CN105530204A - Novel structure and method for guaranteeing video service QoS in software-defined wireless network - Google Patents

Abstract

The invention provides a novel wireless network construction scheme based on software-defined network technology, so as to guarantee the QoS of video stream in a wireless network. A controller issues a message to each AP by means of the centralized management ability on all AP in the whole network, the AP broadcasts the information per se on a working channel, monitors the information of the neighbor AP on each channel and uploads the information to the controller at least, and the controller summarizes the information to obtain a neighbor information table of the global AP, so as to reasonably allocate wireless channels and avoid resource waste of the wireless channels; on this basis, the video stream is marked at a service outlet, then queues with different bandwidths are arranged on each AP, and the controller judges whether the video stream exists by identifying a mark on a data packet, and finally sets a queue with higher priority and larger bandwidth for the video stream by issuing the flow table, as long as the two points are realized, the effective transmission of the video stream can be guaranteed, and the user experience is improved.

Description

The novel framework that in software definition wireless network, video traffic QoS ensures and method

Technical field

The present invention is based on software defined network framework, belong to the virtual field of network function, particularly relate to and utilize Intel Virtualization Technology to build wireless network, and under the centralized control of network controller to full mesh topology, implementation strategy realizes ensureing the QoS of video flowing.

Background technology

The convenience of WLAN (wireless local area network) and flexibility can be deployed in family widely, and enterprises, even in campus network, compares cable broadband, and people are more ready wirelessly to surf the Net.The high speed development of the Internet creates various service, people are more and more accustomed to carrying out the Internet shopping by the mode of access wireless aps (AccessPoint), communication and viewing video, particularly when by wireless network viewing Online Video, the lifting of video quality exacerbates the demand of user to bandwidth, when the access AP in same wireless network coverage gets more and more, adjacent AP accesses identical wireless channel will be congested, also have, when various demand for services increases, these serve the rate of discharge produced can take a large amount of bandwidth of wireless aps, these problems all can make the Consumer's Experience watching video poor.In the face of these problems, traditional wireless local planar network architecture solves and gets up can seem unable to do what one wishes, and main cause is the limitation that the networking mode of traditional wireless office net brings.

The networking mode of traditional WLAN (wireless local area network) is divided into fat AP and thin AP+AC (AccessController, wireless controller).Wherein, the mode of fat AP builds wireless aps in a distributed manner, these AP self have access authentication, DHCP (dynamic assignment IP), the functions such as fire compartment wall, the shortcoming of this networking mode is, when network management personnel's implementation strategy, need to understand the information of each AP and be configured each AP one by one, cannot manage concentratedly, workload more greatly and easily make mistakes; The mode of thin AP+AC is the management of being concentrated wireless aps by AC, implementation strategy, such as access authentication, QoS etc., and AP is just for user provides the forwarding channel of flow, the defect of this mode is the strategy formulated on AC is static, AC cannot dynamic self-adapting network change and make corresponding Developing Tactics, and AC equipment manufacturing cost is higher, if the larger words of network are also higher to the performance requirement of equipment.From traditional WLAN networking mode, main defect is centralized management difficulty, cannot dynamic self-adapting network change and equipment manufacturing cost and performance requirement higher.At this moment, researcher is had to propose to utilize the technology of software defined network to solve many confinement problems of conventional WLAN.ONF (OpenNetworkingFoundation) proposes SDN Technology application in wireless network in nearest SDN official white paper (ONF.WirelessTransportSDNProofofConceptWhitePaper [J/OL] //https: //www.opennetworking.org), by SDN controller, each WAP (wireless access point) is managed concentratedly, effectively can implement the strategies such as raising radio transmission bandwidth sum traffic shaping.

