, the NBI model is used
by the higher management system to communicate with IETF Network
Slice controller for life cycle manage of IETF Network Slices
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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.
+----------------------------------------+
| IETF Network Slice Customer |
| |
+----------------+-----------------------+
|
|
|IETF Network Slice NBI YANG
|
+---------------------+--------------------------+
| IETF Network Slice Controller (NSC) |
+------------------------------------------------+
Figure 1: IETF Network Slice NBI Model Context
4. IETF Network Slice NBI Model Overview
As defined in [I-D.ietf-teas-ietf-network-slices], an IETF network
slice is a logical network connecting a number of endpoints with
specified SLOs. The connectivity type can be Hub-and-Spoke, any-to-
any, or custom connectivity type. In addition, a minimum set of SLOs
is defined, including but not limited to bandwidth, latency, and etc.
An example of an IETF network slice is shown in Figure 2 .
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+----------------------------------------------+
| |
NSE1 O------------------+ |
. +---------------------------O NSE2
. | .
. | Any-to-Any .
. | .
. +---------------------------O NSEn
NSEm O------------------+ |
| |
+----------------------------------------------+
| |
|<-----------An IETF Network Slice ---------->|
| between endpoints NSE1 to NSEn |
Legend:
NSE: IETF Network Slice Endpoint
O: Represents IETF Network Slice Endpoints
Figure 2: An IETF Network Slice Example
[I-D.ietf-teas-ietf-network-slices] 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 Figure 3).
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.
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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:
module: ietf-network-slice
+--rw network-slices
+--rw ns-slo-sle-templates
| +--rw ns-slo-sle-template* [id]
| +--rw id string
| +--rw template-description? string
+--rw network-slice* [ns-id]
+--rw ns-id string
+--rw ns-description? string
+--rw ns-tag* string
+--rw ns-connectivity-type? identityref
+--rw (ns-slo-sle-policy)?
| +--:(standard)
| | +--rw slo-sle-template? leafref
| +--:(custom)
| +--rw slo-policy
| | +--rw policy-description? string
| | +--rw ns-metric-bounds
| | +--rw ns-metric-bound* [metric-type]
| | +--rw metric-type identityref
| | +--rw metric-unit string
| | +--rw value-description? string
| | +--rw bound? uint64
| +--rw sle-policies
| +--rw security-sle* identityref
| +--rw isolation? identityref
| +--rw max-occupancy-level? uint8
+--rw status
| +--rw admin-enabled? boolean
| +--ro oper-status? operational-type
+--rw ns-endpoints
| +--rw ns-endpoint* [ep-id]
| +--rw ep-id string
| +--rw ep-description? string
| +--rw ep-role? identityref
| +--rw location
| | +--rw altitude? int64
| | +--rw latitude? decimal64
| | +--rw longitude? decimal64
| +--rw node-id? string
| +--rw ep-ip? inet:host
| +--rw ns-match-criteria
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| | +--rw ns-match-criterion* [match-type]
| | +--rw match-type identityref
| | +--rw values* [index]
| | +--rw index uint8
| | +--rw value? string
| +--rw ep-network-access-points
| | +--rw ep-network-access-point* [network-access-id]
| | +--rw network-access-id string
| | +--rw network-access-description? string
| | +--rw network-access-node-id? string
| | +--rw network-access-tp-id? string
| | +--rw network-access-tp-ip? inet:host
| | +--rw ep-rate-limit
| | +--rw incoming-rate-limit?
| | | te-types:te-bandwidth
| | +--rw outgoing-rate-limit?
| | te-types:te-bandwidth
| +--rw ep-rate-limit
| | +--rw incoming-rate-limit? te-types:te-bandwidth
| | +--rw outgoing-rate-limit? te-types:te-bandwidth
| +--rw ep-protocol
| +--rw status
| | +--rw admin-enabled? boolean
| | +--ro oper-status? operational-type
| +--ro ep-monitoring
| +--ro incoming-utilized-bandwidth?
| | te-types:te-bandwidth
| +--ro incoming-bw-utilization decimal64
| +--ro outgoing-utilized-bandwidth?
| | te-types:te-bandwidth
| +--ro outgoing-bw-utilization decimal64
+--rw ns-connections
+--rw ns-connection* [ns-connection-id]
+--rw ns-connection-id uint32
+--rw ns-connection-description? string
+--rw src
| +--rw src-ep-id? leafref
+--rw dest
| +--rw dest-ep-id? leafref
+--rw (ns-slo-sle-policy)?
