WO2014090194A1

WO2014090194A1 - Dialing method of terminal device, and access device

Info

Publication number: WO2014090194A1
Application number: PCT/CN2013/089424
Authority: WO
Inventors: 赵胜涛; 薛俊杰; 张成国; 张少毅; 李春梅
Original assignee: 华为技术有限公司
Priority date: 2012-12-13
Filing date: 2013-12-13
Publication date: 2014-06-19
Also published as: CN103873335B; CN103873335A

Abstract

The present invention provides a dialing method of a terminal device, and an access device. The method comprises: an access device sending a detection message to a network, obtaining a media access control (MAC) address of an on-line broadband remote access server (BRAS), and saving the obtained MAC address of the BRAS in a BRAS list; sending a handshake message to a BRAS corresponding to a MAC address in the BRAS list, so as to obtain whether the corresponding BRAS is in an off-line state; obtaining a MAC address of a BRAS in an off-line state, and obtaining, from a correspondence relationship between a MAC address of a BRAS and a MAC address and a Session ID of a terminal device, a MAC address and a Session ID of a terminal device serving the BRAS in an off-line state; and sending an off line notification message to a corresponding terminal device according to the obtained MAC address and Session ID of the terminal device, so that the corresponding terminal device performs dialing.

Description

Terminal device dialing method and access device

This application claims priority to Chinese Patent Application No. 201210538919.7, entitled "Dialing Method and Access Device for Terminal Equipment", filed on December 13, 2012, the entire contents of which are incorporated herein by reference. In the application.

The present invention relates to communications technologies, and in particular, to a dialing method and an access device for a terminal device. Background technique

Currently, broadband operators often use multiple Broadband Remote Access Servers (BRAS) or multiple ports on a BRAS to share users and traffic. In addition, when the user dials the PPP (Point To Point Protocol Over Ethernet; PPPoE), the connection is established with the first responding BRAS, that is, the first responding BRAS is selected as the authentication server. After the terminal establishes a connection with the BRAS, the terminal establishes a Link Control Protocol (LCP) handshake with the BRAS every predetermined time to determine whether the BRAS is faulty. When the BRAS fails, the LCP handshake between the terminal and the BRAS will time out continuously, causing the terminal to dial down to other working BRASs.

However, by establishing an LCP handshake between the terminal and the BRAS, it is determined that the process of re-dialing to the BRAS of the normal working BRAS after the failure of the BRAS is several tens of seconds to several minutes, thus causing a long service interruption time. A problem that the user perceives poorly.

Summary of the invention

The present invention provides a dialing method and an access device for a terminal device, which are used to reduce service interruption time caused by offline failure due to BRAS failure or connection failure.

A first aspect of the present invention provides a method for dialing a terminal device, including:

The access device sends a probe packet to the network, obtains a media access control MAC address of the online broadband access server BRAS, and stores the obtained MAC address of the BRAS in the BRAS list; the access device is in the BRAS list. The BRAS corresponding to the MAC address sends a handshake message to obtain the current state of the corresponding BRAS;

The access device acquires the MAC address of the BRAS in an offline state, from the MAC of the BRAS Obtaining, in the correspondence between the address and the MAC address of the terminal device and the session session ID, the MAC address and the Session ID of the terminal device belonging to the BRAS in the offline state;

The access device sends an offline notification message to the corresponding terminal device according to the obtained MAC address and the session ID of the terminal device, so that the corresponding terminal device performs dialing.

In a first possible implementation manner of the first aspect, the access device sends a probe packet to the network, obtains a media access control MAC address of the online broadband access server BRAS, and saves the acquired MAC address of the BRAS. In the BRAS list, specifically:

The access device sends an Ethernet bearer point-to-point protocol PPPoE activation discovery start packet PADI message to the BRAS in the network;

The access device receives the PADO packet of the PPPoE activation discovery phase service packet of the BRAS, obtains the MAC address of the BRAS from the PADO message, and stores the acquired MAC address of the BRAS into the BRAS list.

