[Docs] [txt|pdf] [Tracker] [Email] [Diff1] [Diff2] [Nits]

Versions: 00 01

NFVRG                                                              R. Gu
Internet-Draft                                                     S. Hu
Intended status: Informational                              China Mobile
Expires: January 3, 2018                                    July 2, 2017


         Control and User Plane Separation Architecture of BNG
                draft-gu-nfvrg-cloud-bng-architecture-01

Abstract

   This document defines the new architecture of BNG devices with
   control plane (CP) and user plane (UP) separation.  BNG-CP is a user
   control management component while BNG-UP takes responsibility as the
   network edge and user policy implementation componenet.  Both BNG-CP
   and BNG-UP are core components for fixed broadband services and
   deployed separately at different network layer in actual network.

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 http://datatracker.ietf.org/drafts/current/.

   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 January 3, 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
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   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 document must
   include Simplified BSD License text as described in Section 4.e of




Gu & Hu                  Expires January 3, 2018                [Page 1]


Internet-Draft       C/U Separated BNG Architecture            July 2017


   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   2
   3.  Definition of terms . . . . . . . . . . . . . . . . . . . . .   2
   4.  C/U separated BNG architecture  . . . . . . . . . . . . . . .   3
   5.  C/U separated BNG use case  . . . . . . . . . . . . . . . . .   4
   6.  Advantages of C/U seperated BNG . . . . . . . . . . . . . . .   8
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .   8
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   8
   9.  Normative References  . . . . . . . . . . . . . . . . . . . .   8
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   9

1.  Introduction

   BNG device is defined as an Ethernet-centric IP edge router, and the
   aggregation point for the user traffic.  It performs Ethernet
   aggregation and packets forwarding via IP/MPLS, and supports user
   management, access protocols termination, QoS and policy management,
   etc.

   The basic idea of control plane and user plane separation is to
   extract and centralize the user management function of multiple BNG
   devices forming a separate and concentrated CP, while UP takes
   function as traditional router's control plane and BNG forwarding
   plane.  Thus a BNG is constructed of CP and UP which is benefit in
   cloud-based BNG with the advantages of resource utilization
   improvement, resource control centralization, new service rapid
   provision and so on.

2.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119].

3.  Definition of terms

   AAA:Authentication Authorization Accounting

   BNG:Broadband Network Gateway

   CP:Control Plane

   DHCP:Dynamic Host Configuration Protocol



Gu & Hu                  Expires January 3, 2018                [Page 2]


Internet-Draft       C/U Separated BNG Architecture            July 2017


   MANO:Management and Orchestration

   NFV:Network Function Virtualization

   PPPoE:Point to Point Protocol over Ethernet

   UP: User Plane

4.  C/U separated BNG architecture

   There are two parts of functions in traditional BNG: one is user
   access management function, the other is router function.  While in
   cloud-based BNG, we find out that tearing these two functions apart
   can make a difference.  Actually the user management function can be
   centralized deployed as a concentrated module or device which can be
   called BNG-CP (Control Plane).  The reserved functions such as router
   function and forwarding engine can be deployed in the form of BNG
   User Plane.  Thus the Cloud-based BNG architecture is made up of
   control plane and user plane.

    +--------------------------------------------------------------+
    |+----------+ +---+ +----------+ +------++------++-----------+ |
    || Address  | |AAA| |Subscriber| |Radius||PPPoE/||    UP     | |
    ||management| |   | |management| |      ||IPoE  ||management | |
    |+----------+ +---+ +----------+ +------++------++-----------+ |
    |                              CP                              |
    +-----------+++---------------------------------+++------------+
                |||                                 |||
                |||                                 |||
                |||                                 |||
    +-----------+++-------------+      +------------+++-----------+
    |  +------------------+     |      |  +------------------+    |
    |  | Routing control  |     |      |  | Routing control  |    |
    |  +------------------+     | ...  |  +------------------+    |
    |  +------------------+     |      |  +------------------+    |
    |  |Forwarding engine |     |      |  |Forwarding engine |    |
    |  +------------------+  UP |      |  +------------------+  UP|
    +---------------------------+      +--------------------------+


