Abstract:
Power consumption on GMPLS controlled networks can be reduced by cutting power consumption on spare paths that are not normally used. To achieve power consumption reduction, in the path setting process, a path is calculated while taking the power saving capability of each interface into account, and the applicable interface is set to the power-saving state when setting the spare path. When the spare path was set to the operating state, then the power-saving state on the applicable interface was canceled so that interface could operate normally.

Description:
CLAIM OF PRIORITY 
       [0001]    The present application claims priority from Japanese patent application JP 2007-250367 filed on Sep. 27, 2007, and JP 2008-176452 filed on Jul. 7, 2008, the contents of which are hereby incorporated by reference into this application. 
       FIELD OF THE INVENTION 
       [0002]    This invention relates to power control of a spare path for a communication equipment. 
       BACKGROUND OF THE INVENTION 
       [0003]    A communication equipment with a spare path as shown in JP-A No. Hei-7(1995)-95132 can reduce overall power consumption in the equipment by lowering power consumption of the interface board for the spare path. 
         [0004]    A method disclosed in RFC3473 describes a method for notifying equipments on whether a current path is in a main path or a spare path by utilizing a GMPLS (generalized multiprotocol label switching) signaling protocol. 
       SUMMARY OF THE INVENTION 
       [0005]    The method disclosed in JP-A No. Hei-7(1995)-95132 describes no technique for deciding to switch from the main path to the spare path and cannot inform other equipments occurrence of a fault in the interface board of one equipment. Therefore, in that method, interface boards which are not directly connected to the fault-occurring equipment could not become lower power consumption status. 
         [0006]    The technology disclosed in RFC3473 is capable of giving notification that a current path is in the spare path but contains no information regarding power control of the interface board. Moreover this technology was not able to decide whether to set the interface board for the spare path to the power-saving state. 
         [0007]    This invention is capable of lowering power consumption during the standby state by installing power supply controlling unit to turn the power to each component in the optical interface on and off, and by turning the power off to all or a portion of the interfaces that are in a non-operational state. 
         [0008]    The GMPLS control unit contains a power control capability table showing the power regulation performance in each interface unit of each optical switch, as well as a network topology table showing the connection status between optical switches. While setting paths for the spare LSP (label switched path), the GMPLS control unit also adds restrictions to the topology so that the path does not use the same nodes as the main LSP, and sets an allowable recovery time as a limiting condition for the service utilizing the LSP, and employs a path with a large power saving effect as the spare path. 
         [0009]    When switching to the spare path after a fault occurs on the main path, the GMPLS control unit instructs each GMPLS control unit on the spare path to set the spare path to operating status. Each of these GMPLS control units sets the power supply controlling units for each interface along the spare LSP to normal operating status, and also cuts off alarms issued from the interface units while within the allowable recovery time. 
         [0010]    This invention is capable of achieving power saving on the entire network system which sets redundant (main and spare) LSP along multiple equipments LSP, by setting all interface units on the spare LSP to the power-saving state, and, when a fault occurs on the main LSP, setting spare LSP to the normal state by cancelling the power-saving state in all interface units along the spare LSP. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a drawing showing the network system of the first embodiment; 
           [0012]      FIG. 2  is a structural drawing of the optical switching unit  20 ; 
           [0013]      FIG. 3  is a structural drawing of the optical interface unit  206 ; 
           [0014]      FIG. 4  is a drawing showing the structure of the GMPLS control unit  30 ; 
           [0015]      FIG. 5  is a diagram showing the path setting process sequence; 
           [0016]      FIG. 6  is a diagram showing the state change processing sequence for the spare path; 
           [0017]      FIG. 7  is a drawing showing the data structure of the path message; 
           [0018]      FIG. 8  is a diagram of the data structure of the network topology table; 
           [0019]      FIG. 9  is a drawing showing the data structure for the power control capability table; 
           [0020]      FIG. 10  is a drawing showing a switching state control table; 
           [0021]      FIG. 11  is a drawing showing the IF power state control table; 
           [0022]      FIG. 12  is a drawing showing the data structure of the path state control table  330 ; 
           [0023]      FIG. 13  is a drawing showing the structure of the service type recovery time control table; 
           [0024]      FIG. 14  is a flow chart showing the path calculation process  3500 ; 
           [0025]      FIG. 15  is a flow chart of the IF state setting process  3600  during the path setting; 
