CN1859285A - Method for equalizing load between gateways of WiMAX access service network - Google Patents

Abstract

The present invention relates to WiMAX access service network technology, in particular to a method for load balancing between gateways in the WiMAX access service network. After receiving the access request message, the service gateway performs the following steps: the service gateway obtains the resource status of the relevant gateway, selects the load The smaller gateway acts as the target gateway. If the selected gateway is the serving gateway itself, the serving gateway processes the access request, otherwise, forwards the access request message to the target gateway. The present invention adjusts the load of each relevant gateway in time by allowing the resource usage states of the relevant gateways in the WiMAX access service network to communicate with each other, so as to balance the load well, ensure the normal operation of the system, and improve the system efficiency.

Description

Method of load balancing between gateways in WiMAX access service network

[technical field]

The invention relates to WiMAX access service network technology, in particular to a method for load balancing between gateways in the WiMAX access service network.

[Background technique]

With the vigorous development of Internet services and the wide application of wireless networks, the WiMAX system has received a lot of applications and attention due to its good wireless access characteristics. How the WiMAX system is applied to mobile users, and how to better provide the forwarding or routing function of packet services between the network and mobile users has become a new focus of research in the industry.

The WiMAX network architecture system is shown in Figure 1. Among them, ASN (Access Service Network) is defined as a set of network functions that provide wireless access services for WiMAX terminals, and ASN includes base station (BS) and access service network gateway (ASN-GW) network elements. CSN (Connection Service Network) is defined as providing IP connection services for WiMAX terminals. MSS (Mobile Subscriber Station) is mobile user equipment, and SS (Subscriber Station) is user equipment, which is used by users to access the WiMAX network. A CSN is a network device belonging to an NSP (Network Service Provider). One ASN can connect to multiple CSNs. There can be many-to-many connections between BS and ASN-GW. As shown in Figure 1, ASN-GW1 can connect to BS1 and BS2 at the same time, and BS1 can connect to ASN-GW1 and ASN-GW2 at the same time.

The BS used for MSS/SS access is called the serving base station (Serving BS). For an MSS/SS accessed by a serving BS, the ASN-GW that has an R6 interface with the BS is called Serving ASN-GW. For example, ASN-GW1 in Figure 1 uses BS1 or BS2 The service gateway of the connected MSS/SS. The ASN-GW that provides the R3 interface between the R3 of the HA from the ASN to the CSN is called an anchor ASN-GW (AnchorASN-GW). The anchor ASN-GW in FIG. 1 is a logical entity, which may exist in the same or different physical entities as the logical entities such as ASN-GW1 and ASN-GW2 in FIG. 1 . When the anchor ASN-GW and the serving ASN-GW exist in the same physical entity, the interface between the two belongs to the internal interface of the device, and the standard R4 interface does not have to be used.

From the perspective of the data plane, the packet service datagram of the downlink MSS/SS is transmitted from the HA (home agent) of the CSN to the ASN through the R3 interface between the HA and the anchor ASN-GW in the ASN. After the downlink MSS/SS packet service datagram enters the ASN, it is transmitted to the serving ASN-GW of the MSS/SS through the R4 interface inside the ASN, and then the serving ASN-GW passes through the R6 interface between the ASN-GW and the BS inside the ASN The R1 interface between the BS and the MSS/SS sends the data of the MSS/SS to the MSS/SS. Uplink data is transferred from MSS/SS to CSN along the opposite path and reaches the opposite end user. As mentioned above, in the interface inside the ASN, there is a corresponding uplink and downlink data path (Data Path) for each service flow of each MSS/SS, which will be based on each service flow when each service flow is established. The QoS requirements and the way the data path is used are established. When the service ends, that is, when the service flow is terminated, the corresponding data path needs to be released.

