Internet DRAFT - draft-sfc-sinha-5g-split-bearer-dual-access
draft-sfc-sinha-5g-split-bearer-dual-access
Service Function Chaining Sunil Kumar Sinha
Internet-Draft Infinite Computing Solutions
Intended status: Informational Amardeep Sinha
Expires: December 9, 2018 Reliance Jio Infocomm Limited
Amit Mishra
Varsa Networks
Yogesh Chandeshware
Mavenier
June 10, 2018
5G System Split Bearer for Dual-Access
draft-sfc-sinha-5g-split-bearer-dual-access-00
Abstract
This document attempts the case for new work that needs to be
developed for 5G users to improve faster download and upload of
user's data in a scenario of dual-access outlining the poor radio
coverage issues. This document also outlines the faster user data
mechanisum accompanying dual access capabilities of 5G user device
via split bearer in case of a poor coverage.
Status of This Memo
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This Internet-Draft will expire on December 9, 2018.
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Table of Contents:
1. Introduction...................................................2
2. Conventions and Terminology....................................2
3. User data flow for Dual Connectivity for Dual Access and
problem statement..............................................2
3.1 5G System Architecture.....................................2
3.2 QoS........................................................4
3.3 Dual Connectivity..........................................5
3.4 Problem Statement..........................................5
4. Proposal of Split Bearer for dual access.......................5
5. IANA Considerations............................................7
6. Security Considerations........................................7
7. Privacy Considerations ........................................7
8. Acknowledgements...............................................7
9. References.....................................................7
9.1 Normative References.......................................7
9.2 Informative References.....................................8
Authors' Addresses................................................9
1. Introduction
5G system has been evolved to serve the user in more efficient way of
meeting higher download and upload of user data, 5G Users accessing
the network via wireline and wireless, in addition to this
Residential Gateway RG and IoT support is also defined. Access and
user experience is challenging for poor radio coverage (for both
wi-fi and RAN) and the proposal in this document addresses the
problem of poor coverage on either 3GPP or non-3GPP access with UE in
dual-access mode.
2. Conventions and Terminology
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].
3. User data flow for Dual Connectivity for Dual Access and problem
statement
3.1 5G System Architecture
A simplified 5G System architecture shown in Figure-1 in the case of
UE in non-roaming scenario with RAN access(3GPP).
User data of 5G system is delivered to user from Service or data
network via interface N6 and N3 to UE.
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+-----------------------------+
| +-----------------+ |
| | |N8 |N15
+------+ | | +----+ N13 +-----+ |
| NSSF |---+ | | |AUSF|-------| UDM | |
+------+ | | | +----+ +-----+ |
| | | | | |
N22| | | |N12 |N10 +-----+ N5 +----+
| | | +-+ | | PCF |------| AF |
| | | | | +-----+ +----+
| | | | | |
+-------+ N11 +---+ N7 |
| AMF |------------|SMF|-------+
+-------+ +---+
| |
|N2 |N4
| |
| |
Uu +-----+ N3 +---+ N6 +-------------+
UE--------------| RAN |-------------|UPF|--------| Service N/W |
+-----+ +---+ +-------------+
Figure 1 : Simplified 5G System Architecture for RAN access
For the clarity in the current document proposal, multiple node/
function like UDSF, NRF, and interfaces N9, N14 are not shown.
5G System supporting UE access to the network function and services
via non-3GPP is shown in Figure-2. An example of such access are
like WLAN or Wi-Fi. The N3IWF interface connect UE with 5G core
network via N2 and N3 interface.
+-----------------------------+
| +-----------------+ |
| | |N8 |N15
+------+ | | +----+ N13 +-----+ |
| NSSF |---+ | | |AUSF|-------| UDM | |
+------+ | | | +----+ +-----+ |
| | | | | |
N22| | | |N12 |N10 +-----+ N5 +----+
| | | +-+ | | PCF |------| AF |
| | | | | +-----+ +----+
| | | | | |
+-------+ N11 +---+ N7 |
| AMF |------------|SMF|-------+
+-------+ +---+
| |
|N2 |N4
| |
| |
Y1 +--+ Y2 +-----+ N3 +---+ N6 +-------------+
UE-----|AP|-----|N3IWF|-------------|UPF|--------| Service N/W |
+--+ +-----+ +---+ +-------------+
Figure 2 : Simplified 5G System Architecture for Wi-Fi access
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A complete architectural diagram of 5G System catering to both
access type being supported by UE is shown in Figure 3.
