CN101572928B

CN101572928B - Switching method, communication system and associated equipment

Info

Publication number: CN101572928B
Application number: CN2008100944737A
Authority: CN
Inventors: 胡伟华
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2008-04-30
Filing date: 2008-04-30
Publication date: 2011-05-04
Anticipated expiration: 2028-04-30
Also published as: CN101572928A; WO2009132550A1

Abstract

The embodiment of the invention discloses a switching method, a communication system and associated equipment, which are used for realizing lossless switching of data when a service gateway (SGW) changes. The method comprises: sending an end marking package to a target side access element location when an access network changes and a source side SGW changes so as to facilitate the target side access element location of distributing down data from a target side core network according to the indication of the end marking package. The embodiment of the invention also provides the communication system, a service gateway and a packet data network gateway.

Description

Switching method, communication system and related equipment

Technical Field

The present invention relates to the field of communications, and in particular, to a handover method, a communication system, and related devices.

Background

In the switching process of an access network element inside the current Evolved Packet network (EPS), in order to ensure that user data is not lost, i.e. lossless, in the switching process. The access network of the source side network forwards the downlink data which is not sent to the terminal to the target side network, and the downlink data is sent to the terminal by the access network of the target network; meanwhile, in order to ensure that the downlink data is transmitted to the terminal as orderly as possible, the access network of the target network needs to distinguish the downlink data transmitted by the source side network from the downlink data transmitted by the core network of the target network, and ensure that the data transmitted by the source side network is firstly transmitted to the terminal and then the received downlink data from the user plane of the core network of the target network is transmitted as possible. In order to help the access network to implement the above downlink data ordering, the access network provides a requirement for the core network, that is, the access network needs to know when the downlink data forwarded by the source side network is finished, so that a core network Service Gateway (SGW) is required to issue a finish tag packet to the target side access network, and the target side access network receives the finish tag packet, knows that the data forwarded by the source side network is finished, and can issue the downlink data received from the target core network to the terminal.

The method requires that the SGW issues an end marker packet to the target side access network, the method can be implemented if the core network service gateway is kept unchanged, and when switching actually occurs, the core network service gateway or the mobility management network element may be changed, and the switching occurring under the condition also has the requirement of data loss prevention. Meanwhile, because different Access technologies of a GSM/EDGE Radio Access Network (GERAN), a UMTS Terrestrial Radio Access Network (UTRAN), and an Evolved UMTS Terrestrial Radio Access Network (EUTRAN) exist inside a third Generation partnership project (3GPP, 3rd Generation partnership project), the handover may be divided into handover inside the same Access technology and handover between different Access technologies, and the handover between the Evolved Access Network EUTRAN and different Access technologies of a second Generation/third Generation Network inevitably causes a change in SGW of a control plane. Therefore, in the prior art, there is no scheme for realizing lossless transmission of data in case of switching with a changed SGW.

Disclosure of Invention

The embodiment of the invention provides a switching method, a communication system and related equipment, which can realize lossless data transmission under the condition that SGW changes.

The switching method provided by the embodiment of the invention comprises the following steps: and when the access network is switched and the source side SGW is switched to the target side SGW, sending an end marking packet to a target side access network element so as to facilitate the target side access network element to issue downlink data from the target side core network to the user equipment according to the indication of the end marking packet.

The communication system provided by the embodiment of the invention comprises: the network side core network equipment is used for sending an end marking packet to a target side access network element after the access network switching occurs and the source side service gateway SGW is switched to the target side SGW; and the target side access network element is used for receiving the end mark packet sent by the network side core network equipment and sending downlink data from the target side core network to the user equipment after receiving the end mark packet.

The service gateway provided by the embodiment of the invention comprises: the triggering unit is used for triggering the sending unit when preset sending conditions are met after the access network switching occurs and the source side SGW is switched to the target side SGW; and a sending unit, configured to send the end marker packet to a target side access network element according to the trigger of the trigger unit, where the end marker packet is used to instruct the target side access network element to issue downlink data from a target side core network to user equipment according to the instruction of the end marker packet.

The packet data network gateway provided by the embodiment of the invention comprises: an end mark packet triggering unit, configured to trigger the end mark packet sending unit when a preset sending condition is met; and an end marker packet sending unit, configured to send an end marker packet to a source side access network element according to the trigger of the end marker packet triggering unit, where the end marker packet is used to instruct the target side access network element to issue downlink data from a target side core network to a user equipment according to the instruction of the end marker packet.

According to the technical scheme, the embodiment of the invention has the following advantages:

in this embodiment, after the source-side SGW is switched to the target-side SGW, there are two data transmission paths of the data gateway PGW, one is an old bearer path for transmitting data to the source-side SGW, and the other is a new bearer path for transmitting data to the target-side SGW, after the PGW updates the bearer, the PGW does not transmit data to the source-side SGW any more, but transmits the data to the target-side SGW, and in order to ensure the data order, the target-side access network element needs to transmit data from the source-side before transmitting data from the target-side, in an embodiment of the present invention, the network-side core network device transmits an end marker packet to the target-side access network element, where the end marker packet is used to instruct the target-side access network element to issue downlink data from the target-side core network to the user equipment, so even if the serving gateway changes, the target-side access network element can still obtain the end marker packet from the network-side core network device, to confirm that the source side data has been sent, the data from the target side can be forwarded, thus enabling lossless transmission of data to be achieved even if the SGW changes.

Drawings

FIG. 1 is a flowchart illustrating a handover method according to a first embodiment of the present invention;

FIG. 2 is a flowchart illustrating a handover method according to a second embodiment of the present invention;

FIG. 3 is a flowchart illustrating a handover method according to a third embodiment of the present invention;

FIG. 4 is a flowchart illustrating a handover method according to a fourth embodiment of the present invention;

FIG. 5 is a flowchart illustrating a handover method according to a fifth embodiment of the present invention;

FIG. 6 is a flowchart illustrating a handover method according to a sixth embodiment of the present invention;

FIG. 7 is a diagram of a communication system in an embodiment of the invention;

FIG. 8 is a diagram of a service gateway in an embodiment of the present invention;

fig. 9 is a schematic diagram of an embodiment of a packet data network gateway according to the embodiment of the present invention.

