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Versions: 00

CCAMP Working Group                                        J. Zhang, Ed.
Internet-Draft                                               Z. Liu, Ed.
Intended status: Informational                                Y. Ji, Ed.
Expires: December 18, 2019                                          bupt
                                                           June 16, 2019


 An Unified Control Plane Architecture for the convergency of radio and
                            optical networks
               draft-zhang-ccamp-radio-optical-control-00

Abstract

   This memo specifies an unified radio and optical control architecture
   based on Software Defined Networking (SDN).  The architecture is
   designed for the purposes of end-to-end 5G Radio Access Networks
   (RAN) service, which enables joint radio and optical network resoures
   orchestration.  Based on this architecture, some new applications
   could be achieved, such as enhanced Coordinated MultiPoint (eCoMP)
   service, Baseband Unit (BBU) aggregation, fronthaul traffic
   prediction and so on.

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/.

   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 December 18, 2019.

Copyright Notice

   Copyright (c) 2019 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
   (https://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents



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

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Requirements Language . . . . . . . . . . . . . . . . . . . .   2
   3.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Motivation and Goals  . . . . . . . . . . . . . . . . . . . .   4
     4.1.  BBU aggregation . . . . . . . . . . . . . . . . . . . . .   4
     4.2.  eCoMP . . . . . . . . . . . . . . . . . . . . . . . . . .   4
     4.3.  fronthaul traffic prediction  . . . . . . . . . . . . . .   5
   5.  Overview of Radio and Optical Network Control Architecture  .   5
   6.  Architectural Considerations of  Radio and Optical Control  .   7
     6.1.  Interface of Control Architecture . . . . . . . . . . . .   7
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   8.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .   7
   9.  Contributors  . . . . . . . . . . . . . . . . . . . . . . . .   7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   7

1.  Introduction

   This memo introduces an unified radio and optical network control
   architecture based on the Software-Defined Networking (SDN).  The
   architecture consists of three planes: application plane, control
   plane, and data plane.  For data plane, each physical node of radio
   and optical networks (i.e., BBU, RRU, and optical transport node) is
   attached with an OpenFlow agent (OF-Agent) that communicates with the
   OpenFlow controller through the extended OpenFlow protocols (OFP).
   For the control plane, it realizes the control of the physical
   devises,such as configuration of optical/radio network nodes and the
   information collection of network statuses.  In addition, the control
   plane realizes radio and optical resources virtualization, and
   performs joint resourses allocation (orchestration).The application
   plane consists of various services, and each service injects a policy
   rule to the control plane for orchestrating radio and optical
   resources.

2.  Requirements Language

   The key words are "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL
   NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL".






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3.  Terminology

   This memo uses the following terms: SDN, BBU, RRU, Service,
   Interface, Control.

   This document uses the following terms:

   OpenFlow Agent (OF-A): is associated with a physical node to
   communicates with the controller through extended OpenFlow protocol
   (OFP).

   Radio-Controller (Radio-C): is used to control wireless network
   devices.

   Transport-Controller (Transport-C): is used to control optical
   network devices.

   Resource Maintenance (RM): is to collect and maintain physical
   resource information.

   Protocol Control (PC): is to code/decode extended OF messages.

   Integrated Traffic Engineering Database (Integrated-TED): is a
   database to store virtualized radio and optical resources which are
   abstracted from raw physical resources.

   Virtual Optical Resource (VOR): abstracts the raw data of optical
   physical network which are reported from the RM module.

   Virtual Radio Resource (VRR): abstracts the raw data of radio
   physical network which are reported from the RM module.

   Orchestrator Engine: is an execution module which has two
   functions,lightpath management and radio resource mapping.

   Lightpath Calculation(LPC): is used to establish lightpaths for the
   connections .

   Radio Resource Mapping(RRM): is responsible for mapping RRU-BBU pairs
   .

   Policy Injection: the scheduling scheme for eCoMP , BBU aggregation
   scheme and fronthaul traffic prediction could be running in it.

   South Bound Interface (SBI): the interface between control plane and
   data plane.





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   Noth Bound Interface (NBI): the interface between application plane
   and control plane.

4.  Motivation and Goals

   The radio access network (RAN) architecture towards mobile 5G and
   beyond is undergoing a fundamental evolution, which brings optics
   into the radio world.  Fronthaul is a new segment that leverages on
   the advantages of optical communication for RAN.  However, the
   current fronthaul architecture shows a fixed connection between an
   RRU and a BBU, which leads to inefficient resource utilization.In
   addition, the existing network control architectures of radio and
   optical networks are built independently, where the convergence of
   radio and optical networks is inefficient in terms of end-to-end
   delay and joint resources allocation.  Therefore,to provide a good
   RAN performance, an unified control plane architecture for radio and
   optical networks SHOULD be proposed.

   SDN is an emerging paradigm that promises to change this state of
   affairs, by breaking vertical integration, separating the network's
   control logic from the underlying devices, promoting (logical)
   centralization of network control, and introducing the ability to
   program the network.  SDN makes it easier to create and introduce new
   abstractions in networking, simplifying network management,
   especially for the convergence of different network pardigms.

   Based on the advantages of SDN, we have established an radio and
   optical control architecture to achieve new applications, such as
   eCoMP service, BBU aggregation, and fronthaul traffic prediction,
   which are shown as follows.

4.1.  BBU aggregation

   BBU aggregation is to turn off the low-utilized BBUs and migrate
   their RRUs to other active BBUs through lightpath reconfiguration.
   With the help of BBU aggregation, BBU resource utilization can be
   significantly improved, and this is enabled through the unified radio
   and optical networks control architecture.

