CN105610617A - QoS management mechanism for distinguishing user priorities in WLAN based on SDN and AP (Access Point) virtualization technique - Google Patents

Abstract

The invention discloses a QoS management mechanism for distinguishing user priorities in WLAN, adopts SDN and AP virtualization technology, binds data of user terminals of different priorities to queues of different priorities at each port of an OpenFlow switch, and features It is carried out as follows: the sender sends data to the physical access point, the physical access point converts the 802.11 data frame into an Ethernet frame and sends it to the OpenFlow switch, and the OpenFlow switch forwards the data from the specified queue of the specified port according to the matching flow entry , if there is no matching flow entry, the data will be sent to the central controller, and the central controller will decide how to process the data. The present invention binds data of user terminals of different priorities to queues of different priorities for forwarding through an OpenFlow switch, and can realize QoS management for differentiating user priorities, so that user terminals of different priorities can obtain different QoS experiences.

Description

A QoS Management Mechanism Based on SDN and AP Virtualization Technology to Differentiate User Priority in WLAN

technical field

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

Background technique

A wireless local area network (WLAN) refers to a computer network that uses wireless channels as a transmission medium. By using WLAN, users can realize broadband network access anytime and anywhere. With the development and wider application of WLAN, more and more people start to use WLAN to access the network through a wireless access point (Access Point, AP).

The 802.11 standard is widely used in WLANs. The 802.11 standard is formulated by the Institute of Electrical and Electronics Engineers (IEEE), and standardizes the physical layer (PHY) and media access control layer (MAC) of WLAN. However, the traditional 802.11 technology does not have built-in support for QoS, which makes IEEE802.11 WLAN encounter great challenges in providing services that require QoS guarantees such as audio. 802.11 specifies two MAC layer access mechanisms: distributed coordination function (DistributedCoordinationFunction, DCF) and point coordination function (PointCoordinationFunction, PCF). DCF is currently the most widely used MAC layer access mechanism. Each station uses a carrier sense/collision avoidance (CSMA/CA) distributed access method, and each station obtains the channel access right through free competition. The DCF mode does not distinguish between service types, and all services compete for channels under the same priority, and only provide "best effort" service without any QoS guarantee.

In order to support QoS more effectively, the IEEE802.11 task group proposed the 802.11e protocol. In this protocol, all services are divided into 4 access types, and 8 service flows are introduced to distinguish user priorities. IEEE802.11e extends the traditional 802.11 MAC layer DCF and PCF access mechanisms, forming the Enhanced Distributed Channel Access (EDCA) and Hybrid Control Channel Access (HCCA) specifications. EDCA enhances the DCF mechanism, differentiates the priorities of different service applications, guarantees the channel access capability of high-priority services, and guarantees the bandwidth of high-priority services to a certain extent; HCCA enhances the PCF mechanism, through the access point (QoSSupportingAP, QAP) The centralized control provides improved access bandwidth and reduces the delay of high-priority services. The IEEE802.11e protocol was passed in September 2005, but it has not yet been fully commercialized, and chip manufacturers only support a small number of features. Therefore, there is currently no technology that can properly solve the QoS management problem of differentiating user priorities in WLAN.

Currently, the concepts of software-defined networking (SDN) and network function virtualization have been widely adopted by many operators. SDN is an emerging software-based network architecture technology, and its core technology is OpenFlow technology. At present, the research on SDN is mainly concentrated in the wired network field. The research on wireless SDN is still in its infancy. For the research on the application of SDN to WLAN, most of the research is currently focused on the research of network architecture and the realization of seamless migration of user terminals. , there is no relevant research on the use of SDN to realize the QoS management guarantee mechanism in WLAN.

Contents of the invention

In order to overcome the deficiencies in the prior art, the present invention proposes a QoS management mechanism based on SDN and AP virtualization technology for distinguishing user priorities in WLAN, in order to realize the QoS service function for distinguishing user priorities and solve the existing problems. The WLAN network cannot provide QoS guarantees, so as to meet the QoS requirements of users with different priorities.

