JP5132586B2 - Communication device and network interface card - Google Patents

Description

  The present invention relates to a communication device that transmits information via a network, and in particular, a communication device and a network interface card that use IPv6 as a communication protocol and have a function of putting the components of the device into a dormant state to reduce power consumption. About.

  Various power-saving technologies have been tried to reduce power consumption in communication devices that exchange information via a network. Many of these attempts are to put a component of a device such as a processor in a sleep state during standby.

  However, if the communication device is completely put into a dormant state, it becomes impossible to respond to a protocol that requires a steady response, or the expiration date of information acquired from another communication device or the external environment is appropriate. There are problems such as being unable to manage.

  As a method of suppressing power consumption while solving this problem, Patent Documents 1 and 2 compare the means for storing received frames and whether or not the received frames match a specific frame without going through the processing of the processor. And a communication device that transmits a frame stored in advance as a response when the two coincide with each other.

  On the other hand, Patent Documents 3 and 4 each include a communication device that includes two processors with different power consumption, performs protocol processing with a processor with low power consumption during standby, and activates the main processor when a predetermined packet arrives. It is disclosed.

JP-A-9-160882 Japanese Patent No. 3906890 JP 2006-259906 A JP 2006-279821 A

  However, in the prior arts listed in Patent Literature 1 and Patent Literature 2, the communication device can continuously indicate the presence of the own device to the outside, but the state of the own device cannot be appropriately updated. Therefore, appropriate management of information and status obtained from other communication devices and the external environment cannot be realized. On the other hand, the prior arts listed in Patent Document 3 and Patent Document 4 can check the existence of the device itself and appropriately manage information and status. However, absolute power consumption cannot be reduced because the sub processor continues communication processing.

  In addition, assuming a communication device that actively uses the hibernation state for the purpose of reducing power consumption, if the device is not specially devised, the hardware related to the network every time it returns from the hibernation state Or initialize the software. For example, many existing personal computers use this method. Although this method can reliably resume the network connection, there is an overhead associated with initialization. This is not preferable not only in terms of time but also in terms of power consumption. For example, when a packet is transmitted / received along with reacquisition of information, it is necessary to perform each process such as packet generation / transmission / reception standby / reception / analysis / information update. If this communication device is supposed to be operated in a power-poor environment such as a solar battery, battery consumption in such information re-acquisition processing should be avoided.

  Therefore, the present invention provides a communication device that can significantly reduce the power consumption of the device itself by reliably obtaining the minimum information necessary for communication even in a dormant state and suppressing the operation time required for information transmission. The purpose is to do.

A communication apparatus according to an aspect of the present invention is a communication apparatus that transmits information via a network, and that controls a main operation, constructs a frame to be transmitted via the network, and software that operates on the processor A main memory for storing data used by the network, a network interface connected to the network, a frame extraction unit for extracting a specific frame from a frame received by the network interface, and a frame extracted by the frame extraction unit, An information extraction unit that extracts information necessary for transmitting information via the network, a storage unit that stores information extracted by the information extraction unit, and the processor transmits information to the network At the time of the processor by the processor. With respect to the frame that is built on Nmemori, it rewrites the specific information using the information stored in the storage unit, anda information replacing unit for sending to the network interface, the network interface, the frame The extraction unit, the information extraction unit, and the storage unit operate independently of operating states of the processor and the main memory .

  According to the present invention, there is provided a communication device capable of significantly reducing the power consumption of the device itself by reliably obtaining the minimum information necessary for communication even in a dormant state and suppressing the operation time required for information transmission. Can be provided.

The block diagram which shows the structure of the communication apparatus which concerns on 1st embodiment of this invention. The figure which shows the range where electric power is supplied at the time of suspension Diagram showing the operation sequence during suspend Diagram showing normal operation sequence Network configuration diagram for use in Ethernet (registered trademark) / IPv6 network The figure which shows the information preservation | save state in the memory | storage part 106 Figure showing a typical example of router advertisement The block diagram which shows the structure of the communication apparatus which concerns on 2nd embodiment of this invention. The figure which shows the operation | movement sequence at the time of the frame transmission which concerns on 2nd embodiment. The block diagram which shows the structure of the communication apparatus which concerns on 3rd embodiment (expansion of 1st embodiment) of this invention. The block diagram which shows the structure of the communication apparatus which concerns on 3rd embodiment (expansion of 2nd embodiment) of this invention. The figure which shows the sequence regarding the timer setting / starting which concerns on 3rd embodiment (expansion of 1st embodiment) of this invention. The block diagram which shows the structure of the communication apparatus which concerns on 4th embodiment (expansion of 1st embodiment) of this invention. The block diagram which shows the structure of the communication apparatus which concerns on 4th embodiment (expansion of 2nd embodiment) of this invention. The figure which shows the sequence regarding the timer setting / starting which concerns on 4th embodiment (expansion of 1st embodiment) of this invention. Diagram showing an example of the frame to be generated