4.2.  eCoMP

   The eCoMP exploits the fronthaul flexibility by dynamically
   reconfiguring the lightpath between RRUs and BBUs, which is to
   reassociate coordinated RRUs (connected to different BBUs) within a
   single BBU.  With the help of eCoMP, several geographically-adjacent
   RRUs jointly process/transmit as a single antenna system that serves
   for the cell-edge users.It realizes the backhaul bandwidth saving
   between the coordinated BBUs.



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4.3.  fronthaul traffic prediction

   The date rate of new fronthaul interfaces, such as eCPRI and NGFI
   CPRI, are depending on the wireless traffic load.  Therefore, the
   wireless traffic prediction is an important thing to improve the
   fronthaul bandwidth utilization.  It could be predicted by using
   machine learning approach to perceive user's behavior (e.g.,traffic
   load, mobility), which can be enabled by this unified control
   architecture.

5.  Overview of Radio and Optical Network Control Architecture








































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     o-----------------------------------------------------------------o
     | +------+      +-----------------+       +-------------------+   |
     | |eCoMP |      | BBU Aggregation | ...   |Traffic Prediction |   |
     | +------+      +-----------------+       +-------------------+   |
     |                 Application    Plane                            |
     o----------------------------|------------------------------------o
                                  |North Bound Interface (NBI)
                                  |
     o----------------------------Y------------------------------------o
     |                    +----------------------+                     |
     |                    |   Policy Injection   |                     |
     |                    +------Y-----------Y---+                     |
     |              -------------|           |------------             |
     |              |                                    |             |
     |   +----------Y----------+             +-----------Y----------+  |
     |   |    Inergrated TED   |             | Orchestrator Engine  |  |
     |   |    ----     ----    |             |   ----      ----     |  |
     |   |   |VOR |   |VRR |   Y-------------Y  | LPC|    | RRM|    |  |
     |   |    ----     ----    |             |   ----      ----     |  |
     |   +----------Y----------+             +----------Y-----------+  |
     |              |                                   |              |
     |   +----------Y----------+             +----------Y-----------+  |
     |   | Transport Controller|             |   Radio  Controller  |  |
     |   |    ----     ----    |             |    ----     ----     |  |
     |   |   |VOR |   |VRR |   |             |   |VOR |   |VRR |    |  |
     |   |    ----      ----   |             |    ----     ----     |  |
     |   +---------------------+             +----------------------+  |
     |                                                                 |
     |                    Control     Plane                            |
     o----------------------------|------------------------------------o
                                  | South Bound Interface (SBI)
                                  |
     o----------------------------Y------------------------------------o
     |                                                                 |
     |   +-------Y------+     +-------Y------+    +--------Y-------+   |
     |   |  RRU_Agent   |     |   BBU_Agent  |    |    TN_Agent    |   |
     |   +--------------+     +--------------+    +----------------+   |
     |                         Data    Plane                           |
     o-----------------------------------------------------------------o

   Figure 1: Unified Radio and Optical Control Architecture based on SDN

   The framework of SDN-enabled control architecture is consisting of
   three planess: application plane, control plane, and data plane, are
   interconnected via a northbound interface (NBI) and a southbound
   interface (SBI).  For data plane, each physical node (i.e., BBU, RRU,
   and TN) is attached with an OpenFlow agent that communicates with the
   controller through extended OpenFlow protocols (OFP).



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   The control plane is consisting of five modules: Policy Injection
   module, Optical-Controller (Optical-C) module, Radio-Controller
   (Radio-C) module, and Integrated Traffic Engineering Database
   (Integrated-TED) module.  Policy Injection (eCoMP) runs application
   policies, such as the eCoMP algorithm, BBU aggregration.  Radio-
   Controller (Radio-C) is used to control radio devices.  Optical-
   Controller (Optical-C) is used to control optical devices.
   Integrated Traffic Engineering Database (Integrated-TED) is a
   database to store virtualized radio and optical resources which are
   abstracted from raw physical resources.

   The application layer includes some applications implemented in the
   framework of SDN-enabled control architecture, such as eCoMP, BBU
   aggregation, traffic prediction and so on.

6.  Architectural Considerations of Radio and Optical Control

6.1.  Interface of Control Architecture

   SBI:In radio and optical control architecture, control plane and data
   plane are interconnected via SBI.  Existing SBI includes: NETCONF,
   OpenFlow, SNMP, OpenCONFIG, PCEP, et al.

   NBI:In radio and optical control architecture, application plane and
   control plane are interconnected via NBI.  The NBI is mainly REST
   API.

7.  Security Considerations

8.  Acknowledgments

9.  Contributors

Authors' Addresses

   Jiawei Zhang (editor)
   Beijing University of Posts and Telecommunications
   Xitucheng Road
   Beijing, Haidian District  100876
   China

   Phone: +86-010-61198422
   Email: zjw@bupt.edu.cn








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   Zhen Liu (editor)
   Beijing University of Posts and Telecommunications
   Xitucheng Road
   Beijing, Haidian District  100876
   China

   Phone: +86-010-61198422
   Email: liuzhen207@bupt.edu.cn


   Yuefeng Ji (editor)
   Beijing University of Posts and Telecommunications
   Xitucheng Road
   Beijing, Haidian District  100876
   China

   Phone: +86-010-61198422
   Email: jyf@bupt.edu.cn

































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