JP2014155097A - Ge-pon system and olt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an IPv4 address dispensing count limiting function without imposing limitations on a physical address learning count.SOLUTION: An OLT 8 comprises: a frame transfer unit 821 for transferring a frame between an ONU 6 and a host network 1 connected to a higher level; a DHCP dispensing count confirmation unit 822 for confirming the number of IPv4 addresses dispensed by a DHCP when a DHCP Discover frame which is an IPv4 frame is received via the ONU 6 from a subscriber terminal 3; a frame destruction unit 823 for destructing the IPv4 frame concerned when the IPv4 address dispensing count is determined to have no vacancy; and a DHCP dispensing control unit 824 for instructing, when the IPv4 address dispensing count is determined to have a vacancy, the frame transfer unit 821 so as to transfer the IPv4 frame concerned to the host network 1, so that an IPv4 address is dispensed by the DHCP to the subscriber terminal 3 which is the transmission source of the IPv4 frame.

Description

  In the present invention, a station side device (OLT: Optical Line Terminal) and a subscriber side device (ONU: Optical Network Unit) are connected via an optical fiber (optical transmission medium), and Ethernet (registered trademark / hereinafter, described below) In the GE-PON (Gigabit Ethernet (registered trademark) -Passive Optical Network) system in which the ONU and the subscriber home terminal are connected, the service provider assigns the number of IPv4 addresses assigned to the subscriber home terminal. The present invention relates to a GE-PON system and OLT to be controlled.

  A GE-PON system is known as a conventional network system (see, for example, Non-Patent Document 1). In the GE-PON system, the ONU is connected to the OLT by an optical fiber via an optical splitter. In this GE-PON system, since a plurality of ONUs share one OLT and no special device is required for branching / coupling of optical fibers, it is possible to construct an economical network.

  On the other hand, in recent years, IPv6 has been formulated as a countermeasure for the IPv4 global address exhaustion problem. However, it still takes time to fully transition from IPv4 to IPv6. Currently, each service provider handles this by assigning a private address to each subscriber. For this reason, each service provider carries out maintenance and operation of a DHCP (Dynamic Host Configuration Protocol) server, but the load on the DHCP server increases as the number of subscribers increases. Therefore, there is a need for a function that limits the IP addresses assigned to subscribers.

  Therefore, in the conventional technology, a limit is imposed on the number of learning of physical addresses (MAC address: Media Access Control address) in the ONU for a network configuration in which an HGW (Home Gate Way) or PC that supports only IPv4 is connected to the ONU. This limits the number of IP address payouts. When more than the maximum number of subscribers connected to the ONU is connected to the ONU, only the IP frame having the physical address learned (stored) at the UNI port of the ONU as the transmission source is transmitted, and the physical address that has not been learned All the IP frames having the transmission source are discarded by the ONU.

IEEE (The Institute of Electrical and Electronic Engineers) 802.3ah

On the other hand, in recent years when the introduction of IPv6 has begun in earnest, there is a possibility that the physical address of IPv6 is different from the physical address of IPv4 in a subscriber home terminal equipped with an IPv6 pass-through function. For this reason, when the limit on the number of learning physical addresses is exceeded in the conventional technology, communication using IPv6 is blocked by the ONU.
Therefore, when a subscriber home terminal corresponding to the IPv6 pass-through function is connected, it is necessary to set the learning limit number in consideration of the number of terminals. However, such setting also leads to illegally permitting the delivery of IPv4 addresses, and therefore cannot satisfy the service provider's request to limit the number of IPv4 addresses to be paid out. Therefore, in the method of limiting the learning number of physical addresses as in the prior art, it is difficult to set the learning limit number of physical addresses when a subscriber home terminal that supports the IPv6 pass-through function is connected. There was a problem.

  The present invention has been made to solve the above-described problems. A GE-PON system and an OLT capable of obtaining a payout number limiting function for IPv4 addresses without limiting the number of learning physical addresses. It is intended to provide.