Detailed Description

The embodiment of the invention provides a switching method, a communication system and related equipment, which are used for realizing lossless switching of data under the condition that SGW changes.

The embodiment of the switching method in the embodiment of the invention comprises the following steps:

and when the access network is switched and the source side SGW is switched to the target side SGW, sending an end marking packet to a target side access network element so as to facilitate the target side access network element to issue downlink data from a target side core network to user equipment according to the indication of the end marking packet.

It should be noted that after the location of the ue changes, the ue may enter a coverage of another network from a coverage of one network, at this time, access network handover is required, a network that provides services for the ue before handover is referred to as a source network, a network that provides services for the ue after handover is referred to as a target network, an SGW that originally provides services for the ue in the source network becomes a source-side SGW, a network after handover is referred to as a target-side network, and an SGW that provides services for the ue in the target-side network becomes a target-side SGW.

The network side core network device in the foregoing embodiment may be a source side SGW, a target side SGW, or a Packet data network Gateway (PGW), and specifically, the timing and the sending mode for sending the end marker Packet to the target side access network element are described in the following examples:

firstly, a source side SGW sends an end marker packet:

in this embodiment, after determining that the source-side data transmission is completed, the source-side SGW transmits an end marker packet to the target-side access network element through the source-side access network element, so as to instruct the target-side access network element to issue downlink data from the target-side core network to the user equipment.

In this embodiment, according to an EPS network (handover in which a core network mobility management element is not changed inside) and a 3GPP network (handover in which a core network mobility management element is changed inside), the following two embodiments can be continuously divided:

A. EPS network (handover without changing core network mobility management network elements inside):

referring to fig. 1, a first embodiment of a handover method according to the embodiment of the present invention includes:

101. the user equipment transmits uplink data and downlink data with the PGW through the source base station;

in this embodiment, an EPS network is used, and the access network element takes a base station as an example for description.

102. The source base station and the target base station negotiate to carry out switching;

when the user equipment meets the handover condition (for example, the user equipment moves from the coverage area of one network to the coverage area of another network), a handover preparation process is performed between the source base station and the target base station, and the user equipment is instructed to switch to access the target base station. The specific flow is not limited.

103. The source base station transmits downlink data which is not transmitted to the user equipment to the target base station;

104. the target base station sends the received forwarding data to the user equipment;

105. the user equipment sends uplink data to the PGW through the target base station;

106. the target base station sends a path switching request to a Mobile Management Entity (MME);

in this embodiment, the target base station sends a path switching request to the MME to notify the MME that the user equipment changes a cell, where the path switching request includes global cell identification information of the target cell, and the MME may determine, according to the global cell identification information, an SGW serving the user equipment, that is, select a new SGW to provide service for the user equipment.

107. The MME sends a bearer creation request to a target side SGW;

the MME sends a bearer creation request to a target side SGW (namely a selected new SGW), wherein the request comprises bearer context information of a user and comprises user plane resource information distributed by a core network user plane anchor point PGW for receiving uplink data;

and after receiving the bearer creation request, the target side SGW allocates the user plane resources for receiving the uplink data.

108. The target side SGW sends a bearer updating request to the PGW;

and the target side SGW allocates the user plane resource for receiving the downlink data and sends an update bearing request message to the PGW, wherein the message comprises the user plane information for receiving the downlink data.

And the PGW updates the bearer context of the user after receiving the bearer updating request message, stores the user plane information, starts to send downlink user data received from the data source to the target side SGW, and forwards the downlink user data to the target side base station through the target side SGW.

109. The PGW returns an update bearer response message to the SGW;

the update bearer response message may include user plane information allocated by the PGW for receiving uplink data.

110. The target side SGW sends a bearer establishing response message to the MME;

and the target SGW sends a bearer establishing response message to the MME, wherein the message contains the user plane resource information which is distributed by the target SGW and used for receiving the uplink data.

The MME starts a timer after receiving the bearer creation response message, where the timer is used to determine whether source-side data that is sent to the source-side SGW before the PGW is sent by the target-side access network element, and specifically, a person skilled in the art may have various implementation manners in a process of determining whether the source-side data is sent by using the timer, where the implementation manners are not limited herein, for example, a timing experience value of a timer may be estimated according to an average sending rate of data, and when the experience value is finished, it may be determined that the source-side data is sent, and in addition, the person skilled in the art may also use other technical means besides the timer to determine whether the source-side data is sent, which is not described herein again.

111. The PGW sends downlink data to the user equipment through the target side base station;

112. the MME sends a path switching confirmation message to a target side base station;

and the MME sends a path switching request confirmation message to the target side base station to confirm that the switching path is successful, wherein the message comprises user plane resource information distributed by the target side SGW for receiving uplink data.

And after receiving the path switching confirmation message, the target side base station forwards the uplink data from the user equipment by using the user plane resource information in the message.

113. The user equipment sends uplink data to the PGW through the target side base station;

114. the target side base station informs the source side base station of successful switching and requires the source side base station to release resources;

115. the MME sends a bearer deletion request to the source side SGW;

when the timer started by the MME in step 110 is overtime, that is, after the MME confirms that the sending of the source-side data is completed, the MME sends a bearer deletion request message to the source-side SGW, where the bearer deletion request message carries indication information for indicating that the source-side SGW has performed the path switch and that the source-side data has been already issued, or directly indicates that the source-side SGW needs to issue an end marker packet, or may even specify a specific bearer list that the source-side SGW needs to issue an end marker.

In this embodiment, the timer started by the MME is provided with an overflow threshold, where the threshold may be an empirical value, and when the timer overflows, it may be considered that data on the source side has been sent completely.