The technical scheme that the present invention realizes its object to take is:

A QoS management mechanism based on SDN and AP virtualization technology in the present invention that distinguishes user priorities in a WLAN is characterized in that: the WLAN includes several user terminals STA, a virtual access point VAP, at least one physical access point PAP, An OpenFlow switch and a central controller OFC;

Each port of the OpenFlow switch has multiple priority queues, and the bandwidth resources corresponding to each priority queue are allocated correspondingly according to the priority level; higher priority queues allocate higher bandwidth resources; The central controller OFC stores the priorities of the several user terminal STAs; defines the user terminal STA that sends the data frame as the sender; defines the user terminal STA that receives the data frame as the receiver;

Described QoS management mechanism carries out as follows:

Step 1. The sender sends an uplink 802.11 data frame to the physical access point PAP;

Step 2, the physical access point PAP receives and processes the uplink 802.11 data frame, converts it into an uplink Ethernet frame and sends it to the OpenFlow switch;

Step 3, the OpenFlow switch checks whether there is a flow entry matching the sender in the internal flow table according to the uplink Ethernet frame; if it exists, obtains the flow entry according to the action instruction in the flow entry The port through which the uplink Ethernet frame is to be sent, and the priority queue through which the uplink Ethernet frame is to be passed, so that the uplink Ethernet frame is sent from the corresponding priority queue of the corresponding port in the OpenFlow switch to the virtual access point VAP, and perform step 6; if it does not exist, then the OpenFlow switch directly packs the uplink Ethernet frame, converts it into a packet-in message and sends it to the central controller OFC;

Step 4, the central controller OFC queries the priority of the sender corresponding to the uplink Ethernet frame according to the packet-in message; and sends a corresponding flow entry to the OpenFlow switch according to the obtained priority ;

Step 5, the OpenFlow switch adds the received flow entry to the flow table, thereby updating the flow table; the OpenFlow switch obtains the information to be sent by the uplink Ethernet frame according to the action indication in the received flow entry port, and the priority queue through which the uplink Ethernet frame is to be passed, so that the uplink Ethernet frame is sent to the virtual access point VAP from the corresponding priority queue of the corresponding port in the OpenFlow switch;

Step 6, the virtual access point VAP receives the uplink Ethernet frame, restores the uplink Ethernet frame into the uplink 802.11 data frame and performs logical processing of the 802.11 protocol, generates a downlink 802.11 data frame and repackages and converts it into a downlink Ethernet frame and send it to the OpenFlow switch;

Step 7. The OpenFlow switch checks the internal flow table for a flow entry matching the receiver according to the downlink Ethernet frame; if it exists, obtains the flow entry according to the action instruction in the flow entry. The port to be sent by the downlink Ethernet frame, and the priority queue to be passed, so that the downlink Ethernet frame is sent to the physical access point PAP from the corresponding priority queue of the corresponding port in the OpenFlow switch, and the steps are performed 10. If it does not exist, the OpenFlow switch directly packages the downlink Ethernet frame, converts it into a new packet-in message and sends it to the central controller OFC;

Step 8, the central controller OFC queries the priority of the corresponding receiver according to the new packet-in message; and sends a corresponding flow entry to the OpenFlow switch according to the obtained priority;

Step 9, the OpenFlow switch adds the received flow entry to the flow table, thereby updating the flow table; the OpenFlow switch obtains the information to be sent by the downlink Ethernet frame according to the action indication in the received flow entry port, and the priority queue to be passed, so that the downlink Ethernet frame is sent to the physical access point PAP from the corresponding priority queue of the corresponding port in the OpenFlow switch;

Step 10, the physical access point PAP processes the received downlink Ethernet frame, converts it into a downlink 802.11 data frame and sends it to the receiver, thereby completing QoS management for differentiating user priorities.

The characteristics of the QoS management mechanism for distinguishing user priorities in the WLAN of the present invention are also:

The flow table is composed of several flow table items, and each flow table item is composed of three parts: a matching field, an action field, and a counter;

The matching field includes: an ingress port number, a destination IP address, a source IP address, a destination MAC address, and a source MAC address;

The action domain includes: a forwarding port and its corresponding forwarding queue;

The counter is used to count the number of times the flow entry is matched.

