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INTAREA                                                          J. Zhu
Internet Draft                                                    Intel
Intended status: Standards Track                                 S. Seo
Expires: December 16, 2017                                Korea Telecom
                                                             S. Kanugovi
                                                                   Nokia
                                                                 S. Peng
                                                                  Huawei
                                                           June 16, 2017

        User-Plane Protocols for Multiple Access Management Service
                  draft-zhu-intarea-mams-user-protocol-02


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
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   This Internet-Draft will expire on December 16, 2017.

Copyright Notice

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

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   publication of this document. Please review these documents
   carefully, as they describe your rights and restrictions with
   respect to this document. Code Components extracted from this



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   document must 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.

Abstract

   Today, a device can be simultaneously connected to multiple
   communication networks based on different technology implementations
   and network architectures like WiFi, LTE, DSL. In such multi-
   connectivity scenario, it is desirable to combine multiple access
   networks or select the best one to improve quality of experience for
   a user and improve overall network utilization and efficiency. This
   document presents the u-plane protocols for a multi access
   management services (MAMS) framework that can be used to flexibly
   select the combination of uplink and downlink access and core
   network paths having the optimal performance, and user plane
   treatment for improving network utilization and efficiency and
   enhanced quality of experience for user applications.

Table of Contents

   1. Introduction...................................................3
   2. Terminologies..................................................3
   3. Conventions used in this document..............................3
   4  MAMS User-Plane Protocols......................................4
      4.1   MX Adaptation Layer......................................4
      4.2   Trailer-based MX Convergence Layer.......................5
         4.2.1    Trailer-based MX PDU Format........................5
         4.2.2    MX Fragmentation...................................7
         4.2.3    MX Concatenation...................................8
      4.3   MPTCP-based MX Convergence Layer.........................9
      4.4   GRE as MX Convergence Layer.............................10
         5.4.1    Transmitter Procedures............................11
         5.4.2    Receiver Procedures...............................11
      5.5   Co-existence of MX Adaptation and MX Convergence Sublayers
            11
   6  MX Convergence Control........................................12
      6.1   Keep-Alive Message......................................13
      6.2   Probe REQ/ACK Message...................................13
   7  Security Considerations.......................................14
   8  IANA Considerations...........................................14
   9  Contributing Authors..........................................14
   10 References....................................................14
      10.1  Normative References....................................14
      10.2  Informative References..................................14




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1. Introduction

   Multi Access Management Service (MAMS) [MAMS] is a programmable
   framework to select and configure network paths, as well as adapt to
   dynamic network conditions, when multiple network connections can
   serve a client device. It is based on principles of user plane
   interworking that enables the solution to be deployed as an overlay
   without impacting the underlying networks.

   This document presents the u-plane protocols for enabling the MAMS
   framework. 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 exchange 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 technology of the participating links. This allows the
   scheme to be scalable for addition of newer accesses and for
   independent evolution of the existing access technologies.

2. Terminologies

   Anchor Connection: refers to the network path from the N-MADP to the
   Application Server that corresponds to a specific IP anchor that has
   assigned an IP address to the client

   Delivery Connection: refers to the network path from the N-MADP to
   the C-MADP.

   "Network Connection Manager" (NCM), "Client Connection Manager"
   (CCM), "Network Multi Access Data Proxy" (N-MADP), and "Client Multi
   Access Data Proxy" (C-MADP) in this document are to be interpreted
   as described in [MAMS].

3. 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].

   The terminologies "Network Connection Manager" (NCM), "Client
   Connection Manager" (CCM), "Network Multi Access Data Proxy" (N-
   MADP), and "Client Multi Access Data Proxy" (C-MADP) in this
   document are to be interpreted as described in [MAMS].





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4  MAMS User-Plane Protocols

Figure 1 shows the MAMS u-plane protocol stack as specified in
[MAMS_CP].
             +-----------------------------------------------------+
             |      User Payload (e.g. IP PDU)                     |
             |-----------------------------------------------------|
          +--|-----------------------------------------------------|--+
          |  |-----------------------------------------------------|  |
          |  | Multi-Access (MX) Convergence Sublayer              |  |
          |  |-----------------------------------------------------|  |
          |  |-----------------------------------------------------|  |
          |  | MX Adaptation  | MX Adaptation | MX Adaptation      |  |
          |  | Sublayer       | Sublayer      | Sublayer           |  |
          |  | (optional)     | (optional)    | (optional)         |  |
          |  |-----------------------------------------------------|  |
          |  | Access #1 IP   | Access #2 IP  | Access #3 IP       |  |
          |  +-----------------------------------------------------+  |
          +-----------------------------------------------------------+
                 Figure 1: MAMS U-plane Protocol Stack