Software defined network is a kind of network architecture based on software and technology, and its main thought is separated the control of the network equipment, managed by proprietary controller.The separation of control make network manager can self-defined underlay network device forwarding strategy and equipment is managed concentratedly.OpenFlow agreement is one of core technology of SDN, and in agreement, 2 parts of most critical are: OpenFlow switch and controller.In an OpenFlow network, the forwarding of OpenFlow switch primary responsibility data, main ins and outs have three parts: stream table, safe lane and OpenFlow agreement.Be implemented in WLAN (wireless local area network) by software defined network technology, the information of full mesh topology and each AP grasped by controller, unified management network according to the forwarding behavior of policy development AP.Because controller has the extendible characteristic of programming, so can expand to control module the strategy realizing different demand by the mode of programming, so just can solve existing problem in WLAN (wireless local area network), the QoS realizing video flowing ensures.

At present, existing researcher ensures based on the QoS for particular flow rate in SDN technical research wireless network.TomovicS is at (list of references: TomovicS, YoshigoeK, MaljevicI, etal.SDN-basedconceptofQoSawareheterogeneouswirelessnetw orkoperation [C] //TelecommunicationsForumTelfor (TELFOR), 201422nd.IEEE, propose 2014:27-30), controller utilizes DPI (Deeppacketinspection, deep message is resolved) technical Analysis first time by the COS of the packet of node, then issue stream show to node according to service type assignment amount of bandwidth.BivasBhattacharya is at (list of references: BhattacharyaB, DasD.SoftwareDefinedNetworkcontrollerembeddedinmobiledev iceforuser'spolicyimplementation [C] //IndustrialInstrumentationandControl (ICIC), 2015InternationalConferenceon.IEEE, propose 2015:1437-1441), according to the demand of user to different application, for priority is formulated in different application, node sets the bandwidth value that different priorities is corresponding, when the application of user produces flow by node, controller will come for assignment of traffic bandwidth according to the priority of this application.JonathanVestin is at (list of references: VestinJ, KasslerA.QoSenabledWiFiMAClayerprocessingasanexampleofaN FVservice [C] //NetworkSoftwarization (NetSoft), 20151stIEEEConferenceon.IEEE, propose 2015:1-9.), configure the queue of different priorities and bandwidth on an access point, classification and marking is carried out to flow, according to the corresponding queue of the subcarrier label assignments of flow.More than study the QoS that can realize video flowing to a certain extent to ensure, but they have ignored the co-channel interference in wireless network between AP mostly, even if an AP is that video flowing is assigned with very large bandwidth, user still can cause because of the co-channel interference between adjacent AP when watching video and not smoothly even to go offline.

Summary of the invention

For following existing deficiency, propose a kind of ensure screen stream effective transmission, reach wireless channel reasonable distribution software definition wireless network in the novel framework that ensures of video traffic QoS and method.。Technical scheme of the present invention is as follows: the novel framework that in a kind of software definition wireless network, video traffic QoS ensures, it mainly comprises: underlay network device, the service application layer of SDN controller and top layer, wherein, underlay network device supports OpenFlow agreement, the underlay network device of described wireless network passes through convergence switch, core route is connected with Internet, Internet is connected with the service switch of support OpenFlow agreement, described underlay network device has installed OpenWrt+OVS system by each wireless access points AP, described SDN controller is managed concentratedly accessing wirelessly access group APs.

Further, described SDN controller comprises device management module, channel-monitoring module, channel adjustment module, regulator module, policy distribution module; Described device management module, for following the tracks of main frame position in a network, supports MAC Address and switch ports themselves, the conversion of MAC Address and IP address, and these information is preserved in a database, when going offline when there being equipment or unload, controller can more new database; Channel-monitoring module, for monitoring AP and intercepting the information of the neighbor AP on each channel; Channel adjustment module, the neighbor information for each AP obtained channel-monitoring module gathers, and draws the optimal wireless channel of each AP by channel adjustment strategy, then issues the message of renewal channel to each AP; Regulator module, first can judge whether packet is video flowing, is if so, then this distribution of flows more queue of large bandwidth and priority of Geng Gao; If not, then by the mode of acquiescence, it is processed; Policy distribution module, monitors the Packet_in message that node sends, checks the matching domain in packet, by the judged result of regulator module write stream list item, finally according to forward-path, respective streams table is handed down to corresponding AP.

