Abstract: A DVD-R disc which is unusable due to a mechanical error in use can be reused. Recording zones 0 to 2 are sequentially formed from the lead-in side to the lead-out side on the DVD-R disc. When an ECC error occurs due to mechanical damage generated during recording picture information 3 in zone 2 in a DVD-VR format, the readable normal latest log information of log information 2 in zone 1 and log information 1 in zone 0 is moved to the end of zone 2 in which the damage is repaired. After that, recording can be executed in zone 3 next to zone 2.

Abstract: A method and apparatus cancel repeatable run-out (RRO) errors in positioning on a recording medium using a RRO cancellation control voltage. The RRO cancellation includes (a) estimating a rotation period of the recording medium, (b) determining an update interval for the RRO cancellation control voltage based on the estimated rotation period and a desired number of updates to be performed per rotation, (c) updating a value of the RRO cancellation control voltage if a time period passed from a last update is greater than the update interval, and (d) applying the updated RRO cancellation voltage to control the positioning. A phase and a magnitude of the RRO cancellation control voltage may be determined for a RRO frequency range.

Abstract: The present invention generally relates to non-human transgenic animals expressing human cellular markers, including CD20 and/or preferably CD16.

Abstract: A method for detecting and controlling disc tilt in an optical disc mechanism comprising the steps of (A) measuring a 2-dimensional displacement of an optical lens of the optical disc mechanism, (B) extracting an absolute value of a disc tilt angle in the optical disc mechanism based upon the 2-dimensional displacement and (C) controlling deflection of a tilt moving coil according to the absolute value of the disc tilt angle.

Abstract: A high-density optical recording medium and method of recording data on the optical recording medium. The optical recording medium includes a plurality of data recording/reproducing surfaces having reflectances for light passing through a pit area, a land/groove area, and a land/groove area on which data are recorded, of a data recording/reproducing surface included between a light source for emitting light and a recording/reproducing surface selected from the plurality of data recording/reproducing surfaces, the reflectances satisfy the expressions r1?r2?r3 and {(r1?r3)/r1}?0.2, where r1, r2 and r3 are the reflectances of the pit area, the land/groove area and the land groove area on which data are recorded, respectively.

Abstract: An optical recording apparatus includes an optical pickup unit for generating and directing optical signals onto a given optical medium, and for detecting corresponding reflected optical signals from the optical medium; a focus motor for moving a focusing lens on the optical pickup according to a focus signal for adjusting a defocus of the optical signals on the optical medium; and a focus controller for generating the focus signal. During write operations of the optical recording apparatus, the focus controller is for performing write defocus calibration on the given optical medium to determine an optimal write defocus value for the optical medium. If the optical medium has multiple layers, the write defocus calibration is performed on a particular layer of the optical disc toward which write operations are directed. If the optimal defocus write value is different than a starting write defocus value, an updated write defocus value is stored.

Abstract: A device and method for reducing power consumption of an optical drive are proposed. The present invention samples a carrier control signal and then compares the samples of the signals with predetermined threshold signals. According to the comparison result, the present invention increases or decreases an output signal index. The variation of the output signal index is used to control phases of diphase excitation control signals so as to control the rotation direction of a motor or make it stop. The present invention need not output the diphase excitation control signals continuously. It only needs to output a predetermined number of the diphase excitation control signals after the output signal index is increased or decreased. Hence, the present invention reduces the time for outputting the control signals and greatly reduces the power consumption of the optical drive thereby.

Abstract: In order to reduce the cross talk between data recorded in adjacent tracks on a record carrier the encoding of the data stream into code words is controlled using control points. The code words in a first track are altered by selecting that value of the control point that results in code words that differ in as many bit positions as possible from the corresponding bit positions in a second track, where the first track and second track are both adjacent to the same third track. Having opposite bit values in corresponding bit positions on the first and second track results in the lowest contribution of these bit positions to the code words stored in the third track.

Abstract: An optical scanning device (1) is for scanning an information layer (2) by means of a radiation beam (4). The device includes a radiation source (7) for supplying said radiation beam, an objective lens (10) for transforming said radiation beam into a scanning spot (19) at the position of the information layer, and a beam intensity modifier (8) for redistributing the intensity (I2) over the cross-section of said radiation beam in order to change the size of said scanning spot. The beam intensity modifier has an entrance pupil (8a) and an exit pupil (8b). Furthermore, it is arranged so that any ray of said radiation beam entering said beam intensity modifier at a distance r1 from the central ray of that beam reflects at least twice between said entrance and exit pupils that the transverse magnification M of said modifier is defined by a decreasing function of the distance r1.

