What is the difference between DWDM and OTN?

1. Conceptual differences between DWDM and OTN

?

Dense Wavelength Division Multiplexing (DWDM: Dense Wavelength Division Multiplexing) is a method that combines multiple light waves into a set of optical wavelengths and uses one optical fiber to transmit them within the range of the gain that EDFA can provide near the wavelength window of 1550nm. Laser technology to increase bandwidth on fiber optic backbones. Rather, the technology multiplexes closely spectrally spaced individual fiber carriers within a given fiber in order to exploit achievable transmission performance (e.g., to achieve minimal dispersion or attenuation). In this way, the total number of optical fibers required can be reduced for a given information transmission capacity.

?

OTN (Optical Transport Network) is a transport network that organizes networks at the optical layer based on wavelength division multiplexing technology. It is the next generation backbone transport network. The OTN switching module is added to this technology, so that the system can flexibly schedule communication services, expand, promote, and increase client information, and improve the business capabilities of network communication, thereby solving the problem of traditional WDM networks without wavelengths/sub-wavelengths. Problems such as poor business scheduling capabilities, weak networking capabilities, and weak protection capabilities.

?

??2. Different signal formats

?

DWDM technology does not have a corresponding frame structure. During operation, the wavelength of a single signal is converted into the corresponding wavelength in network communication through a converter, and the transmission wavelength is multiplexed through optical technology.

?

OTN has a complete frame structure. It can schedule wavelengths through electrical crossover technology to achieve an electrical crossover function similar to SDH, so that small-particle signals can be merged and transmitted in a large channel. One channel of OTN can also have large signals like SDH. For large and small containers, OTN has the ability to access and process from the institutional perspective, improving bandwidth utilization efficiency. OTN technology can also monitor the working performance, faults and other issues of the network communication power regeneration part. In the process of performance fault detection, OTN technology is more superior.

?

??3. Differences in networking and protection mechanisms

?

DWDM technology networking modes are mainly point-to-point, chain, star, and ring networking. In terms of protection mode, only grassroots protection is provided. The protection mode is mainly optical multiplex section protection. 1+1 and 1 are used on the optical path. :1 protection. Terminal equipment is not protected. This protection method requires two independently routed optical cables. DWDM's self-healing protection of services is performed in the SDH ring network.

?

OTN networking is usually ring networking, mesh and other networking methods, which can provide line 1+1 protection, wavelength 1+1 protection, client side 1+1 protection, ODUk protection, optical layer and electrical layer protection, etc.

?

??4. Business dispatching capabilities

?

?In OTN, data configuration can be used for cross-connection (similar to SDH business configuration), multiple types of services can be accessed at the same time, and intelligent scheduling of services can be achieved. It can provide mixed scheduling capabilities for optical layer wavelength level and electrical layer sub-wavelength level services. Optical layer scheduling capability: The optical layer provides OADM wavelength scheduling method, which can pre-plan the input/output of fixed wavelengths, and can also use AWG output.

?

?All wavelengths are input/outputted. The wavelengths that require upstream and downstream services are connected to the service board. The wavelengths that do not require upstream and downstream services are scheduled using pigtail jumpers. Electrical layer scheduling capability: Provides distributed electrical cross-connection of ODU0/ODU1/ODU2/ODU2e/ODU3/ODU4 particles, with the cross-connect capacity of adjacent slots reaching 100/200Gbps.

?

??5. Application scenarios

?

DWDM is mainly used in inter-provincial trunk networks and intra-provincial backbone networks. It mainly uses point-to-point networking methods to achieve line protection. If the line protection method is used, more lines need to be laid, which is costly. Therefore, DWDM's self-healing protection of services is combined with the SDH ring network and is widely used.

?

OTN network provides a very ideal solution for large broadband granular services. OTN network deployment is carried out in the inter-provincial backbone network, intra-provincial backbone network, and metropolitan core layer of telecom operators, and provides scheduling of service granules above Gb/s. The inter-provincial backbone network carries long-distance services such as PSTN/2G/3G/4G/internet. The use of OTN networks can implement various forms of protection methods and has strong protection capabilities. The provincial backbone network carries services such as NGW/3G/4G/IPTV large customer dedicated lines between backbone routers. The metro core network carries large-grain services between local network core routers and aggregation routers. Through the construction of provincial backbone network OTN and metropolitan area network core layer OTN network.