| +--:(standard)
| | +--rw slo-sle-template? leafref
| +--:(custom)
| +--rw slo-policy
| | +--rw policy-description? string
| | +--rw ns-metric-bounds
| | +--rw ns-metric-bound* [metric-type]
| | +--rw metric-type identityref
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| | +--rw metric-unit string
| | +--rw value-description? string
| | +--rw bound? uint64
| +--rw sle-policies
| +--rw security-sle* identityref
| +--rw isolation? identityref
| +--rw max-occupancy-level? uint8
+--rw monitoring-type? ns-monitoring-type
+--ro ns-connection-monitoring
+--ro latency? yang:gauge64
+--ro jitter? yang:gauge32
+--ro loss-ratio? decimal64
Figure 3
5. IETF Network Slice Templates
The 'ns-templates' container (Figure 3) 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 and SLE templates.
When creation of IETF Network slice, the SLO and SLE policies can be
easily identified.
The following shows an example where two network slice templates can
be retrieved by the upper layer management system:
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{
"ietf-network-slices": {
"ns-templates": {
"slo-sle-template": [
{
"id":"GOLD-template",
"template-description": "Two-way bandwidth: 1 Gbps,
one-way latency 100ms "
"sle-isolation":"ns-isolation-shared",
},
{
"id":"PLATINUM-template",
"template-description": "Two-way bandwidth: 1 Gbps,
one-way latency 50ms "
"sle-isolation":"ns-isolation-dedicated",
},
],
}
}
}
6. IETF Network Slice Modeling Description
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:
o "ns-id": Is an identifier that is used to uniquely identify the
IETF Network Slice within NSC.
o "ns-description": Gives some description of an IETF Network Slice
service.
o "ns-connectivity-type": Indicates the network connectivity type
for the IETF Network Slice: Hub-and-Spoke, any-to-any, or custom
type.
o "status": Is used to show the operative and administrative status
of the IETF Network Slice, and can be used as indicator to detect
network slice anomalies.
o "ns-tag": Is used 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
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higher system by issuing the notifications. It is noted that a
single higher level customer 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.
o "ns-slo-sle-policy": Defines SLO and SLE policies for the "ietf-
network-slice". More description are provided in Section 6.2
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 Section 6.3
6.1. IETF Network Slice Connectivity Type
Based on the customer's traffic pattern requirements, an IETF Network
Slice connection type could be point-to-point (P2P), point-to-
multipoint (P2MP), multipoint-to-point (MP2P), or multipoint-to-
multipoint (MP2MP). The "ns-connectivity-type" under the node "ietf-
network-slice" is used for this.
For the connectivity requirements, the model proposes to support any-
to-any, Hub-and-Spoke (where Hubs can exchange traffic), and the
custom. By default, the any-to-any is used. New connectivity type
could be added via augmentation or by list of 'ns-connection'
specified.
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 connectivity type. In the any-to-any, all NSEs MUST have the
same role, which will be "any-to-any-role". In the Hub-and-Spoke,
NSEs MUST have a Hub role or a Spoke role.
6.2. IETF Network Slice SLO and SLE Policy
As defined in [I-D.ietf-teas-ietf-network-slices], 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-sle-policy" is used to represent specific SLO and SLE
policies. During the creation of an IETF Network Slice, the policy
can be specified either by a standard SLO and SLO template or a
customized SLO and SLE policy.
The policy could both apply one per Network Slice or per connection
'ns-connection'.
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The model allows multiple SLO and SLE attributes to be combined to
meet different SLO and SLE 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 or SLE 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:
"ns-slo-one-way-bandwidth": Indicates the guaranteed minimum
bandwidth between any two NSE. And the bandwidth is
unidirectional.
"ns-slo-two-way-bandwidth": Indicates the guaranteed minimum
bandwidth between any two NSE. And the bandwidth is
bidirectional.
"network-slice-slo-one-way-latency": Indicates the maximum one-way
latency between two NSE.
"network-slice-slo-two-way-latency": Indicates the maximum round-
trip latency between two NSE.
"ns-slo-one-way-delay-variation": Indicates the jitter constraint
of the slice maximum permissible delay variation, and is measured
by the difference in the one-way latency between sequential
packets in a flow.
"ns-slo-two-way-delay-variation": Indicates the jitter constraint
of the slice maximum permissible delay variation, and is measured
by the difference in the two-way latency between sequential
packets in a flow.
"ns-slo-one-way-packet-loss": Indicates maximum permissible packet
loss rate, which is defined by the ratio of packets dropped to
packets transmitted between two endpoints.
"ns-slo-two-way-packet-loss": Indicates maximum permissible packet
loss rate, which is defined by the ratio of packets dropped to
packets transmitted between two endpoints.