  The GE-PON system according to the present invention includes an OLT connected via an optical transmission medium to an ONU to which a subscriber premises terminal is connected at a lower level, and the OLT includes an upper network connected to the ONU and an upper level. A frame transfer unit that transfers frames between them, and when a DHCP Discover frame that is an IPv4 frame is received from a subscriber home terminal via the ONU by the frame transfer unit, the number of IPv4 addresses issued by DHCP is confirmed. The DHCP payout number confirmation unit to be performed, and the DHCP payout number confirmation unit to determine that there is no free IPv4 address payout number, the frame discard unit for discarding the target IPv4 frame, and the DHCP payout number check unit from the IPv4 address If it is determined that there is a vacant number of payouts, the target IPv4 frame It instructs the frame transfer unit to transfer to the upper network, in which a DHCP payout control unit for payout of IPv4 addresses by DHCP to the subscriber premises terminal serving as a transmission source of the IPv4 frame.

  According to the present invention, since it is configured as described above, an IPv4 address payout number limiting function can be obtained without limiting the learning number of physical addresses.

It is a figure which shows the general network structure containing the GE-PON system by Embodiment 1 of this invention. It is a figure which shows the whole structure of the GE-PON system by Embodiment 1 of this invention. It is a figure which shows the structure of ONU by Embodiment 1 of this invention. It is a figure which shows the structure of the PON interface card of OLT by Embodiment 1 of this invention. It is a figure which shows the structure of the subscriber home terminal by Embodiment 1 of this invention. It is a sequence diagram which shows the payout method of the IPv4 address in the conventional GE-PON system. It is a sequence diagram which shows the payout method of the IPv4 address in the GE-PON system by Embodiment 1 of this invention. It is a sequence diagram which shows the payout method of the IPv4 address in the GE-PON system by Embodiment 2 of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
Embodiment 1 FIG.
FIG. 1 is a diagram showing a general network configuration including a GE-PON system according to Embodiment 1 of the present invention.
As shown in FIG. 1, this network includes a host network 1, a plurality of GE-PON systems 2 (GE-PON systems 2a to 2b in FIG. 1), and a plurality of subscriber home terminals 3 (subscribers in FIG. 1). Home terminals 3a to 3e).

  The GE-PON system 2 is connected to the higher level network 1 by N: 1 via the Ethernet cable 4 (Ethernet cables 4a to 4f in FIG. 1). The subscriber home terminal 3 is connected to the corresponding GE-PON system 2 via the Ethernet cable 5 (Ethernet cables 5a to 5e in FIG. 1). Each subscriber home terminal 3 has a different configuration depending on the terminal 3.

Next, the configuration of the GE-PON system 2 will be shown.
FIG. 2 is a diagram showing the configuration of the GE-PON system 2a according to Embodiment 1 of the present invention. In FIG. 2, the description will be made using the GE-PON system 2 a, but the same applies to other GE-PON systems 2.
As shown in FIG. 2, the GE-PON system 2 a includes a plurality of ONUs 6 (ONUs 6 a to 6 c in FIG. 2), an optical splitter 7, and an OLT 8.

  The ONU 6 is connected to the subscriber's home terminal 3 via the Ethernet cable 5 and is connected to the optical splitter 7 via branch optical fibers 9 (branch optical fibers 9a to 9c in FIG. 2). The OLT 8 is connected to the optical splitter 7 via the trunk optical fiber 10 and is connected to the higher level network 1 via the Ethernet cable 4. The optical splitter 7 is a device that branches and couples optical fibers 9 and 10 that are optical transmission media for optical signals.

A monitoring control card 81 is inserted into the OLT 8. The supervisory control card 81 controls the operation parameters of the OLT 8 and manages the status of each device. This supervisory control card 81 holds system data 811 of the entire OLT 8.
A PON interface card 82 (PON interface cards 82a to 82c in FIG. 2) is inserted into the OLT 8. The ONU 6 is connected to one of the PON interface cards 82 (PON interface card 82a in FIG. 2) via the optical fibers 9 and 10 and the optical splitter 7. The PON interface card 82 controls communication according to the contents of the system data 811 held by the monitoring control card 81.