A video traffic QoS ensuring method in the software definition wireless network of described framework, it comprises the following steps:

101, set up software defined network framework, comprise underlay network device, the service application layer of SDN controller and top layer, wherein, underlay network device supports OpenFlow agreement;

102, by SDN controller, the AP in wireless network is managed concentratedly; AP broadcasts the information of oneself and monitors the information of neighbor AP and upload SDN controller on channel, and these information are gathered the channel allocation of then carrying out the overall situation by SDN controller;

103, on wireless access points AP, implement mark and forwarding strategy, screen stream is preferentially sent and obtains larger bandwidth.

Further, the channel allocation of carrying out the overall situation in step 102 is specially: AP broadcasts self information and the neighbor AP information intercepted on each channel be uploaded to controller on working channel, and these information gather by controller, pass through function wherein, k ≠ i and wherein k ≠ i, P _kjrepresent AP _kat the signal power statistics AP of channel j _ineighbours' number on channel j and neighbor signal power summation, then sort from big to small to neighbours' number of each AP on working channel, sequentially carry out channel adjustment to each AP.

Further, to the mode that each AP carries out channel adjustment be sequentially: first satisfied wherein represent the mean value be interfered of all AP, then this AP is sorted in the interference of each channel, select the channel that interference is minimum; If draw, least interference channel is not unique, then select the channel that one of them signal power summation is minimum.

Further, step 103 is implemented mark and is specially on wireless access points AP: the Nodes first provided in service carries out DSCP mark to video flowing, then queue q1 and q2 is set respectively on each AP, the band of q1 is wider than the bandwidth of q2, when new packet is through AP, SDN controller determines whether video flowing according to the DSCP value in packet, and if so, in the stream table issued, then setting dequeue is q1 juxtaposition high priority; If not then setting dequeue is q2 juxtaposition low priority.

Advantage of the present invention and beneficial effect as follows:

The network architecture that the present invention is based on software definition builds novel WLAN, and network controller can carry out centralized control to each wireless aps and have the extendible characteristic of programming, effectively can implement qos policy.First the present invention mixed in dividing of wireless channel, by the neighbor information of Real-time Obtaining AP at each channel, then the neighbor information of all AP gathered and draw the optimal wireless channel of each AP, mutually disturbing in same wireless channel of adjacent AP can be avoided.On this basis, the mark that the present invention implements on node and forwarding strategy make screen stream can preferentially send and obtain larger bandwidth thus ensure effective transmission of video flowing, and significant increase user watches the experience of video.

Accompanying drawing explanation

Fig. 1 is the system architecture diagram that the invention provides preferred embodiment;

Fig. 2 is the flow chart of channel adjustment in the present invention.

Embodiment

Below in conjunction with accompanying drawing, the invention will be further described:

The present invention's " in software definition wireless network, video traffic QoS ensures novel architecture and method " specifically comprises the following steps:

Step 1): first build the novel radio LAN backbone based on software defined network.We could carry out centralized control and give alms qos policy based on software defined network to bottom wireless device like this.

Step 2): within cycle time, each AP sends the beacon frame of self information successively to its working channel, and obtain the existence of neighbor AP and the transmitted power of neighbor AP on each channel, finally these information are sent to controller by OpenFlow agreement.

Step 3): the neighbor information of controller to each AP obtained from step 2 gathers goes forward side by side line ordering analysis and then draws the wireless channel of the most applicable AP, then issue upgrade channel message to AP.

Step 4): the channel disturbance that adjacent AP can be avoided after above step completes, on this basis, also differentiated treatment to be carried out at Nodes to video stream traffic and other business.First-selection is marked video flowing by the Egress node place of controller implementation strategy at video service provider, the flow of this mark preferentially sent in the outlet of each access AP and distributes more bandwidth, the forwarding that other flow only carries out FIFO (first-in first-out) by the form of acquiescence and does one's best.

