Synchronous optical networking (SONET) and synchronous digital hierarchy (SDH) are standardized protocols that transfer multiple digital bit streams synchronously over optical fiber using lasers or highly coherent light from light-emitting diodes (LEDs). At low transmission rates data can also be transferred via an electrical interface. The method was developed to replace the plesiochronous digital hierarchy (PDH) system for transporting large amounts of telephone calls and data traffic over the same fiber without the problems of synchronization.
Network topology is the arrangement of the elements of a communication network. Network topology can be used to define or describe the arrangement of various types of telecommunication networks, including command and control radio networks, industrial fieldbusses and computer networks.
An optical switch is a device that selectively switches optical signals from one channel to another. The switching can be temporal or spatial.The former is known as an optical (time-domain) switch or an optical modulator, while the latter is called an optical space switch or an optical router. In general, optical modulators and routers can be made from each other.
Hybrid fiber-coaxial (HFC) is a telecommunications industry term for a broadband network that combines optical fiber and coaxial cable. It has been commonly employed globally by cable television operators since the early 1990s.
The Radio Network Controller (RNC) is a governing element in the UMTS radio access network (UTRAN) and is responsible for controlling the Node Bs that are connected to it. The RNC carries out radio resource management, some of the mobility management functions and is the point where encryption is done before user data is sent to and from the mobile. The RNC connects to the Circuit Switched Core Network through Media Gateway (MGW) and to the SGSN in the Packet Switched Core Network.
In a hierarchical telecommunications network, the backhaul portion of the network comprises the intermediate links between the core network, or backbone network, and the small subnetworks at the edge of the network.
A digital cross-connect system is a piece of circuit-switched network equipment, used in telecommunications networks, that allows lower-level TDM bit streams, such as DS0 bit streams, to be rearranged and interconnected among higher-level TDM signals, such as DS1 bit streams. DCS units are available that operate on both older T-carrier/E-carrier bit streams, as well as newer SONET/SDH bit streams.
MPLS Fast Reroute is a local restoration network resiliency mechanism. It is actually a feature of resource reservation protocol (RSVP) traffic engineering (RSVP-TE). In MPLS local protection each label switched path (LSP) passing through a facility is protected by a backup path which originates at the node immediately upstream to that facility.
In a telecommunication network, a ring network affords fault tolerance to the network because there are two paths between any two nodes on the network. Ring protection is the system used to assure communication continues in the event of failure of one of the paths. There are two widely used protection architectures: 1+1 protection and 1:1 protection.
In telecommunications, subnetwork connection protection (SNCP), is a type of protection mechanism associated with synchronous optical networks such as synchronous digital hierarchy (SDH).
In telecommunications, radio frequency over glass (RFoG) is a deep-fiber network design in which the coax portion of the hybrid fiber coax (HFC) network is replaced by a single-fiber passive optical network (PON). Downstream and return-path transmission use different wavelengths to share the same fiber. The return-path wavelength standard is expected to be 1610 nm, but early deployments have used 1590 nm. Using 1590/1610 nm for the return path allows the fiber infrastructure to support both RFoG and a standards-based PON simultaneously, operating with 1490 nm downstream and 1310 nm return-path wavelengths.
An optical mesh network is a type of optical telecommunications network employing wired fiber-optic communication or wireless free-space optical communication in a mesh network architecture.
A remote radio head (RRH), also called a remote radio unit (RRU) in wireless networks, is a remote radio transceiver that connects to an operator radio control panel via electrical or wireless interface. When used to describe aircraft radio cockpit radio systems, the control panel is often called the radio head.
E-UTRAN Node B, also known as Evolved Node B, is the element in E-UTRA of LTE that is the evolution of the element Node B in UTRA of UMTS. It is the hardware that is connected to the mobile phone network that communicates directly wirelessly with mobile handsets (UEs), like a base transceiver station (BTS) in GSM networks.
Shared risk resource group is a concept in optical mesh network routing that different networks may suffer from a common failure if they share a common risk or a common SRG. SRG is not limited to Optical mesh networks: SRGs are also used in MPLS, IP networks, and synchronous optical networks.
A multicast session requires a "point-to-multipoint" connection from a source node to multiple destination nodes. The source node is known as the root. The destination nodes are known as leaves. In the modern era, it is important to protect multicast connections in an optical mesh network. Recently, multicast applications have gained popularity as they are important to protecting critical sessions against failures such as fiber cuts, hardware faults, and natural disasters.
Link protection is designed to safeguard networks from failure. Failures in high-speed networks have always been a concern of utmos importance. A single fiber cut can lead to heavy losses of traffic and protection-switching techniques have been used as the key source to ensure survivability in networks. Survivability can be addressed in many layers in a network and protection can be performed at the physical layer, Layer 2 and Layer 3 (IP).
Path protection in telecommunications is an end-to-end protection scheme used in connection oriented circuits in different network architectures to protect against inevitable failures on service providers’ network that might affect the services offered to end customers. Any failure occurred at any point along the path of a circuit will cause the end nodes to move/pick the traffic to/from a new route. Finding paths with protection, especially in elastic optical networks, was considered a difficult problem, but an efficient and optimal algorithm was proposed.
Segment protection is a type of backup technique that can be used in most networks. It can be implemented as a dedicated backup or as a shared backup protection. Overlapping segments and non-overlapping segments are allowed; each providing different advantages.
The p-Cycle protection scheme is a technique to protect a mesh network from a failure of a link, with the benefits of ring like recovery speed and mesh-like capacity efficiency, similar to that of a shared backup path protection (SBPP). p-Cycle protection was invented in late 1990s, with research and development done mostly by Wayne D. Grover, and D. Stamatelakis.