With reference to the first aspect, in a second possible implementation manner of the first aspect, the access device sends a probe packet to the network, and obtains a media access control MAC address of the online broadband access server BRAS, which is obtained. The MAC address of the BRAS is saved in the BRAS list, including:

The access device sends an address resolution protocol ARP^ message to the BRAS corresponding to the IP address according to the pre-configured BRAS IP address;

The access device receives the ARP response packet of the BRAS, obtains the MAC address of the BRAS corresponding to the IP address from the ARP response packet, and stores the obtained MAC address in the BRAS list.

With reference to the first aspect, in a third possible implementation manner of the first aspect, the access device sends a probe packet to the network, and obtains a media access control MAC address of the online broadband access server BRAS, which is obtained by After the MAC address of the BRAS is saved in the BRAS list, the method further includes:

The access device monitors the dialing process of the terminal device to the BRAS, obtains the MAC address of the terminal device, the MAC address of the BRAS, and the session ID from the dialing process of the terminal device, and obtains the MAC address of the terminal device and the MAC address of the BRAS. The address and the session ID form a correspondence relationship and are saved to the access device.

With reference to the third possible implementation manner of the first aspect, in a fourth possible implementation manner of the first aspect, the access device monitors a dialing process of the terminal device to the BRAS, and the dialing process of the slave terminal device Obtain the MAC address of the terminal device, the MAC address of the BRAS, and the Session ID. Specifically include:

The access device receives the BRAS Ethernet bearer point-to-point protocol PPPoE activation discovery session acknowledgement packet PADS message;

The access device stores, in the PADS packet, a MAC address of the terminal device, a MAC address of the BRAS, and a session ID in a corresponding relationship on the access device.

A second aspect of the present invention provides an access device, including: a first transceiver, configured to send a probe packet to a network, obtain a media access control MAC address of an online broadband access server BRAS, and obtain a BRAS. The MAC address is saved in the BRAS list;

a second transceiver, configured to send a handshake message to the BRAS corresponding to the MAC address in the BRAS list, to obtain a current state of the corresponding BRAS;

a processor, configured to obtain a MAC address of the BRAS in an offline state, and obtain a MAC address of the terminal device belonging to the offline BRAS from the correspondence between the MAC address of the BRAS and the MAC address of the terminal device and the session session ID Session ID;

a third transceiver, configured to send a offline notification message to the corresponding terminal device according to the obtained MAC address and the session ID of the terminal device, so that the corresponding terminal device performs dialing;

a memory for storing the BRAS list.

In a first possible implementation manner of the second aspect, the first transceiver specifically includes: a data transmitter, configured to send an Ethernet bearer point-to-point protocol PPPoE activation discovery start packet PADI to a BRAS in the network ;

The data receiver is configured to receive the PADO packet of the PPPoE activation discovery phase service packet of the BRAS, obtain the MAC address of the BRAS from the PADO packet, and store the obtained MAC address of the BRAS into the BRAS list.

With reference to the second aspect, in a second possible implementation manner of the second aspect, the first transceiver specifically includes:

a data sender, configured to send an address resolution protocol ARP^ message to the BRAS corresponding to the IP address according to the pre-configured BRAS IP address;

The data receiver is configured to receive the ARP response packet of the BRAS, obtain the MAC address of the BRAS corresponding to the IP address from the ARP response packet, and store the obtained MAC address in the BRAS list.

In conjunction with the first possible implementation of the second aspect, a third possible implementation in the second aspect The second transceiver is further configured to forward the packet of the terminal device to the BRAS dialing process; the processor is further configured to obtain the MAC address of the terminal device and the MAC address of the BRAS from the dialing process of the terminal device. The address and the session ID are stored in the memory by the MAC address of the terminal device, the MAC address of the BRAS, and the session ID.

With reference to the second aspect, the third possible implementation manner of the third aspect, in the fourth possible implementation manner of the second aspect, the access device is an optical line terminal OLT, and a digital subscriber line access complex A DSLAM or a multi-service access node MSAN.

A third aspect of the present invention provides a dialing system, including an access device, a terminal device, and a broadband access server BRAS, wherein the terminal device is connected to the BRAS through the access device, where

The access device is configured to send a probe packet to the network, obtain a media access control MAC address of the online BRAS, and save the acquired MAC address of the BRAS in the BRAS list; and the BRAS corresponding to the MAC address in the BRAS list Sending a handshake message to obtain the current state of the corresponding BRAS; obtaining the MAC address of the BRAS in the offline state, obtaining the attribution from the correspondence between the MAC address of the BRAS and the MAC address of the terminal device and the session session ID The MAC address and the session ID of the terminal device of the BRAS; and sending the offline notification message to the corresponding terminal device according to the obtained MAC address and the session ID of the terminal device;

The terminal device is configured to perform dialing after receiving the offline notification message of the access device.

