TermO

OA&M	Operations, Administration and Maintenance	Implementation of a modern, integrated and computerised OA&M system is seen as a prerequisite for provision of AIN-type services.
OADM	Optical Add Drop Multiplexer
OAM	Operation, Administration and Maintenance	An industry term for system management operations.
OBC	Out-of-Band Connection	A remote link, or a link outside connected networks, established over a modem. It is useful when network communications are not available.
OBM	Optimized Bandwidth Management	Cisco wide-area switches ensure fair and cost-efficient bandwidth utilization using various techniques. ABR and Optimized Bandwidth Management are used for ATM and Frame Relay traffic. ABR is a standards-based ATM traffic management mechanism, and ForeSight is Cisco's implementation that mirrors ABR capabilities for Frame Relay traffic. ABR and Optimized Bandwidth Management optimize real-time traffic performance and throughput, and minimize data loss. Bandwidth management for voice is achieved through the use of standards-based voice compression and silence suppression mechanisms for circuit data services.
OC	Optical Carrier	A hierarchy of optical signals used to classify speeds, or capacities, of fibre lines, especially as related to the SONET standard. The basic speed is OC-1 (52Mbps). An OC-48 fibre line has a capacity of 2.5 gigabits a second and an OC-192 line 10 gigabits a second.
OC3c SONET		A SONET-based fibre-optic User-to-Network Interface (UNI), either public or private, operating at 155.52 Mbps over single-mode and multimode optical fibre.
OC-n	Optical Carrier-bit rate	Bit rate of North America Sonet hierarchy
Octet		Eight data bits
ODA	Open Document Architecture	ISO standard that specifies how documents are represented and transmitted electronically. Formerly called Office Document Architecture.
ODBC	Open DataBase Connectivity	Standard application programming interface for accessing data in both relational and non-relational database management systems. Using this application programming interface, database applications can access data stored in database management systems on a variety of computers even if each database management system uses a different data storage format and programming interface. ODBC is based on the call level interface specification of the X/Open SQL Access Group and was developed by Digital Equipment Corporation, Lotus, Microsoft, and Sybase.
ODI	Open Data-Link Interface	Novell specification providing a standardized interface for NICs (network interface cards) that allows multiple protocols to use a single NIC.
ODSI	Open Directory Services Interface
OEM	Original Equipment Manufacturer
OFDM	Orthogonal Frequency-Division Multiplexing.	A Frequency-Division Multiplexing (FDM) scheme utilized as a digital multi-carrier modulation method.
OFDMA	Orthogonal Frequency-Division Multiple Access	A multi-user version of the popular Orthogonal Frequency-Division Multiplexing (OFDM) digital modulation scheme. Multiple access is achieved in OFDMA by assigning subsets of subcarriers to individual users, allowing simultaneous low data rate transmission from several users.
OIM	OSI Internet Management	Group tasked with specifying ways in which OSI network management protocols can be used to manage TCP/IP networks.
OLE	Object Link Embedding technology	Object Linking and Embedding. A Microsoft technology which allows you to link elements from different applications within each other. For example, you can embed an Excel spreadsheet or chart inside a PowerPoint presentation. When you change the chart or spreadsheet, it changes inside the PowerPoint presentation.
OLO	Other Licenced Operator
OMG	Object Management Group
ONA	Open Network Architecture	An FCC-mandated plan for AT&T and the Bell companies, by which the companies must give network interconnection of the same quality
ONP	Open Network Provision	The European Commission's proposed set of technical interfaces, usage conditions and tariff principles for opening public networks to competition. Comparable to Open Network Architecture in the United States.
ONPCCP	ONP Consultative and Co-ordination Platform
Open System		Any system based on publicly available standards for subsystem interaction that facilitates multi-vendor and multi-technology integration. Open systems are portable, scaleable, and interoperable.
OPXC	Optical Path Cross Connect
OSI	Open Systems Interconnection	A model for computer networking based on the seven-layer OSI reference model, defined by the International Organisation for Standardisation, which lets computers from different manufacturer communicate using local or wide area networks.
OSI Network Address		Address, consisting of up to 20 octets, used to locate an OSI Transport entity. The address is formatted into two parts: an Initial Domain Part that is standardized for each of several addressing domains and a Domain Specific Part that is the responsibility of the addressing authority for that domain.
OSPF	Open Shortest Path First	A routing protocol.
OSS	Operations Support System	Network management system supporting a specific management function, such as alarm surveillance and provisioning, in a carrier network. Many OSSs are large centralized systems running on mainframes or minicomputers.
OUI	Organizational Unique Identifier	3 octets assigned by the IEEE in a block of 48-bit LAN addresses.
Out-of-Band Signalling		Transmission using frequencies or channels outside the frequencies or channels normally used for information transfer. Out-of-band signalling is often used for error reporting in situations in which in-band signalling can be affected by whatever problems the network might be experiencing.
Overflow		The process of dialling additional bandwidth to accommodate peak traffic loads, and reducing the total bandwidth during times of reduced traffic loads.