           [0026]      FIG. 16  is a flow chart of the IF state setting process  3700  during changing of the path state; 
           [0027]      FIG. 17  is a drawing showing the IF power state control table for the GMPLS control unit  30   d  in step  503 ; 
           [0028]      FIG. 18  is a drawing showing the switching state control table for the GMPLS control unit  30   d  in step  504 ; 
           [0029]      FIG. 19  is a drawing showing the IF power state control table for the GMPLS control unit  30   a  in step  506 ; 
           [0030]      FIG. 20  is a drawing showing the switching state control table for the GMPLS control unit  30   a  in step  507 ; 
           [0031]      FIG. 21  is a drawing showing the IF power state control table for the GMPLS control unit  30   d  in step  512 ; 
           [0032]      FIG. 22  is a drawing showing the switching state control table for the GMPLS control unit  30   d  in step  513 ; 
           [0033]      FIG. 23  is a drawing showing the IF power state control table for the GMPLS control unit  30   c  in step  515 ; 
           [0034]      FIG. 24  is a drawing showing the switching state control table for the GMPLS control unit  30   c  in step  516 ; 
           [0035]      FIG. 25  is a drawing showing the IF power state control table for the GMPLS control unit  30   b  in step  518 ; 
           [0036]      FIG. 26  is a drawing showing the switching state control table for the GMPLS control unit  30   b  in step  519 ; 
           [0037]      FIG. 27  is a drawing showing the IF power state control table for the GMPLS control unit  30   a  in step  521 ; 
           [0038]      FIG. 28  is a drawing showing the switching state control table for the GMPLS control unit  30   a  in step  522 ; 
           [0039]      FIG. 29  is a drawing showing the IF power state control table for the GMPLS control unit  30   d  in step  607 ; 
           [0040]      FIG. 30  is a drawing showing the switching state control table for the GMPLS control unit  30   d  in step  608 ; 
           [0041]      FIG. 31  is a drawing showing the IF power state control table for the GMPLS control unit  30   c  in step  609 ; 
           [0042]      FIG. 32  is a drawing showing the switching state control table for the GMPLS control unit  30   c  in step  610 ; 
           [0043]      FIG. 33  is a drawing showing the IF power state control table for the GMPLS control unit  30   c  in step  611 ; 
           [0044]      FIG. 34  is a drawing showing the switching state control table for the GMPLS control unit  30   c  in step  612 ; 
           [0045]      FIG. 35  is a drawing showing the IF power state control table for the GMPLS control unit  30   a  in step  613 ; 
           [0046]      FIG. 36  is a drawing showing the switching state control table for the GMPLS control unit  30   a  in step  614 ; 
           [0047]      FIG. 37  is a drawing showing the IF power state control table for the GMPLS control unit  30   d  in step  616 ; 
           [0048]      FIG. 38  is a drawing showing the switching state control table for the GMPLS control unit  30   d  in step  617 ; 
           [0049]      FIG. 39  is a drawing showing the IF power state control table for the GMPLS control unit  30   a  in step  619 ; 
           [0050]      FIG. 40  is a drawing showing the switching state control table for the GMPLS control unit  30   a  in step  620 ; 
           [0051]      FIG. 41  is a drawing showing the structure of the PATH message of  502 ; 
           [0052]      FIG. 42  is a drawing showing the structure of the PATH message of  509 ; 
           [0053]      FIG. 43  is a drawing showing the structure of the PATH message of  601 ; 
           [0054]      FIG. 44  is a drawing showing the structure of the PATH message of  615 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0055]    The embodiments of this invention are described next. 
       First Embodiment 
       [0056]    The network system of the first embodiment is shown in  FIG. 1 . 
         [0057]    The network system of this invention includes a one or more optical switch units  20 , one or more GMPLS control units  30 , a C-Plane network  40 , a D-Plane network  50 , and a network management equipment  80 . One or more LSP (Label Switched Paths)  60  are set on the D-Plane network  50 . In the figure and the description, a single optical switch unit  20  is paired with a single GMPLS unit  30  to form four sets; however, an optional number of these equipments can be set as required by the network. Moreover, the optical switch unit and the GMPLS control unit need not always be paired one to one, and a structure where one GMPLS control unit  30  controls multiple optical switching units  20  is also applicable to this invention. These optical switching units  20  and GMPLS control units  30  may be mounted in individual cases or may be mounted within the same case. 
         [0058]    When all the optical switching units  20  are joined by data lines allowing direct communication on the D-Plane network  50 , that state is called adjoining connections. Moreover, if the optical switching units controlled by the GMPLS control unit  30  are adjacently connected, then even if the GMPLS control unit itself is indirectly connected (by a router, etc.) for communication along the C-Plane network  40  and is not joined by a line allowing direct communication, a network structure made up of logical adjacent relations can be structured by utilizing for example tunneling technology. 
