JP2013009271A - Olt and frame transfer method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To transfer frames to be communicated between a plurality of ONUs and a plurality of host devices by using one OLT avoiding a large increase of a circuit scale and a restriction to a downlink bandwidth.SOLUTION: On a MAC address retrieval table 27, a relevant ONU LLID and downlink output destination selection information are pre-registered for each MAC address of a user device connected to the ONU. When downlink frames are received from a host device, a frame transfer processing part 20 obtains an LLID corresponding to the destination MAC address of the downlink frames and the downlink output destination selection information from the MAC address retrieval table 27. On an LLID table 23, SNI selection information corresponding to the LLID is pre-registered for each LLID of an ONU. When uplink frames are received from an ONU, the frame transfer processing part 20 obtains the SNI selection information corresponding to the uplink frame LLID from the LLID table 23.

Description

  The present invention relates to an optical communication technique, and more particularly, to a frame transfer technique in an OLT (Optical Line Terminal) for connecting a PON system to a host device of a provider side network (service network).

  In 2009, standardization of 10G-EPON (10 Gigabit Ethernet Passive Optical Network: Ethernet is a registered trademark) was completed in IEEE 802.3av. The characteristic of 10G-EPON is that 10-times high-speed transmission is possible as compared with GE-PON (Gigabit Ethernet Passive Optical Network: see Non-Patent Document 1) that is already widely used. Furthermore, there is a feature that existing GE-PON and 10G-EPON can be used together.

  When using a mixture of GE-PON and 10G-EPON, use WDM technology that uses different wavelengths for 1G downstream signals and 10G downstream signals, and use TDM technology between 1G downstream signals and between 10G downstream signals. . In the upstream signal, the same wavelength is used for the 1G upstream signal and the 10G upstream signal, and the TDMA technique is used by combining the 1G upstream signal and the 10G upstream signal. That is, three different wavelengths are used for the 1G downstream signal, the 10G downstream signal, and the upstream signal.

[First prior art]
First, the first prior art will be described. FIG. 19 is a configuration example of a conventional 10G-EPON system. As shown in FIG. 19, in 10G-EPON, GE-PON and 10G-EPON can be used together, so 1G-ONU (Optical Network Unit) and 10G-ONU can be connected to one OLT. .
FIG. 20 is a block diagram showing a configuration of a conventional OLT (see Patent Document 1). FIG. 21 is a block diagram showing a main configuration of a frame transfer process used in the conventional OLT.

  In the conventional OLT, the frame transfer processing unit 60 determines the destination ONU of the downstream frame based on the destination MAC address of the downstream frame. For this reason, the MAC address registration unit 61A registers the transmission source MAC address of the received upstream frame in the MAC address search table 61B by binding the LLID (Logical Link ID) of the transmission source ONU. If the destination MAC address of the received downstream frame is already registered in the MAC address search table 61B, the MAC address search unit 61C has a function of determining the LLID bound to the MAC address as the destination ONU. ing.

In the OLT of FIG. 20, the first transmission / reception circuit 52 is a circuit for transmitting / receiving a frame to / from the ONU via the PON connected to the PON port 51.
The second transmission / reception circuit 58 is a circuit that becomes an interface with the operator network NW connected via the SNI port 59 provided on the SNI (Service Node Interface) side.
The frame separation unit 53 transmits a frame (control frame used for PON control) addressed to the OLT 50 among the frames received from the first transmission / reception circuit 52 to the control frame processing unit 54, and transmits other frames to the frame. It is a processing unit that transmits to the transfer processing unit 60.

The frame multiplexing unit 56 is a processing unit that multiplexes the downlink frame from the frame transfer processing unit 60 and the control frame from the control frame processing unit 54 in a time division manner and transmits the multiplexed frames to the first transmission / reception circuit 52.
The frame transfer processing unit 60 is a processing unit that performs frame transfer processing on frames received from both the frame separation unit 53 and the second transmission / reception circuit 58 based on respective destination MAC addresses.

The control frame processing unit 54 performs processing related to PON control such as discovery processing (Discovery process) for automatically assigning LLID to each ONU and arbitration of an upstream signal (signal addressed to the OLT from the ONU), and the LLID of each ONU. Is a processing unit that performs a process of transferring the PON-IF port information such as to the bandwidth allocation processing unit 55.
The bandwidth allocation processing unit 55 manages the processing for allocating bandwidth (transmission start time and transmission data amount) to the ONU and the PON-IF port information transferred from the control frame processing unit 54 according to the request from the control frame processing unit 54. It is a processing part which performs the process to perform.

Further, in the MAC address processing unit 61 that performs MAC address registration / search in the frame transfer processing unit 60 of FIG. 21, the MAC address registration unit 61A searches for the MAC address based on the source MAC address of the received upstream frame. The table 61B is searched. If the source MAC address is not registered in the MAC address search table 61B, it is newly registered. If the source MAC address is already registered in the MAC address search table 61B, the registration information is updated. (If the registration information does not need to be changed, it may not be updated).
The LLID of the ONU corresponding to each source MAC address is registered in the MAC address search table 61B.

Based on the received destination MAC address of the downlink frame, the MAC address search unit 61C reads the corresponding LLID from the MAC address search table 61B and determines the LLID to be given to the downlink frame.
The latency absorbing unit 61D adds a delay to the received downlink frame, and absorbs the latency due to the LLID determination process in the MAC address searching unit 61C.
The output combining unit 61E adds the destination LLID to the downlink frame to be transmitted by inserting the LLID determined by the MAC address search unit 61C into the preamble of the downlink frame output from the latency absorbing unit 61D.

  In the 10G-EPON system, the LLID of the destination ONU can be determined in the same manner when the downlink frames addressed to the 1G-ONU and the 10G-ONU are mixed, but the LLID of which type of ONU It is necessary to check separately whether it is a downstream frame output at the corresponding rate. However, such a function is not installed in the conventional OLT.

  FIG. 22 is a block diagram showing a main configuration (after change) of a frame transfer process used in a conventional OLT. In a conventional OLT, a LLID of a destination ONU is determined from a destination MAC address of a downstream frame, a downstream transmission rate information is determined from the LLID, and a circuit for adding the information to the downstream frame is added (that is, 10G It is considered that the downlink transmission rate processing unit 62 as shown in FIG. 22 is necessary in the frame transfer processing unit 60.

In FIG. 22, the speed information registration unit 62A acquires the LLID of the transmission source ONU from the received preamble of the upstream frame, reads the downlink transmission speed information corresponding to the LLID of the transmission source ONU from the band allocation processing unit 55, The LLID and the downlink transmission rate information are associated with each other and registered in the downlink transmission rate management table 62B.
In the downlink transmission rate management table 62B, downlink transmission rate information corresponding to the LLID of each ONU is registered.
The downlink transmission rate search unit 62C reads the downlink transmission rate information from the downlink transmission rate management table 62B based on the destination LLID of the downlink frame, and determines the downlink transmission rate information of the downlink frame to be transmitted.

The second latency absorbing unit 62D adds a delay to the downlink frame to which the destination LLID is added, and absorbs the latency due to the downlink transmission rate determining process in the downlink transmission rate searching unit 62C.
The second output combining unit 62E gives the downlink transmission rate information read out by the search in the downlink transmission rate search unit 62C to the downlink frame output from the second latency absorbing unit 62D.
The downlink frame is sent to the PON at a predetermined rate according to the assigned downlink transmission rate information.

  In FIG. 22, the downlink transmission rate information is input from the uplink frame and band allocation processing unit 55 to the rate information registration unit 62A. Such a registration circuit (rate information registration unit 62A) Is not necessarily required. Since the software for controlling and managing the OLT 50 grasps the downlink transmission rate information for each LLID, it is possible to write necessary information in the downlink transmission rate management table 62B by this software.