+--------------------------------------------------------+
| +----------------------------+ |
| | +------------------+ | |
| | | | | |
| | | |N8 |N15 |
| | | | | |
| +------+ | | +------+ N13 +---+ | |
| | NSSF |--+ | | | AUSF |-------|UDM| | |
| +------+ | | | +------+ +---+ | |
| | | | | | | |
| | | | | | | |
N3| N22| | | |N12 N10| +---+ N5 +--+ |
| | | | +---+ | |PCF|------|AF| |
| | | | | | +---+ +--+ |
| | | | | | | |
+-----+ +---------+ +-----+ | |
| RAN |------| AMF |-----------| SMF |----+ |
+-----+ N2 +---------+ N11 +-----+ N7 |
| | | |
+--+ Uu | | | |
| |-----+ |N2 |N4 |
|UE| | | |
| |-----+ | | |
+--+ Y1 | +----------+ +---------+ |
| | | |
| | | |
+--------+ N3 +-----+ N6 +-------------+ |
|AP+N3IWF|---------------| UPF |------| Service N/W | |
+--------+ +-----+ +-------------+ |
| |
+-------------------------------+
Figure 3 : Simplified 5G System Architecture for Multi access
3.2 QoS
QFI is defined as Qos Flow ID is a identity to QoS flow in the 5G
system. All data traffic within a PDU session are each labelled or
identified by QFI, implies same QFI labelled data flow will receives
same traffic forwarding treatment like scheduling, priority, etc.
QoS /Data flow is via N3(and N3 and N9) interface, being encapsulated
end-to-end. This flow is controlled by SMF, who provides QoS profile
during session establishment to R(AN) and provide the PDR to the UPF.
Please Note that like 4G system, default QoS flow is applied to each
PDU session and retain till lifetime span of connectivity. In case
of non-3GPP access QFI is delivered to N3IWF entity (or NG-RAN) for
every time User Plane of the PDU session is established, modified or
activated.
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3.3 Dual Connectivity
Dual connectivity (DC) functionality support the network to make use
of additional radio resource to achieve required throughput in
downlink and uplink of user data. This was introduced in 4G system
support 5G data speed by addition of dual connectivity of UE with
eNBs, master eNB and secondary eNB and /or eNodeB in congestion with
gNB. This is achieved by addition of secondary eNodeB to the Master
eNodeB. Master eNB has full control to add, delete and HO(handover)
of eNodeBs as and when needed.[20160157293]
3.4 Problem Statement
Problem statement: Inspite of dual access 5G users radio condition
capabilities degrade on either of the access types and the
associated user experience on that access type becomes a challenge.
4. Proposal of Split Bearer for dual access
The solution proposed in this document to solve the problem of
degrade radio condition on the either of the access type at UE and
bearer offloading to other access-type.
Bearer split among RAN and Wifi referring to Fig-4. Trigger for split
bearer of bearer can originate from other of access type RAN or wifi.
- In the example given in figure-4 there is a degrade in radio
condition at RAN access of user. And at the same time 5G user also
have wi-fi access registered.
- Based on measurement report from UE, gNB (RAN) take decision for
partial Handover. gNB asked for UECapabilitys to check availability
of other access type.
- Taking inputs on UECapabilities response about the availability of
other access type, gNB process for Split bearer with other access
type
- gNB(RAN) triggers split bearer request for Wi-Fi access to AMF
and also includes user data traffic template FILTER.
FILTER:
FILTER is a user data delivery template defined by NG-RAN for the
5G-core UPF to implement and execute, without super imposing on the
PCC rule.
- If offload of complete user data traffic is needed, then FILTER
value MUST be empty/NULL.
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+--+ +-----+ +-----+ +---+ +---+ +---+
|UE| | gNB | |N3IWF| |AMF| |SMF| |UPF|
+--+ +-----+ +-----+ +---+ +---+ +---+
| | | | | |
|<==User Data==>|<==============User Data==============>|
| | | | | |
| Measurement Control | | | |
|<--------------| | | | |
| | | | | |
| Measurement | | | | |
|-------------->| | | | |
| Report | | | | |
| +-------------+ | | | |
| | HO Decision | | | | |
| +-------------+ | | | |
| | | | | |
|UEAccessCapability | | | |
|<--------------| | | | |
| | | | | |
|UE-Wifi Access Report | | | |
|-------------->| | | | |
| | | | | |
| +-------------+ | | | |
| |SPLIT Bearer | | | | |
| |Dual Access | | | | |
| +-------------+ | | | |
| | | | | |
| Split-Bearer Request to Wifi | |
| |------------------->| | |
| | (FILTER) | | | |
| | | | | |
| | +---------------------+ | |
| | |HO procedure to N3IWF| | |
| | | + FILTER | | |
| | +---------------------+ | |
| | | | | |
| | | +-------------------------+
| | | |Bearer Update + FILTER |
| | | +-------------------------+
|<WiFi Connectionprocedure>| | | |
| | | | | |
|<=Split Bearer with Wifi=>|<========Data==============>|
| | | | | |
|<=Split Beare=>|<========Data=========================>|
| with RAN | | | | |
Figure 4 : Bearer Offloading Dual-Connectivity with dual access
- If split of user data traffic is needed, then FILTER SHOULD have
required template according to which partial user data traffic is
split between RAN and Wi-Fi by UPF on N3 interface.
