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P-cycle Protection
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.Asthana, R.; Singh, Y.N.; Grover, W.D.; , "p-Cycles: An overview," IEEE Communications Surveys and Tutorials , vol.12, no.1, pp.97-111, First Quarter 2010 Overview of the p-Cycle In Transport communication networks two methods were developed and introduced for restoration and recovery, one was a ring-based protection and the other was mesh restoration.Claus G. Gruber and Dominic A. Schupke.; , "Capacity-efficient Planning of Resilient Networks with p-Cycles,". 2002. The ring based protection offered a quick recovery time at the expense of higher capacity redundancy, while the mesh restoration offered better capacity-ef ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesh Network
A mesh network is a local area network topology in which the infrastructure nodes (i.e. bridges, switches, and other infrastructure devices) connect directly, dynamically and non-hierarchically to as many other nodes as possible and cooperate with one another to efficiently route data to and from clients. This lack of dependency on one node allows for every node to participate in the relay of information. Mesh networks dynamically self-organize and self-configure, which can reduce installation overhead. The ability to self-configure enables dynamic distribution of workloads, particularly in the event a few nodes should fail. This in turn contributes to fault-tolerance and reduced maintenance costs. Mesh topology may be contrasted with conventional star/tree local network topologies in which the bridges/switches are directly linked to only a small subset of other bridges/switches, and the links between these infrastructure neighbours are hierarchical. While star-and-tree topologi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wavelength-division Multiplexing
In fiber-optic communications, wavelength-division multiplexing (WDM) is a technology which multiplexes a number of optical carrier signals onto a single optical fiber by using different wavelengths (i.e., colors) of laser light. This technique enables bidirectional communications over a single strand of fiber, also called wavelength-division duplexing, as well as multiplication of capacity. The term WDM is commonly applied to an optical carrier, which is typically described by its wavelength, whereas frequency-division multiplexing typically applies to a radio carrier which is more often described by frequency. This is purely conventional because wavelength and frequency communicate the same information. Specifically, frequency (in Hertz, which is cycles per second) multiplied by wavelength (the physical length of one cycle) equals the velocity of the carrier wave. In a vacuum, this is the speed of light, usually denoted by the lowercase letter, c. In glass fiber, it is subs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fiber-optic Communications
Fiber-optic communication is a method of transmitting information from one place to another by sending pulses of infrared light through an optical fiber. The light is a form of carrier wave that is modulated to carry information. Fiber is preferred over electrical cabling when high bandwidth, long distance, or immunity to electromagnetic interference is required. This type of communication can transmit voice, video, and telemetry through local area networks or across long distances. Optical fiber is used by many telecommunications companies to transmit telephone signals, internet communication, and cable television signals. Researchers at Bell Labs have reached a record bandwidth–distance product of over kilometers per second using fiber-optic communication. Background First developed in the 1970s, fiber-optics have revolutionized the telecommunications industry and have played a major role in the advent of the Information Age. Because of its advantages over electrica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Mesh Networks
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. Most optical mesh networks use fiber-optic communication and are operated by internet service providers in metropolitan and regional but also national and international scenarios. They are faster and less error prone than other network architectures and support backup and recovery plans for established networks in case of any disaster, damage or failure. Currently planned satellite constellations aim to establish optical mesh networks in space by using wireless laser communication. History of transport networks Transport networks, the underlying optical fiber-based layer of telecommunications networks, have evolved from Digital cross connect system (DCS)-based mesh architectures in the 1980s, to SONET/SDH (Synchronous Optical Networking/Synchronous Digital Hierarchy) ring archit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Segment Protection
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. Technique Terms #Working path - is the chosen route from source to destination. #Segment protection path - is the working path where the broken segment is using the protected path. #Primary segment - is a segment of the working path. #Protected segment - is the backup path of one segment. #End-to-end protection - is the protection of one segment where is source and destination are also the end points of the backup protection. Saradhi, C.V.; Murthy, C.S.R.; , "Segmented protection paths in WDM mesh networks," High Performance Switching and Routing, 2003, HPSR. Workshop on , vol., no., pp. 311- 316, 24–27 June 2003 doi: 10.1109/HPSR.2003.1226724 Examples In "Working path" animation on the right it can be seen that for ... [...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, 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 ea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MPLS
