CN104066207B - A kind of 802.11 wireless access networks based on virtualization technology - Google Patents

Abstract

The invention discloses an 802.11 wireless access network based on virtualization technology, which includes a virtual access point and more than two physical access points, and the virtual access point includes a virtualized wireless network card capable of generating 802.11 data frames, The first tunnel and virtual switch for encapsulating 802.11 data frames; the virtual wireless network card is connected to the virtual switch through the first tunnel; each physical access point includes a wired network card, a wireless network card and a second tunnel for encapsulating 802.11 data frames, and the wired network card The second tunnel is connected to the wireless network card, and the virtual switch is respectively connected to the wired network cards in each physical access point in a wired manner. The present invention can realize seamless switching between physical wireless access points, effectively solves the problem of wireless local area network signal coverage in a small and medium range, and simplifies network topology and unified management and monitoring planning by using an open virtual switching standard switch and a software-defined network controller Configuration can provide the basis for network-wide optimization.

Description

An 802.11 Wireless Access Network Based on Virtualization Technology

technical field

The invention relates to network virtualization technology and a wireless access network, and belongs to the technical field of mobile communication.

Background technique

With the maturity and rapid development of wireless communication technology, the use of mobile devices such as smartphones and tablet computers has exploded. People are increasingly relying on mobile Internet devices, and the mobility requirements of wireless local area networks (WLANs) are becoming stronger and stronger. As WLAN applications become more and more widespread, more and more wireless access points are deployed to meet people's needs. Traditional wireless access points are usually independent and uncontrolled. This design routine is gradually being replaced, and wireless access points are becoming more and more multifunctional and diversified. Since the coverage area of a single wireless access point is limited, a wireless access network with multiple access points needs to be used in many cases.

The traditional multi-access point wireless access network has the structure of the same extended service set to realize the roaming of multiple wireless access points. In this way, in the wireless roaming network, the client configuration is exactly the same as that in the access point network, and the user There is no need to manually switch during the process. However, this method cannot achieve seamless connection, the switching process takes a lot of time, the user experience is poor, configuration modification is inconvenient, centralized management and deployment cannot be performed, and it cannot well meet the needs of indoor wireless networks.

At this stage, the enterprise-level wireless access network usually adopts the "wireless switch + thin wireless access point" solution. The purpose of this solution is to solve the shortcomings of the original wireless access point products that cannot be centrally managed and deployed security policies. In this solution architecture, it consists of three parts, which are thin wireless access point, wireless controller, and wireless network management platform. This mode is safe and effective, but its disadvantages are high cost and high complexity, professional network management is required to configure the product, and there are technical barriers in the products of various manufacturers, and the products must be used together, so it is not suitable for flexible network layouts such as smart homes. .

Currently, virtualization technology has become an important means to improve cluster performance, improve utilization efficiency, reduce total cost of ownership, and enhance system flexibility. Network virtualization is a way to separate network traffic from physical network elements using software-based abstractions. Among them, the "multiple virtual one" technology is to virtualize multiple independent physical units into a logical unit, so that multiple units cooperate with each other to process the same task. Its main purpose is to expand resources and increase the capacity of network nodes. At the same time, it also simplifies the network topology, facilitates management, and enhances network reliability.

The Open Virtual Switching standard switch (Open vSwitch) has received widespread attention in the industry, and its goal is to realize a multi-layer virtual switch with product-level quality. Through programmable expansion, automatic configuration, management and maintenance of large-scale networks can be realized. It supports existing standard management interfaces and protocols, such as netFlow, sFlow, SPAN, RSPAN, CLI, LACP, 802.1ag, etc.

Software-defined Networking (Software-defined Networking) is a new type of innovative network architecture proposed by the Stanford University research group. Its core technology, OpenFlow, separates the control plane and data plane of network equipment, thereby giving network design planning and Management provides great flexibility and provides a good platform for core network and application innovation.

Contents of the invention

The object of the present invention is to propose an 802.11 wireless access network based on virtualization technology to overcome all or part of the defects of the prior art.