In a first possible implementation manner of the third aspect, the access device is further configured to monitor a dialing process of the terminal device to the BRAS, and obtain a MAC address of the terminal device and a MAC address of the BRAS from the dialing process of the terminal device. And the session ID, and the MAC address of the terminal device, the MAC address of the BRAS, and the session ID are associated with each other and saved to the access device.

The technical effect of the present invention is that the access device sends a probe packet to the network, obtains the MAC address of the online BRAS, and stores the acquired MAC address of the BRAS in the BRAS list, and the BRAS corresponding to the MAC address in the BRAS list. Send a handshake packet to obtain whether the corresponding BRAS is offline. After obtaining the MAC address of the BRAS in the offline state, obtain the attribution from the MAC address of the BRAS and the MAC address of the terminal device and the session ID. The MAC address and the session ID of the terminal device of the offline BRAS are sent to the corresponding terminal device according to the obtained MAC address and the session ID of the terminal device, so as to make the corresponding end The terminal device performs dialing. By detecting whether the BRAS is online, when the BRAS is offline, the offline notification message is sent to the terminal device connected to the BRAS, so that the terminal device can automatically perform the dialing process again, thereby effectively reducing the number of times. Service interruption time caused by offline failure due to BRAS failure or connection failure.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a schematic structural diagram of a network to which a dialing method of a terminal device of the present invention is applied;

2 is a flowchart of an embodiment of a dialing method of a terminal device according to the present invention;

3 is a flowchart of another embodiment of a dialing method of a terminal device according to the present invention;

4 is a schematic structural diagram of an embodiment of an access device according to the present invention;

FIG. 5 is a schematic structural diagram of another embodiment of an access device according to the present invention.

Specific embodiment

1 is a schematic structural diagram of a network to which a dialing method of a terminal device of the present invention is applied. As shown in FIG. 1, the network includes a BRAS 11, an access node (Access Node; abbreviated as AN) 12, and a terminal device 13. The BRAS 11 may have one or more interfaces, and each interface has a connection relationship with an AN 12. The AN 12 can be connected to the interfaces of multiple BRASs 11, respectively. The user equipment 13 is connected to only one AN 12 during the same online procedure.

In addition, the AN 12 may include a Digital Subscriber Line Access Multiplexer (DSLAM) or a Multi-Service Access Node (MSAN). The user equipment 13 may include a PPPoE client device such as a home gateway, Modern, STB, or PC. 2 is a flowchart of an embodiment of a dialing method of a terminal device according to the present invention. In combination with the structure of the network shown in FIG. 1 , as shown in FIG. 2 , the execution body of the embodiment is an access node, and the method is Includes:

Step 101: The access device sends a probe packet to the network, obtains a Media Access Control (MAC) address of the online BRAS, and saves the obtained MAC address of the BRAS in the BRAS list.

Step 102: The access device sends a handshake packet to the BRAS corresponding to the MAC address in the BRAS list, to obtain the current state of the corresponding BRAS. Preferably, the handshake may be performed to the BRAS corresponding to the MAC address of each BRAS in the BRAS list, that is, the handshake message is sent to the BRAS corresponding to the MAC address of each BRAS, to obtain a corresponding correspondence. Whether the BRAS is offline. The first predetermined time may be configured according to actual conditions. For example, the first predetermined time may be 0.5 seconds, that is, every 0.5 seconds, a handshake "3⁄4 text" is sent to each BRAS.

More preferably, an Access Node Control Protocol (ANCP), a Packet Internet Groper (PING), and an Address Resolution Protocol (ARP) may be used. , broadcast PADI or unicast PADI mode, respectively, handshake with the BRAS corresponding to the MAC address of each BRAS in the BRAS list.

Step 103: The access device acquires the MAC address of the BRAS in the offline state, and obtains the MAC address of the terminal device belonging to the BRAS in the offline state from the correspondence between the MAC address of the BRAS and the MAC address of the terminal device and the session session ID. And the Session ID.

