5G End-to-end Network Slice Mapping from the view of Transport Network
draft-geng-teas-network-slice-mapping-04
The information below is for an old version of the document.
| Document | Type |
This is an older version of an Internet-Draft whose latest revision state is "Replaced".
|
|
|---|---|---|---|
| Authors | Xuesong Geng , Jie Dong , Ran Pang , Liuyan Han , Reza Rokui , Tomonobu Niwa , Jaewhan Jin , Chang Liu , Nikesh Nageshar | ||
| Last updated | 2021-10-25 | ||
| Replaced by | draft-gcdrb-teas-5g-network-slice-application | ||
| RFC stream | (None) | ||
| Formats | |||
| Stream | Stream state | (No stream defined) | |
| Consensus boilerplate | Unknown | ||
| RFC Editor Note | (None) | ||
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| Send notices to | (None) |
draft-geng-teas-network-slice-mapping-04
Network Working Group X. Geng
Internet-Draft J. Dong
Intended status: Informational Huawei Technologies
Expires: 28 April 2022 R. Pang
China Unicom
L. Han
China Mobile
R. Rokui
Nokia
T. Niwa
Individual
J. Jin
LG U+
C. Liu
China Unicom
N. Nageshar
Individual
25 October 2021
5G End-to-end Network Slice Mapping from the view of Transport Network
draft-geng-teas-network-slice-mapping-04
Abstract
Network Slicing is one of the core features in 5G. End-to-end
network slice consists of 3 major types of network segments: Access
Network (AN), Mobile Core Network (CN) and Transport Network (TN).
This draft describes the procedure of mapping 5G end-to-end network
slice to transport network slice defined in IETF. This draft also
intends to expose some gaps in the existing network management plane
and data plane technologies to support inter-domain network slice
mapping. Further work may require collaboration between IETF and
3GPP (or other standard organizations). Data model specification,
signaling protocol extension and new encapsulation definition are out
of the scope of this draft.
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on 28 April 2022.
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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/
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Please review these documents carefully, as they describe your rights
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminologies . . . . . . . . . . . . . . . . . . . . . . . . 3
3. 5G End-to-End Network Slice Identification . . . . . . . . . 4
4. Network Slice Mapping Structure . . . . . . . . . . . . . . . 5
5. Network Slice Mapping Procedure . . . . . . . . . . . . . . . 8
5.1. Network Slice Mapping in Management Plane . . . . . . . . 9
5.2. Network Slice Mapping in Control Plane . . . . . . . . . 10
5.3. Network Slice Mapping in Data Plane . . . . . . . . . . . 10
5.3.1. Data Plane Mapping Considerations . . . . . . . . . . 10
5.3.2. Data Plane Mapping Options . . . . . . . . . . . . . 11
6. Network Slice Mapping Summary . . . . . . . . . . . . . . . . 15
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16
8. Security Considerations . . . . . . . . . . . . . . . . . . . 16
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 16
10. Normative References . . . . . . . . . . . . . . . . . . . . 16
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 18
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1. Introduction
Driven by the new applications of 5G, the concept of network slicing
is defined to provide a logical network with specific capabilities
and characteristics. Network slice contains a set of network
functions and allocated resources(e.g. computation, storage and
network resources). According to [TS28530], a 5G end-to-end network
slice is composed of three major types network segments: Radio Access
Network (RAN), Transport Network (TN) and Mobile Core Network (CN).
Transport network is supposed to provide the required connectivity
between AN and CN, with specific performance commitment. For each
end-to-end network slice, the topology and performance requirement
for transport network can be very different, which requests transport
network to have the capability of supporting multiple different
transport network slices.
The concept of IETF network slice is discussed in
[I-D.ietf-teas-ietf-network-slices]. In summary, an IETF Network
Slice is a logical network topology connecting a number of endpoints
using a set of shared or dedicated network resources that are used to
satisfy specific Service Level Objectives SLOs) and Service Level
Expectations (SLEs).