It consists of the following two Sublayers:

o Multi-Access (MX) Convergence Sublayer: This layer performs multi-
  access specific tasks, e.g., access (path) selection, multi-link
  (path) aggregation, splitting/reordering, lossless switching,
  fragmentation, concatenation, keep-alive, probing etc.
o Multi-Access (MX) Adaptation Sublayer: This layer performs functions
  to handle tunneling, network layer security, and NAT.

The MX convergence sublayer operates on top of the MX adaptation
sublayer in the protocol stack. From the Transmitter perspective, a
User Payload (e.g. IP PDU) is processed by the convergence sublayer
first, and then by the adaptation sublayer before being transported
over a delivery access connection; From the Receiver perspective, an IP
packet received over a delivery connection is processed by the MX
adaptation sublayer first, and then by the MX convergence sublayer.

4.1  MX Adaptation Layer

The MX adaptation layer supports the following mechanisms and protocols
while transmitting user plane packets on the network path:



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o UDP Tunneling: The user plane packets of the anchor connection can be
  encapsulated in a UDP tunnel of a delivery connection between the N-
  MADP and C-MADP.
o IPsec Tunneling: The user plane packets of the anchor connection are
  sent through an IPSec tunnel of a delivery connection.
o Client Net Address Translation (NAT): change the Client IP address of
  user plane packet of the anchor connection, and send it over a
  delivery connection.
o Pass Through: The user plane packets are passing through without any
  change over the anchor connection.

The MX adaptation layer also supports the following mechanisms and
protocols to ensure security of user plane packets over the network
path.

o IPSec Tunneling: An IPsec [RFC7296] tunnel is established between the
  N-MADP and C-MADP on the network path that is considered untrusted.
o DTLS: If UDP tunneling is used on the network path that is considered
  "untrusted", DTLS (Datagram Transport Layer Security) [RFC6347] can
  be used.

The Client NAT method is the most efficient due to no tunneling
overhead. It SHOULD be used if a delivery connection is "trusted" and
without NAT function on the path.

The UDP or IPSec Tunnelling method SHOULD be used if a delivery
connection has a NAT function placed on the path.

4.2  Trailer-based MX Convergence Layer

4.2.1 Trailer-based MX PDU Format

Trailer-based MX convergence integrates multiple connections into a
single e2e IP connection. It operates between Layer 2 (L2) and Layer 3
(network/IP).

                   <-- MX Data PDU Payload ------->
          +------------------------------------------------------+
          | IP hdr |        IP payload             | MX Trailer  |
          +------------------------------------------------------+
         Figure 2: Trailer-based Multi-Access (MX) Data PDU Format

Figure 2 shows the trailer-based Multi-Access (MX) PDU (Protocol Data
Unit) format. A MX PDU MAY carry multiple IP PDUs in the payload if
concatenation is supported, and MAY carry a fragment of the IP PDU if
fragmentation is supported.


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The MX trailer may consist of the following fields:

o MX flags (e.g. 1 byte): Bit 0 is the most significant bit, bit 7 is
  the least significant bit. Bit 6 and 7 are reserved for future.
     + Next Header Present (bit 0): If the Next Header Present bit is
       set to 1, then the Next Header field is present and contains
       valid information.
     + Connection ID Present (bit 1): If the Connection ID Present bit
       is set to 1, then the Connection ID field is present and
       contains valid information.
     + Traffic Class Present (bit 2): If the Traffic Class Present bit
       is set to 1, then the Traffic Class field is present and
       contains valid information.
     + Sequence Number Present (bit 3): If the Sequence Number Present
       bit is set to 1, then the Sequence Number field is present and
       contains valid information.
     + Packet Length Present (bit 4): If the Packet Length Present bit
       is set to 1, then the First SDU Length field is present and
       contains valid information.
     + Fragmentation Control Present (bit 5): If the Fragmentation
       Control Present bit is set to 1, then the Fragmentation Control
       field is present and contains valid information.
     + Bit 6~7: reserved
o Next Header (e.g. 1 byte): the IP protocol type of the (first) IP
  packet in a MX PDU
o Connection ID (e.g.1 byte): an unsigned integer to identify the
  anchor connection of the IP packets in a MX PDU
o Traffic Class (TC) ID (e.g. 1 byte): an unsigned integer to identify
  the traffic class of the IP packets in a MX PDU, for example Data
  Radio Bearer (DRB) ID [LWIPEP] for a cellular (e.g. LTE) connection
o Sequence Number (e.g. 2 bytes): an auto-incremented integer to
  indicate order of transmission of the IP packet, needed for lossless
  switching or multi-link (path) aggregation or fragmentation.
o First SDU Length (e.g. 2 bytes): the length of the first IP packet,
  only included if a MX PDU contains multiple IP packets, i.e.
  concatenation.
o Fragmentation Control (FC) (e.g. 1 Byte): to provide necessary
  information for re-assembly, only needed if a MX PDU carries
  fragments, i.e. fragmentation.