In this embodiment, it should be noted that when the number of consecutive handshake timeouts with the BRAS is equal to a predetermined threshold, that is, the BRAS is offline, from the MAC address of the BRAS and the MAC address of the terminal device and the Session ID. Obtain the MAC address and Session ID of the terminal device belonging to the BRAS in the offline state.

In this embodiment, for example, when the predetermined threshold is 3, the access device sends a handshake message to each BRAS in the BRAS list every first predetermined time, if not received within the time threshold. The response message returned by a certain BRAS is regarded as a handshake timeout for the BRAS. If the BRAS has 3 consecutive handshake timeouts, the BRAS is considered to be offline (fault or connection failure). The MAC address of the terminal device connected to the BRAS and the assigned session ID.

Step 104: The access device sends an offline notification message to the corresponding terminal device according to the obtained MAC address and the session ID of the terminal device, so that the corresponding terminal device performs dialing.

In this embodiment, the offline notification message is a PPPOE Active Discovery Terminal (PADT) message, or a PADX message, or a PADT message carrying an immediate redial identification. Among them, the PADX message generally refers to the PADT message, and uses a new code value to construct a new message with a specific meaning. Compared with the terminal device, after receiving the PADT packet, the terminal device will delay the dialing process for a few seconds. After receiving the PADX packet, the terminal device will perform the dialing process immediately, so the terminal device receives the PADX packet. After, no need Waiting can re-do the dialing process, and more effectively shorten the mid-business interruption time.

In this embodiment, the access device sends a probe packet to the network, obtains the MAC address of the online BRAS, and stores the obtained MAC address of the BRAS in the BRAS list, and sends the BRAS to the BRAS corresponding to the MAC address in the BRAS list. After the handshake is performed, the current state of the corresponding BRAS is obtained, and after obtaining the MAC address of the BRAS in the offline state, the attribution is obtained from the correspondence between the MAC address of the BRAS and the MAC address of the terminal device and the session ID. The MAC address and the session ID of the terminal device of the BRAS are sent to the corresponding terminal device according to the obtained MAC address and the session ID of the terminal device, so that the corresponding terminal device performs dialing, because it is determined whether the BRAS is online or not. When the BRAS is found to be offline, the offline notification message is sent to the terminal device connected to the BRAS, so that the terminal device can automatically perform the dialing process again, thereby effectively reducing the offline caused by the BRAS failure or the connection failure. Business interruption time.

FIG. 3 is a flowchart of another embodiment of the dialing method of the terminal device according to the present invention. On the basis of the embodiment shown in FIG. 1 , as shown in FIG. 2 , a specific implementation manner in step 101 is as follows:

Step 101: The access device sends a PPPOE Active Discovery Initiation (PADIE) to the BRAS in the network to send a PPPOE Active Discovery Initiation (PADI).

Step 101b: The access device receives a PPPOE Active Discovery Offer (PADO) packet of the BRAS, obtains the MAC address of the BRAS from the PADO packet, and stores the obtained MAC address of the BRAS. Go to the BRAS list.

In this embodiment, preferably, the access device may send a PADI message to the BRAS in the network every second predetermined time. The second predetermined time may be configured according to actual conditions, for example, the second predetermined time may be 10 seconds.

In this embodiment, the receiving device sends a PADI message to the upstream direction (the PADI message is a broadcast message), and all received PADI BRASs respond to a PADO message. When the PADO message is received, the receiving device can The MAC address of the BRAS sent by the PADO message is obtained from the PADO message, thereby detecting which online BRASs are on the network. The MAC address can be used as the unique identifier of the BRAS.

Preferably, after step 101b, before step 102, the method may further include:

Step 101c: The access device monitors the dialing process of the terminal device to the BRAS, and the slave terminal sets The MAC address of the terminal device, the MAC address of the BRAS, and the session ID are obtained in the backup dialing process, and the MAC address of the terminal device, the MAC address of the BRAS, and the session ID are stored in the corresponding relationship.

More preferably, a specific implementation of step 101c is:

The access device receives the PPPoE Active Discovery Session-Confirmation (PADS) of the BRAS;

The access device stores the MAC address of the terminal device in the PADS packet, the MAC address of the BRAS, and the session ID in a corresponding relationship on the access device.