[Second prior art]
Next, the second prior art will be described. FIG. 23 shows another configuration example of the conventional 10G-EPON system. FIG. 24 shows another configuration example of the conventional 10G-EPON system.
In the conventional PON system, as shown in Non-Patent Document 2, the OLT is provided with one SNI port on the SNI (Service Node Interface) side.

  Accordingly, when it is necessary to change the network (service network) to be connected for each ONU (Optical Network Unit), the conventional PON system has a system configuration as shown in FIG. Among these, the system configuration in FIG. 23 is a configuration example in which one OLT is provided for each network (service network) NW. The system configuration of FIG. 24 is a configuration example in which a switch (or a router or the like) is inserted between the OLT and the plurality of networks NW, and the plurality of networks NW are connected to one OLT. The OLT used in these PON systems is the same OLT as that shown in FIG.

  In both the system configurations of FIG. 23 and FIG. 24, a host device that performs transfer control and the like in the service network is inserted between the SNI and the network NW. At this time, the content of the service that can be realized by the PON system is limited by the host device connected to the OLT. For example, when the host device connected to the OLT is for 1G Ethernet, this PON system is limited to services by 1G Ethernet.

  In the case of FIG. 24, one switch and OLT are shared by a plurality of higher-level devices, that is, the bandwidth for one OLT is divided and used. For this reason, compared with the case of FIG. 23, the band of the downstream frame which can be used by each higher rank apparatus will become small.

In other words, when the network NW connected to each ONU is different, there have been two methods in the past.
Method 1 (FIG. 23): The maximum downlink bandwidth that can be used by each host device can be maximized, but the same number of OLTs as the network NW to be connected is required. Method 2 (FIG. 24): The downlink bandwidth that can be used by each host device is Method 1 ( Although it is smaller than that of FIG. 23 (the downstream bandwidth of the host device cannot be used to the maximum), if only one OLT is required, both have advantages and disadvantages.

JP 2009-260668 A

“Technology Basic Course [GE-PON Technology] 1st PON”, NTT Technical Journal, Vol.17, No.8, pp.71-74, 2005 “Development of Gigabit Ethernet-PON (GE-PON) System”, NTT Technical Journal, Vol.17, No.3, pp.75-80, 2005

  In the first prior art described above, when 1G-ONU and 10G-ONU are connected to one OLT, it is necessary to add hardware for executing transmission rate determination processing. However, the hardware for executing the transmission rate determination process has a circuit scale similar to that of the MAC address processing unit 61 for executing the LLID determination process, such as the downlink speed information processing unit 62 shown in FIG. It becomes. For this reason, there has been a problem that the circuit scale of the OLT becomes large and the apparatus becomes large. Further, due to such an increase in circuit scale, there is a problem that power consumption, frame transfer delay time, and device cost increase.

In the second prior art described above, when a plurality of networks (service networks) NW are connected to one OLT, according to Method 1, the same number of OLTs as the number of networks (service networks) to be connected is required. Method 2 is desirable when considering the number of OLTs in the entire PON system.
However, according to the method 2, it is necessary to insert a switch (or a router or the like) between the OLT and the host device of each network NW. For this reason, each upper apparatus shares the downstream band of the switch, and there is a problem that the downstream band that can be used by each upper apparatus is limited.

  The present invention is for solving such problems, and exchanges between a plurality of ONUs and a plurality of higher-level devices by one OLT while avoiding a significant increase in circuit scale and a restriction on the downstream band. An object of the present invention is to provide a frame transfer technique capable of transferring a frame to be transmitted.

  In order to achieve such an object, the OLT according to the present invention is connected to a plurality of ONUs via PONs, and is connected to a plurality of higher-level devices via SNI provided for each higher-level device. Is an OLT that mutually transfers frames exchanged between the host device and the host device, and is provided with a receiving circuit that receives an upstream frame from the ONU via the PON, and a transmission rate that is set in advance. A plurality of transmission circuits that transmit the downstream frame to the SNR at the transmission speed and each SNI, and transmits the upstream frame to the higher-level device via the SNI, and via the SNI A plurality of transmission / reception circuits that receive downstream frames from the higher-level device and an upstream frame received by the reception circuit are transferred to the transmission / reception circuits. A frame transfer processing unit that transfers the received downlink frame to the transmission circuit, and the frame transfer processing unit includes, for each individual LLID, an LLID table in which SNI selection information corresponding to the LLID is registered, and an ONU SNI corresponding to the LLID of the upstream frame received by the receiving circuit, and the MAC address search table in which the LLID of the ONU and the downstream output destination selection information are registered for each individual MAC address in the user apparatus connected to The selection information is acquired from the LLID table, the uplink frame is transferred to the transmission / reception circuit corresponding to the SNI selection information in the transmission / reception circuit, and the LLID and the downlink output destination corresponding to the destination MAC address of the downlink frame received by the transmission / reception circuit The selection information is acquired from the MAC address search table, and the L After the application in the downlink frame ID, it is obtained so as to transfer to the transmission circuit corresponding with the downstream output destination selection information of the transmission circuit.

  At this time, the frame transfer processing unit receives an SNI selection information corresponding to the LLID of the upstream frame received by the receiving circuit from the LLID table, and the SNI selection acquired by the output destination determining unit among the transmission / reception circuits. An uplink output destination control unit that transfers the uplink frame to the transmission / reception circuit corresponding to the information may be further included.

  The frame transfer processing unit is provided for each transmission / reception circuit, and a plurality of downlinks for acquiring LLID and downlink output destination selection information corresponding to the destination MAC address of the downlink frame received by the transmission / reception circuit from the MAC address search table. Provided for each output destination determination unit and each transmission / reception circuit, for each of the transmission / reception circuits, a plurality of LLID addition units for adding the LLID acquired by the downlink output destination determination unit to the downlink frame received by the transmission / reception circuit. A plurality of downlink output destination control units that transfer the downlink frame from the LLID adding unit to the transmission circuit corresponding to the downlink output destination selection information acquired by the downlink output destination determination unit of the transmission circuit. You may make it.

  In addition, the frame transfer processing unit acquires the transmission source MAC address and LLID from the upstream frame received by the reception circuit, and sends the LLID and the downlink output destination selection information previously associated with the LLID to the transmission source MAC. A MAC address registration unit for registering in the MAC address search table in association with the address may be further included.

  In addition, for the upstream frame received by the receiving circuit, further comprising an upstream input unit for giving downstream output destination selection information associated with the upstream frame LLID in advance to the upstream frame, the MAC address registration unit, The source MAC address, the LLID, and the downlink output destination selection information may be acquired from the uplink frame output from the uplink input unit and registered in the MAC address search table.

  Further, when the LLID and the downlink output destination selection information are registered in the MAC address registration unit, the MAC address search table is registered in the MAC address search table including the reception status related to the transmission source MAC address, and every predetermined aging period. It is also possible to check the reception status of each MAC address registered in, and set a MAC address that has not been confirmed to be received within the aging period among these MAC addresses to an invalid state.

  The frame transfer processing unit further includes a VID table in which the LLID and the downlink output destination selection information related to the downlink frame are registered for each VID for identifying the VLAN to which the downlink frame belongs. The LLID and downlink output destination selection information regarding the frame may be acquired from the MAC address search table based on the destination MAC address of the downlink frame, or may be acquired from the VID table based on the VID of the downlink frame.