It should be noted that, in this embodiment, the data of the source side refers to data that is delivered by the PGW through the source-side SGW, and the data of the target side refers to data that is delivered by the PGW through the target-side SGW, that is, after the SGW is switched, when the PGW delivers the data, there are two paths, one of which is a path where the source-side SGW is located and is referred to as a source-side path, and the other is a path where the target-side SGW is located and is referred to as a target-side path, when the PGW receives an update bearer instruction, the delivery of the data from the source-side path is stopped, and the data is delivered by the target-side path, and for the PGW, the source-side data has already been delivered, but since the data delivered by the PGW through the source-side path to the SGW may still be in the route of the source side before receiving the update bearer instruction, the MME needs to start the timer, and when, the source-side SGW has already issued the source-side data, so a bearer deletion request carrying the indication information may be sent to the source-side SGW.

116. The source side SGW feeds back a bearer deletion response message to the MME;

117. a source side SGW sends an end marking packet to a source side base station;

118. the source side base station transmits an end mark packet to the target side base station, and the target side base station can know that downlink data from a target side core network can be transmitted to the user equipment after receiving the end mark packet.

It should be noted that there is no fixed execution sequence between step 116 and step 117, and after the end flag packet is sent, the source-side SGW releases its own user plane resource.

In the above embodiment, the bearer deletion request sent by the MME to the source-side SGW carries indication information, and it can be understood that, in practical applications, the source-side SGW may directly issue the end marker packet before the bearer deletion request sent by the MME is received and the user plane resource is released, or determine whether the end marker packet needs to be issued according to the qos requirement of the user bearer context by itself, for example, it is known that data required on a certain bearer is not damaged according to the qos requirement, and the source-side SGW may issue the end marker packet on the bearer path.

It should be further noted that, the process of the source-side SGW issuing the end marker packet before releasing the user plane resource may also adopt the following manner:

the MME sends a bearer deletion request to the source-side SGW without waiting for the timeout of the timer after step 110, where the bearer deletion request does not carry indication information, the source-side SGW starts a timer after receiving the bearer deletion request, and after the timer reaches a preset time, the SGW confirms that the source-side data is sent, that is, sends an end marker packet, and releases the user plane resources.

B. 3GPP network (handover of internal change core network mobility management network element):

referring to fig. 2, a second embodiment of a handover method according to the embodiment of the present invention includes:

201. the source side access network element decides to initiate the switching;

202. the source side access network element sends a switching request message to the source side mobile management network element;

the source side access network element requests the source side mobile management network element to start switching and indicates the bearer context which needs data forwarding.

203. The source side mobile management network element sends a forwarding switching request to a target side mobile management network element;

the source side mobile management network element selects a target side mobile management network element and sends a forward switching request message, wherein the message comprises the mobile management context of the user and the user plane bearing context information.

204. Allocating resources by the target network;

and the target side mobility management network element determines whether the current source side SGW can continuously serve the user equipment, and if not, reselects a new SGW, namely the target side SGW.

And the target side mobile management network element controls the target network to allocate corresponding bearing resources and data forwarding resources for the switching user.

205. The target side mobile management network element feeds back a forward switching response message to the source side mobile management network element;

206. a source side mobile management network element sends a bearer creation request to a source side SGW;

and if the data forwarding adopts indirect data forwarding, the source side mobile management network element interacts with the source side SGW to construct an indirect data forwarding channel.

207. The source side SGW feeds back a bearer establishing response to the source side mobile management network element;

208. the source side mobile management network element sends a switching command to the source side access network element, and the switching command is used for indicating the source network to start switching;

209. the source side access network element sends a switching command to the user equipment for informing the UE of starting switching;

210. the source side access network element starts to forward data to a target network;

212. the target side access network element sends a switching notice to the target side mobility management network element;

and after the target side access network element confirms the access of the user equipment, sending a switching notice to the target side mobility management network element.

213. The target side mobile management network element sends a forward switching completion message to inform the source side mobile management network element;

214. the source side mobile management network element returns a forward switching completion confirmation message to the target side mobile management network element;

215. the target side mobile management network element sends a load updating request message to a target side SGW to update user plane load information;

216. the target side SGW sends a bearer updating request to the PGW;

and the target side SGW initiates a bearer updating process to update bearer information on the PGW, wherein the bearer information comprises user plane bearer information, the type of an access network of a user and the like.

217. The PGW feeds back an update bearing response to the target side SGW;

218. the target side SGW returns an update bearing response message to the target side mobile management network element;

219. a source side mobile management network element sends a bearer deletion request to a source side SGW;

if the source side mobility management network element knows that the SGW is changed from the received forward switching completion message, the source side mobility management network element sends a bearer deletion request message to the source side SGW after receiving the forward switching completion message from the target network, wherein the message contains indication information used for indicating that the source side SGW has path switching and the source side data is already issued, or displaying a bearer list indicating that an end mark packet needs to be issued, or even indicating that the source side SGW needs to issue the end mark.

In this embodiment, the source-side mobility management element may also send the bearer deletion request message after the timer expires by setting the timer.

It should be noted that, in this embodiment, the data of the source side refers to data that is delivered by the PGW through the source-side SGW, and the data of the target side refers to data that is delivered by the PGW through the target-side SGW, that is, after the SGW is switched, when the PGW delivers the data, there are two paths, one of which is a path where the source-side SGW is located and is referred to as a source-side path, and the other is a path where the target-side SGW is located and is referred to as a target-side path, when the PGW receives an update bearer instruction, the delivery of the data from the source-side path is stopped, and the data is delivered by the target-side path, so for the PGW, the source-side data has already been delivered, but since the data delivered by the PGW through the source-side path to the SGW may still be in the way of the source side before the update bearer instruction is received, the source-side mobility management needs to start the network, the source-side SGW has already issued the source-side data, so a bearer deletion request carrying the indication information may be sent to the source-side SGW.

220. The source side SGW sends a bearer deletion response to the source side mobile management network element;

221. the source side SGW sends an end marking packet to a source side access network element;

222. the source side access network element transmits the end marking packet to the target side access network element, and the target side access network element can start to issue downlink data from a target side core network to the user equipment after receiving the end marking packet.

It should be noted that there is no fixed execution sequence between step 220 and step 221, and after the end marker packet is sent, the source-side SGW releases its own user plane resource.