The technical solution adopted by the present invention to achieve its purpose is: the 802.11 wireless access network based on virtualization technology in the present invention includes a virtual access point and more than two physical access points, and the virtual access point includes a network capable of generating 802.11 data A virtualized wireless network card for frames, a first tunnel for encapsulating 802.11 data frames, and a virtual switch; the virtual wireless network card is connected to the virtual switch through the first tunnel; each of the physical access points includes a wired network card and a wireless network card and a second tunnel for encapsulating 802.11 data frames, the wired network card is connected to the wireless network card through the second tunnel, and the virtual switch is respectively connected to the wired network cards in each physical access point in a wired manner .

Further, the virtual switch in the present invention is an open virtual switching standard switch.

Further, the present invention further includes a software-defined network controller, and the software-defined network controller is connected to the virtual switch.

Further, the first tunnel of the present invention includes a tunnel encapsulation table; on the one hand, when the first tunnel receives a data packet from a new mobile terminal through the physical access point for the first time, the Ethernet data frame from the virtual switch is decapsulated into 802.11 data frames and extract related information, the "related information" includes the IP address and physical address of the physical access point, and the physical address and signal strength of the new mobile terminal sending the data packet, the tunnel encapsulation table according to The extracted relevant information associates and records the new mobile terminal with the physical access point that receives the data packet of the mobile terminal; if the first tunnel receives a data packet that is not a new mobile terminal, the first tunnel The original association record of the tunnel encapsulation table judges whether the mobile terminal that sent the data packet is associated with the physical access point that received the data packet. If so, the first tunnel sends the data packet from the mobile terminal to the virtual wireless network card; if not associated, then discard the data packet; on the other hand, when the first tunnel receives the 802.11 data frame generated by the virtual wireless network card, extract the frame header information of the 802.11 data frame, and according to the frame header information Determine the physical access point associated with the destination mobile terminal of the 802.11 data frame with the original association record of the tunnel encapsulation table, and use the IP address and physical address of the physical access point as the destination IP address and the physical address of the encapsulation header. The destination physical address encapsulates the 802.11 data frame, and then sends the encapsulated 802.11 data frame to the virtual switch.

Compared with the prior art, the beneficial effect of the present invention is: the present invention realizes "multiple virtual one" virtualization and multiple access points of 802.11 wireless access points by virtualizing more than two physical access points into one virtual access point. Unified management of point virtualization, seamless switching of mobile terminals among multiple access points, etc. If the virtual switch further adopts an open virtual switching standard switch and is connected to a software-defined network controller, the software-defined network controller can also control the data flow table of the 802.11 wireless access network, realize flexible control of network traffic, and effectively and conveniently manage and Configure the wireless access network; write various applications through the open platform on the controller, and realize various network configuration functions, such as detecting the traffic conditions of mobile terminals and access points in a dynamic virtual environment, fine-grained quality of service, Port-based traffic policy load balancing, dynamic real-time traffic monitoring, firewall, gateway and wireless link monitoring, etc. Therefore, the wireless access network of the present invention supports different application scenarios, realizes cross-layer network virtualization from the 802.11 wireless interface layer to the network interface layer, the Internet layer, and the transport layer, realizes full network virtualization configuration, and simplifies the network topology. It facilitates unified management and planning, and can provide a basis for network-wide optimization.

Description of drawings

Fig. 1 is a structural representation of the present invention;

Fig. 2 is a schematic layout diagram of a practical application of the present invention.

Detailed ways

As shown in Fig. 1, the 802.11 wireless access network based on the virtualization technology of the present invention includes one virtual access point and more than two physical access points. Wherein, the virtual access point includes a virtualized wireless network card capable of generating 802.11 data frames, a first tunnel for encapsulating 802.11 data frames, and a virtual switch; the virtual wireless network card is connected to the virtual switch through the first tunnel. Each physical access point includes a wired network card, a wireless network card and a second tunnel for encapsulating 802.11 data frames. In each physical access point, the wired network card is connected to the wireless network card through the second tunnel, and the virtual switch is respectively connected to the wired network cards in each physical access point in a wired manner. The implementation and functions of each part are described below with specific embodiments.