         [0059]    The present embodiment describes an example utilizing the optical wavelength switching capability as the switching performance. However, this invention can still be applied unchanged even in other switching units using other switching capabilities such as for packets or TDM defined for GMPLS. 
         [0060]    An optical switching unit  20  contains one or more optical interfaces  206 . The optical switching unit  20  switches data among these optical interfaces  206 . 
         [0061]    The GMPLS control unit  30  communicates via the C-Plane network  40  based on GMPLS protocols, sets, cancels and changes the LSP 60  status. Moreover, GMPLS control unit  30  conveys these settings to the optical switching unit  20  and commands changes in the actual switching state. 
         [0062]    The C-Plane network  40  is a packet network using an IP protocol. 
         [0063]    The D-Plane network  50  is a set of lines (data lines) joining interfaces for the optical switching unit  20 . 
         [0064]    The LSP 60  is a logical path joining one or more data lines on the D-Plane network  50  and defined as a path from an interface to another interface. Two LSP are specified in  FIG. 1 . One LSP is the LSP 60   a,  which is an LSP via the IF-2 of optical switching unit  20   a  and the IF-1 of optical switching unit  20   d  forming a path from the IF-1 of optical switching unit  20   a  to IF-2 of optical switching unit  20   d.  The other LSP is the LSP 60   b  which is an LSP via the IF-1 and IF-2 of optical switching unit  20   b  from IF-3 of optical switching unit  20   a,  IF-1 and IF-2 of optical switching unit  20   c,  and IF-4 of optical switching unit  20   d.    
         [0065]    The components of optical switching unit  20  are shown in  FIG. 2 . 
         [0066]    The optical switching unit  20  includes a CPU 201 , a memory  202 , a secondary storage device  203 , a communication interface  204 , a switch  205 , and an optical interface  206 . The embodiment of this invention can be implemented if the switching unit contains one communication interface  204  but utilizing one or more communication interfaces  204  does not present a problem. 
         [0067]      FIG. 3  shows sub-components of the optical interface unit  206 . 
         [0068]    An optical interface unit  206  includes an internal interface unit  2061 , a signal processing unit  2062 , an O/E converter unit  2063 , and E/O converter unit  2064 , and a power supply controlling unit  2065 . 
         [0069]      FIG. 4  shows components the GMPLS control unit  30 . The GMPLS control unit  30  is made up of the CPU 301 , a memory  302 , a secondary storage device  203 , and one or more communication interfaces  204 . 
         [0070]    The data structure required to implement this invention is described next. 
         [0071]      FIG. 7  is a drawing showing the data structure of the PATH message. The PATH message  700  contains an RSVP message type  701 , and one or more RSVP objects that are parameters of PATH message  700 . The RSVP object includes the required objects such as the session identifier  702 , an RSVP hop  703 , a refresh period  704 , and optional objects. Optional objects include the protection object  705 , the service type  706 , and the allowable recovery time  707 . Other objects are objects  708 ,  709 . 
         [0072]    The protection object  705  is specified by RFC3473 and the draft-ietf-ccamp-gmpls-recovery-e2e-signaling-04.txt. The protection object  705  includes a flag showing where the path is the main path or the spare path, and a flag showing whether the spare path is in the operating state or non-operating state. 
         [0073]    The service type  706  is an object showing the type of service used on the main path. When a path setting is initiated by signaling from outside this network system, the service type  706  indicates that a service is utilizing the main path. 
         [0074]    The allowable recovery time  707  is a parameter showing the upper limit for the time required to shift the spare path from a non-operating state to an operating state. 
         [0075]    A description of the RESV message is omitted since this invention does not introduce new parameters. 
         [0076]      FIG. 8  is a diagram of the data structure of the network topology table; 
         [0077]    The network topology table  800  is stored in the memory  302  of the GMPLS control unit  30 , and holds the D-Plane network  50  topology information. 
         [0078]    The network topology table  800  includes fields for the endpoint A node ID 8001 , endpoint A IF_ID 8002 , endpoint B node ID 8003 , endpoint B IF_ID 8004 , switching capability  8005 , and the link attribute  8006 . 
         [0079]    The endpoint A node ID 8001 , endpoint A IF_ID 8002 , endpoint B node ID 8003  and endpoint B IF_ID 8004  are respectively identifiers showing both endpoints of the respective lines. The endpoint A and endpoint B sides do not indicate a particular order or sequence. The endpoint A node ID 8001  and the endpoint B node ID 8003  are ID for showing the GMPLS control unit  30  for regulating the respective applicable optical switching units  20 . The endpoint A node ID 8001  and the endpoint B node ID 8003  generally utilize an IP address of GMPLS control unit  30 . The endpoint A IF_ID 8002  and endpoint B IF_ID 8004  are each ID numbers for identifying the corresponding optical interface unit  206 . 
