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Versions: 00 01 02 03 04 draft-irtf-icnrg-5gc-icn

ICNRG                                                       R. Ravindran
Internet-Draft                                                    Huawei
Intended status: Informational                                 P. Suthar
Expires: May 2, 2018                                               Cisco
                                                                 G. Wang
                                                                  Huawei
                                                        October 29, 2017


          Enabling ICN in 3GPP's 5G NextGen Core Architecture
                      draft-ravi-icnrg-5gc-icn-00

Abstract

   The proposed 3GPP's 5G core nextgen architecture (5GC) offers
   flexibility to introduce new user and control plane function within
   the context of network slicing that allows greater flexibility to
   handle heterogeneous devices and applications.  In this draft, we
   provide a short description of the proposed 5GC, followed by
   extensions to 5GC's control and user plane to support packet data
   unit (PDU) sessions from information-centric networks.  The value of
   enabling ICN in 5GC is discussed using two service scenarios which
   include mobile edge computing and support for seamless mobility for
   ICN sessions.

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
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   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
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   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on May 2, 2018.

Copyright Notice

   Copyright (c) 2017 IETF Trust and the persons identified as the
   document authors.  All rights reserved.





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   This document is subject to BCP 78 and the IETF Trust's Legal
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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  5G NextGen Core Design Principles . . . . . . . . . . . . . .   5
   4.  5G NextGen Core Architecture  . . . . . . . . . . . . . . . .   6
   5.  5GC Architecture with ICN Support . . . . . . . . . . . . . .   8
     5.1.  Control Plane Extensions  . . . . . . . . . . . . . . . .  10
       5.1.1.  Normative Interface Extensions  . . . . . . . . . . .  12
     5.2.  User Plane Extensions . . . . . . . . . . . . . . . . . .  12
       5.2.1.  Normative Interface Extensions  . . . . . . . . . . .  13
   6.  ICN Deployement Use Case Scenarios  . . . . . . . . . . . . .  14
     6.1.  Mobile Edge Computing . . . . . . . . . . . . . . . . . .  14
       6.1.1.  IP-MEC Scenario . . . . . . . . . . . . . . . . . . .  14
       6.1.2.  ICN-MEC Scenario  . . . . . . . . . . . . . . . . . .  15
     6.2.  ICN Session Mobility  . . . . . . . . . . . . . . . . . .  16
   7.  Conclusion  . . . . . . . . . . . . . . . . . . . . . . . . .  18
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  18
   9.  Security Considerations . . . . . . . . . . . . . . . . . . .  18
   10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  18
   11. Informative References  . . . . . . . . . . . . . . . . . . .  18
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  20

1.  Introduction

   The objective of this draft is to propose an architecture to enable
   information-centric networking (ICN) in the proposed 5G Next-
   generation Core network architecture (5GC) by leveraging its
   flexibility to allow new user and associated control plane functions.
   The reference architectural discussions in three core 3GPP
   specifications [TS23.501][TS23.502][TS23.799] form the basis of our
   discussions.  This draft also complements the discussions related to
   various ICN deployment opportunities explored in
   [I-D.rahman-icnrg-deployment-guidelines], where 5G technology is
   considered as one of the promising alternatives.






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   Though ICN is a general networking technology, it would benefit 5G
   particularly from the perspective of mobile edge computing (MEC).
   Following ICN features shall benefit MEC deployments in 5G:

   o  Edge Computing: Multi-access Edge Computing (MEC) is located at
      edge of network and aids several latency sensitive applications
      such as augmented and virtual reality (AR/VR) and ultra reliable
      and low latency class (URLLC) of applications such as autonomous
      vehicles.  Enabling edge computing over an IP converged 5GC comes
      with the challenge of application level reconfiguration required
      to re-initialize a session whenever it is being served by a non-
      optimal service instance.  In contrast, named-based networking, as
      considered by ICN, naturally supports service-centric networking,
      which minimizes network related configuration for applications and
      allows fast resolution for named service instances.

   o  Edge Storage and Caching : The principal entity for ICN is the
      secured content (or named-data) object, which allows location
      independent data replication at strategic storage points in the
      network, or data dissemination through ICN routers by means of
      opportunistic caching.  These features benefit both realtime and
      non-realtime applications, where a set of users share the same
      content, thereby advantageous to both high-bandwidth and/or low-
      latency applications such as Video-on-Demand (VOD), AR/VR or low
      bandwidth IoT applications.

   o  Session Mobility: Existing long-term evolution (LTE) deployments
      handle session mobility using IP anchor points at Packet Data
      Network Gateway (PDN-GW) and service anchor point called Access
      Point Name (APN) functionality hosted in PDN-GW, and uses a tunnel
      between radio edge (eNodeB) and PDN-GW for each mobile device
      attached to network.  This design fails when service instances are
      replicated close to radio access network (RAN) instances,
      requiring new techniques to handle session mobility.  In contrast,
      application-bound identifier and name resolution split principle
      considered for the ICN is shown to handle host mobility quite
      efficiently [mas].