Figure 3 shows the MX trailer format with all the fields present. The
MX flags are always encoded in the last octet of the MX Trailer at the
end of a MX PDU. Hence, the Receiver SHOULD first decode the MX flags
field to determine the length of the MX trailer, and then decode each
MX field accordingly.

      0                   1                   2                   3


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      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     | Next Header   | Connection ID |   TC ID       |   Sequence

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

       Number        |      First SDU Length         |      FC       |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |  MX Flags     |

     +-+-+-+-+-+-+-+-+

                        Figure 3: MX Trailer Format

Moreover, the following fields of the IP header of the MX PDU are
changed as follows:

o  Protocol Type: "114" to indicate that the presence of MX trailer
(i.e. the trailer based MAMS u-plane protocol is a "0-hop" protocol,
not subject to IP routing)
o  IP length: add the length of "MX Trailer" to the length of the
original IP packet
o  IP checksum: recalculate after changing "Protocol Type" and "IP
Length"

The MX u-plane protocol can support multiple Anchor connections
simultaneously, each of which is uniquely identified by Connection ID.
It can also support multiple traffic classes per connection, each of
which is identified by Traffic Class ID.

Moreover, the MX trailer format MAY be negotiated dynamically between
NCM and CCM. For example, NCM can send a control message to indicate
which of the above fields SHOULD be included for individual delivery
connection, on downlink and uplink, respectively.

4.2.2 MX Fragmentation

The Trailer-based MX Convergence Layer SHOULD support MX fragmentation
if a delivery connection has a smaller maximum transmission unit (MTU)
than the original IP packet (MX SDU), and IP fragmentation is not
supported or enabled on the connection.   The MX fragmentation
procedure is similar to IP fragmentation [RFC791] in principle, but
with the following two differences for less overhead:


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o The fragment offset unit is fragment not eight-bye blocks.
o The maximum number of fragments per MX SDU is 2^7 (=128)

The Fragmentation Control (FC) field in the MX Trailer contains the
following bits:

o Bit #7: a More Fragment (MF) flag to indicate if the fragment is the
  last one (0) or not (1)
o Bit #0~#6: Fragment Offset (in units of fragments) to specify the
  offset of a particular fragment relative to the beginning of the MX
  SDU

A MX PDU carries a whole MX SDU without fragmentation if the FC field
is set to all "0"s or the FC field is not present in the trailer.
Otherwise, the MX PDU contains a fragment of the MX SDU.

The Sequence Number field in the trailer is used to distinguish the
fragments of one MX SDU from those of another. The Fragment Offset (FO)
field tells the receiver the position of a fragment in the original MX
SDU. The More Fragment (MF) flag indicates the last fragment.

To fragment a long MX SDU, the MADP transmitter creates two MX PDUs and
copies the contents of the IP header fields from the long MX PDU into
the IP header of both MX PDUs. The length field in the IP header of MX
PDU SHOULD be changed to the length of the MX PDU, and the protocol
type SHOULD be changed to "114", indicating the presence of the MX
trailer.

The data of the long MX SDU is divided into two portions based on the
MTU size of the delivery connection. The first portion of the data is
placed in the first MX PDU.  The MF flag is set to 1, and the FO field
is set to 0. The second portion of the data is placed in the second MX
PDU. The MF flag is set to 0, and the FO field is set to 1. This
procedure can be generalized for an n-way split, rather than the two-
way split described.

To assemble the fragments of a MX SDU, the MADP receiver combines MX
PDUs that all have the same MX Sequence Number (in the trailer). The
combination is done by placing the data portion of each fragment in the
relative order indicated by the Fragment Offset in that fragment's MX
trailer. The first fragment will have the Fragment Offset zero, and the
last fragment will have the More-Fragments flag reset to zero.