  Here, in the conventional GE-PON system, as described above, IP address payout is restricted by restricting the number of physical addresses learned in the ONU. When the limit on the number of learned physical addresses is exceeded, if it is determined that the physical address of the frame from the subscriber home terminal 3 is a physical address that has not been learned (stored) in the UNI port of the ONU, The frame was discarded. In contrast, in the ONU 6 of the GE-PON system 2 according to the first embodiment, the learning number of physical addresses is set to an unlimited or necessary and sufficient value.

  In the GE-PON system 2 according to the first embodiment, the number of IPv4 addresses issued by DHCP is limited in the PON interface card 82 of the OLT 8. When the number of IPv4 address payouts by DHCP is exceeded for each Ethernet cable 5 connected to the ONU 6, the IPv4 frame from the subscriber home terminal 3 to which no IPv4 address has been paid out is discarded.

Next, the configuration of the ONU 6 will be shown.
FIG. 3 is a diagram showing the configuration of the ONU 6a according to the first embodiment of the present invention. In FIG. 3, the description will be made using the ONU 6 a, but the same applies to other ONUs 6.
As shown in FIG. 3, the ONU 6 a includes a frame transfer unit 61, a physical address learning number check unit 62, and a physical address learning unit 63.

  When the frame transfer unit 61 receives a frame (IPv4 frame or IPv6 frame) from the subscriber home terminal 3 via the Ethernet cable 5, the frame transfer unit 61 transmits the frame via the optical fibers 9 and 10 and the optical splitter 7 to the OLT 8. To the PON interface card 82. When the frame transfer unit 61 receives a frame from the PON interface card 82 of the OLT 8 via the optical fibers 9 and 10 and the optical splitter 7, the frame transfer unit 61 transmits the frame via the Ethernet cable 5 to the corresponding subscriber home. Transfer to terminal 3.

The physical address learning number confirmation unit 62 confirms the learning number of the physical address when the frame transfer unit 61 receives a frame from the subscriber home terminal 3.
The physical address learning unit 63 learns the physical address of the target frame when the physical address learning number confirmation unit 62 determines that there is a free physical address learning number. The learning address learning limit number by the physical address learning unit 62 is set to an unlimited or necessary and sufficient value.

Next, the configuration of the PON interface card 82 of the OLT 8 is shown.
FIG. 4 is a diagram showing a configuration of the PON interface card 82a of the OLT 8 according to the first embodiment of the present invention. In FIG. 4, the description will be made using the PON interface card 82a, but the same applies to the other PON interface cards 82.
As shown in FIG. 4, the PON interface card 82 a of the OLT 8 includes a frame transfer unit 821, a DHCP payout number confirmation unit 822, a frame discard unit 823, and a DHCP payout control unit 824.

  When the frame transfer unit 821 receives a frame (IPv4 frame or IPv6 frame) from the ONU 6 via the optical fibers 9 and 10 and the optical splitter 7, the frame transfer unit 821 transfers the frame to the upper network 1 via the Ethernet cable 4. To do. Further, when the frame transfer unit 821 receives a frame from the upper network 1 via the Ethernet cable 4, the frame transfer unit 821 transfers the frame to the corresponding ONU 6 via the optical fibers 9 and 10 and the optical splitter 7.

  The DHCP payout number confirmation unit 822 confirms the number of IPv4 addresses to be paid out by DHCP when the frame transfer unit 821 receives a DHCP Discover frame that is an IPv4 frame from the subscriber home terminal 3 via the ONU 6. is there.

  The frame discard unit 823 discards the target IPv4 frame when the DHCP payout number confirmation unit 822 determines that there is no free IPv4 address payout number by DHCP.