   To summarize the draft, we first discuss 5GC's design principals that
   allows the support of new network architectures.  Then we summarily
   discuss the 5GC proposal, followed by control and user plane
   extensions required to support ICN PDU sessions.  We then discuss
   specific network services enabled using ICN data networks,
   specifically MEC and ICN session mobility with aid from 5GC control
   plane.






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2.  Terminology

   Following are terminologies relevant to this draft:

      5G-NextGen Core (5GC) : Refers to the new 5G core network
      architecture being developed by 3GPP, we specifically refer to the
      architectural discussions in [TS23.501][TS23.502].

      5G-New Radio (5G-NR): This refers to the new radio access
      interface developed to support 5G wireless interface [TS-5GNR].

      User Plane Function (UPF): UPF is the generalized logical data
      plane function with context of the UE PDU session.  UPFs can play
      many role, such as, being an flow classifier (UL-CL) (defined
      next), a PDU session anchoring point, or a branching point.

      Uplink Classifier (UL-CL): This is a functionality supported by an
      UPF that aims at diverting traffic (locally) to local data
      networks based on traffic matching filters applied to the UE
      traffic.

      Packet Data Network (PDN or DN): This refers to service networks
      that belong to the operator or third party offered as a service to
      the UE.

      Unified Data Management (UDM): Manages unified data management for
      wireless, wireline and any other types of subscribers for M2M, IOT
      application etc.  UDM report subscriber related vital information
      e.g. virtual edge region, list of location visits, sessions active
      etc.  UDM work as subscriber anchor point that means OSS/BSS
      systems will have central monitoring/access of the system to get/
      set subscriber information.

      Authentication Server Function (AUSF): Provides mechanism for
      unified authentication for subscribers related to wireless,
      wireline and any other types of subscribers such as M2M and IOT
      applications.  The functions performed by AUSF are similar to HSS
      with additional functionalities to related to 5G.

      Session Management Function (SMF): Perform session management
      functions for attached users equipment (UE) in 5G Core.  SMF can
      thus be formed by leveraging the CUPS (discussed in the next
      section) feature with control plane session management.

      Access Mobility Function (AMF): Perform access mobility management
      for attached user equipment (UE) to the 5G core network.  The
      function includes, network access stratus (NAS) mobility functions
      such as authentication and authorization.



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      Application Function (AF): Helps with influencing the user plane
      routing state in 5GC considering service requirements.

      Network Slicing: This conceptualizes the grouping for a set of
      logical or physical network functions with its own or shared
      control, data and service plane to meet specific service
      requirements.

3.  5G NextGen Core Design Principles

   The 5GC architecture is based on the following design principles that
   allow it to support new service networks like ICN efficiently
   compared to LTE networks:.

   o  Control and User plane split (CUPS): This design principle moves
      away from LTE's vertically integrated control/user plane design
      (i.e., Serving Gateway, S-GW, and Packet Data Network Gateway,
      P-GW) to one espousing an NFV framework with network functions
      separated from the hardware for service-centricity, flexibility
      and programmability.  In doing so, network functions can be
      implemented both physically and virtually, while allowing each to
      be customized and scaled based on their individual requirements,
      also allowing the realization of multi-slice co-existence.  This
      feature also allows the introduction of new user plane functions
      (UPF).  UPFs can play many roles, such as, being an uplink flow
      classifier (UL-CL), a PDU session anchor point, a branching point
      function, or one based on new network architectures like ICN with
      new control functions, or re-using/extending the existing ones to
      manage the new user plane realizations.

   o  Decoupling of RAT and Core Network : Unlike LTE's unified control
      plane for access and the core, 5GC offers control plane separation
      of the RAN from the core network.  This allows the introduction of
      new radio access technologies (RAT) along with slices based on new
      network architectures, offering the ability to map heterogeneous
      RAN flows to arbitrary core network slices based on service
      requirements.

   o  Non-IP PDU Session Support : A PDU session is defined as the
      logical connection between the UE and the data network (DN). 5GC
      offers a scope to support both IP and non-IP PDU (termed as
      "unstructured" payload), and this feature can potentially allow
      the support for ICN PDUs by extending or re-using the existing
      control functions.

   o  Service Centric Design: 5GC's service orchestration and control
      functions, such as naming, addressing, registration/authentication
      and mobility, will utilize cloud based service APIs.  Doing so



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      enables opening up interfaces for authorized service function
      interaction and creating service level extensions to support new
      network architectures.  These APIs include the well accepted Get/
      Response and Pub/Sub approaches, while not precluding the use of
      procedural approach between functional units (where necessary).

4.  5G NextGen Core Architecture

   In this section, for brevity purposes, we restrict the discussions to
   the control and user plane functions relevant to an ICN deployment.
   More exhaustive discussions on the various architecture functions,
   such as registration, connection and subscription management, can be
   found in[TS23.501][TS23.502].


