Decoding the Super Engine OTN Behind the Three Major Operators' 100G Construction
July 17 morning news (by Qi Ming) At the end of last century, people once thought 2.5Gb/s was the limit of optical fiber transmission, former Nortel CEO John Roth's "Fiber Optic Revolution" brought humanity into the 10G era. Over a decade later, the former giant of optical communication has left the stage, but the 100G era has arrived as scheduled. Global large-scale deployment has started, and the giant ship of 100G will carry human communication for the next decade.
It is undeniable that the upgrading of optical signal rates has always accompanied the development of communication technology. The massive services brought by the ultra-broadband trend of communication networks are the biggest driving force behind the upgrading of optical networks. As a highway, the optical transport network should naturally upgrade from 10G/40G to 100G. However, the speed of 100G deployment has exceeded many industry insiders' expectations. What has enabled this giant ship to ride the wind and break the waves toward large-scale commercial use?
Market Turning Point: Chinese Operators Significantly Drive Maturity of the 100G Industry Chain
Ovum stated in its analysis report at the beginning of the year that with the volume increase of Chinese operators' 100G projects in 2013, the world will truly enter a new era of 100G. Objectively speaking, the rapid development of the 100G industry chain is inseparable from Chinese operators' needs for technological innovation and the demand driven by massive bandwidth growth.
The original backbone networks of the three major operators in China were basically based on 10G or 40G wavelengths. Compared with China Telecom and China Unicom, which had already built 40G trunk lines on a large scale, China Mobile faced the greatest bandwidth pressure among the three. In 2012, China Mobile first proposed large-scale construction of a 100G network in China, with the construction volume exceeding the total global 100G construction in 2011. This project became a turning point for global 100G commercial use, greatly stimulating further maturity of the 100G industry chain. Starting from April 2012 and lasting one year, various manufacturers exerted all their efforts and each provided complete 100G solutions, from 100G equipment to modules, components, and chips. Judging from rigorous test results and subsequent commercial situations, the 100G industry chain had matured. Subsequently, China Unicom conducted a tender for a 100G commercial trial network, and China Telecom also announced a larger-scale 100G procurement plan, marking the official arrival of the era of large-scale 100G construction.
Technology Engine: OTN Unleashes the Productivity of 100G
In the 100G solution, besides the line technology for high-speed 100G transmission, OTN cross-connection is extremely important for 100G networks. The two can be said to be the dual engines of 100G technology, the key technologies that enable the rapid development of 100G.
At the current stage, the service access rate of 100G networks is mainly 10G/10GE, with only the line rate using 100G. This requires mapping a large number of small-granularity 10G services into the large 100G pipe. Building networks using 100G WDM has obvious limitations. First, end sites cannot be freely accessed. Line and tributary are tightly coupled—whatever the line unit is, it limits the tributary services it can carry. All services must be strictly planned; new services require new wavelength design on the line side or procurement of new units. Second, intermediate nodes cannot be flexibly scheduled. From the first day of deployment, the source and destination are fixed. If changes are needed, manual patching of fiber connections at intermediate sites is required, or even adding hardware, which is time-consuming and laborious. Finally, the pipe cannot be efficiently utilized. The pipe and service are tightly coupled, and pipe resources cannot be shared by the platform. The large 100G pipe cannot be efficiently utilized, causing a huge waste of large-pipe resources. All services can only be transmitted point-to-point, and services across the entire network must have fixed directions. Spare line bandwidth cannot be shared or multiplexed by services on other paths.
With the rapid development of cloud computing, streaming media services, and mobile broadband, bandwidth acceleration, dynamic changes, and regional imbalances are intensifying. This traditional point-to-point approach cannot efficiently and flexibly adjust services to meet the needs of operators' networks. A 100G solution without OTN is like a highway without overpasses—vehicles can only get on and off at fixed intersections and cannot freely get on and off at different intersections or be dispatched among different highways.
The essence of OTN is the decoupling of pipes and services, and the decoupling of line and tributary. It is a huge technological transformation in the WDM industry and represents advanced productivity. If this productivity was not fully realized in the 10G/40G era, with the arrival of the 100G era, OTN functions will be fully demonstrated, irresistibly.
De-telecom-ization: Stunning OTN Achieves Network Cost Optimization
OTN brings the electronic digital technology that has seen tremendous development in recent years into the traditional WDM optical communication field, using the idea of optoelectronic integration to completely subvert the traditional point-to-point WDM architecture.
As is well known, Wei Leping proposed "de-telecom-ization" with an important principle of "optimizing network costs". Operators have shifted from focusing on the cost of individual network elements to optimizing the cost of the entire network.
OTN is an innovative case in the optical communication industry that reduces network construction, operation, and maintenance costs through technological innovation. Its typicality can be included in the textbook of telecom technology innovation. OTN achieves decoupling of pipes and services through standardized processing of service-side and line-side signals, greatly simplifying the service logic of WDM networks. OTN realizes flexible configuration of line capacity, flexible access and scheduling of multiple services, and provides complete protection, thereby enabling fine-grained operation of large 100G pipes and making the 100G network controllable, manageable, and operable. In today's era of sharply increasing network maintenance costs, its value stands out. It simplifies the deployment of network services and greatly reduces operational costs.
Compared with traditional WDM, OTN equipment only needs to add cross-connect boards and backplane buses. Compared with the system's 100G line cards and optical layer components, the added cost of the system is less than 2%, but the bandwidth utilization rate, service provisioning efficiency, and operation and maintenance efficiency are improved by more than 30%, greatly reducing the network's operation and maintenance costs. "Network cost optimization" is achieved, which conforms to the trend of "de-telecom-ization".
After several years of development and the rapid arrival of 100G, OTN technology has been widely accepted by the industry. In 2013, the authoritative industry analysis firms Ovum and Infonetics both clearly pointed out in their analysis reports that in the 100G era, OTN technology and 100G technology are strongly coupled. Infonetics' latest OTN technology survey report in May 2013 showed that 44% of customers globally had already used OTN technology to build WDM networks in 2013, and this proportion is expected to rise to 89% by 2016. It also emphasized that with the development of high-speed line technologies such as 100G and beyond 100G, the combination of OTN and WDM is an inevitable technological trend.
Driven by the Three Major Domestic Operators: 100G Will Inevitably Strengthen OTN Technology Application
Not only China Mobile, but China Telecom and China Unicom have all raised the banner of OTN in their respective projects, pointing out the main channel for the development of optical networks.
In fact, as early as the 40G era, China Telecom and China Unicom had introduced OTN technology into 90% of new provincial backbone and metropolitan area network projects. Because of its flexible service scheduling and rapid service provisioning, OTN technology has long been recognized by the provincial branches of the three major operators.
In 2012, China Unicom built an OTN 40G national backbone private network to uniformly schedule and manage the existing 10G/2.5G private line services, greatly optimizing the deployment and adjustment of private line services and improving the response speed to large customers.
In 2013, China Telecom also began to change its traditional national backbone network construction model and introduced an equipment-integrated OTN scheduling plane based on 100G WDM, specifically for consolidating and scheduling small-granularity services and private line services within the 100G pipe.
In summary, although the three major domestic operators may differ in the ways they apply OTN, there is no controversy about the necessity of applying OTN technology.
Just as the technological revolution led by Nortel quickly enabled 10G technology to win the market, the long-term bandwidth hunger of backbone networks will accelerate the commercialization of 100G. The enormous value that the super engine OTN brings to the network is the driving force, which will surely propel the giant ship of 100G to ride the wind and break the waves, fully demonstrating the technological charm of optoelectronic integration.