The realization of an IETF network slices in Transport network (TN)
could span multiple technology (e.g., IP/MPLS, Optical) and multiple
administrative domains. Depending on the consumer's requirement, an
IETF network slice could be isolated from other concurrent IETF
network slices, in terms of data plane, control plane and management
plane. The procedure for lifecycle of an end-to-end network slice
instance (i.e., creation, deletion, modificatinon, termination etc.)
is defined in [TS28531]. End-to-end network slicing provisioning is
specified in ETSI [ZSM003]. But there is no specifications about how
to map end-to-end network slice to IETF network slices in Transport
Network (TN). This draft describes the procedure of mapping the 5G
end-to-end network slice to IETF network slices in management plane,
control plane and data plane.
2. Terminologies
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
The following terms are used in this document:
NSC: IETF Network Slice Controller
NSI: Network Slice Instance
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NSSI: Network Slice Subnet Instance
S-NSSAI: Single Network Slice Selection Assistance Information
AN: Access Network
RAN: Radio Access Network
TN: Transport Network
CN: Mobile Core Network
DSCP: Differentiated Services Code Point
CSMF: Communication Service Management Function
NSMF: Network Slice Management Function
NSSMF: Network Slice Subnet Management Function
3. 5G End-to-End Network Slice Identification
The following figure illustrates a typical mobile network with three
5G e2e network slices. Each e2e network slice contains AN slice, CN
slice and one or more IETF network Slices. 3GPP identifies each e2e
network slice using an integer called S-NSSAI. In Figure-1 there are
three instances of e2e network slices which are identified by S-NSSAI
01111111, 02222222 and 02333333, respectively. Each instance of e2e
network slice contains AN slice, CN Slice and one or more IETF
network slices. For example, e2e network slice 01111111 has AN Slice
instance 4, CN Slice instance 1 and IETF network slice 6. Note that
3GPP does not cover the IETF network slice. See [I-D.ietf-teas-ietf-
network-slices] for details of IETF network slice.
Note that 3GPP uses the terms NSI and NSSI which are a set of network
function and required resources (e.g. compute, storage and networking
resources) which corresponds to network slice Instance, whereas
S-NSSAI is an integer that identifies the e2e network slice.
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+-----------+ +-----------+ +-----------+
| S-NSSAI | | S-NSSAI | | S-NSSAI |
| 01111111 | | 02222222 | | 03333333 |
+---|-------+ +---|---|---+ +----|------+
| +----------+ | |
V V V V
******* ******** ********
Core * NSSI 1 * * NSSI 2 * * NSSI 3 *
Network ******** ******** ********
\ \ /
\ \ /
+-----+ +-----+ +-----+
Transport | IETF| | IETF| | IETF|
Network | NS 6| | NS 7| | NS 8|
+-----+ +-----+ +-----+
\ \ /
\ \ /
******** ********
Access * NSSI 4 * * NSSI 5 *
Network ******** ********
Figure 1 5G End-to-End Network Slice and its components
4. Network Slice Mapping Structure
Referring to 3GPP TR 28.801, the management of 5G e2e network slices
from 3GPP view is shown in Figure-2(A). Figure-2(B) illustrates the
view of IETF and how it maps to 3GPP network slice management. In
particular, the IETF network slice controller (NSC) is equivalent to
3GPP TN NSSMF and functional block "Consumer" at IETF is equivalent
to 3GPP NSMF.