                                   +---------+             +--------+
                        +--------+ | PCF/UDM |    +------+ |  AF-2  |
                        | NSSF   | |         |    | AF-1 | +-----+--+
                        +---+----+ +-----+---+    +--+---+       |
                            |            |           |        +--+--------+
                        +---+------------+-+   +-----+------+ |           |
                        |                  |N11|            | |   SMF-2   |
                        |     AMF          +---+   SMF-1    | |           |
                        |                  |   |            | +---------+-+
                        +--------+-+-------+   +----+-------+           |
                                 | |                |-----------------------------------+
              +------------------+ |                |                   |N4             |N4
           N1 |                    |N2              |N4                 |      +--------+-----------+
              |                    |                |                +---------+        UPF         | N6 +------+
+-------------+-+       +----------+------+     +---+-----------+    |  |      |(PDU Session Anchor)+----+  DN  |
|               |       |                 |     |               | N9 |  |      |                    |    |      |
|     UE        |       |      RAN        | N3  |    UL-CL      +----+  |      +--------------------+    +------+
|               +-------+                 +-----+               |       |
|               |       |                 |     |               +----+  +-----------------+
+---------------+       +-----------------+     +---------------+ N9 |                    |
                                                                     |         +----------+---------+
                                                                     +---------+                    |    +--------+
                                                                               |        UPF         | N6 |  DN    |
                                                                               |(PDU Session Anchor)+----+        |
                                                                               |                    |    +--------+
                                                                               +--------------------+


Figure 1: 5G Next Generation Core Architecture


   In Figure 1, we show one variant of a 5GC architecture from
   [TS23.501], for which the functions of UPF's branching point and PDU



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   session anchoring are used to support inter-connection between a UE
   and the related service or packet data networks (or PDNs) managed by
   the signaling interactions with control plane functions.  In 5GC,
   control plane functions can be categorized as follows:

   o  Common control plane functions that are common to all slices and
      which include the Authentication and Mobility Function (AMF),
      Network Slice and Selection Function (NSSF), Policy Control
      Function (PCF), and Unified Data Management (UDM) among others.

   o  Shared or slice specific control functions, which include the
      Session and Management Function (SMF) and the Application Function
      (AF).

   AMF serves multiple purposes: (i) device authentication and
   authorization; (ii) security and integrity protection to non-access
   stratum (NAS) signaling; (iii) tracking UE registration in the
   operator's network and mobility management functions as the UE moves
   among different RANs, each of which might be using different radio
   access technologies (RAT).

   NSSF handles the selection of a particular slice for the PDU session
   request from the user entity (UE) using the Network Slice Selection
   Assistance Information (NSSAI) parameters provided by the UE and the
   configured user subscription policies in PCF and UDM functions.
   Compared to LTE's evolved packet core (EPC), where PDU session states
   in RAN and core are synchronized with respect to management, 5GC
   decouples this using NSSF by allowing PDU sessions to be defined
   prior to a PDU session request by a UE (for other differences see
   [lteversus5g] ).  This de-coupling allows policy based inter-
   connection of RAN flows with slices provisioned in the core network.

   SMF handles session management functions including IP address
   assignment functionality, policy and service capabilities.
   Furthermore, it manages the data plane state in the user plane
   through PDU session establishment, modification and termination, and
   management of RAN (through the AMF) and UPF states related to a
   particular service or slice.

   In the data plane, UE's PDUs are sent to the RAN using the 5G RAN
   protocol [TS-5GNR].  From the RAN, the PDU's five tuple header
   information (IP source/destination, port, protocol etc.) is used to
   map the flow to an appropriate tunnel from RAN to UPF.  The UPF in
   this case also offers flexibility as a flow classifier and a
   branching point interconnecting PDUs from diverse services (within
   UEs) to their respective DNs.  Though [TS23.501] follows LTE on using
   GTP tunnel from NR to the UPF to carry data PDU and another one for




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   the control messages to serve the control plane functions; there are
   ongoing discussions to arrive upon efficient alternatives to GTP.

5.  5GC Architecture with ICN Support

   In this section, we focus on control and user plane enhancements
   required to enable ICN within 5GC, and identify the interfaces that
   require extensions to support ICN PDU sessions.  Explicit support for
   ICN PDU sessions within access and 5GC networks will enable
   applications to leverage the core ICN features while offering it as a
   service to 5G users.








































