OTN Soft Capabilities Ensure End-to-End 4K Service Experience
4K has been years in the making, but only recently has it entered a mature stage on the supply chain. One after another, carriers around the world are formally releasing their own 4K services and related brands to meet requirements for optimal experience and foster new profit growth points, and 4K development is driving forward quicker than ever.
2016 is set to be the beginning of an era for large-scale 4K services. It is predicted that in 2016, the number of 4K video sources on the market will exceed 5000, and the percentage of video sources offering 4K will be as high as 80%.
Netflix in North America and some Japanese and Korean carriers have already opened testing channels for commercial 4K. In August 2016, BT will launch their UHD experience channel, providing seven channels for free webcast and 4K, as well as a 4K set-top box. In 2015, VFD Germany and DT announced their 4K service offering, which will be rolled out at the same time as reconstructing and optimizing their networks.
2 Requirements Placed on Bearer Networks by 4K Services
Bandwidth, latency, and packet loss together determine the effect of 4K experience. Based on estimates, between 2017 and 2019, resolution will reach 3840×2160, and the frame rate will reach 120 frames per second, requiring 75 Mbit/s bandwidth. In 2020, which is predicted to be the peak period for 4K, resolution is expected to reach 7680×4320, requiring an average bandwidth of 100 Mbit/s. In terms of network latency and packet loss, key indicators include fast loading of 4K videos (under two seconds), absence of visual artefacts, absence of freezing, and channel change time.
4K bearer networks require OTN downshifting to solve the problems of bandwidth and latency, using simplified O&M solutions to ensure 4K video experience. They also require a complete KPI system with which to evaluate the effects of bandwidth, latency, and packet loss on 4K. Planning, construction, and O&M for the bearer network can be carried out based on the results of this evaluation.
3 Huawei Intelligent OTN Soft Capabilities Ensure End-to-End 4K Service Experience
Huawei, drawing on many years of experience in transmission network planning and construction, project delivery, and network maintenance, launched an OTN soft capability system based on a simplified transmission platform.
This system covers design and planning for transmission networks, as well as delivery and operations for the entire lifecycle of the product. It takes advantage of the processing capability of the hardware, optimized software algorithms, high-precision monitoring methods, and improved multifaceted planning and design tools. It provides a complete intelligent OTN soft capability solution to telecommunications customers, solving the problems facing 4K services, such as bandwidth planning, service provisioning, and evaluation of 4K experience indicators.
3.1 Creating Design and Planning Tools and Processes Quickens Service Provisioning
As OTN equipment gradually downshifts to OLT and CO nodes, networks are increasing in scale. Improved quick design tools and scientific and efficient design processes are essential for planning OTN transmission networks.
The planning module for Huawei's intelligent OTN soft capability system includes planning tools, design tools, and verification tools. In the network planning stage, it applies end-to-end service design concepts. Using methods such as guided design, optoelectronic performance simulation, and visualized fault simulation, it ensures that OTN network architecture is scientifically designed, throughput is optimized, and protection is reliable. It also ensures that end-to-end 4K services are quickly and comprehensively provisioned.
On a typical network in China, a full-coverage comprehensive service region has over 300 OTN nodes. Using Huawei OTN planning software for network and service design reduces hardware configuration by 20%, increases wavelength timeslot utilization by 30%, and saves planning time by over 60%. The efficiency improvements for service provisioning are plain to see.
3.2 Automatic Delivery Ensures 4K Service Provisioning
Typically, transmission network delivery and commissioning are time consuming, but 4K services have clear requirements for provisioning time and quality. Ensuring service provisioning by providing fast, high-quality delivery is a fundamental challenge for OTN networks to overcome.