         [0080]    The switching capability  8005  indicates the switching capability for each line for the packet, TDM and optical wavelength. 
         [0081]    The link attribute  8006  is a field showing one or more line attributes such as the line speed and transmission delay time. 
         [0082]      FIG. 9  is a data structure table for the power control capability table. 
         [0083]    The power control capability table  900  is in the memory  302  of GMPLS control unit  30 , and contains the fields for node ID 9001 , IF_ID 9002 , power control states  9003 , power states  9004   a - 9004   c.    
         [0084]    The node ID 9001  and IF_ID 9002  are utilized for identifying the target interfaces. The contents of node ID 9001  are identical to endpoint A node ID 8001 . The contents of IF_ID 9002  are identical to the endpoint A IF_ID 8002 . 
         [0085]    The power control states  9003  value indicates the power control states used for the applicable interface. If this value is zero it indicates that power is constantly applied and there is no power control capability for the applicable interface. 
         [0086]    The power state  9004  is present as  9004   a,    9004   b  . . . according to the value in the power control states  9003 , and shows the power-saving rate in each power state and time for recovery to the normal state. 
         [0087]    In this embodiment, the power state is ST 0  if power is constantly supplied without power control (or power regulation); the power state is ST 1  if the power is off just for the internal interface unit  2061  within optical interface unit  206 ; the power state is ST 2  if the power for the signal processing unit  2062  and the internal interface unit  2061  are off; the power state is ST 3  if the power to the O/E converter unit  2063  and the E/O converter unit  2064  is off in addition to the signal processing unit  2062  and the internal interface unit  2061 . 
         [0088]    The data making up the network topology table  800  and the power control capability table  900  might be changed autonomously within each of the GMPLS control units  30  by using a routing protocol, or might be set in the GMPLS control unit  30  by a management equipment outside this system. The present invention can be implemented in either of these cases. 
         [0089]      FIG. 13  is a drawing showing the structure of the service type recovery time control table; 
         [0090]    The service type recovery time control table  1300  is inside the memory  302  of GMPLS control unit  30  and contains the respective fields for the service type field  1301  and the allowable recovery time field  1302 . 
         [0091]    The service type field  1301  is stored as a value matching the service type  706  of PATH message  700 . The allowable recovery time field  1302  is stored as a value for the recovery time allowed for the applicable service type. 
         [0092]    Typical service types include dedicated lines, VoIP, general Internet, high-quality Internet, etc. Examples of the allowable recovery time for these services are shown in the figure. The figure is only an example and this invention is not limited to the values in the figure. 
         [0093]    The service type recovery time control table  1300  value is set based on the operating policy of the administrator of this network system. How this value is determined is beyond the applicable scope of this invention. 
         [0094]      FIG. 10  is a drawing showing a switching state control table. 
         [0095]    A switching state control table  220  is stored in the memory  202  of the optical switching unit  20 , and controls the state of the switching unit  205 . 
         [0096]    The switching state control table  220  contains respective fields for an input IF field  2201 , an output IF field  2202 , and an IF state field  2203 . 
         [0097]    The input IF field  2201  contains IF number for the input side of switch  205 . The output IF field  2202  contains IF numbers for the output side of the switch  205 . The IF state field  2203  contains the IF state specified by the input IF field  2201 . 
         [0098]    The IF states are respectively: Not used; In-use; Reserved; and Problem. Here, Not Used indicates that the IF is not being utilized; In-use indicates that the IF is connected to the output IF; Reserved indicates a path has already been set via that IF to serve for example as an auxiliary path during fault recovery but actually is in a state where not connected by the switch  205  to the input IF and output IF. Also, Problem (or fault) indicates that a fault has occurred in the input IF, and data communications cannot be performed. 
         [0099]    The output IF field  2202  value is not used and its value is ignored if in a state where the IF state field  2203  value is not in use. 
         [0100]      FIG. 11  is a drawing showing the IF power status control table. 
         [0101]    The memory  202  of optical switching unit  20  contains the IF power state control table  230 . The IF power state control table  230  controls the power state of the optical interface unit  206 . 
         [0102]    The IF power state control table  230  contains respective fields for an IF_ID field  2301  and an IF power state field  2302 . 
         [0103]    An ID for the optical interface  206  serving as the object is stored in IF_ID field  2301 ; and the power state for the applicable interface is stored in the If power state field  2302 . The value for the IF power state field  2302  is specified in the power state  9004  of power control capability table  900 . 
         [0104]      FIG. 12  is a drawing showing the data structure of the path state control table  330 . 
