ZTE E-OTN End-to-End Solution: All-Optical Bearing and Superspeed Interconnection

Updated:2017/6/23 17:33

The development of big video and 5G will lead to hundredfold even thousandfold increase in the demand for network bandwidth. With the 2 M home bandwidth gone, the big-video and 5G era features 100 Mb and even 1000 Mb access. The access bandwidth for 4K videos on a single 4K terminal, for example, is more than 50 Mbps. Even at the beginning of big-video deployment, the OLT uplink bandwidth will be 2 × 10 Gbps calculated according to 15% of the 4K market penetration. With the development of the big video service, the bandwidth demand will increase by 5 to 20 times and the OLT uplink bandwidth will reach 100 Gbps. In addition, superb video experience means a low packet loss rate and a low delay; however, traditional "direct fiber driving" and packet transport networks cannot satisfy this stringent requirement. A new solution becomes a need for efficient bearing in the big-video era.

Compared with 4G, the base station density, spectral efficiency, and spectrum width of 5G are greatly improved, resulting in the growth of the demand for 5G network bandwidth by dozens of and even hundreds of times. In some application scenarios, such as Internet of Vehicles and Telemedicine, the end-to-end delay in the transfer from the base station to the transport network of the core network cannot be more than 200 ?s, which means that the network architecture must be changed. High bandwidth, low delay, and high reliability are the core requirements for the development of new services, which can be met by the construction of an end-to-end all-optical transport network, implementing all-optical bearing for all services.

E-OTN, Leader of the OTN Era

The early OTNs were used to provide large-capacity pipelines for the MAN core layer or long-haul backbone layer. However, to match the requirements for high bandwidth, low delay, and high reliability of new services, the OTN networks inevitably extend from the core backbone layer to the access and convergence layers, realizing end-to-end bearing of the video, radio, and dedicated government and enterprise line services in a unified way.

With the convergence of the IT and CT, virtualization will become the evolution direction of communication networks. In the reconstruction process of Central Offices (COs), OTNs need to extend to the COs to implement the interconnection of the vDCs at all levels. However, the dedicated OTNs and virtualized DCs can implement network collaboration and improve the resource utilization only through unified management. Therefore, based on the large-capacity rigid pipelines, the OTNs need to implement the flexible small-granularity service bearing and support the SDN network architecture, achieving unified management between the SDN and vDCs and making the network architecture more elastic.

To enhance the capability of OTN deployment for the future all-optical transport networks, OTN devices should be environmentally friendly, energy saving, easy to install, easy to deploy, service-encrypted, and extremely simple to operate and maintain.

To address the challenges, ZTE offers the integrated E-OTN end-to-end solution to match the development of new services and the evolution of networks, help operators build end-to-end all-optical transport networks, and realize unified multi-service bearing.

End-to-End OTN

End-to-end OTN deployment is the inevitable trend of network development. The ZTE E-OTN product series includes the ultra-large capacity packet OTN devices ZXONE 9700 & ZXONE 8700 and the compact OTN device ZXMP M721 used in the access and convergence layers. The two devices can cover all the application scenarios from the access and convergence layers to the core backbone layer, and build end-to-end all-optical pipelines.

End-to-end OTN deployment makes the network planning and operation management of operators more difficult. ZTE E-OTN provides a network-wide planning tool Top510 to achieve fast planning for end-to-end E-OTN services. The unified Element Management System (EMS) U31 provides service view functions to enable fast provisioning of end-to-end services, rapid location of faults, and unified management of devices. In a word, ZTE E-OTN provides not only OTN devices for different layers but also the means for unified end-to-end planning, management, and operation and maintenance.

Elastic OTN

In the context of ICT convergence, NFV-based telecom network virtualization and the reconstruction of COs into vDC are much discussed among operators. There is a popular view in the industry that the future networks will be vDC-centric and large-capacity OTNs provide high-speed interconnection pipelines to realize collaborative "IP + optical" scheduling. To realize this network, the OTN must implement two functions.

For an OTN device, the original ODU0 granularity seems too big to increase the network resource utilization, and small-granularity services cannot be efficiently scheduled due to the rigid pipelines. OTN devices must, therefore, elastically carry small-granularity services based on the rigid pipelines. It can be said that the Elastic OTN is the inevitable direction of the future OTNs. By using the universal IE exchange technology, ZTE E-OTN achieves unified cross-connection of ODUK/PKT/VC and efficient elastic bearing with rigid pipelines.

For the network architecture, the future network manages vDCs and OTNs in a unified way by using the SDN technology. Therefore, the OTN must support the SDN technology, and implement rapid function reconstruction based on the unified orchestration layer controller, making the network architecture more flexible to follow the development trend of the SDN/NFV technology.

