摘要:
A communication system and method for compressing data in a transmission system wherein multiplexed channels are transported over a transmission network of the type comprising a plurality of switching nodes interconnected by connection lines, the exchange of data signals carried out by switching the channels in the network between two exchange telephone devices, and each of the multiplexed channels transporting data bytes representing the data signals from one source exchange telephone device to one destination exchange device during an exchange of information therebetween through the intermediary of a compression/decompression device. The method comprises the steps of comparing, for each multiplexed channel, the signal value associated to each one of a plurality of “n” consecutive data bytes to a predetermined threshold; deleting, in case said signal value for all said “n” data bytes is less than the predetermined threshold, all bits which are not necessary to represent the signal value from each of the “n” data bytes; building a compression frame by concatenating either the “n” data bytes when they are not modified or the “n” modified data bytes when bits have been deleted therefrom, and adding to each of said groups an identifier indicating whether said data bytes are modified or not before transmitting said compression frame over said transmission network. Decompressing the frame by determining the identifier value indicating the composition of the bytes; removing the identifier from the bytes; loading the bytes into a buffer and transmitting the bytes to a destination exchange telephone device.
摘要:
In a packet switched communications system an incoming real-time packet is imbedded after the next block of data of the non-real-time packet being transmitted. This object is accomplished by transmitting each packet along with at least a 1-byte trailer which is used to indicate the packet type, whether the current block of non real time data is preempted or whether the current block of non real time data is resumed.
摘要:
Process for transmitting compressed voice circuits over a packet switching network of the type comprising a plurality of switching nodes (SW-1 to SW-7) interconnected by connection lines and including at least an end switching node (SW-1) connected to a source exchange telephone device (PABX A) and another end switching node (SW-3) connected to a destination exchange telephone device (CX), and comprising the steps of receiving from the source exchange telephone device a sequence of uncompressed frames wherein each frame contains n slots containing each J bytes respectively associated to J voice circuits, compressing the data bits of each voice circuit in order to build a packet containing J compressed voice circuits, and providing this packet to the end switching node for transmission to the destination exchange telephone device.
摘要:
A method and system for optimizing data link occupation in a multipriority data traffic environment by using data multiplexing techniques over fixed or variable length data packets being asynchronously transmitted. The packets are split into segments including both a segment number and a packet number. The segments are dispatched, on a priority basis, over available links or virtual channels based on a global link availability control word indications, which control word is dynamically adjusted according to specific predefined conditions.
摘要:
A multipurpose data communication network node for interconnecting both ATM and Variable Length (VL) input/output trunks with all combinations of node input versus output trunk connections. The network node includes ATM/VL Receive Adapters and ATM/VL Transmit Adapters, interconnected via a Switching device (44) operating on ATM like packets (i.e. ATM cells) only. The receive adapter includes means (41, 43) for deriving switchable cells from VL traffic possibly including ATM packets and provided over an input VL trunk and means (45, 46) for deriving switchable cells from ATM packets provided on input ATM trunk. The transmit adapter, includes means (47, 48) for reconstructing VL traffic to be fed onto an output VL trunk, and means (49, 50) for reconstructing ATM traffic to be fed onto an output ATM trunk; both means (47, 48) and (49, 50) being fed with switchable cells irrespective of the traffic origin, being it from VL or ATM trunks.
摘要:
A high performance data packet buffering method and a programmable data communication adapter for high speed packet transmission networks are disclosed. The line adapter includes programmable processing means, for receiving and transmitting data packets of fixed or variable length. This system is characterized in that it comprisesmeans for buffering (132) said data packets,means for identifying said buffering means and said data packets in said buffering means,means for queueing (FIG. 15) in storing means (131) said identifying means in a single instruction,means for dequeueing (FIG. 16) from said storing (131) means said identifying means in another single instruction,means for releasing said buffering means,Each instruction comprises up to three operations executed in parallel by said processing means:an arithmetical and logical (ALU) operation on said identifying means,memory operation on said storing means, anda sequence operation.
摘要:
Currently, routing algorithms compute all the available paths in the network, from a source node to a destination node before selecting the optimal route. The route computation is often time and resource consuming. Some paths are not acceptable due to the particular geographical configuration of the network. In the real world, large transport networks are not fully meshed. The present invention is based on the observation that networks are usually built around a hierarchical structure. A set of nodes, interconnected by high throughput lines, are used to build a `Backbone` (401) with a high degree of meshing to allow the redundancy and reliability required by the user. The other nodes or `local` nodes (404) are attached to one or several backbone nodes. It is the network designer responsibility, at the configuration time to define for each node what is its attribution: backbone (402) or local node (404). The list of the node attributions appears in the topology table (306) and is updated each time a node is added to or dropped from the network. The routing algorithm can take advantage of the particular network topology to drastically reduce the complexity of paths computation. For a given connection, only a limited number of nodes are eligible and are taken in account by the algorithm in the optimal route search. The object of the invention is to split the network into backbone and local nodes to speed up the path selection.
摘要:
A method and system for optimizing transmission links bandwidth utilization in an Asynchronous Transfer Mode (ATM) packet switching network including switching nodes interconnected by high speed transmission links, said network being made to transport user data traffic including PTM traffic organized into variable length packets, each packet comprising a variable length data payload and an original fixed length PTM packet header. The original PTM header is converted into an ATM-like header including a flag (F) identifying the packet as being a PTM packet, a label indication made to orient the currently-considered PTM packet within the ATM network nodes, a count (CNT) field for storing the PTM payload length indication therein to enable locating the PTM payload end position and a Header Error Control (HEC) field for storing an ATM-like error control byte (HEC) therein, which enables transporting the PTM packets over the ATM network links without having to chop the PTM payload into predefined fixed length segments by adding dummy bits to the last segment if required.
摘要:
A system for coding voice signal to optimize bandwidth occupation in a High Speed Packet Switching network while ensuring best voice transmission quality.The voice signal is first encoded using a conventional GSM like RPE/LTP coder providing first sub-frames of coded signal and tagging these first sub-frames as being non-discardable. In addition, a convenient difference between an RPE/LTP provided signal and a corresponding synthesized image is performed (see 36) and is also block encoded into second sub-frames which second sub-frames are tagged as being discardable sub-frames. Said second sub-frames when concatenated to corresponding first sub-frames provide so-called multirate frames. Then, when transmitting said multirate frames over the High Speed packet switching network, dropping discardable tagged data enables solution network congestion situations in any network node and at random with no significant disturbing effect over the voice communication operation.
摘要:
A packet switching communication system is improved by using a packet header structure which does not require a fixed format. The packet header comprises a chain of 2 byte command/data segments. Each command/data segment contains generic bits and a routing field. One of the generic bits (bit 1) allows the header to be extended with another command/data segment.