The physical access point PAP adds an uplink Ethernet frame header of at least 14 bytes to the uplink 802.11 data frame, thereby converting it into an uplink Ethernet frame;

At the same time, the physical access point PAP removes the downlink Ethernet frame header from the downlink Ethernet frame, thereby converting it into a downlink 802.11 data frame.

Compared with the prior art, the beneficial effects of the present invention are reflected in:

1. The mechanism of the present invention introduces the network architecture of the SDN concept, separates the logical function of the AP from the data forwarding function through the AP virtualization technology, virtualizes multiple physical APs into one virtual AP, and sets different priorities in the OpenFlow switch Queues of different priorities are assigned different bandwidths, and user data of different priorities are forwarded from queues of corresponding priorities, thus satisfying the QoS requirements of users of different priorities and realizing QoS guarantee for distinguishing user priorities.

2. In the present invention, the OpenFlow switch forwards the data of different priority users from different priority queues, thereby ensuring the user's QoS requirements; the forwarding rules of the OpenFlow switch are determined by the central controller, and the central controller writes software The application method realizes the user's QoS guarantee. When the user's priority changes, the controller can modify the user's data flow by modifying the flow table, realizing the flexible and fast guarantee of the user's QoS requirement.

3. In the present invention, the central controller manages all physical APs, and can guarantee the QoS requirements of users according to the global information of the network. When a certain physical load is too heavy to guarantee the QoS of the currently connected users, the central controller can The global information, combined with the user switching strategy, binds the user data flow to the physical AP that can meet the user's QoS requirements, thereby better guaranteeing the user's QoS requirements.

4. In the present invention, the OpenFlow control determines how to process data directly according to the action indication in the flow table item according to the matching and searching of the flow table item in the flow table item and the flow table item matching with the user terminal STA. The management and control of the flow is very flexible and easy. implementation, while enabling finer-grained control over data traffic with the help of match domains containing multiple sets of matches.

5. In the present invention, the WLAN wireless data frame is converted into an Ethernet frame, so that the OpenFlow switch can process wireless data flexibly in the manner of processing wired data, which makes up for the defect that OpenFlow cannot process wireless data frames.

Description of drawings

Fig. 1 is a schematic diagram of the architecture of the present invention;

Fig. 2 is the queue diagram of port in the OVS of the present invention;

Fig. 3 is a schematic diagram of implementing QoS guarantee for two users in the present invention.

detailed description

In order to describe the advantages of the technical solution of the present invention more clearly, the specific embodiment of the present invention will be further elaborated below in conjunction with the accompanying drawings. In this specific embodiment, the user priority is set to 3 levels, and queue 1 is high. Priority queues have the highest bandwidth resources, queue 2 is a medium priority queue, and queue 3 is a low priority queue. It should be noted that the setting of priorities is not limited to three, and technicians can set multiple priority queues according to actual needs.

The present invention is based on the QoS management mechanism for distinguishing user priorities in WLAN based on SDN and AP virtualization technology, and uses SDN and AP virtualization technology to bind the data of user terminals with different priorities to queues with different priorities at each port of the OpenFlow switch In general, a WLAN includes several user terminal STAs, a VAP, at least one PAP, a central controller OFC and an OpenFlow switch for connecting them. Wired connections are used between the OpenFlow switch and the virtual access point VAP, between the OpenFlow switch and the physical access point PAP, and between the OpenFlow switch and the central controller OFC, and the user terminal STA accesses the physical access point PAP through a wireless channel. .

Each port of the OpenFlow switch has a variety of priority queues, and the bandwidth resources corresponding to each priority queue are allocated according to the priority; higher priority queues allocate higher bandwidth resources; the central controller OFC The priorities of the several user terminal STAs are stored in ; the user terminal STA that sends data frames is defined as the sender; the user terminal STA that receives data frames is defined as the receiver. As shown in Figure 1, the specific description of each part is as follows:

1. Virtual Access Point VAP

The virtual access point VAP virtualizes a wireless network card, generates beacon frames, and processes 802.11 data frames, which are used for association authentication with the user terminal STA. At the same time, the dhcp component of the VAP will assign an IP address to the user terminal STA connected to the virtual access point VAP. At the same time, the virtual access point VAP encapsulates the 802.11 data frame sent by it through the tunnel into an Ethernet frame and sends it to the physical access point PAP through the OpenFlow switch. Similarly, after the virtual access point VAP receives the Ethernet frame forwarded by the OpenFlow switch It will be decapsulated into 802.11 frames through the tunnel and then related processing.

