Related Research Articles
The Open Systems Interconnection model is a conceptual model that characterises and standardises the communication functions of a telecommunication or computing system without regard to its underlying internal structure and technology. Its goal is the interoperability of diverse communication systems with standard communication protocols.
The plesiochronous digital hierarchy (PDH) is a technology used in telecommunications networks to transport large quantities of data over digital transport equipment such as fibre optic and microwave radio systems. The term plesiochronous is derived from Greek plēsios, meaning near, and chronos, time, and refers to the fact that PDH networks run in a state where different parts of the network are nearly, but not quite perfectly, synchronized.
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.
In the seven-layer OSI model of computer networking, the physical layer or layer 1 is the first and lowest layer. This layer may be implemented by a PHY chip.
Connectionless-mode Network Service (CLNS) or simply Connectionless Network Service is an OSI Network Layer datagram service that does not require a circuit to be established before data is transmitted, and routes messages to their destinations independently of any other messages. As such it is a "best-effort" rather than a "reliable" delivery service. CLNS is not an Internet service, but provides capabilities in an OSI network environment similar to those provided by the Internet Protocol (IP). The service is specified in ISO 8348, the OSI Network Service Definition
The STM-1 is the SDH ITU-T fiber optic network transmission standard. It has a bit rate of 155.52 Mbit/s. Higher levels go up by a factor of 4 at a time: the other currently supported levels are STM-4, STM-16, STM-64 and STM-256. Above STM-256 wavelength-division multiplexing (WDM) is commonly used in submarine cabling.
Specification and Description Language (SDL) is a specification language targeted at the unambiguous specification and description of the behaviour of reactive and distributed systems.
H.320 or Narrow-band visual telephone systems and terminal equipment is an umbrella Recommendation by the ITU-T for running Multimedia (Audio/Video/Data) over ISDN based networks. The main protocols in this suite are H.221, H.230, H.242, audio codecs such as G.711 (PCM) and G.728 (CELP), and discrete cosine transform (DCT) video codecs such as H.261 and H.263.
Many services running on modern digital telecommunications networks require accurate synchronization for correct operation. For example, if telephone exchanges are not synchronized, then slips will occur and degrade performance. Telecommunication networks rely on the use of highly accurate primary reference clocks which are distributed network-wide using synchronization links and synchronization supply units.
Virtual concatenation (VCAT) is an inverse multiplexing technique creating a large capacity payload container distributed over multiple smaller capacity TDM signals. These signals may be transported or routed independently. Virtual concatenation has been defined for SONET/SDH, OTN and PDH path signals.
Reference Model of Open Distributed Processing (RM-ODP) is a reference model in computer science, which provides a co-ordinating framework for the standardization of open distributed processing (ODP). It supports distribution, interworking, platform and technology independence, and portability, together with an enterprise architecture framework for the specification of ODP systems.
ITU-T defines an Optical Transport Network (OTN) as a set of Optical Network Elements (ONE) connected by optical fiber links, able to provide functionality of transport, multiplexing, switching, management, supervision and survivability of optical channels carrying client signals. An ONE may Re-time, Re-Amplify, Re-shape (3R) but it does not have to be 3R – it can be purely photonic. Unless connected by optical fibre links, it shall not be OTN. Mere functionality of switching, management, supervision shall not make it OTN, unless the signals are carried through optical fibre.
The Full Service-VDSL Committee (FS-VDSL) was founded in July 2000 with the aim of rapidly specifying a low cost, high capability end-to-end multi-service network based on VDSL Frequency Band Plan 998 which can be quickly and economically deployed to enable customers, focusing principally on consumer market, to benefit from competition. It was a non-profit international organization based in Switzerland. FS-VDSL was closed, according to its statutes, after 3 years of activity. Its specifications, downstreamed to ITU-T Study Group 16 became international standards as Recommendations H.610 and H.611.
Ethernet over PDH or EoPDH is one of many techniques that provided Ethernet connectivity over non-Ethernet networks. Specifically, EoPDH is a standardized methodology for transporting native Ethernet frames over the existing telecommunications copper infrastructure by leveraging the established PDH transport technology. EoPDH is one of several Ethernet transport technologies that enables Telecommunication Service Providers to offer "Carrier Ethernet" services. Also commonly used as a means of connecting businesses to a Metro Ethernet network.
ITU-T Recommendation G.806"Characteristics of transport equipment - Description methodology and generic functionality" specifies a methodology to describe equipment for transport networks based on the transport processing functions and architectural entities defined in ITU-T Recommendation G.805.
T-MPLS or Transport MPLS is a transport network layer technology that uses extensions to a subset of the existing MPLS standards and is designed specifically for application in transport networks. Work to define T-MPLS was started by the ITU-T in February 2006. It was intended specifically as a connection-oriented packet-switched (co-ps) application offering a simpler implementation by removing MPLS features that are not relevant to co-ps applications and adding mechanisms that provide support of critical transport functionality.
Ethernet over PDH over SONET/SDH (EoPoS) is one of many techniques that provided Ethernet connectivity over non-Ethernet networks. EoPoS is a standardized method for transporting native Ethernet frames over the existing telecommunications optical infrastructure use both the established Plesiochronous Digital Hierarchy (PDH) and Synchronous Digital Hierarchy (SONET/SDH) transport technologies.
Multiprotocol Label Switching - Transport Profile (MPLS-TP) is a variant of the MPLS protocol that is used in packet switched data networks. MPLS-TP is the product of a joint Internet Engineering Task Force (IETF) / International Telecommunication Union Telecommunication Standardization Sector (ITU-T) effort to include an MPLS Transport Profile within the IETF MPLS and PWE3 architectures to support the capabilities and functionalities of a packet transport network.
Synchronous Ethernet, also referred as SyncE, is an ITU-T standard for computer networking that facilitates the transference of clock signals over the Ethernet physical layer. This signal can then be made traceable to an external clock.
The STM-4 is a SDH ITU-T fiber optic network transmission standard. It has a bit rate of 622.080 Mbit/s.
References
- ↑ "G.783: Characteristics of synchronous digital hierarchy (SDH) equipment functional blocks". www.itu.int. Archived from the original on 2021-04-05. Retrieved 2021-04-05.