Internet DRAFT - draft-kanugovi-intarea-mams-protocol

draft-kanugovi-intarea-mams-protocol







INTAREA                                                      S. Kanugovi
Internet-Draft                                              S. Vasudevan
Intended status: Standards Track                                   Nokia
Expires: March 31, 2018                                      F. Baboescu
                                                                Broadcom
                                                                  J. Zhu
                                                                   Intel
                                                                 S. Peng
                                                                  Huawei
                                                              J. Mueller
                                                                    AT&T
                                                                  S. Seo
                                                           Korea Telecom
                                                      September 27, 2017


                  Multiple Access Management Services
                draft-kanugovi-intarea-mams-protocol-05

Abstract

   A communication network includes an access network segment that
   delivers data to/from the users and an associated core network
   segment providing connectivity with the application servers.
   Multiconnectivity scenarios are common where an end-user device can
   simultaneously connect to multiple communication networks based on
   different technology implementations and network architectures like
   WiFi, LTE, DSL.  A smart selection and combination of access and core
   network paths that can dynamically adapt to changing network
   conditions can improve quality of experience for a user in such a
   Multiconnectivity scenario and improve overall network utilization
   and efficiency.  This document presents the problem statement and
   proposes solution principles.  It specifies the requirements and
   reference architecture for a multi-access management services
   framework that can be used to flexibly select the best combination of
   access and core network paths for uplink and downlink, as well as the
   flexible usage of uplink and downlink, ensuring better network
   efficiency and enhanced application performance.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.



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   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on March 31, 2018.

Copyright Notice

   Copyright (c) 2017 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
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   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Conventions used in this document . . . . . . . . . . . . . .   3
   2.  Contributing Authors  . . . . . . . . . . . . . . . . . . . .   3
   3.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   4
   5.  Problem Statement . . . . . . . . . . . . . . . . . . . . . .   5
   6.  Solution Principles . . . . . . . . . . . . . . . . . . . . .   6
   7.  Requirements  . . . . . . . . . . . . . . . . . . . . . . . .   6
     7.1.  Access technology agnostic interworking . . . . . . . . .   6
     7.2.  Support common transport deployments  . . . . . . . . . .   6
     7.3.  Independent Access path selection for Uplink and Downlink   6
     7.4.  Core selection independent of uplink and downlink access    7
     7.5.  Adaptive network path selection . . . . . . . . . . . . .   7
     7.6.  Multipath support and Aggregation of access link
           capacities  . . . . . . . . . . . . . . . . . . . . . . .   7
     7.7.  Scalable mechanism based on user plane interworking . . .   7
     7.8.  Separate Control and Data plane functions . . . . . . . .   8
     7.9.  Lossless Path (Connection) Switching  . . . . . . . . . .   8
     7.10. Concatenation and Fragmentation to adapt to MTU
           differences . . . . . . . . . . . . . . . . . . . . . . .   8
     7.11. Configuring network middleboxes based on negotiated
           protocols . . . . . . . . . . . . . . . . . . . . . . . .   8
     7.12. Policy based Optimal path selection . . . . . . . . . . .   8
     7.13. MAMS Control signaling  . . . . . . . . . . . . . . . . .   9
     7.14. Service discovery and reachability  . . . . . . . . . . .   9



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   8.  MAMS Reference Architecture . . . . . . . . . . . . . . . . .   9
   9.  Solution Principles . . . . . . . . . . . . . . . . . . . . .  12
   10. Implementation considerations . . . . . . . . . . . . . . . .  13
   11. Applicability to Multi Access Edge Computing  . . . . . . . .  14
   12. Security Considerations . . . . . . . . . . . . . . . . . . .  14
     12.1.  Data and Control plane security  . . . . . . . . . . . .  14
   13. Contributors  . . . . . . . . . . . . . . . . . . . . . . . .  15
   14. References  . . . . . . . . . . . . . . . . . . . . . . . . .  15
     14.1.  Normative References . . . . . . . . . . . . . . . . . .  15
     14.2.  Informative References . . . . . . . . . . . . . . . . .  15
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  15

1.  Conventions used in this document

   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].