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+-----------------+
| NSMF |
+-----------------+
+----------| S-NSSAI |----------+
| |(e.g. 011111111) | |
| +-----------------+ |
| | |
V V V
+-------------+ +---------------------+ +-------------+
| AN NSSMF | | IETF NSC | | CN NSSMF |
+-------------+ +---------------------+ +-------------+
| AN Slice | | IETF Network Slice | | CN Slice |
| Identifier | | Identifier | | Identifier |
| (e.g., 4) | | (e.g., 6) | | (e.g., 1) | Management
+-------------+ +---------------------+ +-------------+ Plane
| | | | -----------------
| | | |
V V V V -----------------
/\ +-----+ +-----+ +-------+ Data
/AN\ -----| PE |-----...-----| PE |----| CN | Plane
/____\ +-----+ +-----+ +-------+
Note: Refer to Figure-1 for S-NSSAI 01111111, AN, CN and IETF networks slices 4,6 and 1
Figure-2 Relation between IETF and 3GPP Network Slice management
The following figure shows the necessary elements for mapping end-to-
end network slice into IETF network slices.
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+---------------------+
| CSMF |
+----------|----------+
| +------------------------+
+---------------------+ | 5G E2E Network Slice |
| NSMF | | Orchestrator |
+---------------------+ +------------------------+
/ | \ |
/ | \ NSC NBI |
/ | \ |
+---------++---------++---------+ +------------------------+
| AN || TN || CN | | IETF Network Slice |
| NSSMF || NSSMF || NSSMF | | Controller (NSC) |
| || || | +------------------------+
+---------++---------++---------+ NSC SBI |
| | | |
| | | +------------------------+
| | | | Network Controllers |
| | | +------------------------+
| | | |
| | | |
****** ****** ****** ******
* 5G * * IETF * * 5G * * IETF *
* RAN * * Network* * Core * * Network*
* * * * * * * *
****** ****** ****** ******
Figure-3 5G E2E Network Slice Mapping Structure
The following network slice related identifiers in management plane,
control plane and data(user) plane play an important role in end-to-
end network slice mapping.
* Single Network Slice Selection Assistance Information(S-NSSAI):
The end-to-end network slice identifier, which is defined in
[TS23501]; S-NSSAI is used during 3GPP network slice signalling
process.
* IETF Network Slice Identifier: An identifier allocated by IETF
Neetwork Slice Controller (NSC) in management plane. In data
plane, IETF Network Slice Identifier may be instantiated with
existing data plane identifiers and doesn't necessarily require
new encapsulation.
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* IETF Network Slice Interworking Identifier: Data-plane network
slice identifier which is used for mapping the end-to-end network
slice traffic to specific IETF network slice. The IETF Network
Slice Interworking Identifier is a new concept introduced by this
draft, which may be instantiated with existing data plane
identifiers and doesn't necessarily require new encapsulation.
The relationship between these identifiers are specifies in the
following sections.
5. Network Slice Mapping Procedure
This section provides a general procedure of network slice mapping:
1. NSMF receives the request from CSMF for allocation of a network
slice instance with certain characteristics.
2. Based on the service requirement , NSMF acquires requirements for
the end-to-end network slice instance , which is defined in Service
Profile([TS28541] section 6.3.3).
3. Based on Service Profile, NSMF identified the network function
and the required resources in AN, CN and TN networks. It also
assigns the unique ID S-NSSAI.
4. NSMF sends a request to AN NSSMF for creation of AN Slice.
5. NSMF sends a request to CN NSSMF for creation of CN Slice.
6. NSMF sends a request to IETF Network Slice Controller (NSC) for
creation of IETF Network Slice. The request contains such attribute
such as endpoints, required SLA/SLO along with other IETF network
slice attributes. It also cotains mapping informatin for IETF
Network Slice Interworking Identifier.
7. NSC realizes the IETF network slice which satisfies the
requirement of IETF network slice between the specified endpoints
(AN/ CN edge nodes). It assigns sliceID and send it to NSMF.
8. NSMF has the mapping relationship between S-NSSAI and IETF
Network Slice ID;
9. When the User Equipment (UE) appears, and during the 5G
signalling, it requests to be connected to specific e2e network slice
identified by S-NASSI. Then a GTP tunnel (which is UDP/IP) will be
created.
