Optical network virtualization is facing technical difficulties

Since 2014, optical network research and application virtualization technology the industry has been widespread attention, including ZTE, ADVA, Huawei and other manufacturers will deploy the next generation of optical networks "to support optical network virtualization SDON system" as the optical network services technology focus on the development. Optical network resources as a basis for data center interconnect, and virtualized application scenarios it is generally considered to greatly simplify network operators work.

Each data center has its own specific QoS and SLA requirements, network operators need a dedicated OTN network through a virtual optical network based on a shared unified physical OTN network equipment on, to meet different business needs. Currently, optical network virtualization faces many technical difficulties. mainly include:

1, how to provide scalable, flexible and configurable network application services, including: across multiple management domains to achieve the end service connection and OVPN control; how to provide dynamic connectivity services, namely BoD service according to user requests; How-end connections to ensure low jitter, low latency QoS; how coordination between network resources, such as CPU, memory and visual display equipment.

2, the optical network resources to achieve abstract package, namely how the optical network physical layer resource model abstract mathematical model of extraction, in particular resource and the need to consider the optical network transmission mode has its own physical characteristics restrictions, such as different from physical to other networks floor loss: to the accumulation of a variety of physical layer optical channel impairments of optical signal transmission own characteristics, dispersion and gain jitter, etc., how these optical network physical layer to the optical loss to abstract virtual layer.

3, virtualized optical network resource mapping to physical resources required for the issue of virtual nodes and virtual link virtual optical network services VONS distribution of run-time, designed to solve the objective function (such as infrastructure resource mapping assignments for different optimization strategies load balancing, maximizing network currency earnings, quality of service can be optimized to maximize the amount of end-users, etc.), optimization model and optimization algorithms to meet individual performance, benefits and other needs of the user optical network. Optical network virtualization technology research long way to go, but it can bring the value is immeasurable, represents the forward direction SDON technology development, with its focus on the extent and depth of research continues to improve, I believe that in the near future will leap of progress in implementation.

Optical network virtualization

With the deepening of SDON technology research, industry and gradually discover Optical Network virtualization is a major part of the basis and premise-based open control SDON also SDON inside the controller can not be missing. For SDON technology, network virtualization is an important part of the support network of diverse structures, network architecture supports simultaneous multi-carrier presence. It supports a range of open programmable network interface and create a virtual abstraction layer for the network physical layer device. Abstraction layer allows the user to control and change the appropriate network status, and shields the user from the physical layer of the network operation and use complex, allowing users to deploy new applications more easily on an abstract level, thereby enhancing application flexibility.

The main difference SDON in network virtualization and broad network virtualization is the ability to virtualize the subject. Often, people think SDN data network capabilities from a single, isolated disparate hardware platforms, and in the form of a virtual machine to manage these components. The SDON Network virtualization will make these simplifications, generalization. For example: Shielded physical plane details and automate planning, configuration, management, optimization and protection and restoration. Manual processes and planning processes also to the evolution of virtualization, automation and increased flexibility enables operators to reduce high-level workloads, placing the lower level, including optoelectronics levels.

In SDON architecture system, optical network virtualization main aims: the physical layer of optical network infrastructure virtualization, and then complete the optical network services abstraction and encapsulation, services and physical layer network infrastructure will provide separation , for the upper user programmable, definable virtual layer optical networks. Can have a profound impact on the future development of optical networks, operators can pass to an open application layer user interface, the optical network infrastructure control to the application layer user. According to the user's level of competence, some or all of the network resources open virtual layer optical networks, allowing users to virtual optical network resources available on the basis, according to their need for access and control - allows users to integrate their own definition of network resources to achieve "The optical network resources as a service" technology concept OAAS of.

SDON technology advantages and characteristics

SDON technology has three major advantages. First, it can effectively solve the interconnection between heterogeneous networks. Through OpenFlow and other related agreements to expand the development of object-oriented interactive control interface enables heterogeneous network information abstraction and cross-layer network control integration, resulting in the access network and the core network, data networks and optical networks, cable networks and between the radio network set up with a unified control system of the new heterogeneous network architectures. Second, the arrangement of optical network to meet user needs. For flexibility in the use of network equipment, operations and sales, and it enables users to faster achieve the desired services. Third, SDON can bring optical network resource virtualization management. It can cover the entire range of network equipment OTN products to better play the advantages of network infrastructure resources, through open unified resource management platform that allows the use of network resources optimized. It features multi-domain SDON aspect of hierarchical control architecture mainly as follows:

1, the whole structure is divided into four levels: APP application layer, Orchestrator total control layer, single domain controller layer, and Optical Network device layer.

2, NBI focus APP application layer interfaces with Orchestrator total controller uses Restful interface mechanism. Restful mechanism architectural style draws WEB services, with no state, to achieve simple and efficient, loosely coupled, scalable and other technical advantages, so as to achieve open control SDON of NBI, programmable, definable and other technical characteristics, provides a natural technology support.

3, SBI interfaces single domain controller layer and between the layers of optical networking equipment and OTN networks as much as possible compatible WASON earlier deployed to ensure network interoperability SDON these network devices, better meet the smooth deployment of business operators upgrade, gradual evolution of ideas.