  In addition, the frame transfer method according to the present invention connects to a plurality of ONUs via PON and connects to a plurality of host devices via SNI provided for each host device, and between these ONUs and host devices. A frame transfer method used in the OLT for mutually transferring a frame exchanged in each of the ONUs, for each individual LLID, storing a SNI selection information corresponding to the LLID in an LLID table, and being connected to the ONU A step of storing the LLID of the ONU and the downlink output destination selection information in a MAC address search table for each individual MAC address of the user apparatus, and SNI selection information corresponding to the LLID of the upstream frame received from the ONU via the PON Is obtained from the LLID table and provided for each SNI. Among the transmission / reception circuits that transmit / receive frames to / from the higher-level device, the step of transferring the uplink frame to the transmission / reception circuit corresponding to the SNI selection information, and the correspondence to the destination MAC address of the downlink frame received by the transmission / reception circuit LLID and downlink output destination selection information to be acquired from the MAC address search table, the LLID is assigned to the downlink frame, and the downlink frame to the ONU is provided via the PON. A step of transferring to a transmission circuit corresponding to the downlink output destination selection information among a plurality of transmission circuits transmitting at a transmission rate.

According to the present invention, the destination LLID of the downstream frame and the downstream output destination selection information (transmission speed) can be determined only by reading (searching) from the MAC address search table, so that the circuit scale of the OLT is almost increased. The output system of the downstream frame can be specified without any problem.
Further, when the OLT is connected to a plurality of higher-level devices via SNI provided for each higher-level device, an upstream frame received from any ONU connected to the PON system is connected to each SNI port. Among each of the higher-level devices, it can be transferred to a higher-level device corresponding to the ONU. In addition, it is possible to process downstream frames input via a plurality of SNI ports in parallel for each input SNI port and transfer them to the destination ONU. Therefore, between each ONU of the PON system and each host device, and further each network, one OLT having a port for each SNI without a switch or the like between the OLT and a plurality of SNIs. The frame can be transferred. For this reason, it is possible to avoid sharing the downstream band of the switch among the higher-level devices, and to avoid restrictions on the downstream bandwidth that can be used by the individual higher-level devices.

It is a block diagram which shows the structure of the PON system concerning 1st Embodiment. It is a structural example of the frame transmitted in a PON section. It is a block diagram which shows the structure of OLT concerning 1st Embodiment. It is a block diagram which shows the structural example of a frame transfer process part. It is a structural example of a MAC address search table. It is a flowchart which shows the output destination determination procedure of a downstream frame. It is an example of a structure of a LLID table. It is a flowchart which shows the output destination SNI determination procedure of an upstream frame. It is a block diagram which shows the structure of OLT concerning 2nd Embodiment. It is an example of a structure of the upstream frame output from an upstream input part. It is a flowchart which shows a MAC address registration process. It is another example of a structure of a MAC address search table. It is another flowchart which shows a MAC address registration procedure. It is a flowchart which shows an aging processing procedure. It is a time chart which shows transition of the entry in a MAC address search table. It is a block diagram which shows the structure of the frame transfer process part concerning 4th Embodiment. It is a structural example of a VID table. It is a flowchart which shows the output destination determination procedure of a downstream frame. It is a structural example of the conventional 10G-EPON system. It is a block diagram which shows the structure of the conventional OLT. It is a block diagram which shows the principal part structure of the frame transfer process used by the conventional OLT. It is a block diagram which shows the principal part structure (after change) of the frame transfer process used by the conventional OLT. It is another structural example of the conventional 10G-EPON system. It is another structural example of the conventional 10G-EPON system.

Next, embodiments of the present invention will be described with reference to the drawings.
[PON system]
First, a PON system 100 according to a first embodiment of the present invention will be described with reference to FIG. 1 and FIG. FIG. 1 is a block diagram showing the configuration of the PON system according to the first embodiment. FIG. 2 is a configuration example of a frame transmitted in the PON section.

As shown in FIG. 1, in this PON system 100, ONUn (n = 1-6) is connected to the user apparatus n via UNI (User Network Interface).
Each ONU is commonly connected to one optical splitter via an optical communication path, and this optical splitter is further connected to one OLT 10 via one optical communication path and an optical demultiplexing device. .

The OLT 10 is provided with two SNI ports on the SNI side, and the higher order apparatus 1 and the higher order apparatus 2 are individually connected to each SNI port via the SNI.
Further, a network (service network) NW1 on the operator side is connected to the host device 1, and a network (service network) NW2 on the operator side is connected to the host device 2.

In the PON section of the PON system 100, that is, the section between the ONUn and the OLT 10, data is exchanged in a frame configured as shown in FIG.
In FIG. 2, the preamble is an LLID embedded in the Ethernet preamble.

  The LLID (Logical Link ID) is an identifier that has a one-to-one correspondence with each ONU. It is determined by the OLT at the time of ONU registration (ONU is under the control of the OLT), and the OLT manages the ONU under its control so that duplication of LLID does not occur.

The VLAN tag is a tag including VLAN information. There may be no tag or multiple tags. This VLAN tag includes TPID and TCI.
TPID (Tag Protocol ID) is an Ether Type value indicating that a VLAN tag continues. Usually 0x8100.
TCI (Tag Control Information) is VLAN tag information. This TCI includes PCP, CFI, and VID.

PCP (Priority Code Point) is the priority of the frame.
CFI (Canonical Format Indicator) is a value indicating whether or not the MAC address in the MAC header conforms to the standard format.
The VID or VLAN ID (VLAN Identifier) is a value that specifies the VLAN to which the frame belongs.
Type is an Ether Type value indicating the type of the upper protocol.

[OLT]
Next, the configuration of the OLT 10 according to the present embodiment will be described with reference to FIG. FIG. 3 is a block diagram illustrating a configuration of the OLT according to the first embodiment.
The difference in configuration of the OLT 10 according to the present embodiment from the conventional OLT is that an SNI port, a transmission / reception circuit, a frame multiplexing unit, and a transmission circuit are provided for each transmission system having different transmission speeds. A frame transfer processing unit having a configuration corresponding to the SNI port, the transmission / reception circuit, the frame multiplexing unit, and the transmission circuit provided for each.

With reference to FIG. 3, each processing unit of the OLT 10 according to the present embodiment will be described.
The PON port 11 is a circuit for exchanging frames with the ONU via the PON.
The receiving circuit 12 is a circuit for receiving an upstream frame from the ONU via the PON and the PON port 11.
A transmission circuit (system 0) 17A and a transmission circuit (system 1) 17B are provided for each preset transmission speed, and are respectively ONU (system 0) and ONU (system 1) via the PON port 11 and PON. ) To a downstream frame at the transmission rate. In the present invention, the 0 system indicates a transmission system with a transmission rate of 1 Gbps, and the 1 system indicates a transmission system with a transmission speed of 10 Gbps.

The SNI port (system 0) 19A and the SNI port 19B (system 1) are circuit units that are provided for each host device and exchange frames with the host device via the SNI.
The transmission / reception circuit (0 system) 18A and the transmission / reception circuit (1 system) 18B are provided for each higher-level device, that is, for each SNI. This is a circuit unit that transmits and receives frames between the network (0 system) NW1 and the carrier network (1 system) NW2.

The frame separation unit 13 transmits a frame addressed to the OLT 10 (control frame used for PON control) among the frames input from the reception circuit 12 to the control frame processing unit 14 and transmits other frames to the frame transfer processing unit. 20 is a processing unit that transmits data to 20.
The frame multiplexing unit (system 0) 16A multiplexes the downlink frame addressed to the ONU (system 0) from the frame transfer processing unit 20 and the control frame addressed to the ONU (system 0) from the control frame processing unit 14 in a time division manner. And a processing unit that transmits to the transmission circuit (system 0) 17A.
The frame multiplexing unit (system 1) 16B multiplexes the downstream frame addressed to the ONU (system 1) from the frame transfer processing unit 20 and the control frame addressed to the ONU (system 1) from the control frame processing unit 14 in a time division manner. And a processing unit that transmits to the transmission circuit (system 1) 17B.