<First embodiment>
Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of a communication apparatus according to the present invention. Reference numeral 100 denotes the communication apparatus, 101 denotes a processor in which main software of the communication apparatus operates, and 102 denotes a main memory in which main software and data of the communication apparatus are stored. Reference numeral 103 denotes an information replacement unit that rewrites a destination link layer address (MAC address), a transmission source network layer address, and the like with respect to information to be transmitted to the network, and reference numeral 104 denotes a frame received from the network, even in a dormant state in the communication apparatus. A frame extraction unit that extracts a specific frame that needs processing, and 105 is an information extraction unit that extracts information that needs processing from the frame extracted by the frame extraction unit 104. Reference numeral 106 denotes a memory for storing information extracted by the information extraction unit 105, and reference numeral 107 denotes a network I / F that connects the apparatus to a network.

  FIG. 1 omits portions other than those directly related to the present invention. For example, when this communication device functions as a sensor node that transmits information via a network, a sensor unit may be provided, or when a permanent and large-capacity storage unit is required, a disk device may be provided. . Moreover, although it is necessary to provide the power supply part which can operate only one part according to an operation state on the structure of this apparatus, it is abbreviate | omitting in FIG.

  The communication device described in the present embodiment has two operation states of “operation state” and “rest state”. When in the “operating state”, in principle, all elements constituting the communication apparatus are in an energized state, and their functions can be used. In the “hibernation state”, power supply to some elements is stopped and only limited functions are available. FIG. 2 shows a portion for supplying power when the communication apparatus of the present invention is in a dormant state. In the rest state, power is supplied to the units 104, 105, 106, and 107 within the dotted frame in FIG.

  First, in the first embodiment, a series of processes executed when the communication apparatus is in a dormant state will be described. Subsequently, a series of processing executed when the communication apparatus is in an operating state will be described. By combining the two, the entire operation of the communication apparatus is shown.

[First Embodiment / Sleep Sequence]
FIG. 3 shows an operation sequence when the communication apparatus of the present invention is in a dormant state. As shown in FIG. 2, even when this apparatus is in a dormant state, the network I / F 107 is energized and can receive frames from the network (step S301). Thereafter, the received frame is sent to the frame extraction unit 104 (step S302). The frame extraction unit 104 checks whether or not the received frame is a frame of interest (a frame that needs to be processed even when the apparatus is in a pause state, hereinafter referred to as “frame of interest”) (step S303). At this time, if the frame notified in step S302 is not the frame of interest, the process ends after this step (not shown in FIG. 3). Subsequently, another frame is received via the network I / F 107 (step S304), and the frame extraction unit 104 (steps S305 and S306) determines. As a result of the determination, it is assumed that the frame is a target frame. In this case, the frame extraction unit 104 notifies the information extraction unit 105 of the frame (step S307).

  When receiving the target frame, the information extraction unit 105 extracts information from a predetermined area in the frame (step S308). Then, the information extraction unit 105 stores the extracted information in the storage unit 106. The above is the operation when the communication apparatus is in a dormant state. In this way, the communication apparatus determines whether the packet received via the network I / F 107 is a frame to be processed, and if it is to be processed, extracts necessary information from the frame. Then, the process of saving it in the memory is repeatedly executed. Note that frames other than the frame of interest are stored in the main memory 102 and processed by the processor 101 when the processor 101 is operating.

[First embodiment / sequence of operation states]
FIG. 4 is an operation sequence when the communication apparatus of the present invention is in an operating state. When this apparatus is in an operating state, in principle, an operation of transmitting information to the outside via a network is performed. When a notable frame is received via the network, the processing based on FIG. 3 described above is executed in the same manner, but is omitted here.

  First, a frame including information to be transmitted to the network by the processor 101 is created (step S401) and stored in the main memory 102 (step S402). When the storage is completed, the processor 101 executes transmission processing for transmission to the network (step S403). In the present embodiment, the transmission process is a pre-process necessary for transmitting a frame via the information replacement unit 103 and the network I / F 107. In the transmission process, the processor 101 notifies the information replacement unit 103 of the main memory area in which the frame is stored (step S404). Receiving this notification, the information replacement unit 103 reads a frame from the area (steps S405 and S406). Further, the information replacement unit 103 reads information necessary for rewriting the frame area from the storage unit 106 (steps S407 and S408). Thereafter, the information read from the storage unit 106 is used to rewrite a predetermined area of the frame read from the main memory 101 (step S409). When the rewriting is completed, the information replacing unit 103 notifies the network I / F 107 of the rewritten frame (step S410), and the network I / F 107 transmits the frame to the network (step S411). The above is the flow of processing for transmitting a frame when the communication apparatus of the present invention is in an operating state.