In the foregoing embodiment, the bearer deletion request sent by the source-side MME to the source-side SGW carries indication information, and it is understood that, in practical applications, the source-side SGW may always issue the end marker packet before receiving the bearer deletion command sent by the MME and releasing the user plane resource, or determine whether the end marker packet needs to be issued according to the qos requirement of the user bearer context by itself, for example, it is known that data on a certain bearer is not damaged according to the qos requirement, and then the source-side SGW may end the marker packet in the bearer path context.

It should be further noted that, the process of the source-side SGW issuing the end marker packet before releasing the user plane resource may also adopt the following manner: after step 213, the source-side mme sends a bearer deletion request to the source-side SGW without waiting for the timeout of the timer, where the bearer deletion request does not carry indication information, the source-side SGW starts a timer after receiving the bearer deletion request, and when the timer reaches a preset time, the SGW confirms that the source-side data is sent, that is, sends an end marker packet, and releases the user plane resource.

Secondly, sending an end marker packet by the PGW:

in this embodiment, the PGW sends an end marker packet to the target side access network element through the source side access network element, and is configured to instruct the target side access network element to issue downlink data from the target side core network to the user equipment.

In this embodiment, the following two embodiments can be continuously divided according to the EPS network and the 3GPP network:

referring to fig. 3, a third embodiment of a handover method according to the present invention includes:

301. the user equipment transmits uplink data and downlink data with the PGW through the source base station;

302. The source base station and the target base station negotiate to carry out switching;

when the ue meets the handover condition (for example, moves from the coverage of one network to the coverage of another network), a handover preparation procedure is performed between the source base station and the target base station, and the ue is instructed to handover from the source base station to the target base station, where the specific procedure is not limited.

303. The source base station transmits downlink data which is not transmitted to the user equipment to the target base station;

304. the target base station sends the received forwarding data to the user equipment;

305. the user equipment sends uplink data to the PGW through the target base station;

306. the target base station sends a path switching request to the MME;

in this embodiment, the target base station sends a path switching request to the MME, and notifies the MME that the ue changes the cell, where the path switching request includes global cell identification information of the target cell, and the MME may determine, according to the global cell identification information, an SGW serving the ue, and select a new SGW to provide a service for the ue, that is, a target-side SGW.

307. The MME sends a bearer creation request to a target side SGW;

In this embodiment, the bearer creation request sent by the MME to the target SGW includes indication information for indicating that the SGW performs path switching, or directly indicating that the end marker packet needs to be issued, or even indicating that the bearer list of the end marker packet needs to be issued.

308. The target side SGW sends a bearer updating request to the PGW;

In this embodiment, the request for updating the bearer sent by the target SGW includes indication information, which is used to indicate the SGW to perform path switching, or directly indicate that the end marker packet needs to be issued, or even indicate a bearer list that the end marker packet needs to be issued.

309. The PGW returns an update bearer response message to the SGW;

310. The target side SGW sends a bearer establishing response message to the MME;

311. The PGW sends downlink data to the user equipment through the target side base station;

312. the PGW sends an end marker packet to the source side base station;

in this embodiment, the bearer update request received by the PGW from the target SGW includes indication information, which is used to indicate that the SGW performs path switching, or directly indicate that an end marker packet needs to be issued, or even indicate a bearer list that the end marker packet needs to be issued.

The PGW may know, according to the indication information, that the SGW changes, and then stop issuing data from the source-side path, and instead issue data from the target-side path, so that the PGW can know that the source-side data has been issued, and therefore can issue the end marker packet.

It should be noted that, in this embodiment, the data of the source side refers to data that is delivered by the PGW through the SGW of the source side, and the data of the target side refers to data that is delivered by the PGW through the SGW of the target side, that is, after the SGW is switched, when the PGW delivers the data, there are two paths, one of which is a path where the SGW of the source side is located and is called a source side path, and the other is a path where the SGW of the target side is located and is called a target side path.

313. The source side base station transmits an end mark packet to the target side base station, and the target side base station receives the end mark packet, so that the source side base station can know that downlink data from a target side core network can be transmitted to the user equipment;

314. the MME sends a path switching confirmation message to a target side base station;

315. The user equipment sends uplink data to the PGW through the target side base station;

316. the target side base station informs the source side base station of successful switching and requires the source side base station to release resources;

317. the MME sends a bearer deletion request to the source side SGW;

318. and the source side SGW feeds back a bearer deletion response message to the MME.

It should be noted that, after the end marker packet is sent completely, the source-side SGW releases its own user plane resources.

In the above embodiment, the creating bearer request sent by the MME to the target SGW carries the indication information, and the target SGW sends the indication to the PGW through the updating bearer request, it can be understood that, in practical applications, the PGW may always send the end marker packet after receiving the updating bearer request sent by the target SGW without obtaining the indication of the MME, or determine whether the end marker packet needs to be sent by itself according to the qos requirement of the user bearer context, for example, it is known that data required on a certain bearer is not damaged according to the qos requirement, and the PGW may end the marker packet in the bearer path context.

It should be further noted that, the process of issuing the end marker packet by the PGW may also adopt the following manner: because the PGW stops issuing data from the source side path and forwards the data to the target side path when receiving the update bearer indication, the PGW may also directly send the end marker packet without obtaining an indication from the MME, that is, directly perform path switching after receiving the update bearer request sent by the target side SGW, and instead of issuing data from the source side path, forward the data to the target side path, and directly issue the end marker packet from the old bearer path.

referring to fig. 4, a fourth embodiment of a handover method according to the present invention includes:

401. the source side access network element decides to initiate the switching;

402. the source side access network element sends a switching request message to the source side mobile management network element;

403. The source side mobile management network element sends a forwarding switching request to a target side mobile management network element;

404. Allocating resources by the target network;

405. The target side mobile management network element feeds back a forward switching response message to the source side mobile management network element;

406. a source side mobile management network element sends a bearer creation request to a source side SGW;

407. The source side SGW feeds back a bearer establishing response to the source side mobile management network element;

408. the source side mobile management network element sends a switching command to the source side access network element, and the switching command is used for indicating the source network to start switching;

409. the source side access network element sends a switching command to the user equipment for informing the UE of starting switching;

410. the source side access network element starts to forward data to a target network;

412. the target side access network element sends a switching notice to the target side mobility management network element;

413. The target side mobile management network element sends a forward switching completion message to inform the source side mobile management network element;

414. the source side mobile management network element returns a forward switching completion confirmation message to the target side mobile management network element;

415. the target side mobile management network element sends a load updating request message to a target side SGW to update user plane load information;

in this embodiment, the update bearer request carries indication information, where the indication information is used to indicate that the SGW performs path switching, or directly indicate that the end marker packet needs to be issued, or even indicate a bearer list that the end marker packet needs to be issued.