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10. UE starts sending traffic in context of e2e network slice for
specific S-NASSI.
11. In context of GTP tunnel, the AN edge nodes encapsulates the
packet with sliceIID according to the selected S-NSSAI ans send it to
the transport network.
12. The transport network edge node receives the IP packet and
parses the sliceIID from the packet and maps the packet to the
corresponding IETF network slice. It may encapsulate packet with
sliceID if needed (for example for enforcing QoS in transport
network).
5.1. Network Slice Mapping in Management Plane
The transport network management Plane maintains the interface
between NSMF and TN NSSMF, which 1) guarantees that IETF network
slice could connect the AN and CN with specified characteristics that
satisfy the requirements of communication; 2) builds up the mapping
relationship between NSI identifier and TN NSSI identifier; 3)
maintains the end-to-end slice relevant functions;
Service Profile defined in[TS28541] represents the requirement of
end-to-end network slice instance in 5G network. Parameters defined
in Service Profile include Latency, resource sharing level,
availability and so on. How to decompose the end-to-end requirement
to the transport network requirement is one of the key issues in
Network slice requirement mapping. GSMA(Global System for Mobile
Communications Association) defines the [GST] to indicate the network
slice requirement from the view of service provider.
[I-D.contreras-teas-slice-nbi] analysis the parameters of GST and
categorize the parameters into three classes, including the
attributes with direct impact on the IETF network slice definition.
It is a good start for selecting the transport network relevant
parameters in order to define Network Slice Profile for Transport
Network. Network slice requirement parameters are also necessary for
the definition of transport network northbound interface.
Inside the TN NSSMF, it is supposed to maintain the attributes of the
IETF network slice. If the attributes of an existing TN NSSI could
satisfy the requirement from TN Network Slice Profile, the existing
TN NSSI could be selected and the mapping is finished If there is no
existing TN NSSI which could satisfy the requirement, a new TN NSSI
is supposed to be created by the NSSMF with new attributes.
TN NSSI resource reservation should be considered to avoid over
allocation from multiple requests from NSMF (but the detailed
mechanism should be out of scope in the draft)
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TN NSSMF sends the selected or newly allocated TN NSSI identifier to
NSMF. The mapping relationship between NSI identifier and TN NSSI
identifier is maintained in both NSMF and TN NSSMF.
YANG data model for the Transport Slice NBI, which could be used by a
higher level system which is the Transport slice consumer of a
Transport Slice Controller (TSC) to request, configure, and manage
the components of a transport slices, is defined in
[I-D.wd-teas-transport-slice-yang]. The northbound Interface of IETF
network slice refers to [I-D.wd-teas-ietf-network-slice-nbi-yang].
5.2. Network Slice Mapping in Control Plane
There is no explicit interaction between transport network and AN/CN
in the control plane, but the S-NSSAI defined in [TS23501] is treated
as the end-to-end network slice identifier in the control plane of AN
and CN, which is used in UE registration and PDU session setup. In
this draft, we assume that there is mapping relationship between
S-NSSAI and NSI in the management plane, thus it could be mapped to a
IETF network slice .
Editor's note: The mapping relationship between NSI defined in
[TS23501] and S-NSSAI defined in [TS23501] is still in discussion.
5.3. Network Slice Mapping in Data Plane
If multiple network slices are carried through one physical interface
between AN/CN and TN, IETF Network Slice Interworking ID in the data
plane needs to be introduced. If different network slices are
transported through different physical interfaces, Network Slices
could be distinguished by the interface directly. Thus IETF Network
Slice Interworking ID is not the only option for network slice
mapping, while it may help in introducing new network slices.