  Here, a supplementary description will be given of the processing (step S401) when the processor 101 creates the frame to be transmitted. As described with reference to FIG. 3, the communication apparatus receives various information from the network and other nodes when it is in a dormant state, and stores it in the storage unit 106. This information includes information on the link layer address of the node that is the next hop and the network layer address that can be used by the communication device itself. However, as shown in FIG. 4, the contents of the storage unit 106 are not referred to when creating a frame with this communication apparatus. In this communication apparatus, the frame is rewritten to a frame having correct information by the information replacement unit 103 immediately before transmission. For this reason, when the processor 101 creates a frame (step S401), the frame is created using dummy information. Since this dummy information is rewritten by the information replacement unit 103, any value may be used. However, malfunctions can be prevented by using addresses reserved by the protocol used. In addition, since the area to be rewritten by the information replacement unit is fixed, there is no need to worry about the same information appearing in the frame to be rewritten.

  The above is the operation of the communication apparatus shown in the first embodiment. In this communication device, information necessary for transmission is collected in advance while it is in the dormant state, stored in the storage unit 106, and immediately after moving to the operation state, a frame including desired transmission information is created. Can be sent. As a result, the period of the operating state is shortened. Thereby, reduction of power consumption in the whole node can be expected.

<First embodiment / specific example using IPv6>
Next, a specific description will be given by taking as an example the case where the communication apparatus according to the first embodiment is used in a network using Ethernet and IPv6. FIG. 5 shows a configuration diagram of a network to which the communication apparatus is connected. In this figure, the router 501 and the communication device 502 are connected via a network 500 configured by Ethernet. Although FIG. 5 includes one router and an end node, other nodes may be connected.

[Hibernate Sequence]
The router 501 periodically transmits router advertisement (Router Advertisement) to the network 500 in accordance with the IPv6 specification. In general, an IPv6 prefix used in the network 500 is stored in the router advertisement. An IPv6 node connected to the network 500 obtains an IPv6 prefix from a router advertisement, generates an IPv6 address to be used by itself by stateless address automatic setting, and learns a MAC address of a default router. In view of this specification, the frame focused on by the communication apparatus is an Ethernet frame that carries a router advertisement. Processing after the router 501 transmits a router advertisement to the network 500 and reaches the network I / F 107 of the present apparatus will be described according to the operation sequence described in FIG.

  The router advertisement arriving at the network I / F 107 (step S304) is delivered to the frame extraction unit 104 (step S305). The frame extraction unit 104 confirms that the notified frame is a router advertisement (step S306).

  Here, the frame extraction unit 104 that confirms that the input frame is an IPv6 router advertisement can be easily realized. In general, since the position of a field necessary for determination is fixed, the header structure is not analyzed and a specific area may be read statically and determined using the value. More specifically, the type field of the Ethernet header is IPv6 (0x86DD), the next header field of the IPv6 header is ICMPv6 (58), the type field of the ICMPv6 header is 134, and the code is 0. Check each one. However, in a network where the administrator makes special settings, the field position may change due to the insertion of a VLAN tag or an IPv6 option header. In order to cope with such a situation, the reference destination may be easily changed.

  When the confirmation by the frame extraction unit 104 is completed, the frame extraction unit 104 notifies the information extraction unit 105 of a frame including the IPv6 router advertisement (step S307). The information extraction unit 105 that has received the notification of the frame from the frame extraction unit 104 regards the received frame as an IPv6 router advertisement, and extracts the MAC address and prefix information of the transmission source router (step S308). Information to be extracted includes the MAC address and IPv6 address of the router that transmitted the router advertisement, the lifetime of the router, the IPv6 prefix, the prefix length, the validity period of the prefix, and the recommended period. The MAC address of the router may be extracted from the source address of the Ethernet header, or may be extracted from the corresponding field of the source link layer address option (ICMPv6 option type number 1). Information about the prefix is extracted from the prefix information option (ICMPv6 option type number 3). These options can appear in any order within an ICMPv6 packet and can be used redundantly. Therefore, if it is determined that the packet is an ICMPv6 packet, it is assumed that the processing content of the option area ahead can be determined based on the type field. The information extraction unit 105 may be mounted so as to perform various inspections required by the IPv6 specification. For example, confirmation of ICMPv6 checksum can be cited as an example of inspection. When a series of information can be extracted, the information extraction unit 105 notifies the storage unit 106 of the information (step S309) and stores it (step S310).

  FIG. 6 shows how various types of information are stored in the storage unit 106.