2.  Contributing Authors

   The editors gratefully acknowledge the following additional
   Contributors in alphabetical order: Hannu Flinck/Nokia, Nurit
   Sprecher/Nokia

3.  Introduction

   Multi Access Management Services (MAMS) is a programmable framework
   that provides mechanisms for flexible selection of network paths in a
   multi-access communication environment, based on application needs,
   which can leverage network intelligence and policies to dynamically
   adapt to changing network/link conditions.  The network path
   selection and configuration procedures use the user plane to exchange
   data between the functional elements in the network and the end-user
   device without any impact to the control plane signaling schemes of
   each individual access network.  For example, in a multi-access
   network with LTE and WiFi technologies, existing LTE and existing
   WiFi signaling procedures will be used to setup the LTE and WiFi
   connections, respectively.  The proposed MAMS framework offers the
   capabilities of smart selection and flexible combination of access
   paths and core network paths.  It is a broad programmable framework
   providing functions beyond just sharing network policies, e.g. in
   comparison to ANDSF that provides policies/rules for assisting 3GPP
   devices to discover and select available access networks, that allows
   choosing and configuring user plane protocols and treatment depending
   on needs of the application.

   The document presents the requirements, solution principles and
   functional architecture for the MAMS framework.  MAMS mechanisms are



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   not dependent on any specific network and transport protocols like
   TCP, UDP, GRE, MPTCP etc.  It co-exists and complements the existing
   protocols by providing a way to negotiate and configure the protocols
   based on client and network capabilities.  Further it allows
   exchanges of network state information and leveraging network
   intelligence to optimize the performance of such protocols.

   An important goal for MAMS is to ensure that there is minimal or no
   dependency on the actual access technologies of the participating
   links, beyond the fact that the MAMS functional elements can be
   placed in the user plane.  This allows the scheme to be future proof,
   for addition of new access technologies and for independent
   technology evolution of the existing access and core networks.

4.  Terminology

   "Client": The end-user device supporting connections with multiple
   access nodes, possibly over different access technologies.

   "Multiconnectivity Client": A client with multiple network
   connections.

   "Access network": The segment in the network that delivers user data
   packets to the client via an access link like WiFi airlink, LTE
   airlink, or DSL.

   "Core": The functional element that anchors the client's IP address
   used for communication with applications via the network.

   "User Plane Gateway": The functional element that can intercept and
   route user data packets.

   "Network Connection manager"(NCM): A functional entity in the network
   that oversees distribution of data packets over the multiple
   available access and core network paths.

   "Client Connection Manager" (CCM): A functional entity in the client
   that exchanges MAMS Signaling with the Network Connection Manager and
   configures the multiple network paths for transport of user data.

   "Network Multi Access Data Proxy" (N-MADP): This functional entity in
   the network handles the user data traffic forwarding across multiple
   network paths.  N-MADP is responsible for MAMS related user-plane
   functionalities in the network.

   "Client Multi Access Data Proxy" (C-MADP): This functional entity in
   the client handles the user data traffic forwarding across multiple




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   network paths.  C-MADP is responsible for MAMS related user-plane
   functionalities in the client.

5.  Problem Statement

   Typically, an end-user device has access to multiple communication
   networks based on different technologies, say LTE, WiFi, DSL,
   MuLTEfire, for accessing application services.  Different
   technologies exhibit benefits and limitations in different scenarios.
   For example, WiFi leverages the large spectrum available in
   unlicensed spectrum to deliver high capacities at low cost in
   uncongested scenarios with small user population, but can show
   significant degradation in application performance in congested
   scenarios with large user population.  Another example is LTE
   network, the capacity of which is often constrained by high cost and
   limited availability of the licensed spectrum, but offers predictable
   service even in multi-user scenarios due to controlled scheduling and
   licensed spectrum usage.