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                                                               +------------+
                                                               |     5G     |
                                                               | Services   |
                                                               |   (NEF)    |         +----------------+
                                                               +-------+----+         |      ICN       |
                                                                       |   +----------+    Service     |
                                                                       |   |          |  Orchestrator  |
                                                                       |   |          +-----------+----++
               +-------+  +---------+           Npcf++/Nudm++         ++------+                   |
               | NSSF  |  | PCF/UDM +---------------------------------+ ICN-AF|                   |
               +----+--+  |         |                                 |       |               +---+--------------+
                    |     +--+------+                                 +---+---+               |       ICN        |
                    |        |                                            |            +------+  Service/Network |
                  +-+--------+--+           +---------------+      +------+-------+    |      |    Controller    |
                  |             |   N11++   |               |Naf++ |              +----+      +------------+-----+
                  |   AMF++     +-----------+   SMF++       +------+    ICN-SMF   |                        |
                  |             |           |               |      |              |                        |
                  +------+-+----+           +----+-----+----+      +------------+-+                        |
                         | |                           |                        | NIcn                     |
       +-----------------+ |                           |                        +----------+               |
       |                   |                           |                                   |               |
       |                   +------+                 N4 |                                   |               |
  N1++ |                          |                    |                                   |               |
       |                          | N2                 |                      +------------+-+        +----+-----+
       |                          |                    |           +----------+              |        |          |
       |                          |                    |           |   N9     |   ICN-AP     +--------+  ICN-DN  |
       |                          |              +-----+-----+     |          |   + UPF      |   N6   |          |
+------+--+             +---------+--+           |           |     |          +---+----------+        +----------+
|         |             |RAN         |           |   UL-CL/  +-----+
| ICN-UE  +-------------+            +-----------+ Branching |
|         |             |  +-------+ |    N3     |   Point   +-----+           +------------+
+---------+             |  | UL-CL | |           +-----------+     |           |  Local     |
                        |  +-------+ |                             |    N9     |  ICN-DN    |
                        +------------+                             +-----------+            |
                                                                               +------------+



Figure 2: 5G Next Generation Core Architecture with ICN support


   For an ICN-enabled 5GC network, the assumption is that the UE may
   have applications that can run over ICN or IP, for instance, UE's
   operating system offering applications to operate over ICN [Jacobson]
   or IP-based networking sockets.  There may also be cases where UE is
   exclusively based on ICN.  In either case, we identify an ICN enabled
   UE as ICN-UE.  Different options exist to implement ICN in UE as
   described in [I-D.suthar-icnrg-icn-lte-4g] which is also applicable



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   for 5G UE to enable formal ICN session handling, such as, using a
   transport convergence layer above 5G-NR, through IP address
   assignment from 5GC or using 5GC provision of using unstructured PDU
   session mode during the PDU session establishment process. 5G UE can
   also be non-mobile devices or an IOT device using radio specification
   which can operate based on [TS-5GNR].

   5GC will take advantage of network slicing function to instantiate
   heterogeneous slices, the same framework can be extended to create
   ICN slices as well [Ravindran].  This discussion also borrows ideas
   from[TS23.799], which offers a wide range of architectural
   discussions and proposals on enabling slices and managing multiple
   PDU sessions with local networks (with MEC) and its associated
   architectural support (in the service, control and data planes) and
   procedures within the context of 5GC.

   Figure 2 shows the proposed ICN-enabled 5GC architecture.  In the
   figure, new/modified functional components are identified to
   interconnect an ICN-DN with 5GC.  The interfaces and functions that
   require extensions to enable ICN as a service in 5GC can be
   identified in the figure with a '++' symbol.  We next summarize the
   control, user plane and normative interface extensions that help with
   the formal ICN support.

5.1.  Control Plane Extensions

   To support interconnection between ICN UEs and the appropriate ICN DN
   instances, we require five additional control plane extensions, which
   are discussed as follows.

   o  Authentication and Mobility Function (AMF++) : Applications in the
      UEs have to be authorized to access ICN DNs.  For this purpose, as
      in[TS23.501], operator enables ICN as a service-DN to support ICN
      PDU session flows.  As a network service, ICN-UE should also be
      subscribed to it and this is imposed using the PCF and User Data
      and Management (UDM) functions, which may interface with the ICN
      Application Function (ICN-AF) for policy management of ICN PDU
      sessions.  Hence, if the UE policy profile in the UDM doesn't
      enable this feature, then the ICN applications in the UE will not
      be allowed to connect to ICN DNs.  To enable ICN stack in the UE,
      AMF function has to be modified to understand ICN type UE
      registration request and handle authentication and registration
      requests.  AMF++ will support ICN specific bootstrapping and
      forwarding functions (such as naming and security) to configure
      UE's ICN applications.  With appropriate enhancements, it should
      also support forwarding rules for the name prefixes that bind the
      flows to appropriate 5G-NR logical tunnel or slice interfaces.
      These functions can also be handled by the ICN-AF after setting



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      PDU session state in 5GC.  Here, we are not recommending
      modification of 5G UE attach procedures but use existing attach
      procedures messages to carry ICN capabilities extensions in
      addition to supporting existing IP based services. 5G UE can
      request authentication for attaching to 5GC either in ICN, IP or
      dual-stack (IP and ICN) modes.

   o  Session Management Function (SMF++) : Once a UE is authenticated
      to access ICN service in network, SMF manages to connect UE's ICN
      PDU sessions to the ICN DN.  SMF++ capabilities should be able to
      manage both IP, ICN or dual stack UE with IP and ICN capabilities.
      SMF++ creates appropriate PDU session policies in the UPF, which
      include UL-CL and ICN anchor point (ICN-AP).  For centrally
      delivered services, ICN-AP could also be an IP anchor point for IP
      applications.  If MEC is enabled, these two functions would be
      distributed, as the UL-CL will re-route the flow to a local ICN-
      DN.  SMF++ interfaces with AMF over N11++ to enable ICN specific
      user plane function, which includes IP address configuration and
      associated traffic filter policy to inter-connect UE with the
      appropriate radio slice.  Furthermore, AMF++ sets appropriate
      state in the RAN that directs ICN flows to chosen ICN UL-CL.

