PATENT ABSTRACT
Multiplexing-technology based large-capacity transmission requires the installation of many types of interface card. In addition, supporting a redundant configuration for preventing data communication from being interrupted requires the devices and cards more than double those required for the production system. An optical communication card includes multiple optical signal transmission/reception units, main signal processing units corresponding to the optical signal transmission/reception units and required for a multiplexed system, and a connection selection unit that can switch among multiple optical transmission lines, and each of the main signal processing units includes multiple function units and a function selection unit.

PATENT DESCRIPTION
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to an optical communication card having multiple functions and to a communication device. 
         [0002]    The recent widespread use of the optical communication technology in various fields, such as the Internet and optical phones, requires an optical transmission system to have an extended, long transmission path and a large-capacity transmission capability. A variety of optical communication cards are required to implement these requirements. 
         [0003]    In general, the optical switch function, capable of directly path-switching a large capacity of optical signals, is efficient on a transmission line. In a long-distance transmission system, the longer the propagation distance becomes, the more data errors are generated during signal propagation. To solve this problem, the error correction function, called the FEC (Forward error correction) function, is provided to allow the receiving side to correct data without retransmitting the data even if a data error is generated, thereby implementing optical transmission in a long-distance communication. 
         [0004]    An increase in the transmission capacity is implemented by the multiplexing technology such as a time-division multiplexing device or a wavelength-division multiplexing device and, today, an optical transmission system having the transmission capacity of 40 Gbps or 100 Gbps has been developed. However, a time-division multiplexing device and a wavelength-division multiplexing device are installed independently and so there is a need for a layer integration device having various functions for reducing the capital investment. 
         [0005]    In general, the layer integration device described above comprises a transponder card having the function to connect to an opposed device, the wavelength conversion function, and the FEC function; and a wavelength multiplexing card having the wavelength multiplexing function. The layer integration device further comprises a switch card having the de-multiplexing function necessary for a time-division multiplexing device; and an interface card connected to the switch card and to the opposed device. In the conventional configuration, the signal accepted by the interface card is transmitted to the switch card and is de-multiplexed by the switch card and, after being cross-connected, the signal is multiplexed again and is transmitted to another interface card. This configuration requires many types of communication cards. For example, JP-A-2006-166037 describes the configuration in which there is an optical switch circuit between the optical transmitter/receiver and multiple transponders and, in addition, multiple cards are required according to a difference in the switching method. In addition, such a configuration requires a communication carrier to provide a redundant configuration to avoid an interruption in the data transmission. To solve this problem, device duplication, or card configuration duplication described in JP-A-2006-41921, is employed to implement a redundant configuration in both the client side (user side) and the line side (provider side). 
       SUMMARY OF THE INVENTION 
       [0006]    Although the function processed by the transponder card and the function processed by the interface card are similar, the conventional layer integration device must have both cards. To allow both cards to share the function, the layer integration device must have a backplane installed therein for communication via the back plane, making the configuration complex. 
         [0007]    Another problem is that the need for device duplication and card duplication for building a redundancy configuration requires a communication carrier to make a two-fold investment. 
         [0008]    In view of the foregoing, there is a need for a layer integration device to automatically recognize the settings specified by a maintenance engineer and the signals received by the device for providing various services and to ensure redundancy and expandability while still allowing a single card to provide multiple functions. 
         [0009]    To solve the problems described above, multiple signal transmission/reception units (main signal transmission/reception units) each having the optical signal transmission and reception function and multiple main signal processing units each capable of selecting the transponder function, interface function, and so on are installed on a communication card. Multiple signal processing units may be connected in the card or may be connected to a signal processing unit on another card. 
         [0010]    For example, when one signal processing unit performs the accommodation signal processing function, another signal processing unit performs the FEC processing function, and the two main signal processing units may be connected via the connection selection unit, this configuration allows a transponder to be built with a single communication card. In addition, when one main signal processing unit performs the accommodation signal processing function, another two main signal processing units perforin the FEC processing function, and the three main signal processing units are connected via the connection selection unit, redundancy may be introduced into the FEC processing function on a single communication card. Multiple communication cards, if installed in the device, allow the interface configuration across the communication cards. 
         [0011]    An example of a communication card of the present invention is an optical communication card comprising a first signal transmission/reception unit that performs optical-electrical signal conversion for a signal received from an external unit to generate a first signal; a second signal transmission/reception unit that performs optical-electrical signal conversion for a second signal and transmits the converted signal to an external unit; a first signal processing unit that comprises a plurality of types of function units and a function selection unit that selects a function unit to be operated from the plurality of types of function units and that is connected to the first signal transmission/reception unit to process the first signal; a second signal processing unit that comprises a plurality of types of function units and a function selection unit that selects a function unit to be operated from the plurality of types of function units and that is connected to the second signal transmission/reception unit to process the second signal; and a connection selection unit that manages a connection between the first signal processing unit and the second signal processing unit. 