When the MSS/SS may move from the coverage area of one BS to the coverage area of another BS during the mobile process, and the serving BS and the target BS belong to the same ASN GW, the handover that occurs is called R6 interface mobility handover. When the MSS/SS may move from the coverage area of one BS to the coverage area of another BS while the serving BS and the target BS belong to different ASN GWs, the handover that occurs is called R4 interface mobility handover. As shown in Figure 2, before the R4 interface handover occurs, the MSS/SS uses BS2 to access the network, and connects to the CSN through the bold link. As shown in Figure 3, after the R4 interface switchover occurs, the MSS/SS uses BS3 to access the network, and the MSS/SS connects to the CSN through the bold link. It can be seen that the MSS/SS performs data transmission through the R4 interface data path between the new serving ASN-GW and the anchor ASN-GW. Figure 4 shows the switching process of the R4 interface.

Generally, there are multiple ASN-GWs in one ASN, and how to perform load balancing among the ASN-GWs becomes a problem to be solved. The patent number is 200510064665.X, and the application name is "A Network Optimization Method Based on Distributed Wireless Access Network". Delay information with a certain GW path will also be measured. The disadvantages of this approach are: ① BS is at the edge of the network and cannot fully understand the resource status of each ASN-GW in the entire network, so the effect of load balancing will definitely be affected; ② increases the processing burden of BS; ③ in the network The number of BSs is much larger than that of ASN-GW, and the resource broadcast issued by ASN-GW will occupy more system resources; ④There is no intercommunication resource status between ASN-GW, so, in the R4 interface handover, when serving ASN-GW needs to select When targeting the ASN-GW, since the serving ASN-GW does not know the resource status of multiple ASN-GWs connected to the target BS, it will not be able to select the target ASN-GW according to the resource status to achieve the purpose of load balancing.

[Content of the invention]

The purpose of the present invention is to provide a method for balancing load among gateways in a WiMAX access service network.

In the method for load balancing between gateways in the WiMAX access service network, the service gateway performs the following steps after receiving the access request message:

101. The serving gateway obtains the resource status of related gateways, and selects a gateway with a smaller load as the target gateway. If the selected gateway is the serving gateway itself, the serving gateway processes the access request, otherwise, the access request packet forwarded to the destination gateway.

The method for load balancing between gateways in the WiMAX access service network further includes a step before step 101: the serving gateway judges whether the resource status of the relevant gateway has been obtained, and if not, requests to obtain the resource status of the relevant gateway.

A method for load balancing between gateways in a WiMAX access service network, the method for obtaining the state of related gateway resources includes steps:

301. The serving gateway sends a resource status request message to the relevant gateway, where the resource status request message includes the resource status of the serving gateway itself;

302. The relevant gateway returns a resource status response message to the service gateway, carrying its own resource status.

In the method for load balancing between gateways in a WiMAX access service network, the gateways regularly broadcast and send resource status broadcast messages, and the service gateway obtains the resource status of related gateways through the resource status broadcast messages.

The method for load balancing between gateways in the WiMAX access service network further includes a step before performing step 101: the service gateway judges whether its own resource occupancy has reached a threshold, and if so, executes step 101, otherwise processes the access request.

The resource status includes at least one of the following contents: user capacity resource, bandwidth resource, path transmission delay and bit error rate, processor resource, memory resource, ingress port resource and egress port resource.

The access includes network initial access and handover access.

The relevant gateway is a gateway connected to the serving gateway, or the base station managed by it is also managed by the serving gateway, or the base station managed by it has a neighboring cell with the serving base station.

As an improvement of the present invention, when the service gateway forwards the access request to the target gateway, a forwarding times parameter is added in the message, and each time the message is forwarded, the value of the forwarding times is increased by one, and when the forwarding When the number of times reaches a preset value, the current serving gateway is set as the final access gateway, and the access request is processed.

The present invention also provides a method for load balancing between gateways in a WiMAX access service network. Gateways regularly broadcast and send resource status broadcast messages to obtain the resource status of related gateways; The base station sends a handover request, requesting the serving base station to switch some subscriber stations to the base station connected to the relevant gateway.