  The DHCP payout control unit 824 instructs the frame transfer unit 821 to transfer the target IPv4 frame to the upper network 1 when the DHCP payout number confirmation unit 822 determines that the IPv4 address payout number by DHCP is empty. Then, the IPv4 address is paid out by DHCP to the subscriber home terminal 3 which is the transmission source of the IPv4 frame.

Next, the configuration of the subscriber home terminal 3 will be described.
FIG. 5 is a diagram showing a configuration of the subscriber home terminal 3a according to the first embodiment of the present invention. In FIG. 5, the description will be given using the subscriber home terminal 3 a, but the same applies to other subscriber home terminals 3.
As shown in FIG. 5, the subscriber home terminal 3a includes a BB (BroadBand) router 11 and a PC 12 (PCs 12a to 12c in FIG. 5). The PC 12 is connected to the BB router 11 via a line 13 (lines 13a to 13c in FIG. 5).

The BB router 11 performs Internet communication using an IP address acquired from the upper network 1 or a predetermined IP address. Further, when transferring the frame received from the PC 12 to the ONU 6, the BB router 11 changes the physical address of the transmission source from the physical address of the PC 12 to the physical address of the BB router 11.
However, when the BB router 11 is compatible with the IPv6 pass-through function, the frame received from the PC 12 is transferred to the ONU 6 without changing the physical address of the PC 12. That is, since the ONU 6 sets the learning number of physical addresses to an unlimited or necessary and sufficient value, Internet communication can be performed even if the physical address is transferred to the ONU 6 without being changed.

  The PC 12 performs Internet communication using an IP address assigned from the BB router 11 or a predetermined IP address.

Next, a method for paying out an IPv4 address by the GE-PON system 2 configured as described above will be described in comparison with the prior art.
First, a method for paying out an IPv4 address in the prior art will be described with reference to FIG. In the following, an example will be described in which two subscriber home terminals 3a and 3f are connected to the ONU of the conventional GE-PON system, and the number of IPv4 addresses that can be paid out is one.

  As shown in FIG. 6, when a DHCP Discover frame, which is an IPv4 frame, is transmitted from the subscriber's home terminal 3a, first, the ONU receives this frame and checks the learning number of physical addresses (step ST601, ST601). 602). Since the learning number is empty at the time of initial construction, the received frame is transferred to the PON interface card of the OLT (step ST603).

Next, the PON interface card transfers the received frame to the upper network 1 as it is (step ST604).
Thereafter, in the IP address delivery sequence by DHCP, the processing from DHCP Offer to DHCP Ack is sequentially performed (steps ST605 to 613). Thereby, the delivery of the IPv4 address to the subscriber home terminal 3a is completed.

  On the other hand, when an IPv6 frame that is a physical address other than the BB router 11 is transmitted from the subscriber home terminal 3a, the ONU receives this frame and confirms the learning number of the physical address in the same manner as described above (step ST614). 615). In this case, since there is no available learning number, learning of the physical address becomes impossible and the IPv6 frame is discarded.

  When the DHCP Discover frame, which is an IPv4 frame, is transmitted from the subscriber home terminal 3f after the delivery of the IPv4 address to the subscriber home terminal 3a is completed, the ONU receives this frame, and the same as above. Then, the number of learning physical addresses is confirmed (steps ST616, 617). In this case, since there is no available learning number, learning of the physical address becomes impossible and the received frame is discarded.

  Next, an IPv4 address issue method in the GE-PON system 2 of the present invention will be described with reference to FIG. In the following, as in FIG. 6, the case where two subscriber home terminals 3a and 3f are connected to the ONU 6a of the GE-PON system 2a of the present invention and the number of IPv4 addresses that can be issued is one is taken as an example. explain.

  As shown in FIG. 7, when a DHCP Discover frame, which is an IPv4 frame, is transmitted from the subscriber's home terminal 3a, first, the frame transfer unit 61 of the ONU 6a receives this frame and directly sends it to the PON interface card 82a of the ONU 8. Transfer (steps ST701 and 702).