Be illustrated in figure 1 system architecture diagram of the present invention.This framework is the specific implementation of software defined network framework.Primarily of three part compositions: underlay network device, SDN controller, the service application of top layer.Wherein, underlay network device needs to support OpenFlow agreement, the convergence switch of wireless network and the service switch of service provider are the switch supporting OpenFlow agreement, each wireless aps has installed OpenWrt+OVS system, this system is a virtual route system based on linux kernel, supports OpenFlow agreement.First can inquire about self stream table when there being user by AP during AP request msg and whether can mate this packet, if can mate, perform the operation of stream list item; If can not mate, then this packet is sent to SDN controller in the mode of Packet_in message, transfer to the process of SDN controller.SDN controller is as the core of this framework, which replace the AC in conventional WLAN, managed concentratedly APs by it, SDN controller is by issuing Status_Request message to the information of AP inquiry AP, and AP replys controller in the mode of Status_Reply message.Compare traditional AC, SDN controller has the characteristic of expansion able to programme and opening API, and it provides southbound interface and OpenFlow agreement to communicate with underlying device downwards, and distributing policy is to underlying device; Upwards providing northbound interface and API (application programming interfaces) to call for upper-layer service application and development, is also core work place of the present invention to the exploitation of SDN controller, employing be SDN controller be the Floodlight controller of increasing income.Next be that the major function of modules is set forth:

1) equipment control: equipment and control device is connected by TCP Handshake Protocol, this module tracks main frame position in a network, support MAC Address and switch ports themselves, the conversion of MAC Address and IP address, and these information is preserved in a database, when going offline when there being equipment or unload, controller can more new database.

2) channel-monitoring: this module issuing message within cycle time gives each AP, AP is sent to its working channel and carries self information (MAC/IP address, signal power) beacon frame and intercept the information of the neighbor AP on each channel, finally these information are uploaded to channel-monitoring module.

3) channel adjustment: the neighbor information of this module to each AP that channel-monitoring module obtains gathers, and draws the optimal wireless channel of each AP by channel adjustment strategy, then issues the message of renewal channel to each AP.

4) if so, regulator: first this module can determine whether video flowing according to the DSCP value of the packet in Packet_in message is then this distribution of flows more queue of large bandwidth and priority of Geng Gao; If not, then by the mode of acquiescence, it is processed.

5) policy distribution: monitor the Packet_in message that node sends, check the matching domain in packet, by the judged result of regulator module write stream list item, is finally handed down to corresponding AP according to forward-path by respective streams table.

2. channel adjustment strategy

According to the regulation of IEEE802.11 agreement, WLAN (wireless local area network) is operated in the frequency range of 2.4GHz and 5GHz, the frequency range of 2.4GHz has 13 wireless channels can use, but have overlapped between channel, three channels 1,6,11 are wherein only had to be separate nonoverlapping.The wireless channel that this strategy distributes for AP is selected exactly between these three channels, and suppose total M AP, wherein i-th AP is AP _i.This implementation of strategies step:

1) controller gives each AP by channel-monitoring module issuing message, and make AP to the beacon frame of the working channel broadcast self information of oneself, these information comprise oneself MAC/IP address and signal power P _ij, then intercept the information of the neighbor AP of each channel (channel 1,6,11), and these information be uploaded to controller.Controller will draw an overall AP neighbor information table.

2) AP is supposed _ineighbours' number that channel j (j=1,6,11) listens to is X _ij, neighbor signal power summation is Y _ij, wherein neighbours' number represents AP _iin the interference of this channel by how many AP, neighbor signal power summation represents AP _ibe subject to the size of all neighbor AP annoyance levels.

$X_{ij}=\underset{k=1}{\overset{M}{\Σ}}{w}_{kj}$ Wherein,

$Y_{ij}=\underset{k=1}{\overset{M}{\Σ}}{P}_{kj}$ Wherein k ≠ i (2)

Two formulas have added up AP respectively above _ineighbours' number and neighbor signal power and, wherein w _kjrepresent AP _iwhether on channel j, listen to AP _k.

3) to each AP _ineighbours' number X on working channel j _ijsort from big to small, carry out channel adjustment successively according to this order, need meet the following conditions the AP of channel adjustment:

$X_{ij}>=\stackrel{\‾}{X}$ Wherein, $\stackrel{\‾}{X}=\frac{\underset{i=1}{\overset{M}{\Σ}}{X}_{ij}}{M}---\left(3\right)$

(3) represent the mean value that all AP are interfered, work as AP _iworking channel j is interfered X _ijwhen being greater than mean value, illustrating that it is interfered comparatively large, need to carry out channel adjustment, otherwise, channel adjustment is not carried out to it.

