JP4755879B2 - PPPoE client apparatus and PPPoE session disconnection method - Google Patents

Description

  The present invention relates to a PPPoE client apparatus capable of performing PPPoE communication and a PPPoE session disconnection method thereof.

  PPPoE (Point-to-Point Protocol over Ethernet (registered trademark)) is a method that realizes PPP (Point-to-Point Protocol) connection widely used as a data link layer protocol on Ethernet (registered trademark). Yes, specified in RFC2516 (see Non-Patent Document 1). PPPoE is widely used as a method for connecting user terminals and business facilities in broadband Internet connection services using ADSL (Asymmetric Digital Subscriber Line) and FTTH (Fiber To The Home).

  The following two points can be cited as backgrounds in which PPPoE is widely used. First, by using a PPP authentication method, connection authentication to a provider or service can be performed. Second, the client (user) uses a device ID such as the LAC (L2TP Access Concentrator) or LNS (L2TP Network Server) installed at the operator to perform authentication using the ID including the provider identifier. The provider can be dynamically switched and connected.

  An example of a connection form of a user, a provider (hereinafter referred to as an access provider for distinguishing from a provider), and a provider will be described with reference to FIG. FIG. 5A is a diagram showing a connection form of PPPoE, and FIGS. 5B, 5C, and 5D are protocol stack diagrams in the PPPoE client device, the LAC device, and the LNS device, respectively.

  In FIG. 5A, a PPPoE client device 1 in a user's home is bridge-connected to an LAC device 3 installed in an access provider's building via an access line 2 such as ADSL or FTTH. Here, the PPPoE client device 1 is a device that terminates PPPoE such as application software on a PC or a broadband router.

  As shown in FIG. 5B, in the PPPoE client device 1, a PPP layer is inserted between the MAC (Ethernet (registered trademark)) layer and the IP layer, and between the PPPoE client device 1 and the LAC device 3, PPP communication is possible.

  The PPPoE session started from the PPPoE client device 1 is terminated in the LAC device 3, and the LAC device 3 performs PPP authentication. In the LAC device 3, the PPP packets are aggregated for each connection destination provider by the provider identifier.

  As shown in FIG. 5C, in the LAC device 3, the L2TP layer is inserted under the PPP layer. L2TP is a data link layer protocol for tunneling PPP communications. Further, as shown in FIG. 5 (d), there is an L2TP layer below the PPP layer of the LNS device 5, and the LAC device 3 is installed at an interconnection point between the access provider and the providers 6A and 6B. The LNS device 5 is connected by tunneling using L2TP (Layer 2 Tunneling Protocol).

  Finally, in the LNS device 5, the connection destination providers are sorted according to the provider identifier, the PPP encapsulation is released, and the IP packet is transferred to the providers 6A and 6B.

  Next, a PPPoE session connection procedure between the PPPoE client device 1 and the LAC device 3 will be described. FIG. 6 is a sequence diagram showing a PPPoE session connection procedure.

  In starting a PPPoE session, first, in step S10, the PPPoE client apparatus 1 transmits a PADI (PPPoE Active Discovery Initiation) packet as a broadcast packet to the network side in order to search for the LAC apparatus 3.

  Next, in step S20, the LAC device 3 that has received the PADI packet returns a PADO (PPPoE Active Discovery Offer) packet to the PPPoE client device 1 as a response packet to the PADI packet.

  Subsequently, in step S30, the PPPoE client apparatus 1 transmits a PADR (PPPoE Active Discovery Request) packet by unicast to the LAC apparatus 3 that has returned the PADO packet, and requests to issue a session ID.

  Next, in step S40, the LAC device 3 transmits a PADS (PPPoE Active Discovery Session Confirmation) packet including the session ID. When the PPPoE client apparatus 1 receives this PADS packet, a PPPoE session is established.

  Thereafter, in step S50, the PPPoE client device 1 and the LAC device 3 perform communication by PPP. Thereafter, the same PPPoE session is managed by the session ID.