  Reference numeral 601 denotes a column that stores the MAC address of the router extracted by the above-described method. Reference numeral 602 denotes a column that stores an IPv6 address that is a source address of the router advertisement. Reference numeral 603 denotes a lifetime (Router) notified by the router advertisement. Lifetime).

  Reference numeral 604 is a column for storing the IPv6 prefix notified by the prefix information option included in the router advertisement and the prefix length for the prefix, and 605 is a valid period (Valid) for the IPv6 prefix notified by the prefix information option included in the router advertisement. 606 is a column for storing a recommended period (Preferred Lifetime) for the IPv6 prefix notified by the prefix information option included in the router advertisement. Reference numeral 607 denotes a column for storing the time when the entry is stored.

  In the example of FIG. 6, one router advertisement including one prefix information is received, and various information included therein is entered. There may be a case where a plurality of prefixes are included for one router advertisement. In such a case, all prefixes may be saved, or only one prefix may be saved. The method to select one is the one that appears first, the one that appears last, the one that has confirmed reachability to the target communication partner, the one based on the priority determined at the time of design or operation, etc. It may be determined by the method. Whichever method is selected, it is a matter of design and does not limit the embodiment of the present invention.

  When a plurality of prefixes are stored, it is necessary to select an appropriate prefix at the time of transmission. This process is based on a standard procedure defined in IPv6.

  In this figure, it is stored in the form of a table, but the format is a design item and does not limit the embodiment of the present invention. Further, although the IPv6 prefix and the prefix length are described in the same entry, they may be recorded separately. When the information extraction unit 105 stores information in the storage unit 106, it may be stored after confirming that the stored information can be used for information transmission from the communication apparatus. For example, if the lifetime of the router notified by the received router advertisement is zero, the router cannot be used as a default router. In that case, information as a router (MAC address or IPv6 address) may not be stored. Similarly, if the prefix validity period or recommended period is zero, these prefixes cannot be used and need not be saved. On the other hand, the extracted information may be stored as it is by confirming when the above-described restriction is used.

  FIG. 7 shows a typical example of a router advertisement transmitted by the router 501 and received by the communication apparatus 502. The field described by the underline in the figure is information to be confirmed and extracted by the frame extraction unit 104 and the information extraction unit 105 of the communication apparatus as described above. The series of processes described so far are processes executed regardless of the operating state of the processor 101 as described above. In the IPv6 network, a router advertisement is received and a prefix is known, and its own IPv6 address is generated based on the received router advertisement. However, in this communication apparatus, information regarding the prefix can be appropriately collected even when the processor 101 is in a dormant state.

[Operation status sequence]
Next, processing when the processor 101 enters an operating state and attempts to transmit data from the communication apparatus will be described in detail based on the processing sequence of FIG. 4 using an IPv6 network as an example. In this description, it is described as processing executed after a series of processing described in the previous description on the receiving side.

  First, the processor 101 assembles an Ethernet frame including information to be transmitted (step S401). At this time, as described in the dormant process, a frame is created using a dummy IPv6 prefix set in advance and the MAC address of the router. The created frame having the dummy address is stored in the main memory 102 (step S402). Thereafter, the processor 101 performs transmission processing with the dummy address as it is (step S403).

  After the transmission process, the processor 101 notifies the information replacement unit 103 of information on the area where the frame is stored (step S404). Receiving this notification, the information replacement unit 103 reads the area (steps S405 and S406).

  Thereafter, information stored in the storage unit 106 is read in order to correctly update the areas in which the dummy addresses are entered and areas (for example, checksums) depending on these addresses (steps S407 and S408). The information to be read at this time requires at least three of the router's MAC address, the IPv6 prefix used as the source address, and the prefix length. Other information is a design item that depends on the stored information and design. In addition, when a plurality of prefixes are recorded in the entry stored in the storage unit 106, an appropriate prefix may be selected and read before reading, or an appropriate prefix may be read after reading all. Alternatively, one may be selected.

  The read MAC address replaces the destination MAC address of the transmission target frame, and the read IPv6 prefix and the IPv6 prefix generated from the prefix length replace a part of the source address of the IPv6 header. At this time, it is not necessary to replace the portion corresponding to the interface ID of the IPv6 address.

  Basically, an area in a frame to be replaced by a series of replacement processes is determined in advance. Therefore, the information replacement unit 106 can be implemented with a simple configuration. However, in order to realize higher adaptability, for example, replacement for a frame with a VLAN tag may be supported.

