- Industry: Consulting
- Number of terms: 1807
- Number of blossaries: 2
- Company Profile:
Gartner delivers technology research to global technology business leaders to make informed decisions on key initiatives.
SDH/SONET technology differs by region. SONET is sold only in North America. SDH is sold outside North America and comes in two types: SDH (Japan) is sold only in Japan, while SDH (ETSI) is sold in the rest of the world. SDH/SONET supports ring and mesh topologies, and protection of circuits through automatic protection switching (APS) is standard, via various protection programs.
SDH/SONET comes in standardized bit rates, with SDH circuits referred to as synchronous transfer mode (STM)-x (where x = 1, 4, 16, 64 and 256) connections and SONET circuits known as Optical Carrier Rate (OC)-n (where n = 3, 12, 48, 192, 768) connections. The standardized bit rates are:
STM-1/OC-3 (155 Mbps).
STM-4/OC-12 (622 Mbps).
STM-16/OC-48 (2.5 Gbps).
STM-64/OC-192 (10 Gbps).
STM-256/OC-768 (40 Gbps).
Originally, the SDH/SONET standards were defined as a rigid hierarchy optimized specifically to handle circuit-based voice traffic. With the requirement to support data services becoming more evident, additions were made to the SDH/SONET standards to allow for more flexible traffic handling, especially with regard to data services in general and Ethernet services in particular. New features such as the Generic Framing Procedure (GFP) and LCAS were added to the standards, as well as support for increased control plane functionality as defined in the standards for Automatic Switched Transport Network (ASTN)/Automatic Switched Optical Network (ASON).
In addition, vendors have added cross-connect functionality to SDH/SONET equipment to support add/drop functionality. Also, convergence between SDH/SONET and WDM products has become the norm in the optical transport market.
Industry:Technology
Scriptless testing tools reduce or eliminate the amount of scripting involved in the creation of tests using model-, object-, data- or keyword-driven approaches. The goal is to enable business user testing and to reduce maintenance costs. The majority of products are focused on functional automation, but performance testing products are also appearing.
Industry:Technology
Prevention of electric, magnetic, or electromagnetic fields from escaping or entering an enclosed area by means of a barrier. Also called shielding.
Industry:Technology
Similar to application sharing, but not all parties can update the document simultaneously.
Industry:Technology
Populating a call center agent’s screen with just-in-time customer information.
Industry:Technology
A coding device applied to a digital channel that produces an apparently random bit sequence. A corresponding device is used to decode the channel, i.e., the coding is reversible.
Industry:Technology
Scope, track, rank, evaluate, evangelize and transfer (STREET) represents best practices in the technology planning and adoption process. STREET is suitable for an emerging technology group to use or adapt in defining its own internal process, or for business leaders, innovators or other individuals involved in innovation adoption to use as a checklist of key activities.
Industry:Technology
A cause of light wave signal loss in optical fiber transmission. Diffusion of a light beam caused by microscopic variations in the material density of the transmission medium.
Industry:Technology
A device that resolves a two-dimensional object, such as a business document, into a stream of bits by raster scanning and quantization.
Industry:Technology
The measure of a system’s ability to increase or decrease in performance and cost in response to changes in application and system processing demands. Examples would include how well a hardware system performs when the number of users is increased, how well a database withstands growing numbers of queries, or how well an operating system performs on different classes of hardware. Enterprises that are growing rapidly should pay special attention to scalability when evaluating hardware and software.
Industry:Technology