1. Virtual access point

As shown in FIG. 1 , the virtual access point includes a virtualized wireless network card capable of generating 802.11 data frames, a first tunnel for encapsulating 802.11 data frames, and a virtual switch. The carrier of the virtual access point may be electronic equipment such as a computer, a switch, and a router. On the virtual access point, virtualize the 802.11 virtual wireless network card through software, and configure the virtual wireless network card channel, service set identification number, authentication method, access point working mode, etc., so that it can receive and send 802.11 data frames. A virtual switch implements a virtual switch through virtualization technology and is used to bridge physical interfaces. It can bind several Ethernet interfaces to bridge them. The first tunnel encapsulating the 802.11 data frame adopts the tunnel encapsulation technology with the 802.11 data frame as the payload, such as the layer-3 tunnel encapsulation of 802.11MAC_over_IP or the layer-2 tunnel encapsulation of 802.11MAC_over_MAC. One end of the first tunnel is connected to the virtual wireless network card of the virtual access point, and the other end is connected to the virtual switch.

On the one hand, when the first tunnel receives a data packet from a new mobile terminal through the physical access point for the first time, it decapsulates the Ethernet data frame from the virtual switch into an 802.11 data frame and extracts relevant information, the "related information" Including the IP address and physical address of the physical access point, and the physical address and signal strength of the new mobile terminal sending the data packet, the tunnel encapsulation table connects the new mobile terminal with the receiving mobile terminal according to the extracted related information The physical access point of the data packet of the terminal is associated with the record; if the data packet received by the first tunnel is not a new mobile terminal, the first tunnel judges the mobile terminal that sent the data packet according to the original association record of its tunnel encapsulation table. Whether the terminal is associated with the physical access point that received the data packet, if associated, the first tunnel sends the data packet from the mobile terminal to the virtual wireless network card; if not associated, the data packet is discarded; the other In one aspect, when the first tunnel receives the 802.11 data frame generated by the virtual wireless network card, the frame header information of the 802.11 data frame is extracted, and the 802.11 data is determined according to the frame header information and the original associated record of the tunnel encapsulation table The physical access point associated with the destination mobile terminal of the frame, and encapsulate the 802.11 data frame with the IP address and physical address of the physical access point as the destination IP address and destination physical address of the encapsulation header, and then encapsulate the 802.11 data frames are sent to the virtual switch. The virtual switch forwards the data frame to the corresponding physical access point by checking its own forwarding table.

2. Physical access point

As shown in FIG. 1 , each physical access point includes a wired network card, a wireless network card, and a second tunnel for encapsulating 802.11 data frames. In each physical access point, the wired network card is connected to the wireless network card through the second tunnel. The virtual switch of the virtual access point is connected to the wired network card in each physical access point through a wired method. The wireless network cards of each physical access point work in monitoring mode. The working frequency band of the wireless network card is the same as that of the virtual network card of the virtual access point, and receives all 802.11 wireless data frames under this frequency band within the coverage area. The wireless network card of each physical access point is configured with a wireless interface. When a mobile terminal sends an 802.11 data frame to the wireless network card of the physical access point, the wireless interface sends an 802.11 real-time confirmation frame to the mobile terminal through the wireless network card, indicating wireless access point has received the frame. The second tunnel encapsulating the 802.11 data frame adopts the tunnel encapsulation technology with the 802.11 data frame as the payload, for example, the layer-3 tunnel encapsulation technology of 802.11MAC_over_IP or the layer-2 tunnel encapsulation technology of 802.11MAC_over_MAC. One end of the second tunnel is connected to the wireless network card, and the other end is connected to the wired network card. When the wireless network card receives the 802.11 data packet, it sends it to the second tunnel that encapsulates the 802.11 data frame, and the second tunnel filters the received 802.11 data frame according to the relevant information of the virtual access point, and the data frame that does not belong to the virtual access point Point data frames are discarded, reducing unnecessary network overhead. The filtered 802.11 data frame is encapsulated into an Ethernet data packet in the second tunnel, sent to the wired network card, and sent to the virtual access point in a wired manner. The data packet received by the wired network card from the virtual access point is directly forwarded to the second tunnel, and the second tunnel decapsulates the data packet sent by the wired network card into an 802.11 data packet, and forwards it to the wireless network card, and the wireless network card transmits the 802.11 data frame sent to the mobile terminal.