  Whether or not the read information can be used properly on the network regardless of whether or not it is “implemented to determine whether a router or prefix can be used at the time of transmission” described in the description of the operation in the dormant state. Need to do. Specifically, the validity period of the router or prefix must be confirmed. As shown in FIG. 6, each entry has a storage time. Confirm that the current time is within the storage time plus the lifetime. If a valid MAC address, IPv6 prefix, and prefix length do not exist, the frame transmission process results in an error and the frame is discarded.

  The information replacement unit 106 notifies the network I / F 107 of the frame whose address has been rewritten (step S410), and is sent to the communication partner via it (step S411).

  FIG. 16 shows an example of an Ethernet frame generated when the communication apparatus transmits data generated in a node using IPv6 and UDP in the form of an Ethernet frame.

  1601 is an Ethernet header, 1602 is an IPv6 header, 1603 is a UDP header, and 1604 is data. Of the fields shown in FIG. 16B, two types of shaded areas will be described. The first area (cross-shaded area; two locations of 1601 “Destination MAC Address” field and 1602 “Source Address” field) stores dummy values uniquely determined by the communication apparatus of the present invention. It is.

  The second area (left diagonally shaded area; “Checksum” field 1603) is a value that depends on the first area, and the storage checksum is a value calculated including the IPv6 address stored in the IPv6 header. In this apparatus, since a frame is generated using a dummy address for IPv6 Source Address, the UDP checksum also has a dummy value.

  The dummy information here is information that is originally notified or available from the connection environment such as another node on the connected network, but is not known in this communication device. Nevertheless, this information is temporarily used in the processing when a situation necessary for the processing occurs. For example, IPv6 Source Address is required to generate an IPv6 packet. However, since the router advertisement is not received immediately after the node is activated, the exact IPv6 address is not known (except when it is set statically). In order to generate an IPv6 packet in a state where this address is unknown, dummy information is used as “IPv6 Source Address”. At this time, the dummy information has an IPv6 address form. Similarly, Destination MAC Address can be described.

  In the communication apparatus of the present invention, the dummy value is rewritten to regular information by the information replacing unit 103. Therefore, there is no need to worry about the contents of the information. Depending on the implementation, it may be a specific bit string determined at the time of design, or may be dynamically generated using a random number.

  The above is a specific example when the transmission processing of this communication apparatus is applied to an IPv6 network. In this communication apparatus, the software operating on the processor 101 does not need to know the MAC address or IPv6 prefix of a router that can be normally used on the network. For this reason, it is not necessary to re-acquire network information immediately after the processor 101 returns from the sleep state to the operation state. As a result, a frame including information can be created immediately and sent to the network. As a result, operations such as obtaining an address from a router and assigning an interface, which are necessary for a normal IPv6 node, are unnecessary, and power consumption can be reduced.

<Second Embodiment>
In the first embodiment, the present invention has been described as an example in which the present invention is implemented by a communication device. FIG. 8 is a block diagram when configured as a network interface card. In addition, the same number is attached | subjected about the element which has the same function as 1st embodiment, and description is abbreviate | omitted.

  Reference numeral 800 denotes a communication device to which a network interface card 802 that implements the present invention is attached. Reference numeral 802 denotes a network interface card that implements the present invention. Reference numeral 801 denotes a processor 101, a main memory 102, and a network interface card 802. A bus to be connected.

  The network interface card 802 is further composed of several elements. A control unit 803 controls the network interface card 802 and connects to the bus 801. A buffer 804 temporarily stores frames in various processes performed on the network interface card 802. It is memory. Note that the control unit 803 and its operation are not the essence of the present invention. Other control mechanisms such as a register and a DMA controller may be used.

  Similar to the first embodiment, also in this embodiment, the network interface card takes two states, a sleep state and an operation state. In the dormant state, only the network I / F 107, the frame extraction unit 104, the information extraction unit 105, and the storage unit 106 operate. On the other hand, when in the operating state, all the components operate.

  The network interface card 802 may transition between the two states in relation to the operation state of the communication device 800, or may transition independently. However, when the present network interface card 802 is in a dormant state, the communication device 800 cannot transmit a packet. The operation sequence in the dormant state in the present embodiment is the same as the operation sequence in the dormant state in the first embodiment, and thus description thereof is omitted.

  FIG. 9 shows a sequence when a frame is transmitted in the operating state. Since most of them are the same as those in the first embodiment, different sequences will be described in a supplemental manner.

  When the processor 101 transmits information to the network, the control unit 803 requests transmission in step S904. At this time, the main memory address storing the frame is also notified.

  The control unit 803 reads the frame from the main memory 102 using the address notified from the processor 101 (step S905), and stores it in the buffer memory 804 of the network interface 802 (step S906). When the storage in the buffer memory 804 is completed, the control unit 803 issues an information rewrite request to the information replacement unit 103 (step S907). In this rewrite request, the address of the frame stored in the buffer memory 804 is passed.