4.2.3 MX Concatenation

The Trailer-based MX Convergence Layer MAY support MX concatenation if
a delivery connection has a larger maximum transmission unit (MTU) than
the original IP packet (MX SDU).

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The First SDU Length (FSL) field SHOULD be present in the MX Trailer if
a MX PDU contains multiple MX SDUs, i.e. concatenation, and it
indicates the length of the first MX SDU in the PDU.

Only the MX SDUs with the same client address, the same anchor
connection and the same Traffic Class MAY be concatenated.

To concatenate two or more MX SDUs, the MADP transmitter creates one MX
PDU and copies the contents of the IP header field from the first MX
SDU into the IP header of the MX PDU. The data of the first MX SDU is
placed in the first portion of the data of the MX PDU. The whole second
MX SDU is then placed in the second portion of the data of the MX PDU
(Figure 4). The procedure continues till the MX PDU size reaches the
MTU of the delivery connection.

To disaggregate a MX PDU, the MADP receiver first obtains the length of
the first MX SDU from the First SDU Length field in the trailer, and
decodes the first MX SDU. The MADP receiver then obtains the length of
the second MX SDU based on the length field in the second MX SDU IP
header, and decodes the second MX SDU. The procedure continues till no
byte is left in the MX PDU.

If a MX PDU contains multiple SDUs, the SN field in the MX trailer is
for the last MX SDU, and the SN of other SDU carried by the same PDU
can be obtained according to its order in the PDU. For example, if the
SN field is 6 and a MX PDU contains 3 SDUs (IP packets), then the SN is
4, 5, and 6 for the first, second, and the last IP packet in the PDU,
respectively.

              <---- MX Data PDU Payload ------------>
     +------------------------------------------------------------+
     | IP hdr | IP payload  | IP hdr |  IP payload  | MX Trailer  |
     +------------------------------------------------------------+
                Figure 4: MX PDU Format with Concatenation

4.3  MPTCP-based MX Convergence Layer

Figure 5 shows the MAMS u-plane protocol stack based on MPTCP. Here,
MPTCP is reused as the "MX Convergence sub-layer" protocol. Multiple
access networks are combined into a single MPTCP connection. Hence, no
new u-plane protocol or PDU format is needed in this case.

          |-----------------------------------------------------|
          |                       MPTCP                         |
          |-----------------------------------------------------|
          |  TCP           |   TCP         |      TCP           |
          |-----------------------------------------------------|

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          | MX Adaptation  | MX Adaptation | MX Adaptation      |
          | Sublayer       | Sublayer      | Sublayer           |
          | (optional)     | (optional)    | (optional)         |
          |-----------------------------------------------------|
          | Access #1 IP   | Access #2 IP  | Access #3 IP       |
          +-----------------------------------------------------+
    Figure 5: MAMS U-plane Protocol Stack with MPTCP as MX Convergence
                                   Layer


If NCM determines that N-MADP is to be instantiated with MPTCP as the
MX Convergence Protocol, it exchanges the support of MPTCP capability
in the discovery and capability exchange procedures [MAMS_CP]. MPTCP
proxy protocols [MPProxy] [MPPlain] SHOULD be used to manage traffic
steering and aggregation over multiple delivery connections.

4.4  GRE as MX Convergence Layer

Figure 6 shows the MAMS u-plane protocol stack based on GRE (Generic
Routing Encapsulation) [GRE2784]. Here, GRE is reused as the "MX
Convergence sub-layer" protocol. Multiple access networks are combined
into a single GRE connection. Hence, no new u-plane protocol or PDU
format is needed in this case.

          +-----------------------------------------------------+
          |      User Payload (e.g. IP PDU)                     |
          |-----------------------------------------------------|
          |              GRE as MX Convergence Layer            |
          |-----------------------------------------------------|
          |        GRE Delivery Protocol (e.g. IP)              |
          |-----------------------------------------------------|
          | MX Adaptation  | MX Adaptation | MX Adaptation      |
          | Sublayer       | Sublayer      | Sublayer           |
          | (optional)     | (optional)    | (optional)         |
          |-----------------------------------------------------|
          | Access #1 IP   | Access #2 IP  | Access #3 IP       |
          +-----------------------------------------------------+
     Figure 6: MAMS U-plane Protocol Stack with GRE as MX Convergence
                                   Layer


If NCM determines that N-MADP is to be instantiated with GRE as the MX
Convergence Protocol, it exchanges the support of GRE capability in the
discovery and capability exchange procedures [MAMS_CP].