         [0012]    An example of a communication device of the present invention is a communication device that has a communication card and a control unit that controls the communication card wherein the communication card comprises a first signal transmission/reception unit that performs optical-electrical signal conversion for a signal received from an external unit to generate a first signal; a second signal transmission/reception unit that performs optical-electrical signal conversion for a second signal and transmits the converted signal to an external unit; a first signal processing unit that comprises a plurality of types of function units and a function selection unit that selects a function unit to be operated from the plurality of types of function units and that is connected to the first signal transmission/reception unit to process the first signal; a second signal processing unit that comprises a plurality of types of function units and a function selection unit that selects a function unit to be operated from the plurality of types of function units and that is connected to the second signal transmission/reception unit to process the second signal; a connector that transmits the first signal to a backplane; and a connection selection unit that manages a connection between one of the second signal processing unit and the connector and the first signal processing unit, and the control unit transmits control information on the connection to the connection selection unit. The communication device may comprise multiple communication cards and a switch that controls the connection among the multiple communication cards. 
         [0013]    Layer integration implemented on a single card ensures redundancy and expandability while providing multiple functions. This capability lowers the cost of the layer integration device. Signal processing functions corresponding to various needs may be set on a single card arbitrarily by selecting the maintenance/management method from the setting device of an external terminal or by automatically judging accommodation signals. A maintenance engineer, who maintains the device, selects the transponder or interface configuration via the setting device to set up any configuration on a single card. When a redundant configuration is required, one of the multiple main signal transmission/reception units is selected as the client side and a main signal transmission/reception unit other than the one is selected as the client side is selected as the line side in a single card and, among the main signal processing units corresponding to the main signal transmission/reception units, the main signal processing unit corresponding to the client side and the main signal processing unit corresponding to the line side are arbitrarily connected by the connection selection unit to build a redundant configuration. This configuration reduces the card types a carrier must install and, in addition, allows a redundant configuration to be built with a signal card, significantly reducing the communication carrier&#39;s capital investment. 
         [0014]    Other objects, features and advantages of the invention will become apparent from the following description of the embodiments of the invention taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]      FIG. 1  is a diagram showing an example of the configuration of an optical communication card. 
           [0016]      FIG. 2  is a diagram showing an example of the functional blocks of a main signal processing unit installed in the optical communication card. 
           [0017]      FIG. 3  is a diagram showing an example of the general configuration of a network to which a layer integration device is applied. 
           [0018]      FIG. 4  is a diagram showing an example of the general configuration of the layer integration device. 
           [0019]      FIG. 5  is a diagram an example of the manual control sequence of the layer integration device. 
           [0020]      FIG. 6  is a diagram showing an example of the automatic control sequence of the layer integration device. 
           [0021]      FIG. 7  is a diagram showing an example of the layer integration device configured only by a single optical communication card. 
           [0022]      FIG. 8  is a diagram showing an example of the layer integration device configured by two or more optical communication cards and a switch card. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0023]    An optical transmission system using an optical communication card of the present invention will be described below. Note that the present invention is not limited by the embodiment described blow. 
         [0024]      FIG. 3  is a diagram showing an example of the configuration of an optical communication network to which a layer integration device of this embodiment is applied. Installing a layer integration device  301  ( 301 - a ,  301 - b ), which has an optical communication card, in an optical communication network, composed of an optical network fiber  302  and an optical transmission device  303 , allows a different-layer communication network, such as a router  304  and an SDH device  305 , to be included in a conventional optical communication network. 