   o  ICN Session Management Function (ICN-SMF) : ICN-SMF serves as
      control plane for the ICN state managed in ICN-AP.  This function
      interacts with SMF++ to obtain and also push ICN PDU session
      management information for the creation, modification and deletion
      of ICN PDU sessions in ICN-AP.  For instance, when new ICN slices
      are provisioned by the ICN service orchestrator, ICN-SMF requests
      a new PDU session to the SMF++ that extends to the RAN and UE.
      While SMF++ manages the tunnels to interconnect ICN-AP to UL-CL,
      ICN-SMF creates the appropriate forwarding state in ICN (using the
      forwarding information base or FIB) to enable ICN flows over
      appropriate tunnel interfaces managed by the SMF++.

   o  ICN Application Function (ICN-AF) : ICN-AF represents the
      application controller function that interfaces with ICN-SMF and
      user data management (UDM) function in 5GC.  In addition to
      transferring ICN forwarding rules to ICN-SMF, ICN-AF also
      interfaces with UDM to transfer user profile and subscription
      policies required to map UE's ICN PDU session request to an
      appropriate ICN slice through NSSF.  ICN-AF is an extension of the
      ICN service orchestration function, which can influence both ICN-
      SMF and UPF to steer traffic based on UE (or changing service)
      requirements.  ICN-AP can also interact with the northbound 5G
      operator's service functions, such as network exposure function
      (NEF) that exposes network capabilities, for e.g. location based
      services, that can be used by ICN-AF for proactive ICN PDU session
      and slice management and offer additional capabilities to UE.



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5.1.1.  Normative Interface Extensions

   o  N1++/N11++: This extension enables ICN specific control extensions
      to support ICN programmability at the UE via AMF++, and also
      impose QoS requirements to ICN PDU session in 5GC based on service
      requirements.

   o  NIcn: This extension shall support two functions: (i) control
      plane programmability to enable ICN PDU sessions applicable to 5GC
      to map to name based forwarding rules in ICN-AP; (ii)control plane
      extensions to enable ICN mobility anchoring at ICN-AP, in which
      case it also acts as POA for ICN flows.  Features such as ICN
      mobility as a service can be supported with this extension [mas].

   o  Naf++: This extensions shall support 5GC control functions such as
      (i.e. naming, addressing, registration/authentication and
      mobility) for ICN UE and PDU sessions respectively with
      interaction with the PCF and UDM functions.  The PCF and UDM
      functions interacts with ICN-AF function for service or slice
      specific configuration.

   o  Npcf++/Nudm++: This extension creates an interface to push ICN PDU
      session requirement to PCF and UDM functions, which is enforced
      during ICN application registration, authentication, during ICN
      slice mapping, and provisioning of resources for these PDU
      sessions in the UPFs.

5.2.  User Plane Extensions

   As explained in detail in [TS23.501], UPFs are service agnostic
   functions, hence extensions are not required to operate an ICN-DN.
   The inter-connection of UE to ICN-DN comprises of two segments, one
   from RAN to UL-CL and the other from UL-CL to ICN-AP.  These segments
   use IP tunneling constructs, where the service semantic check at UL-
   CL and ICN-AP is performed using IP's five tuples to determine both
   UL and DL tunnel mappings.  We summarize the relevant UPFs and the
   interfaces for handling ICN PDU sessions as follows.

   o  ICN Anchor Point (ICN-AP): ICN-AP shall host the 5GC PDU sessions
      and offer inter-connection to the ICN-DNs.  It manages multiple
      logical interfaces with ICN capable UE and relays ICN packets to
      the appropriate ICN PDU session instances in the DL.  ICN-AP shall
      be logical service anchor point and it should be capable of
      serving different ICN services.  ICN-AP also manages the mobility
      state of ICN-UE after session is established such as in the case
      of handover or roaming.





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   o  ICN Packet Data Network (ICN-(P)DN) : ICN-DN represents a set of
      ICN nodes used for ICN networking and with heterogeneous service
      resources such as storage and computing points.  An ICN network
      enables both network and application services, with network
      services including caching, mobility, multicast, multi-path
      routing (and possibly network layer computing), and application
      services including network resources (such as cache, storage,
      network state resources) dedicated to the application.  This UPF
      requires service, control and data plane mechanisms to understand
      the application requirements and translate them to control
      signaling to provision the required state in the data plane.

   o  Uplink Classifier (UL-CL) :UL-CL enables classification of flows
      based on source or destination IP address and steers the traffic
      to an appropriate network or service function anchor point.
      Within the current context, with the assumption that ICN-AP is
      identified based on service IP address associated with the UE's
      flows, UL-CL checks the source or destination address to direct
      traffic to an appropriate ICN-AP.  As UL-CL is a logical function,
      it can also reside in RAN, as shown in Figure 2, where traffic
      classification rules can be applied to forward the ICN payload
      towards the next ICN-AP, as an extension classification can also
      be performed over 5G-NR or ICN protocol to determine the next
      logical hop.  For native ICN UE, ICN shall be deployed on layer-2
      MAC, hence there may not be any IP association; for such packet
      flow, new classification schema shall be required.