In the present invention, since the IEEE802.11 authentication and association status of the mobile terminal are only stored in the virtual access point, when the mobile terminal moves within the signal coverage of the physical access point, only the physical access point is triggered. Traffic switching between points does not trigger the 802.11 standard switching process. For the mobile terminal, the associated wireless access point is a virtual access point, and there is no 802.11 standard handover between physical access points for the mobile terminal. Therefore, the traffic switching process between the physical access points is transparent to the mobile terminal, and the switching of the mobile terminal between the physical access points will not cause interruption of network services. The switching process is described in detail below.

Referring to FIG. 1, when a mobile terminal moves from one physical access point 1 to another physical access point 2, the signal strength of the mobile terminal detected by the physical access point 1 is continuously weakened, and the physical access point 2 detects The signal strength of the mobile terminal continues to increase. Information such as the signal strength of the access point detected by the physical access point is included in the 802.11 Radiotap frame header of the 802.11 data frame. When the 802.11 data frame sent by the mobile terminal is encapsulated by the second tunnel of the physical access point and sent to the first tunnel of the virtual access point, the first tunnel extracts information such as signal strength in the header of the 802.11 Radiotap frame and records it In the self-tunnel encapsulation table. The virtual access point compares the signal strength between each physical access point and the mobile terminal in real time, so as to automatically control the traffic switching between the physical access points. When the physical access point 2 detects that the difference between the signal strength of a terminal associated with the physical access point 1 and the signal strength detected by the physical access point 1 reaches the preset threshold Signal _TH , the physical access is triggered switching process between points. The threshold Signal _TH of the signal strength difference triggering the handover process has a default value of 50 dBm according to experience, and technicians can adjust the threshold value of the signal strength difference according to the requirement of handover sensitivity. Since the association between the mobile terminal and the physical wireless access point is determined by the first tunnel, and the communication path between the virtual access point and the mobile terminal is selected by the first tunnel, the first tunnel completes the physical access of the mobile terminal. Switching between points only needs to change the associated physical access point of the mobile terminal from physical access point 1 to physical access point 2, so that the traffic of the mobile terminal is transferred from physical wireless access point 1 to physical access point In point 2, the switching process is completed. The handover process is transparent to the mobile terminal. This handover process can be applied in different scenarios, such as traffic balancing and mobility management. In addition, the first tunnel can close the tunnel channel of a certain physical access point, so that the data packets generated by the virtual wireless network card cannot reach the physical access point, reduce the transmission power consumption of the physical access point and reduce the interference to the space wireless spectrum resources .

FIG. 2 is a schematic layout diagram of a practical application of the present invention. Considering the fading effect of indoor wireless channels and the blocking of wireless channels by indoor walls, a physical access point can be placed in each room that needs wireless access, and a virtual access point can be placed in the room. During the layout, technicians should reasonably configure the signal coverage of each physical access point, so that the signal coverage area of the physical access point is limited to each room, and try to ensure that the signal coverage of each physical access point does not overlap. Since when the terminal is in the overlapping coverage area of the adjacent physical wireless access point, it can receive the signal of the physical wireless access point within the coverage area at the same time, so when the adjacent physical access point has data packets to be sent at the same time, Due to signal collisions, the communication quality of the terminal will degrade. The present invention can limit the transmission power of each physical access point, so that the signal coverage range between each physical access point is limited within a certain range, and can effectively reduce the problem of signal overlapping areas. The invention can meet the wireless access requirements of indoor places such as families and hotels, can realize transparent and seamless switching, and can have great flexibility in coverage. If a mobile user moves from the room where physical access point 1 is located to the room where physical access point 2 is located, it can be detected that the signal between the user and physical access point 1 is getting weaker and weaker, and the signal between the user and physical access point 2 is weaker. The signals between the terminals are getting stronger and stronger. When the latter is higher than the former by a certain threshold, a rapid switching between physical access points is performed, and the associated physical access point of the terminal is switched from physical access point 1 to physical access point 2. The mobile terminal will not be aware of the handover process, and the seamless handover of the terminal between physical access points is realized, so that the user has a better experience.

