E-MSTP-Efficient, agile and compatible solution to mobile transport network

As telecoms networks are developing towards packet-based and broadband-based, IP-based service network is the inevitable trend in future evolution. The bearing mode of 3G mobile network tend to evolve from ATM bearing to IP bearing during its version evolution from R4, R5 to R6.

The core network, with separate circuit domain and packet domain, uses MSC Server and IP router to implement IP bearing and switching of voice, data, image and multimedia services; the ever-increasing router capacity and port rate need big granularity for core network link service , all these above drive the transport network to develop toward IP+Wavelength.

Compared with the core network which is obviously based on IP over WDM mode, the access network has more complicated network structures and transport technologies, and more construct expenditure. So, the most important problem of transport network construction is how to keep up with the IP-based trend, bear multiple services efficiently, and reduce construction and maintenance cost.

Bearing requirement analysis for radio access network

• Provide statistic multiplexing functions, satisfy high broadband requirement of 3G services

3G is experiencing continued increase in single user rate, pushing total bandwidth of base station up by folds, which poses higher demands for bandwidth in comparison with GSM base station. 3G networks will see their earliest deployments in major cites with developed economy and large population density, offering bandwidth of 8~20 E1s. Mobile data services drive the bandwidth requirement for 3G services. Traffic uncertainty and bursty features of data services necessitate the transport networks’ ability to converge and aggregate services, effectively utilize network bandwidth resources and save network construction investment.

• Demands on differentiated services

Rollout of diversified 3G services, including traditional voice services and HSDPA-enabling video sharing, online download and mobile advertisement services, helps operators achieve higher profit growth. How to exploit the limited resources to carry more services and maximize operational yield is the focal point of operators. Therefore, it requires transport network to offer intelligent service awareness and rational distribution of resources, thus providing differentiated services for different levels of services/customers.

• Requirement for high reliability and scalability

As transport network is the infrastructure network, Operators always put emphasis on its reliability. The transport network adopts carrier-class OAM and 50ms protection restoration mechanism, which give basic guarantee for the quality of 3G services and have direct impacts on final user experience. In initial 3G deployment, it is difficult to deploy network in one step. Increase of sites and changes in bandwidth planning necessitate transport network’s ability to scale as 3G grows.

• Converged evolution to protect investment

Transport network, as the infrastructure network, should grow with the development of service network. With ability to evolve forward, it can avoid overlapping network projects, protect operators’ investment and lower TCO.

Efficient, agile and compatible E-MSTP solution

Facing the requirements, which technology can facilitate carriage of 3G UTRAN services, and allow operators to accelerate 3G network deployment?

MSTP technology is mature. It takes pride in security, reliability and quality of service, and has been widely deployed in existing networks. But MSPT employs rigid pipeline to carry packet services, leading to limited convergence ratio and low statistic multiplexing efficiency. The attention-grabbing PTN technology is based on packet architecture. It leverages on MSTP concept, whilst incorporating the benefits of Ethernet and MPLS, and is the bearing technology fitting the carrier-class and packetized trend. Widespread deployment of PTN technology takes time due to technology debate, unsettled standards and immature industry chain, making it difficult to satisfy operators’ requirements for rapid rollout of 3G and all-service networks.

E-MSTP solution is emerging as a result, attracting the industry’s attentions. On basis of traditional MSTP platform, E-MSTP greatly enhances data service processing capability, realizes balanced carriage of TDM services and data services. Being efficient, agile and compatible, E-MSTP leverages existing MSTP bearing resources to accelerate rollout of network, fully accommodating various requirements of 3G bearing, whilst enabling converged evolution to PTN. It is the best solution that also protects investments.

E-MSTP solution has following features:

• Multi-protection to ensure the stability of 3G network

E-MSTP retains MSTP’s advantages to be highly reliable, stable and easy to manage. Aside from redundant protection for critical equipment boards, multiple protection modes, including SDH network-level protection, MAC layer Steering protection or Wrapping protection are available in E-MSTP. Combined use of these protection modes can offer 50ms switching time and carrier-class service quality of five nines.