  Based on the SNI selection information corresponding to the LLID of the upstream frame acquired from the LLID table 23, the frame transfer processing unit 20 receives the upstream frame received by the reception circuit 12 and input from the frame separation unit 13 from the transmission / reception circuit 18A. , 18B (0 system or 1 system), and the downstream frame received by the transmission / reception circuits 18A, 18B is a downstream output corresponding to the destination MAC address of the downstream frame acquired from the MAC address search table 27 This is a processing unit that performs transfer processing to either of the frame multiplexing units 16A and 16B (0 system or 1 system) based on the pre-selection information.

The control frame processing unit 14 is a processing unit that performs processing related to PON control such as discovery processing (Discovery process) for automatically assigning LLIDs to each ONU and arbitration of upstream signals (signals addressed to the OLT from the ONUs). .
The bandwidth allocation processing unit 15 allocates bandwidth (transmission start time and transmission data amount) to the ONU and manages the PON-IF port information transferred from the control frame processing unit 14 according to the request from the control frame processing unit 14. It is a processing part to perform.

[Operation of First Embodiment]
Next, the frame transfer process of the OLT 10 according to the present embodiment will be described in detail with reference to FIGS. FIG. 4 is a block diagram illustrating a configuration example of the frame transfer processing unit. FIG. 5 is a configuration example of the MAC address search table. FIG. 6 is a flowchart showing a procedure for determining a downlink frame output destination. FIG. 7 is a configuration example of the LLID table. FIG. 8 is a flowchart showing an upstream frame output destination SNI determination procedure.

First, the operation in which the frame transfer processing unit 20 determines the output destination of the downstream frame will be described.
The frame transfer processing unit 20 determines from which transmission circuit 17A, 17B the received downlink frame is transmitted, that is, to which downlink system having a different speed, the data is output as follows.

  The frame transfer processing unit 20 includes a MAC address search table 27 shown in FIG. In the MAC address search table 27, downlink output destination selection information, LLID, and entry valid / invalid are registered for each MAC address of the user apparatus connected to the ONU. The entry valid / invalid is information indicating validity / invalidity of the entry. “Entry invalid” indicates that “this entry is free” even if any value is described in the MAC address, downlink output destination selection information, and LLID of this entry.

  The downlink output destination determination units 34A and 34B are provided for each of the transmission / reception circuits 18A and 18B, and read the LLID and the downlink output destination selection information from the MAC address search table 27 based on the destination MAC address of the received downlink frame. The destination LLID and output destination of the downstream frame are determined by the procedure shown in FIG. The information of the determined LLID is given as a destination LLID to the LLID giving unit (0 system) 32A or the LLID giving unit (1 system) 32B, which is a corresponding system.

  In the downlink output destination determination procedure of the downlink frame in FIG. 6, the downlink output destination determination units 34A and 34B first, based on the entry validity / invalidity of the received destination MAC address of the downlink frame in the MAC address search table 27, It is confirmed whether or not the destination MAC address is registered in the MAC address search table 27 (step 100).

Here, when the “valid” state is set as the entry valid / invalid, and the destination MAC address is registered (step 100: YES), the downlink output destination determination units 34A and 34B determine the MAC address search table 27. The LLID corresponding to the destination MAC address is acquired from the ID and specified as the destination LLID of the downstream frame (step 101).
Subsequently, the downlink output destination determination units 34A and 34B acquire the downlink output destination selection information corresponding to the destination MAC address from the MAC address search table 27, and specify the output system of the downlink frame (step 102). A series of processing ends.

  On the other hand, if the MAC address field does not match the destination MAC address in any entry for which “valid” status is set as entry valid / invalid (step 100: NO), the downlink output destination determination units 34A and 34B The discard of the downlink frame is determined (step 103), and the series of processes is terminated.

In parallel with the downlink output destination determination procedure of the downlink frame, the downlink latency absorbing units 31A and 31B provided for the transmission / reception circuits 18A and 18B add a delay to the received downlink frame, and the downlink output destination The latency due to the downlink output destination determination process in the determination units 34A and 34B is absorbed.
The LLID assigning units 32A and 32B are provided for the transmission / reception circuits 18A and 18B, respectively, and assign the destination LLID to the downlink frames from the downlink latency absorbing units 31A and 31B according to the LLID determined by the downlink output destination determining units 34A and 34B. To do.

  The downlink output destination control units 33A and 33B are provided for each of the transmission / reception circuits 18A and 18B, and in accordance with the downlink output destination selection information determined by the downlink output destination determination units 34A and 34B, the corresponding 0-system downlink output timing adjustment unit The downlink frames from the LLID adding units 32A and 32B are transferred to the transmission circuits 17A and 17B corresponding to the downlink output destination selection information via the 36A or 1-system downlink output timing adjustment unit 36B.

The downlink output timing adjustment units 36A and 36B are provided for each transmission rate (transmission system), and adjust the output order of each downlink frame based on the priority determined by the PCP included in the downlink frame. Then, the downstream frame is transferred to the corresponding transmission circuits 17A and 17B via the corresponding frame multiplexing units 16A and 16B. For example, in a system in which 10G-ONU and 1G-ONU coexist, 10G (802.3av specification) output may be specified for 10G-ONU, and 1G (802.3ah specification) output may be specified for 1G-ONU.
When the downlink output destination determination units 34A and 34B determine that the packet is to be discarded, the downlink output destination control units 33A and 33B perform a process of discarding the downlink frame.

  When a downlink frame is transferred from the 0-system downlink output destination control unit 33A to the 1-system downlink output timing adjustment unit 36A, or from the 1-system downlink output destination control unit 33B to the 1-system downlink output timing adjustment unit 36B An example of a case where a downstream frame is transferred includes a system in which GE-PON and 10G-EPON coexist. In the present invention, the 0 system indicates a transmission system with a transmission rate of 1 Gbps, and the 1 system indicates a transmission system with a transmission speed of 10 Gbps.

In such a case, when the destination user apparatus of the downlink frame having a transmission rate of 10 Gbps input from the SNI port (system 1) is under the ONU for GE-PON, the GE having the transmission rate of 1 Gbps is transmitted from the PON port 11 in the OLT 10. -It is necessary to output as a PON frame.
For this purpose, the frame transfer processing unit 20 needs to output the downlink frame received from the 1 system from the 0 system. Such a technique is necessary in the transition period from GE-PON to 10G-EPON.

  For the MAC address search table 27, the MAC address registration unit 26 acquires the transmission source MAC address and LLID from the received upstream frame, and obtains the LLID and the downlink output destination selection information previously associated with the LLID. It is registered in the MAC address search table 27 in association with the source MAC address. For the downlink output destination selection information, for example, the downlink output destination selection information of the ONU may be acquired by a control frame notified from the ONU at the start of communication.

  In the configuration of this embodiment, the value of the MAC address search table 27 is set by software that controls and manages the OLT 10. Specifically, when the MAC address registration unit 26 sets information to be registered in the MAC address search table 27 as shown in FIG. 5 in a register and sets a MAC address setting request flag, the software Information is written into the MAC address search table 27 and a MAC address setting completion flag is set. In this way, for each LLID, the destination MAC address of the downstream frame and the downstream output destination selection information are managed, and necessary information is registered in the MAC address search table 27.