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5.4.1 Transmitter Procedures

Transmitter is the N-MADP or C-MADP instance, instantiated with GRE as
the  convergence  protocol  that  transmits  the  GRE  packets.  The
Transmitter receives the User Payload (e.g. IP PDU), encapsulates it
with a GRE header and Delivery Protocol (e.g. IP) header to generate
the GRE Convergence PDU.

When IP is used as the GRE delivery protocol, the IP header information
(e.g. IP address) can be created using the IP header of the user
payload or a virtual IP address. The "Protocol Type" field of the
delivery header is set to 47 (or 0X2F)[IANA].

The GRE header fields are set as specified below

  - If the transmitter is a C-MADP instance, then set the LSB 16 bits
     to the value of Connection ID for the Anchor Connection associated
     with the user payload or set to 0xFFFF, if no Anchor Connection ID
     needs to be specified.
  - All other fields in the GRE header including the remaining bits in
     the key field are set per [GRE_2784][GRE_2890].

5.4.2 Receiver Procedures

Receiver is the N-MADP or C-MADP instance, instantiated with GRE as the
convergence protocol, that receives the GRE packets. The receiver
processes  the  received  packets  per  the  GRE  procedures  [GRE_2784,
GRE_2890] and retrieves the GRE header.

  - If the Receiver is an N-MADP instance,
       o Unless the LSB 16 Bits of the Key field are 0xFFFF, they are
          interpreted as the Connection ID of Anchor Connection for the
          user payload. This is used to identify the network path over
          which the User Payload (GRE Payload) is to be transmitted.
  - All other fields in the GRE header, including the remaining bits
     in the Key field, are processed per [GRE_2784][GRE_2890].

The GRE Convergence PDU is passed onto the MX Adaptation Layer (if
present) before delivery over one of the network paths.

5.5   Co-existence of MX Adaptation and MX Convergence Sublayers

MAMS u-plane protocols support multiple combinations and instances of
user plane protocols to be used in the MX Adaptation and the
Convergence sublayers.

For example, one instance of the MX Convergence Layer can be MPTCP
Proxy [MPProxy] [MPPlain] and another instance can be Trailer-based.

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The MX Adaptation for each can be either UDP tunnel or IPsec. IPSec may
be set up for network paths considered as untrusted by the operator, to
protect the TCP subflow between client and MPTCP proxy traversing that
network path.

Each of the instances of MAMS user plane, i.e. combination of MX
Convergence and MX Adaptation layer protocols, can coexist
simultaneously and independently handle different traffic types.

6  MX Convergence Control

A UDP connection may be configured between C-MADP and N-MADP to
exchange control messages for keep-alive or path quality estimation.
The N-MADP end-point IP address and UDP port number of the UDP
connection is used to identify MX control PDU. Figure 7 shows the MX
control PDU format with the following fields:

o Type (1 Byte): the type of the MX control message
     + 0: Keep-Alive
     + 1: Probe REQ/ACK
     + Others: reserved
o CID (1 Byte): the connection ID of the delivery connection for
  sending out the MX control message
o MX Control Message (variable): the payload of the MX control message

Figure 8 shows the MX convergence control protocol stack, and MX
control PDU goes through the MX adaptation sublayer the same way as MX
data PDU.

                        <----MX Control PDU Payload --------------->
+------------------------------------------------------------------+
| IP header | UDP Header| Type | CID |       MX Control Message    |
+------------------------------------------------------------------+
                      Figure 7: MX Control PDU Format

          |-----------------------------------------------------|
          |          MX Convergence Control Messages            |
          |-----------------------------------------------------|
          |                  UDP/IP                             |
          |-----------------------------------------------------|
          | MX Adaptation  | MX Adaptation | MX Adaptation      |
          | Sublayer       | Sublayer      | Sublayer           |
          | (optional)     | (optional)    | (optional)         |
          |-----------------------------------------------------|
          | Access #1 IP   | Access #2 IP  | Access #3 IP       |
          +-----------------------------------------------------+


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              Figure 8: MX Convergence Control Protocol Stack

6.1  Keep-Alive Message

The "Type" field is set to 0 for Keep-Alive messages. C-MADP may send
out Keep-Alive message periodically over one or multiple delivery
connections, especially if UDP tunneling is used as the adaptation
method for the delivery connection with a NAT function on the path.