Abstract: Methods and apparatus are provided for controlling writing and reading of data in an array of A storage fields of a probe-based data storage device in which data is written to and read from the array of storage fields by a corresponding array of probes. One method uses the concept of sub-arrays to provide variable-rate read/write operation. Input data blocks are received for writing to the A-field array, each input data block being writable in A/k0 storage fields where k0 is an integer ?2. For successive groups of k0 blocks, the k0 blocks are written to respective sub-arrays, each of A/k0 storage fields, of the storage field array by selectively writing at one of a series of rates, ranging from 1 block at a time to k0 blocks at a time, in dependence on a desired data write-rate. The blocks can also be read from the sub-arrays by selectively reading at one of a series of rates, ranging from 1 sub-array at a time to k0 sub-arrays at a time, in dependence on a desired data read-rate.

Abstract: In the hologram recording and hologram-record reproduction using a one-dimensional optical modulator, the one-dimensional optical modulator where a plurality of light-modulating pixels are arranged modulates a laser beam to record a digital-data signal on a hologram recording medium, and part of the light-modulating pixels record sync signals in two or more positions on the hologram recording medium with retaining a predetermined interval, thereby improving hindrance to reproduction or readout of information recorded on the hologram recording medium, a decrease in S/N, and so on due to deformation or the like of the hologram recording medium.

Abstract: An optical scanning device (1; 100) for scanning an information layer (4) of an optical record carrier (2; 102). The device comprises a radiation source (11; 111) for generating a radiation beam (12, 15, 20; 112, 115, 120), an objective system (18; 118) for converging the radiation beam on the information layer (4), and an optical filter (200) for regulating the intensity profile of the radiation beam. The filter has an optical axis (119) and comprises a saturable absorber (206) having an absorption that saturates at a threshold incident radiation intensity. For incident radiation beams of intensity less than the threshold, the absorption of the absorber decreases with distance away from the axis.

Abstract: The present invention relates to a method and a corresponding apparatus for recording an information on a recordable optical record carrier (2) by irradiation of a light beam through optical means (3-7) onto said record carrier (2) for forming marks and lands representing said information along an information recording direction (t). To obtain a higher recording density, and thus higher data capacity, it is proposed according to the present invention to use astigmatism for influencing the light beam from the light source (8) to said record carrier (2) during recording of information so as to obtain a light beam having a substantially oval spot profile having a shorter axis in the information recording direction (t), i.e. the tangential direction for an optical disc, compared to the direction (r) orthogonal that to, i.e. the radial direction.

Abstract: A low cost patterned spinning disk is disclosed for achieving relatively rapid discrete optical phase shifts for an optical beam. The invention is particularly useful in a spectral domain optical coherence tomography system. The disk contains stepped patterns of different heights and/or refractive index distribution such that as it spins, an optical beam passing through or being reflected by the disk will experience different discrete optical phase delays. The disk can be operated as a phase shifter or it can be operated in synchronization with an intensity modulating chopper disk or a direct intensity modulation of the light source. The disk can also contain intensity modulating patterns such that both phase shifting and intensity modulation can be achieved at the same time. Various possible methods are also disclosed for the fabrication of the disk.

Abstract: An array-based optical head is configured for read and/or write operations to optical media. In one implementation, a polarizing beam splitter is configured to direct laser light to optical media. A photo-detector array is configured to receive light modulated by reflection off a checkered pattern on the optical media and to create an output signal corresponding to the modulated light.

Abstract: A method and a signal processing unit are proposed, for converting an asynchronous discrete-time signal to a synchronous discrete-time signal by performing sector-based timing recovery. The timing recovery includes aligning an initial portion of the asynchronous discrete-time signal to a first portion of a predetermined signal, and a later portion of the asynchronous discrete-time signal to a second portion of a predetermined signal. Optionally, the method and signal processing unit further perform sector based gain control, and sector-based removal of any dc component.