2. Physical Access Point PAP

The physical access point PAP has a wired network card, a wireless network card and a tunnel connecting the two network cards. The wired network card is connected to the OpenFlow switch. When the wireless network card receives the data frame, the data frame will be sent to the wired network card through the tunnel. At the same time, the tunnel will encapsulate the 802.11 data packet into an Ethernet data frame, and the encapsulated Ethernet data frame will be sent to the wired network card. The OpenFlow switch is further forwarded to the virtual access point VAP or the central controller OFC for processing. Similarly, the data frames sent by the virtual access point VAP to the physical access point PAP through the OpenFlow switch will be decapsulated into 802.11 data frames by the tunnel and then sent to the wireless network card and sent to the receiver.

3. OpenFlow switch

In this embodiment, the OpenFlow switch is realized by using the software switch OVS. The OpenFlow switch connects the virtual access point VAP and the physical access point PAP in a wired manner and undertakes the task of data forwarding between the two, while being controlled by the central controller OFC. The two wired ports of the OpenFlow switch connecting the virtual access point VAP and the physical access point PAP are each equipped with three queues with high, medium and low priorities, as shown in Figure 1 and Figure 2. Each queue is allocated different bandwidth resources. In the specific implementation, the internal flow table of the OpenFlow switch is composed of several flow table items, and each flow table item is composed of three parts: a matching field, an action field, and a counter;

The matching field includes: ingress port number, destination IP address, source IP address, destination MAC address, source MAC address;

The action domain includes: forwarding ports and their corresponding forwarding queues;

Counters are used to count the number of times a flow entry is matched.

4. Central controller OFC

In this embodiment, the central controller OFC is implemented by the OpenFlow controller POX. The central controller OFC stores the priority information of the registered user terminal STA. When the central controller OFC receives the packet-in message forwarded by the OpenFlow switch, it obtains the MAC address information of the user terminal STA by parsing the packet-in message, and according to the stored The user priority information obtains the priority of the user terminal STA, so that the data flow of the user terminal STA is allocated to the queue of the specified priority, and the user terminal STAs with different user priorities can obtain different bandwidth resources. And the central controller OFC can easily and flexibly change the forwarding rules of the OpenFlow switch, so that the service level enjoyed by each user terminal STA can be adjusted at any time.

The implementation process of the QoS guarantee is described in detail below.

Step 1. The sender sends an uplink 802.11 data frame to the WLAN;

Step 2, the physical access point PAP receives the uplink 802.11 data frame and processes it, adds an Ethernet frame header to the received 802.11 wireless data frame head, converts the 802.11 wireless data frame into an uplink Ethernet frame and sends it to the OpenFlow switch;

Step 3. The OpenFlow switch receives the uplink Ethernet frame sent by the physical access point PAP, and checks whether there is a flow entry matching the sender in the internal flow table; if it exists, obtain it according to the action instruction in the flow entry The port to which the uplink Ethernet frame is to be sent, and the priority queue through which the uplink Ethernet frame is to be passed, so that the uplink Ethernet frame is sent to the virtual access point VAP from the corresponding priority queue of the corresponding port in the OpenFlow switch, and Execute step 6; if it does not exist, the OpenFlow switch directly packs the uplink Ethernet frame, converts it into a packet-in message and sends it to the central controller OFC;

Step 4, the central controller OFC analyzes the packet-in message according to the received packet-in message, obtains the MAC address of the sender, and obtains the sender's address corresponding to the MAC address by querying the priority information of the user terminal STA stored locally. priority, and send the corresponding flow entry to the OpenFlow switch according to the obtained priority, which indicates the port to which the uplink Ethernet frame is to be sent and the priority queue to pass through;