         [0105]    The path state control table  330  is data stored in the memory  302  of GMPLS control unit  30 ; and stores the path state that was set using the GMPLS protocol. 
         [0106]    The path state control table  330  contains respective fields for a session ID field  3301 , an input IF_ID field  3302 , and input label field  3303 , an output IF_ID filed  3304 , an output label field  3305 , a state field  3306 , an allowable recovery time field  3307 , another attribute value field  3308 . 
         [0107]    The session ID field  3301  stores session ID values utilized for identifying the path on the RSVP-TE protocol. 
         [0108]    The input IF_ID field  3302 , and input label field  3303 , an output IF_ID filed  3304 , an output label field  3305  respectively store the input side, and output side IF_ID values, and the label values. 
         [0109]    The IF_ID and labels are defined by the GMPLS protocol, and are for intended for abstract and unified handling of switches operated by various transmission methods. In this embodiment, the IF_ID is a numerical value for specifying the optical interface  206  of optical switch  20 , and the label is a numerical value for specifying the wavelength of the optical data input and output from the optical interface  206  of optical switch  20 . The IF_ID and the label values are numerical values. Each GMPLS control unit  30  sets these independently and notifies the connecting GMPLS control units  30  of these values. The IF_ID and the label values are not related to any physical values. (for example, figures expressing the optical wavelength in nanometers, etc.) and only for making decisions on whether values are a match (size of the value is not significant). 
         [0110]    In the RSVP-TE, the GMPLS control unit decides the IF_ID value for controlling that interface, and the label value is determined by the downstream side or in other words, the side accepting the data so that the input IF_ID field  3302 , and input label field  3303 , an output IF_ID field  3304  determine and store their own values; and the value in the output label field  3305  was a value stored after notification from another adjacent connecting downstream GMPLS control unit. 
         [0111]    The state field  3306  stores each path state. These path states include the “Operating” and the “Reserved” states. 
         [0112]    The path is set in each GMPLS control unit  30  per that operating state. Moreover, even in the optical switching unit  20  the switch  205  is set to the state matching that path setting. During the reserved state on the other hand, that path is set in each GMPLS control unit  30  but the switch  205  of optical switching unit  20  is not yet set to a state. 
         [0113]    The allowable recovery time field  3307  stores the value notified by the allowable recovery time  707  of PATH message  700 . 
         [0114]    The other attribute value field  3308  stores the various types of path information defined by the RSVP-TE. The handling of the other field values is the same as the handling specified in RSVP-TE. There is no need to make a change in the embodiment of this invention so a detailed description is omitted. 
         [0115]    A summary of the fault recovery procedure for a D-Plane line fault in the network of  FIG. 1  is described next. This embodiment assumes that data communication is implemented on data input from IF-1 of optical switching unit  20   a  and output from IF-2 of optical switching unit  20   d.    
         [0116]    The fault recovery methods include a method for searching for a substitute path after a fault occurs and setting the path; and a method for reserving a substitute path in advance, and making a quick recovery by switching the path state after a fault occurs from the reserved state to the operating state. The example in this embodiment employs the latter method that sets a substitute path in advance. Therefore in  FIG. 1  two paths are set. One path is LSP 60   a,  which is set as the main path, and the other is LSP 60   b,  which is the spare path. The data usually flows on the LSP 60   a  path, and when a fault occurs on the data line for LSP 60   a,  the switching is changed in each optical switching unit  20  to switch the data communication to the LSP 60   b,  which is the spare path. 
         [0117]      FIG. 5  is a sequence diagram showing the process for setting the spare path and the main path in the first embodiment. The event assumed to initiate the path setting process may be multiple causes such as path setting instructions from a network processor equipment and signaling from an outside network and this invention can be implemented by any of these causes. In the example of this embodiment, the path setting is initiated by instructions from the network management equipment  80 . 
         [0118]    The GMPLS signaling protocols include multiple protocols such as RSVP-TE and CR-LDP. The present invention can be implemented no matter which of these protocols are employed. The RSVP-TE protocol is utilized as the signaling protocol in the example of this embodiment. 
         [0119]    When setting the main path which is LSP 60   a,  first of all, the network management equipment  80  commands the GMPLS control unit  30   a  controlling the optical switching path unit  20   a  serving as the path start point, to calculate the main path in  501 , and select a path to the optical switching unit  20   d  as the path endpoint by way of IF-1 of optical switching unit  20   d,  and IF-2 of optical switching unit  20   a  serving as the directly connected link. 
         [0120]    Next, the GMPLS control unit  30   a  sends a path message  502  serving as an RSVP-TE message requesting establishment of a path, to the GMPLS control unit  30   d  controlling the optical switching unit  20   d  serving as the connecting node and also as the path endpoint node. 
