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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 ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inverse Multiplexing
An inverse multiplexer (often abbreviated to inverse MUX or IMUX) allows a data stream to be broken into multiple lower data rate communication links. An inverse multiplexer differs from a demultiplexer because the multiple output streams from the former stay inter-related, whereas those from the latter are unrelated. An inverse multiplexer is the opposite of a multiplexer in that it divides one high-speed link into multiple low-speed links, whereas a multiplexer combines multiple low-speed links into one high-speed link. This provides an end to end connection of several times the data rate available on each of the low rate data links. Note that, as with multiplexers, links are often used in bi-directional pairs and, at either end of the link, an inverse multiplexer will be combined with its reverse (an inverse demultiplexer) and still be called an ''inverse MUX''. Inverse multiplexers are used, for example, to combine a number of Integrated Services Digital Network, ISDN c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SONET
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. However, 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synchronous Digital Hierarchy
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. However, 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 t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LCAS
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 International Telecommunication Union Telecommunication Standardization Sector (ITU-T) is one of the three Sectors (branches) of the International Telecommunication Union (ITU). It is responsible for coordinating Standardization, standards fo ... 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] |
Generic Framing Procedure
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 the 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 is single octet flag-based. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virtual Tributary
Virtual may refer to: * Virtual image, an apparent image of an object (as opposed to a real object), in the study of optics * Virtual (horse), a thoroughbred racehorse * Virtual channel, a channel designation which differs from that of the actual radio channel (or range of frequencies) on which the signal travels * Virtual function, a programming function or method whose behaviour can be overridden within an inheriting class by a function with the same signature * Virtual machine, the virtualization of a computer system * Virtual meeting, or web conferencing * Virtual memory, a memory management technique that abstracts the memory address space in a computer * Virtual particle, a type of short-lived particle of indeterminate mass * Virtual reality (virtuality), computer programs with an interface that gives the user the impression that they are physically inside a simulated space * Virtual world, a computer-based simulated environment populated by many users who can create a person ... [...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. The first standard for faster 10 Gigabit Ethernet was approved in 2002. History Ethernet was the result of research conducted at Xerox PARC in the early 1970s, and later evolved into a widely implemented Physical layer, physical and Data link layer, link layer protocol. Fast Ethernet increased the speed from 10 to 100 megabits per second (). Gigabit Ethernet was the next iteration, increasing the speed to . The initial standard for Gigabit Ethernet was produced by the IEEE in June 1998 as IEEE 802.3z ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