   Additionally, the use of a particular access network path is often
   coupled with the use of its associated core network.  For example, in
   an enterprise that has deployed WiFi and LTE communications network,
   enterprise applications, like printers, Corporate Audio and Video
   conferencing, are accessible only via WiFi access connected to the
   enterprise hosted WiFi core, whereas the LTE access can be used to
   get LTE operator core anchored services including access to public
   Internet.

   Application performance in different scenarios, therefore becomes
   dependent on the choice of the communication networks based on
   different technologies (e.g.  WiFi and LTE) due to the tight coupling
   of the access and the core network paths.  Therefore to achieve the
   best possible application performance in a wide range of possible
   scenarios, a framework is needed that allows the selection and
   flexible combination of access and core network paths for uplink and
   downlink data delivery.

   For example, in uncongested scenarios, it would be beneficial to use
   WiFi access in both uplink and downlink for connecting to enterprise
   applications.  Whereas in congested scenarios, where use of WiFi in
   uplink by multiple users can lead to degraded capacity and increased
   delays due to contention, it would be beneficial to use scheduled LTE
   as uplink combined with WiFi as downlink.








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6.  Solution Principles

   This document proposes a Multiple Access Management Services(MAMS)
   framework for dynamic selection and flexible combination of access
   and core network paths as uplink and downlink for a device connected
   to multiple communication networks.  The multiple communication
   networks interwork at the user plane.  The selection of paths is
   based on negotiation of capabilities (of device and network) and
   network link quality between the user plane functional elements at
   the end-user device/client (C-MADP) and the network (N-MADP).NCM has
   the intelligence to setup and offer the best network path based on
   device and network capabilities, application needs and knowledge of
   the network state.

   The NCM communicates with the Client Connection Manager (CCM), a
   functional element in the device, for negotiation, sharing
   information on the network path conditions, and configuring usage of
   the network paths.  The messages between the NCM and CCM are carried
   as user plane data over any of the available network paths between
   the NCM and CCM.

7.  Requirements

   The requirements set out in this section are for the definition of
   behavior of the MAMS mechanism and the related functional elements.

7.1.  Access technology agnostic interworking

   The access nodes can be of different technology types like LTE, WiFi
   etc.  Since MAMS routes user plane data packets at the IP layer,
   which makes it agnostic to the type of underlying technology used at
   the access nodes.

7.2.  Support common transport deployments

   The network path selection and user data distribution should work
   transparently across transport deployments that include e2e IPsec,
   VPNs, and middleboxes like NATs and proxies.

7.3.  Independent Access path selection for Uplink and Downlink

   IP layer routing enables the client to transmit on uplink using one
   access and receive data on downlink using another access, allowing
   client and network connection manager to select the access paths for
   uplink and downlink independent of each other.






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7.4.  Core selection independent of uplink and downlink access

   A client is able to flexibly select the Core, independent of the
   access paths used to reach the Core, depending on the application
   needs.

7.5.  Adaptive network path selection

   The MAMS functional elements have the ability to determine the
   quality of each of the network paths, e.g. access link delay and
   capacity.  The network path quality information is fed into the logic
   for selection of combination of network paths to be used for
   transporting user data.  The path selection algorithm can use network
   path quality information, in addition to other considerations like
   network policies, for optimizing network usage and enhancing QoE
   delivered to the user.

7.6.  Multipath support and Aggregation of access link capacities

   MAMS supports distribution and aggregation of user data across
   multiple network paths at the IP layer.  MAMS allows the client to
   leverage the combined capacity of the multiple network connections by
   enabling simultaneous transport of user data over multiple network
   paths.  If required, packet re-ordering is done at the receiver,
   client(C-MADP) and/or the network (N-MADP), when user data packets
   are received out of order.  MAMS allows flexibility to choose the
   flow steering and aggregation protocol based on capabilities
   supported by the client and the network data plane entities, C-MADP
   and N-MADP respectively.  A MAMS multi-connection aggregation
   solution should support existing transport and network layer
   protocols like TCP, UDP, GRE.  If flow aggregation functions are
   realized using existing protocols such as Multi-Path TCP(MPTCP) and
   SCTP, MAMS framework should allow use and configuration of these
   aggregation protocols.