Next, the operation in which the frame transfer processing unit 20 determines the output destination of the upstream frame will be described.
If the upstream frame received at the PON port 11 is not a PON control frame, the frame transfer processing unit 20 determines to which provider network NW the received upstream frame is to be output as follows.

The frame transfer processing unit 20 includes an LLID table 23 as shown in FIG. In the LLID table 23, entry valid / invalid and SNI selection information are registered for each LLID of the ONU. The entry valid / invalid is information indicating validity / invalidity of the entry, that is, registered / unregistered of the LLID.
The output destination SNI determination unit 22 reads the SNI selection information from the LLID table 23 based on the LLID of the upstream frame, determines the output destination SNI by the procedure of FIG. 8, and determines the SNI selection information as the upstream output destination control unit. 24.

In the uplink frame output destination SNI determination procedure in FIG. 8, the output destination SNI determination unit 22 first determines that the LLID is included in the LLID table 23 based on the LLID entry validity / invalidity of the received uplink frame. (Step 110).
Here, when the “valid” state is set as the entry valid / invalid, that is, when the LLID is registered (step 110: YES), the output destination SNI determination unit 22 reads the LLID from the LLID table 23. The SNI selection information corresponding to is acquired and specified as the output destination of the downlink frame (step 111), and the series of processing ends.

  On the other hand, when the “invalid” state is set as the entry valid / invalid, that is, when the LLID of the received uplink frame is not registered in the LLID table 23 (step 110: NO), the output destination SNI determining unit 22 Then, the discard of the uplink frame is determined (step 112), and the series of processing ends.

In parallel with such an upstream frame output destination SNI determination procedure, the upstream latency absorption unit 21 adds a delay to the received upstream frame and absorbs the latency due to the output destination SNI determination process in the output destination SNI determination unit 22. To do.
The uplink output destination control unit 24 transfers the uplink frame from the uplink latency absorbing unit 21 to the corresponding uplink output timing adjustment units 25A and 25B according to the SNI selection information determined by the output destination SNI determination unit 22.

Upstream output timing adjustment units 25A and 25B are provided for each of the transmission / reception circuits 18A and 18B, and adjust the output order of each upstream frame based on the priority determined by the PCP included in each upstream frame. The upstream frame from the upstream output destination control unit 24 is transferred to the corresponding transmission / reception circuits 18A and 18B.
When frame discard is notified from the output destination SNI determination unit 22, the uplink output destination control unit 24 performs discard processing on the uplink frame.

  The value of the LLID table 23 is determined by the network NW1, NW2 (in FIG. 3, the carrier NW (0 system) by the external hardware or software (not shown in FIG. 3) during ONU registration in the control frame processing unit 14. ), It is determined and determined whether to connect to the operator NW (system 1). For example, in a system in which 10G-ONU and 1G-ONU are mixed and one of the SNIs is for 10G-Ethernet, and the other is for 1G-Ethernet, the 10G-ONU SNI for 10G-Ethernet, 1G- For the ONU, an SNI for 1G-Ethernet can be specified.

  In the downstream processing, it is necessary to process the frames input from the two transmission / reception circuits 18A and 18B in parallel. However, as shown in the configuration of FIG. The frame input throughput can be used up to the upper limit. At this time, since the upper limit of throughput when the 10G output is 802.3av specification is about 8.7 Gbps, the upper limit of the throughput of the SNI input for 10G output in that case is about 8.7 Gbps.

[Effect of the first embodiment]
As described above, in this embodiment, the LLID of the ONU and the downlink output destination selection information are registered in the MAC address search table 27 for each MAC address of the user apparatus connected to the ONU, and the downlink frame is transmitted from the host apparatus. Is received from the MAC address search table 27 by the frame transfer processing unit 20 in parallel for each input SNI port, the LLID and the downlink output destination selection information corresponding to the destination MAC address of the downlink frame. It is a thing.

As in the first prior art described above, when determining the transmission rate after determining the destination LLID of the downstream frame, a circuit for reading a table for managing the downstream transmission speed for each LLID in addition to the MAC address search table 27. This increases the circuit scale of the OLT.
According to the present embodiment, the destination LLID and the downlink output destination selection information (transmission speed) of the downlink frame can be specified only by reading (searching) from the MAC address search table 27. Therefore, the circuit scale of the OLT can be reduced. The output system of the downstream frame can be specified with almost no increase.

  Further, in the present embodiment, when the SLI selection information corresponding to the LLID is registered for each LLID of the ONU in the LLID table 23 and an upstream frame is received from the ONU, the frame transfer processing unit 20 The SNI selection information corresponding to the LLID of the upstream frame is obtained from the LLID table 23.

As a result, when the OLT is connected to a plurality of higher-level devices via the SNI provided for each higher-level device, an upstream frame received from any ONU connected to the PON system Can be transferred to the device. In addition, it is possible to process downstream frames input via a plurality of SNI ports in parallel for each input SNI port and transfer them to the destination ONU.
Therefore, one OLT having a port for each SNI between each ONU of the PON system and each host device, and further each carrier network, without a switch between a plurality of OLT SNIs. The frame can be transferred. For this reason, it is possible to avoid sharing the downstream band of the switch among the higher-level devices, and to avoid restrictions on the downstream bandwidth that can be used by the individual higher-level devices.

  In this embodiment, in a system in which 10G-ONU and 1G-ONU are mixed, when one of the SNIs is for 10G-Ethernet and the other is for 1G-Ethernet, the 10G-ONU is the SNI for 10G-Ethernet. For 1G-ONU, an SNI for 1G-Ethernet can be used.

  In this case, all frames input from the 10G-Ethernet SNI are destined for the 10G-ONU, and all frames input from the 1G-Ethernet SNI are destined for the 1G-ONU. The downlink transfer capability (transmission speed) in the section can be used up to the upper limit. As a result, unlike the conventional configuration of FIG. 24, the downstream band is not shared by the two higher-level devices.

  When the downlink output addressed to 10G-ONU is 802.3av specification, the upper limit of the downlink throughput in the PON section is about 8.7 Gbps, so the upper limit of the SNI input throughput for 10G-ONU in that case is about 8.7 Gbps. Downstream bandwidth limitation is necessary in the host device for 10G-ONU. However, this band limitation is the same even when only one host device for 10G-ONU is connected, and the effectiveness of the present invention is not denied.

If an OLT equipped with only one 10G-Ethernet SNI is configured in the prior art, the upper limit of downlink throughput when the 802.3av specification and the 802.3ah specification are mixed is the same as that of the present invention. Although 7 Gbps + 1 Gbps = about 9.7 Gbps, a switch or the like is required to connect to a plurality of higher-level devices.
Also, in this embodiment, if the specification of the downlink output addressed to 10G-ONU is changed to a specification that enables throughput of 10 Gbps instead of 802.3av specification, 10G-ONU and 1G-ONU are mixed The maximum downstream downlink throughput is 10 Gbps + 1 Gbps = 11 Gbps, and no downstream bandwidth limitation is required in the host device.

  When the frame transfer processing unit 20 is configured as shown in FIG. 4, it is possible to use a 10G-Ethernet SNI as the 1G-ONU SNI. However, in this case, it is necessary for the host device to limit the downstream band to 1 Gbps or less. Conversely, a 1G-Ethernet SNI can be used as a 10G-ONU SNI. In this case, the downlink transfer capability in the PON section cannot be used up to the upper limit.

  Moreover, although this Embodiment demonstrated as an example the system in which 10G-ONU and 1G-ONU were mixed, it is not limited to this. For example, the ONU to be accommodated is only a 10G-ONU, but the present invention can also be applied when connecting to different networks for each ONU. The OLT in this case may be equipped with a plurality of 10G-Ethernet SNIs and a plurality of downstream PON outputs equivalent to the 802.3av specification. However, the downstream wavelength may be changed for each downstream output port, and may be changed for each higher-level network to which the WDM filter mounted on the ONU is connected as necessary.