  When ending the PPPoE session, in step S60, a PPPoE Active Discovery Session Terminate (PADT) packet requesting PPPoE session termination is transmitted from either the PPPoE client device 1 or the LAC device 3, and the PPPoE session is terminated. To do.

  By the way, if an access provider allows a user to connect an unlimited number of PPPoE sessions, it will affect the equipment cost of the LAC device. Therefore, normally, the upper limit value of the number of PPPoE sessions that can be used simultaneously for one access line contract. Is set.

At the same time, in order to release an invalid PPPoE session, the LAC device 3 transmits an LCP Echo request packet for confirming connectivity to the PPPoE client device 1 at a constant time (T) interval, and continues PPPoE n times in succession. When there is no LCP Echo Reply from the client device 1, that is, after elapse of n × T time, the LAC device 3 generally transmits a PADT packet to the PPPoE client device 1 to end the PPPoE session. Yes.
IETF RFC2516 “A Method for Transmitting PPP Over Ethernet (registered trademark) (PPPoE)”, February 1999

  However, when a PPPoE client device such as a broadband router is making a PPPoE connection, an event such as a power failure occurs, and the PPPoE client device is turned off without successfully terminating the PPPoE session. Such a problem occurs.

  Generally, since a PPPoE client device does not hold a session ID in a nonvolatile memory or the like, it is necessary to newly start a PPPoE session after the power is turned on. Here, when the PPPoE connection is established with the maximum number of sessions permitted by the access provider before the power is turned off, the previous PPPoE session is held in the access provider's LAC device, as described above. The PPPoE session is not released until a certain time (n × T time) has elapsed. For this reason, there is a problem that it takes a long time to start a new PPPoE session.

  The present invention has been made in view of the above, and when the PPPoE client apparatus is turned off without normally terminating the PPPoE session in the state in which the PPPoE connection is established with the maximum number of sessions permitted by the access provider. Another object of the present invention is to provide a PPPoE client device and a PPPoE session disconnection method that reduce the time required to start a new PPPoE session after power is turned on.

  In order to achieve the above object, the invention according to claim 1 is a PPPoE client device that establishes a PPPoE session with a LAC device that distributes concentrated access for each connection destination. Data acquisition means for acquiring the MAC address of the LAC device and the session ID of the PPPoE session used before the power supply of the own device from the connectivity confirmation packet transmitted from the device to the own device; A packet for generating a termination request packet including the MAC address of the LAC device acquired in step 1 as a destination MAC address, the MAC address of the local device as a source MAC address, and the session ID acquired by the data acquisition unit as the local session ID Generated by the generating means and the packet generating means A packet of serial end request, characterized in that it comprises transmitting means for transmitting to the LAC device.

  The invention according to claim 2 is a PPPoE session disconnection method of a PPPoE client apparatus that establishes a PPPoE session with a LAC apparatus that distributes concentrated access for each connection destination, and after the PPPoE client apparatus is powered on, the LAC A data acquisition step of acquiring a MAC address of the LAC device and a session ID of a PPPoE session used before powering off the PPPoE client device from a connectivity confirmation packet transmitted from the device to the PPPoE client device; The MAC address of the LAC device acquired in this data acquisition step is the destination MAC address, the MAC address of the PPPoE client device is the source MAC address, and the set acquired in the data acquisition step is used. A packet generation step of generating a termination request packet including the session ID as its own session ID, and a transmission step of transmitting the termination request packet generated in the packet generation step to the LAC device. .

  According to the present invention, after the PPPoE client device is powered on, the MAC address of the LAC device and the PPPoE used before the PPPoE client device is turned off from the connectivity confirmation packet transmitted from the LAC device to the PPPoE client device. The session ID of the session is acquired, the MAC address of the LAC device is set as the destination MAC address, the MAC address of the PPPoE client device is set as the source MAC address, and the session ID acquired from the connectivity check packet is included as the own session ID. Since the request packet is generated and the termination request packet is transmitted to the LAC device, the power supply can be turned on without normally terminating the PPPoE session in the state where the PPPoE connection is established with the maximum number of sessions permitted by the access carrier. Cut off If it is, it is possible to shorten the time to start a new PPPoE session after power-up.