In this embodiment, for each terminal device, when the terminal device performs dialing, the first responding BRAS is selected as an authentication server and connected thereto. At the same time, since the terminal device needs to pass the AN when dialing, the AN can listen to the PPPOE Active Discovery Session-Confirmation (PADS) message returned by the authentication server to the terminal device, thereby recording the basic of the user. The information, that is, the MAC address of the terminal device and the session ID, establishes a mapping relationship between the MAC address of the terminal device and the session ID and the MAC address of the BRAS.

It should also be noted that step 101 may also have another specific implementation as follows:

The access device sends an Address Resolution Protocol (ARP) packet to the BRAS corresponding to the IP address according to the pre-configured BRAS IP address;

It will be understood by those skilled in the art that all or part of the steps of implementing the above method embodiments may be performed by hardware associated with the program instructions. The aforementioned program can be stored in a computer readable storage medium. The program, when executed, performs the steps including the foregoing method embodiments; and the foregoing storage medium includes: a medium that can store program codes, such as a ROM, a RAM, a magnetic disk, or an optical disk.

4 is a schematic structural diagram of an embodiment of an access device according to the present invention. As shown in FIG. 4, the access device of this embodiment includes a first transceiver 21, a second transceiver 22, a processor 23, and a third transceiver. And a memory 25, wherein the first transceiver 21 is configured to send a probe message to the network, obtain a MAC address of the online BRAS, and save the acquired MAC address of the BRAS in the BRAS list; the second transceiver 22 is configured to: Sending a handshake message to the BRAS corresponding to the MAC address in the BRAS list to obtain the current state of the corresponding BRAS; the processor 23 is configured to acquire the BRAS in the offline state. The MAC address, the MAC address of the terminal device belonging to the BRAS in the offline state is obtained from the MAC address of the BRAS and the MAC address of the terminal device and the session session ID, and the offline notification message is sent to the corresponding terminal device. So that the corresponding terminal device dials; the memory 25 is used to store the BRAS list.

The access device in this embodiment can perform the technical solution of the method embodiment shown in FIG. 2, and the implementation principle is similar, and details are not described herein again.

In addition, the first transceiver 21, the second transceiver 22, and the third transceiver 24 may be the same transceiver or three independent transceivers. The processor 23 can be a central processing unit (CPU) or the like. The specific form of the memory 25 may be RAM, ROM, flash memory, or the like. It should be noted that, when the access device is a DSLAM, the transceiver may be a joint transceiver; when the access device is an OLT, the transceiver may be an optical transceiver; when the access device is an MSAN, The transceiver may be an Ethernet Switching Chip (LSW), a Field-Programmable Gate Array (FPGA), or a Network Processor (abbreviation: NP).

In this embodiment, the access device sends a probe packet to the network, obtains the MAC address of the online BRAS, and stores the obtained MAC address of the BRAS in the BRAS list, and sends the BRAS to the BRAS corresponding to the MAC address in the BRAS list. The handshake message is used to obtain whether the corresponding BRAS is offline. When the MAC address of the BRAS in the offline state is obtained, the MAC address of the BRAS and the MAC address of the terminal device of the BRAS and the session ID are obtained according to the acquired terminal device. The MAC address and the session ID send the offline notification message to the corresponding terminal device, so that the corresponding terminal device performs dialing. Since the BRAS is found to be online, the BRAS is actively sent to the terminal device connected to the BRAS when the BRAS is offline. The offline notification message enables the terminal device to automatically perform the dialing process again. Therefore, the service interruption time caused by the offline failure due to the BRAS failure or the connection failure is effectively reduced.

FIG. 5 is a schematic structural diagram of another embodiment of an access device according to the present invention. On the basis of the foregoing embodiment shown in FIG. 5, as shown in FIG. 5, the first transceiver 21 specifically includes: a data transmitter 211 and data. a receiver 212; wherein, the data transmitter 211 is configured to send a PADI message to the BRAS in the network; the data receiver 212 is configured to receive the PADO message of the BRAS, and obtain the PADO message from the PADO message. The MAC address of the BRAS stores the acquired MAC address of the BRAS into the BRAS list. Alternatively, the data transmitter 211 is configured to send an address resolution protocol ARP message to the BRAS corresponding to the IP address according to the IP address of the pre-configured BRAS; the data receiver 212 is configured to receive the BRAS.