7.7.  Scalable mechanism based on user plane interworking

   The mechanism is based on user plane interworking, requiring only
   that the MAMS functional elements (NCM and N-MADP) should be added in
   the user plane path between the client and the network.  The
   interworking functionality is based on generically available routing
   and tunneling capabilities.  This makes solution easy to deploy and
   scale when different networks are added and removed.








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7.8.  Separate Control and Data plane functions

   The client negotiates with a network connection manager on the choice
   of access for both uplink and downlink, as well as the Core.  The
   network connection manager configures the actual user plane data
   distribution function.  This allows common control protocol to be
   used with multiple and potentially different user plane (e.g.
   tunneling) protocols, thus maintaining a clear separation between the
   control and data plane functions.  This makes the MAMS framework
   scalable and extensible, e.g. by being amenable to SDN based
   architecture and implementations.

7.9.  Lossless Path (Connection) Switching

   When switching data traffic from one path (connection) to another,
   packets may be lost or delivered out-of-order, which will have
   negative impacts on the performance of higher layer protocols, e.g.
   TCP.  MAMS should provide necessary mechanisms to ensure in-order
   delivery at the receiver, as well as support retransmissions at the
   transmitter during path switching.

7.10.  Concatenation and Fragmentation to adapt to MTU differences

   MAMS should support heterogeneous access networks, which may have
   different MTU sizes.  Moreover, tunneling protocols also have a big
   impact on the MTU size.  Hence, MAMS should support concatenation
   such that multiple IP packets may be encapsulated into a single
   packet to improve efficiency.  MAMS should also support fragmentation
   such that a single IP packet may be fragmented and encapsulated into
   multiple ones to avoid IP fragmentation.

7.11.  Configuring network middleboxes based on negotiated protocols

   MAMS enables identification of the optimal parameters that may be
   used for configuring the middle-boxes, like binding expiry times and
   supported MTUs, for efficient operation of the user plane protocols,
   depending on the data plane related parameters negotiated between the
   client and the network, e.g.  Configuring longer binding expiry time
   in NATs when UDP transport is used in contrast to the scenario where
   TCP is configured at the transport layer.

7.12.  Policy based Optimal path selection

   MAMS framework should support consideration of policies at the
   client, in addition to guidance from the network in determination of
   network paths selected for different application services.





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7.13.  MAMS Control signaling

   MAMS control signaling is carried over the user plane and is
   transparent to the transport protocols.  MAMS should support delivery
   of control signaling over the existing Internet protocols, e.g.  TCP
   or UDP.

7.14.  Service discovery and reachability

   MAMS offers the flexibility for the functional entity NCM to be
   collocated with any of the network elements and reachable via any of
   the available user plane paths.  MAMS framework allows the
   flexibility for the CCM to choose one of the available NCMs and
   exchange control plane signaling over any of the available user plane
   paths.  The choice of NCM can be based on considerations like, but
   not limited to, quality of link through which the NCM is reachable,
   Client preference, or pre-configuration etc.

8.  MAMS Reference Architecture
































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           +---------------------------------------------------+
           !     +---------------+       +---------------+     !
           !     !               !       !               !     !
           !     !Core(IP anchor)!       !Core(IP anchor)!     !
           !     !(network n)    !       !(network 1)    !     !
           !     !               !       !               !     !
           !     +---------------+       +---------------+     !
           !          +-----------------------+                !
           !          ! +-----+  +------+     !                !
           !          ! ! NCM !  !N-MADP|     !                !
           !          ! +-----+  +------+     !                !
           !          +-----------------------+                !
           !                                                   !
           !     +-----------+            +---------------+    !
           !     !           !            !               !    !
           !     !           !            !               !    !
           !     !access     !            !access         !    !
           !     !(network n)!            !(network 1)    !    !
           !     !           !            !               !    !
           !     +-----------+            +---------------+    !
           +---------------------------------------------------+