416. The target side SGW sends a bearer updating request to the PGW;

417. The PGW feeds back an update bearing response to the target side SGW;

418. the PGW sends an end marking packet to the source side access network element;

419. The source side access network element transmits an end mark packet to the target side access network element, and the target side access network element receives the end mark packet, so that the situation that downlink data from a target side core network can be issued to user equipment can be known;

420. and the target side SGW returns an update bearing response message to the target side mobile management network element.

In the third and fourth embodiments, the process of sending, by the PGW, the end marker packet to the source side access network element may be: the PGW sends the end marker packet to the source-side SGW, and the source-side SGW forwards the end marker packet to the source-side access network element.

In the above embodiment, the indication information is carried in the update bearer request sent by the target-side mobility management element to the target-side SGW, and then the target-side SGW sends the indication to the PGW through the update bearer request, which can be understood that, in practical applications, the PGW may always send the end marker packet after receiving the update bearer request sent by the target-side SGW without obtaining the indication of the target-side mobility management element, or determine whether the end marker packet needs to be sent by itself according to the qos requirement of the user bearer context, for example, it is known that data required on a bearer is not damaged according to the qos requirement, and then the PGW may end the marker packet in the bearer path context.

And thirdly, sending by the target side SGW:

in this embodiment, after the source-side data is sent, the target-side SGW sends an end marker packet to the target-side access network element, where the end marker packet is used to instruct the target-side access network element to issue downlink data from the target-side core network to the user equipment.

referring to fig. 5, a fifth embodiment of a handover method according to the present invention includes:

501. the user equipment transmits uplink data and downlink data with the PGW through the source base station;

502. The source base station and the target base station negotiate to carry out switching;

503. The source base station transmits downlink data which is not sent to the user equipment to the target base station;

504. the target base station sends the received forwarding data to the user equipment;

505. the user equipment sends uplink data to the PGW through the target base station;

506. the target base station sends a path switching request to the MME;

507. The MME sends a bearer creation request to a target side SGW;

In this embodiment, the bearer creation request sent by the MME to the target side SGW includes indication information for indicating that the SGW has performed path switching and the source side data has been already delivered, or directly indicating that an end marker packet needs to be delivered, or even indicating a bearer list where the end marker packet needs to be delivered.

It should be noted that, in this embodiment, similarly to the first embodiment, the MME also needs to start a timer, and send a bearer creation request after the timer expires.

In this embodiment, the data of the source side is data delivered by the PGW through the SGW of the source side, and the data of the target side is data delivered by the PGW through the SGW of the target side, that is, after the SGW is switched, when the PGW delivers the data, there are two paths, one is a path where the SGW of the source side is located and is called a source side path, and the other is a path where the SGW of the target side is located and is called a target side path.

508. The target side SGW sends a bearer updating request to the PGW;

509. The PGW returns an update bearer response message to the SGW;

510. The target side SGW sends an end marking packet to the target side base station according to the instruction of the MME;

and the target side SGW forwards the end marker packet to the target side base station, so as to indicate that the target side base station can start to issue downlink data from the target side core network to the user equipment.

511. The target side SGW sends a bearer establishing response message to the MME;

512. The PGW sends downlink data to the user equipment through the target side base station;

513. the MME sends a path switching confirmation message to a target side base station;

514. The user equipment sends uplink data to the PGW through the target side base station;

515. the target side base station informs the source side base station of successful switching and requires the source side base station to release resources;

516. the MME sends a bearer deletion request to the source side SGW;

517. and the source side SGW feeds back a bearer deletion response message to the MME.

In the above embodiment, the indication information is carried in the bearer creation request sent by the MME to the target side SGW, and it can be understood that, in practical application, the target side SGW may determine whether the end marker packet needs to be issued according to the qos requirement of the user bearer context without obtaining the indication of the MME, for example, if it is known that data required on a certain bearer is not damaged according to the qos requirement, the target side SGW may issue the end marker packet.

It should be further noted that, the process of issuing the end marker packet by the target SGW may also adopt the following manner:

the MME sends a create bearer request to the source-side SGW without waiting for the timeout of the timer after step 506, where the create bearer request does not carry indication information, the target-side SGW sends an update bearer request to the PGW after receiving the create bearer request, and starts a timer after the PGW feeds back an update bearer response, and after the timer reaches a preset time, the target-side SGW confirms that the source-side data is sent, that is, sends an end marker packet, and releases the user plane resource.

B. 3GPP network (changing handover of core network mobility management network elements):

referring to fig. 6, a sixth embodiment of a handover method according to the present invention includes:

601. the source side access network element decides to initiate the switching;

602. the source side access network element sends a switching request message to the source side mobile management network element;

603. The source side mobile management network element sends a forwarding switching request to a target side mobile management network element;

604. Allocating resources by the target network;

605. The target side mobile management network element feeds back a forward switching response message to the source side mobile management network element;

606. a source side mobile management network element sends a bearer creation request to a source side SGW;

607. The source side SGW feeds back a bearer establishing response to the source side mobile management network element;

608. the source side mobile management network element sends a switching command to the source side access network element, and the switching command is used for indicating the source network to start switching;

609. the source side access network element sends a switching command to the user equipment for informing the UE of starting switching;

610. the source side access network element starts to forward data to a target network;

612. the target side access network element sends a switching notice to the target side mobility management network element;

613. The target side mobile management network element sends a forward switching completion message to inform the source side mobile management network element;

614. the source side mobile management network element returns a forward switching completion confirmation message to the target side mobile management network element;

615. the target side mobile management network element sends a load updating request message to a target side SGW to update user plane load information;

in this embodiment, the update bearer request sent by the target-side mobility management element to the target-side SGW includes indication information, which is used to indicate that the SGW has a path switch and the source-side data has been completely issued, or directly indicate that an end marker packet needs to be issued, or even indicate a bearer list where the end marker packet needs to be issued.

