The present application claims priority from Japanese patent application JP 2010-259454 filed on Nov. 19, 2010, the contents of which are hereby incorporated by reference into this application.
1. Field of the Invention
The present invention relates to a passive optical network system, a station side apparatus and a power consumption control method, and more particularly to a passive optical network system, a station side apparatus and a power consumption control method for realizing the power saving of the station side apparatus and home side apparatuses in the Passive Optical Network (hereinafter referred to as PON) System constituting an optical access network, and especially reducing the power consumption of the system by switching the operation of the PON system based on the result of detecting the unused condition of the user accommodated in the PON.
2. Description of the Related Art
The PON system is an optical access system in which one optical fiber is divided via an optical splitter that is a passive type device to draw into plural subscriber homes. The PON system is generally composed of an Optical Line Terminal (hereinafter referred to as an OLT) equipment installed on the station side of a carrier, an Optical Network Unit (hereinafter referred to as an ONU) that is a home side apparatus installed at the subscriber's home or subscriber building, the optical splitter and the optical fiber. In a section from the OLT within the station to a user living area, one optical fiber is shared among plural subscribers, and the optical fiber is distributed into the subscriber's homes via the optical splitter not requiring power in each user living area. In this way, the PON system is suitable for inexpensively providing an internet connection service or a company oriented private line service to users distributed over a service area, because the equipment can be shared among the plural subscribers by multiplexing plural subscriber signals to make the one-to-multiple connection. Examples of the PON system include a GE-PON system as standardized in an Institute of Electrical and Electronic Engineers (IEEE) 802.3ah, and a 10G-EPON system as standardized in the IEEE802.3av. In recent years, there has been a growing interest worldwide in the environmental problems, whereby the energy saving measures are an essential subject for companies and homes, and in the field of communication apparatus, a power saving function and a function of reducing a load on the apparatus when not in use have been examined.
As the background technology in this technical field, there is JP-A-2008-113193 (patent document 1). This official gazette describes that “a subscriber side apparatus for suppressing the power consumption efficiently can be obtained by monitoring the connection state of the ONU with the OLT or Terminal Equipment (TE) and setting the functional block of the ONU in a low power consumption mode”. Also, there is JP-A-2006-115143 (patent document 2). This official gazette describes that “since the logical link is established for each application as needed, it is unnecessary to waste the processing power of each optical terminating device on the center side and user side to maintain the logical link not in use”.
In the above method of patent document 1, there is a problem that since the ONU transits to a low power consumption mode only when a User Network Interface (UNI) link state of the ONU or the optical link state on the PON side is down, the power consumption can not be reduced at all in a state where the UNI link or optical link is up. Also, the power consumption reduction object is only the ONUs in the PON system. Also, when the hardware is placed in the low power consumption mode, a restoration processing time for resuming the communication operation of user frame after releasing the mode is required, but no consideration is taken for the continuity of service in this point.
In an example of patent document 2, the logical link itself between OLT and ONU is disconnected in detecting a unused state for the user application. With this method, in transiting from the unused state to the use state, an initiation determination process of the application and a Discovery sequence process for establishing the logical link with the OLT again and registering the ONU take a lot of time. Accordingly, there is a problem that the communication cannot be started in an instant.
In the light of the above-mentioned problems, it is an object of the invention to provide a passive optical network system, a station side apparatus and a power consumption control method capable of reducing the operation frequency of electronic circuits and optical devices in both the OLT and the ONT in an unused state by a user and reducing the power consumption while maintaining the continuity of service. Also, it is another object of the invention to provide user usage state management means for determining the use situation of the user accommodated in the PON system in the station side apparatus, and suppress a transmitting and receiving process for unnecessary control frames at the time of making the user unused determination in the state where the logical link between OLT and ONU is maintained.
A PON system according to this invention has a station side apparatus (OLT) and plural home side apparatuses (ONUs), which are connected via an optical fiber network having an optical splitter, in which the station side apparatus includes a Dynamic Bandwidth Allocation (DBA) processing part for controlling the frame transfer in the direction from ONU to OLT, a transfer database part for managing the destination of user frame transfer from OLT to the plural ONUs, a statistical counter part for counting the transfer data amount of each user, and a user usage state management part for managing the user use situation.