  In the present embodiment, the MAC address registration unit 26 acquires the transmission source MAC address and the LLID from the received upstream frame, and the LLID and the downlink output destination selection information corresponding to the LLID are converted into the transmission source MAC. Since it is registered in the MAC address search table 27 in association with the address, the MAC address search table 27 can be registered and updated based on the received upstream frame.

[Second Embodiment]
Next, the OLT 10 according to the second embodiment of the present invention will be described with reference to FIG. FIG. 9 is a block diagram illustrating a configuration of the OLT according to the second embodiment.
Compared to the first embodiment, an upstream input unit 12A is added to the OLT 10 according to the present embodiment.

In the present embodiment, in addition to the functions described in the first embodiment, the bandwidth allocation processing unit 15 is configured to update the scheduled upstream frame in accordance with the upstream frame timing previously allocated by the bandwidth allocation processing unit 15. It has a function of reading the downlink output destination selection information corresponding to the LLID from the PON-IF port information registered in advance in the bandwidth allocation processing unit 15 and instructing the downlink input destination selection information to the uplink input unit 12A. .
The uplink input unit 12A is a processing unit that inserts the downlink output destination selection information instructed by the band allocation processing unit 15 into the preamble of the uplink frame.

The MAC address registration unit 26 (see FIG. 4) acquires the transmission source MAC address, the LLID, and the downlink output destination selection information from the uplink frame from the uplink input unit 12A, and obtains the LLID and the downlink output destination selection information. It has a function of registering in the MAC address search table 27 in association with the source MAC address.
Other configurations according to the present embodiment are the same as those in the first embodiment, and a detailed description thereof is omitted here.

[Operation of Second Embodiment]
The band allocation processing unit 15 reads out downlink output destination selection information corresponding to the LLID of the scheduled uplink frame from the PON-IF port information in accordance with the reception timing of the uplink frame allocated in advance, and this downlink output destination selection information To the upstream input unit 12A. As the downlink output destination selection information, for example, the downlink output destination selection information of the ONU is acquired by a control frame notified from the ONU at the start of communication.

  At this time, if the LLID of the uplink frame is assigned to 1G-ONU (uplink speed is 1G, downlink speed is 1G), “0 system” is indicated as downlink output destination selection information, and the LLID of the uplink frame is When 10G-ONU (uplink speed is 10G, downlink speed is 10G), “1 system” is instructed as downlink output destination selection information. When the LLID of the upstream frame is assigned to an asymmetric ONU (upstream speed is 1G and downstream speed is 10G), “1 system” is instructed as downstream output destination selection information.

The uplink input unit 12A inserts the downlink output destination selection information instructed from the band allocation processing unit 15 into the preamble of the uplink frame. FIG. 10 is a configuration example of an upstream frame output from the upstream input unit 12A. The difference from the frame transmitted in the PON section shown in FIG. 2 is that the downlink output destination selection information is inserted in the preamble.
For example, if the instruction from the bandwidth allocation processing unit 15 is “0 system”, the upstream input unit 12A inserts “0” into the downstream output destination selection information of the preamble of the upstream frame, If the instruction is “1 system”, “1” is inserted into the downlink output destination selection information of the preamble of the uplink frame.

In the OLT configuration according to the present embodiment, it is possible to automatically set the value of the MAC address search table 27 in the frame transfer processing unit 20 when receiving an upstream frame. Hereinafter, a method in which the frame transfer processing unit 20 automatically registers the transmission source MAC address and the output destination selection information of the received upstream frame will be described. FIG. 11 is a flowchart showing the MAC address registration process.
If the received upstream frame is not a PON control frame, the MAC address registration unit 26 performs the MAC address registration process of FIG. 11 based on the transmission source MAC address of the upstream frame.

  First, the MAC address registration unit 26 searches the MAC address search table 27 based on the source MAC address of the upstream frame (step 200), and when the source MAC address is already registered in the MAC address search table 27 ( (Step 200: YES), the downlink output destination selection information and the LLID corresponding to the MAC address are updated (Step 201), and the series of processing ends. Note that step 201 may not be executed and not updated.

  As shown in FIG. 10, the downlink output destination selection information registered in the MAC address search table 27 is acquired by the MAC address registration unit 26 as the downlink output destination selection information inserted in the preamble of the uplink frame by the uplink input unit 12A. It is a thing. Further, the LLID is obtained by the MAC address registration unit 26, which has been previously inserted in the preamble of the upstream frame.

On the other hand, when the MAC address is not registered in the MAC address search table 27 (step 200: NO), the MAC address registration unit 26 checks whether there is a vacancy in the MAC address search table 27 (step 202). “There is a vacancy” indicates that there is an entry in which the “invalid” state is set as the entry valid / invalid.
If there is a vacancy (step 202: YES), the downlink output destination selection information and the LLID are newly registered in the vacant entry in association with the MAC address (step 203), and the series of processing ends. If there is no space (step 202: NO), the series of processes is terminated.

[Effect of the second embodiment]
As described above, in the present embodiment, the uplink input unit 12A gives the downlink output destination selection information regarding the transmission source ONU of the received uplink frame to the uplink frame, and the MAC address registration unit 26 receives the information from the uplink input unit 12A. The source MAC address, LLID, and downlink output destination selection information are acquired from the upstream frame, and the LLID and downlink output destination selection information are associated with the source MAC address and registered in the MAC address search table 27. It is a thing.

As a result, the MAC address registration unit 26 automatically registers the MAC address, LLID, and downlink output selection information in the MAC address search table 27, including the case of an asymmetric ONU (uplink speed is 1G and downlink speed is 10G). be able to.
In addition, since the downlink output destination selection information is notified to the MAC address registration unit 26 using the uplink frame, at the same time, in the same manner as the transmission source MAC address and LLID registered in the MAC address search table 27, The MAC address registration unit 26 can acquire the downlink output destination selection information at the same timing. Thereby, it is not necessary to add a circuit or control for acquiring the downlink output destination selection information in synchronization with the transmission source MAC address or LLID, and the downlink output destination selection information can be notified with an extremely simple configuration.

  Note that the configuration of the present embodiment requires the addition of an upstream input unit 12A that inserts downstream output destination selection information in upstream processing as compared to the configuration of the first embodiment. At this time, the downstream output destination selection information (corresponding to the transmission rate of the control frame called a Gate frame) is obtained from the bandwidth allocation processing unit 15 that performs upstream bandwidth allocation, so that the downstream output destination selection information is easily included in the preamble of the upstream frame. Can be inserted.

[Third Embodiment]
Next, an OLT 10 according to a third embodiment of the present invention will be described.
In the present embodiment, the MAC address registration unit 26 of the OLT 10 confirms the reception history of registered MAC addresses at regular intervals, and uses the MAC address search table 27 to register registered MAC addresses that have no reception history within a certain period. A means for invalidation (aging process) is added. The period of the aging process is “aging period”, and the timer for counting the aging period is “aging timer”.

  FIG. 12 shows another configuration example of the MAC address search table. Compared with FIG. 5 described above, an item “Reception Status after Aging” is added. “Reception status after aging” is information indicating whether or not a frame of the corresponding MAC address has been received from the previous aging process to the present.

  FIG. 13 is another flowchart showing the MAC address registration procedure. This MAC address registration procedure is such that the reception status after aging corresponding to the MAC address is set to “with reception” at the end of the MAC address registration procedure of FIG. 11 (step 304). Thereby, every time the MAC address is newly registered or registered and updated, the reception status after aging becomes “received”.