5.3.1. Data Plane Mapping Considerations
The mapping relationship between AN or CN network slice identifier
(either S-NSSAI in control plane or NSI/NSSI in management plane) and
IETF Network Slice Interworking ID needs to be maintained in AN/CN
network nodes, and the mapping relationship between IETF Network
Slice Interworking ID and IETF Network Slice is maintained in the
edge node of transport network. When the packet of a uplink flow
goes from AN to TN, the packet is encapsulated based on the IETF
Network Slice Interworking ID; then the encapsulation of IETF Network
Slice Interworking ID is read by the edge node of transport network,
which maps the packet to the corresponding IETF network slice.
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Editor's Note: We have considered to add "Network Instance" defined
in [TS23501]in the draft. However, after the discussion with 3GPP
people, we think the concept of "network instance" is a 'neither
Necessary nor Sufficient Condition' for network slice. Network
Instance could be determined by S-NSSAI, it could also depends on
other information; Network slice could also be allocated without
network instance (in my understanding) And, IETF Network Slice
Interworking ID is not a competitive concept with network
instance.IETF Network Slice Interworking ID is a concept for the data
plane interconnection with transport network, network instance may be
used by AN and CN nodes to associate a network slice with IETF
Network Slice Interworking ID
5.3.2. Data Plane Mapping Options
The following picture shows the end-to-end network slice in data
plane:
+--+ +-----+ +----------------+
|UE|- - - -|(R)AN|---------------------------| UPF |
+--+ +-----+ +----------------+
|<----AN NS---->|<----------TN NS---------->|<----CN NS----->|
The mapping between 3GPP slice and transport slice in user plane
could happens in:
(R)AN: User data goes from (radio) access network to transport
network
UPF: User data goes from core network functions to transport network
Editor's Note: As figure 4.7.1. in [TS28530] describes, TN NS will
not only exist between AN and CN but may also within AN NS and CN NS.
However, here we just show the TN between AN and CN as an example to
avoid unncessary complexity.
The following picture shows the user plane protocol stack in end-to-
end 5G system.
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+-----------+ | | |
|Application+--------------------|------------------|---------------|
+-----------+ | | +-----------+ |
| PDU Layer +--------------------|------------------|-| PDU Layer | |
+-----------+ +-------------+ | +-------------+ | +-----------+ |
| | | ___Relay___ |--|--| ___Relay___ |-|-| | |
| | | \/ GTP-U|--|--|GTP-U\/ GTP-U|-|-| GTP-U | |
| 5G-AN | |5G-AN +------+ | +------+------+ | +-----------+ |
| Protocol | |Protoc|UDP/IP|--|--|UDP/IP|UDP/IP|-|-| UDP/IP | |
| Layers | |Layers+------+ | +------+------+ | +-----------+ |
| | | | L2 |--|--| L2 | L2 |-|-| L2 | |
| | | +------+ | +------+------+ | +-----------+ |
| | | | L1 |--|--| L1 | L1 |-|-| L1 | |
+-----------+ +-------------+ | +-------------+ | +-----------+ |
UE 5G-AN | UPF | UPF |
N3 N9 N6
The following figure shows the typical encapsulation in N3 interface
which could be used to carry the IETF Network Slice Interworking ID
between AN/CN and TN.
+------------------------+
| Application Protocols |
+------------------------+
| IP (User) |
+------------------------+
| GTP |
+------------------------+
| UDP |
+------------------------+
| IP |
+------------------------+
| Ethernet |
+------------------------+
5.3.2.1. Layer 3 and Layer 2 Encapsulations
If the encapsulation above IP layer is not visible to Transport
Network, it is not able to be used for network slice interworking
with transport network. In this case, IP header and Ethernet header
could be considered to provide information of network slice
interworking from AN or CN to TN.