"ns-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
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Network Slice is available in accordance with the SLOs associated
with it.
Some other Network Slice SLOs or SLEs could be extended when needed.
The following shows an example where a network slice policy can be
configured:
{
"ietf-network-slices": {
"ietf-network-slice": {
"slo-policy": {
"policy-description":"video-service-policy",
"ns-metric-bounds": {
"ns-metric-bound": [
{
"metric-type": "ns-slo-one-way-bandwidth",
"metric-unit": "mbps"
"bound": "1000"
},
{
"metric-type": "ns-slo-availability",
"bound": "99.9%"
},
],
}
}
}
}
}
6.3. IETF Network Slice Endpoint (NSE)
An IETF Network Slice Endpoint has several characteristics:
o "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.
o "location": Indicates NSE location information that facilities NSC
easy identification of a NSE.
o "ep-role": Represents a connectivity type role of a NSE belonging
to an IETF network slice, as described in Section 6.1. The "ep-
role" leaf defines the role of the endpoint in a particular NS
connectivity type. In the any-to-any, all NSEs MUST have the same
role, which will be "any-to-any-role".
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o "node-id": The NSE node information facilities NSC with easy
identification of a NSE.
o "ep-ip": The NSE IP information facilities NSC with easy
identification of a NSE.
o "ns-match-criteria": A matching policies to apply on a given NSE.
o "ep-network-access-points": The list of the interfaces attached to
an edge device of the IETF Network Slice by which the customer
traffic is received.
o "ep-rate-limit": Set the 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.
o "ep-protocol": Specify the protocol for a NSE for exchanging
control-plane information, e.g. L1 signaling protocol or L3
routing protocols,etc.
o "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:
o Physical interface: Indicates all the traffic received from the
interface belongs to the IETF Network Slice.
o Logical interface: For example, a given VLAN ID is used to
identify an IETF Network Slice.
o Encapsulation in the traffic header: For example, a source IP
address is used to identify an IETF Network Slice.
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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.
o NSE mapping to PE example: As shown in Figure 4 , customer 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-points' (Two PE interfaces
) to map the interfaces and corresponding services/tunnels/paths.
NSE1 NSE2
(With PE1 parameters) (with PE2 parameters)
o<--------- IETF Network Slice 1 ------->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
Figure 4
o NSE mapping to CE-PE interface example: As shown in Figure 5 ,
customer 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 the respective PE-CE interface
(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'
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(VLAN interface), 'ep-network-access-points' (Two nexthop
interfaces ) to map underlay services/tunnels/paths.
NSE3 NSE4
(With CE1 parameters) (with CE2 parameters)
o<--------- IETF Network Slice 2 ------->o
+ | | +
+ |<----------- S2 ----------->| +
+ | | +
+ | |<------ T2 ------>| | +
+ v v v v +
AC +----+ +----+ 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 NSE to PE or CE-PE interfaces 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
Figure 5
7. IETF Network Slice Monitoring
An IETF Network Slice is a connectivity with specific SLO
characteristics, including bandwidth, latency, etc. The connectivity
is a combination of logical unidirectional connections, represented
by 'ns-connection'.
This model also describes performance status of an IETF Network
Slice. The statistics are described in the following granularity:
o Per NS connection: specified in 'ns-connection-monitoring' under
the "ns-connection"
o Per NS Endpoint: specified in 'ep-monitoring' under the "ns-
endpoint"
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This model does not define monitoring enabling methods. The
mechanism defined in [RFC8640] and [RFC8641] can be used for either
periodic or on-demand subscription.
By specifying subtree filters or xpath filters to 'ns-connection' 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 customer management system could
initiate modification based on the IETF Network Slice running status.
8. IETF Network Slice NBI Module
The "ietf-network-slice" module uses types defined in [RFC6991],
[RFC8776].
