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Generic Framing Procedure
{{Unreferenced, date=December 2009 Generic Framing Procedure (GFP) is a multiplexing technique defined by ITU-T G.7041. This allows mapping of variable length, higher-layer client signals over a circuit switched transport network like OTN, SDH/SONET or PDH. The client signals can be protocol data unit (PDU) oriented (like IP/ PPP or Ethernet Media Access Control) or can be block-code oriented (like Fibre Channel). There are two modes of GFP: Generic Framing Procedure - Framed (GFP-F) and Generic Framing Procedure - Transparent (GFP-T): * GFP-F maps each client frame into a single GFP frame. GFP-F is used where the client signal is framed or packetized by the client protocol. * GFP-T, on the other hand, allows mapping of multiple 8B/10B block-coded client data streams into an efficient 64B/65B block code for transport within a GFP frame. GFP utilizes a length/ HEC-based frame delineation mechanism that is more robust than that used by High-Level Data Link Control (HDLC), which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multiplexing
In telecommunications and computer networking, multiplexing (sometimes contracted to muxing) is a method by which multiple analog or digital signals are combined into one signal over a shared medium. The aim is to share a scarce resource - a physical transmission medium. For example, in telecommunications, several telephone calls may be carried using one wire. Multiplexing originated in telegraphy in the 1870s, and is now widely applied in communications. In telephony, George Owen Squier is credited with the development of telephone carrier multiplexing in 1910. The multiplexed signal is transmitted over a communication channel such as a cable. The multiplexing divides the capacity of the communication channel into several logical channels, one for each message signal or data stream to be transferred. A reverse process, known as demultiplexing, extracts the original channels on the receiver end. A device that performs the multiplexing is called a multiplexer (MUX), and a dev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CRC-based Framing
CRC-based framing is a kind of frame synchronization used in Asynchronous Transfer Mode (ATM) and other similar protocols. The concept of CRC-based framing was developed by StrataCom, Inc. in order to improve the efficiency of a pre-standard Asynchronous Transfer Mode (ATM) link protocol. This technology was ultimately used in the principal link protocols of ATM itself and was one of the most significant developments of StrataCom. An advanced version of CRC-based framing was used in the ITU-T SG15 G.7041 Generic Framing Procedure (GFP), which itself is used in several packet link protocols. Overview of CRC-based framing The method of CRC-Based framing re-uses the header cyclic redundancy check (CRC), which is present in ATM and other similar protocols, to provide framing on the link with no additional overhead. In ATM, this field is known as the Header Error Control/Check (HEC) field. It consists of the remainder of the division of the 32 bits of the header (taken as the coefficient ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synchronous Optical Networking
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. SONET and SDH, which are essentially the same, were originally designed to transport circuit mode communications (e.g., DS1, DS3) from a variety of different sources, but they were primarily designed to support real-time, uncompressed, circuit-switched voice encoded in PCM format. The primary difficulty in doing this prior to SONET/SDH was that the synchronization sources of these various circuits were different. This meant that each ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multiplexing
In telecommunications and computer networking, multiplexing (sometimes contracted to muxing) is a method by which multiple analog or digital signals are combined into one signal over a shared medium. The aim is to share a scarce resource - a physical transmission medium. For example, in telecommunications, several telephone calls may be carried using one wire. Multiplexing originated in telegraphy in the 1870s, and is now widely applied in communications. In telephony, George Owen Squier is credited with the development of telephone carrier multiplexing in 1910. The multiplexed signal is transmitted over a communication channel such as a cable. The multiplexing divides the capacity of the communication channel into several logical channels, one for each message signal or data stream to be transferred. A reverse process, known as demultiplexing, extracts the original channels on the receiver end. A device that performs the multiplexing is called a multiplexer (MUX), and a dev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Link Capacity Adjustment Scheme
Link Capacity Adjustment Scheme or LCAS is a method to dynamically increase or decrease the bandwidth of virtual concatenated containers. The LCAS protocol is specified in ITU-T The ITU Telecommunication Standardization Sector (ITU-T) is one of the three sectors (divisions or units) of the International Telecommunication Union (ITU). It is responsible for coordinating standards for telecommunications and Information Commu ... G.7042. It allows on-demand increase or decrease of the bandwidth of the virtual concatenated group in a ''hitless'' manner. This brings ''bandwidth-on-demand'' capability for data clients like Ethernet when mapped into TDM containers. LCAS is also able to temporarily remove failed members from the virtual concatenation group. A failed member will automatically cause a decrease of the bandwidth and after repair the bandwidth will increase again in a hitless fashion. Together with diverse routing this provides survivability of data traffic without requiring ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virtual Concatenation
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. Alternate SONET/SDH concatenation techniques are contiguous concatenation and arbitrary concatenation. Variable bit data streaming Virtual concatenation is considered the primary enhancement to voice optimized SONET/SDH, in order to support the transport of variable bit data streams. Other recent SONET/SDH enhancements include Link Capacity Adjustment Scheme (LCAS), and the Generic Framing Procedure (GFP). In conjunction with LCAS and GFP, Virtual Concatenation gives the advantage of splitting the required bandwidth equally among a set number of sub paths called Virtual Tributaries (VT). The Virtual Concatenation is specified in ITU-T Recommendations G.707 (2007) and G.783 (200 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Video Broadcast