         [0025]      FIG. 1  is a configuration diagram and a functional block diagram of the optical communication card in this embodiment  FIG. 2  is a functional block diagram of a main signal processing unit. An optical communication card  101  shown in  FIG. 1  has multiple optical signal transmission/reception units  102  ( 102 - 1 - 102 -N). The optical signal transmission/reception unit  102  has the conversion function to convert an optical signal and an electrical signal, and each optical signal transmission/reception unit  102  has a transmission unit and a reception unit. The optical communication card  101  further comprises main signal processing units  103  ( 103 - 1 - 103 -N), one for each optical signal transmission/reception unit  102  ( 102 - 1 - 102 -N). As shown in  FIG. 2 , the main signal processing unit  103  comprises an accommodation signal processing function unit  201  that monitors and supervises an accommodation signal; a mapping function unit  202  that converts a received signal to a different-protocol signal for conversion to multiple types of protocol; an interface function unit  203  that has the interface function; an FEC processing function unit  204  that processes Forward Error Correction for correcting data errors; and a function selection unit  205  that selects a function inside the device. All function units need not be provided but a part of them may be included in the configuration. And, when the maintenance engineer specifies settings or when the device automatically makes judgment based on the accommodation signal, the function operation of each function unit is implemented. The optical communication card  101  further comprises a connection selection unit  104  that selects a path freely in the card; and a backplane (hereinafter called BP) interface connector  106  that communicates with a unit outside the card. Among the function units are provided main signal transmission lines  107 ,  108 , and  109  through which the main signal propagates. The optical communication card  101  further comprises a control unit  105  that manages the usage status information on the main signal transmission/reception units based on the control information, which will be described later, and the in-card connection setting information such as the configuration information on the connection among the main signal processing units, transmits and receives control information to and from the elements (main signal transmission/reception units, main signal processing units, etc.) in the optical communication card, and transmits an alarm to an external device when an abnormal condition is generated in each element; and control signal transmission lines  110 ,  111 ,  112 , and  113  for propagate control signals. 
         [0026]      FIG. 4  is a diagram showing the configuration of the layer integration device in this embodiment. The layer integration device  301 , which has an in-device BP  401  that allows communication among various cards, may include a control card  402 , a switch card  405 , and optical communication cards  101  ( 101 - 1 - 101 -N) in this embodiment. The in-device BP  401  comprises a control signal BP transmission line  404  for propagating a control signal between the control card  402  and each card; and a main signal BP transmission line  407  for propagating a main signal between the optical communication cards  101  and the switch card  405 . The control card  402  and the switch card  405  have a control card BP interface connector  403  and a switch card BP interface connector  406 , respectively, for transmitting and receiving signals to and from the in-device BP  401 . From an external terminal  408  to the control card  402  via an external terminal control signal transmission line  409 , the maintenance engineer transmits port settings and control information for selecting and executing the transponder function or, via the switch card  405 , the interface function. The control information has the information on which of the main signal transmission/reception units is to be allocated to the port of the client side and the line side and on the connection configuration among the ports. This allows the maintenance engineer to freely select the configuration to be used for operation in the layer integration device  301 . 
         [0027]      FIG. 5  is a diagram showing an example of the manual control sequence of the layer integration device performed by the maintenance engineer. When control information  501  is transmitted from the external terminal  408  to the control card  402 , the control card  402  transmits control information  502  to the required optical communication card  101  based on the control information  501 . The control unit  105  in the optical communication card  101 , which has received the control information  502 , establishes the connection configuration with one of the main signal processing units  103  or between the main signal processing unit  103  and the BP interface connector  106 . Via this connection, a connection is ruction  503  is transmitted to the connection selection unit  104 , and the control unit  105  confirms a connection result  504 . Next, based on the confirmation by the control unit  105 , a signal processing function selection instruction  505  is transmitted to the main signal processing unit  103 . After that, the main signal processing unit  103  returns a processing function selection result  506  to the control unit  105 , and the control unit  105 , which has confirmed the main signal processing function, transmits a port setting instruction  507 , which enables the optical signal transmission/reception unit  102 , to the optical signal transmission/reception unit  102 . The port setting refers to the selection of an available port according to the configuration to be started for operation. For example, a client port and a line port are allocated to free ports. On the other hand, the control unit  105 , which has received a port setting result  508 , transmits a setting result  509  of the final optical communication card  101  from the control unit  105  to the control card  402  and, in addition, the control card  402  transmits setting information  510  on all cards to the external terminal  408 . This allows the maintenance engineer to confirm the operation configuration of the layer integration device  301 . The sequence described above allows the configuration of the layer integration device  301  to be set from the external terminal. 
