JP2007228292A - Station side apparatus, subscriber side apparatus, and pon system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a station side apparatus for efficiently performing data communications with holding the privacy of information on a PON (passive optical network) system. <P>SOLUTION: The OLT 1 comprises an MLD/IGMP filter 13 for snooping control messages of the multicast communication; a multicasting encrypt key generator 21 for generating a multicasting encrypt key, based on the snoop result of the control messages; an encrypter 14 for encrypting multicast frames for a multicast group by giving information concerning the encrypt, after selecting a multicast encrypt key corresponding to a multicast identifier of the multicast group, based on information for relating to the multicast identifier of a subscriber terminal; and a PON-IF 10 for sending the multicast frames encrypted by the encrypter 14 by broadcasting to the subscriber apparatus. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a station-side device, a subscriber-side device, and a PON system that perform data communication via an optical transmission medium.

  In recent years, development of a PON (Passive Optical Network) system for connecting a station-side device and a subscriber-side device using an optical transmission medium has been advanced. For example, E-PON, which is a PON system using Ethernet (registered trademark), uses an optical line terminal (OLT) as a station side device and a plurality of ONUs (Optional Network Units) as subscriber side devices as optical transmission media. Data is transmitted and received through a MAC (Media Access Control) frame. Here, the OLT is installed in the communication network operator station, and the ONU is installed in the subscriber's home or outdoors and accommodates one or more subscriber terminals. Thereby, in E-PON, the Ethernet (registered trademark) service is transparently accommodated in the PON system.

  There are the following two methods for transmitting a multicast frame in the PON system. That is, in the first method (MCB (Multiple Copy Broadcast) method), the OLT that has received the multicast frame from the upper network copies the data for the destination of the multicast frame and sends it to the PON section. For example, when two registered ONUs are connected to the OLT, the OLT copies two pieces of data and sends them to the PON section. If N ONUs (N is a natural number) are registered in the multicast group, the OLT copies N data and sends it to the PON section.

  In the second method (SCB (Single Copy Broadcast) method), an OLT that has received a multicast frame from an upper network adds information indicating that it is multicast transmission to the data as an ONU-ID, and puts the multicast data in the PON section. Send it out. At this time, the OLT does not copy the data and sends only one type of frame.

  In such PON system multicast communication, it is desired to communicate efficiently while maintaining the confidentiality of information. In other words, in the multicast communication of the PON system, it is necessary to ensure security without wasting bandwidth.

  However, in the case of the first multicast frame transmission method described above, data is copied and transmitted as many times as the number of ONUs registered in the multicast group, so that there is a problem that the bandwidth of the PON section is wasted. It was.

  On the other hand, in the case of the second multicast frame transmission method described above, the OLT does not copy data and sends only one type of frame, so that the bandwidth of the PON section is not wasted. However, since this method of transmitting a transmission frame in a broadcast manner distributes the frame to other than a specific ONU, the transmission frame leaks to a subscriber terminal under the ONU, and the confidentiality cannot be maintained. there were.

  For example, Non-Patent Document 1 defines an encryption function and an implementation method in an E-PON system. In this Non-Patent Document 1, in the Secure Data field in which fields other than the destination address DA (Destination Address) and the source address SA (Source Address) of the MAC frame are encrypted, a SecTAG (Secure TAG) field indicating encryption information and By adding an ICV (Integrity Check Value) field indicating authentication information, security communication is enabled.

  The VoIP communication system described in Patent Document 1 is a VoIP communication system in which a plurality of terminal devices and gateways are connected via a LAN. The gateway combines data such as voice packets to the plurality of terminal devices into one. The packets are sent to the LAN by multicast or broadcast as packets that can be received by a plurality of terminal devices. Each terminal device extracts data addressed to itself from packets receivable by the plurality of terminal devices received from the LAN.

  The terminal device described in Patent Document 2 includes a multicast encryption key table storage unit that stores a stream number, a multicast condition, a target termination device identifier, and a multicast encryption key, and the received transmission frame matches the multicast condition. In this case, the header is set to broadcast communication, the corresponding stream number is set to the header, and the transmission frame is encrypted with the corresponding multicast encryption key. The terminating device also includes a multicast encryption key table storage for storing a stream number and a multicast encryption key. The header of the received transmission frame is broadcast communication, and the stream number set in the header is the multicast encryption key. When it exists in the key table storage unit, the transmission frame is decrypted with the corresponding multicast encryption key.

IEEE P802.1 AE / D4.0 Media Access Control (MAC) Security JP 2002-124949 A JP 2005-197947 A

  However, the first prior art has a problem that multicast communication cannot perform efficient communication that does not waste bandwidth while maintaining confidentiality of information.

  Further, the second prior art has a problem that the confidentiality of data to be transmitted cannot be maintained because the multicast packet and the broadcast packet are not encrypted.

  In the third prior art, since the transmission frame to be transmitted is multicast-transmitted, the configuration of the data communication apparatus becomes complicated, and the data communication is performed while maintaining the confidentiality of the data with a simple configuration. There was a problem that could not.

  The present invention has been made in view of the above, and an object of the present invention is to obtain a station-side device, a subscriber-side device, and a PON system that efficiently perform data communication while maintaining the confidentiality of information on the PON system. To do.

  In order to solve the above-described problems and achieve the object, the present invention is connected to a subscriber side apparatus accommodating one or more subscriber terminals via an optical transmission medium on a PON system and to an IP network. A snoop unit that snoops a control message used for control of multicast communication in a station side device that transmits and receives data to and from the subscriber side device using a predetermined data frame on the optical transmission medium; and Multicast related to association of encryption key generation unit for generating multicast encryption key based on snoop result, multicast encryption key generated by encryption key generation unit, and multicast identifier for identifying multicast group of subscriber terminal Based on the management table, it corresponds to the multicast identifier of the multicast group. An encryption unit that selects an encryption key for multicasting, encrypts the multicast frame to the multicast group by adding information related to encryption, and broadcasts the multicast frame encrypted by the encryption unit. And a transmission unit for transmitting to.