Digital Video Broadcasting (DVB) is a set of international open standards for digital television. DVB standards are maintained by the DVB Project, an international industry consortium, and are published by a Joint Technical Committee (JTC) of the European Telecommunications Standards Institute (ETSI), European Committee for Electrotechnical Standardization (CENELEC) and European Broadcasting Union (EBU). Transmission DVB systems distribute data using a variety of approaches, including: * Satellite: DVB-S, DVB-S2, and DVB-SH ** DVB-SMATV for distribution via SMATV * Cable: DVB-C, DVB-C2 * Terrestrial television: DVB-T, DVB-T2 ** Digital terrestrial television for handhelds: DVB-H, DVB-SH * Microwave: using DTT ( DVB-MT), the MMDS ( DVB-MC), and/or MVDS standards (DVB-MS) These standards define the physical layer and data link layer of the distribution system. Devices interact with the physical layer via a synchronous parallel interface (SPI), synchronous serial interface ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FiCON
FICON (Fibre Connection) is the IBM proprietary name for the ANSI ''FC-SB-3 Single-Byte Command Code Sets-3 Mapping Protocol'' for Fibre Channel (FC) protocol. It is a FC layer 4 protocol used to map both IBM's antecedent (either ESCON or parallel Bus and Tag) channel-to-control-unit cabling infrastructure and protocol onto standard FC services and infrastructure. The topology is fabric utilizing FC switches or directors. Valid rates include 1, 2, 4, 8 and 16 Gigabit per second data rates at distances up to 100 km. FICON was introduced in 1998 as part of fifth generation of IBM System/390 mainframes. After 2011 FICON replaced ESCON in new IBM mainframe deployments because of FICON's technical superiority (especially its higher performance) and lower cost. Protocol internals Each FICON channel port is capable of multiple concurrent data exchanges (a maximum of 32) in full duplex mode. Information for active exchanges is transferred in Fibre Channel sequences mapped as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ESCON
ESCON (Enterprise Systems Connection) is a data connection created by IBM, and is commonly used to connect their mainframe computers to peripheral devices such as disk storage, tape drives and IBM 3270 display controllers. ESCON is an optical fiber, half-duplex, serial interface. It originally operated at a rate of 10MB/s, which was later increased to 17MB/s. The current maximum distance is 43 kilometers. IBM introduced ESCON in September 1990 as part of its System/390 announcement. It replaced the older, slower (4.5MB/s), copper-based, parallel, IBM System/360 Bus and Tag channels technology of 1960-1990 era mainframes. Optical fiber is smaller in diameter and weight, and hence could save installation costs. Space and labor could also be reduced when fewer physical links were required - due to ESCON's switching features. ESCON is being supplanted by the substantially faster FICON, which runs over Fibre Channel. ESCON allows the establishment and reconfiguration of ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gigabit Ethernet
In computer networking, Gigabit Ethernet (GbE or 1 GigE) is the term applied to transmitting Ethernet frames at a rate of a gigabit per second. The most popular variant, 1000BASE-T, is defined by the IEEE 802.3ab standard. It came into use in 1999, and has replaced Fast Ethernet in wired local networks due to its considerable speed improvement over Fast Ethernet, as well as its use of cables and equipment that are widely available, economical, and similar to previous standards. History Ethernet was the result of research conducted at Xerox PARC in the early 1970s, and later evolved into a widely implemented physical and link layer protocol. Fast Ethernet increased the speed from 10 to 100 megabits per second (Mbit/s). Gigabit Ethernet was the next iteration, increasing the speed to 1000 Mbit/s. * The initial standard for Gigabit Ethernet was produced by the IEEE in June 1998 as IEEE 802.3z, and required optical fiber. 802.3z is commonly referred to as 1000BASE-X, whe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frame Check Sequence
A frame check sequence (FCS) is an error-detecting code added to a frame in a communication protocol. Frames are used to send payload data from a source to a destination. Purpose All frames and the bits, bytes, and fields contained within them, are susceptible to errors from a variety of sources. The FCS field contains a number that is calculated by the source node based on the data in the frame. This number is added to the end of a frame that is sent. When the destination node receives the frame the FCS number is recalculated and compared with the FCS number included in the frame. If the two numbers are different, an error is assumed and the frame is discarded. The FCS provides error detection only. Error recovery must be performed through separate means. Ethernet, for example, specifies that a damaged frame should be discarded and does not specify any action to cause the frame to be retransmitted. Other protocols, notably the Transmission Control Protocol (TCP), can notic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
High-Level Data Link Control
High-Level Data Link Control (HDLC) is a bit-oriented code-transparent synchronous data link layer protocol developed by the International Organization for Standardization (ISO). The standard for HDLC is ISO/IEC 13239:2002. HDLC provides both connection-oriented and connectionless service. HDLC can be used for point-to-multipoint connections via the original master-slave modes Normal Response Mode (NRM) and Asynchronous Response Mode (ARM), but they are now rarely used; it is now used almost exclusively to connect one device to another, using ''Asynchronous Balanced Mode'' (ABM). History HDLC is based on IBM's SDLC protocol, which is the layer 2 protocol for IBM's Systems Network Architecture (SNA). It was extended and standardized by the ITU as LAP (Link Access Procedure), while ANSI named their essentially identical version ADCCP. The HDLC specification does not specify the full semantics of the frame fields. This allows other fully compliant standards to be derived fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
