NTT Access Network Service Systems Laboratories are developing virtualization functions of optical access systems and so have advanced Open Source Software (OSS) for SDN-Enabled Broadband Access (SEBA).
Optical access systems mainly target the provision of Fiber To The Home (FTTH) services which connect subscribers’ homes to central offices. However, recent applications being studied are intended to connect mobile antennas and central offices, and for various services such as factory / university LANs. To date, since optical access systems have been redesigned for individual services and the detailed specifications depend on access technologies and vendors, it is necessary to not only develop transmission devices such as Optical Line Terminal (OLT) but also the Operation Support System (OSS) of the network operator on a large scale for providing new services. This is because the transmission function and control function are tightly coupled in the conventional optical access systems. In order to solve this problem, the application of network virtualization technology to the optical access system is being advanced.
Open Networking Foundation (ONF), which is an OSS community, is driving the development of SEBA, a platform that realizes virtualization of various optical access systems (Fig. 1). SEBA is mainly composed of Virtual OLT Hardware Abstraction (VOLTHA), Open Network OS (ONOS), and Network Edge Mediator (NEM). VOLTHA is software designed to realize abstraction functions and provides common management interfaces for various access technologies and vendor specifications. VOLTHA is controlled via ONOS, which is an OpenFlow controller, and NEM, which converts input information from OSS to forms that can be interpreted as subordinate components. Development of this software is still in progress as of December 2020, and verifications according to the operator's workflow and improvements in software stability are being conducted.
Figure 1. Architecture of SEBA. (ASG: Aggregation and Service Gateway)
Abstract
ITU-T standard and IEEE standard are globally utilized as prime optical access technologies. NTT Access Network Service Systems Laboratories are actively contributing to SEBA by implementing abstraction functions to support the IEEE specification for VOLTHA and NEM. In particular, we defined the setting file for IEEE-specification VOLTHA and abstracted access technology by implementing a read function and a hardware setting function (Contribution 1). In addition, we abstracted the authentication method by implementing IEEE-specification authentication workflow (Contribution 2). Contributions 1 and 2 are described in detail on the following pages.
Table 1.　Released software.
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Contribution
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URL of software |
Release date |
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1. setting file and read function for IEEE specification |
June, 2020
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1. OLT hardware setting function for IEEE specification |
December, 2020
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1. ONU hardware setting function for IEEE specification |
December, 2020
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2. Authentication workflow for IEEE specification |
December, 2020
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Further plans
We are studying specific applications and trials.
- Contribution 1: Abstraction of access technology
- Contribution 2: Abstraction of authentication method
 TOP |
 1.Main Functions and technical points |