  The operation of the information replacement unit 803 when executing rewriting is the same as that in the first embodiment (steps S908 to S910).

  When the rewriting is completed, the information replacing unit 103 notifies the control unit 803 that the rewriting has been completed (step S911). Receiving this completion notification, the control unit 803 issues a transmission request for the frame to the network I / F 107 (step S912). At this time, the address on the buffer memory 804 is also notified. The network I / F 107 reads the frame from the buffer memory 804 based on the notified address information (steps S913 and S914), and transmits it to the network (step S915). Here, the configuration in which the control unit 803 issues a transmission request to the network I / F 107 based on the completion notification from the information replacement unit 103 has been described, but the information replacement unit 103 directly issues a transmission request to the network I / F 107. You may comprise as follows.

  In addition to the effect expected in the first embodiment, the effect expected in the present embodiment is that the implementation of the present invention is independent as the network interface card 802, so that it can be applied to an existing communication device. It can be easily applied. In this case, if the dummy information such as the IPv6 address and the default router MAC address is set in advance for the software operating on the communication device, the transmission frame can be generated immediately. It is possible to suppress the time of the operation state.

<Third embodiment>
Next, a third embodiment will be described. This embodiment is an improvement over the first or second embodiment. In this embodiment, in addition to all the two embodiments, further reduction of power consumption is attempted. More specifically, a time management by a timer is introduced instead of continuously supplying power to the portion in the dormant state. It is intended to save more power by supplying power in accordance with the timing at which the information stored inside needs to be updated.

  Block diagrams of the present embodiment are shown in FIGS. FIG. 10 is an extension of the first embodiment, and FIG. 11 is an extension of the second embodiment. Both figures are different in that a timer activation unit 1001 (1101) is newly added.

  The timer activation unit 1001 (1101) added in the present embodiment has a function for specifying the time to wait from the outside, a function for turning on the power supply unit after the designated time has elapsed, and a power on. It has the function of turning off after a certain period of time.

  The timer starting unit 1001 (1101) manages the power sources of elements in the dotted frame in each figure. Other parts are managed as before. The state where the power is turned off by the timer activation unit 1001 (1101) is a state where only a smaller number of elements are energized than in the conventional hibernation state (in this embodiment, only the timer activation unit is energized). ) Hereinafter, this state is referred to as a “quasi-stop state”. 10 and 11, the power supply controller that goes from the timer activation unit 1001 (1101) to each component is omitted. The timer activation unit 1001 (1101) is connected to the information extraction unit 105, and refers to all or part of the extracted information. In general, an effective period is provided for information notified via a network. In this embodiment, a timer is set using these values stored together with information in the packet of interest. For example, in the case of a network using IPv6, the smallest one of the router lifetime, prefix validity period, and prefix recommendation period extracted by the information extraction unit 105 may be selected. Note that the value actually set in the timer is slightly smaller than the extracted value. By doing so, it is possible to avoid invalidating the stored information. As a result, the quasi-stop state is maintained while the advertised information is valid, and the timer activation unit 1001 (1101) pauses (in the first and second embodiments) when the information becomes invalid. It can be used to transition to a state.

  Further, in setting the timer, the operation of the application executed on the apparatus may be taken into consideration. For example, when an application that periodically transmits information is included, the smallest period may be selected in consideration of the information transmission interval of the application. Information on the application is transmitted from the processor 101 to the timer activation unit 1001 (1101) (in FIGS. 10 and 11, the connection between the processor 101 and the timer activation unit 1001 (1101) is not shown).

  FIG. 12 shows an operation sequence of the present embodiment. However, since it is almost the same as the sequence diagram in the first and second embodiments, only the part related to the timer is shown in a supplemental form. Further, the sequence diagram of FIG. 12 is indicated by a thick frame when the power of the element is ON. In addition to the operations shown in FIG. 3 so far, steps S1201 to S1205 are added. The information extracted by the information extraction unit 105 is notified to the storage unit 106 and is also notified to the timer activation unit 1001 (1101) (step S1201). The timer starting unit 1001 (1101) sets a value that is considered appropriate from the notified information to the timer (step S1202). As described above, the appropriate determination is made based on the rule of the shortest (slightly shorter value) of the router lifetime, the prefix validity period, and the recommended prefix period in the case of a network using IPv6. This rule is determined in advance for the timer activation unit 1001 (1101). However, this is a design matter, and the rules may be defined flexibly. When the timer setting is completed, the timer activation unit 1001 (1101) controls the power supply unit and turns off the power supply of each unit in the apparatus (step S1207). This state is a semi-stop state. Thereafter, the timer activation unit 1001 (1101) waits in a form that does not affect the outside until the set timer expires.