Multiprotocol Label Switching (MPLS) is a routing technique in telecommunications networks that directs data from one node to the next based on labels rather than network addresses. Whereas network addresses identify endpoints the labels identify established paths between endpoints. MPLS can encapsulate packets of various network protocols, hence the ''multiprotocol'' component of the name. MPLS supports a range of access technologies, including T1/ E1, ATM, Frame Relay, and DSL. Role and functioning In an MPLS network, labels are assigned to data packets. Packet-forwarding decisions are made solely on the contents of this label, without the need to examine the packet itself. This allows one to create end-to-end circuits across any type of transport medium, using any protocol. The primary benefit is to eliminate dependence on a particular OSI model data link layer (layer 2) technology, and eliminate the need for multiple layer-2 networks to satisfy different types of traffic. M ... [...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, 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 e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ASON
was a prestigious hereditary noble title in Japan, used mainly between Asuka and Heian periods. At first, it was the second highest, below ''Mahito'', which was given to members of the Imperial family, but after Heian period it became the highest of the eight noble titles: ''Ason, Mahito, Sukune, Imiki, Michinoshi, Omi, Muraji'', and '' Inagi.'' History The title was created as a part of the eight-'' kabane'' system, proclaimed in 684 during Emperor Tenmu's reign, as its second highest rank. As such, ''Asomi'' was initially given to the highest ranked noble clans whose genealogical origins were often claimed back to imperial princes. Although the clans closest to the Imperial House, that is, descendants of Emperor Keitai, were intended to be promoted to ''Mahito'', the first rank in the original eight ''kabane'' system, this fell out of favor with the nobility. In 802, Prince Yasuyo, a son of Emperor Kammu was designated Yoshimine no Ason Yasuyo, an indication that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ASTN
Automatic Switched Transport Network (ASTN) allows traffic paths to be set up through a switched network automatically. The term ASTN replaces the term ASON ( Automatically Switched Optical Network) and is often used interchangeably with GMPLS (Generalized MPLS). This is not completely correct as GMPLS is a family of protocols, but ASON/ASTN is an optical/transport network architecture. The requirements of the ASON/ASTN architecture can be satisfied using GMPLS protocols developed by the IETF or by GMPLS protocols that have been modified by the ITU. Furthermore, the GMPLS protocols are applicable to optical and non-optical (e.g., packet and frame) networks, and can be used in transport or client networks. Thus, GMPLS is a wider concept than ASTN. Traditionally, creating traffic paths through a series of Network Elements has involved configuration of individual cross-connects on each Network Element. ASTN allows the user to specify the start point, end point and bandwidth required, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IP Address
An Internet Protocol address (IP address) is a numerical label such as that is connected to a computer network that uses the Internet Protocol for communication.. Updated by . An IP address serves two main functions: network interface identification and location addressing. Internet Protocol version 4 (IPv4) defines an IP address as a 32-bit number. However, because of the growth of the Internet and the depletion of available IPv4 addresses, a new version of IP (IPv6), using 128 bits for the IP address, was standardized in 1998. IPv6 deployment has been ongoing since the mid-2000s. IP addresses are written and displayed in human-readable notations, such as in IPv4, and in IPv6. The size of the routing prefix of the address is designated in CIDR notation by suffixing the address with the number of significant bits, e.g., , which is equivalent to the historically used subnet mask . The IP address space is managed globally by the Internet Assigned Numbers Authority ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Communication Networks
A telecommunications network is a group of nodes interconnected by telecommunications links that are used to exchange messages between the nodes. The links may use a variety of technologies based on the methodologies of circuit switching, message switching, or packet switching, to pass messages and signals. Multiple nodes may cooperate to pass the message from an originating node to the destination node, via multiple network hops. For this routing function, each node in the network is assigned a network address for identification and locating it on the network. The collection of addresses in the network is called the address space of the network. Examples of telecommunications networks include computer networks, the Internet, the public switched telephone network (PSTN), the global Telex network, the aeronautical ACARS network, and the wireless radio networks of cell phone telecommunication providers. Network structure In general, every telecommunications network concep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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