                           +-----------------+
                           ! +------+ +-----+!
                           ! |C-MADP| ! CCM !!
                           ! +------+ +-----+!
                           !        Client   !
                           +-----------------+

                   Figure 1: MAMS Reference Architecture

   Figure 1 illustrates MAMS architecture for the scenario of a client
   served by multiple (n) networks.  The NCM and N-MADP, functional
   elements, are introduced for supporting MAMS mechanisms.  The
   architecture is extendable to combine any number of networks, as well
   as any choice of participating network types (e.g.  LTE, WLAN,
   MuLTEfire, DSL) and deployment architectures (e.g. with user plane
   gateway function at the access edge).

   The N-MADP entity, at the network, handles the user data traffic
   forwarding across multiple network paths, as well as other user-plane
   functionalities, e.g. encapsulation, fragmentation, concatenation,
   reordering, retransmission, etc.  N-MADP is the distribution node for
   uplink and downlink data delivery with visibility of packets at the
   IP layer.  There can be multiple N-MADP entities in the network, e.g.
   to load balance across clients.  A single client can also be served
   by multiple N-MADP instances, e.g to address different user plane



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   requirements of multiple applications running on the client.
   Identification and distribution rules for different user data traffic
   types at the N-MADP are configured by the NCM.  The NCM configures
   the data delivery paths, access links, and user plane protocols to be
   used by N-MADP for downlink user data traffic.  The CCM configures
   the data delivery paths, access links, and user plane protocols to be
   used by C-MADP for uplink user data traffic based on the signaling
   exchanged with NCM.  In the UL, NCM allows selection of the core
   network path to be used by N-MADP to route uplink user data.

   The scheduling and load balancing algorithm at the N-MADP is
   configured by the NCM, based on static and/or dynamic network
   policies like assigning access and core paths for specific user data
   traffic type, data volume based percentage distribution, and link
   availability and feedback information from exchange of MAMS signaling
   with the CCM at the Client.

   At the client, the Client Connection Manager (CCM) manages the
   multiple network connections.  CCM is responsible for exchange of
   MAMS signaling messages with the NCM for supporting functions like UL
   and DL user network path configuration for transporting user data
   packets, link probing and reporting to support adaptive network path
   selection by NCM.  In the downlink, for the user data received by the
   client, it configures C-MADP such that application data packet
   received over any of the accesses to reach the appropriate
   application on the client.  In the uplink, for the data transmitted
   by the client, it configures the C-MADP to determine the best access
   links to be used for uplink data based on a combination of local
   policy and network policy delivered by the NCM.  The C-MADP entity
   handles all MAMS-specific user-plane functionalities at the client,
   e.g. encapsulation, fragmentation, concatenation, reordering,
   retransmissions, etc.  C-MADP is configured by CCM based on signaling
   exchange with NCM and local policies at the client.

   A user plane tunnel, e.g.  IPsec, may be needed for transporting user
   data packets between the N-MADP at the network and the C-MADP at the
   client.  The user plane tunnel is needed to ensure security and
   routability of the user plane packets between the N-MADP and the
   C-MADP.  The most common implementation of the user plane tunnel is
   the IPsec.  C-MADP receives the configuration from CCM indicates, to
   C-MADP, the access network interfaces over which the IPsec tunnel
   needs to be established, and for each of the indicated interfaces,
   the parameters (e.g.  N-MADP IPsec endpoint IP address reachable via
   the indicated access network interface) for setting up the IPsec
   tunnel.  C-MADP sets up the IPsec tunnel with the N-MADP via each of
   the indicated access network interfaces, using appropriate signaling,
   say IKEv2 and parameters provided by the CCM.  In deployments where
   N-MADP and the client are connected via a secure and direct IP path,



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   user plane tunnel may not be needed.  Note that the method for
   transporting user data packets between the N-MADP and the C-MADP
   should be general, based on the existing protocols, and consider
   minimizing overhead.