ZTE E-OTN takes the lead in the Software Defined Optical Network (SDON) technology in the industry and has been put into pre-commercial use many times. By 2016, ZTE had worked together with many Chinese and international operators, such as China Mobile, China Telecom, China Unicom, and Vodafone, in the E-OTN SDON field and launched pre-commercial use in the existing networks.


Figure 1 Feature-Oriented OTN Architecture

Enhanced OTN

The ZTE E-OTN solution meets the development trend of networks and focuses more on the real benefits of operators. To solve the problems in the existing operators' networks, such as power consumption, equipment rooms, and operation and maintenance, the ZTE E-OTN solution provides some new technologies to enhance the deployment capacity of OTNs equipment.

With the increase of the electric cross-connection capacity of OTN devices, the power consumption rapidly rises, seriously restricting actual OTN deployment. Therefore, an all-optical transport network cannot be successfully deployed without the effective consumption reduction measures. Therefore, the ZTE E-OTN solution provides multiple consumption reduction schemes in the following aspects:

Optical modules: By using the silicon-based optical integration technology, all original optical module-related components are integrated on the same silicon substrate, reducing the volume of the optical modules and greatly reducing power consumption.

Core chips: Based on ZTE's investment in the microelectronics technology, the E-OTN uses a large number of self-developed high-performance chips, for example, the new 16 nm chip developed by ZTE Microelectronics with more-powerful functions and lower power consumption.

Overall heat dissipation: With the optimized cooling air ducts in the cabinet, hot and cold air cannot be mixed in the E-OTN, thus improving the heat efficiency, reducing the fan speed, and decreasing the power consumption for long time operation.

Hybrid photoelectric cross-connection application: The application of optical cross-connection technology can greatly reduce the power consumption of the whole network. Combined with electrical cross-connection, the hybrid cross-connection technology can achieve not only flexible service scheduling but also power consumption reduction of the whole network, conducive to the long-term evolution of networks.

As described above, the optical cross-connection technology is the key to large-capacity service scheduling and power consumption reduction of the whole network in the future. In addition, to meet the requirements for the ultra-low delay of new services, the number of electric layer processing attempts in an end-to-end OTN should be as small as possible to connect directly in the optical layer. Therefore, the optical cross-connection technology becomes the first choice for node scheduling in an all-optical network. The main solution to optical cross connection is the Reconfigurable Optical Add-Drop Multiplexer (ROADM). ROADM, since it was first launched, has been labeled as the technology with complex fiber connection and troublesome maintenance. Especially with the increase of the ROADM dimension and the large-scale application of the CDC ROADM technology, improving maintainability of ROADM becomes the key to the commercial deployment of the optical cross-connection technology. To solve the common problems, ZTE developed the new "optical backplane" technology; more specifically, the tail fibers in the ROADM are integrated into the optical backplane, freeing operators' maintainers from complex fiber connection and paving the way for the wide application of the hybrid photoelectric cross-connection technology.

ZTE E-OTN Product Family and Global Application

Figure 2 shows the products in the ZTE E-OTN family.

M721: small OTN device used in the convergence and access layers. It supports several subracks. The DX61/62/63 is a small distributed electrical cross-connection subrack with the heights of 1U, 2U, and 3U. It can carry multiple services due to its easy deployment. The CX66A is a centralized electrical cross-connection subrack. It supports an electrical cross-connection capacity of 1 Tbps and the SDON and ROADM functions.

ZXONE 9700 and ZXONE 8700: large-capacity OTN devices used in the core backbone layer, supporting 100 G OTN. The ZXONE 9700 can support even 400 G OTN with the largest cross-connection capacity up to 28.8 Tbps, meeting the demand of operators for large-capacity electrical cross-connection.

The preceding E-OTN devices cover all the application scenarios from the access and convergence layers to the core backbone layer, implementing end-to-end OTN deployment.


Figure 2 ZTE E-OTN Product Family

As a world-leading telecom equipment manufacturer and solution provider, ZTE holds an important position in the global telecom industry. According to the latest report from OVUM, a famous consultancy firm, ZTE is one of the world's major OTN equipment suppliers with the second-ranked market share of its OTN equipment in the world.

In this era with constantly emerging new services, the launch of the E-OTN solution follows the direction of network evolution in the future. The end-to-end OTN solution can provide large-capacity and low-delay pipelines and therefore is the inevitable choice of operators to implement 5G and big-video deployment. The elastic OTN platform can provide elastic bearing of small-granularity services, improving the utilization of network bandwidth. The enhanced OTN device achieves a great leap in power consumption reduction and energy saving, significantly reducing the OPEX of operators. Reflecting the development direction of OTN, the launch of the E-OTN solution not only follows the trend of network transformation, but also resolves the problems for operators.

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