The user usage state management part determines the user usage situation based on the state monitoring result of one or all of the DBA processing part, the transfer database part and the statistical counter part, switches the operation of the DBA control part depending on the use situation and adjusts the control frame amount between OLT and GNU.
In this invention, by determining that the user is in the unused state depending on the presence or absence of user traffic, and reducing the DBA control frame amount for use in the user frame transfer between ONU and OLT when not in use, it is possible to reduce the operation frequency of the electronic circuits and the optical devices for both of the OLT and ONU and the power consumption even in a state where the user can use the network, such as when various kinds of terminal is being connected to the ONU and the power of the terminal is on.
According to the first solving means of this invention, there is provided a passive optical network system comprising a station side apparatus and a plurality of home side apparatuses, in which the station side apparatus allocates uplink bandwidth to each of home side apparatuses by transmitting and receiving a control packets via logical links between the station side apparatus and each of home side apparatuses and provides allocated uplink bandwidth to the home side apparatuses, wherein
the station side apparatus comprises:
a transfer database for storing transfer information for specifying a destination of frame transfer from the station side apparatus to the plurality of home side apparatuses for each logical link;
a transfer processing part for performing a transfer process of a frame;
a statistical counter for counting a transfer data amount for each logical link; and
a usage state management part for determining a logical link for which the transfer information is not registered in the transfer database and/or a logical link for which a count value of the statistical counter is not increased within a predetermined time as unused link, and decreasing a control packet amount per unit time to the logical link that is determined as the unused link.
According to the second solving means of this invention, there is provided a passive optical network system comprising a station side apparatus and a plurality of home side apparatuses, in which the station side apparatus allocates uplink bandwidth to each of home side apparatuses by transmitting and receiving a control packets via logical links between the station side apparatus and each of home side apparatuses and provides allocated uplink bandwidth to the home side apparatuses, wherein
at least one of the home side apparatuses comprises:
a transfer database for storing transfer information for specifying a destination of frame transfer from the home side apparatus to a user terminal for each logical link;
a transfer processing part for performing a transfer process of a frame; and
a statistical counter for counting a transfer data amount for each logical link, and
the station side apparatus comprises:
a monitor control processing part for acquiring the transfer information of the transfer database and a count value of the statistical counter in the home side apparatus; and
a usage state management part for determining a logical link for which the transfer information is not registered in the transfer database and/or a logical link for which the count value of the statistical counter is not increased within a predetermined time as unused link, and decreasing a control packet amount per unit time to the logical link that is determined as the unused link.
According to the third solving means of this invention, there is provided a station side apparatus in a passive optical network system which includes the station side apparatus and a plurality of home side apparatuses, in which the station side apparatus allocates uplink bandwidth to each of home side apparatuses by transmitting and receiving a control packets via logical links between the station side apparatus and each of home side apparatuses and provides allocated uplink bandwidth to the home side apparatuses, the station side apparatus comprising:
a transfer database for storing transfer information for specifying a destination of frame transfer from the station side apparatus to the plurality of home side apparatuses for each logical link;
a transfer processing part for performing a transfer process of a frame;
a statistical counter for counting a transfer data amount for each logical link; and
a usage state management part for determining a logical link for which the transfer information is not registered in the transfer database and/or a logical link for which a count value of the statistical counter is not increased within a predetermined time as unused link, and decreasing a control packet amount per unit time to the logical link that is determined as the unused link.
According to the fourth solving means of this invention, there is provided a power consumption control method for use in a passive optical network system which includes a station side apparatus and a plurality of home side apparatuses, in which the station side apparatus allocates uplink bandwidth to each of home side apparatuses by transmitting and receiving a control packets via logical links between the station side apparatus and each of home side apparatuses and provides allocated uplink bandwidth to the home side apparatuses,
the method comprising steps of:
registering or deleting transfer information for specifying a destination of frame transfer from the station side apparatus to the plurality of home side apparatuses for each logical link in or from a transfer database by a process of a predetermined protocol in accordance with a transfer mode of the logical link;
counting a transfer data amount for each logical link; and
determining a logical link for which the transfer information is not registered in the transfer database and/or a logical link for which a count value of the statistical counter is not increased within a predetermined time as unused link, and decreasing a control packet amount per unit time to the logical link that is determined as the unused link.