  According to the present invention, since the multicast frame is encrypted with the multicast encryption key corresponding to the multicast group and transmitted to the subscriber side device by broadcast, the data is efficiently stored while maintaining the confidentiality of the data frame on the PON system. There is an effect that communication can be performed.

  Embodiments of a station side device, a subscriber side device, and a PON system according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

  Before describing the embodiments of the present invention, a Gigabit E-PON (E Passive Optical Network) system (GE-PON) based on EFM (Ethernet (registered trademark) in the First Mile) to which the present invention is applied will be described. .

  In the GE-PON system, a bridge function is implemented in the OLT, and a logical port is applied as a bridge port. A general bridge performs switching in units of physical ports, but when performing communication between ONUs in a PON system that shares a single transmission path with a plurality of ONUs, it is necessary to make the bridge aware of the ports for each ONU. . Further, when the ONU accommodates a plurality of user interfaces (hereinafter referred to as UNI (User Network Interface)), it is necessary to make the bridge aware of the port for each UNI in order to perform communication between the UNIs of the ONU. Such a port for each ONU or UNI is called a logical port. A logical port exists in the OLT and the ONU, and a network connecting the logical ports is called a logical link.

  The logical link is identified by LLID (Logical Link Identifier) which is a unique identifier in the PON. The LLID is selected by the OLT and notified to the ONU. The LLID is defined in the preamble of the MAC frame and has a 16-bit configuration. This value is defined as 1 for all broadcast preambles.

Embodiment 1 FIG.
FIG. 1 is a diagram illustrating a configuration of a PON system according to a first embodiment of the present invention. The PON system 100 includes one OLT 1 that is a station side device (single station device) and a plurality of ONUs 2 that are subscriber side devices (terminating devices) connected to the OLT 1 via an optical transmission medium. One to a plurality of subscriber terminals 5 are connected to each ONU 2. Here, a case where there are three ONUs 2 in the PON system 100 and one subscriber terminal 5 is connected to each ONU 2 is shown as an example of the PON system 100.

  The OLT 1 is connected to the data distribution server 3 via the switch 4 in the IP network 101. Here, a case where there is one OLT 1 connected to the IP network 101 will be described, but a plurality of OLTs 1 connected to the IP network 101 may be provided.

  When the subscriber terminal 5 forms a group, the OLT 1 and the ONU 2 can use, for example, a multicast message protocol MLD (Multicast Listner Discovery), an IGMP (Internet Group Multicast Protocol) report message, a leave message, and an SNI as multicast IP protocols. MLD and IGMP Query messages from the data distribution server 3 via (Service Node Interface) are snooped to manage information about multicast groups (multicast group information). In addition, data on the PON system 100 (between OLT 1 and ONU 2) is transmitted after being encrypted for security. The Report message, Leave message, MLD, and IGMP Query message here correspond to the control message described in the claims.

  For example, when unicast transmission is performed from OLT 1 to ONU 2, data D 1 to D 3 are transmitted from OLT 1 to the PON side. Each data D1 to D3 is transferred from the ONU 2 corresponding to the destination of each data to the subscriber terminal 5.

  Here, a frame format transmitted in the PON system 100 will be described. FIG. 2 is a diagram illustrating an example of a frame format transmitted in the PON system. In FIG. 2, the DA field 60, SA field 61, and User Data field 64 shown on the upper side are the data before encryption, and the DA field 60, SA field 61, SecTAG field 64, Secure Data field, shown on the lower side, The ICV field 63 is data after encryption.

  The frame format (after encryption) transmitted in the PON system 100 includes an encrypted MAC frame format according to IEEE P802.1AE. The encrypted MAC frame format includes a MAC frame having a SecTAG (Secure TAG) field 62 indicating encryption information and an ICV (Integrity Check Value) field 63 indicating integrity check information. The unencrypted MAC frame format includes a destination address (DA) field 60, a source address (SA) field 61, and an MSDU (MAC Service Data Unit) field 64 indicating user data (User Data) information. It has.

  Among these, Secure Data, ICV63, SecTAG62, and ICV63 corresponding to MSDU (User Data64) constitute MPDU (MAC Protocol Data Unit). DA 60 and SA 61 constitute a MAC address.

  FIG. 3 is a diagram for explaining a detailed configuration of the SecTAG field. The SecTAG field 62 includes 2 bytes of ME (MAC Ether Type) 71 that is encryption tag type information, 1 byte of TCI / AN (TAG Control Information / Association Number) 72 that is encryption tag information, and SL that is information about the frame length. 1 byte of (Short Length) 73, 4 bytes of PN (Packet Number) 74 which is information on the number of packets, and 8 bytes of SCI (Secure Connectivity Identifier) 75 which is optional group identification information (multicast identifier). Yes. In the first embodiment, the SCI 75 is used as a group identifier, and the OLT 1 broadcasts a multicast frame to the ONU 2.

  One byte of TCI / AN72 (encryption tag information) is 1 bit of version information (V: Version), 1 bit of ES (End Station) information, 1 bit of SC (Secure Channel) information, broadcast (SCB: Single Copy) 1 bit of broadcast information, 1 bit of encryption information (E: Encrption), 1 bit of integrity check function (ICV: Integrity Check Value) information, and 2 bits of encryption key (AN: Association Network) information Has been. Here, SC is information indicating the presence / absence of SCI 75, which is a group identifier, and SCB is information indicating whether the frame is a broadcast frame.