         [0121]      FIG. 41  is a drawing showing the structure of the PATH message of  502 . 
         [0122]    After accepting the path message  502 , the GMPLS control unit  30   d  confirms that the requested path can be set, sets the path requested to optical switching unit  20   d  in  502 ,  503 , and sends an RESV message  505  which is an RSVP-TE message showing a response to the path set request check to the GMPLS control unit  30   a.    
         [0123]      FIG. 17  is a drawing showing the IF power state control table for the GMPLS control unit  30   d  to be set in step  503 .  FIG. 18  is a drawing showing the switching state control table for the GMPLS control unit  30   d  to be set in step  504 . 
         [0124]    When the RESV message  505  is received, the GMPLS control unit  30   a  sets the main path in the optical switching unit  20   a  in  506 ,  507  to complete the setting of the LSP 60   a.    
         [0125]      FIG. 19  is a drawing showing the IF power state control table for the GMPLS control unit  30   a  to be set in step  506 .  FIG. 20  is a drawing showing the switching state control table for the GMPLS control unit  30   a  to be set in step  507 . 
         [0126]    The process sequence for setting the spare path LSP 60   b  is shown next. The redundant processing method used during path setting such as setting the spare path is specified as a parameter when starting to set the main path and is therefore outside the scope of the present invention. 
         [0127]    The GMPLS control unit  30   a  calculates the spare path in  504 . This spare path is a path using nodes different from the main path. The GMPLS control unit  30   a  selects a path to the optical switching unit  20   d  via the optical switching units  20   b,  and optical switching units  20   c  as the spare path. The optical switching unit  20   a  and the optical switching units  20   d  here are the respective start point and endpoint which is common to both the main path and the spare path but the main path and spare path respectively utilize different interfaces so that redundancy is acquired on the interface level. 
         [0128]    The spare path calculation is made based not merely on topology information between the optical switches as described later on but also by taking the power saving capability of interfaces having optical switches into account. 
         [0129]      FIG. 42  is a drawing showing the structure of the PATH message of  509 . 
         [0130]    After calculating the path, the GMPLS control unit  30   a  sends a PATH message  509  to the GMPLS control unit  30   b  controlling the optical switching unit  20   b  serving as the next connecting node. At this time, a parameter (parameter already specified by RSVP-TE) showing that the path is a spare path and currently in the non-operating state is added to the PATH message  509 , and a PATH message containing an allowable recovery time as a parameter showing the maximum value for recovery time required for switching the spare path from a non-operating state to an operating state is sent. In the current example, the service type  706  value is High Quality Internet, and the allowable recovery time  707  is 5 seconds. 
         [0131]    After confirming that the specified path can be set, the GMPLS control unit  30   b  sends a PATH message  510  to the GMPLS control unit  30   c  controlling the optical switching unit  20   c  serving as the next connecting node. This PATH message  510  also includes the allowable recovery time as a parameter, the same as PATH message  509 . 
         [0132]    Similarly, after the GMPLS control unit  30   c  confirms that the specified path setting is possible, it sends a PATH message  511  to the GMPLS control unit  30   d  controlling the optical switching unit  20   d  service as the next connecting mode and also as the endpoint node. This PATH message  511  also includes the allowable recovery time as a parameter, the same as PATH message  509 . 
         [0133]    When the GMPLS control unit  30   d  that controls the optical switching unit  20   d  serving as the endpoint node confirms that setting the requested path is possible, it sets the interface power control state used in the spare system in  512  to the state with the highest power-saving rate within the allowable recovery period indicated in PATH message  511 , by making switch settings in  513 . The joint recovery time in the current example is 5 seconds so ST 2  is set as the power state. 
         [0134]      FIG. 21  is a drawing showing the IF power state control table for the GMPLS control unit  30   d  to be set in step  512 .  FIG. 22  is a drawing showing the switching state control table for the GMPLS control unit  30   d  to be set in step  513 ; 
         [0135]    The RESV message  514  is in this way sent to the GMPLS control unit  30   c  and notification sent that path setting is complete. 
         [0136]    The GMPLS control unit  30   c  sets the power state of the spare interface in the same way in  515 , sets the switch state in  516 , and sends the RESV message  517  to the GMPLS control unit  30   b.    
         [0137]      FIG. 23  is a drawing showing the IF power state control table for the GMPLS control unit  30   c  to be set in step  515 .  FIG. 24  is a drawing showing the switching state control table for the GMPLS control unit  30   c  to be set in step  516 ; 
         [0138]    The GMPLS control unit  30   b  next sets the power state of the spare interface in  518 , sets the switch state in  519 , and sends the RESV message  520  to the GMPLS control unit  30   a.    
