Building Service-Oriented Optical Transport Networks

The emergence of new telecoms services has had an impact on the requirements for transport networks, which have been forced to evolve in order to keep pace with new applications and initiatives.

In light of emerging 3G, IPTV and NGN technologies, the challenge of developing network architecture and transforming the pure traditional service operation mode to deliver new services for customers, has become a prime concern for operators. The traditional transport network can no longer satisfy the requirements for development of new services meaning that the migration of transport networks to service networks is an inevitable trend.

The development of new services brings unprecedented opportunities and challenges to the optical network market. The maturing of new technologies such as resilient packet ring (RPR), multi-protocol label switching (MPLS), automatically switched optical network (ASON) and reconfigurable optical add/drop multiplexer (ROADM), enables the construction of new generation optical network technology incoprporating large capacity, high speed, intelligence and multi-service provision capability. Backed up by a strong R&D team, ZTE continues to pioneer advanced solutions to provide perfect-fit services for customers.

ZTE´s 3G service solution

ZTE´s 3G service offers a high degree of diversity. The intermittent nature of data services means that the 3G access layer needs to provide abundant interface types, a high bandwidth utilisation ratio and large-capacity access capabilities. With the increasing customer demand for service security, next generation network solutions need to provide QoS guarantees as well as protection and restore modes for different services.

ZTE has been devoted to optical network technology research for years and has successfully launched its Unitrans series of optical equipment based on innovative R&D designs and application successes. The Unitrans ZXMP S390/S385/S380/S330/S320 range of equipment can provide bandwidth from between 10G to 2M in addition to rich application interfaces. Data services can be processed intelligently with embedded RPR and MPLS to reduce arduous manual configurations and dispatching. In this way, data services can be delivered rapidly and flexibly, where bandwidth is shared fairly and adjusted according to specific demands, thereby greatly improving network transport efficiency.

For convergence and core layer networks, the basic requirements are large-capacity and high QoS. In light of the trend of convergence in communications services, networks are destined to become ever larger as they rise to the applications challenge. Built on achievements from years of R&D, ZTE has made a significant breakthrough in DWDM large-capacity transmission techniques and has seen its products deployed commercially worldwide.

ZTE´s ZXWM M900 solution incorporates industry-leading technologies including the high power erbium-doped fiber amplifier (EDFA), a remotely pumped optical amplifier (RPOA), enhanced forward error correction (FEC), code pattern modulation, self-adaptive receiving, wavelength tuning, centralised wavelength control, intelligent power management and distributed dispersion management. These enhancements mean that it has sufficient capacity to solve wavelength stability issues, signal-to-noise ratio (SNR) and problems arising in large-capacity long-haul transmission. It can realise single span transmission over a distance of 300km as well as super long-haul non-REG transmission over 5000km, thereby greatly reducing the expenses for regenerator construction and maintenance while also guaranteeing security and reliability in the network. 

ZTE´s IPTV service

The IPTV service network consists of a content distribution network (CDN) and a customer operation support system. The CDN is composed of DSLAMs and a video broadcast system, providing high bandwidth and assured service quality. The principal service units of CDN include a live broadcast server, a streaming media server, a broadband access server (BAS) and DSLAM supporting the multicast media stream. The CDN may be regarded as a two-layer network; the live broadcast server, stream media server and BAS comprising the first layer, and the elements between the BAS and DSLAM as the second layer. The DSLAM is critical in CDN construction since it is widely deployed and handles high-speed digital data streams generated by numerous customers.

The DSLAM supports IPTV multicast, VoD, Internet service, videoconferencing and the long-distance learning service with applied bandwidth from 400M to 600M.

To ensure the QoS of transmitting the IPTV service, a special connection from BAS to DSLAM is required. With ZTE´s embedded RPR technology, the service can be delivered rapidly -- access nodes can be increased without adding network bandwidth and fast-forwarding can be offered in an end-to-end scenario to guarantee the QoS for the multicast service.

In addition, the embedded RPR handles traffic according to priorities specified by class to ensure fair bandwidth access to ring resources, thus accomplishing integrated transmission of IPTV, Internet data and operation support information. It provides carrier-class operation, maintenance and management to guarantee the long-term stability and operation of IPTV service transmissions.

Building the new generation optical network

ZTE has developed its optical network solution with the two most important elements of new generation networks in mind; multi-service applications and an intelligent transport network. The SDH evolves towards MSTP for delivering multiple services while GMPLS/ASON control plane is used to realise flexible bandwidth allocation, automatic end-to-end service dispatch and dynamic protection and restore functions. With the development of new services, wavelength multiplexing technologies should support the rapid access of multiple services and optical layer protection in addition to promoting the roll-out of large-capacity, high bandwidth transparent services. 

ZTE has also taken an active part in developing international optical network standards while actively cooperating with various operators after careful market related study. In terms of lowering network construction costs and enhancing network operation efficiency, ZTE´s new generation transport network is able to provide a range of new service network solutions for operators, allowing them to meet the challenges they face from the rapidly changing communications environment.

ZTE was authorised to construct multiple major network projects around the world in 2005, in countries including Bulgaria (a Cabletel national backbone transmission network), Romania (Euroweb national backbone transmission network), Nigeria (NITEL national backbone transmission network), Pakistan (PTCL-OFAN optical access project), Macedonia (national backbone transmission network) and Venezuela (national optical fiber network project).

These deployments are proof that ZTE´s technology offering has won wide customer approval. "Over the years that the ITU and ZTE have been working together, ZTE has clearly demonstrated its technical expertise and extraordinary dedication to research and development," said Mr. Zhao Houlin, Director of Telecom Standardisation Bureau of ITU at the 2005 ITU meeting in Geneva.

BSNL, the largest national telecommunications operator in India, has benefited first hand from ZTE´s knowledge and experience. Following the successful completion of the first phase of a national backbone network carried for the operator, ZTE was authorised to build the project´s second phase. ZTE´s ability to deliver on the project was recognised personally in a letter to ZTE from Mr S. Sridhar, Joint Deputy Director General for BSNL.

ZTE is becoming the fastest growing supplier of optical transport equipment in the world. Its growing importance to the global optical network market is manifested in the active role played by it. ZTE optical networks have been deployed in approximately 70 countries and regions around the world so far.