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+------------------------+-----------
| Application Protocols | ^
+------------------------+ |
| IP (User) | Invisible
+------------------------+ for
| GTP | TN
+------------------------+ |
| UDP | V
+------------------------+------------
| IP |
+------------------------+
| Ethernet |
+------------------------+
The following field in IP header and Ethernet header could be
considered :
IP Header:
* DSCP: It is traditionally used for the mapping of QoS identifier
between AN/CN and TN network. Although some values (e.g. The
unassigned code points) may be borrowed for the network slice
interworking, it may cause confusion between QoS mapping and
network slicing mapping.;
* Destination Address: It is possible to allocate different IP
addresses for entities in different network slice, then the
destination IP address could be used as the network slice
interworking identifier. However, it brings additional
requirement to IP address planning. In addition, in some cases
some AN or CN network slices may use duplicated IP addresses.
* Option fields/headers: It requires that both AN and CN nodes can
support the encapsulation and decapsulation of the options.
Ethernet header
* VLAN ID: It is widely used for the interconnection between AN/CN
nodes and the edge nodes of transport network for the access to
different VPNs. One possible problem is that the number of VLAN
ID can be supported by AN nodes is typically limited, which
effects the number of IETF network slices a AN node can attach to.
Another problem is the total amount of VLAN ID (4K) may not
provide a comparable space as the network slice identifiers of
mobile networks.
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Two or more options described above may also be used together as the
IETF Network Slice Interworking ID, while it would make the mapping
relationship more complex to maintain.
In some other case, when AN or CN could support more layer 3
encapsulations, more options are available as follows:
If the AN or CN could support MPLS, the protocol stack could be as
follows:
+------------------------+-----------
| Application Protocols | ^
+------------------------+ |
| IP (User) | Invisible
+------------------------+ for
| GTP | TN
+------------------------+ |
| UDP | V
+------------------------+------------
| MPLS |
+------------------------+
| IP |
+------------------------+
| Ethernet |
+------------------------+
A specified MPLS label could be used to as a IETF Network Slice
Interworking ID.
If the AN or CN could support SRv6, the protocol stack is as follows:
+------------------------+-----------
| Application Protocols | ^
+------------------------+ |
| IP (User) | Invisible
+------------------------+ for
| GTP | TN
+------------------------+ |
| UDP | V
+------------------------+------------
| SRH |
+------------------------+
| IPv6 |
+------------------------+
| Ethernet |
+------------------------+
The following field could be considered to identify a network slice:
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SRH:
* SRv6 functions: AN/CN is supposed to support the new function
extension of SRv6.
* Optional TLV: AN/CN is supposed to support the extension of
optional TLV of SRH.
5.3.2.2. Above Layer 3 Encapsulations
If the encapsulation above IP layer is visible to Transport Network,
it is able to be used to identify a network slice. In this case, UPD
and GTP-U could be considered to provide information of network slice
interworking between AN or CN and TN.
+------------------------+----------
| Application Protocols | |
+------------------------+ Invisible
| IP (User) | for
+------------------------+ TN
| GTP | |
+------------------------+------------
| UDP |
+------------------------+
| IP |
+------------------------+
| Ethernet |
+------------------------+
The following field in UDP header could be considered:
UDP Header:
* UDP Source port: The UDP source port is sometimes used for load
balancing. Using it for network slice mapping would require to
disable the load-balancing behavior.
6. Network Slice Mapping Summary
The following picture shows the mapping relationship between the
network slice identifier in management plane, control plane and user
plane.
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AN/CN | TN
Management +---------+ | +-----------------------+
Plane | NSI |<--------|-->| IETF Network Slice ID |
+---------+ | +-----------------------+
| | |
| | |
Control +-----V-----+ | +----------+----------+
Plane | S-NSSAI | | | |
+-----------+ | | |
| +----V----+ +----V-------+
+----------->| IETF |<--------->| IETF |
Data | Network |<--------->| Network |
Plane | Slice | | Slice |
| InterID | |realization |
+---------+ +------------+
7. IANA Considerations
TBD
Note to RFC Editor: this section may be removed on publication as an
RFC.
8. Security Considerations
TBD
9. Acknowledgements
The authors would like to thank Shunsuke Homma for reviewing the
draft and giving valuable comments.