         [0139]      FIG. 25  is a drawing showing the IF power state control table for the GMPLS control unit  30   b  to be set in step  518 . FIG.  26  is a drawing showing the switching state control table for the GMPLS control unit  30   b  to be set in step  519 . 
         [0140]    The GMPLS control unit  30   a  sets the power state of the spare interface in  521 , and sets the switch state in  522  to complete the setting of the spare LSP 60   b.    
         [0141]      FIG. 27  is a drawing showing the IF power state control table for the GMPLS control unit  30   a  to be set in step  521 .  FIG. 28  is a drawing showing the switching state control table for the GMPLS control unit  30   a  to be set in step  522 . 
         [0142]      FIG. 6  is a process sequence diagram showing the changing of spare LSP 60   b  from a non-operating state to an operating state, and changing the main path LSP 60   a  to a non-operating state. 
         [0143]    The process for switching a redundant system utilizing GMPLS is carried out by switching to the spare system by the GMPLS control unit serving as the path start point, sending a PATH message containing the path state change. The method for reporting an abnormality on the main path to the path start point GMPLS control unit is beyond the scope of the GMPLS method and is also outside the scope of this invention which is not dependent on a specific method. The example of the embodiment, shows the case where the process for switching over to the redundant system starts by the optical switching unit  20   a  sending a switchover request for the spare system path to the GMPLS control unit  30   a.    
         [0144]    The GMPLS control unit  30   a  sends a PATH message  601  containing a parameter showing that the path state has been changed from (spare system, non-operating) state to a (spare system, operating) state to the GMPLS control unit  30   b.  Hereafter, the GMPLS control unit  30   b  sends the PATH message  602  to the GMPLS control unit  30   c,  and the GMPLS control unit  30   c  sends the PATH message  603  to the GMPLS control unit  30   d  in the same sequence as when setting the path; and completes the changing of the LSP 60  from a non-operating state to an operating state by sending the RESV message  604 , RESV message  605 , RESV message  606  in the reverse direction. In this case, the GMPLS control units  30   d - 30   a  set the respective IF power control states to SO 0  in  607 ,  609 ,  611 , and  613 , and sets the switching unit  205  state in  608 ,  610 ,  612 , and  614 , And sets the spare LSP 60   b  to the operating state to allow the flow of data. 
         [0145]      FIG. 29  is a drawing showing the IF power state control table for the GMPLS control unit  30   d  to be set in step  607 .  FIG. 30  is a drawing showing the switching state control table for the GMPLS control unit  30   d  to be set in step  608 .  FIG. 31  is a drawing showing the IF power state control table for the GMPLS control unit  30   c  to be set in step  609 .  FIG. 32  is a drawing showing the switching state control table for the GMPLS control unit  30   c  to be set in step  610 .  FIG. 33  is a drawing showing the IF power state control table for the GMPLS control unit  30   c  to be set in step  611 .  FIG. 34  is a drawing showing the switching state control table for the GMPLS control unit  30   c  to be set in step  612 .  FIG. 35  is a drawing showing the IF power state control table for the GMPLS control unit  30   a  to be set in step  613 .  FIG. 36  is a drawing showing the switching state control table for the GMPLS control unit  30   a  to be set in step  614 .  FIG. 43  is a drawing showing the structure of the PATH message of  601 . 
         [0146]    Next, the GMPLS control unit  30   a  sends a PATH message  615  containing a parameter showing that the path state has been changed from (main system, operating) state to a (main system, non-operating) state to the GMPLS control unit  30   d.  The GMPLS control unit  30   d  sets the power control state of the IF in  616 , sets the switching unit  205  state in  617 , and sends the RESV message  618  to the. GMPLS control unit  30   a.  The GMPLS control unit  30   a  changes the main path to the non-operating state by setting the power control state of the IF in  619 , sets the state of the switching unit  205  in  620 . 
         [0147]      FIG. 37  is a drawing showing the IF power state control table for the GMPLS control unit  30   d  to be set in step  616 .  FIG. 38  is a drawing showing the switching state control table for the GMPLS control unit  30   d  to be set in step  617 .  FIG. 39  is a drawing showing the IF power state control table for the GMPLS control unit  30   a  to be set in step  619 .  FIG. 40  is a drawing showing the switching state control table for the GMPLS control unit  30   a  to be set in step  620 .  FIG. 44  is a drawing showing the structure of the PATH message of  615 . 