Next, the DHCP payout number confirmation unit 822 of the PON interface card 82a confirms the payout number of the IPv4 address by DHCP (step ST703). At the time of initial construction, since there is a vacant number of IPv4 address payouts by DHCP, the frame transfer unit 821 transfers the received frame to the upper network 1 in accordance with an instruction from the DHCP payout control unit 824 (step ST704). ).
Thereafter, the processing from DHCP Offer to DHCP Ack is sequentially performed in the IP address issue sequence by DHCP (steps ST705 to 713). Thereby, the delivery of the IPv4 address to the subscriber home terminal 3a is completed.

  On the other hand, when an IPv6 frame that is a physical address other than the BB router 11 is transmitted from the subscriber home terminal 3a, the frame transfer unit 61 of the ONU 6a receives this frame and transfers it directly to the PON interface card 82a of the OLT 8 ( Step ST714, 715). Next, the frame transfer unit 821 of the PON interface card 82a similarly receives this frame and transfers it directly to the upper network 1 (step ST716). Thereby, communication by IPv6 becomes possible.

  When the DHCP Discover frame, which is an IPv4 frame, is transmitted from the subscriber home terminal 3f after the delivery of the IPv4 address to the subscriber home terminal 3a is completed, the frame transfer unit 61 of the ONU 6a receives this frame. Then, the data is directly transferred to the PON interface card 82a of the OLT 8 (steps ST717 and 718). Next, the DHCP payout number confirmation unit 822 of the PON interface card 82a confirms the payout number of the IPv4 address by DHCP in the same manner as described above (step ST719). In this case, since there is no available IPv4 address delivery number by DHCP, the frame discard unit 823 discards the frame received by the frame transfer unit 821.

  As described above, according to the first embodiment, the GE-PON system 2 is provided with a function for limiting the number of IPv4 addresses to be paid out by DHCP and an IPv6 pass-through function, so that a subscriber corresponding to the IPv6 pass-through function is provided. Even when the home terminal 3 is connected under the ONU 6, it is possible to obtain an IPv4 address payout number limiting function and an IPv6 pass-through function without limiting the learning number of physical addresses.

Embodiment 2. FIG.
In the first embodiment, the IPv4 address payout method at the time of initial construction has been described. On the other hand, in the second embodiment, a method for paying out an IPv4 address when the physical address of the subscriber home terminal 3 is changed due to a change in the subscriber home environment (when the subscriber home terminal 3 is replaced). explain.
In addition, each structure in Embodiment 2 is the same as each structure shown in FIGS. 1-5, The description is abbreviate | omitted.

  As shown in FIG. 8, when the physical address of the subscriber home terminal 3a is changed after the delivery of the IPv4 address to the subscriber home terminal 3a is completed (step ST801), the subscriber home terminal 3a The DHCP Release frame is transmitted, and the frame transfer unit 61 of the ONU 6a receives this frame and transfers it directly to the PON interface card 82a of the OLT 8 (steps ST802 and 803).

  Next, the DHCP payout control unit 824 of the PON interface card 82a confirms the IPv4 address payout number by DHCP of the DHCP payout number check unit 822, and the source (subscriber home terminal) of the IPv4 frame received by the frame transfer unit 821 The IPv4 address assigned to 3a) is released (steps ST804 and 805). As a result, there is a vacancy in the number of IPv4 address payouts by DHCP.

  Thereafter, when a DHCP Discover frame that is an IPv4 frame is transmitted from the subscriber home terminal 3f, the frame transfer unit 61 of the ONU 6a receives this frame and transfers it directly to the PON interface card 82a of the OLT 8 (steps ST806 and 807). ). Next, the DHCP payout number confirmation unit 822 of the PON interface card 82a confirms the number of payouts of the IPv4 address by DHCP (step ST808). In this case, since there is a vacant number of IPv4 addresses to be paid out by DHCP, IPv4 addresses are paid out to the subscriber home terminal 3f (steps ST809 to 816).