10. Normative References
[GST] "Generic Network Slice Template",
<https://www.gsma.com/newsroom/all-documents/generic-
network-slice-template-v2-0/>.
[I-D.contreras-teas-slice-nbi]
Contreras, L. M., Homma, S., Ordonez-Lucena, J. A.,
Tantsura, J., and K. Szarkowicz, "IETF Network Slice Use
Cases and Attributes for Northbound Interface of IETF
Network Slice Controllers", Work in Progress, Internet-
Draft, draft-contreras-teas-slice-nbi-05, 12 July 2021,
<https://www.ietf.org/archive/id/draft-contreras-teas-
slice-nbi-05.txt>.
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[I-D.ietf-teas-ietf-network-slice-definition]
Rokui, R., Homma, S., Makhijani, K., Contreras, L. M., and
J. Tantsura, "Definition of IETF Network Slices", Work in
Progress, Internet-Draft, draft-ietf-teas-ietf-network-
slice-definition-01, 22 February 2021,
<https://www.ietf.org/archive/id/draft-ietf-teas-ietf-
network-slice-definition-01.txt>.
[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", Work in Progress,
Internet-Draft, draft-ietf-teas-ietf-network-slices-04, 23
August 2021, <https://www.ietf.org/archive/id/draft-ietf-
teas-ietf-network-slices-04.txt>.
[I-D.wd-teas-ietf-network-slice-nbi-yang]
Wu, B., Dhody, D., Rokui, R., Saad, T., Han, L., and L. M.
Contreras, "IETF Network Slice Service YANG Model", Work
in Progress, Internet-Draft, draft-wd-teas-ietf-network-
slice-nbi-yang-05, 26 September 2021,
<https://www.ietf.org/archive/id/draft-wd-teas-ietf-
network-slice-nbi-yang-05.txt>.
[I-D.wd-teas-transport-slice-yang]
Wu, B., Dhody, D., Han, L., and R. Rokui, "A Yang Data
Model for Transport Slice NBI", Work in Progress,
Internet-Draft, draft-wd-teas-transport-slice-yang-02, 12
July 2020, <https://www.ietf.org/archive/id/draft-wd-teas-
transport-slice-yang-02.txt>.
[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>.
[TS23501] "3GPP TS23.501",
<https://portal.3gpp.org/desktopmodules/Specifications/
SpecificationDetails.aspx?specificationId=3144>.
[TS28530] "3GPP TS28.530",
<https://portal.3gpp.org/desktopmodules/Specifications/
SpecificationDetails.aspx?specificationId=3273>.
[TS28531] "3GPP TS28.531",
<https://portal.3gpp.org/desktopmodules/Specifications/
SpecificationDetails.aspx?specificationId=3274>.
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[TS28541] "3GPP TS 28.541",
<https://portal.3gpp.org/desktopmodules/Specifications/
SpecificationDetails.aspx?specificationId=3400>.
[ZSM003] "ETSI ZSM003",
<https://portal.3gpp.org/desktopmodules/Specifications/
SpecificationDetails.aspx?specificationId=3144>.
Authors' Addresses
Xuesong Geng
Huawei Technologies
Email: gengxuesong@huawei.com
Jie Dong
Huawei Technologies
Email: jie.dong@huawei.com
Ran Pang
China Unicom
Email: pangran@chinaunicom.cn
Liuyan Han
China Mobile
Email: hanliuyan@chinamobile.com
Reza Rokui
Nokia
Email: reza.rokui@nokia.com
Tomonobu Niwa
Individual
Email: tomonobu.niwa@gmail.com
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Jaehwan Jin
LG U+
Email: daenamu1@lguplus.co.kr
Chang Liu
China Unicom
Email: liuc131@chinaunicom.cn
Nikesh Nageshar
Individual
Email: nikesh.nageshar@gmail.com
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