<CODE BEGINS> file "ietf-network-slice@2021-07-06.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;
reference
"RFC 6991: Common YANG Types.";
}
import ietf-yang-types {
prefix yang;
reference
"RFC 6991: Common YANG Types.";
}
import ietf-te-types {
prefix te-types;
reference
"RFC 8776: Common YANG Data Types for Traffic Engineering.";
}
organization
"IETF Traffic Engineering Architecture and Signaling (TEAS)
Working Group";
contact
"WG Web: <https://tools.ietf.org/wg/teas/>
WG List: <mailto:teas@ietf.org>
Editor: Bo Wu <lana.wubo@huawei.com>
: Dhruv Dhody <dhruv.ietf@gmail.com>
: Reza Rokui <reza.rokui@nokia.com>
: Tarek Saad <tsaad@juniper.net>";
description
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"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 2021-07-06 {
description
"initial version.";
reference
"RFC XXXX: A Yang Data Model for IETF Network Slice Operation";
}
/* Features */
/* Identities */
identity ns-isolation-type {
description
"Base identity for IETF Network slice isolation level.";
}
identity ns-isolation-shared {
base ns-isolation-type;
description
"Shared resources (e.g. queues) are associated with the Network
Slice traffic. Hence, the IETF network slice traffic can be
impacted by effects of other services traffic sharing
the same resources.";
}
identity ns-isolation-dedicated {
base ns-isolation-type;
description
"Dedicated resources (e.g. queues) are associated with the Network
Slice traffic. Hence, the IETF network slice traffic is isolated
from other servceis traffic sharing the same resources.";
}
identity ns-security-type {
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description
"Base identity for for IETF Network security level.";
}
identity ns-security-authenticate {
base ns-security-type;
description
"IETF Network Slice requires authentication.";
}
identity ns-security-integrity {
base ns-security-type;
description
"IETF Network Slice requires data integrity.";
}
identity ns-security-encryption {
base ns-security-type;
description
"IETF Network Slice requires data encryption.";
}
identity ns-connectivity-type {
description
"Base identity for IETF Network Slice topology.";
}
identity any-to-any {
base ns-connectivity-type;
description
"Identity for any-to-any IETF Network Slice topology.";
}
identity hub-spoke {
base ns-connectivity-type;
description
"Identity for Hub-and-Spoke IETF Network Slice topology.";
}
identity custom {
base ns-connectivity-type;
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
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"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 ns-slo-metric-type {
description
"Base identity for IETF Network Slice SLO metric type.";
}
identity ns-slo-one-way-bandwidth {
base ns-slo-metric-type;
description
"SLO bandwidth metric. Minimum guaranteed bandwidth between
two endpoints at any time and is measured unidirectionally";
}
identity ns-slo-two-way-bandwidth {
base ns-slo-metric-type;
description
"SLO bandwidth metric. Minimum guaranteed bandwidth between
two endpoints at any time";
}
identity ns-slo-one-way-latency {
base ns-slo-metric-type;
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description
"SLO one-way latency is upper bound of network latency when
transmitting between two endpoints. The metric is defined in
RFC7679";
}
identity ns-slo-two-way-latency {
base ns-slo-metric-type;
description
"SLO two-way latency is upper bound of network latency when
transmitting between two endpoints. The metric is defined in
RFC2681";
}
identity ns-slo-one-way-delay-variation {
base ns-slo-metric-type;
description
"SLO one-way delay variation is defined by RFC3393, is the
difference in the one-way delay between sequential packets
between two endpoints.";
}
identity ns-slo-two-way-delay-variation {
base ns-slo-metric-type;
description
"SLO two-way delay variation is defined by RFC5481, is the
difference in the round-trip delay between sequential packets
between two endpoints.";
}
identity ns-slo-one-way-packet-loss {
base ns-slo-metric-type;
description
"SLO loss metric. The ratio of packets dropped to packets
transmitted between two endpoints in one-way
over a period of time as specified in RFC7680";
}
identity ns-slo-two-way-packet-loss {
base ns-slo-metric-type;
description
"SLO loss metric. The ratio of packets dropped to packets
transmitted between two endpoints in two-way
over a period of time as specified in RFC7680";
}
identity ns-slo-availability {
base ns-slo-metric-type;
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description
"SLO availability level.";
}
identity ns-match-type {
description
"Base identity for IETF Network Slice traffic match type.";
}
identity ns-phy-interface-match {
base ns-match-type;
description
"Use the physical interface as match criteria for the IETF
Network Slice traffic.";
}
identity ns-vlan-match {
base ns-match-type;
description
"Use the VLAN ID as match criteria for the IETF Network Slice
traffic.";
}
identity ns-label-match {
base ns-match-type;
description
"Use the MPLS label as match criteria for the IETF Network
Slice traffic.";
}
/*
* 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;
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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 {
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type enumeration {
enum one-way {
description
"Represents one-way measurments monitoring type.";
}
enum two-way {
description
"represents two-way measurements monitoring type.";
}
}
description
"An enumerated type for monitoring on a IETF Network Slice
connection.";
}
/* Groupings */
grouping status-params {
description
"A grouping used to join operational and administrative status.";
container status {
description
"A container for the administrative and operational state.";
leaf admin-enabled {
type boolean;
description
"The administrative status.";
}
leaf oper-status {
type operational-type;
config false;
description
"The operational status.";
}
}
}
grouping ns-match-criteria {
description
"A grouping for the IETF Network Slice match definition.";
container ns-match-criteria {
description
"Describes the IETF Network Slice match criteria.";
list ns-match-criterion {
key "match-type";
description
"List of the IETF Network Slice traffic match criteria.";
leaf match-type {
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type identityref {
base ns-match-type;
}
description
"Identifies an entry in the list of the IETF Network Slice
match criteria.";
}
list values {
key "index";
description
"List of match criteria values.";
leaf index {
type uint8;
description
"Index of an entry in the list.";
}
leaf value {
type string;
description
"Describes the IETF Network Slice match criteria, e.g.