  As described above, according to the second embodiment, when a physical address of a subscriber home terminal 3 is changed after an IPv4 address is paid out to a certain subscriber home terminal 3, it is paid out. Since the configuration is such that the IPv4 address is released, it becomes possible to reuse the IPv4 address that has become unnecessary.

  In the present invention, within the scope of the invention, any combination of the embodiments, or any modification of any component in each embodiment, or omission of any component in each embodiment is possible. .

  DESCRIPTION OF SYMBOLS 1 High-order network, 2, 2a-2b GE-PON system, 3, 3a-3f Subscriber home terminal, 4, 4a-4f, 5, 5a-5e Ethernet cable, 6, 6a-6c ONU, 7 Optical splitter, 8 OLT, 9, 9a to 9c Branch optical fiber (optical transmission medium), 10 trunk optical fiber (optical transmission medium), 11 BB router, 12, 12a to 12c PC, 13, 13a to 13c line, 81 supervisory control card, 811 System data, 82, 82a to 82c PON interface card, 61 frame transfer unit, 62 physical address learning number confirmation unit, 63 physical address learning unit, 821 frame transfer unit, 822 DHCP payout number confirmation unit, 823 frame discard unit, 824 DHCP Payout control unit.

Claims (6)

In a GE-POB system having an OLT connected via an optical transmission medium to an ONU to which a subscriber's home terminal is connected in the lower level,
The OLT is
A frame transfer unit for transferring a frame between the ONU and an upper network connected to the upper level;
A DHCP payout number confirmation unit for confirming the number of IPv4 addresses to be paid out by DHCP when the frame transfer unit receives a DHCP Discover frame that is an IPv4 frame from the subscriber home terminal via the ONU;
A frame discarding unit for discarding a target IPv4 frame when it is determined by the DHCP payout number confirmation unit that there is no free IPv4 address delivery number;
When the DHCP payout number confirming unit determines that there is a free IPv4 address payout number, the frame transfer unit is instructed to transfer the target IPv4 frame to the upper network, and the source of the IPv4 frame is transmitted. And a DHCP payout control unit for paying out an IPv4 address by DHCP to the subscriber home terminal. 2. The GE-PON system according to claim 1, wherein the frame forwarding unit forwards the IPv6 frame to the upper network when receiving an IPv6 frame from the subscriber home terminal via the ONU. 3. The DHCP payout control unit, when a DHCP Release frame that is an IPv4 frame is received from the subscriber home terminal via the ONU by the frame transfer unit, an IPv4 address assigned to the subscriber home terminal. The GE-PON system according to claim 1 or 2, wherein release is performed. In an OLT connected via an optical transmission medium to an ONU to which a subscriber home terminal is connected in the lower level,
An OLT-side frame transfer unit that transfers frames between the ONU and a higher-level network connected to the upper level;
A DHCP payout number confirmation unit for confirming the number of IPv4 addresses to be paid out by DHCP when the frame transfer unit receives a DHCP Discover frame that is an IPv4 frame from the subscriber home terminal via the ONU;
A frame discarding unit for discarding a target IPv4 frame when it is determined by the DHCP payout number confirmation unit that there is no free IPv4 address delivery number;
When the DHCP payout number confirming unit determines that there is a free IPv4 address payout number, the frame transfer unit is instructed to transfer the target IPv4 frame to the upper network, and the source of the IPv4 frame is transmitted. An OLT comprising: a DHCP payout control unit for paying out an IPv4 address by DHCP to the subscriber home terminal. The OLT according to claim 4, wherein the frame transfer unit transfers the IPv6 frame to the upper network when receiving an IPv6 frame from the subscriber premises terminal via the ONU. The DHCP payout control unit, when a DHCP Release frame that is an IPv4 frame is received from the subscriber home terminal via the ONU by the frame transfer unit, an IPv4 address assigned to the subscriber home terminal. 6. The OLT according to claim 4, wherein release is performed.

Images