According to the invention, it is possible to provide a passive optical network system, a station side apparatus and a power consumption control method capable of reducing the operation frequency of electronic circuits and optical devices in both the OLT and the ONT in an unused state by a user and reducing the power consumption while maintaining the continuity of service. Also, according to the invention, it is possible to provide user usage state management means for determining the use situation of the user accommodated in the PON system in the station side apparatus, and suppress a transmitting and receiving process for unnecessary control frames at the time of making the user unused determination in the state where the logical link between OLT and ONU is maintained.
The embodiments of the present invention will be described below with reference to the drawings.
The PON system has an OLT 4 that is a station side apparatus installed in a station house of a carrier, for example, and plural ONUs 2 installed in subscriber's homes, for example, which are connected via an optical fiber and an optical splitter 3. The ONU 2 has a UNI interface, to which a terminal or communication apparatus such as a personal computer, a router or a terminal adaptor within the user home is connected. In
The OLT 4 has an optical module 41, a PON control part 42, a DHCP/PPP processing part 43, a logical link transfer control part 44, a network node interface 45, an uplink frame distribution part 46, a downlink frame distribution part 47, an uplink multiplexing part 48, and a user usage state management part 49, for example.
The optical module 41 is a functional block of making the optical/electrical conversion, in which the optical signals of the PON are multiplexed or de-multiplexed with the uplink or downlink wavelength by a WDM 41b. In the case of a GE-PON of IEEE802.3ah, the uplink wavelength of 1.31 μm and the downlink wavelength of 1.49 μm are used. The uplink signal is converted from optical to electrical form by an O/E conversion part 41c, and the downlink signal is converted from optical to electrical form by an O/E conversion part 41a.
The PON control part 42 is a functional block for making the control with the ONUs 2 on the PON interface. A Discovery processing part 42a deals with a registration sequence in adding the new ONU 2 onto the PON. A DBA processing part 42b performs a polling control for transferring the uplink signal from the ONU 2 to the OLT 4 and an uplink bandwidth control on each logical link. In these Discovery process and DBA process, a protocol called a Multi Point Control Protocol (MPCP) is used. An Operation, Administration, and Maintenance (OAM) processing part 42c is a part for monitoring and controlling the ONUs 2, to make various kinds of settings on the ONU device, read the state, or make the fault notification using the OAM frame.
The logical link transfer control part 44 controls the frame transfer in the down direction of each logical link. The transfer database 44a has a transfer table for each logical link, in which the downlink frame is collated with this transfer table to decide the logical link for transfer. A statistical counter 44b adds up the number of uplink/downlink frames or the number of bytes transferred on each logical link.
The DHCP/PPP processing part 43 is a functional block for using the address of the layer 3 or equivalent in the transfer on the logical link. In the DHCP, the IP address is delivered to the terminal through a sequence like Discover-Offer-Request-Ack between the user terminal and the DHCP server, as defined in an Internet Engineering Task Force (IETF) RFC 2131. The DHCP/PPP processing part 43 snoops into this sequence, confirms the address extraction result, and registers the result of binding the L2 address (MAC) and the L3 address (IP) in the transfer database 44a. In this case, the downlink frame transfer is determined by a combination of the MAC address and the IP address. Likewise, it snoops into a disconnection sequence, and clears the concerned entry from the transfer database 44a if the address is released (freed). Also, it manages the address lease time extracted from the DHCP server, and clears the entry if the timer expires (Expires). For the DHCPv6 as defined in the RFC3315, the binding entry of the L2 address (MAC) and the L3 address (IPv6) is added to/deleted from the transfer database 44a based on the snoop result. For the PPPoE as defined in the RFC2516, the binding entry is similarly added or deleted, using the PPPoE session ID instead of the L3 address. The operation of the user usage state management part 49 will be described later in detail.