  The SCI 75 is composed of system identification information (System Identifier) and port number (Port Number). The ICV field 63 is a field used for checking the integrity of the message. When GCM-AES (Galois Counter Mode Advanced Encryption Standard), which is an encryption algorithm of IEEE P802.1AE, is used, the ICV value corresponds to a checksum of 8 bytes to 16 bytes. The range of the integrity check can be applied to the MSDU field of the user data information (User Data) 64.

  Next, a protocol stack of the E-PON system (PON system 100) according to the first embodiment will be described. FIG. 4 is a diagram for explaining the protocol stack of the PON system. FIG. 4 shows an OSI (Open System Interconnection) reference model and a protocol stack for performing encryption in the E-PON system.

  The OLT 1 and ONU 2 of the E-PON system (PON system 100) are communication devices that handle data below the data link layer of the OSI reference model. In the protocol stack, an LLC (Logical Link Control) layer 80, an MPCP (Multi-Point) Control Protocol or MAC Control) layer 81, MAC layer 83, RS (Reconciliation Sublayer) layer 84, PCS (Physical Coding Sublayer) layer 85, PMA (Physical Medium Attachment) layer 86, PMD (Physical Medium Dependent Sublayer) layer 87 To do. The encryption layer 82 in the first embodiment is located immediately below the MPCP layer.

  Referring to FIGS. 3 and 4, the SCI field (SCI 75) of the SecTAG field (SecTAG 62) is used to distinguish entities performing secure service / traffic discrimination. The SCI area (SCI 75) can also perform service / traffic discrimination for all ONUs 2. In the PON system 100, identification of multicast data and data encryption are performed in the same layer.

  Next, the configuration of the OLT 1 according to the first embodiment will be described. FIG. 5 is a block diagram of a configuration of the OLT according to the first embodiment. The OLT 1 is a station side device that realizes encrypted multicast communication, and connects to the IP network 101 and a PON interface (PON-IF) (transmitting unit) 10 that accommodates one or more ONUs 2 via a splitter. An SNI (Service Node Interface) 11 and a CPU (Central Processing Unit) (control unit) 12 are provided. Note that the functional configuration (functional division) shown in FIG. 5 is merely an example, and details of the PON-IF 10 and the SNI 11 are omitted.

  The PON-IF 10 includes an MLD / IGMP filter unit 13, an encryption unit 14, and a decryption unit 15. The MLD / IGMP filter unit (snoop unit) 13 snoops MLD and IGMP Report messages and Leave messages as a multicast IP protocol from the PON side (ONU 2), and MLD and data from the data distribution server 3 via the SNI 11 Snoop the IGMP Query message.

  The encryption unit 14 holds an encryption key, and encrypts data to be transmitted to the ONU 2 using this encryption key. The decryption unit 15 holds a decryption key, and decrypts data received from the ONU 2 using this decryption key.

  The SNI 11 includes a multicast monitoring unit 16 that monitors reception of multicast data from the data distribution server 3. Multicast data that the SNI 11 performs reception monitoring is input to the MLD / IGMP filter unit 13.

  The CPU 12 manages a multicast management table 17 that stores combinations of MAC address / multicast address / MLD, IGMP snoop result / encryption key (index) / ONU (LLID) / SCI. In addition, the CPU 12 includes a logical link control unit 18 that controls a logical link on the PON, and manages the LLID management table 19 that stores the usage status of the LLID value for each PON port by the logical link control unit 18. In the first embodiment, when an encryption key is distributed from the OLT 1 to the ONU 2, the logical link control unit 18 controls the logical link and sets a unicast path based on the LLID value stored in the LLID management table 19 . Then, multicast data from the OLT 1 to the ONU 2 is transmitted by broadcast using this unicast path.

  The CPU 12 also includes a multicast encryption key generation unit 21 and an MLD / IGMP monitoring unit 20 that monitors (snoops) MLD and IGMP messages. The CPU 12 includes means for controlling each function in the CPU 12, the PON-IF 10, and the SNI 11.

  The MLD / IGMP monitoring unit 20 reads information to be registered in the multicast management table 17 from various IGMPs snooped and extracted by the IGMP filter unit 13 and registers the information in the multicast management table 17.

  The multicast encryption key generation unit 21 is connected to the OLT 1 and generates a multicast encryption key based on the group identifier of the subscriber terminal 5 managed by the OLT 1. The multicast encryption key generation unit 21 generates a multicast encryption key when any of the subscriber terminals leaves. Further, the multicast encryption key generation unit 21 may generate and update a multicast encryption key at a predetermined cycle.

  Of the encryption keys stored in the multicast management table 17, the unicast encryption key is notified from the ONU 2, and is held and managed by the encryption unit 14 and the decryption unit 15 of the PON-IF 10.

  Of the encryption keys stored in the multicast management table 17, the multicast encryption key is generated by the multicast encryption key generation unit 21 based on the group identifier managed by the OLT 1, and the encryption unit 14 and the decryption unit 15 are generated. Maintain and manage in The multicast encryption key generated by the multicast encryption key generation unit 21 is encrypted by the encryption unit 14 based on the control of the CPU 11 and notified to the ONU 2. In the multicast management table 17, an encryption key index is stored.

  Here, the operation procedure of the OLT 1 will be described. First, an operation procedure when the OLT 1 receives data from the PON side (ONU 2) will be described. The OLT 1 receives the Report message transmitted from the subscriber terminal 5 (ONU 2) based on the MLD or IGMP Query message from the data distribution server 3 from the PON-IF 10, and receives the Report message in the MLD / IGMP filter unit 13. Snoop to capture. In this Report message, an IP group address used for multicast communication is stored.

  The MLD / IGMP monitoring unit 20 reads the Report message and the MLD / IGMP snoop result. The IGMP monitoring unit 20 here reads information indicating “Report” from the MLD / IGMP filter unit 13 as the MLD / IGMP snoop result. The MLD / IGMP monitoring unit 20 searches the multicast management table 17 using the IP group address in the Report message as a key.