               Figure 1: Architecture of C/U Seperation BNG

   The CP is a user control management component that supports

   (1)Address management:unified address pool management

   (2)AAA and RADIUS:cooperation with the RADIUS server and others to
   implement AAA for access users



Gu & Hu                  Expires January 3, 2018                [Page 3]


Internet-Draft       C/U Separated BNG Architecture            July 2017


   (3)Subscriber management:user entry management and forwarding policy
   management

   (4)PPPoE/IPoE:process user dialup packets of PPPoE/IPoE

   (5)UP management:management of UP interface status, and the setup,
   deletion, maintenance of channels between CP and UP

   The UP is a network edge and user policy implementation component,
   including

   (1)Control plane functions including routing, multicast and MPLS

   (2)Forwarding plane functions including traffic forwarding, QoS and
   traffic statistics collection

5.  C/U separated BNG use case


































Gu & Hu                  Expires January 3, 2018                [Page 4]


Internet-Draft       C/U Separated BNG Architecture            July 2017


+------------------------------------------------------------------+
|        Neighboring policy and resource management systems        |
|                                                                  |
|   +-------------+   +-----------+   +---------+   +----------+   |
|   |Radius Server|   |DHCP Server|   |   EMS   |   |   MANO   |   |
|   +-------------+   +-----------+   +---------+   +----------+   |
+--------------------------------+---------------------------------+
                                 |
                                 |
                                 |
               +-----------------+-----------------+
               |                                   |
               |              BNG-CP               |
               |                                   |
               +---------------+------------+------+
        Service|      Control|  Management|      |||
    Interface|    Interface|    Interface|          |||
(VXLAN-GPE)|    (OF,etc.)|    (Netconf)|               |||
        |              |            |                     |||
      +--------------+------------+         +---------------------------+
      |                           |         |                           |
      |           BNG-UP          |         |           BNG-UP          |
      |                           |         |                           |
      +-------------+-------------+         +--------------+------------+
                    |                                      |
                    |                                      |
      +-------------+-------------+         +--------------+------------+
      |                           |         |                           |
      |        Access Network     |         |        Access Network     |
      |                           |         |                           |
      +-+-----------+-----------+-+         +-+--------+-----------+----+
        |           |           |             |        |           |
        |           |           |             |        |           |
        |           |           |             |        |           |
  +-----++     +----+-+     +---+--+     +----+-+   +----+-+      +--+---+
  |User11|     |User12| ... |User1N|     |User21|   |User22|  ... |User2N|
  +------+     +------+     +------+     +------+   +------+      +------+


                       Figure 2: Cloud BNG use case

   In the actual deployment, a C/U separated BNG device is composed of
   CP and UPs.  CP is centralized deployed which takes responsiblity of
   a user control management component managing UP's resources such as
   the user entry and forwarding policy.  And UP is distributed in the
   bottom acting as a network edge and user policy implementation
   component.




Gu & Hu                  Expires January 3, 2018                [Page 5]


Internet-Draft       C/U Separated BNG Architecture            July 2017


   In order to fulfill a service, Neighboring policy and resource
   management systems is deployed outside.  In the neighboring system,
   different service systems such as RADIUS server,DHCP server and EMS
   are included.  Besides if BNG-CP is virtualized as a NFV.  The NFV
   infrastructure management system MANO is also included here.  BNG-CP
   has connections with the outside neighboring systems to transmit
   management traffic.

   There are three kinds of interfaces between BNG-CP and BNG-UP
   according to its traffic catergories: Service Interface, Control
   Interface, and Management Interface.  Service Interface is used to
   transmit PPPoE/IPoE packets for the authentication.  Control
   Interface is used for setting forwarding entries on UP.  Some choose
   OpenFlow as the protocol.  Management Interface is used to carry out
   basic configurations through NETCONF.

