O
Open Network Foundation (ONF)
A non-profit organization responsible for the development and standardization of a software architecture that supports
Software-Defined Networking (SDN). ONF is also responsible for the commercialization and promotion of SDN as a concept and its underlying technologies. For more, see:
https://www.opennetworking.org/.
Open Shortest Path First (OSPF)
An
Interior Gateway Protocol (IGP) based on
link-state routing. OSPF is widely deployed in large networks because of its efficient use of network bandwidth and its rapid convergence after changes in
topology. Defined in RFCs 2328 and RFC 5340.
OSPF advertises the states of local network links within an
autonomous system (AS) and makes routing decisions based on the
shortest path first (SPF) algorithm. Each OSPF router maintains an identical database describing the autonomous system's topology. From this database, a
Routing Information Base (RIB) is calculated by constructing a
shortest path tree (SPT).
OSPF features include least-cost routing, multipath routing, and load balancing. OSPF includes explicit support for
Classless Interdomain Routing (CIDR) and the tagging of externally derived routing information.
OSPF version 2 supports IPv4 and OSPF version 3 supports IPv6.
OSPF divides an autonomous system into contiguous groups of networks called
areas.
• In a standard area, intra-area routes, inter-area routes, and external routes (learned from other routing protocols such as RIP and BGP) are distributed. Inter-area routes and external routes are distributed as summary addresses.
• A backbone area is essentially a standard area which has been designated as the central point to which all other areas connect. A backbone area combines a set of independent areas into an AS and acts as a hub for inter-area transit traffic and routing information distribution. Each non-backbone area is directly connected to the backbone area.
Open Systems Interconnection (OSI) Reference Model
A conceptual model defined by the
International Organization for Standardization (ISO) that organizes the computer-to-computer communications process into seven layers. Each layer provides services to the layer above and receives services from the layer below. Such a set of layers is called a
protocol stack.
Layers seven through five manage end-to-end communications between the message source and destination, while layers one through four manage network access:
• Layer 4 (L4) ensures the end-to-end delivery from a source to a destination
• Layer 3 (L3) routes packets of data from source to destination across a network
• Layer 2 (L2) reliably transports data across the physical link between two directly connected nodes
• Layer 1 (L1) conveys the bit stream at the electrical and mechanical level
The OSI Reference Model is often compared to the more descriptive (versus prescriptive)
Transmission Control Protocol/Internet Protocol (TCP/IP) model.
Open vSwitch (OVS)
A software switch used in virtualized server environments that forwards traffic between different
virtual machine (VM) instances on the same physical host and between VMs and the physical network. OVS enables network automation through programmatic extension, while still supporting standard management interfaces and protocols. For more, see
http://openvswitch.org/.
OpenStack
A cloud operating system that controls pools of compute, storage, and networking resources in a data center which users manage through a Web-based dashboard, command-line tools, or a RESTful API. See also
Neutron.
Operation, Administration, and Maintenance (OAM)
A set of
Ethernet specifications that provide connectivity monitoring, fault detection and notification, fault verification, fault isolation,
loopback, and remote defect identification. The primary specifications are
802.3ah link-fault management (LFM) and
802.1ag Connectivity Fault Management (CFM).
Last modified date: 06/16/2023