9.  Solution Principles



                            +----------------------------------------+
                            |   MAMS enabled Network of Networks     |
                            | +-----+    +-----+   +-----+    +------+
     +-----------------+    | |     |    |     |   |     |    |     ||
     |     Client      |    | |Netwo|    |Netwo|   |     |    |     ||
     | +-----+ +-----+ |    | |rk 1 |    |rk 2 +   |NCM  |    N-MADP||
     | C-MADP  |CCM  | |    | |(LTE)|    |(WiFi)   |     |    |     ||
     | +-----+ +-----+ |    | +-----+    +-----+   +-----+    +------|
     -+----------------+    +----------------------------------------+
      |   |       |              |          |         |          |
      |   |       |              |          |         |          |
      |   |    1.SETUP CONNECTION|          |         |          |
      |<-----------+------------>|          |         |          |
      |   |       |              +          +         |          |
      |   |       |  2. MAMS Capabilities Exchange    |          |
      |   |       |<-------------+----------+-------->|          |
      |   |       |              |          |         |          |
      |   |       +              |          |         |          |
      |   |    3. SETUP CONNECTION          |         |          |
      |<--+-------------------------------->|         |          |
      | 4c. Config| 4a. NEGOTIATE NETWORK PATHS, FLOW |4b. Config|
      | C-MADP    | PROTOCOL AND PARAMETERS |         |N-MADP    |
      |   |<----->|<-------------+----------+-------->|<-------->|
      |   |       |              +          +         |          |
      |   |       |5. ESTABLISH USER PLANE PATH ACCORDING TO     |
      |   |       | SELECTED FLOW PROTOCOL  |         |          |
      |   |<---------------------+----------+------------------->|
      |   |       |              |          |         |          |
      +   +       +              +          +         +          +


                         Figure 2: MAMS call flow

   Figure 2 illustrates the MAMS signaling mechanism for negotiation of
   network paths and flow protocols between the client and the network.
   In this example scenario, the client is connected to two networks
   (say LTE and WiFi).





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   1.  UE connects to network 1 and gets an IP address assigned by
       network 1.
   2.  CCM communicates with NCM functional element via the network 1
       connection and exchanges capabilities and parameters for MAMS
       operation.  Note: The NCM credentials (e.g.  NCM IP Address) can
       be made known to the UE by pre-provisioning.
   3.  Client sets up connection with network 2 and gets an IP address
       assigned by network 2.
   4.  CCM and NCM negotiate capabilities and parameters for
       establishment of network paths, which are then used to configure
       user plane functions N-MADP at the network and C-MADP at the
       client.

       4a.  CCM and NCM negotiate network paths, flow routing and
       aggregation protocols, and related parameters.

       4b.  NCM communicates with the N-MADP to exchange and configure
       flow aggregation protocols, policies and parameters in alignment
       with those negotiated with the CCM.

       4c.  CCM communicates with the C-MADP to exchange and configure
       flow aggregation protocols, policies and parameters in alignment
       with those negotiated with the NCM.


   5.  C-MADP and N-MADP establish the user plane paths, e.g. using IKE
       [RFC7296] signaling, based on the negotiated flow aggregation
       protocols and parameters specified by NCM.

   CCM and NCM can further exchange messages containing access link
   measurements for link maintenance by the NCM.  NCM evaluates the link
   conditions in the UL and DL across LTE and WiFi, based on link
   measurements reported by CCM and/or link probing techniques and
   determines the UL and DL user data distribution policy.  NCM and CCM
   also negotiate application level policies for categorizing
   applications, e.g.  based on DSCP, Destination IP address, and
   determining which of the available network paths, needs to be used
   for transporting data of that category of applications.  NCM
   configures N-MADP and CCM configures C-MADP based on the negotiated
   application policies.  CCM may apply local application policies, in
   addition to the application policy conveyed by the NCM.