  When the timer activation unit 1001 (1101) confirms that its timer has expired (step S1208), the timer activation unit 1001 (1101) controls the power supply unit to turn on the power of each unit in the apparatus (step S1209). Thereby, it returns from a semi-stop state to a dormant state.

  Note that, when the power of the storage unit 106 is turned off, it is necessary to change the correspondence method depending on the memory elements constituting the storage unit 106. For example, when a volatile memory such as a DRAM is used, it is necessary to use a backup by a battery or to keep an energized state like the timer starter. On the other hand, when a non-volatile memory such as a flash memory, MRAM, or FeRAM is used, backup is unnecessary and the power can be turned off. As described above, in the present embodiment, the timer is set based on the time information associated with the information to be extracted, and the semi-stop state is entered. And it returns to a dormant state when the timer expires. Thereby, it is possible to turn off the power of more elements than in the first and second embodiments. In the meantime, since information necessary for transmission is kept within the expiration date, it is possible to obtain an effect of shortening the time in the operation state by promptly executing the transmission processing. Therefore, power consumption can be further reduced.

<Fourth embodiment>
A fourth embodiment obtained by further expanding the third embodiment will be described. In the present embodiment, the time of the timer set in the timer activation unit is determined based on the interval at which the frame of interest is received, thereby reducing the power consumption compared to the first or second embodiment. .

  Block diagrams in this embodiment are shown in FIGS. 13 and 14, respectively. FIG. 13 is derived from the first embodiment, and FIG. 14 is derived from the second embodiment.

  In FIG. 13 and FIG. 14, an interval detector 1301 (1401) is added. The interval detection unit 1301 (1401) has a function of accepting that the frame extraction unit 104 has extracted the frame of interest, a function of detecting the intervals when the extraction is received a plurality of times, and a detected interval. It has a function of notifying the timer starter 1001 (1101). Thus, when a node in the network uses a protocol that periodically notifies information, a timer is set based on an interval for receiving the notification.

  For example, when the present apparatus is used in a network using IPv6, the frame extraction unit 104 extracts an IPv6 router advertisement. Since the IPv6 router advertisement is periodically transmitted from the router, the frame extraction unit 104 also periodically extracts the router advertisement. Further, when notifying the extracted router advertisement to the information extracting unit 105, the interval detecting unit 1301 (1401) recognizes that the router advertisement has been extracted. When this notification is performed a plurality of times, an interval from the previous notification is detected.

  In addition, by notifying the timer activation unit 1001 (1101) of the interval detected by the detection interval unit 1301 (1401), the timing of transition from the semi-suspended state to the dormant state of this apparatus and the interval for receiving the IPv6 router advertisement Can be synchronized. FIG. 15 shows an operation sequence of the present embodiment. However, since they are almost the same as the sequence diagrams in the first and second embodiments, only the portions related to the interval detection unit 1301 and the timer activation unit 1001 are shown in a supplemental form. Further, the sequence diagram of FIG. 15 is indicated by a thick frame when the power of the element is ON.

  First, the received frame is notified from the network I / F to the frame detection unit 104 (step S305). In response to this, the frame detection unit 104 determines whether or not the frame is a notable frame (step S306). If it is not a notable frame, the process ends here (not shown).

  If the frame is notable, the information extraction unit 105 is notified of the received frame (step S307). At this time, the interval detection unit 1401 detects the signal to be notified and recognizes that it has been received (step S1501). In the operation of step S1501, the received frame notification itself is recognized, but a dedicated notification may be sent.

  The interval detection unit 1401 that has found that the frame of interest has been received calculates the difference between the time detected last time and the time detected this time (step S1502), and notifies the timer activation unit 1001 of the difference (step S1503). If it is detected for the first time, notification to the timer activation unit 1001 is not performed, and the process ends after step S1502. As for the detected time, only the latest detection time is stored in the interval detection unit 1401.

  Subsequent operations are the same as those in the third embodiment, and are therefore omitted.

  In the third and fourth embodiments, the timer activation unit 1001 (1101) is used only when a frame to be noticed can be received in a certain period after the transition from the semi-stop state to the dormant state by the timer activation unit 1001 (1101). 1101) again turns off the power supply of each unit and causes the communication apparatus 100 or the network interface card 802 to transition to the semi-stop state.

  If it cannot be detected that the corresponding frame has been received (step S1201 in FIG. 12 and step S1503 in FIG. 15 is not executed), it may wait until it is detected. As a result, it is possible to prevent information from being missed due to a shift in activation timing. As described above, in the present embodiment, the timer is set based on the reception interval of the frame of interest and the semi-stop state is entered. And it returns to a dormant state when the timer expires. Thereby, it is possible to turn off the power of more elements than in the first and second embodiments. In the meantime, since information necessary for transmission is kept within the expiration date, it is possible to obtain an effect of shortening the time in the operation state by promptly executing the transmission processing. Therefore, power consumption can be further reduced. In addition, since more frames of interest are received than in the third embodiment, more stable information maintenance can be expected.