The mode of channel adjustment is: first to AP _iat the interference X of each channel j (j=1,6,11) _ijsort, select and wherein disturb minimum channel; If draw, least interference is not unique, then to neighbor signal power and the Y of channel _ijcompare, choose the channel that Y value is minimum.To AP _iadjustment complete after, channel adjustment module will upgrade the overall situation AP neighbor information table, continue to adjust next AP.

3. regulator strategy

Above strategy achieves the reasonable distribution of wireless channel, avoids video flowing congested when channel.As shown in Figure 1, be that a typical Video service provides the network topological diagram accessed with user.In order to promote the Consumer's Experience of Video service, except solving the problem passing channel congestion, the problem of Video service and other service congestion also to be solved at key node place.

Qos policy of the present invention is that class-based mode realizes, according to the flow process of classification-mark-strategy-output queue.Key words sorting realizes according to the mode of mark DSCP (differentiated services code points), and DSCP is the QoS criteria for classification of the differential service (DifferentiatedService) that IETF issues.DSCP is in the service type TOS identification byte of each packet IP head, can be distinguished the priority of different service by mark DSCP value.DSCP value has two kinds of expression waies, digital form and keyword forms.DSCP uses 6 bits, and decimal system interval is 0 ~ 63, can define 64 grade (priority.) as binary system DSCP value 000000=decimal system DSCP value 0, binary system DSCP value 010010=decimal system DSCP value 18.The DSCP value of another kind of keyword form is called per hop behavior (PHB), has the defined PHB of three classes at present, is the service of doing one's best (BE or DSCP0) respectively, guarantees to forward (AF) and expedited forwarding (EF).In diffserv standard, the recommendation DSCP value of video flowing is binary one 00000, and the value of keyword form is CS4.OpenFlow agreement supports DSCP mark mode, and add dscp field at matching domain.Under default situations, the DSCP value of packet is 0, is namely all forward according to the mode of doing one's best when data arrive AP, the performing step of this strategy:

1) labeled bracketing: as shown in Figure 1, video server (IP:10.0.0.1) connected node S1.At this Nodes, mark video flowing, the RestAPI calling controller sends Flow_Mod message and adds stream list item to node S1: be that the DSCP value of the packet of 10.0.0.1 is set as CS4 by IP address; Then also gate region to be added at each AP place, because controller cannot directly be configured underlying device, this is also one of limitation of current OpenFlow agreement, so add queue q1 and q2 by the mode of control desk or OF-Config on each AP, controller is that packet selects queue by sending the mode of Flow_Mod message.When adding queue, should arrange maximum bandwidth and the minimum bandwidth of each queue, this will set according to the maximum bandwidth of each AP, and here, the maximum bandwidth of q1 and q2 adds up to the maximum bandwidth of link, and bandwidth ratio shared by them is respectively 80% and 20%.

2) output queue: when there being new packet by AP, first AP can check the stream list item in stream table, the stream list item that can mate if do not have, this packet is sent to controller process in the mode of Packet_in message, this Time Controller can call the DSCP value that regulator module checks packet, if CS4, then in the stream list item issued, arranging its dequeue is q1, and arranges high priority for this stream list item; If its DSCP value is not CS4, then queue is set and is q2 and for low priority.AP is when forwarding data bag, and can mate successively according to the priority sequence of stream list item, the stream list item that priority is higher more first mates.So just can avoid video flowing arrive AP time and other business produce congested problem.

The present invention is based on software defined network framework, propose one in a wireless local area network for the solution that video flowing QoS ensures, by to AP on each channel intercepting of neighbor information draw an overall AP neighbor information table, judge that current AP is the need of carrying out channel adjustment, if desired adjusting, is that it selects the channel of relative free according to the busy extent of each channel, ensure the reasonable distribution of channel, to meet effective enforcement of the QoS of video flowing; At Nodes, the place of proposing carries out marking for video and other services and the queue mechanism of priority division, can effectively avoid video and other serve produce congested, and the bandwidth safeguard that acquisition is larger.Comprehensive, effectively improve the service quality of user.