Next, a basic stream of data in the OLT 4 will be described below. An uplink frame received from the ONU 2 is converted into an electrical signal in the O/E conversion part 41c of the optical module 41, and inputted into the uplink frame distribution part 46. In the uplink frame distribution part 46, the frame format is analyzed, and the MPCP/OAM frame is distributed to the PON control part 42 and terminated. The DHCP/PPP frame is inputted into the DHCP/PPP processing part 43 for the snoop processing, multiplexed again with the user frame in the uplink multiplexing part 48, and inputted into the network node interface 45. The user frame is inputted into the logical link transfer control part 44. In the case where the mode of the logical link is the L2 mode, the source MAC address of the frame is registered in the transfer database 44a, and inputted into the network node interface 45. In the network node interface 45, the physical interface conversion is performed according to the NNI interface class.
The downlink data inputted from the NNI is inputted via the network node interface 45 into the downlink frame distribution part 47, where the frame format is analyzed. The user frame is inputted into the logical link transfer control part 44, and collated with the transfer database 44a to decide the logical link of transfer target. The concerned LLID is given to the frame, and outputted to the downlink multiplexing part 48. The DHCP/PPPoE frame is inputted into the DHCP/PPP processing part 43 for the snoop processing, and outputted to the downlink multiplexing part 48. These frames and the MPCP/OAM frame generated in the PON control part 42 are finally multiplexed in the downlink multiplexing part 48, converted into optical form in the optical module 41 and outputted to the PON section.
The ONU 2 has an optical module 23 for making the O/E conversion of the PON interface, an ONU control part 22 for making the frame transfer control of the ONU, and a network interface 21 for connection of the user terminal. The ONU control part 22 has a transfer database 22a and a statistical counter 22b for every network interface.
Next, the operation will be described below by comparing the switching between the normal mode and the power saving mode of this embodiment using a control sequence between OLT and ONU.
An ONU registration process 51 is called a Discovery, to which DISCOVERY_GATE is periodically sent from the OLT 4. If the ONU 2 is connected to the PON, it responds to this DISCOVERRY-GATE and sends REGISTER_REQ. The OLT 4 computes the distance to the ONU based on the response result from the ONU 2, and gives notice of the LLID with REGISTER. Thereafter, the OLT sends GATE describing the reply timing information from the ONU, and the ONU sends REGISTER ACK at the timing described in the GATE, completing the registration.
For a downlink data transfer 52 after registration, data is optically broadcast from the OLT 4 to the ONU 2, and the ONU 2 captures the data and outputs it to the terminal if the data is addressed to its own.
In an uplink data transfer (DBA) 53, POLL_GATE is periodically sent from the OLT 4 to the ONU 2. In an example of
The operation of this embodiment is shown in
The DBA processing part 42b of the OLT 4 performs a POLL_GATE sending process at the normal sending cycle (e.g., 1 ms). The user usage state management part 49 makes a used/unused determination 61 for determining whether the LLID is used or not. If the LLID is determined to be unused, the user usage state management part 49 instructs the DBA processing part 42b to make a mode change 62. The used/unused determination will be described later in detail. The DBA processing part 42b changes a process for this LLID to a power saving mode 63 to expand the sending cycle of POLL_GATE. In an example of
Next, the configuration of the transfer database 44a referred by the user usage state management part 49 and the used/unused determination with the transfer database 44a will be described below using
In this example, there are 128 LLIDs 71 from 3001 to 3128. For the state information 72, the “Registered” means that it is already registered and the “Deregistered” means that it is unconnected. For example, “Registered” is stored if the ONU is connected and the Discovery process of
In the L2 mode, the MAC learning is performed by registering the source MAC address 76 of the uplink frame in this database, and if there is no communication for a certain time, the MAC address 76 is erased from the database through an aging process. Also, the number of entry 75 is incremented by registering the address. The number of entry 75 is decremented by deleting the address. The update of the number of entry 75 is made in the same way in other modes. In
In the DHCP mode, the MAC address 76 and the allocated L3 address information (IP/Prefix 77) are registered as the entry in the database, based on the snoop result in the DHCP or DHCPv6 connection sequence. These addresses are erased based on the snoop result of the disconnection sequence and a DHCP lease timer. In
In the PPP mode, the MAC address 76 and the session ID 78 are registered as the entry in the database or erased from the database, based on the snoop result of the PPPoE sequence. In
In the VID mode, transferability is judged based on only the VID value of the OLT input frame. In this case, the MAC address 76 is not learned. Since it is necessary to perform a transparency process for all the frames matched with the VID, the unused link determination 79 corresponding to the LLID in the VID mode always represents used. For example, the number of entry may be always set to 1. In
In this database, the number of entry 75 of the LLIDs 3002, 3003 and 3127 is 0, and the state of the unused link determination 79 represents unused. When the user usage state management part 49 makes a unused link determination based on information in the transfer database 44a, these three LLIDs are determined as unused.