Step 5, the OpenFlow switch adds the received flow entry to the flow table, thereby updating the flow table; the OpenFlow switch obtains the port to send the uplink Ethernet frame according to the action indication in the received flow entry, and the uplink Ethernet frame The priority queue to be passed by the network frame, so that the uplink Ethernet frame is sent to the virtual access point VAP from the corresponding priority queue of the corresponding port in the OpenFlow switch;

Step 6, the virtual access point VAP receives the uplink Ethernet frame, restores the uplink Ethernet frame into an uplink 802.11 data frame and processes it, generates a downlink 802.11 data frame and repackages and converts it into a downlink Ethernet frame and sends it to the OpenFlow switch;

Step 7. The OpenFlow switch checks the internal flow table for a flow entry matching the receiver according to the downlink Ethernet frame; if it exists, obtains the port through which the downlink Ethernet frame is to be sent according to the action instruction in the flow entry , and the priority queue to be passed, so as to send the downlink Ethernet frame from the corresponding priority queue of the corresponding port in the OpenFlow switch to the physical access point PAP, and perform step 10; if it does not exist, the OpenFlow switch directly sends the downlink Ethernet frame The Ethernet frame is packaged, converted into a new packet-in message and sent to the central controller OFC;

Step 8, the central controller OFC receives a new packet-in message, parses the packet-in message, obtains the MAC address of the receiver, queries the priority information of the user terminal STA stored locally according to the new packet-in message, and obtains the The priority of the receiver corresponding to the MAC address; and send the corresponding flow entry to the OpenFlow switch according to the obtained priority, the flow entry indicates the port to be sent by the downlink Ethernet frame and the priority queue to be passed;

Step 9, the OpenFlow switch adds the received flow entry to the flow table, thereby updating the flow table; the OpenFlow switch obtains the port to be sent by the downlink Ethernet frame and the port to pass through according to the action indication in the received flow table entry. A priority queue, so that the downlink Ethernet frame is sent to the physical access point PAP from the corresponding priority queue of the corresponding port in the OpenFlow switch;

Step 10, the physical access point PAP processes the received downlink Ethernet frame, removes the downlink Ethernet frame header, converts the received downlink Ethernet frame into a downlink 802.11 data frame and sends it to the receiver, thereby completing the distinction QoS management for user priority. The present invention binds data of user terminals of different priorities to queues of different priorities for forwarding through an OpenFlow switch, and can realize QoS management for differentiating user priorities, so that user terminals of different priorities can obtain different QoS experiences.

Specifically, as shown in FIG. 3 , the user priorities are divided into three levels. The user priorities of the user terminal STA1 and the user terminal STA2 are respectively 1 and 3. The central controller OFC stores the MAC addresses of STA1 and STA2 and the corresponding User priority information. When STA1 requests to connect to the physical PAP, because STA1 is requesting to access the network for the first time, there is no matching flow entry in the OpenFlow switch, and the OpenFlow switch sends the information of STA1 to the central controller OFC through a packet-in message, The central controller OFC obtains the MAC address of STA1 by analyzing the packet-in message, obtains the user priority of STA1 as 1 according to the stored user terminal priority information, and allocates a corresponding flow table for STA1 according to the user priority information of STA1, Bind the data flow of STA1 to queue 1 with high priority. Similarly, the central controller binds the data flow of STA2 to queue 3 with low priority. Two dotted lines show the data forwarding path between STA1 and STA2 and the virtual access point VAP. According to this path, the QoS obtained by STA1 with high priority will be better than the QoS obtained by STA2 with low priority .