  Here, the configuration of the multicast management table 17 provided in the OLT 1 will be described. FIG. 6 is a diagram illustrating an example of a configuration of a multicast management table provided in the OLT. The multicast management table 17 is for the LLID (P2P (peer to peer) (point to point) communication of the ONU 2 corresponding to the MAC address, the multicast address (IP group address), the MLD / IGMP snoop result, and the MAC address of the subscriber terminal 5. LLID), SCI corresponding to the multicast group, encryption key for performing P2P communication with ONU2, and encryption key for performing multicast communication (Multicast) with ONU2 .

  The multicast management table 17 is created using data (frames) transmitted and received between the ONU 2 and the data distribution server 3.

  For example, the multicast address of the subscriber terminal 5 whose MAC address is aa-aa-aa-aa-aa-aa, bb-bb-bb-bb-bb-bb, cc-cc-cc-cc-cc-cc is Xx. xx. xx. xx, indicating that the MLD / IGMP MLD / IGMP snoop results from the subscriber terminal 5 are “Report” (Report message), respectively.

  Also, the P2P LLID of the ONU 2 corresponding to the MAC address aa-aa-aa-aa-aa-aa is 1, the encryption key for P2P is # 1, and the MAC address is bb-bb-bb-bb-bb-bb The ONU2 P2P LLID corresponding to 2 is 2, the P2P encryption key is # 2, the ONU2 P2P LLID corresponding to the MAC address cc-cc-cc-cc-cc-cc is 3, and the P2P encryption key Is # 3.

  The multicast address xx. xx. xx. The SCI corresponding to xx is “00 00 00 00 00 01 00 01”, indicating that the multicast encryption key is #A. The encryption key managed here is an index (identification information), and the actual encryption key is managed by the encryption unit 14 of the PON-IF 10.

  As a result of the MLD / IGMP monitoring unit 20 searching the multicast management table 17, if an IP multicast address corresponding to (matching with) the IP group address is not found, the MLD / IGMP monitoring unit 20 transmits the report message. The person terminal 5 judges (recognizes) that it is the first group entry. Then, based on the Report message, the MLD / IGMP monitoring unit 20 adds the IP multicast address (IP group address), ONU (LLID), MLD / IGMP snoop result (Report), and usage to the unused entry in the multicast management table 17. The index of the encryption key to be stored is stored, and the SCI corresponding to the multicast group is stored. The ONU (LLID) here is preset in order to perform unicast communication between the OLT 1 and the ONU 2. The SCI is set in advance when setting a multicast group. Thereby, even if the subscriber terminal 5 is the first entry, encryption processing based on SCI, multicast frame transmission processing, and the like can be performed.

  Next, processing when an IP multicast address that matches an IP group address included in an MLD or IGMP Report message is found from an entry in the multicast management table 17 will be described.

  As a result of the MLD / IGMP monitoring unit 20 searching the multicast management table 17, when an IP multicast address corresponding to (matching with) the IP group address is found, the MLD / IGMP monitoring unit 20 transmits the report message. The terminal 5 determines (recognizes) that it is the second and subsequent group entry. Then, the MLD / IGMP monitoring unit 20 stores the MLD / IGMP snoop result (Report) and the new ONU (LLID) in the entry having the same IP multicast address in the multicast management table 17. As a result, even if the subscriber terminal 5 is in the second or subsequent entry, it is possible to perform encryption processing based on SCI, multicast frame transmission processing, and the like.

  Note that the unicast data from the ONU 2 received from the PON-IF 10 is decrypted with a decryption key corresponding to the unicast communication based on the contents of the multicast management table 17, and then the MLD / IGMP filter unit 13 performs MLD or The IGMP message is snooped and forwarded to the SNI 11. Note that the decryption in the first embodiment is performed using, for example, the same key (decryption key) as the encryption key.

  Next, an operation procedure when the OLT 1 receives data from the data distribution server 3 side will be described. Multicast data and unicast data transmitted by the data distribution server 3 are transmitted to the OLT 1 via the switch 4.

  When the OLT 1 receives the multicast data from the SNI 11, the OLT 1 inputs the multicast data to the MLD / IGMP filter unit 13. The CPU 12 causes the encryption unit 14 to encrypt the multicast data in the MLD / IGMP filter unit 13 received from the data distribution server 3 with the encryption key corresponding to the multicast communication based on the contents of the multicast management table 17. At this time, the LLID field included in the MAC preamble in the multicast data is set to “0xFFFF” broadcast. In the SecTAG area of the encrypted frame, the SCB flag and SC flag of the TCI field are set to “1”, and the SCI value stored in the multicast management table 17 is inserted into the SCI field. This encrypted multicast data is broadcasted to the ONU 2 by the PON-IF 10.

  Further, when the OLT 1 receives the unicast data from the SNI 11, the OLT 1 inputs the unicast data to the MLD / IGMP filter unit 13. The CPU 12 encrypts the unicast data in the MLD / IGMP filter unit 13 received from the data distribution server 3 to the encryption unit 14 with an encryption key corresponding to the unicast data communication based on the contents of the multicast management table 17. Make it. At this time, the LLID field included in the MAC preamble in the unicast data is set as the unicast LLID. In the SecTAG area of the encrypted frame, the SCB flag and SC flag of the TCI field are set to “0”, and the SCI field is not provided. The encrypted unicast data is unicast transmitted to the ONU 2 corresponding to the destination of the unicast data by the PON-IF 10.

  Here, the encryption algorithm GCM-AES applied by the encryption unit 14 and the decryption unit 15 of the OLT 1 according to the first embodiment will be described. In the GCM-AES, the encryption unit 14 forms the initial value IV of the counter used in the AES counter mode from 4 bytes of the PN field of the SecTAG and 8 bytes of the SCI field. Also, the hash key used for the ICV calculation is generated by a data encryption key and an AES counter mode encryption circuit provided in the encryption unit 14.