Abstract: To greatly increase the storage density of a storage apparatus, an electron beam E emitted from a cold cathode 101 is accelerated by an accelerating electrode 102, caused to converge by a convergence electrode 103, deflected by a deflection electrode 104 and applied to a minute region of a storage film 105. The storage film 105 includes, for example, a phase change film 105a. The film is rapidly heated and cooled to change into an amorphous state upon irradiation with an electron beam E with high energy, while being gradually cooled to change into a crystallized state upon irradiation with an electron beam E with approximately intermediate energy, thereby storing data. Upon irradiation with an electron beam E with low energy, the potential difference between a detection electrode 105b and an anode 105c is detected depending on the state, i.e., the amorphous or crystallized state, thereby reading stored data.

Abstract: A method for writing data to an optical medium includes directing intermittent pulses of a beam of ions from an ion source onto an optical medium in a controlled pattern for creating surface features on the optical medium, the surface features representing data. A system for performing this method, according to one embodiment, includes a medium receiving portion for holding an optical medium, an ion source for emitting a beam of ions at the optical medium on the medium receiving portion, and a steering mechanism for directing the ion beam onto the optical medium in a controlled manner. The beam of ions strikes the optical medium in intermittent pulses for creating surface features on the optical medium, the surface features representing data.

Abstract: In the multi colored thermally sensitive recording medium, at least one kind of dye precursor is contained in complex fine particles which contain dye precursor and polymer of multi valence isocyanate compound, further contain 4,4?-diisocyanate-3,3?-dimethyl-1,1?biphenyl and/or polymethylene.polyphenyl.polyisocyanate.

Abstract: A multi-stack optical data storage medium (20) for rewritable recording using a focused radiation beam (30), entering through an entrance face (25) is described. The medium (20) has a substrate (1a, 1b) and an L0 recording stack (2) and an L1 recording stack (3) both comprising a phase-change type L0 and L1 recording layer and the recording stacks are separated by a transparent spacer layer (4). The L0 recording stack (2) is present at a position closest to the entrance face (25) and has an optical transmission of TL0a and TL0c when the phase-change layer respectively is in the amorphous phase and in the crystalline phase. The medium (20) contains pre-recorded information modulated in at least one of: an embossed pregroove (21) in the substrate (1a, 1b), embossed pits in the substrate and recorded phase-change marks in at least one of the recording layers L0 and L1 (6, 11).

Abstract: An intermediate for an optical recording medium, according to the present invention, is an intermediate produced beforehand for manufacturing an optical recording medium that has a central mounting hole formed in a central portion thereof and one or more kinds of functional layers formed on a surface thereof, for enabling at least one of information recording and information reproduction. The intermediate has a provisional central hole, which is smaller in diameter than the central mounting hole, formed in a central portion thereof. This makes it possible to drop resin in the vicinity of the center of the intermediate without using a disk-shaped member, in performing spin coating on the intermediate, whereby it is possible to make the layer of applied resin substantially uniform in thickness.

Abstract: A raw material supplier manufactures raw material for a plastic substrate by means of a raw material manufacturing device. A disk presser manufactures a substrate from the raw material by means of an optical disk manufacturing device, manufactures an optical disk by laminating the substrate sequentially with the recording layer and the reflecting layer, and records predetermined information on the disk by means of an information recording device. The disk presser recovers a pure and lucent plastic substrate from a disk fallen into disuse, so as to supply the substrate to the raw material supplier.

Abstract: A step portion (12) is formed on a table body (11) to be attached to a motor (20), and an ultraviolet curable adhesive as a resin (13) is applied to a mount-place forming position of the table body (11) including the step portion (12), and cured. The table body (11) is attached to the motor (20), and the surface of the resin (13) is cut while rotating a rotating shaft (21) of the motor (20). At this time, the step portion (12) prevents the peeling of the resin (13) against the force of moving the resin (13).

Abstract: Super-resolution technology was proposed for generating marks smaller than the optical resolution in order to record data at high density on the optical disk. However, the achievable high density of the super-resolution technology was limited due to fluctuation of the region exhibiting the super-resolution effect due to the grain size or the molecular size comprising the super-resolution film. However fluctuation in the region exhibiting the super-resolution effect is reduced by utilizing recording marks possessing their own super-resolution effect and also by separating the recording marks from each other.

Abstract: A multi-layered film made of sequentially stacked first dielectric layer, recording layer, record-assist layer, second dielectric layer and first reflection layer on a disc substrate having a concavo-convex structure at least on one surface thereof. An ultraviolet-setting resin layer is formed to cover the multi-layered film. The record-assist layer is controlled in thickness to satisfy the relation d/4<a<3d, or more preferably the relation d/2?a?2d, between the thickness d of the recording layer and the thickness a of the record-assist layer. The stacking order of the multi-layered film may be opposite. In this case, a light-transmitting sheet is provided to cover the multi-layered film via a bonding layer.