FIG. 14 is a flowchart showing an aging process procedure. The MAC address registration unit 26 executes the aging process procedure of FIG. 14 at regular intervals.
First, the MAC address registration unit 26 selects one entry that is not currently processed from the MAC address search table 27 (step 310), and confirms whether the entry of this selected entry is set to the “valid” state (step 310). 311). If the selected entry is in the “valid” state (step 311: YES), it is confirmed whether the reception status after aging of the selected entry is set to “received” (step 312).

  If “Received” is set (step 312: YES), the reception status after aging of the selected entry is set to “not received” (step 313), and it is confirmed whether all entries have been processed. If there is an unprocessed entry (step 315: NO), the process returns to step 310. If all entries have been processed (step 315: YES), the series of processes ends.

On the other hand, if the reception status after aging of the selected entry is set to “no reception” (step 312: NO), the entry of the selected entry is set to an “invalid” state indicating that it is unused (step 314). ), The process proceeds to step 315.
If the entry of the selected entry is in the “invalid” state at step 311 (step 311: NO), the process proceeds to step 315.

FIG. 15 is a time chart showing the transition of information stored in a certain entry in the MAC address search table.
At time T11 within the aging period T from time T1 to time T2, when the OLT 10 receives an upstream frame having an unregistered source MAC address, the source MAC address is newly registered in an empty entry, The entry is set to the “valid” state and “received”, and is set to “not received” in the next aging process at time T2.

  Subsequently, when an uplink frame having this source MAC address is received again at time T12 within the aging period T from time T2 to time T3, the same MAC address is registered and updated in the entry, and the “valid” state and “reception” “Yes”, and “No reception” is set in the next aging process at time T3.

  In this way, if the frame having this source MAC address is not received within the aging period T from the time T3 to the time T4 after being set to the “valid” state and “no reception”, the time T4 In the next aging process at, the entry is set to the “invalid” state.

Therefore, the entry remains in the “valid” state even if “no reception” is set in the aging process at times T2 and T3, so that the source MAC address continues in the MAC address search table 27 until time T4. However, at time T4, the state is set to “invalid”. The entry being set to the “invalid” state means that this MAC address is deleted from the MAC address search table 27 and this entry is free (from the table when the entry becomes invalid). It is considered deleted).
Another MAC address can be newly registered in the storage area where the entry is set to the invalid state.

[Effect of the third embodiment]
As described above, in the present embodiment, the MAC address registration unit 26 registers the reception status regarding the transmission source MAC address of the uplink frame in the MAC address search table 27 for each received uplink frame. The reception status of each MAC address registered in the above is inspected, and among these MAC addresses, MAC addresses that have not been confirmed to be received within a certain period are set to an invalid state.

  As a result, if a frame having the same source MAC address is not received before the aging process is performed twice after the frame having a certain source MAC address is received last, the source MAC address is invalid thereafter. Set to state. Accordingly, another MAC address can be newly registered in the storage area in which the registration information is invalid, so that the MAC address search table 27 having a limited size (entry) can be used effectively.

For example, an attempt to prepare an entry for all values of MAC address of 48bit can take, 2 ⁴⁸ entries are required, the MAC address lookup table 27 becomes very large, the circuit scale is also increased. Therefore, a small MAC address search table 27 is prepared, and MAC addresses that are no longer used are deleted from the MAC address search table 27 and stored in empty entries when newly registering, thereby increasing the circuit scale. Can be suppressed. In this way, in the method of searching for a free entry and storing a newly registered MAC address, the MAC addresses are registered in an irregular manner.

[Fourth Embodiment]
Next, an OLT 10 according to a fourth embodiment of the present invention will be described with reference to FIGS. 16 and 17. FIG. 16 is a block diagram illustrating a configuration of a frame transfer processing unit according to the fourth embodiment. FIG. 17 is a configuration example of the VID table.
Compared to the first embodiment, a VID table 35 is added to the frame transfer processing unit 20 according to the present embodiment.

  In the present embodiment, the frame transfer processing unit 20 transmits the received downlink frame from which transmission circuit 17A, 17B based on the registered contents of the MAC address search table 27 or the VID table 35, that is, which has a different speed. Decide whether to output to the downstream system. Hereinafter, an operation in which the frame transfer processing unit 20 determines the output destination of the downlink frame will be described.

  The downlink output destination determination units 34A and 34B perform frame transfer processing based on the destination MAC address or VID of the received downlink frame. At this time, as shown in FIG. 5 described above, the downlink output destination selection information and the LLID are registered in the MAC address search table 27 for each MAC address. Further, as shown in FIG. 17, the LLID and the downlink output destination selection information are registered in advance in the VID table 35 for each VID. VID (VLAN Identifier) is a value that specifies the VLAN to which the downlink frame belongs.

The downlink output destination determination units 34A and 34B read the LLID and the downlink output destination selection information and determine the LLID and the output destination by the following method A or method B.
Method A: The LLID and the downlink output destination selection information are read from the MAC address search table 27 based on the destination MAC address of the received downlink frame.
Method B: The LLID and the downlink output destination selection information are read from the VID table 35 based on the received downlink frame VID.

  Information on the determined LLID is given to the LLID assigning units 32A and 32B as the destination LLID of the downstream frame. Further, the determined output destination information is given to the downlink output destination control units 33A and 33B as downlink output destination information.

FIG. 18 is a flowchart showing a procedure for determining an output destination of a downstream frame.
First, the downlink output destination determination units 34A and 34B confirm whether or not to use the MAC address search table 27 by the method A based on the preset processing method selection information (step 400).

  Here, when the method A is designated (step 400: YES), the downlink output destination determination units 34A and 34B make the entry of the destination MAC address of the received downlink frame valid / invalid in the MAC address search table 27. Based on this, it is confirmed whether the destination MAC address is registered in the MAC address search table 27 (step 401).

  Here, when the “valid” state is set as the entry valid / invalid, and the destination MAC address is registered (step 401: YES), the downlink output destination determination units 34A and 34B perform the MAC address search table 27. The LLID retrieved from is determined as the destination LLID of the downlink frame (step 402), the output system of the downlink frame is determined based on the retrieved downlink output destination selection information (step 403), and the series of processing ends.

  On the other hand, if the MAC address field does not match the destination MAC address in any entry that is set as “valid” as entry valid / invalid (step 401: NO), the downlink output destination determination units 34A and 34B The discard of the downlink frame is determined (step 421), and the series of processes is terminated.

In step 400, when the method B using the VID table 35 is designated (step 400: NO), the downlink output destination determination units 34A and 34B confirm whether the received downlink frame includes a VLAN tag. (Step 410).
Here, when the VLAN tag is included (step 410: YES), the downlink output destination determination units 34A and 34B, based on the validity / invalidity of the VID entry of the received downlink frame in the VID table 35, It is confirmed whether or not the VID is registered in the VID table 35 (step 411).

  Here, when the “valid” state is set as the entry valid / invalid, that is, when the VID is registered (step 411: YES), the downlink output destination determination units 34A and 34B The LLID corresponding to the VID is acquired and specified as the destination LLID of the downlink frame (step 412), the downlink output destination selection information corresponding to the VID is acquired from the VID table 35, and the output system of the downlink frame is determined. Specify (step 413), and the series of processing ends.

On the other hand, when the “invalid” state is set as the entry valid / invalid, that is, when the VID of the received downlink frame is not registered in the VID table 35 (step 411: NO), the downlink output destination determination unit 34A, 34B decides to discard the downlink frame (step 421), and ends the series of processes.
In step 410, if a VLAN tag is not included (step 410: NO), it is confirmed whether an untagged frame is permitted (step 420). If it is permitted (step 420: YES), step 401 is performed. If it is not permitted (step 420: NO), the process proceeds to step 421.