Claims (3)

1. in the WLAN based on SDN and AP Intel Virtualization Technology, distinguish a QoS administrative mechanism for User Priority, its spyLevy and be: described WLAN comprise some user terminal STA, virtual access point VAP, at least one physical access point PAP,An OpenFlow switch and a master controller OFC;

Each port of described OpenFlow switch has multiple priorities queue, the corresponding bandwidth of Mei Zhong priority queryResource is distributed accordingly according to the height of priority; The higher bandwidth resources of queue assignment that priority is higher; Described centerIn controller OFC, store the priority of described some user terminal STA; The user terminal STA that definition sends Frame isTransmit leg; The user terminal STA of definition receiving data frames is recipient;

Described QoS administrative mechanism is carried out as follows:

Step 1, described transmit leg send up 802.11 Frames to described physical access point PAP;

Step 2, described physical access point PAP receive described up 802.11 Frames and process, and are converted to up etherNet frame is also sent to described OpenFlow switch;

Whether step 3, described OpenFlow switch, according to described up ethernet frame, are inquired about in inner stream table and are existed and instituteState the stream list item that transmit leg matches; If exist, obtain described up ethernet frame according to the action instruction in stream list item and wantThe port sending, and the described up ethernet frame priority query that will pass through, thus by described up ethernet frame from instituteState in the respective priority queue of corresponding port in OpenFlow switch and be sent to described virtual access point VAP, and carry out stepRapid 6; If do not exist, described OpenFlow switch is directly packed described up ethernet frame, is converted to packet-inMessage sends to described master controller OFC;

Step 4, described master controller OFC are according to corresponding of up ethernet frame described in described packet-in information queryThe priority of the side of sending; And send corresponding stream list item according to obtained priority to described OpenFlow switch;

Step 5, described OpenFlow switch add received stream list item in stream table to, thereby upgrade stream table; DescribedOpenFlow switch obtains according to the action instruction in received stream list item the port that described up ethernet frame will send,And the described up ethernet frame priority query that will pass through, thereby by described up ethernet frame from described OpenFlowIn switch, in the respective priority queue of corresponding port, be sent to described virtual access point VAP;

Step 6, described virtual access point VAP receive described up ethernet frame, described in described up ethernet frame is reduced intoUp 802.11 Frames also carry out the logical process of 802.11 agreements, generate descending 802.11 Frames and repack to convert toDownlink Ethernet frame also sends to described OpenFlow switch;

Whether step 7, described OpenFlow switch, according to described downlink Ethernet frame, are inquired about in inner stream table and are existed and instituteState the stream list item that recipient matches; If exist, obtain described downlink Ethernet frame according to the action instruction in stream list item and wantThe port sending, and the priority query that will pass through, thus described downlink Ethernet frame is exchanged from described OpenFlowIn machine, in the respective priority queue of corresponding port, be sent to physical access point PAP, and perform step 10; If do not exist, instituteState OpenFlow switch and directly described downlink Ethernet frame is packed, be converted to new packet-in message and send to instituteState master controller OFC;

Step 8, described master controller OFC are according to the described new corresponding recipient's of packet-in information query priority;And send corresponding stream list item according to obtained priority to described OpenFlow switch;

Step 9, described OpenFlow switch add received stream list item in stream table to, thereby upgrade stream table; DescribedOpenFlow switch obtains according to the action instruction in received stream list item the port that described downlink Ethernet frame will send,And the priority query that will pass through, thereby by described downlink Ethernet frame corresponding port from described OpenFlow switchRespective priority queue in be sent to physical access point PAP;

Step 10, described physical access point PAP process received downlink Ethernet frame, are converted to descending 802.11Frame also sends to recipient, thereby completes the QoS management of distinguishing User Priority.

2. the QoS administrative mechanism of distinguishing User Priority in WLAN according to claim 1, is characterized in that, described inStream table is made up of several stream list items, and each stream list item is made up of matching domain, action fields, three parts of counter;

Described matching domain comprises: inbound port number, object IP address, source IP address, target MAC (Media Access Control) address, source MAC;

Described action fields comprises: forward port and corresponding forwarding queue thereof;

Described counter is for adding up the number of times that described stream list item is matched.

3. the QoS administrative mechanism of distinguishing User Priority in WLAN according to claim 1, is characterized in that, described inPhysical access point PAP is the up Ethernet frame head that described up 802.11 Frames is added at least 14 bytes, thus conversionFor up ethernet frame;

Meanwhile, described downlink Ethernet frame is removed downlink Ethernet frame head by described physical access point PAP, thereby be converted to downRow 802.11 Frames.