It should be noted that, in this embodiment, similarly to the first embodiment, the target-side mobility management network element also needs to start a timer, and sends an update bearer request after the timer expires.

616. The target side SGW sends a bearer updating request to the PGW;

617. The PGW feeds back an update bearing response to the target side SGW;

618. the target side SGW sends an end marker packet to a target side access network element, and is used for indicating that the target side access network element can start to issue downlink data from a target side core network to the user equipment;

619. and the target side SGW returns an update bearing response message to the target side mobile management network element.

In the above embodiment, the update bearer request sent by the target-side mobility management element to the target-side SGW carries indication information, and it can be understood that, in practical application, the target-side SGW may determine whether to issue the end marker packet according to the qos requirement of the user bearer context without obtaining an indication of the source-side mobility management element, for example, it is known that data required on a certain bearer is not damaged according to the qos requirement, and the target-side SGW may end the marker packet in the bearer path context.

after step 614, the MME sends an update bearer request to the source-side SGW without waiting for the timeout of the timer, where the update bearer request does not carry indication information, the target-side SGW sends the update bearer request to the PGW after receiving the create bearer request, and starts a timer after the PGW feeds back the update bearer response, and after the timer reaches the preset time, the target SGW confirms that the source-side data is sent, that is, sends the end marker packet, and releases the user plane resource.

The above describes how to ensure a data-lossless handover when a serving gateway changes, as a user equipment moves from a source network to a target network, and, in particular,

when the source network is GERAN, the source side access network element is a base station subsystem, and the source side mobile management network element is a Serving GPRS Support Node (SGSN);

when the source network is UTRAN, the source side access network element is a radio network controller, and the source side mobile management network element is SGSN;

when the source network is EUTRAN, the source side access network element is an evolution base station, and the source side mobile management network element is MME;

when the target network is GERAN, the target side access network element is a base station subsystem, and the target side mobile management network element is SGSN;

when the target network is UTRAN, the target side access network element is a radio network controller, and the target side mobile management network element is SGSN;

and when the target network is EUTRAN, the target side access network element is an evolution base station, and the target side mobile management network element is MME.

In the foregoing embodiment, after the source-side SGW is handed over to the target-side SGW, the network-side core network device sends an end tag packet to the target-side access network element, where the end tag packet is used to instruct the target-side access network element to send downlink data from the target-side core network to the user equipment, so that even if the serving gateway changes, the target-side access network element can still obtain the end tag packet from the network-side core network device for lossless data handover, and thus, lossless data handover can be implemented when the SGW changes.

Referring to fig. 7, a communication system in an embodiment of the present invention is described below, where the communication system in the embodiment of the present invention includes:

the network side core network device 702 is configured to send an end marker packet to the target side access network element 701 after the access network is switched and the source side SGW is switched to the target side SGW;

and the target side access network element 701 is configured to receive the end marker packet sent by the network side core network device 702, and after receiving the end marker packet, issue downlink data from the target side core network to the user equipment.

The network side core network device 702 includes:

a source-side SGW, or a target-side SGW, or a PGW.

For ease of understanding, the following description of the present communication system embodiment is given by taking the first embodiment of the foregoing method embodiments as an example:

the source side access network element and the target side access network element carry out interaction to determine that switching is needed, and then the source side access network element and the target side access network element carry out switching preparation and forward data to complete switching;

the target side access network element sends a path switching request to an MME in the network side core equipment, the MME completes the processes of creating and updating the load bearing between the path switching request and the target side SGW and PGW, starts a timer after receiving a response fed back by the target side SGW, and sends a path switching confirmation message to the target side access network element;

when a timer started by the MME overflows, namely the source side data is considered to be completely issued, the MME sends a bearer deletion request to the source side SGW, wherein the bearer deletion request contains indication information used for indicating that the SGW path is changed and requesting the source side SGW to issue an end marker packet;

the source side SGW feeds back a bearer deletion response to the MME and sends an end marking packet to the source side access network element, the source side access network element forwards the end marking packet to a target side access network element, and the source side SGW releases user plane resources of the source side SGW after sending the end marking packet.

Referring to fig. 8, an SGW embodiment in the embodiment of the present invention is described below, where the service gateway embodiment in the embodiment of the present invention includes:

a triggering unit 801, configured to trigger the sending unit 802 when preset sending conditions are met after the access network is switched and the source-side SGW is switched to the target-side SGW;

a sending unit 802, configured to send the end marker packet to the target side access network element according to the trigger of the triggering unit 801, where the end marker packet is used to instruct the target side access network element to issue downlink data from the target side core network to the user equipment according to the instruction of the end marker packet.

It should be noted that the trigger unit 801 may specifically include at least one of the following sub-units:

an indication receiving subunit 8011, configured to receive indication information sent by the mobility management element, and confirm that a preset sending condition is met according to the indication information, where the indication information is used to indicate that the end marker packet is sent;

or

A bearer processing request receiving subunit 8012, configured to receive a bearer processing request sent by the mobility management element, and determine, according to the bearer processing request, that a preset sending condition is met, where the bearer processing request includes a bearer deletion request, a bearer creation request, or a bearer update request, where the bearer processing request is sent by the mobility management element after determining that sending of downlink data of the source-side core network is completed;

the self-determination subunit 8013 is configured to start a timer after receiving a request for deleting a bearer, or a request for creating a bearer, or a request for updating a bearer, and determine that a preset sending condition is met after the timer expires.

It should be noted that the bearer processing request received by the bearer processing request receiving unit 8012 may be a request for deleting a bearer, a request for creating a bearer, or a request for updating a bearer.