A Keep-Alive message is 2 bytes long, and consists of the following
fields:

  o Keep-Alive Sequence Number (2 Bytes): the sequence number of the
     keep-alive message

6.2  Probe REQ/ACK Message

The "Type" field is set to 1 for Probe REQ/ACK messages.

N-MADP may send out the Probe REQ message for path quality estimation.
In response, C-MADP may send back the Probe ACK message.

A Probe REQ message consists of the following fields:

  o Probing Sequence Number (2 Bytes): the sequence number of the
     Probe REQ message
  o Probing Flag (1 Byte):
       + Bit #0: a Probe ACK flag to indicate if the Probe ACK message
          is expected (1) or not (0);
       + Bit #1: a Probe Type flag to indicate if the Probe REQ/ACK
          message is sent during the initialization phase (0) when the
          network path is not included for transmission of user data or
          the active phase (1) when the network path is included for
          transmission of user data;
       + Bit #2~7: reserved
  o Padding (variable)

The "Padding" field is used to control the length of Probe REQ message.

C-MADP SHOULD send out the Probe ACK message in response to a Probe REQ
message with the Probe ACK flag set to "1".

A Probe ACK message is 3 bytes long, and consists of the following
fields:

  o Probing Acknowledgement Number (2 Bytes): the sequence number of
     the corresponding Probe REQ message


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7  Security Considerations

User data in MAMS framework rely on the security of the underlying
network transport paths.  When this cannot be assumed, NCM configures
use of appropriate protocols for security, e.g. IPsec [RFC4301]
[RFC3948], DTLS [RFC6347].

8  IANA Considerations

TBD

9  Contributing Authors

The editors gratefully acknowledge the following additional
contributors in alphabetical order: Salil Agarwal/Nokia, Hema
Pentakota/Nokia.

10 References

10.1 Normative References

   [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
             Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC4301] Kent, S. and K. Seo, "Security Architecture for the
             Internet Protocol", RFC 4301, DOI10.17487/RFC4301,
             December 2005, <http://www.rfc-editor.org/info/rfc4301>.

10.2 Informative References

   [RFC6347] Rescorla, E. and N. Modadugu, "Datagram Transport Layer
             Security Version 1.2", RFC 6347, January
             2012,<http://www.rfc-editor.org/info/rfc6347>.

   [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, <http://www.rfc-editor.org/info/rfc7296>.

   [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,<http://www.rfc-
             editor.org/info/rfc3948>.

   [MPProxy] X. Wei, C. Xiong, and E. Lopez, "MPTCP proxy mechanisms",
             https://tools.ietf.org/html/draft-wei-mptcp-proxy-
             mechanism-02


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Internet-Draft          MAMS u-plane protocols                June 2017


   [MPPlain] M. Boucadair et al, "An MPTCP Option for Network-Assisted
             MPTCP", https://www.ietf.org/id/draft-boucadair-mptcp-
             plain-mode-09.txt

   [MAMS] S. Kanugovi, S. Vasudevan, F. Baboescu, and J. Zhu, "Multiple
             Access Management Protocol",
             https://tools.ietf.org/html/draft-kanugovi-intarea-mams-
             protocol-03

   [MAMS_CP] S. Kanugovi, et al., "Control Plane Protocols and
             Procedures for Multiple Access Management Services"

   [GRE2784] D. Farinacci, et al., "Generic Routing Encapsulation
             (GRE)", RFC 2784 March 2000, <http://www.rfc-
             editor.org/info/rfc2784>.

   [GRE2890] G. Dommety, "Key and Sequence Number Extensions to GRE",
             RFC 2890 September 2000, <http://www.rfc-
             editor.org/info/rfc2890>.

   [IANA]    https://www.iana.org/assignments/protocol-
             numbers/protocol-numbers.xhtml

   [LWIPEP] 3GPP TS 36.361, "Evolved Universal Terrestrial Radio Access
             (E-UTRA); LTE-WLAN Radio Level Integration Using Ipsec
             Tunnel (LWIP) encapsulation; Protocol specification"

   [RFC791] Internet Protocol, September 1981

Authors' Addresses

   Jing Zhu

   Intel

   Email: jing.z.zhu@intel.com

   SungHoon Seo

   Korea Telecom

   Email: sh.seo@kt.com

   Satish Kanugovi

   Nokia

   Email: satish.k@nokia.com

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   Shuping Peng

   Huawei

   Email: pengshuping@huawei.com












































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