IP address, VLAN, etc.";
}
}
}
}
}
grouping ns-connection-group-metric-bounds {
description
"Grouping of Network Slice metric bounds that
are shared amongst multiple connections of a Network
Slice.";
leaf ns-slo-shared-bandwidth {
type te-types:te-bandwidth;
description
"A limit on the bandwidth that is shared amongst
multiple connections of an IETF Network Slice.";
}
}
grouping ns-sles {
description
"Indirectly Measurable Objectives of a IETF Network
Slice.";
container sle-policies {
description
"Container for the policy of SLEs applicable to
IETF Network Slice.";
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leaf-list security-sle {
type identityref {
base ns-security-type;
}
description
"The IETF Network Slice security SLE(s)";
}
leaf isolation {
type identityref {
base ns-isolation-type;
}
default "ns-isolation-shared";
description
"The IETF Network Slice isolation SLE requirement.";
}
leaf max-occupancy-level {
type uint8 {
range "1..100";
}
description
"The maximal occupancy level specifies the number of flows to
be admitted.";
}
}
}
grouping ns-metric-bounds {
description
"IETF Network Slice metric bounds grouping.";
container ns-metric-bounds {
description
"IETF Network Slice metric bounds container.";
list ns-metric-bound {
key "metric-type";
description
"List of IETF Network Slice metric bounds.";
leaf metric-type {
type identityref {
base ns-slo-metric-type;
}
description
"Identifies an entry in the list of metric type
bounds for the IETF Network Slice.";
}
leaf metric-unit {
type string;
mandatory true;
description
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"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 bound {
type uint64;
default "0";
description
"The Bound on the Network Slice connection metric. A
zero indicate an unbounded upper limit for the
specific metric-type.";
}
}
}
}
grouping ep-network-access-points {
description
"Grouping for the endpoint network access definition.";
container ep-network-access-points {
description
"List of network access points.";
list ep-network-access-point {
key "network-access-id";
description
"The IETF Network Slice network access points
related parameters.";
leaf network-access-id {
type string;
description
"Uniquely identifier a network access point.";
}
leaf network-access-description {
type string;
description
"The network access point description.";
}
leaf network-access-node-id {
type string;
description
"The network access point node ID in the case of
multi-homing.";
}
leaf network-access-tp-id {
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type string;
description
"The termination port ID of the EP network access
point.";
}
leaf network-access-tp-ip {
type inet:host;
description
"The IP address of the EP network access point.";
}
/* Per ep-network-access-point rate limits */
uses ns-rate-limit;
}
}
}
grouping endpoint-monitoring-parameters {
description
"Grouping for the endpoint monitoring parameters.";
container ep-monitoring {
config false;
description
"Container for endpoint monitoring parameters.";
leaf incoming-utilized-bandwidth {
type te-types:te-bandwidth;
description
"Incoming bandwidth utilization at an 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
"Outgoing bandwidth utilization at an endpoint.";
}
leaf outgoing-bw-utilization {
type decimal64 {
fraction-digits 5;
range "0..100";
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}
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 connection.
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 {
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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 ns-rate-limit {
description
"The Network Slice rate limit grouping.";
container ep-rate-limit {
description
"Container for the asymmetric traffic control";
leaf incoming-rate-limit {
type te-types:te-bandwidth;
description
"The rate-limit imposed on incoming traffic.";
}
leaf outgoing-rate-limit {
type te-types:te-bandwidth;
description
"The rate-limit imposed on outgoing traffic.";
}
}
}
grouping endpoint {
description
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"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 ns-match-criteria;
uses ep-network-access-points;
uses ns-rate-limit;
/* Per NSE rate limits */
container ep-protocol {
description
"Describes protocol for the Network Slice Endpoint.";
}
uses status-params;
uses endpoint-monitoring-parameters;
}
//ns-endpoint
grouping ns-connection {
description
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"The Network Slice connection is described in this container.";
leaf ns-connection-id {
type uint32;
description
"The Network Slice connection identifier";
}
leaf ns-connection-description {
type string;
description
"The Network Slice connection description";
}
container src {
description
"the source of Network Slice link";
leaf src-ep-id {
type leafref {
path "/network-slices/network-slice"
+ "/ns-endpoints/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 "/network-slices/network-slice"
+ "/ns-endpoints/ns-endpoint/ep-id";
}
description
"reference to dest Network Slice endpoint";
}
}
uses ns-slo-sle-policy;
/* Per connection ns-slo-sle-policy overrides
* the per network slice ns-slo-sle-policy.