E-MSTP’s intelligence feature makes it easy to detect fiber misconnection of fiber and protection inconsistency in the network, thus simplifying operation & maintenance. Multi-protection and intelligence of E-MSTP can greatly increase service network survivability and guarantee the stable operation of 3G network.

• Efficient statistic multiplexing capability to achieve value-added network bandwidth and maximize operators’ profit

Rollout of 3G HSDPA services brings huge bandwidth requirements. These data services are bursty and have high peak-to-average power ratio. Legacy MSTP employs rigid pipeline to carry data services, which is low in bearing efficiency, the transmission resources face the gigantic pressure as a result.

With RPR-embedded data processing unit, E-MSTP features efficient statistic multiplexing capability, and offers up to 2-5 times higher bandwidth utilization than typical MSTP. It can effectively utilize network bandwidth resources, save network construction investment and maximize operators’ profit.

E-MSTP statistic multiplexing capability

• Intelligent service awareness to offer differentiated services for diversified 3G services

3G uses IP DSCP to differentiate different service types. E-MSTP can automatically identify services based on IP DSCP. It classifies voice, narrowband video, game and session services with high priority as Class A, allowing high-quality transmission with bandwidth reservation, low latency and low jitter; streaming media services with latency insensitiveness and bandwidth guarantee are classified as Class B; Internet browsing, content download services are Class C best-effort service, performing bandwidth statistic multiplexing. Use of intelligent service awareness to offer differentiated services can effectively increase bandwidth utilization, as well as mitigate the impacts of Internet access and download services with high bandwidth requirements and bursty feature on major services.

E-MSTP service awareness capability

• Integrating intelligence to help operators accelerate 3G deployment

E-MSTP integrates intelligence, and supports real distributed access control. In this way, services can be added by only configuring source and sink nodes, eliminating the needs for node-by-node and circuit-by-circuit configuration, vastly simplifying service provisioning and accelerating rollout of 3G services.

In initial 3G deployment, it is difficult to deploy network in one step. Increase of sites and changes in bandwidth planning necessitate transport network’s ability to scale as 3G grows. E-MSTP supports auto-discovery of topology, new sites added on ring are non-service affecting, making it easy and rapid for network extension. E-MSTP provides bandwidth resource flexibility. With LCAS technology, the bandwidth can be increased without any impact on original services, allowing operators to implement flexible capacity expansion.

• Converged evolution to protect investment

E-MSTP can evolve to PTN network. As 3G evolves towards LTE, and operators tend to network flatness and fixed-mobile convergence (FMC), in some hot spot areas, E-MSTP networks can be optimized to PTN network. In this way, the overall network conducts converged evolution, and realizes unified network management and unified service scheduling step by step, resulting in lowered network transformation risk, reduced initial investment, whilst ensuring network continuity and inheritance.

Case study of ZTE E-MSTP

ZTE E-MSTP comprises series products, such as S325, S330 and S385, with rate ranging from 155M to 10G. ZTE E-MSTP products have been widely deployed in domestic and international markets, addressing operators’ requirements for end-to-end diversified applications. Major projects include Panama Optynex, Korea LG, China’s first commercial project-Xinjiang Karamay Oilfield transmission network project and China’s biggest commercial project-Qinghai-Tibet Railway video surveillance transmission network project. At the end of 2007, ZTE participated in “Research on development strategy for 3G all-service-oriented metro transport network” topic initiated by China Mobile Research Institute, and completed the test of 3G IP RAN services carried over E-MSTP. As China’s first test to simulate 3G network application environment in lab, the test used E-MSPT to carry 3G services, thus providing effective experimental data support for its viability and availability. In 2008, ZTE had in-depth cooperation with China Mobile and China Unicom, and successfully conducted Tianjin TD IP UTRAN-E-MSTP field trial and Fujian Quanzhou WCDMA IP UTRAN-E-MSTP field trial, fully demonstrating E-MSTP’s high transport efficiency, service awareness and intelligence under 3G live service environment, and offering field trial evidence for 3G transport network construction strategy.

ZTE received the prestigious Metro Network Technologies and Services Award for its efficient, agile and compatible E-MSTP solution at 2008 Broadband World Forum (BBWF), was awarded “China’s Best Optical Communication Solutions” at 2008 Optical Communications and Broadband Development Forum.