5.2.1.  Normative Interface Extensions

   o  N3: Though the current architecture supports heterogeneous service
      PDU handling, future extensions can include user plane interface
      extensions to offer explicit support to ICN PDU session traffic,
      for instance, an incremental caching and computing function in RAN
      or UL-CL to aid with content distribution.

   o  N9: Extensions to this interface can consider UPFs to enable
      richer service functions, for instance to aid context processing.
      In addition extensions to enable ICN specific encapsulation to
      piggyback ICN specific attributes such as traffic characteristics
      between the UPF branching point and the ICN-AP.  The intermediate
      nodes between the UL-CL and the ICN-AP can also be other caching
      points.

   o  N6: This interface is established between the ICN-AP and the ICN-
      DN, whose networking elements in this segment can be deployed as
      an overlay or as a native Layer-3 network.





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6.  ICN Deployement Use Case Scenarios

   Here we discuss two relevant network services enabled using ICN in
   5G.

6.1.  Mobile Edge Computing

   We consider here a radio edge service requiring low latency, high
   capacity and strict quality of service.  For the discussion in this
   draft, we analyze connected vehicle scenario, where the car's
   navigation system (CNS) uses data from the edge traffic monitoring
   (TM-E) service instance to offer rich and critical insights on the
   road conditions (such as real-time congestion assisted with media
   feeds).  This is aided using traffic sensing (TS) information
   collected through vehicle-to-vehicle (V2V) communication over
   dedicated short-range communications (DSRC) radio by the TS-E, or
   using road-side sensor units (RSU) from which this information can be
   obtained.  The TS-E instances then push this information to a central
   traffic sensing instance (TS-C).  This information is used by the
   central traffic monitoring service (TM-C) to generate useable
   navigation information, which can then be periodically pushed to or
   pulled by the edge traffic monitoring service (TM-E) to respond to
   requests from vehicle's CNS.  For this scenario, our objective is to
   compare advantages of offering this service over an IP based MEC
   versus one based on ICN.  We can generalize the following discussion
   to other MEC applications as well.

6.1.1.  IP-MEC Scenario

   Considering the above scenario, when a vehicle's networking system
   comes online, it first undergoes an attachment process with the 5G-
   RAN, which includes authentication, IP address assignment and DNS
   discovery.  The attachment process is followed by PDU session
   establishment, which is managed by SMF signaling to UL-CL and the UPF
   instance.  When the CNS application initializes, it assumes this IP
   address as its own ID and tries to discover the closest service
   instance.  Local DNS then resolves the service name to a local MEC
   service instance.  Accordingly, CNS learns the IP service point
   address and uses that to coordinate between traffic sensing and
   monitoring applications.

   CNS is a mission critical application requiring instant actions which
   is accurate and reliable all the time.  Delay of microsecond or non-
   response could result in fatalities.  Following are main challenges
   with the IP-MEC design:

   o  At the CNS level, non-standardization of the naming schema results
      in introducing an application level gateway to adapt the sensing



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      data obtained from DSRC system to IP networks, which becomes
      mandatory if the applications are from different vendors.

   o  As the mobility results in handover between RAN instances,
      service-level or 5GC networking-level mechanisms need to be
      initiated to discover a better TM-E instance, which may affect the
      service continuity and result in session reestablishment that
      introduces additional control/user plane overheads.

   o  Data confidentiality among multiple CNS attached 5G RAN,
      authentication and privacy control are offered through an SSL/TLS
      mechanism over the transport channel, which has to be re-
      established whenever the network layer attributes are reset.

6.1.2.  ICN-MEC Scenario

   If the CNS application is developed over ICN either natively or as an
   overlay over IP, ICN shall allows the same named data logic to
   operate over heterogeneous interfaces (such as DSRC radio, and IP
   transport-over-5G, unlicensed radio over WiFi etc. link), thereby
   avoiding the need for application layer adaptations.

   We can list the advantages of using ICN-based MEC as follows:

   o  As vehicles within a single road segment are likely to seek the
      same data, ICN-based MEC allows to leverage opportunistic caching
      and storage enabled at ICN-AP, thereby avoiding service level
      unicast transmissions.

   o  Processed and stored traffic data can be easily contextualized to
      different user requirements.

   o  Appropriate mobility handling functions can be used depending on
      mobility type (as consumer or producer), specifically, when an
      ICN-UE moves from one RAN instance to another, the next IP hop,
      which identifies the ICN-AP function, has to be re-discovered.
      Unlike the IP-MEC scenario, this association is not exposed to the
      applications.  As discussed earlier, control plane extensions to
      AMF and SMF can enable re-programmability of the ICN layer in the
      vehicle to direct it towards a new ICN-AP, or to remain with the
      same ICN-AP, based on optimization requirements.

   o  As ICN offers content-based security, produced content can be
      consumed while authenticating it at the same time (i.e., allowing
      any data produced to diffuse to its point of use through named
      data networking).