Next, the configuration of the statistical counter 44b referred by the user usage state management part 49 and the used/unused determination with the statistical counter 44b will be described below using
The statistical counter includes the LLID 81, an uplink counter previous acquisition value 82, an uplink counter current acquisition value 83, an increase 84 from the previous acquisition value to the current acquisition value, and unused link determination information 85.
The statistical counter acquires the number of transfer octets on each LLID at a predetermined time interval (e.g., a constant interval), and holds two values of the current acquisition value and the previous acquisition value. The user usage state management part 49 compares the current acquisition value and the previous acquisition value, and if the increase therebetween is zero (or smaller than a predetermined increase amount), determines to be unused. In
After registration, the ONU 2 is placed in a used state S42. Thereafter, if there is no increase of the counter, or each entry is cleared, it transits to a determination protection state S41. In an example of this determination protection, a protection time of 300 seconds is provided, and if there is no change in the counter or the entry state within this time period in this state, the state is determined as the user unused S43. The other appropriate protection time may be set beforehand. If the counter is increased or the entry is added to the transfer database during the determination protection time, it transits to used state. The transition from the unused state to the used state occurs if Queue>0 (uplink data is present) with REPORT of the ONU. Any one or both of the used/unused determination with the transfer database and the used/unused determination with the statistical counter may be employed.
Referring to
A PON control part 42 on the OLT 4 acquires the information of the ONU 2 from the ONU 2 with a function of the OAM processing part 42c, using an OAM frame. The user usage state management part 49 acquires the information of the transfer database 22a and the statistical counter 22b on the ONU 2 via the OAM processing part 42c, instead of determining the user usage state based on the information of the transfer database 44a and the statistical counter 44b for the OLT 4, and determines the usagestate of the ONU 2 based on the acquired information. The transfer database 22a, 22b of the ONU 2 stores at least the entry of LLID used by the own ONU among the entries as shown in
Also, a statistical counter determination flow of the user usage state management part 49 is shown in
Referring to
A PON system according to this embodiment has a station side apparatus and plural home side apparatuses, for example, which are connected via an optical fiber network having an optical splitter, in which the station side apparatus includes a DBA processing part for controlling the frame transfer in the direction from ONU to OLT, a transfer database part for managing the destination of user frame transfer from the OLT to plural ONUs, a statistical counter part for counting the transfer data amount of each user, and a user usage state management part for managing the user usage situation.
The user usage state management part determines the user usage situation based on the state monitoring result of one or all of the DBA processing part, the transfer database part and the statistical counter part, switches the operation of the DBA control part depending on the use situation and adjusts the control frame amount between OLT and ONU.
In this embodiment, the user is determined to be in the quite state based on the presence or absence of user traffic to reduce the DBA control frame amount for use in the user frame transfer between ONU and OLT when not in use, whereby it is possible to reduce the operation frequency of the electronic circuits and the optical devices for both of the OLT and ONU and reduce the power consumption even in a state where the user can employ the network, such as when various kinds of terminal is being connected to the ONU and the power of the terminal is on.
The invention is applicable to the PON system, for example.
Number | Date | Country | Kind |
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2010-259454 | Nov 2010 | JP | national |