*/
leaf monitoring-type {
type ns-monitoring-type;
description
"One way or two way monitoring type.";
}
container ns-connection-monitoring {
config false;
description
"SLO status Per network-slice endpoint to endpoint ";
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uses common-monitoring-parameters;
}
}
//ns-connection
grouping slice-template {
description
"Grouping for slice-templates.";
container ns-slo-sle-templates {
description
"Contains a set of network slice templates to
reference in the IETF network slice.";
list ns-slo-sle-template {
key "id";
leaf id {
type string;
description
"Identification of the Service Level Objective (SLO)
and Service Level Expectation (SLE) template to be used.
Local administration meaning.";
}
leaf template-description {
type string;
description
"Description of the SLO & SLE policy template.";
}
description
"List for SLO and SLE template identifiers.";
}
}
}
/* Configuration data nodes */
grouping ns-slo-sle-policy {
description
"Network Slice policy grouping.";
choice ns-slo-sle-policy {
description
"Choice for SLO and SLE policy template.
Can be standard template or customized template.";
case standard {
description
"Standard SLO template.";
leaf slo-sle-template {
type leafref {
path "/network-slices"
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+ "/ns-slo-sle-templates/ns-slo-sle-template/id";
}
description
"Standard SLO and SLE 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 ns-metric-bounds;
}
uses ns-sles;
}
}
}
container network-slices {
description
"IETF network-slice configurations";
uses slice-template;
list network-slice {
key "ns-id";
description
"a network-slice is identified by a ns-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-connectivity-type {
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type identityref {
base ns-connectivity-type;
}
default "any-to-any";
description
"Network Slice topology.";
}
uses ns-slo-sle-policy;
uses status-params;
container ns-endpoints {
description
"Endpoints";
list ns-endpoint {
key "ep-id";
uses endpoint;
description
"list of endpoints in this slice";
}
}
container ns-connections {
description
"Connections container";
list ns-connection {
key "ns-connection-id";
description
"List of Network Slice connections.";
uses ns-connection;
}
}
}
//ietf-network-slice list
}
}
<CODE ENDS>
9. Security Considerations
The YANG module defined in this document is designed to be accessed
via network management protocols such as NETCONF [RFC6241] or
RESTCONF [RFC8040]. The lowest NETCONF layer is the secure transport
layer, and the mandatory-to-implement secure transport is Secure
Shell (SSH) [RFC6242]. The lowest RESTCONF layer is HTTPS, and the
mandatory-to-implement secure transport is TLS [RFC8446].
The NETCONF access control model [RFC8341] provides the means to
restrict access for particular NETCONF or RESTCONF users to a
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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/network-slices/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.
10. IANA Considerations
This document registers a URI in the IETF XML registry [RFC3688].
Following the format in [RFC3688], the following registration is
requested to be made:
URI: urn:ietf:params:xml:ns:yang:ietf-network-slice
Registrant Contact: The IESG.
XML: N/A, the requested URI is an XML namespace.
This document requests to register a YANG module in the YANG Module
Names registry [RFC7950].
Name: ietf-network-slice
Namespace: urn:ietf:params:xml:ns:yang:ietf-network-slice
Prefix: ietf-ns
Reference: RFC XXXX
11. Acknowledgments
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.
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12. References
12.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
DOI 10.17487/RFC3688, January 2004,
<https://www.rfc-editor.org/info/rfc3688>.
[RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
and A. Bierman, Ed., "Network Configuration Protocol
(NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
<https://www.rfc-editor.org/info/rfc6241>.
[RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure
Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011,
<https://www.rfc-editor.org/info/rfc6242>.
[RFC6991] Schoenwaelder, J., Ed., "Common YANG Data Types",
RFC 6991, DOI 10.17487/RFC6991, July 2013,
<https://www.rfc-editor.org/info/rfc6991>.
[RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
RFC 7950, DOI 10.17487/RFC7950, August 2016,
<https://www.rfc-editor.org/info/rfc7950>.
[RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
<https://www.rfc-editor.org/info/rfc8040>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams",
BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018,
<https://www.rfc-editor.org/info/rfc8340>.
[RFC8341] Bierman, A. and M. Bjorklund, "Network Configuration
Access Control Model", STD 91, RFC 8341,
DOI 10.17487/RFC8341, March 2018,
<https://www.rfc-editor.org/info/rfc8341>.
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[RFC8342] Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,
and R. Wilton, "Network Management Datastore Architecture
(NMDA)", RFC 8342, DOI 10.17487/RFC8342, March 2018,
<https://www.rfc-editor.org/info/rfc8342>.
[RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/info/rfc8446>.
[RFC8640] Voit, E., Clemm, A., Gonzalez Prieto, A., Nilsen-Nygaard,
E., and A. Tripathy, "Dynamic Subscription to YANG Events
and Datastores over NETCONF", RFC 8640,
DOI 10.17487/RFC8640, September 2019,
<https://www.rfc-editor.org/info/rfc8640>.
[RFC8641] Clemm, A. and E. Voit, "Subscription to YANG Notifications
for Datastore Updates", RFC 8641, DOI 10.17487/RFC8641,
September 2019, <https://www.rfc-editor.org/info/rfc8641>.
[RFC8776] Saad, T., Gandhi, R., Liu, X., Beeram, V., and I. Bryskin,
"Common YANG Data Types for Traffic Engineering",
RFC 8776, DOI 10.17487/RFC8776, June 2020,
<https://www.rfc-editor.org/info/rfc8776>.
12.2. Informative References
[I-D.geng-teas-network-slice-mapping]
Geng, X., Dong, J., Pang, R., Han, L., Niwa, T., Jin, J.,
Liu, C., and N. Nageshar, "5G End-to-end Network Slice
Mapping from the view of Transport Network", draft-geng-
teas-network-slice-mapping-03 (work in progress), February
2021.
[I-D.ietf-teas-actn-vn-yang]
Lee, Y., Dhody, D., Ceccarelli, D., Bryskin, I., and B. Y.
Yoon, "A YANG Data Model for VN Operation", draft-ietf-
teas-actn-vn-yang-11 (work in progress), February 2021.
[I-D.ietf-teas-ietf-network-slices]
Farrel, A., Gray, E., Drake, J., Rokui, R., Homma, S.,
Makhijani, K., Contreras, L. M., and J. Tantsura,
"Framework for IETF Network Slices", draft-ietf-teas-ietf-
network-slices-00 (work in progress), April 2021.
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[I-D.liu-teas-transport-network-slice-yang]
Liu, X., Tantsura, J., Bryskin, I., Contreras, L. M., Wu,
Q., Belotti, S., and R. Rokui, "IETF Network Slice YANG
Data Model", draft-liu-teas-transport-network-slice-
yang-02 (work in progress), November 2020.
[RFC8309] Wu, Q., Liu, W., and A. Farrel, "Service Models
Explained", RFC 8309, DOI 10.17487/RFC8309, January 2018,
<https://www.rfc-editor.org/info/rfc8309>.
Appendix A. IETF Network Slice NBI Model Usage Example
The following example describes a simplified service configuration of
two IETF Network slice instances:
o IETF Network Slice 1 on Device1, Device3, and Device4, with any-
to-any connectivity type
o IETF Network Slice 2 on Device2, Device3, with any-to-any
connectivity type
192.0.2.2 VLAN1
+--------+
|Device1 o------/
+--------+ | +------+
+--------+ +------o| A +---------------+
|Device2 o-------/-----o| | |
+--------+ +---+--+ |
198.51.100.2 | |
VLAN2 | +---+--+ 192.0.2.4 VLAN1
| | | +--------+
192.0.2.3 VLAN1 | | C o-----/-----oDevice4 |
+--------+ | +---+--+ +--------+
| o------/ | |
| | | +---+--+ |
| Device3| +------o| B +---------------+
| o-------/-----o| |
+--------+ +------+
198.51.100.3
VLAN2
POST: /restconf/data/ietf-network-slice:ietf-network-slices
Host: example.com
Content-Type: application/yang-data+json
{
"network-slices":{
"network-slice":[
{
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"ns-id":"1",
"ns-description":"slice1",
"ns-connectivity-type":"any-to-any",
"ns-endpoints":{
"ns-endpoint":[
{
"ep-id":"11",
"ep-description":"slice1 ep1 connected to device 1",
"ep-role":"any-to-any-role",
"ns-match-criteria":[
{
"match-type":"ns-vlan-match",
"value":[
{
"index":"1",
"value":"1"
}
]
}
]
},
{
"ep-id":"12",
"ep-description":"slice1 ep2 connected to device 3",
"ep-role":"any-to-any-role",
"ns-match-criteria":[
{
"match-type":"ns-vlan-match",
"value":[
{
"index":"1",
"value":"20"
}
]
}
]
},
{
"ep-id":"13",
"ep-description":"slice1 ep3 connected to device 4",
"ep-role":"any-to-any-role",
"ns-match-criteria":[
{
"match-type":"ns-vlan-match",
"value":[
{
"index":"1",
"value":"1"
