O	o
OA	Ordered Aggregate
OA&M	Operations, Administration &Management
OAEP	Optimal Asymmetric Encryption Padding
OAIS	Open Archival Information System
OAM	Operations And Maintenance
OC	Open Confirm
OC	Operational Code
OC	Operator Clear
OCDNL	Original Chinese Domain Name Label
OCF	Open Connectivity Foundation
OCI	Object Content Info
OCI	Open Connection Indication
OCN	Open Computer Network
OCP	Objective Code Point
OCR	Optical Character Recognition
OCRA	OATH Challenge-Response Algorithm
OCS	Overload Control State
OCSP	Online Certificate Status Protocol
ODA	Office Document Architecture
ODAD	Optimistic Duplicate Address Detection
ODM	original design manufacturer
ODMR	ON-DEMAND MAIL RELAY
ODN	Optical Distribution Network
ODVA	Open DeviceNet Vendors Association
OEM	original equipment manufacturer
OEO	optical-electronic-optical
OF	Objective Function
OF0	Objective Function 0
OFDM	Orthogonal Frequency Division Multiplexing
OFDMA	Orthogonal Frequency Division Multiple Access
OFED	Open Fabrics Enterprise Distribution
OGA	ORCHID Generation Algorithm
OGC	Open Geospatial Consortium
OGF	Open Grid Forum
OH	Outer Header:
OHB	Original Header Block
OHC	Outbound Hop Count
OI	Optical Interface
OI	Override Interval
OIF	Optical Interworking Forum
OIW	OSI Implementor's Workshop
OLI	Originating Line Information
OLS	On-Line System
OLS	optical line system
OLSR	Optimized Link State Routing
OLT	Optical Line Terminal
OM	Object Management
OM	Overlay Multicast
OMA	Open Mobile Alliance's
OMG	originating media gateway
OMGC	originating media gateway controller
OMNA	Open Mobile Naming Authority
OMS	optical multiplex section
ON	Optimistic Node
ONA	OGC Naming Authority
ONC	Open Network Computing
ONE	Opportunistic Network Environment
ONF	Open Networking Foundation
ONL	Open Network Lab
ONT	Optical Network Termination
ONU	Optical Network Unit
OOB	out-of-band
OOF	Out of Frame
OOS	Out of Service
OOS	Out-of-Sequence
OP	OpenID Provider
OP	Operational Plane
OP	Originating Proxy
OPES	Open Pluggable Edge Services
OPS	Optical Physical Section
OPWA	One Pass With Advertising
OR	Onward Routing
OR	Overlapping Relay
ORA	organizational registration authority
ORAR	Originator Requested Alternate Recipient
ORAU	Oak Ridge Associated Universities
ORF	Outbound Route Filtering
ORNL	Oak Ridge National Laboratory
ORO	Option Request Option
ORO	Options Request Option
OS	Operations System
OS	Opportunistic Security
OS	operating system
OSC	Optical Supervisory Channel
OSI	Open System Interconnection
OSI	Open Systems Interconnection
OSIE	Open Systems Interconnection Environment
OSNR	Optical Signal Noise Ratio
OSP	Open Settlements Protocol
OSPF	Open Shortest Path First
OSPF	Open Shortest-Path First
OSPF	Open Shotrest Path First
OSPS	Operator Services Position System
OSS	Operational Support System
OSS	Operations Support Systems
OT	Operation Technology
OT	Operational Technology
OT	Override Timer
OTAPA	Over-the-Air Parameter Administration
OTAR	over-the-air rekeying
OTASP	Over-the-Air Service Provisioning
OTF	Origin Timestamp Format
OTN	Optical Transport Network
OTP	One Time Password
OTP	One-Time Password
OTPS	One-Time Password Specifications
OTS	Optical Transport System
OTS	optical transmission section
OTT	Over The Top
OTT	Over-the-Top
OU1	Organizational Unit 1
OU2	Organizational Unit 2
OU3	Organizational Unit 3
OU4	Organizational Unit 4
OUI	Organisationally Unique Identifier
OUI	Organizational Unique Identifier
OUI	Organizationally Unique Identifier
OWAMP	One-Way Active Measurement Protocol
OWASP	Open Web Application Security Project
OWD	One-Way Delay
OWS	Optional white space