         [0028]      FIG. 6  is a diagram showing the automatic control sequence of the layer integration device performed through automatic recognition. When one of the optical signal transmission/reception units  102 -K in the optical communication card  101  receives an optical signal, port usage information  601 -K is transmitted to the control unit  105 . The control unit  105  returns a port setting instruction  507 -K to perform port setting. In this port setting, a port is selected according to the protocol of the signal to be connected. The control unit  105 , which has received a port setting result  508 -K, transmits a conversion instruction  602 -K, which converts an optical signal to an electrical signal, to the optical signal transmission/reception unit  102 -K, which converts the optical signal to an electrical signal  603 -K and transmits the converted signal to the main signal processing unit  103 -K. The main signal processing unit  103 -K transmits main signal information  604 -K, included in the electrical signal  603 -K, to the control unit  105 . The control unit determines the optimal operation configuration method based on the main signal information  604 -K. Here, the optimal operation configuration refers to the configuration in which, for a line side port and a client side port to be set based on the control information, the interconnection is determined according to the protocol of the line side port and the protocol of the client side port. For example, the connection ports are decided by connecting the line side port and the client side port when the signal of both sides is transmitted according to the OC-192 protocol or the G-bit Ether protocol, or by selecting a free port if there is no signal and, between them, the transponder is configured. After deciding the optimal configuration, the control unit  105  transmits a connection instruction  503  to the connection selection unit  104 . When the connection result  504  is confirmed, the control unit  105  transmits a signal processing function selection instruction  505 -L to another main signal processing unit  103 -L to be connected. When the processing function selection result  506 -L of the main signal processing unit  103 -L is confirmed, the control unit  105  transmits a port setting instruction  507 -L to the optical signal transmission/reception unit  102 -L. After that, the port setting result  508 -L is returned to the control unit  105  to automatically establish the connection configuration. When the setting result  509  of the final optical communication card  101  is transmitted from the control unit  105  to the control card  402  and, when the control card  402  transmits the setting information  510  on all cards to the external terminal  408 , the maintenance engineer can recognize the operation configuration of the layer integration device  301 . 
         [0029]    In this embodiment, one of the functions of the main signal processing unit  103  may be selected for operation from the multiple function units of the main signal processing unit by means of the function selection unit to change the processing arbitrarily.  FIG. 7  is a diagram showing the layer integration device  301  configured by using one optical communication card  101  in this embodiment. In this configuration, when the client side is allocated to the optical signal transmission/reception unit  102 - 1  and the line side is allocated to the optical signal transmission/reception unit  102 - 2 , the interface function unit  203  is selected as the function of the main signal processing unit  103 - 1 , and the FEC processing function unit  204  is selected as the function of the main signal processing unit  103 - 2  manually or automatically and then the main signal processing units are connected by the connection selection unit  104 . In this way, the transponder configuration may be implemented in a single card. 
         [0030]    In this embodiment, input/output redundancy is also possible even when a single optical communication card  101  is installed in the layer integration device. In  FIG. 7 , if redundancy is required for the line side, the production system and the backup system may be switched simply by allocating the optical signal transmission/reception unit  102 -N to the backup system on the line side, by causing the main signal processing unit  103 -N to select the FEC processing function unit  204 , and by changing the connection between the main signal processing units by the connection selection unit  104  from the optical signal transmission/reception unit  102 - 2  to the optical signal transmission/reception unit  102 -N. This method allows a redundant configuration to be implemented on both client side and line side. In addition, even when the optical communication card is singly installed in the layer integration device, a switchable, redundant configuration may be implemented by separating the port and the connection configuration on the client side and line side between the production system and the backup system. 
         [0031]    In addition, when multiple optical communication cards are used in this embodiment, the configuration may be selected freely between the multiple cards.  FIG. 8  is a diagram showing the layer integration device in which the switch card and multiple optical communication cards are installed. The switch card  405  comprises a large-capacity connection selection unit  801  and a control unit  802  that controls the large-capacity connection selection unit  801 , and further comprises main signal transmission lines  803  for propagating the main signal and control signal transmission lines  804  and  805  for propagating the control signals. The following describes a case n which the client side is allocated to the optical signal transmission/reception unit  102 - 1 - 1  of the optical communication card  101 - 1  and the line side is allocated to the optical signal transmission/reception unit  102 -M- 1  of the optical communication card  101 -M in this embodiment as shown in  FIG. 8 . The transponder configuration is implemented in such a way that the main signal processing unit  103 - 1 - 1  selects the interface function, the main signal processing unit  103 - 1 - 1  is connected to the BP via the connection selection unit  104 - 1 , the BP is connected to the optical communication card  101 -M via the switch card  405 , the FEC function is added by the main signal processing unit  103 -M- 1 , and the signal is transmitted to the optical signal transmission/reception unit  102 -M- 1 . In this configuration, even when the functions must be exchanged on a card basis, free ports may be used freely and a redundant configuration may be implemented on a card basis. 
         [0032]    The interface function and the transponder function may also be implemented in a single card in this embodiment. In the optical communication card  101 - 1 , the main signal processing unit  103 - 1 - 1  implements the interface function and the main signal processing units  103 - 1 - 2  and  103 - 1 -N set up the transponder configuration as shown in  FIG. 8 , thus allowing the multiple-function configuration, which would require multiple cards in the prior art, with a single card. 
         [0033]    It should be further understood by skilled in the art that although the foregoing description has been made on embodiments of the invention, the invention is not limited thereto and various changes and modification may be made without departing from the spirit of the invention and the scope of the appended claims.