Huawei's intelligent OTN soft capability system uses a combination of OPM spectrum hardware scanning and check point data collection to carry out remote commissioning at the start of a project. Using the joint commissioning mechanism of optical parameters such as single-wavelength OSNR and the electrical parameters of service boards, it ensures end-to-end service performance. These tasks are all automatically completed using commissioning tools, lowering personnel and technical requirements for O&M and reducing the human resource and time costs of the project delivery phase by at least 25%. Typical deployment and delivery in the industry rely on manual operation and consume large amounts of time and resources, yet are unable to accurately find performance bottlenecks. Huawei's OTN soft capability optimization tools carry out end-to-end monitoring and optimization based on service dimensions. This allows for hardware resource optimization across the entire network, load balancing optimization, and discrete service clearing and optimization, ensuring that 4K services are quickly provisioned.
3.3 Visualization of Daily Operations is Vital for Ultimate 4K Experience
Typically, information on transmission networks is "invisible", which is inconvenient for O&M. Huawei's intelligent OTN soft capability system uses the visualization tool "Service and Network Dashboard". It comprehensively monitors the status of the electrical layer, the optical layer, and line optical fiber and makes this transmission network data visible to users. This brings convenience to daily tasks such as network maintenance, service management, and fault location. At the OTN system electrical layer, for the first time in the industry, Huawei has realized quick detection of SD bit errors at the chip level. This allows for quicker and more accurate location of points of failure. Using the delayed insertion of OTN alarms and configuration of the hold-off time ensures that routers do not suffer transient interruptions, preventing network instability. To ensure excellent 4K service experience, Huawei OTN uses end-to-end electrical-layer service latency detection. This allows for measurement and monitoring based on latency indicators for all services, ensuring optimization of end-to-end latency indicators. At the optical layer, Huawei OTN uses optical domain change detection at the millisecond level to locate transient points of failure, maintaining optical layer path status to avoid instability on the whole network. Monitoring of line optical fiber parameters is commonly the weak link in an OTN system.
Huawei OTN's Fiber Doctor module provides intelligent optical fiber monitoring, integrating the online OTDR function. This detects line optical fiber status, measures line attenuation in real time, and precisely locates fiber deterioration points and fiber cut points in lines. By monitoring the status of both the optical and electrical layers and comprehensively monitoring line optical fiber parameters, the Fiber Doctor comprehensively visualizes the OTN system status and line status.
Using Huawei OTN system dashboard interface, these functions allow users to visualize performance, reliability, and protection, as shown in the following figure:
The three modules on the network dashboard are:
Using resource analysis and management, the network dashboard intelligently monitors optical fibers on the entire network to provide detailed and accurate data to the carrier's O&M department. This data will be useful in guiding network upgrades and capacity expansion and transformation.
The service dashboard monitors single-wavelength OSNR, central spectrum, optical input/output power at check points, and other parameters, and performs dynamic monitoring and data presentation based on services. The bearer network applies the results of bandwidth assessment and user experience evaluation directly to the network and service dashboards. The industry's first 4K service is made perceivable and quantifiable, achieving the organic fusion of service experience and network O&M.
3.4 IP+Optical Synergy Allows for Accurate Location of 4K Service Faults
When carriers lease bandwidth or wavelengths, they typically do not maintain customers' routers in third-party data centers. Routers are then able to perceive OTN switching, which affects carrier KPI. During the cascading of protection schemes, if the hold-off time is not enabled on the router, OTN switching will trigger a transient interruption on the router. When a line fault occurs, inserting several IDLE streams (at a 50 ms step) will make the router unable to perceive link interruption. This avoids transient 4K stream interruptions, which would affect end user experience.
Services will automatically resume within a fixed latency range if link switching is completed or recovered. The router will not perceive single-digit millisecond link interruption or switching, and will not affect service networks or 4K experience. If the link connection is not recovered by the end of the fixed latency, OTN will insert a Local Fault alarm instead. When the router detects the Local Fault alarm, it will automatically resume services.
In the rapid development phase of 4K services and related products, Huawei has always been committed to improving overall network operation and maintenance capabilities. With powerful design planning tools, automatic optimization commissioning tools, service dashboard visualization, and quantitative 4K experience management systems, Huawei achieves a 4K-based end-to-end closed-loop O&M experience. Huawei has established a new industry standard with the service-oriented intelligent OTN soft capability system software.