  Next, the configuration of the ONU 2 according to the first embodiment will be described. FIG. 7 is a block diagram of an ONU configuration according to the first embodiment. The ONU 2 is a subscriber side device (terminating device) that realizes encrypted multicast communication, and includes a PON interface (PON-IF) (transmitter) 30 connected to the OLT 1 via a splitter, and one or more subscriber terminals. 5 and the CPU 32 are provided. The functional configuration (functional division) illustrated in FIG. 7 is merely an example, and details of the PON-IF 30 and the UNI 31 are omitted.

  The PON-IF 30 includes an MLD / IGMP filter unit 33, an encryption unit 38, and a decryption unit 39. The MLD / IGMP filter unit 33 snoops MLD and IGMP Report messages and Leave messages as a multicast IP protocol from the UNI 31 (subscriber terminal 5), and MLD from the data distribution server 3 via PON (OLT1). And snoop the IGMP Query message.

  The encryption unit 38 holds an encryption key, and encrypts data to be transmitted to the OLT 1 using this encryption key. The decryption unit 39 holds a decryption key, and decrypts data received from the OLT 1 with this decryption key.

  The CPU 32 manages a multicast management table 34 that stores combinations of MAC address / multicast address / MLD, IGMP snoop result / encryption key / SCI. In addition, the CPU 32 includes a logical link control unit 35 that controls a logical link on the PON, and manages the LLID management table 36 that stores the usage status of the LLID value for each PON port by the logical link control unit 35.

  The CPU 32 also includes a unicast encryption key generation unit 40 and an MLD / IGMP monitoring unit 37 that monitors (snoops) MLD and IGMP messages. The CPU 32 includes means for controlling each function in the CPU 32, the PON-IF 30 and the UNI 31.

  The MLD / IGMP monitoring unit 37 reads information to be registered in the multicast management table 34 from various MLDs and IGMPs snooped by the MLD / IGMP filter unit 33 and causes the multicast management table 34 to register the information.

  Of the encryption keys (indexes) stored in the multicast management table 34, the multicast encryption key is notified from the OLT 1. The multicast encryption key notified from the OLT 1 is held and managed by the encryption unit 38 and the decryption unit 39.

  Of the encryption keys stored in the multicast management table 34, a unicast encryption key is generated for each LLID by the unicast encryption key generation unit 40, and held and managed by the encryption unit 38 and the decryption unit 39. . The unicast encryption key generated by the unicast encryption key generation unit 40 is encrypted by the encryption unit 38 based on the control of the CPU 32 and notified to the OLT 1.

  Here, the operation procedure of the ONU 2 will be described. First, an operation procedure when the ONU 2 receives data from the subscriber terminal 5 will be described. The ONU 2 receives the Report message transmitted from the subscriber terminal 5 based on the MLD or IGMP Query message from the data distribution server 3, and snoops and captures the Report message in the MLD / IGMP filter unit 33. In this Report message, an IP group address used for multicast communication is stored.

  The MLD / IGMP monitoring unit 37 reads the Report message and the MLD / IGMP snoop result. The MLD / IGMP monitoring unit 37 here reads information indicating “Report” from the MLD / IGMP filter unit 33 as the MLD / IGMP snoop result. The MLD / IGMP monitoring unit 37 searches the multicast management table 34 using the IP group address in the Report message as a key.

  Here, the configuration of the multicast management table 34 provided in the ONU 2 will be described. FIG. 8 is a diagram illustrating an example of a configuration of a multicast management table provided in the ONU. The multicast management table 34 includes the MAC address of the subscriber terminal 5, the multicast address (IP group address), the MLD / IGMP snoop result, the SCI corresponding to the multicast group, the encryption key for performing P2P communication with the OLT 1, OLT 1 Is an information table in which encryption keys are associated with each other when performing multicast communication.

  The multicast management table 34 is created using data (frames) transmitted / received between the OLT 1 and the data distribution server 3. For example, the SCI is based on an SCI (Optional) 75 in the SecTAG 62. Registered in

  For example, the multicast address of the subscriber terminal 5 whose MAC address is dd-dd-dd-dd-dd-dd, ee-ee-ee-ee-ee-ee is yy. yy. yy. yy, indicating that the MLD / IGMP MLD / IGMP snoop results from the subscriber terminal 5 are “Report” (Report message), respectively.

  Also, the P2P encryption key whose MAC address corresponds to dd-dd-dd-dd-dd-dd is # 1, and the P2P encryption key whose MAC address corresponds to ee-ee-ee-ee-ee-ee. Is # 4.

  The multicast address yy. yy. yy. The SCI corresponding to yy is “00 00 00 00 00 02 00 01”, indicating that the multicast encryption key is #B. The encryption key managed here is an index (identification information), and the actual encryption key is managed by the encryption unit 38 of the PON-IF 10.

  As a result of the IGMP monitoring unit 37 searching the multicast management table 34, if an IP multicast address corresponding to (matching with) the IP group address is not found, the MLD / IGMP monitoring unit 37 sends the report message to the subscriber terminal. 5 determines (recognizes) that it is the first group entry. Then, based on the Report message, the MLD / IGMP monitoring unit 37 adds the IP multicast address (IP group address), the MLD / IGMP snoop result (Report), and the index of the encryption key to be used to the unused entry in the multicast management table 34. And the SCI corresponding to the multicast group are stored. Thereby, even if the subscriber terminal 5 is the first entry, it becomes possible to perform a decoding process based on the SCI, a multicast frame reception process, and the like.

  Next, processing when an IP multicast address that matches an IP group address included in an MLD or IGMP Report message is found from an entry in the multicast management table 34 will be described.