  The best mode for carrying out the PPPoE client apparatus and PPPoE session disconnection method of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a PPPoE client apparatus according to an embodiment of the present invention.

  As shown in FIG. 1, the PPPoE client device 1 according to the present embodiment includes a control unit 11 and a WAN port 12. The WAN port 12 is connected to the LAC device 3 via the access line 2 and outputs a packet transmitted from the LAC device 3 to the control unit 11.

  The control unit 11 includes a packet monitoring unit 111 that monitors a packet transmitted from the LAC device 3, a packet identifying unit 112 that identifies the packet, and an LAC from an LCP Echo Request packet that has the MAC address of the PPPoE client device 1 as a destination address. The data acquisition unit 113 that acquires the MAC address of the device 3 and the session ID of the PPPoE session, the packet generation unit 114 that generates a packet to be transmitted to the LAC device 3, the packet generated by the packet generation unit 114, and the LAC And a transmission / reception unit 115 that receives a packet transmitted from the device 3.

  Next, the operation of the PPPoE client apparatus of this embodiment and the PPPoE session disconnection method will be described.

  The PPPoE session disconnection method according to the present embodiment uses the PPPoE session used before the power is turned off when the PPPoE client device 1 is turned off without the PPPoE client device 1 normally ending the PPPoE session. In this method, the PPPoE client device 1 immediately opens after the power is turned on.

  FIG. 2 is a sequence diagram showing a procedure for disconnecting the PPPoE session between the PPPoE client apparatus and the LAC apparatus shown in FIG.

  First, when the power supply of the PPPoE client apparatus 1 is activated in step S110, in step S120, the packet monitoring unit 111 monitors packets received from the LAC apparatus 3 via the access line 2 after power activation. Then, the packet identification unit 112 determines whether there is an LCP Echo Request packet having the destination address as the MAC address of the PPPoE client apparatus 1 in the incoming packet.

  FIG. 3 is a diagram showing an LCP Echo Request packet. As shown in FIG. 3, the LCP Echo Request packet includes an Ethernet (registered trademark) header, a PPPoE header, a PPPoE payload, and a frame check sequence. The Ethernet (registered trademark) header includes a destination MAC address, a source MAC address, and an ether type. The PPPoE header includes information on version, type, code, session ID of PPPoE session, and data length of PPPoE payload. The PPPoE payload is composed of PPP protocol and LCP Echo Request data.

  Then, when the LCP Echo Request packet is transmitted from the LAC device 3 in step S130 and the packet identifying unit 112 determines that the packet is the LCP Echo Request packet having the MAC address of the PPPoE client device 1 as the destination MAC address, in step S140, the data The acquisition unit 113 reads the MAC address of the LAC device 3 from the transmission source MAC address of the Ethernet (registered trademark) header of the LCP Echo Request packet. Further, the data acquisition unit 113 reads the session ID of the PPPoE session that was used before power-off from the session ID of the PPPoE header. When a plurality of sessions are used, there are a plurality of session IDs.

  Next, in step S150, the packet generation unit 114 generates a PADT packet using the MAC address and session ID of the LAC device 3 acquired by the data acquisition unit 113.

  FIG. 4 is a diagram showing a PADT packet. As shown in FIG. 4, the PADT packet includes an Ethernet (registered trademark) header, a PPPoE header, a PPPoE payload, and a frame check sequence. The Ethernet (registered trademark) header includes a destination MAC address, a source MAC address, and an ether type. The PPPoE header includes information on version, type, code, session ID of PPPoE session, and data length of PPPoE payload.

  In step S150, the MAC address of the LAC device 3 is described as the destination MAC address, the MAC address of the PPPoE client device 1 is described as the source MAC address, and the session ID of the PPPoE session used before the power is turned off as the session ID Is generated.