10.  Implementation considerations

   MAMS builds on commonly available functions available on terminal
   devices that can be delivered as a software update over the popular
   end-user device operating systems, enabling rapid deployment and
   addressing the large deployed device base.



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11.  Applicability to Multi Access Edge Computing

   Multi Access Edge Computing, earlier known as Mobile edge computing
   (MEC), is an access-edge cloud platform being standardized at ETSI,
   whose initial focus was to improve quality of experience by
   leveraging intelligence at cellular (e.g. 3GPP technologies like LTE)
   access edge, and the scope is now being extended to support access
   technologies beyond 3GPP.  This applicability of the framework
   described in this document to the MEC platform has been evaluated and
   tested in different network configurations.

   The NCM is hosted on the MEC cloud server that is located in the user
   plane path at the edge of multi-technology access networks, and in a
   particular large venue use case at the edge of LTE and Wi-Fi access
   networks.  The NCM and CCM negotiate the network path combinations
   based on application needs and the necessary user plane protocols to
   manage the multiple paths.  The network conditions reported by the
   CCM to the NCM is used in addition to Radio Analytics application
   residing at the MEC to configure the uplink and downlink access paths
   according to changing radio and congestion conditions.

   The user plane functional element, N-MADP, can either be collocated
   with the NCM at the MEC cloud server (e.g.  MEC hosted applications),
   or placed at a separate network element like a common user plane
   gateway across the multiple networks.

   Also, even in scenarios where N-MADP is not deployed, NCM is
   leveraged to augment the traffic steering decisions at the device.

   The aim of these enhancements is to improve the end-user's quality of
   experience by leveraging the best network path based on application
   needs and network conditions, and building on the advantages of
   significantly reduced latency and the dynamic and real-time exposure
   of radio network information available at the MEC.

12.  Security Considerations

   This section details the security considerations for the MAMS
   framework.

12.1.  Data and Control plane security

   Signaling messages and the user data in MAMS framework rely on the
   security of the underlying network transport paths.  When this cannot
   be assumed, network connection manager configures use of protocols,
   like IPsec [RFC4301] [RFC3948], for securing user data and MAMS
   signaling messages.




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13.  Contributors

   This protocol is the outcome of work by many engineers, not just the
   authors of this document.  In alphabetical order, the contributors to
   the project are: Barbara Orlandi, Bongho Kim,David Lopez-Perez, Doru
   Calin, Jonathan Ling, Krishna Pramod A., Lohith Nayak, Michael
   Scharf.

14.  References

14.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC4301]  Kent, S. and K. Seo, "Security Architecture for the
              Internet Protocol", RFC 4301, DOI 10.17487/RFC4301,
              December 2005, <https://www.rfc-editor.org/info/rfc4301>.

14.2.  Informative References

   [RFC3948]  Huttunen, A., Swander, B., Volpe, V., DiBurro, L., and M.
              Stenberg, "UDP Encapsulation of IPsec ESP Packets",
              RFC 3948, DOI 10.17487/RFC3948, January 2005,
              <https://www.rfc-editor.org/info/rfc3948>.

   [RFC7296]  Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T.
              Kivinen, "Internet Key Exchange Protocol Version 2
              (IKEv2)", STD 79, RFC 7296, DOI 10.17487/RFC7296, October
              2014, <https://www.rfc-editor.org/info/rfc7296>.

Authors' Addresses

   Satish Kanugovi
   Nokia

   Email: satish.k@nokia.com


   Subramanian Vasudevan
   Nokia

   Email: vasu.vasudevan@nokia.com






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   Florin Baboescu
   Broadcom

   Email: florin.baboescu@broadcom.com


   Jing Zhu
   Intel

   Email: jing.z.zhu@intel.com


   Shuping Peng
   Huawei

   Email: pengshuping@huawei.com


   Julius Mueller
   AT&T

   Email: jm169k@att.com


   SungHoon Seo
   Korea Telecom

   Email: sh.seo@kt.com























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