In the above method, the handover request message includes one or a combination of the following contents: a list of recommended target gateways, and a percentage of handover mobile subscriber stations.

The above method further includes: the mobile user station sends a handover instruction to the serving base station, and the handover instruction includes the information of the selected target gateway.

The present invention adjusts the load of each related gateway in time by allowing the related gateways in the WiMAX access service network to communicate with each other about the resource usage status, so as to balance the load well, ensure the normal operation of the system, and improve the system efficiency.

[Description of drawings]

Figure 1 is a system diagram of the WiMAX network architecture.

Figure 2 is a data link diagram used by the MSS/SS before the R4 interface is switched.

Fig. 3 is a data link diagram used by the MSS/SS after the R4 interface is switched.

FIG. 4 is a schematic diagram of the switching flow of the R4 interface.

Fig. 5 is a schematic flowchart of Embodiment 1 of the present invention.

Fig. 6 is a schematic flow chart of Embodiment 2 of the present invention.

Fig. 7 is a schematic flow chart of Embodiment 3 of the present invention.

[Detailed ways]

The present invention will be further elaborated below according to the drawings and specific embodiments.

Embodiment one:

Each gateway (ASN-GW) in the access service network (ASN) periodically sends a resource status request message to each relevant ASN-GW, and broadcasts its resource and load conditions. The message carries one or any combination of the following information: User capacity resource status, bandwidth resource status, path transmission delay and bit error rate, processor resource status, memory resource status, ingress port resource status and ingress port resource status, etc. Specifically, it may involve: ASN-GW user capacity resource usage ratio, ASN-GW total user capacity, ASN-GW connected user volume, ASN-GW remaining user capacity, ASN-GW use a certain QoS level The number of users connected, the bandwidth resource usage ratio of ASN-GW, the total bandwidth capacity of ASN-GW, the remaining bandwidth of ASN-GW, the bandwidth used by ASN-GW, the path transmission delay between ASN-GW and BS, The path transmission bit error rate between ASN-GW and BS, ASN-GW processor resource occupancy rate, ASN-GW processor total resources, ASN-GW processor used resources, ASN-GW processor remaining resources, ASN-GW GW storage resource occupancy rate, ASN-GW total storage resource, ASN-GW storage used resource, ASN-GW storage remaining resource, ASN-GW ingress port resource occupancy rate, ASN-GW ingress port total traffic, ASN-GW ingress port Used traffic, ASN-GW incoming port remaining traffic, ASN-GW outgoing port resource occupancy rate, ASN-GW outgoing port total traffic, ASN-GW outgoing port used traffic, and ASN-GW outgoing port remaining traffic.

As shown in Figure 5, it is a schematic flow diagram of a mobile subscriber station (MSS) requesting initial network access, which mainly includes the following steps:

S11, the serving ASN-GW receives an MSS access request from the serving BS or from other ASN-GWs.

S12, the serving ASN-GW judges whether its own resource occupancy rate has reached the threshold, if not, execute step S17; if it has reached, execute step S13.

S13, the serving ASN-GW judges whether the serving BS has a connection relationship with other ASN-GWs, if yes, and the ASN-GW has obtained the resource status of these adjacent ASN-GWs through broadcasting, then execute step S14; if If not, execute step S17. Since each gateway in this embodiment uses periodic broadcasts to obtain the status of related gateway resources, it is not necessary to obtain related gateway resources when receiving an access request, as long as the result obtained from the latest broadcast is used.

S14, the serving ASN-GW judges whether its own resource occupancy rate is the lowest, if not, execute step S15; if yes, execute step S17.

S15. Select the ASN-GW with the lightest load among the relevant ASN-GWs as the target gateway, forward the access request of the MSS to the selected ASN-GW, and increase the forwarding hop count in the message by 1.

S16, the selected target ASN-GW serves as the service gateway to receive the access request of the MSS, and judges whether the forwarding hop count reaches the preset value, and if so, execute step S17; if not, execute step S12.