  Except for the downlink output destination determination processing of the downlink output destination determination units 34A and 34B and the VID table 35, the operation is the same as that of the first embodiment.

  The values in the VID table 35 are determined and set by the external hardware or software (not shown in FIG. 16) when the ONU is registered in the control frame processing unit 14.

[Extended embodiment]
The present invention has been described above with reference to the embodiments, but the present invention is not limited to the above embodiments. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention. In addition, each embodiment can be implemented in any combination within a consistent range.

  DESCRIPTION OF SYMBOLS 100 ... PON system, 10 ... OLT, 11 ... PON port, 12 ... Receiver circuit, 12A ... Uplink input part, 13 ... Frame separation part, 14 ... Control frame processing part, 15 ... Band allocation processing part, 16A ... Frame multiplexing part (0 system), 16B ... Frame multiplexing unit (1 system), 17A ... Transmission circuit (0 system), 17B ... Transmission circuit (1 system), 18A ... Transmission / reception circuit (0 system), 18B ... Transmission / reception circuit (1 system) , 19A ... SNI port (0 system), 19B ... SNI port (1 system), 20 ... frame transfer processing unit, 21 ... uplink latency absorption unit, 22 ... output destination SNI determination unit, 23 ... LLID table, 24 ... uplink output Prior control unit, 25A ... Uplink output timing adjustment unit (system 0), 25B ... Uplink output timing adjustment unit (system 1), 26 ... MAC address registration unit, 27 ... MAC address search table , 31A ... Downlink latency absorbing unit (system 0), 31B ... Downlink latency absorbing unit (system 1), 32A ... LLID adding unit (system 0), 32B ... LLID adding unit (system 1), 33A ... Downstream output destination control unit (0 system), 33B ... downlink output destination control unit (system 1), 34A ... downlink output destination determination unit (system 0), 34B ... downlink output destination determination unit (system 1), 35 ... VID table, 36A ... downlink output Timing adjustment unit (system 0), 36B... Downstream output timing adjustment unit (system 1).

Claims (8)

In addition to connecting to a plurality of ONUs via a PON, connecting to a plurality of higher-level devices via SNI (Service Node Interface) provided for each higher-level device, and frames exchanged between these ONUs and the higher-level devices are mutually connected. OLT to transfer to
A receiving circuit for receiving an upstream frame from the ONU via the PON;
A plurality of transmission circuits that are provided for each transmission rate set in advance, and transmit a downstream frame to the ONU at the transmission rate via the PON;
A plurality of transmission / reception circuits provided for each of the SNIs, for transmitting the uplink frame to the host device via the SNI and receiving the downlink frame from the host device via the SNI;
A frame transfer processing unit that transfers the uplink frame received by the reception circuit to the transmission / reception circuit, and transfers the downlink frame received by the transmission / reception circuit to the transmission circuit;
The frame transfer processing unit
For each individual LLID (Logical Link ID) in the ONU, an LLID table in which SNI selection information corresponding to the LLID is registered;
A MAC address search table in which the LLID of the ONU and downlink output destination selection information are registered for each individual MAC address in the user apparatus connected to the ONU,
The SNI selection information corresponding to the LLID of the uplink frame received by the reception circuit is acquired from the LLID table, and the uplink frame is transferred to the transmission / reception circuit corresponding to the SNI selection information in the transmission / reception circuit,
After acquiring the LLID and the downlink output destination selection information corresponding to the destination MAC address of the downlink frame received by the transmission / reception circuit from the MAC address search table, and adding the LLID to the downlink frame, OLT characterized by transferring to the transmission circuit corresponding to the downlink output destination selection information. The OLT according to claim 1,
The frame transfer processing unit
An output destination determination unit that acquires, from the LLID table, SNI selection information corresponding to the LLID of the uplink frame received by the reception circuit;
The OLT further comprising: an uplink output destination control unit that transfers the uplink frame to a transmission / reception circuit corresponding to the SNI selection information acquired by the output destination determination unit in the transmission / reception circuit. In the OLT according to claim 1 or 2,
The frame transfer processing unit
A plurality of downlink output destination determination units that are provided for each of the transmission / reception circuits and obtain LLID and downlink output destination selection information corresponding to the destination MAC address of the downlink frame received by the transceiver circuit from the MAC address search table; ,
A plurality of LLID provision units provided for each of the transmission / reception circuits, and configured to append the LLID acquired by the downlink output destination determination unit to the downlink frame received by the transmission / reception circuit;
A plurality of the transmission / reception circuits that transfer the downlink frame from the LLID adding unit to the transmission circuit corresponding to the downlink output destination selection information acquired by the downlink output destination determination unit among the transmission circuits. The OLT further includes a downstream output destination control unit. In the OLT according to any one of claims 1 to 3,
The frame transfer processing unit acquires a transmission source MAC address and LLID from the upstream frame received by the reception circuit, and transmits the LLID and downlink output destination selection information associated with the LLID in advance to the transmission source. The OLT further comprising a MAC address registration unit that registers the MAC address in the MAC address search table in association with the MAC address. The OLT according to claim 4, wherein
An uplink input unit that adds, to the uplink frame, downlink output destination selection information that is previously associated with the LLID of the uplink frame with respect to the uplink frame received by the reception circuit;
The MAC address registration unit acquires the transmission source MAC address, the LLID, and the downlink output destination selection information from the uplink frame output from the uplink input unit, and registers them in the MAC address search table OLT characterized by that. In the OLT according to claim 4 or 5,
The MAC address registration unit
When registering the LLID and the downlink output destination selection information, register in the MAC address search table including the reception status regarding the source MAC address,
For each fixed aging period, the reception status of each MAC address registered in the MAC address search table is inspected, and MAC addresses that have not been confirmed to be received within the aging period are invalidated among these MAC addresses. OLT characterized by setting. In the OLT according to any one of claims 1 to 6,
The frame transfer processing unit
For each VID (VLAN Identifier) for identifying the VLAN to which the downlink frame belongs, further includes a VID table in which LLID and downlink output destination selection information related to the downlink frame are registered,
The LLID and the downlink output destination selection information regarding the downlink frame received by the transceiver circuit are acquired from the MAC address search table based on the destination MAC address of the downlink frame, or the VID table based on the VID of the downlink frame OLT characterized by being acquired from. A plurality of ONUs are connected via a PON and connected to a plurality of higher-level devices via an SNI (Service Node Interface) provided for each higher-level device, and frames exchanged between these ONUs and the higher-level devices are mutually connected. A frame transfer method used in the OLT for transfer processing to
For each LLID (Logical Link ID) in the ONU, storing SNI selection information corresponding to the LLID in an LLID table;
Storing the LLID and downlink output destination selection information of the ONU in a MAC address search table for each individual MAC address in the user apparatus connected to the ONU;
The SNI selection information corresponding to the LLID of the upstream frame received from the ONU via the PON is acquired from the LLID table, and the frame is provided for each SNI and transmitted / received to / from the host device via the SNI. A step of transferring the uplink frame to a transmission / reception circuit corresponding to the SNI selection information,
After acquiring the LLID and the downlink output destination selection information corresponding to the destination MAC address of the downlink frame received by the transmission / reception circuit from the MAC address search table, and adding the LLID to the downlink frame, the transmission rate is set in advance. And a step of transferring a downlink frame to the ONU to a transmission circuit corresponding to the downlink output destination selection information among a plurality of transmission circuits that transmit the downlink frame to the ONU at the transmission rate via the PON. Frame transfer method.

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