  As a result of the MLD / IGMP monitoring unit 20 searching the multicast management table 17, when an IP multicast address corresponding to (matching with) the IP group address is found, the MLD / IGMP monitoring unit 20 transmits the report message. The terminal 5 determines (recognizes) that it is the second and subsequent group entry. Then, the MLD / IGMP monitoring unit 20 stores the new subscriber terminal 5 (such as a MAC address) in an entry having a matching IP multicast address in the multicast management table 17. Thereby, even if the subscriber terminal 5 is the second or later entry, it is possible to perform a decoding process based on the SCI, a multicast frame reception process, and the like.

  The unicast data from the subscriber terminal 5 received from the UNI 31 is snooped by the MLD / IGMP filter unit 33 in the case of an MLD or IGMP message, and corresponds to the unicast communication based on the contents of the multicast management table 34. After encrypting with the encryption key, it is transferred to the PON-IF 30. At this time, the LLID field included in the MAC preamble is a unicast LLID, and the SECTAG area of the encrypted frame has the SCB flag and SC flag of the TCI field set to “0”, and the SCI field is not provided.

  Next, an operation procedure when the ONU 2 receives data from the data distribution server 3 side will be described. Multicast data and unicast data transmitted by the data distribution server 3 are transmitted to the ONU 2 via the OLT 1. When receiving the multicast data from the PON-IF 30, the ONU 2 inputs this multicast data to the IGMP filter unit 33. The CPU 32 causes the decoding unit 39 to decode this multicast data. At this time, the decryption unit 39 decrypts with the decryption key corresponding to the multicast communication based on the contents of the multicast management table 34. When the SC flag of the encrypted frame is “1”, the decryption unit 39 compares the SCI field with the SCI value stored in the multicast management table 34 and decrypts the data with the decryption key corresponding to the group. The multicast data decoded by the decoding unit 39 is transferred to the UNI 31 and transmitted to the subscriber terminal 5.

  When the OLT 1 receives unicast data from the PON-IF 30, the OLT 1 inputs the unicast data to the MLD / IGMP filter unit 33. The CPU 32 causes the decryption unit 39 to decrypt the unicast data in the MLD / IGMP filter unit 33 with the decryption key corresponding to the unicast data communication based on the contents of the multicast management table 34. At this time, the decryption condition performed by the decryption unit 39 follows the SecTAG area of the encrypted frame. The unicast data decoded by the decoding unit 39 is transferred to the UNI 31 and transmitted to the subscriber terminal 5.

  Next, an encryption key distribution method will be described. The OLT 1 sets a unique encryption key Type for each PON in the ME (MAC Ether Type field) 15 of the SecTAG 62. The OLT 1 or ONU 2 receiving the encryption key decrypts the encrypted data and extracts the key information, and then discards the frame and does not transfer it outside the PON.

  Next, a first distribution method and a second distribution method of the multicast encryption key will be described. The first method can be applied to key update when no subscriber (subscriber terminal 5) has left the multicast group, and the second method can be applied when any subscriber leaves the multicast group; Applicable to both key renewals when no subscriber has left.

  In the first multicast encryption key distribution method, similar to the multicast data transmission method, the OLT 1 sets both the SCB flag and the SC flag of the SecTAG field to “1” and is stored in the multicast management table 17 of the OLT 1. Insert SCI and output to PON by broadcast. When receiving the multicast encryption key from the PON-IF 30, the ONU 2 decrypts it according to the SecTAG field, stores the index of the multicast encryption key in the multicast management table 34, as well as the multicast data reception method, and encrypts the unit 38. To manage multicast encryption keys.

  In the second multicast encryption key distribution method, the OLT 1 sets both the SCB flag and the SC flag in the SecTAG field to “0”, as in the unicast data transmission method, and is based on the LLID management table 19 of the OLT 1. And output to PON by unicast. When receiving the multicast encryption key from the PON-IF 30, the ONU 2 decrypts the multicast encryption key according to the SecTAG field, stores the index of the multicast encryption key in the multicast management table 34, and encrypts the encryption unit. 38 manages multicast encryption keys.

  As described above, in the PON system 100, the OLT 1 and the ONU 2 are the encryption tag type information (ME71) indicating that the transmission data is encrypted, and the encryption tag field (the encryption tag field indicating the encryption tag information indicating the data encryption information). TCI / AN72), a packet data field (SecTAG62) indicating transmission data (encrypted data) encrypted based on information related to encryption, and an integrity check field (ICV63) for checking the integrity of the encrypted data are formed. Each of these fields and a destination address (DA) of transmission data and an address field (SA) indicating a transmission source address form one transmission frame.

  The encryption tag field optionally includes a multicast group information field (SCI75), a flag bit area (SCB) indicating a broadcast frame, and a flag bit area (SC) indicating the presence or absence of the group information field. And have.

  Thereby, the ONU 2 and the OLT 1 can determine whether the received data frame should be encrypted / decrypted, and which encryption key / decryption key should be used to encrypt / decrypt the data frame based on the SCI 75 Can be judged. Accordingly, encrypted data broadcast communication is possible in data transmission from the OLT 1 to the ONU 2.

  As described above, according to the first embodiment, the multicast data transmitted in the PON section can be secured by encrypting with the encryption key for each IP group address, and is distributed to the ONU 2 by broadcast. The network bandwidth can be used efficiently without squeezing the transmission bandwidth.

Embodiment 2. FIG.
The GCM-AES encryption method is an encryption algorithm that is applied even outside the PON interval. For this reason, it may be encrypted by a device outside the PON section. For example, when encryption is performed by the data distribution server 3 higher than the OLT 1, the OLT 1 checks the encryption flag (E (Encryption)) in the SecTAG field 62 of the frame received from the SNI 11, and if “1” is not set. Encryption is performed and the encryption flag is set to “1” to transfer the encrypted frame to the PON. At this time, if the frame is a multicast address frame, the broadcast LLID of “0xFFFF” is inserted into the LLID field of the MAC preamble, and the SCB flag of the SecTAG field 62 is set.