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}
]
}
]
}
]
}
},
{
"ns-id":"ns2",
"ns-description":"slice2",
"ns-connectivity-type":"any-to-any",
"ns-endpoints":{
"ns-endpoint":[
{
"ep-id":"21",
"ep-description":"slice2 ep1 connected to device 2",
"ep-role":"any-to-any-role",
"ns-match-criteria":[
{
"match-type":"ns-vlan-match",
"value":[
{
"index":"1",
"value":"2"
}
]
}
]
},
{
"ep-id":"22",
"ep-description":"slice2 ep2 connected to device 3",
"ep-role":"any-to-any-role",
"ns-match-criteria":[
{
"match-type":"ns-vlan-match",
"value":[
{
"index":"1",
"value":"2"
}
]
}
]
}
]
}
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}
]
}
}
Appendix B. Comparison with Other Possible Design choices for IETF
Network Slice NBI
According to the 3.3.1. Northbound Inteface (NBI)
[I-D.ietf-teas-ietf-network-slices], the IETF Network Slice NBI is a
technology-agnostic interface, which is used for a customer to
express requirements for a particular IETF Network Slice. Customers
operate on abstract IETF Network Slices, with details related to
their realization hidden. As classified by [RFC8309], 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.
B.1. ACTN VN Model Augmentation
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
[I-D.ietf-teas-actn-vn-yang] is the abstract customer view of the TE
network. Its YANG structure includes four components:
o 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.
o AP: An AP is a logical identifier used to identify the access link
which is shared between the customer and the IETF scoped Network.
o VN-AP: A VN-AP is a logical binding between an AP and a given VN.
o 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.
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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.
B.2. RFC8345 Augmentation Model
The difference between the IETF Network Slice NBI requirements and
the IETF basic network model is that the IETF Network Slice NBI
requests abstract customer 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
[I-D.liu-teas-transport-network-slice-yang] includes three major
parts:
o Network: a transport network list and an list of nodes contained
in the network
o Link: "links" list and "termination points" list describe how
nodes in a network are connected to each other
o 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.
Appendix C. Appendix B IETF Network Slice Match Criteria
5G is a use case of the IETF Network Slice and 5G End-to-end Network
Slice Mapping from the view of IETF Network
[I-D.geng-teas-network-slice-mapping]
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
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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.
+------------------------------------------------------------+
| 5G E2E network slice orchestrator |
++-----------------------------------------------------+-----+
| | |
| IETF Network Slice NBI |
+---+-------+ | +-----+-----+
| | +------------------+ | |
|RAN Slice | |IETF Network Slice| |Core Slice |
|controller | | controller | | controller|
+----+------+ +-------+----------+ +-----+-----+
| | |
| | |
+---+--+ +------------+----------------+ ++-----+
| | | | | |
| | | | | |
|+----+| | | | |
|| ||NS1-NSE1 | Network Slice 1 | |+----+|
||gNB1|+---------+-----+-----------------------+--------+|UPF1||
|| |+************ / |NS1-NSE3|+----+|
|+----+|NS2-NSE1 | */ | | |
| | /* | | |
|+----+|NS1-NSE2 | / * | | |
|| |+---------- * Network Slice 2 |NS2-NSE3|+----+|
||gNB2|+************************************************+|UPF2||
|| ||NS2-NSE2 | | |+----+|
|+----+| | | |
| | | | | |
| | | | | |
+------+ +----------- -----------------+ +------+
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
"ep-ip" 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.
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Authors' Addresses
Bo Wu
Huawei Technologies
101 Software Avenue, Yuhua District
Nanjing, Jiangsu 210012
China
Email: lana.wubo@huawei.com
Dhruv Dhody
Huawei Technologies
Divyashree Techno Park
Bangalore, Karnataka 560066
India
Email: dhruv.ietf@gmail.com
Reza Rokui
Nokia
Email: reza.rokui@nokia.com
Tarek Saad
Juniper Networks
Email: tsaad@juniper.net
Liuyan Han
China Mobile
Email: hanliuyan@chinamobile.com
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