<Transition from quasi-stop state / pause state triggered by transmission processing>
A communication apparatus or network interface card that implements the present invention transitions from a semi-stop state or a stop state to an operation state by transmission processing led by the processor 101. This is executed, for example, when the interrupt signal managed by the processor 101 is activated. In order to realize this, the communication device or the network interface card that implements the present invention has a mechanism capable of controlling the power supply unit from the processor 101 or the control unit 803 (not illustrated in the series of descriptions). In the third or fourth embodiment, the power supply unit may be controlled from the processor 101 or the control unit 803 and may be controlled from the timer activation unit 1001 (1101). An appropriate exclusive control mechanism and an operation state management mechanism (such as a register for storing the current operation state) are required to prevent inconsistencies between them (all omitted in the figure).

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

100 ... communication device,
101... Processor
102 ... main memory,
103 ... Information replacement part,
104 ... frame extraction unit,
105. Information extraction unit,
106 ... storage part,
107 ... Network I / F

Claims (10)

A communication device that transmits information via a network,
A processor that controls the main operation and constructs a frame to be transmitted through the network;
A main memory for storing data used by software operating on the processor;
A network interface connected to the network;
A frame extraction unit for extracting a specific frame from a frame received by the network interface;
An information extraction unit that extracts information necessary for transmitting information from the frame extracted by the frame extraction unit via the network;
A storage unit for storing the information extracted by the information extraction unit;
When the processor sends information to the network, the frame constructed on the main memory by the processor is rewritten with specific information using information stored in the storage unit, and An information replacement unit to be sent to the network interface ,
The communication apparatus , wherein the network interface, the frame extraction unit, the information extraction unit, and the storage unit operate independently of operating states of the processor and the main memory . When generating information to be transmitted by the processor on the main memory, a frame is created using information set in advance regardless of a network connected via the network interface, and the information replacement unit The communication apparatus according to claim 1 , wherein the communication apparatus transmits the information after rewriting the information according to a network to be connected. The frame extracted by the frame extraction unit is an IPv6 router advertisement, and the information extracted by the information extraction unit is at least an IPv6 prefix included in the router advertisement and a router MAC address. Item 3. The communication device according to Item 2 . It is composed of a processor that controls the main operation and constructs a frame to be transmitted via a network, a main memory that stores data used by software that operates on the processor, and a bus that connects the main memory and the processor, A network interface card used to connect to the bus for a communication device that transmits information via a network,
A control unit connected to the bus;
A buffer memory for temporarily storing information to be exchanged with the main memory via the control unit;
A network interface connected to the network;
A frame extraction unit for extracting a specific frame from a frame received by the network interface;
An information extraction unit that extracts information necessary for the communication device to transmit information via the network from the frame extracted by the frame extraction unit;
A storage unit for storing the information extracted by the information extraction unit;
An information replacement unit that rewrites specific information using information stored in the storage unit for frames stored for transmission in the buffer memory;
And a network interface card that operates independently of an operating state of a connected communication device . The network interface, the frame extraction unit, the information extraction unit, and the storage unit, when the processor is in a dormant state, the power is turned off accordingly,
An effective period is set based on the information extracted by the information extraction unit, and power is supplied to the network interface, the frame extraction unit, the information extraction unit, and the storage unit when the effective period expires communication apparatus according to claim 1, characterized by further comprising a timer activation unit that instructs the. The network interface, the frame extraction unit, the information extraction unit, and the storage unit, when the communication device connected to the network interface card is in a dormant state, the power is turned off accordingly,
An effective period is set based on the information extracted by the information extraction unit, and power is supplied to the network interface, the frame extraction unit, the information extraction unit, and the storage unit when the effective period expires 5. The network interface card according to claim 4 , further comprising a timer starting unit for instructing to. Further comprising an interval detection unit for detecting timing for extracting a specific frame by the frame extraction unit;
The communication apparatus according to claim 5, wherein the effective period is set using an interval detected by the interval detection unit. Further comprising an interval detection unit for detecting timing for extracting a specific frame by the frame extraction unit;
The network interface card according to claim 6, wherein the valid period is set using an interval detected by the interval detection unit. The communication apparatus according to claim 1 or 5 or 7 wherein the storage unit is characterized by being composed of a nonvolatile memory. Network interface card according to claim 4 or 6 or 8 wherein the storage unit is characterized by being composed of a nonvolatile memory.

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