  When the ONU 2 receives the encrypted frame encrypted by the data distribution server 3, the multicast address stored in the multicast management table 34 is searched, and if the decryption key corresponding to the encrypted frame is held, the decryption is performed. This is decoded by the conversion unit 39. Thereby, it is possible to transmit a frame from the OLT 1 to the ONU 2 even for a frame encrypted outside the PON section.

  On the other hand, if the ONU 2 does not have an encryption key corresponding to the encrypted frame, the encrypted frame is transferred to the subordinate subscriber terminal 5 without being decrypted. In addition, in the encrypted frame from OLT1, when Type (decryption instruction information) indicating that ONU2 does not decrypt is set in the ME (MAC Ether Type) 71 field of SecTAG62, ONU2 decrypts the encrypted frame. Without being transferred to the subordinate subscriber terminal 5 as it is. At this time, the encrypted frame desired to be decrypted by the ONU 2 is processed by the subordinate subscriber terminal 5. As a result, even if the ONU 2 does not have an encryption key corresponding to the encrypted frame, the subscriber terminal 5 can acquire the encrypted frame from the OLT 1.

  Similarly, when encryption is performed at the subscriber terminal 5 under the ONU 2, the ONU 2 encrypts unless “1” is set in the encryption flag (E (Encryption)) of the SecTAG field 62 of the frame received from the UNI 31. And the encryption flag is set to “1” and the encrypted frame is transferred to the PON.

  When the OLT 1 receives the encrypted frame, the multicast address stored in the multicast management table 17 is searched. If the decryption key corresponding to the frame is held, the decryption unit 15 decrypts it. If it does not have an encryption key corresponding to the frame, it is transferred to the upper IP network 101 without being decrypted. As a result, even if the frame is encrypted outside the PON section, it is possible to transmit the frame from the ONU 2 to the OLT 1. Even if the OLT 1 does not have a decryption key corresponding to the encrypted frame, the encrypted frame from the subscriber terminal 5 can be transmitted to the IP network 101.

  Moreover, OLT1 and ONU2 may produce | generate the flame | frame peculiar to a PON area uniquely. These frames can be encrypted and transmitted in the same manner as frames transmitted outside the PON system 100. For example, in the case of a frame addressed to unicast, the OLT 1 and ONU 2 may set the SC flag in the SecTAG field 62 to “0” and insert the unicast LLID into the MAC preamble. In the case of a frame addressed to a multicast, the OLT 1 sets and stores the SCI corresponding to the multicast address in the multicast management table 17, sets the SCB flag and SC flag of the SecTAG field to “1”, and sets the SCI field. The SCI value stored in the multicast management table 17 may be inserted and transmitted to the PON. At this time, the broadcast LLID is inserted into the LLID area of the MAC preamble.

  For a frame specific to the PON section, a Type indicating that it is an encrypted frame unique to the PON section is set in the ME (MAC Ether Type) 71 field of the SecTAG 62 (addition of PON specific information). Thus, the OLT 1 and the ONU 2 decode the data and extract the information, and then discard the frame and do not transfer it outside the PON. As a result, the frame specific to the PON section is processed within the PON section, and it is possible to prevent the frame specific to the PON section from flowing out of the PON section.

  An encryption key distribution method for encrypting a frame unique to the PON section will be described. An encryption key Type unique to the PON is set in the ME (MAC Ether Type) 71 field of the SecTAG62. The OLT 1 or ONU 2 receiving the encryption key decrypts the encrypted data and extracts the key information, and then discards the frame and does not transfer it outside the PON. Thereby, the key information peculiar to the PON section is processed in the PON section, and it is possible to prevent the key information peculiar to the PON section from flowing out of the PON section.

  As described above, according to the second embodiment, data encrypted outside the PON section can be transmitted through the PON section in a state where security is ensured, and the multicast frame is distributed by broadcast, so that the band can be used efficiently. . Further, since the frame unique to the PON section is also encrypted and the frame is not transferred outside the PON, security can be enhanced.

  As described above, the station-side device, the subscriber-side device, and the PON system according to the present invention are suitable for data communication that maintains confidentiality.

It is a figure which shows the structure of the PON system concerning Embodiment 1 of this invention. It is a figure which shows an example of the frame format transmitted in a PON system. It is a figure for demonstrating the detailed structure of a SecTAG field. It is a figure for demonstrating the protocol stack of a PON system. 1 is a block diagram showing a configuration of an OLT according to a first exemplary embodiment. It is a figure which shows an example of a structure of the multicast management table with which OLT is provided. 1 is a block diagram showing a configuration of an ONU according to a first embodiment. It is a figure which shows an example of a structure of the multicast management table with which ONU is provided.

Explanation of symbols

1 OLT
2 ONU
3 Data distribution server 4 Switch 5 Subscriber terminal 10, 32 CPU
11 SNI
12,30 PON-IF
13, 33 MLD / IGMP filter unit 14, 38 Encryption unit 15, 39 Decryption unit 16 Multicast monitoring unit 17, 34 Multicast management table 18, 35 Logical link control unit 19, 36 LLID management table 20, 37 MLD / IGMP monitoring Unit 21 Multicast encryption key generation unit 31 UNI
40 Unicast Encryption Key Generation Unit 100 PON System 101 IP Network

Claims (14)