         [0148]    When setting the IF state in  607 ,  609 ,  611 , and  613 , the alarm showing a communication error from the applicable IF during the allowable recovery period that is reported during path setting is masked, and the warning (alarm) information is temporarily suppressed. Suppressing the alarm in this way separates the alarm that unavoidably occurs during the transition period from a non-operating to an operating state, from an actual equipment alarm, and serves to reduce the load on the administrator. 
         [0149]      FIG. 14  is a flow chart showing path calculation process  3500 . 
         [0150]    The path calculation process  3500  is a program executed by the CPU 301  of the GMPLS control unit  30 . 
         [0151]    The path calculation process  3500  is executed via  501  and  508  of  FIG. 5 . 
         [0152]    In the path calculation process  3500  whether to make the spare path calculation is first of all decided in step  3501 . Whether or not to calculate the spare path is decided by the value in the protection object  705  in PATH message  700 . 
         [0153]    In the case of the main path, the process proceeds to step  3502 , the network topology table  800  values are checked, and an appropriate path is selected. 
         [0154]    If the path is the spare path then the process proceeds to step  3503 , the value of the service type  706  of PATH message  700 , and the value of the service type recovery time control table  1300  are checked and the value of the allowable recovery time then found. 
         [0155]    Next, in step  3504 , path information for the main path (previously defined as the RSVP-TE object) and the allowable recovery time are set as limiting conditions, the network topology table  800  and power control capability table  900  are checked, and the path calculated with the condition that the path is the maximum power saving path. The algorithm used for calculating the path under specified limiting conditions, is a well known as GMPLS protocol such as shown for example in RFC2702 and therefore a detailed description is omitted here. 
         [0156]      FIG. 15  is a flow chart of the IF state setting process  3600  during the path setting. 
         [0157]    The IF state setting process  3600  during path setting is a program executed by the CPU 301  of the GMPLS control unit  30 . 
         [0158]    The IF state setting process  3600  during path setting is executed in  512 ,  515 ,  518 , and  521  in  FIG. 5 . 
         [0159]    In the IF state setting process  3600  during the path setting a decision is first made on whether the path set in step  3601  is the spare path or not. The decision conditions are the same as in step  3501 . 
         [0160]    If the path that was set was not the spare path, then no particular power control of the interface is being carried out so the process terminates. 
         [0161]    If the spare path was set in step  3601  then the process proceeds to step  3602 , the path state control table  330  is checked, and a check made to find whether the allowable recovery time was set for the path. If the allowable recovery time was not set then the process terminates unchanged. 
         [0162]    If the allowable recovery time was set, then the path state control table  330  is checked in step  3603 , and a check made on whether another spare path has already been set in the IF that must be set. If another path has been set then a minimum value is found from among the allowable setting times that were set in that IF, and that value is then newly set as the allowable setting time in step  3604 . 
         [0163]    Then in step  3605 , the power control capability table  900  is checked, and the power state with the highest power-saving rate is found from among the power states satisfying the specified recovery time that was set, and that value is rewritten into the IF power state control table  230  by sending an instruction to the optical switching unit  20 . 
         [0164]    The communication protocol used here between the GMPLS control unit  30  and the optical switching unit  20  is outside the applicable range of GMPLS and is a vendor-specific protocol. In many cases, the TL/1 protocol is utilized as this optical switching unit control protocol but other protocols are also applicable to the implementation of this invention. 
         [0165]      FIG. 16  is a flow chart of the IF state setting process  3700  during changing of the path state. 
         [0166]    The IF state setting process  3700  during path state changing is a program executed by the CPU 301  of GMPLS control unit  30 . 
         [0167]    The IF state setting process  3700  during path state changing is implemented by  607 ,  609 ,  611 ,  613 ,  616 , and  619  of  FIG. 6 . 
         [0168]    In step  3701  of IF state setting process  3700  during path state changing, a decision is made whether to change the state to the operating state, and if a change to the operating state, then the process proceeds to step  3702 . If not a change to the operating state, then the process proceeds to step  3704 . In step  3702  the values in the allowable recovery time field  3307  of path state control table  330  are searched, and an instruction sent to the optical switching unit  20  to mask the interface warning (alarm) information when changing the state within the time that was set. 
         [0169]    Then in step  3703 , the optical switching unit  20  is instructed to set the power control state of the applicable interface to the normal state. 
         [0170]    If not changing to the operating state, then in step  3704  the optical switching unit  20  is instructed to set the power control state of the applicable interface to a state where power consumption is small. 
         [0171]    The above process is capable of reducing power consumption of the spare path. 
         [0172]    This invention is effective on network systems where control is implemented by way of GMPLS protocols. This invention is particularly effective for reducing the power consumption on the redundant path.