The service gateway in this embodiment may further include:

a determining unit 803, configured to further determine, according to a preset quality of service parameter, whether an end marker packet needs to be issued when the triggering unit triggers the sending unit, and if so, instruct the sending unit to send the end marker packet;

a resource releasing unit 804, configured to release the user plane resource of the user plane after the sending unit 802 sends the end marker packet to the target side access network element.

When the SGW in this embodiment is used as the source-side SGW, the bearer processing request receiving unit 8012 in the triggering unit 801 receives a bearer deletion request from the MME;

and the sending unit 802 sends the end marker packet to the target side access network element according to the delete bearer request;

and the source-side SGW needs to include a resource release unit 804;

when the SGW in this embodiment is the target SGW, the bearer processing request receiving unit 8012 in the triggering unit 801 receives an update bearer request from the MME;

the sending unit 802 sends the end marker packet to the target side access network element according to the update bearer request.

Referring to fig. 9, an embodiment of a packet data network gateway according to the present invention includes:

an end-marker packet triggering unit 901, configured to trigger an end-marker packet sending unit 902 when preset sending conditions are met after an access network handover occurs and a source-side serving gateway SGW is handed over to a target-side SGW;

an end marker packet sending unit 902, configured to send an end marker packet to a source side access network element according to the trigger of the end marker packet triggering unit 901, where the end marker packet is used to instruct the target side access network element to issue downlink data from a target side core network to a user equipment according to the instruction of the end marker packet.

In this embodiment, the end marker packet triggering unit 901 may include at least one of the following sub-units:

a sending instruction receiving subunit 9011, configured to receive instruction information sent by a target side service gateway SGW, and confirm that a preset sending condition is met according to the instruction information, where the instruction information is used to instruct to send an end marker packet;

or

An update bearer request receiving unit 9012, configured to receive an update bearer request sent by the target-side SGW, and confirm that a preset sending condition is met according to the update bearer request.

It should be noted that the update bearer request sent by the target SGW may include indication information;

the packet data network gateway in this embodiment may further include:

a sending and determining unit 903, configured to further determine, according to a preset quality of service parameter, whether an end marker packet needs to be sent when the end marker packet triggering unit triggers the end marker packet sending unit, and if so, instruct the end marker packet sending unit to send the end marker packet.

It will be understood by those skilled in the art that all or part of the steps in the method for implementing the above embodiments may be implemented by hardware that is related to instructions of a program, and the program may be stored in a computer-readable storage medium, and when executed, the program includes the following steps:

The storage medium mentioned above may be a read-only memory, a magnetic or optical disk, etc.

While the switching method, the communication system and the related devices provided by the present invention have been described in detail, those skilled in the art will appreciate that the embodiments and applications of the present invention are not limited thereto.

Claims

1. A method of handover, comprising:

and when the access network is switched and the source side SGW is switched to the target side SGW, sending an end marking packet to a target side access network element so as to facilitate the target side access network element to issue downlink data from the target side core network to the user equipment according to the indication of the end marking packet.

2. The method of claim 1, wherein the sending the end-marker packet to the target-side access network element specifically comprises:

and the source side SGW sends an end marking packet to the target side access network element through the source side access network element.

3. The method of claim 2, wherein the sending, by the source-side SGW, the end-marker packet to the target-side access network element via the source-side access network element specifically comprises:

after receiving indication information of a mobility management network element or a bearer deletion request sent by the mobility management network element, the source-side SGW sends an end marker packet to a target-side access network element, where the indication information or the bearer deletion request is sent by the mobility management network element after determining that downlink data of a source-side core network is completely sent, and the indication information is used for indicating the source-side SGW to issue the end marker packet;

or,

and the source side SGW receives the bearer deletion request sent by the mobile management network element, and after determining that the sending of the downlink data of the source side core network is finished, the source side SGW sends an end marking packet to a target side access network element.

4. The method of claim 3, wherein the sending, by the source-side SGW, the end marker packet to the target-side access network element after receiving the indication information of the mobility management network element specifically comprises:

the source-side SGW receives a bearer deletion request sent by the mobile management network element, wherein the bearer deletion request comprises indication information;

a source side SGW sends an end marking packet to a source side access network element and feeds back a bearer deletion response to a mobile management network element, wherein the end marking packet is forwarded to a target side access network element by the source side access network element;

and the source side SGW releases the self user plane resources.

5. The method of claim 3, wherein after receiving the bearer deletion request sent by the mobility management element, the source-side SGW further sends an end marker packet to the target-side access element, and before the method further includes:

and judging whether an end marking packet needs to be issued or not according to the service quality requirement of the user bearing context, and if so, executing the step of sending the end marking packet to the target side access network element.

6. The method according to claim 3, wherein the determining, by the mobility management element, that the sending of the downlink data of the source-side core network is completed specifically includes:

when the access network switching does not cause the change of a core network mobility management network element, the mobility management network element starts a timer after receiving a bearer creation response sent by a target side SGW, and when the timer is overtime, the mobility management network element determines that the sending of downlink data of the source side core network is finished;

or

When the access network switching causes the change of the core network mobility management element, the source side mobility management element starts a timer after receiving a forwarding switching completion message sent by the target side mobility management element, and when the timer is overtime, the source side mobility management element determines that the sending of the downlink data of the source side core network is completed.

7. The method according to claim 3, wherein the determining, by the source-side SGW, that the sending of the downlink data of the source-side core network is completed specifically includes:

and the source side SGW starts a timer after receiving the bearer deletion request, and determines that the sending of the downlink data of the source side core network is finished after the timer is overtime.

8. The method of claim 1, wherein the sending the end-marker packet to the target-side access network element specifically comprises:

and the PGW sends an end marking packet to the target side access network element through the source side access network element.

9. The method of claim 8, wherein the sending, by the PGW, the end-marker packet to the target side access network element through the source side access network element specifically comprises:

after receiving indication information sent by a mobile management network element through a target side SGW, the PGW sends an end mark packet to a target side access network element, wherein the indication information is used for indicating the PGW to issue the end mark packet;

or, after receiving the bearer update request sent by the target side SGW, the PGW sends an end marker packet to the target side access network element.

