PDF of this tutorialNetwork-management functions, which are an important part of operating a network, are available today using an optical switch having an electronic-based switching matrix. Available today with proven technology, these intelligent O-E-O switches address the need for high-bandwidth management while continuing the tradition of providing easy fault location and the performance-monitoring information necessary to monitor and report on the health of a network. The intelligent O-E-O switch using an electronic fabric is also able to offer bandwidth grooming, which is not available in an all-optical switch. Although an O-O-O switch will support a new class of wavelength-based services, the intelligent O-E-O switch will support a new class of high-bandwidth services. This is an incremental step in the operations and maintenance of a new service class that is not disruptive to a carriers' normal mode of operations. It addresses the need to manage a larger aggregate of bandwidth by processing and grooming the information at a 2.5 Gbps rate. By using an electronic-based fabric, the intelligent O-E-O switch is able to overcome the network impairments that currently limit the use of an all-optical switch in a dynamic mesh architecture. An intelligent O-E-O switch combines the latest generation hardware with sophisticated software to better accommodate the data-centric requirements of a dynamic optical network. The intrinsic 3R regeneration functions allow the intelligent optical switch to be deployed in various network architectures including mesh. An intelligent O-E-O switch provides carriers with a marketable service differentator against their competition by offering carrier-grade protection and fast provisioning of services.
Figure 6. O-E-O Switch
The intelligent O-E-O switch encourages the use of mesh, which is more bandwidth efficient and supports a flexible set of bandwidth-intensive service offerings. The electronics used in an intelligent optical switch also allows it to make use of the well-accepted synchronous optical network (SONET) standards. This not only helps with network management, but it also encourages the use of best-of breed network elements by furthering interoperability among devices from multiple vendors. Not only does the intelligent O-E-O switch offer advantages from the reuse of SONET standards, but it also includes an evolution path to maximize the use of a set of data standards to improve data-centric communications and make the network more dynamic while greatly reducing provisioning times. The evolution of the intelligent optical switch includes the support of evolving standards such as optical-user interface network (O–UNI)/generalized multiprotocol label switching (GMPLS). GMPLS is an emerging standard, which is based on the established, data-oriented, multiprotocol label switching (MPLS) standard. MPLS is a standard suite of commercially available data protocols that handles routing in a data network.
Figure 7. O–UNI Using Intelligent Optical Switches
GMPLS is intended to make the benefits of data routing available to large carrier-class optical switches supporting dynamic global networks. Intelligent optical switches are currently being deployed in networks. They are helping to evolve the network while also providing carriers with both cost-reduction and new revenue-generating services. The intelligent optical switches, using an electronic-based switching fabric, mitigate the risks that are associated with the deployment of new all-optical technology. O-E-O switches are available today and can be deployed without the technical challenges of all-optical switches. As these switches continue to scale, support new data-centric features, and drop in price, they diminish the need for all-optical switching.
OxO
The intelligent O-E-O switch currently provides an evolution path for the next-generation network without the network risks imposed by all-optical O-O-O switches. This is not to say that the all-optical switch will not or should not be deployed in the next-generation network. On the contrary, the all-optical switch should be added to the network at the right time to continue the evolution to a less costly, more manageable dynamic network. However, instead of viewing the all-optical switching technology as competition to an electronic-based optical switch, we must embrace the idea that the two are complementary, allowing a best of both: OxO. Carriers can use a combination of the two switches to offer new bandwidth and end-to-end wavelength services. The O-E-O switch will help mitigate the network impairments, which would otherwise accumulate with all optical switches. And, the all-optical switch will help to further the trend of reducing the footprint and power requirements in an office while providing bit-rate and protocol transparency for new revenue service offerings.
Figure 8. Best of OxO