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6.2.  ICN Session Mobility

   Mobility scenario assumes a general ICN-UE handover from S-RAN to
   T-RAN, where each of them is served by different UPFs, i.e., UL-CL-1
   and UL-CL-2.  We also assume that UL-CL-1 and UL-CL-2 use different
   ICN-APs as gateways, referred to as ICN-AP-1 and ICN-AP-2.  From an
   ICN perspective, we discuss here the producer mobility case, which
   can be handled in multiple ways, one of which is proposed in
   [mas].However, the details of the ICN mobility solution are
   orthogonal to this discussion.  Here, ICN-UE refers to an application
   producer (e.g., video conferencing application, from which ICN
   consumers request real-time content.  Here we also assume the absence
   of any direct physical interface, Xn, between the two RANs.  The
   current scenario follows the handover procedures discussed in
   [TS23.502], with focus here on integrating it with an ICN-AP and ICN-
   DN, where mobility state of the ICN sessions are handled.

   The overall signaling overhead to handle seamless mobility also
   depends on the deployment models discussed in Section 4.  Here we
   consider the case when RAN, UL-CL and ICN-AP are physically disjoint;
   however in the case where RAN and UL-CL are co-located then a part of
   the signaling to manage the tunnel state between the RAN and UL-CL is
   localized, which then improves the overall signaling efficiency.
   This can be further extended to the case when ICN-APs are co-located
   with the RAN and UL-CL, leading to further simplification of the
   mobility signaling.

   Next, we discuss the high-level steps involved during handover.

   o  Step 1: When the ICN-UE decides to handover from S-RAN to T-RAN,
      ICN-UE signals the S-RAN with a handover-request indicating the
      new T-RAN it is willing to connect.  This message includes the
      affected PDU session IDs from the 5GC perspective, along with the
      ICN names that require mobility support.

   o  Step 2: S-RAN then signals the AMF serving the ICN-UE about the
      handover request.  The request includes the T-RAN details, along
      with the affected ICN PDU sessions.

   o  Step 3: Here, when SMF receives the ICN-UE's and the T-RAN
      information, it identifies UL-CL-2 as the better candidate to
      handle the ICN PDU sessions to T-RAN.  In addition, it also
      identifies ICN-AP-2 as the appropriate gateway for the affected
      ICN PDU sessions.

   o  Step 4: SMF signals the details of the affected PDU sessions along
      with the traffic filter rules to switch the UL traffic from UL-
      CL-2 to ICN-AP-2 and DL flows from UL-CL-2 to T-RAN.



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   o  Step 5: SMF then signals ICN-SMF about the PDU session mobility
      change along with the information on UL-CL-2 for it to provision
      the tunnel between ICN-AP-2 and UL-CL-2.

   o  Step 6: Based on the signaling received on the ICN PDU session,
      ICN-SMF identifies the affected gateways, i.e., ICN-AP-1 and ICN-
      AP-2: (i) ICN-SMF signals ICN-AP-2 about the affected PDU session
      information to update its DL tunnel information to UL-CL-2.  Then,
      based on the ICN mobility solution, appropriate ICN mobility state
      to switch the future incoming Interests from ICN-AP-1 to UL-CL-2;
      (ii) ICN-SMF also signals ICN-AP-1 with the new forwarding
      label[mas] to forward the incoming Interest traffic to ICN-AP-2.
      This immediately causes the new Interest payload for the ICN-UE to
      be send to the new ICN gateway in a proactive manner.

   o  Step 7: ICN-SMF then acknowledges SMF about the successful
      mobility update.  Upon this, the SMF then acknowledges AMF about
      the state changes related to mobility request along with the
      tunnel information that is required to inter-connect T-RAN with
      UL-CL-2.

   o  Step 8: AMF then updates the T-RAN PDU session state in order to
      tunnel ICN-UE's PDU sessions from T-RAN to UL-CL-2.  This is
      followed by initiating the RAN resource management functions to
      reserve appropriate resources to handle the new PDU session
      traffic from the ICN-UE.

   o  Step 9: AMF then signals the handover-ack message to the UE,
      signaling it to handover to the T-RAN.

   o  Step 10: UE then issues a handover-confirm message to T-RAN.  At
      this point, all the states along the new path comprising the
      T-RAN, UL-CL-2 and ICN-AP-2 is set to handle UL-DL traffic between
      the ICN-UE and the ICN-DN.

   o  Step 11: T-RAN then signals the AMF on its successful connection
      to the ICN-UE.  AMF then signals S-RAN to remove the allocated
      resources to the PDU session from the RAN and the tunnel state
      between S-RAN and UL-CL-1.

   o  Step 12: AMF then signals SMF about the successful handover, upon
      which SMF removes the tunnel states from UL-CL-1.  SMF then
      signals the ICN-SMF, which then removes the ICN mobility state
      related to the PDU session from ICN-AP-1.  Also at this point,
      ICN-SMF can signal the ICN-NRS (directly or through ICN-AP-2) to
      update the UE-ID resolution information, which now points to ICN-
      AP-2 [mas].