Abstract: It is an object of the present invention to provide a data rewritable type optical recording medium which includes a plurality of recording layers and in which data reading characteristics and reproducing characteristics of the respective recording layers can be improved. An optical recording medium according to the present invention includes an L1 recording layer 30 and an L0 recording layer 20 formed on a support substrate 11, and a transparent intermediate layer 12 formed between the L1 recording layer 30 and the L0 recording layer 20.

Abstract: An information recording medium of the present invention includes a recording portion capable of storing information three-dimensionally. The recording portion (3) includes at least one recording layer (1a to 1f), and the recording layer (1a to 1f) contains titanium oxide. It is preferable that titanium oxide is at least one kind of an anatase type and a brookite type. The recording layer (1a to 1f) may be substantially made of titanium oxide, and may contain titanium oxide and a low refractive-index material having a refractive index smaller than that of titanium oxide.

Abstract: To provide an optical information storage medium with high recording/reproducing sensitivity. An optical information storage medium 100 includes a substrate 56 and a multilayer structure 49, which is provided on the substrate 56 and includes at least one storage layer 57. The storage layer 57 includes polydiacetylene or merocyanine and is amorphous.

Abstract: An optical information recording medium includes the first to the n-th information layers (where n is an integer not less than 3) arranged in this order from a laser beam incident side. Each information layer includes a recording layer containing Te, O and M, where M denotes at least one element selected from the group consisting of Al, Si, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, Nb, Mo, Ru, Rh, Pd, Ag, In, Sn, Sb, Hf, Ta, W, Re, Os, Ir, Pt, Au and Bi. Concentrations of oxygen atoms contained in the first to the n-th recording layers, namely C(1) to C(n?1), satisfy the following relationships: C(1)?C(2)? . . . ?C(n?2)?C(n?1), and C(1)?C(n?1). When two information layers are included, the oxygen atom concentration of the first information layer is made larger than that of the second information layer.

Abstract: The invention relates to a record carrier (1) comprising an area for storing data, the record carrier adhering to a pre-defined, standardized condition with respect to a physical parameter. The record carrier comprises parameter information on the physical parameter, which parameter information is of a higher precision than the precision of the physical parameter mentioned in the pre-defined, standardized condition. Using this high precision parameter information, it is possible to derive the exact position of a visible image pixel data making up a label. This parameter information thus enables a recorder to write a visible label on the record carrier according to the invention.

Abstract: The invention relates to a record carrier which comprises multiple sets of recording parameters for a recording process. The recording parameters define a so-called write strategy for converting an information signal to be recorded into a pulsed radiation beam for recording the information on the record carrier. By providing multiple sets of recording parameters, each set related to a specific range of recording speeds, good quality recordings are obtained at various recording speeds.

Abstract: Phase-change compounds, and optical storage recording media, for recording and/or storage of data, comprising such compounds, according to the formula XSbySz; wherein X is selected from the group consisting of K, Rb, Ti, Na, Li, Cs and mixtures thereof; and wherein y is about 1 or about 5, and z is about 1 or about B. Preferably, X is K, y is 5 and z is B. Also provided are optical recording media comprising a layer of the phase-change material and methods of creating a reversible phasechange by irradiating the material with a laser radiation.

Abstract: The apparatus is suitable for managing a data carrier (1) obtaining a fast data transfer from it to the apparatus when the carrier is driven with a constant angular velocity (CAV). It comprises a motor (3) for driving the carrier, an optical head having light source (16) for reading and/or writing data stored form and in it. Furthermore, it comprises means, involving a processor set (50) for determining the frequency of the use of files contained in the data carrier, such that the more frequently used ones are put in a location for a faster transfer. While the transfer is being performed, the motor and the light source arc stopped so that supply energy is economized, which is interesting for a battery-operated apparatus. Application: The invention is well suited for small size R/W optical discs (SFFO).