These embodiments are interpreted as only being not used in for illustration of the present invention limiting the scope of the invention above.After the content of reading record of the present invention, technical staff can make various changes or modifications the present invention, and these equivalence changes and modification fall into the scope of the claims in the present invention equally.

Claims (6)

1. the novel framework that in a software definition wireless network, video traffic QoS ensures, it is characterized in that, mainly comprise: underlay network device, the service application layer of SDN controller and top layer, wherein, underlay network device supports OpenFlow agreement, the underlay network device of described wireless network passes through convergence switch, core route is connected with Internet, Internet is connected with the service switch of support OpenFlow agreement, described underlay network device has installed OpenWrt+OVS system by each wireless access points AP, described SDN controller is managed concentratedly accessing wirelessly access group APs.

2. the novel framework that in software definition wireless network according to claim 1, video traffic QoS ensures, it is characterized in that, described SDN controller comprises device management module, channel-monitoring module, channel adjustment module, regulator module, policy distribution module; Described device management module, for following the tracks of main frame position in a network, supports MAC Address and switch ports themselves, the conversion of MAC Address and IP address, and these information is preserved in a database, when going offline when there being equipment or unload, controller can more new database; Channel-monitoring module, for monitoring AP and intercepting the information of the neighbor AP on each channel; Channel adjustment module, the neighbor information for each AP obtained channel-monitoring module gathers, and draws the optimal wireless channel of each AP by channel adjustment strategy, then issues the message of renewal channel to each AP; Regulator module, first can judge whether packet is video flowing, is if so, then this distribution of flows more queue of large bandwidth and priority of Geng Gao; If not, then by the mode of acquiescence, it is processed; Policy distribution module, monitors the Packet_in message that node sends, checks the matching domain in packet, by the judged result of regulator module write stream list item, finally according to forward-path, respective streams table is handed down to corresponding AP.

3., based on a video traffic QoS ensuring method in the software definition wireless network of framework described in claim 1, it is characterized in that, comprise the following steps:

101, set up software defined network framework, comprise underlay network device, the service application layer of SDN controller and top layer, wherein, underlay network device supports OpenFlow agreement;

102, by SDN controller, the AP in wireless network is managed concentratedly; AP broadcasts the information of oneself and monitors the information of neighbor AP and upload SDN controller on channel, and these information are gathered the channel allocation of then carrying out the overall situation by SDN controller;

103, on wireless access points AP, implement mark and forwarding strategy, screen stream is preferentially sent and obtains larger bandwidth.

4. video traffic QoS ensuring method in software definition wireless network according to claim 3, it is characterized in that, the channel allocation of carrying out the overall situation in step 102 is specially: AP broadcasts self information and the neighbor AP information intercepted on each channel be uploaded to controller on working channel, these information gather by controller, pass through function wherein, k ≠ i and wherein k ≠ i, P _kjrepresent AP _kin the signal power of channel j, statistics AP _ineighbours' number on channel j and neighbor signal power summation, then sort from big to small to neighbours' number of each AP on working channel, sequentially carry out channel adjustment to each AP.

5. video traffic QoS ensuring method in software definition wireless network according to claim 4, is characterized in that, to the mode that each AP carries out channel adjustment is sequentially: first satisfied wherein represent the mean value be interfered of all AP, then this AP is sorted in the interference of each channel, select the channel that interference is minimum; If draw, least interference channel is not unique, then select the channel that one of them signal power summation is minimum.

6. video traffic QoS ensuring method in software definition wireless network according to claim 4, it is characterized in that, step 103 is implemented mark and is specially on wireless access points AP: the Nodes first provided in service carries out DSCP mark to video flowing, then queue q1 and q2 is set respectively on each AP, the band of q1 is wider than the bandwidth of q2, when new packet is through AP, SDN controller determines whether video flowing according to the DSCP value in packet, if so, in the stream table issued, then setting dequeue is q1 juxtaposition high priority; If not then setting dequeue is q2 juxtaposition low priority.