  In step S160, the transmission / reception unit 115 transmits the PADT packet generated by the packet generation unit 114 to the LAC device 3.

  Thereafter, in step S <b> 170, the packet monitoring unit 111 monitors packets that arrive from the LAC device 3. Then, the packet identification unit 112 determines whether there is a PADT packet having the same session ID as the PADT packet generated by the packet generation unit 114 among the incoming packets.

  In step S180, when the PADT packet is transmitted from the LAC device 3, and the packet identification unit 112 determines that the PADT packet is a PADT packet having the same session ID as the PADT packet generated by the packet generation unit 114, PPPoE It is confirmed that the session has been released.

  Thereafter, the PPPoE session can be started according to the procedure shown in FIG.

  As described above, according to the PPPoE client apparatus and the PPPoE session disconnection method of the present embodiment, after the power supply of the PPPoE client apparatus 1 is started, the LAC apparatus 3 starts from the LCP Echo Request packet transmitted from the LAC apparatus 3 to the PPPoE client apparatus 1. The MAC address and the session ID of the PPPoE session used before powering off the PPPoE client device 1 are acquired, the MAC address of the LAC device 3 is set as the destination MAC address, and the MAC address of the PPPoE client device 1 is set as the source MAC. Since a PADT packet including the session ID acquired from the LCP Echo Request packet as its own session ID is generated and transmitted to the LAC device 3, the LAC device 3 possesses it when the power is turned on. Since it is possible to receive an LCP Echo Request packet within at least T time and there is no need to wait until the LAC device 3 releases the session as in the prior art, The time for starting a new PPPoE session can be significantly reduced.

  It should be noted that the present invention is also effective when an operation error occurs in the PPPoE client device during PPPoE connection and it is necessary to reboot the PPPoE client device.

It is a block diagram which shows the PPPoE client apparatus of embodiment of this invention. It is a sequence diagram which shows the procedure which disconnects the PPPoE session between the PPPoE client apparatus and LAC apparatus shown in FIG. It is a figure which shows a LCP Echo Request packet. It is a figure which shows a PADT packet. (A) is a diagram showing a connection form of PPPoE, (b) is a protocol stack diagram in the PPPoE client device, (c) is a protocol stack diagram in the LAC device, and (d) is a protocol stack diagram in the LNS device. It is a sequence diagram which shows a PPPoE session connection procedure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 PPPoE client apparatus 2 Access line 3 LAC apparatus 5 LNS apparatus 6A, 6B Provider 11 Control part 12 WAN port 111 Packet monitoring part 112 Packet identification part 113 Data acquisition part 114 Packet generation part 115 Transmission / reception part

Claims (2)

In a PPPoE client device that establishes a PPPoE session with a LAC device that distributes concentrated access for each connection destination,
Obtain the MAC address of the LAC device and the session ID of the PPPoE session that was used before turning off the power of the device from the connectivity confirmation packet sent from the LAC device to the device after the power of the device is turned on. Data acquisition means;
End request packet including the MAC address of the LAC device acquired by the data acquisition unit as a destination MAC address, the MAC address of the local device as a source MAC address, and the session ID acquired by the data acquisition unit as the local session ID Packet generating means for generating
A PPPoE client device comprising: a transmission unit configured to transmit the termination request packet generated by the packet generation unit to the LAC device. In a PPPoE session disconnection method of a PPPoE client device that establishes a PPPoE session with a LAC device that distributes concentrated access for each connection destination,
After powering on the PPPoE client device, the MAC address of the LAC device from the connectivity confirmation packet sent from the LAC device to the PPPoE client device and the PPPoE session used before powering off the PPPoE client device A data acquisition step of acquiring the session ID of
Termination request including the MAC address of the LAC device acquired in this data acquisition step as a destination MAC address, the MAC address of the PPPoE client device as a source MAC address, and the session ID acquired in the data acquisition step as its own session ID A packet generation step for generating a packet of
A PPPoE session disconnection method, comprising: a transmission step of transmitting the termination request packet generated in the packet generation step to the LAC device.

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