Abstract: A storage medium can comprise a substrate, a reflective layer disposed on a side of the substrate, and data. The substrate can comprise a thermoplastic and a light-mark formed from at least a portion of light-marking additive mixed with the thermoplastic, wherein an optical property of the light-marking additive at an optical drive read wavelength can change due to being contacted with a mark wavelength. A method for using a storage medium can comprise directing a reading device to detect an inspection area of the storage medium, and wherein the inspection area on an authentic medium has a light-mark in a substrate of the storage medium that forms an optically induced signature. The optically induced signature can be converted to a digital identification signature and the digital identification signature can be verified for authenticity.

Abstract: An optical disc comprising a transparent substrate, an information recording layer, said optical disc comprising a read/write surface and an opposing surface, at least one surface of said disc comprising a surface coating, wherein said at least one surface of said disc shows a change of reflectivity after 100 taber abrasion cycles of no more than 20%, a resistivity no greater than about 9—1013 ohms/square, and a static decay of less than about 0.5 seconds when tested at about 20° C. and 50% relative humidity.

Abstract: A high-density optical recording medium and method of recording data on the optical recording medium. The optical recording medium includes a plurality of data recording/reproducing surfaces having reflectances for light passing through a pit area, a land/groove area, and a land/groove area on which data are recorded, of a data recording/reproducing surface included between a light source for emitting light and a recording/reproducing surface selected from the plurality of data recording/reproducing surfaces, the reflectances satisfy the expressions r1?r2?r3 and {(r1?r3)/r1}?0.2, where r1, r2 and r3 are the reflectances of the pit area, the land/groove area and the land groove area on which data are recorded, respectively.

Abstract: An information recording medium having at least a read only area and a recording and reproducing area is composed of at least: a substrate; a recording layer formed on the substrate so as to record and reproduce information; and a light transmission layer having transparency formed on the recording layer. The information recording medium is further characterized in that a wobbling groove corresponding to the read only area and another wobbling groove corresponding to the recording and reproducing area is formed on the substrate without overlapping with each other, the recording and light transmitting layers are continuously adhered over at least two areas of the read only area and the recording and reproducing area, reflectivity of the recording layer is more than 5%, and a push-pull signal output T3 reproduced from the read only area and another push-pull signal output T4 reproduced from the recording and reproducing area before recording satisfies relations of T3?0.1, T4?0.1 and 1.5?T3/T4?0.5.

Abstract: An information recording medium having at least a read only area and a recording and reproducing area is composed of at least: a substrate; a recording layer formed on the substrate so as to record and reproduce information; and a light transmission layer having transparency formed on the recording layer. The information recording medium is further characterized in that a wobbling groove corresponding to the read only area and another wobbling groove corresponding to the recording and reproducing area is formed on the substrate without overlapping with each other, the recording and light transmitting layers are continuously adhered over at least two areas of the read only area and the recording and reproducing area, reflectivity of the recording layer is more than 5%, and a push-pull signal output T3 reproduced from the read only area and another push-pull signal output T4 reproduced from the recording and reproducing area before recording satisfies relations of T3?0.1, T4?0.1 and 1.5?T3/T4?0.5.

Abstract: Methods and systems for processing signals in a receiver are disclosed herein and may comprise generating at least one channel estimate of a time varying impulse response for at least one of a plurality of received clusters within at least one received signal, where a cluster may comprise an aggregate of continuously processed received multipaths. The generated channel estimate may be transformed to at least one flat fading channel estimate utilizing at least one signal-to-noise ratio optimization algorithm. Complex waveforms, comprising in-phase (I) and quadrature (Q) components, may be processed for the plurality of received clusters within the received signal, and the processed complex waveforms may be filtered. The resulting filtered waveforms may be convolved with the generated channel estimate to generate a convolved input signal. A weight signal for the transforming may be generated, utilizing the at least one signal-to-noise ratio optimization algorithm and the generated convolved input signal.

Abstract: A pilot reception power measuring section 104 measures reception power of a pilot symbol and a data section reception power prediction section 106 predicts reception power of data symbols based on the reception power of the pilot symbol. A power comparison section 107 calculates a difference between this predicted value and the actual reception power of the data symbol, and when the difference is large, a collision position detection section 108 regards the data symbol at the hopping position as colliding with data symbols in other cells. Then, an error correcting decoding section 103 carries out error correcting processing by reducing likelihood of the data symbols detected to be involved in the collision and can thereby improve the error rate characteristic of decoded data.