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   Note that, inter-RAN handover mapping to the same UL-CL represents a
   special case of the above scenario.

7.  Conclusion

   In this draft, we explore the feasibility of realizing future
   networking architectures like ICN within the proposed 3GPP's 5GC
   architecture.  Towards this, we summarized the design principles that
   offer 5GC the flexibility to enable new network architectures.  We
   then discuss 5GC architecture along with the user/control plane
   extensions required to handle ICN PDU sessions formally.  We then
   apply the proposed architecture to two relevant services that ICN
   networks can enable: first, mobile edge computing over ICN versus the
   traditional IP approach considering a connected car scenario, and
   argue based on architectural benefits; second, handling ICN PDU
   session mobility in ICN-DN rather than using IP anchor points, with
   minimal support from 5GC.

8.  IANA Considerations

   This document requests no IANA actions.

9.  Security Considerations

   This draft proposes extensions to support ICN in 5G's next generation
   core architecture.  ICN being name based networking opens up new
   security and privacy considerations which have to be studied in the
   context of 5GC.  This is in addition to other security considerations
   of 5GC for IP or non-IP based services considered in [TS33.899].

10.  Acknowledgments

   ...

11.  Informative References

   [I-D.rahman-icnrg-deployment-guidelines]
              Rahman, A., Trossen, D., Kutscher, D., and R. Ravindran,
              "Deployment Considerations for Information-Centric
              Networking (ICN)", draft-rahman-icnrg-deployment-
              guidelines-04 (work in progress), October 2017.

   [I-D.suthar-icnrg-icn-lte-4g]
              suthar, P., Stolic, M., Jangam, A., and D. Trossen,
              "Native Deployment of ICN in LTE, 4G Mobile Networks",
              draft-suthar-icnrg-icn-lte-4g-03 (work in progress),
              September 2017.




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   [IEEE_Communications]
              Trossen, D. and G. Parisis, "Designing and Realizing an
              Information-Centric Internet", Information-Centric
              Networking, IEEE Communications Magazine Special Issue,
              2012.

   [Jacobson]
              Jacobson, V. and et al., "Networking Named Content",
              Proceedings of ACM Context, , 2009.

   [lteversus5g]
              Kim, J., Kim, D., and S. Choi, "3GPP SA2 architecture and
              functions for 5G mobile communication system.", ICT
              Express 2017, 2017.

   [mas]      Azgin, A., Ravidran, R., Chakraborti, A., and G. Wang,
              "Seamless Producer Mobility as a Service in Information
              Centric Networks.", 5G/ICN Workshop, ACM ICN Sigcomm 2016,
              2016.

   [Ravindran]
              Ravindran, R., Chakraborti, A., Amin, S., Azgin, A., and
              G. Wang, "5G-ICN : Delivering ICN Services over 5G using
              Network Slicing", IEEE Communication Magazine, May, 2016.

   [RFC7927]  Kutscher, D., Ed., Eum, S., Pentikousis, K., Psaras, I.,
              Corujo, D., Saucez, D., Schmidt, T., and M. Waehlisch,
              "Information-Centric Networking (ICN) Research
              Challenges", RFC 7927, DOI 10.17487/RFC7927, July 2016,
              <https://www.rfc-editor.org/info/rfc7927>.

   [TS-5GNR]  3GPP-38-xxx, "Technical Specification series on 5G-NR
              (Rel.15)", 3GPP , 2017.

   [TS23.501]
              3gpp-23.501, "Technical Specification Group Services and
              System Aspects; System Architecture for the 5G System
              (Rel.15)", 3GPP , 2017.

   [TS23.502]
              3gpp-23.502, "Technical Specification Group Services and
              System Aspects; Procedures for the 5G System(Rel. 15)",
              3GPP , 2017.








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   [TS23.799]
              3gpp-23.799, "3rd Generation Partnership Project;
              Technical Specification Group Services and System Aspects;
              Study on Architecture for Next Generation System (Rel.
              14)", 3GPP , 2017.

   [TS33.899]
              3gpp-33.899, "Study on the security aspects of the next
              generation system", 3GPP , 2017.

   [VSER]     Ravindran, R., Liu, X., Chakraborti, A., Zhang, X., and G.
              Wang, "Towards software defined ICN based edge-cloud
              services", CloudNetworking(CloudNet), IEEE Internation
              Conference on, IEEE Internation Conference on
              CloudNetworking(CloudNet), 2013.

Authors' Addresses

   Ravi Ravindran
   Huawei Research Center
   2330 Central Expressway
   Santa Clara  95050
   USA

   Email: ravi.ravindran@huawei.com
   URI:   http://www.Huawei.com/


   Prakash Suthar
   Cisco Systems
   9501 Technology Blvd.
   Rosemont  50618
   USA

   Email: psuthar@cisco.com
   URI:   http://www.cisco.com/


   Guoqiang Wang
   Huawei Research Center
   2330 Central Expressway
   Santa Clara, CA  95050
   USA

   Email: gq.wang@huawei.com






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