The virtual switch can be Microsoft Hyper-V virtual switch, Cisco Nexus 1000, Linux kernel bridging and Open Virtual Switching standard switch (Open vSwitch). Among them, an open virtual switching standard switch is preferably used, which is a product-level quality multilayer virtual switching standard switch under the open source Apache2.0 license. It can be extended through programming to enable automatic network configuration, management and maintenance, and also supports standard management interfaces and protocols (such as NetFlow, sFlow, SPAN, RSPAN, CLI, LACP, 802.1ag, OpenFlow, etc.).

When the virtual switch in the present invention uses an open virtual switching standard switch (Open vSwitch), the open virtual switching standard switch can be connected with a software-defined network (Software-defined Networking) controller, so that the present invention can realize a software-defined network manage. The software-defined network controller may be a controller supporting the OpenFlow protocol, such as Floodlight, OpenDaylight, NOX, and POX. The software-defined network controller can control the flow entry of the open virtual switching standard switch through the OpenFlow protocol, so that the network traffic can be managed and controlled. Through the open interface platform on the software-defined network controller, technicians can write various open applications to realize various network configuration functions, such as load balancing, network service quality assurance, traffic monitoring, firewall, gateway, DHCP, wireless link monitoring, etc. Various custom functions. Therefore, the open application on the software-defined network controller can dynamically control and manage the flow table of the open virtual switching standard switch, so that the wireless access network of the present invention can adapt to different application scenarios, and realize from the 802.11 wireless interface layer to the network interface layer, Multi-layer cross-layer network virtualization such as Internet layer and transport layer. Similarly, the software-defined network controller can obtain real-time topology information of the entire network, and the controller can dynamically adjust the configuration of the network without manual intervention, realize the automatic configuration of full virtualization of the network, and unify management and planning, which can provide a basis for the optimization of the entire network .

Claims (3)

1. a kind of 802.11 wireless access network systems based on virtualization technology, it is characterized in that：Including a virtual access point and Two or more physical access point, the virtual access point include that the virtualization wireless network card of 802.11 data frames can be produced, use In the first tunnel and virtual switch that encapsulate 802.11 data frames；Virtual radio network interface card passes through first tunnel and the void Intend interchanger connection；Each physical access point include wired network adapter, wireless network card and for encapsulating 802.11 data frames the Two tunnels, the wired network adapter are connected by second tunnel with the wireless network card, and the virtual switch passes through wired Mode is connected with the wired network adapter in each physical access point respectively；

First tunnel includes tunnel encapsulation table；On the one hand, when the first tunnel is received from new first by physical access point Mobile terminal data packet when, the ethernet data frame of self-virtualizing interchanger unsealed and into 802.11 data frames and extracted phase future Close information, the IP address and physical address of " relevant information " including physical access point and send the new of the data packet The physical address and signal strength of mobile terminal, the tunnel encapsulation table is according to the relevant information extracted by the new mobile end The physical access point of data packet of the end with receiving the mobile terminal is associated record；What if the first tunnel received is not new The data packet of mobile terminal, then the first tunnel according to original associated record of its tunnel encapsulation table judge send the data packet shifting Whether dynamic terminal is associated with receiving the physical access point of the data packet, if associated, the first tunnel will come from mobile whole The data packet at end is sent to virtual radio network interface card；If unconnected, the data packet is abandoned；On the other hand, when the first tunnel When receiving 802.11 data frame of virtual radio network interface card generation, the frame header information of 802.11 data frames is extracted, and according to this Original associated record of frame header information and the tunnel encapsulation table determines that the purpose mobile terminal of 802.11 data frame is closed The physical access point of connection, and the purpose IP address and mesh on encapsulation head are used as using the IP address of the physical access point and physical address Physical address encapsulate 802.11 data frame, 802.11 data frames after encapsulation are then sent to virtual switch again.

2. 802.11 wireless access network systems according to claim 1 based on virtualization technology, it is characterized in that：The void It is open virtual switch standard switchboard to intend interchanger.

3. 802.11 wireless access network systems according to claim 2 based on virtualization technology, it is characterized in that：Further include Software defined network controller, the software defined network controller are connected with the virtual switch.