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5. IANA Considerations
None.
6. Security Considerations
Security considerations related to the 5G systems are discussed in
[NGMN]. Due to the request for intrinsic realization of security
such aspects have to be considered by design for architecture and
protocols.
Especially as a joint usage of resources and network functions by
different separate logical network slices (e.g. in terms of virtual
network functions) seems to be inevitable in the framework of 5G the
need for strong security measures in such an environment is a major
challenge.
7. Privacy Considerations
Support of full privacy of the users (customers and tenants / end
service providers) is a basic feature of the next generation trusted
and reliable communications offering system. Such a high degree of
ensured privacy shall be reflected in the proposed architecture and
protocol solutions.
Especially as Identifiers and mapping of locators to them are
addressed some privacy concerns arise. Mobility solutions tend to
expose unique identifiers. A solution inside the mobile network
exposes these identifiers to the network operator, which is not a big
deal since the network operator already has information about the
device's location. In contrast, an IP level solution exposes both
the identifiers and the locations at the IP layer. That means that
web sites, for example, can now track the device's successive
locations by watching the IP address. Solutions such as transporting
the identifiers not as part of the IP header should be considered.
8. Acknowledgements
This work has been partially performed in the framework of the
cooperation Config. Contributions of the project partners are
gratefully acknowledged. The project consortium is not liable for
any use that may be made of any of the information contained therein.
Comments, constructive critisms from Karthik Palaniswamy and
Nagesh V. J. are respectfully acknowledged.
9. References
9.1. Normative References
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[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
9.2. Informative References
[20160157293]
"Method to Provide Dual Connectivity Using LTE Master
eNodeB and Wi-Fi Based Secondary eNodeB", June,2016.
[TS23.228]
"IP Multimedia Subsystem (IMS)", March 2018.
[TR38.801]
"Study on new radio access technology: Radio
access architecture and interfaces", March 2017.
[TR23.793]
"Study on Access Traffic Steering, Switch and Splitting
support in the 5G system architecture.", April 2018.
[TR23.793]
"Study on Access Traffic Steering, Switch and Splitting
support in the 5G system architecture.", April 2018.
[ETSI GR NGP 004]
"Next Generation Protocol (NGP):Evolved Architecture for
mobility using. Identity Oriented Networks.",January 2018
[ETSI GR NGP 001]
"Next Generation Protocol (NGP); Scenario Definitions".
,May 2017
[TS23.501]
"3GPP TS23.501, System Architecture for the 5G System
(Release 15)", March 2018.
[TS23.502]
"3Procedures for the 5G System", March 2018.
[TS36.300]
"3GPP TS36.300, Evolved Universal Terrestrial Radio Access
(E-UTRA) and Evolved Universal Terrestrial Radio Access
Network (E-UTRAN); Overall description", March 2018.
[NGMN]
NGMN Alliance, "NGMN White Paper", February 2015.
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Authors' Addresses
Sunil Kumar Sinha
FF-01, Rainbow Residency,
Green Glan layout,
Bellandur, Bangalore
Karnataka, India
Email: sunilkumarsinha9@gmail.com
Amardeep Sinha
C-1003, Yashodeep Heights,
Sec-29C, Airoli,
Navi-Mumbai, Maharashtra, India
Email: sinha.amardeep@gmail.com
Amit Mishra
Flat No: 208, 16th Block,
Sun City Appartments,
Iblur Junction, Sarjapur Signal,
Bengaluru, India
Email: amit.j.mishra@gmail.com
Yogesh Chandeshware
Shasi Nivas, 1st Street , F main,
Vijaya Vank Colony Extn,
Banaswadi, Bangalore
Karnataka,
India
Email: yogeshjc017@gmail.com
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