   Besides, now we have three related drafts which describes these
   interfaces in detail.  One is VXLAN-GPE extention draft for C/U
   separated BNG related with Servie Interface in [draft-huang-nov3-
   vxlan-gpe-extension-for-vbng-00].  One is YANG data model for
   Management Interface in [draft-hu-opsawg-cu-separation-yang-model-
   00].  The other is the information model covering Control Interface
   and Management Interface which makes the abstraction of information
   in modeling in [draft-wcg-i2rs-cu-separation-info-model-01].



























Gu & Hu                  Expires January 3, 2018                [Page 6]


Internet-Draft       C/U Separated BNG Architecture            July 2017


   +-------------------+
   |                   |
   |       Internet    |
   |                   |
   +---------^---------+
             |
         +---+---+
         |       |              +------------------------+
         |   CR  |              |                        |
         |       |              |            +--------+  |
         +---^---+              |     +------+ Radius |  |
             |                  |     |      +--------+  |
             |                  |  +--+---+              |
         +---+---+              |  |      |  +--------+  |
         |       +--------------+  |      +--+  DHCP  |  |
         | BNG-UP+--------------+  | BNG  |  +--------+  |
         |       +--------------+  | -cp  |              |
         +---^---+              |  |      |  +--------+  |
             |                  |  |      +--+   EMS  |  |
             |                  |  |      |  +--------+  |
         +---+---+              |  +--+---+              |
         |       |              |     |      +--------+  |
         |  OLT  |              |     +------+  MANO  |  |
         |       |              |            +--------+  |
         +---^---+              |   Management|Network   |
             |                  +------------------------+
         +---+---+
         |  USER |
         +-------+

                       Figure 3: User Dialup process

   In the C/U seprated BNG architecture, there are several processes
   when a home user accesses the Internet.

   (1)User dialup packets of PPPoE or IPoE from BNG-UP which will send
   to BNG-CP from BNG-UP's Service Interface.

   (2)BNG-CP processes the dialup packet.  Confirming with the outside
   neighboring systems in the management network, BNG-CP makes the
   decision to permit or deny of the dial through certification.

   (3)After that, BNG-CP tells UP to do the responding forwarding
   actions with related policies.

   (4)If the user is certificated and permitted, the UP forwards the
   traffic into the Internet with related policies such as limited




Gu & Hu                  Expires January 3, 2018                [Page 7]


Internet-Draft       C/U Separated BNG Architecture            July 2017


   bandwidth, etc.  Otherwise, the user is denied to access the
   Internet.

6.  Advantages of C/U seperated BNG

   Due to the bandnew C/U separated BNG architecture, there are a lot of
   brilliant advantages.

   (1)Resources can be central controlled and balanced

   Centralized control plane takes the responsibility of control and
   management.  Thus it has the overall view of resources and can
   distribute the resources as required.

   (2)Device can be more efficient in extension

   Control plane and user plane can be extended separately according to
   different situations such as the session overload and extremely high
   throughput.

   (3)Management can be much easier as the BNG-CP is the only one facing
   to the outside system such as EMS, DHCP server, Radius and so on.

   (4)BNG-CP can be virtualized as a VNF with its management of MANO.

   (5)BNG-UP can be a virtual machine or physical device as demand.

7.  Security Considerations

   None.

8.  IANA Considerations

   None.

9.  Normative References

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

   [RFC2234]  Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
              Specifications: ABNF", RFC 2234, DOI 10.17487/RFC2234,
              November 1997, <http://www.rfc-editor.org/info/rfc2234>.






Gu & Hu                  Expires January 3, 2018                [Page 8]


Internet-Draft       C/U Separated BNG Architecture            July 2017


Authors' Addresses

   Rong Gu
   China Mobile
   32 Xuanwumen West Ave, Xicheng District
   Beijing, Beijing  100053
   China

   Email: gurong_cmcc@outlook.com


   Shujun Hu
   China Mobile
   32 Xuanwumen West Ave, Xicheng District
   Beijing, Beijing  100053
   China

   Email: hushujun@chinamobile.com.com

































Gu & Hu                  Expires January 3, 2018                [Page 9]


Html markup produced by rfcmarkup 1.129d, available from https://tools.ietf.org/tools/rfcmarkup/