The ARP response packet obtains the MAC address of the BRAS corresponding to the IP address from the ARP response packet, and stores the obtained MAC address in the BRAS list.

Preferably, the second transceiver 22 is further configured to forward the packet of the terminal device to the BRAS dialing process;

The processor 23 is further configured to obtain the MAC address of the terminal device, the MAC address of the BRAS, and the session ID from the dialing process of the terminal device, and save the correspondence between the MAC address of the acquiring terminal device, the MAC address of the BRAS, and the Session ID to In the memory 25.

More preferably, the access device is an OLT, a DSLAM or an MSAN.

The invention also provides a dialing system, comprising: an access device, a terminal device, and a BRAS. The terminal device is connected to the BRAS through the access device, where the access device is configured to send the probe packet to the network, obtain the media access control MAC address of the online BRAS, and save the obtained MAC address of the BRAS in the BRAS list. Sending a handshake message to the BRAS corresponding to the MAC address in the BRAS list to obtain whether the corresponding BRAS is offline; obtaining the MAC address of the BRAS in the offline state, the MAC address of the BRAS, the MAC address of the terminal device, and the session session. Obtaining a MAC address and a session ID of the terminal device belonging to the offline BRAS; and sending the offline notification message to the corresponding terminal device according to the obtained MAC address and the session ID of the terminal device;

In addition, the access device is further configured to monitor the dialing process of the terminal device to the BRAS, obtain the MAC address of the terminal device, the MAC address of the BRAS, and the session ID from the dialing process of the terminal device, and obtain the terminal device. The MAC address, the MAC address of the BRAS, and the session ID are stored in the corresponding relationship and saved to the access device.

It should be noted that the above embodiments are merely illustrative of the technical solutions of the present invention, and are not intended to be limiting; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art The technical solutions described in the foregoing embodiments may be modified, or some or all of the technical features may be equivalently replaced; and the modifications or substitutions do not deviate from the technical solutions of the embodiments of the present invention. range.

Claims

claims

1. A dialing method for terminal equipment, characterized in that it includes:

The access device sends a detection message to the network to obtain the media access control MAC address of the online broadband access server BRAS, and saves the obtained BRAS MAC address in the BRAS list;

The access device sends a handshake message to the BRAS corresponding to the MAC address in the BRAS list to obtain the current status of the corresponding BRAS;

The access device obtains the MAC address of the BRAS in the offline state, and obtains the MAC address of the terminal device belonging to the offline BRAS from the corresponding relationship between the MAC address of the BRAS, the MAC address of the terminal device, and the session ID. Session ID;

The access device sends an offline notification message to the corresponding terminal device according to the obtained MAC address and Session ID of the terminal device, so that the corresponding terminal device dials.

2. The method according to claim 1, characterized in that, the access device sends a detection message to the network, obtains the media access control MAC address of the online broadband access server BRAS, and uses the obtained MAC address of the BRAS Specific items saved in the BRAS list include:

The access device sends an Ethernet Bearer Point-to-Point Protocol PPPoE activation discovery initiation packet PADI message to the BRAS in the network;

The access device receives the PPPoE activation discovery phase service message PADO message of the BRAS, obtains the MAC address of the BRAS from the PADO message, and stores the obtained MAC address of the BRAS into the BRAS list.

3. The method according to claim 1, characterized in that: the access device sends a detection message to the network, obtains the media access control MAC address of the online broadband access server BRAS, and uses the obtained MAC address of the BRAS Saved in the BRAS list, specifically including:

The access device sends an Address Resolution Protocol ARP message to the BRAS corresponding to the IP address according to the preconfigured IP address of the BRAS;

The access device receives the ARP response message of the BRAS, obtains the MAC address of the BRAS corresponding to the IP address from the ARP response message, and stores the obtained MAC address in the BRAS list.

