Internet DRAFT - draft-sfc-sinha-5g-ims-dual-reg
draft-sfc-sinha-5g-ims-dual-reg
Service Function Chaining Sunil Kumar Sinha
Internet-Draft Infinite Computing Solutions
Intended status: Informational Amardeep Sinha
Expires: December 17, 2018 Reliance Jio Infocomm Limited
Amit Mishra
Varsa Networks
Manish Srivastava
Commscope Networks
June 18, 2018
5G IMS system supporting dual-Registration for Dual-Access
draft-sfc-sinha-5g-ims-dual-reg-00
Abstract
This document attempts the case for new work that need to be
developed for 5G user to improve user reachability outlining the poor
radio coverage issue with respect to voice and video services by IMS
network. This document also outlines dual access capabilities of 5G
user device and user is reachable on each access-type leading to
faster user reachability.
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 December 17, 2018.
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Table of Contents:
1. Introduction...................................................2
2. Conventions and Terminology....................................2
3. Problem Statement..............................................2
4. 5G IMS system supporting dual-Registration for Dual-Access.....2
5. Security Considerations........................................5
6. IANA Considerations............................................5
6.1 IANA Registration of the "dual" Option Tag ................5
7. Privacy Considerations ........................................6
8. Acknowledgements...............................................6
9. References.....................................................6
9.1 Normative References.......................................6
9.2 Informative References.....................................6
Authors' Addresses................................................6
1. Introduction
5G system have been evolved to server 5G Users with dual access
capability at same time. User access to network service for mo-data
and mt-data for voice and video or data services via both access
type is increased if user's registration state for a particular
service is maintained on each access type independently. In this
document, user access to voice and video service is discussed and
proposal made to maintain user registration state for each access
type of a user at P-CSCF.
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 RFC 2119 [RFC2119].
3. Problem Statement
With user registered for a service for only one access type at a
time, then probability of user reachability at the time of service
delivery leads to considerable amount of delay in UE hunting
procedure.
User registered on access type may happen that user goes
out of network coverage at the time of serve being delivered.
Hunting fails thereby trigger user hunting on another access type.
A considerable amount of delay is incurred on this hunting procedure.
This document outlines this problem by proposing a solution of
dual-registration in section-4.
4. 5G IMS system supporting dual-Registration for Dual-Access
A simplified 5G-system architecture with dual access is show in
Figure 1 below.
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+--------------------------------------------------------+
| +----------------------------+ |
| | +------------------+ | |
| | | | | |
| | | |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 1: Simplified 5G-system Architecture for Multi access
UE upon successful attached to 5G-core by either of access type,
3GPP or non-3GPP, received following details
- UE IP-address
- IMS access IP-address (P-CSCF discovery)
Since UE of 5G System is capable of dual access, implies UE can
simultaneously have active connections with both 3GPP and non-3GPP
access at same time. This in turn implies UE is reachable via both
access type at same time.
Let us consider a simple case where the 5G UE device having dual
access capability gets powered-on and both Wifi and RAN network is
available.
- UE first get attached to RAN and send fresh Registration request to
the IMS network. While sending sine Wifi attached procedure was not
completed, hence Fresh REGISTRATION request via RAN access with
have PANI header=E-UTRAN with no optional tag.
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- Upon successful REGISTRATION stores the UE registration data in the
following format in Table :1.
Table :1
+------+------+-------+---------+----------------+------------------+
| PANI | IMSI | IPsec | Call-ID | Register-Timer | P-Associated-URI |
+------+------+-------+---------+----------------+------------------+
- Upon successful Wifi attached procedure was successful, UE also
triggers for FRESH REGISTER request to IMS network. Since RAN
access was active, hence UE MUST send this FRESH REGISTRATION with
PANI header=wlan with option tag=dual, indicating dual
registration.
- The second registration request triggered via another access type,
in this example wifi will be again Un-Protected Registration, i.e.
different call-ID and different IPsec as shown in Table :2
Table 2
+------+------+-------+---------+----------------+------------------+
| PANI | | IPsec | Call-ID | Register-Timer | P-Associated-URI |
+------+ IMSI +-------+---------+----------------+------------------+
| PANI | | IPsec | Call-ID | Register-Timer | P-Associated-URI |
+------+------+-------+---------+----------------+------------------+
- Additional optional tag with name=dual, need to send during
REGISTRATION to the Network. This parameter will be send to the IMS
network along with PANI [RFC7913] header, in the below format
PANI=.......;dual
The Optional tag=dual, initiates the PCSCF to store two entries of a
user's registration data.
- Upon successful dual registration, in the above scenario after
second registration via wifi access, re-fresh register request is
send with change in PANI header value which was sent earlier.
- Register request sent on RAN access again will have optional
tag=dual.
- In case of loss of radio access and non-reachability, a re-register
request will be sent to network via other access type to update the
network registration status.
- For example, dual REGISTERED 5G UE lost connectivity on wifi.
Whether or not UE's initiated de-register request for Wifi access
reached IMS network, a re-register request will be sent on RAN
access with no optional tag=dual on PANI header. This indicated
loss of wifi access type and P-CSCF will mark will update the user
registration status stored locally by erasing of wifi access.
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- For MT (Mobile terminating) call scenario, terminating S-CSCF will
route the INVITE request to the terminating P-CSCF. Terminating
P-CSCF will forward the INVITE request based on current
registration status of access type.
- If UE had IMS registration successful over both access type RAN and
wifi, dual access, indicating UE is reachable over two access type.
Terminating P-CSCF forwards INVITE on both access type like a
parallel forking. SIP response 183 (Session Progress) received
first from either access type will be processed and received on
this access type will be discarded. Henceforth, bearer creation
over access network via diameter AAR/AAA request with PCF function
will be triggered with accepted response of 183 session-progress
access-type.
- If UE had registration successful with only single access-type,
then terminating P-CSCF forward INVITE on registered access type as
a normal procedure.
5. 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.
6. IANA Considerations
This document registers a new option tag based on the IANA
registration process of RFC 3261.
6.1 IANA Registration of the "dual" Option Tag
This specification registers an option tag, dual. The required
information for this registration, as specified in RFC 3261, is:
Name : dual
Description: This "dual" tag is for informing the SIP Register
Server that about UE dual access mode being currently
active.
Usage : "Dual" optional tag to be using with sip header - PANI,
abbreviated as P-asserted Network Info.
Scope : User side- it is supported at UE device
Network side-it is supported at P-CSCF or SBC of IMS
network.
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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 criticisms from Karthik Palaniswamy and
Nagesh V. J. are respectfully acknowledged.
9. References
9.1. 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,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC7913] C. Holmberg., P-Access-Network-Info ABNF Update,
<https://tools.ietf.org/html/rfc7913>.
9.2. Informative References
[TS23.501]
"3GPP TS23.501, System Architecture for the 5G System
(Release 15)", 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.
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[TS23.502]
"3Procedures for the 5G System", March 2018.
[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
[NGMN]
NGMN Alliance, "NGMN White Paper", February 2015.
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, Maharastra
India
Email: sinha.amardeep@gmail.com
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Amit Mishra
Flat No: 208, 16th Block,
Sun City Apartments,
Iblur Junction, Sarjapur Signal,
Bengaluru, India
Email: amit.j.mishra@gmail.com
Manish Srivastava
Gr Sagarnivas,
Central Jail Road,
Bangalore, Karnataka,
India
Email: manishshree92@gmail.com
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