Abstract: Traffic flow rate control in a network device. Traffic flow may be permitted/restricted based on the role of a device in a network. The traffic flow may be limited on the basis of packets per time period, the limits to be applied on a per-protocol, per-port, and/or per-packet basis.

Abstract: An approach for load balancing is disclosed. A user load is determined based upon data queued for transmission at each of the terminals. In addition, an inroute load corresponding to loading of inroutes serving the terminals is determined. A user-to-inroute distribution that minimizes variation of the inroute load is generated. The user-to-inroute distribution maps the user load to the inroutes. The user load is reassigned to the inroutes based on the determined user-to-inroute distribution. This arrangement has particular applicability to a satellite network that provides data communication services.

Abstract: An approach is provided for obtaining load of a terminal operating in a communication system. A query is transmitted for a cumulative load of the terminal, wherein the terminal belongs to a group of terminals having a common service level. The cumulative load for the terminal is determined based on load information supplied by the terminal and bandwidth allocation information, wherein the cumulative load represents a total amount of data sent over a communication channel of the communication system. The determined cumulative load is provided in response to the query. This arrangement has particular applicability to a satellite network that provides data communication services.

Abstract: A method and system including apparatus for detecting and blocking an invalid request to a target wherein fibre channels interconnect the data processing configuration. A request made from a hub such as a fabric switch to an internal fibre channel arbitrated loop is blocked by substituting IDLE characters for the frames of data included with the request. The substitution of IDLE signals can also occur within an internal fibre channel arbitrated loop system where access is blocked to a confidential data storage system. If the request is legitimate, the data frames are passed to the target and the requested data is transmitted back to the requester. If the request is refused as being an unauthorized request, the data frames are replaced with IDLE characters and no transfer of confidential data occurs.

Abstract: To detect an attack of a network connection, detection of a message containing a sequence number that is within a valid sequence number range is performed, where the message is intended to cause reset of the network connection. The message is dropped, and a counter is incremented to track a number of occurrences of receiving the message in response to detecting that the sequence number in the message is within the valid sequence number range.

Abstract: A method and apparatus for configuring and managing policy configuration associated with a plurality of interfaces of a plurality of devices in a network are provided. This method is executable in a processing system. The processing system includes a processor coupled to a display and user input device. The method comprises displaying an icon corresponding to a device in the network, a plurality of interface indicia associated with traffic flow through the device policy-related information of devices in a network, and, a pair of traffic indicia that indicate a direction of traffic flow with respect to the plurality of interface indicia and the icon. A signal is then accepted from the user input device to indicate selection of an interface indicium. Finally, the policy information of an interface associated with the interface indicium is displayed in accordance with a direction of traffic flow in response to the signal from the user input device.

Abstract: A network communications protocol to allow and points In a computer to communicate their respective requirements for access to a network resource to each other, and to communicate a policy for access to the network resource by said endpoints, and to allow negotiation of access to the network resource for the respective endpoint in accordance with the policy and the requirements information communicated by other endpoints. The network resource may be access to a WAN connection or an Internet connection, or may be a device such as a network printer or network attached storage.

Abstract: A system is provided for controlling the transmission of best-effort filed data or programs on channels from one of plural controllers to one or more client nodes. A program is a group of files and has program information indicating to a client node how to use the files of the program. A channel is a virtual path, wherein a client node can receive program files from different channels in a separable fashion. Channels also have channel information. Multiple controllers are provided which self configure in rank order to control the scheduled transmission of programs files on channels. Client nodes receive announcements of programs and channels from the controllers and selectively subscribe to the channels and programs. Client nodes can be instructed to positively acknowledge receipt of programs and also send back negative acknowledgements for ranges of data words in program files not received. The negative acknowledgements can be consolidated to reduce the number of packets on the network.

Abstract: In accordance with one embodiment of the present invention, a host bus adapter for implementing a first port of a node on a network of nodes interconnected through an intelligent connection system comprising: a transceiver providing a physical interface for the first port; and a protocol controller that transmits a notification to the intelligent connection system on behalf of a remote second port indicating that the second port may have failed when the second port fails to communicate with the first port.

Abstract: In an access portion of a LAN, traffic of a received packet is detected, whether or not the traffic exceeds a predetermined threshold is determined, packet information specific to the received packet is acquired when it is determined that the traffic exceeds the threshold, and an occurrence of a loop connection,is determined when the packet information acquired is compared with packet information previously held and a number of conformity thereof amounts to a predetermined number within a predetermined time.