S17, processing the access request of the MSS as the final service gateway, and completing subsequent access processing.

As an improvement of the present invention, in order to prevent the ASN-GW from forwarding the above access request to each other without restriction, the above forwarding hop count is added to the forwarded access request message. Each time the access request is forwarded, the forwarding hop count is increased by 1, and when the forwarding hop count reaches a preset value, it is no longer forwarded, and the last ASN-GW accesses the MSS. The preset value can be used as an operating parameter to be uniformly configured throughout the network.

Embodiment two:

As shown in Figure 6, it is a schematic flow diagram of the gateway receiving an MSS handover request from another serving ASN-GW, which mainly includes the following steps:

S21, the ASN-GW receives an MSS handover request from the serving BS or from other ASN-GWs, and the handover request includes target BS information.

S22, the ASN-GW judges whether the resource status of the relevant gateway has been obtained, if it has been obtained, execute step S23; if not, request to obtain the resource status of the relevant gateway, and then execute step S23. Wherein, the relevant gateway refers to the ASN-GW that has a connection relationship with the target BS. Since the target BS information is carried in the handover request from the serving BS or from other serving ASN-GWs, the information of the ASN-GW connected to the target BS can be obtained through a certain method. The definition of the resource state is the same as that in the first embodiment.

S23, the ASN-GW judges whether its own resource occupancy rate is the lowest, if not, execute step S24; if yes, execute step S26.

S24. Select the ASN-GW with the lightest load among the relevant ASN-GWs as the target gateway, forward the handover request from the MSS to the selected ASN-GW, and increase the forwarding hop count in the message by 1.

S25, the selected target ASN-GW receives the handover request from the MSS, and judges whether the number of forwarding hops reaches the preset value, and if so, execute step S26; if not, execute step S22.

S26, processing the handover request of the MSS as the final service gateway, and completing subsequent access processing.

In the above step S22, the method for requesting to obtain the status of the relevant gateway resources includes the steps:

S221. The ASN-GW sends a resource status request message to the relevant gateway, and the resource status request message includes its own resource status.

S222. The relevant gateway returns a resource status response message to the above-mentioned ASN-GW, and the returned message includes the resource status of the relevant gateway.

It can be seen that, compared with the first embodiment, this embodiment can better balance the load among the gateways. At the same time, the constant load balancing between gateways will also increase the burden on the system. Therefore also can be the same as Embodiment 1, add steps after step S21:

S211, the ASN-GW judges whether its own resource occupancy rate has reached the threshold, if it has reached, execute step S22; if not, execute step S26.

In this way, only after the load of one ASN-GW reaches a threshold, the subsequent load (MSS/SS) will be distributed to other ASN-GWs.

In this embodiment, step S22 can also be removed as in the embodiment, and periodic broadcasting is used to obtain related gateway resources and load status.

Embodiment three:

In this embodiment, each gateway (ASN-GW) in the access service network (ASN) periodically sends a resource status broadcast message to each related ASN-GW, and broadcasts its resource and load conditions, so as to obtain the resource status of the related gateway. The relevant gateway refers to a gateway that is connected to the source ASN-GW, and the BS managed by it is also managed by the source ASN-GW, or the BS managed by it and the BS managed by the source ASN-GW have adjacent cells. The ASN-GW may send the resource status request message to all relevant ASN-GWs satisfying the above definition, or may only select a subset thereof to send. The definition of the resource state is the same as that in the first embodiment.

The serving ASN-GW wants to reduce its own resource occupation ratio due to operation and maintenance, or finds that its own resources have reached the threshold, and the load in the adjacent ASN-GW is still relatively light, so the ASN-GW initiates a handover process to the serving ASN-GW. The BS sends a handover request, requesting the serving BS to hand over some MSSs to other BSs connected to the ASN-GW. As shown in Figure 7, it is a schematic diagram of the process of the service gateway actively initiating a handover, which mainly includes the following steps:

S31, the serving ASN-GW judges whether its own resource occupancy rate has reached the threshold, if it has reached the threshold, execute step S32, and if not, continue to judge.