4. The method according to claim 1, characterized in that: the access device sends a detection message to the network, obtains the media access control MAC address of the online broadband access server BRAS, and uses the obtained MAC address of the BRAS After saving in the BRAS list, the method also includes: The access device monitors the dialing process of the terminal device to the BRAS, obtains the MAC address of the terminal device, the MAC address of the BRAS, and the Session ID from the dialing process of the terminal device, and obtains the MAC address of the terminal device and the MAC of the BRAS. The address, and Session ID form a corresponding relationship and are saved on the access device.

5. The method according to claim 4, characterized in that, the access device monitors the dialing process of the terminal device to the BRAS, and obtains the MAC address of the terminal device, the MAC address of the BRAS, and the MAC address of the terminal device from the dialing process of the terminal device. And Session ID, including:

The access device receives the Ethernet Bearer Point-to-Point Protocol PPPoE activation discovery session confirmation packet PADS message of the BRAS;

The access device forms a corresponding relationship between the MAC address of the terminal device, the MAC address of the BRAS and the Session ID in the PADS message and stores them on the access device.

6. An access device, characterized by including:

The first transceiver is used to send detection messages to the network, obtain the media access control MAC address of the online broadband access server BRAS, and save the obtained MAC address of the BRAS in the BRAS list;

The second transceiver is configured to send a handshake message to the BRAS corresponding to the MAC address in the BRAS list to obtain the current status of the corresponding BRAS;

The processor is configured to obtain the MAC address of the BRAS in the offline state, and obtain the MAC address of the terminal device belonging to the offline BRAS from the corresponding relationship between the MAC address of the BRAS and the MAC address of the terminal device and the Session ID. Session ID;

The third transceiver is used to send an offline notification message to the corresponding terminal device based on the obtained MAC address and Session ID of the terminal device, so that the corresponding terminal device can dial;

Memory, used to store the BRAS list.

7. The access device according to claim 6, characterized in that the first transceiver specifically includes:

A data sender, configured to send an Ethernet bearer point-to-point protocol PPPoE activation discovery initiation packet PADI message to the BRAS in the network;

The data receiver is configured to receive the PPPoE activation discovery phase service message PADO message of the BRAS, obtain the MAC address of the BRAS from the PADO message, and store the obtained MAC address of the BRAS in the BRAS list.

8. The access device according to claim 7, wherein the first transceiver specifically includes:

The data sender is used to send an Address Resolution Protocol ARP message to the BRAS corresponding to the IP address according to the pre-configured IP address of the BRAS;

The data receiver is configured to receive the ARP response message of the BRAS, obtain the MAC address of the BRAS corresponding to the IP address from the ARP response message, and store the obtained MAC address in the BRAS list.

9. The access device according to claim 7, characterized in that,

The second transceiver is also used to forward the message of the dialing process of the terminal device to the BRAS; the processor is also used to obtain the MAC address of the terminal device, the MAC address of the BRAS from the dialing process of the terminal device, and Session ID: obtain the MAC address of the terminal device, the MAC address of the BRAS, and the Session ID to form a corresponding relationship and save them in the memory.

10. The access device according to any one of claims 6 to 9, characterized in that the access device is an optical line terminal OLT, a digital subscriber line access multiplexer DSLAM or a multi-service access node MSAN.

11. A dial-up system, including an access device, a terminal device, and a broadband access server BRAS. The terminal device is connected to the BRAS through the access device, characterized in that,

The access device is used to send detection messages to the network, obtain the media access control MAC address of the online BRAS, and save the obtained MAC address of the BRAS in the BRAS list; to the BRAS corresponding to the MAC address in the BRAS list. Send a handshake message to obtain the current status of the corresponding BRAS; obtain the MAC address of the offline BRAS, and obtain the offline BRAS from the corresponding relationship between the BRAS MAC address, the MAC address of the terminal device, and the session ID. The MAC address and Session ID of the terminal device of the BRAS; and sends an offline notification message to the corresponding terminal device based on the obtained MAC address and Session ID of the terminal device;

The terminal device is used to dial after receiving the offline notification message from the access device.

12. The dialing system according to claim 10, characterized in that the access device is also used to monitor the dialing process of the terminal device to the BRAS, and obtain the MAC address and BRAS of the terminal device from the dialing process of the terminal device. The MAC address and Session ID of the terminal device are obtained, and a corresponding relationship between the MAC address of the terminal device, the MAC address of the BRAS and the Session ID is obtained and stored on the access device.