10. The method of claim 1, wherein the sending the end-marker packet to the target-side access network element specifically comprises:

and the target side SGW sends an end marking packet to the target side access network element.

11. The method as claimed in claim 10, wherein the sending, by the target-side SGW, the end-marker packet to the target-side access network element specifically includes:

after receiving indication information of a mobility management network element, or after receiving a bearer creation request or a bearer update request sent by the mobility management network element, the target side SGW sends an end marker packet to a target side access network element, where the indication information, the bearer creation request or the bearer update request are sent after the mobility management network element determines that downlink data of a source side core network is sent, and the indication information is used for indicating the source side SGW to issue the end marker packet;

or,

and the target side SGW receives a bearer creating request or a bearer updating request sent by the mobile management network element, and sends an end marking packet to the target side access network element after determining that the downlink data of the source side core network is sent completely.

12. The method of claim 11, wherein the sending, by the SGW on the target side, the end marker packet to the target side access network element after receiving the indication information of the mobility management network element specifically includes:

the target side SGW receives a bearer creating request or a bearer updating request sent by the mobile management network element, wherein the bearer creating request or the bearer updating request comprises indication information;

13. The method of claim 11, wherein after receiving the bearer creation request or the bearer update request sent by the mobility management element, the target-side SGW further sends an end tag packet to the target-side access element, and before the method further includes:

and judging whether an end marking packet needs to be issued or not according to the service quality requirement of the user bearing context, if so, the target side SGW sends the end marking packet to a target side access network element.

14. The method of claim 11, wherein the determining, by the mobility management element, that the sending of the downlink data of the target-side core network is completed specifically includes:

or

When the access network switching causes the change of the core network mobility management element, the target side mobility management element starts a timer after sending a forward switching completion message to the source side mobility management element, and when the timer is overtime, the target side mobility management element determines that the sending of the downlink data of the source side core network is completed.

15. The method according to claim 11, wherein the determining, by the target-side SGW, that the sending of the downlink data of the source-side core network is completed specifically includes:

and after receiving the bearer creation request or the bearer update request, the target side SGW starts a timer, and determines that the sending of the downlink data of the source side core network is finished after the timer is overtime.

16. The method of any one of claims 3, 4, 5, 6, 7, 9, 11, 12, 13, 14, or 15,

the mobile management network element is a mobile management entity MME or a serving general packet radio service node SGSN.

17. A communication system, comprising:

the network side core network equipment is used for sending an end marking packet to a target side access network element after the access network switching occurs and the source side service gateway SGW is switched to the target side SGW;

and the target side access network element is used for receiving the end mark packet sent by the network side core network equipment and sending downlink data from the target side core network to the user equipment after receiving the end mark packet.

18. The communication system according to claim 17, wherein the network-side core network device comprises:

a source side SGW, or a target side SGW, or a packet data network gateway PGW.

19. A serving gateway, comprising:

the triggering unit is used for triggering the sending unit when preset sending conditions are met after the access network switching occurs and the source side SGW is switched to the target side SGW;

and the sending unit is used for sending an end mark packet to the target side access network element according to the trigger of the trigger unit, wherein the end mark packet is used for indicating the target side access network element to send downlink data from the target side core network to the user equipment according to the indication of the end mark packet.

20. The serving gateway of claim 19, wherein the triggering unit comprises at least one of the following sub-units:

an indication receiving subunit, configured to receive indication information sent by a mobility management network element, and confirm that a preset sending condition is met according to the indication information, where the indication information is used to indicate that a sending end marker packet is sent;

or

A bearer processing request receiving subunit, configured to receive a bearer processing request sent by a mobility management element, and determine, according to the bearer processing request, that a preset sending condition is met, where the bearer processing request includes a bearer deletion request, a bearer creation request, or a bearer update request, and the bearer processing request is sent by the mobility management element after determining that sending of downlink data of a source-side core network is completed;

or

And the self-determination subunit is used for starting a timer after receiving the request for deleting the bearer, or the request for creating the bearer, or the request for updating the bearer, and determining that the preset sending condition is met after the timer is overtime.

21. The serving gateway of claim 20, wherein the serving gateway further comprises:

and the judging unit is used for further judging whether an end mark packet needs to be issued according to preset service quality parameters when the triggering unit triggers the sending unit, and if so, indicating the sending unit to send the end mark packet.

22. The serving gateway according to any of claims 19 to 21, wherein the serving gateway comprises: a source side serving gateway SGW or a target side serving gateway SGW.

23. The serving gateway of claim 22, wherein when the serving gateway is a source-side SGW, the serving gateway further comprises:

and the resource releasing unit is used for releasing the user plane resource of the user plane after the sending unit sends the end marking packet to the target side access network element.

24. A packet data network gateway, comprising:

an end marker packet triggering unit, configured to trigger an end marker packet sending unit when preset sending conditions are met after an access network handover occurs and a source side serving gateway SGW is handed over to a target side SGW;

and an end marker packet sending unit, configured to send an end marker packet to a source side access network element according to the trigger of the end marker packet triggering unit, where the end marker packet is used to instruct the target side access network element to issue downlink data from a target side core network to a user equipment according to the instruction of the end marker packet.

25. A packet data network gateway according to claim 24, wherein the end-marker packet triggering unit comprises at least one of the following sub-units:

a sending indication receiving subunit, configured to receive indication information sent by a target side service gateway SGW, and confirm that a preset sending condition is met according to the indication information, where the indication information is used to indicate a sending end marker packet;

or

And the update bearer request receiving subunit is configured to receive an update bearer request sent by the target side SGW, and confirm that a preset sending condition is met according to the update bearer request.

26. A packet data network gateway according to claim 24 or 25,

and the sending judgment unit is used for further judging whether the end mark packet needs to be sent according to preset service quality parameters when the end mark packet triggering unit triggers the end mark packet sending unit, and if so, indicating the end mark packet sending unit to send the end mark packet.