A subscriber side device accommodating a plurality of subscriber terminals is connected to an IP network through an optical transmission medium on a PON system, and the subscriber side device is connected to the IP network by a predetermined data frame on the optical transmission medium. In the station side device that sends and receives data to and from
A snoop unit that snoops a control message used to control multicast communication;
An encryption key generation unit for generating a multicast encryption key based on the snoop result of the snoop unit;
A multicast cipher corresponding to the multicast identifier of the multicast group based on a multicast management table relating to the multicast encryption key generated by the encryption key generation unit and the multicast identifier identifying the multicast group of the subscriber terminal An encryption unit that selects a key and encrypts the multicast frame to the multicast group with information related to encryption; and
A transmission unit that broadcasts the multicast frame encrypted by the encryption unit to the subscriber side device; and
A station-side device comprising: A storage unit for storing the multicast management table;
The storage unit stores the multicast address in the control message snooped by the snoop unit in association with the subscriber side device that has transmitted the control message,
When transmitting a multicast frame to the subscriber side device, the transmission unit selects a multicast identifier corresponding to the multicast address of the subscriber side device based on information in the storage unit, and selects the selected multicast identifier The station-side apparatus according to claim 1, wherein the station-side apparatus transmits the multicast frame.   When the multicast identifier of the subscriber side device that is the transmission source of the control message snooped by the snoop unit is stored in the multicast management table, the storage unit transmits the control message in association with the multicast identifier. The station-side apparatus according to claim 2, wherein information on the original subscriber terminal is stored in the multicast management table.   When the encryption unit receives a data frame encrypted in an encrypted data format when encrypting a multicast frame from the IP network, the data frame received from the IP network is not encrypted. The station apparatus according to any one of claims 1 to 3, further comprising a control unit configured to control transfer to an optical transmission medium.   When the data frame to the subscriber side device is a data frame specific to the PON interval with the subscriber side device, the control unit is specific to the PON interval with the subscriber side device. The station apparatus according to any one of claims 1 to 3, wherein a data frame to which PON specific information indicating a frame is added is transmitted to the subscriber apparatus.   When the control unit receives a data frame including the PON specific information from the subscriber side device, the control unit extracts information in the data frame, and then controls to discard the data frame and not transfer the data frame to the IP network. The station apparatus according to claim 5, wherein The station side device connected to the IP network is connected via an optical transmission medium on the PON system and accommodates one to a plurality of subscriber terminals, and is connected to the station side device by a predetermined data frame on the optical transmission medium. In the subscriber side device that sends and receives data between
A snoop unit that snoops a control message used to control multicast communication;
A decryption key acquisition unit for acquiring a multicast decryption key transmitted from the station side device;
Multicast of the multicast group based on the multicast management table related to the association between the multicast decryption key acquired by the decryption key acquisition unit and the multicast identifier for identifying the multicast group of the subscriber terminal and the snoop result of the snoop unit A decryption unit for selecting a multicast decryption key corresponding to the identifier and decrypting a multicast frame broadcast from the station side device;
A subscriber-side device comprising: A storage unit for storing the multicast management table;
The storage unit stores the multicast address in the control message snooped by the snoop unit in association with the subscriber terminal that has transmitted the control message,
When the decoding unit receives a multicast frame from the station side device, the decoding unit extracts a multicast identifier corresponding to the multicast address of the subscriber side device accommodating the subscriber terminal from the multicast frame, and extracts the extracted multicast identifier. 8. The subscriber side apparatus according to claim 7, wherein a corresponding multicast decryption key is selected from the storage unit and the multicast frame is decrypted.   The storage unit stores the multicast identifier of the subscriber terminal that is the transmission source of the control message snooped by the snoop unit in the multicast management table, and associates the transmission source of the control message with the multicast identifier. 9. The subscriber-side apparatus according to claim 8, wherein information related to a subscriber terminal is stored in the multicast management table. The multicast frame from the station side device includes decoding instruction information for instructing whether or not to decode the multicast frame by the decoding unit,
A control unit that controls to transfer a multicast frame from the station side device to the subscriber terminal without decoding when the decoding instruction information is information indicating that the decoding unit does not perform decoding; The subscriber-side device according to any one of claims 7 to 9, further comprising:   The control unit is a frame specific to the PON section with the station side device when the data frame to the station side apparatus is a data frame specific to the PON section with the station side device. The subscriber-side device according to claim 10, wherein the subscriber-side device is controlled to transmit a data frame to which the PON specific information indicating that is added to the station-side device.   When the control unit receives a data frame including the PON specific information from the station side device, the control unit extracts the information in the data frame, and then controls to discard the data frame and not transfer the data frame to the subscriber terminal. The subscriber side apparatus according to claim 10, wherein   The subscriber-side device according to any one of claims 7 to 12, wherein a multicast identifier of the multicast management table is notified from the station-side device. A subscriber-side device that accommodates one or more subscriber terminals and a station-side device that accommodates the subscriber-side device and is connected to an IP network are connected by a transmission medium, and the subscriber is connected by a predetermined data frame. In a PON system that transmits and receives data between a side device and the station side device,
The station side device
A first snoop unit that snoops a control message used to control multicast communication;
An encryption key generation unit for generating a multicast encryption key based on the snoop result of the first snoop unit;
Corresponds to the multicast identifier of the multicast group based on the first multicast management table related to the correspondence between the multicast encryption key generated by the encryption key generator and the multicast identifier for identifying the multicast group of the subscriber terminal An encryption unit that selects a multicast encryption key and encrypts the multicast frame to the multicast group by adding information related to encryption; and
A transmission unit that broadcasts the multicast frame encrypted by the encryption unit to the subscriber side device; and
With
The subscriber side device is:
A second snoop unit that snoops a control message used to control multicast communication;
A decryption key acquisition unit for acquiring a multicast decryption key transmitted from the station side device;
Based on the second multicast management table related to the correspondence between the multicast decryption key acquired by the decryption key acquisition unit and the multicast identifier for identifying the multicast group of the subscriber terminal, and the snoop result of the snoop unit, the multicast Selecting a multicast decryption key corresponding to the multicast identifier of the group, and decrypting the multicast frame from the station side device; and
A PON system comprising:

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