S32, the serving ASN-GW decides to transfer part of the load to the relevant ASN-GW, and selects the relevant ASN-GW to form a recommended target gateway list.

S33, the serving ASN-GW actively sends a handover request to the serving BS, requesting the serving BS to handover some MSSs to the relevant ASN-GW, and the handover request includes a list of recommended target ASN-GWs and a percentage of mobile subscriber stations to be handed over.

S34. The serving BS receives the handover request, determines the MSS that needs to be handed over, and sends the handover request to it;

S35, the MSS initiates a handover instruction to the serving BS.

S36. After receiving the handover instruction, the serving BS selects one from the recommended target ASN-GW list as the target ASN-GW, and adds the information of the target gateway to the handover instruction and sends it to the serving ASN-GW. .

S37. After receiving the handover instruction sent by the serving BS, the serving ASN-GW sends the handover instruction to the selected target ASN-GW.

S38, start the switching process.

To sum up, the method of the present invention can adjust the loads of relevant gateways in time, balance the loads well, ensure the normal operation of the system, and improve the system efficiency.

Claims (12)

1. The method for load balancing between gateways in the WiMAX access service network, characterized in that the service gateway performs the following steps after receiving the access request message: 101. The serving gateway obtains the resource status of related gateways, and selects a gateway with a smaller load as the target gateway. If the selected gateway is the serving gateway itself, the serving gateway processes the access request, otherwise, the access request packet forwarded to the destination gateway. 2. The method according to claim 1, further comprising a step before performing step 101: the service gateway judges whether the resource status of the relevant gateway has been obtained, and if not, requests to obtain the resource status of the relevant gateway. 3. The method according to claim 1 or 2, characterized in that the method for obtaining the status of related gateway resources comprises the steps of: 301. The serving gateway sends a resource status request message to the relevant gateway, where the resource status request message includes the resource status of the serving gateway itself; 302. The relevant gateway returns a resource status response message to the service gateway, carrying its own resource status. 4. The method according to claim 3, characterized in that: the resource status broadcast message is regularly broadcast between the gateways, and the service gateway obtains the resource status of the relevant gateway through the resource status broadcast message. 5. The method according to claim 1, characterized in that before performing step 101, it further comprises a step: the service gateway judges whether its own resource occupancy rate has reached the threshold, if it has reached, then perform step 101, otherwise process the access request . 6. The method according to claim 1, 2 or 5, wherein the resource status includes at least one of the following contents: user capacity resource, bandwidth resource, path transmission delay and bit error rate, processor resource, memory resource , ingress port resource and egress port resource. 7. The method according to claim 1, wherein the access includes network initial access and handover access. 8. The method according to claim 1 or 2, characterized in that: the relevant gateway is a gateway connected to the serving gateway, or the base station managed by it is also managed by the serving gateway, or the base station managed by it is the same as the serving base station have adjacent cells. 9. The method according to claim 1, further comprising: when the service gateway forwards the access request to the target gateway, adding a forwarding times parameter in the message, and each time the message is forwarded, the forwarding The value of the number of times is increased by one, and when the number of times of forwarding reaches a preset value, the current serving gateway is set as the final access gateway to process the access request. 10. A method for load balancing between gateways in a WiMAX access service network, characterized in that: regularly broadcast resource status broadcast messages between gateways to obtain the resource status of relevant gateways; Sending a handover request requesting the serving base station to hand over some subscriber stations to the base station connected to the relevant gateway. 11. The method according to claim 10, characterized in that said handover request message includes at least one of the following contents: a list of recommended target gateways, and a percentage of handover mobile subscriber stations. 12. The method according to claim 11, further comprising: after receiving the handover instruction from the mobile subscriber station, the serving base station selects a target gateway in the list of recommended target gateways, and transfers the information of the target gateway to Added to the handover instruction sent to the service gateway.

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