CN103457999B - A kind of P2P document transmission method based on the NDN network architecture - Google Patents

Abstract

The application discloses a kind of P2P document transmission method based on the NDN network architecture, after reaching the standard grade, active user can safeguard exactly its online user's list, and obtain by send searching request bag in NDN network the search result data bag that object user returns, thereby obtain the details of file destination, active user obtains by send download request bag in NDN network the downloading data bag that object user returns, thereby obtain the piecemeal of file destination, the piecemeal splicing of file destination is obtained complete file destination by active user afterwards, thereby realize the stable transfer of P2P file in NDN network.

Description

A kind of P2P document transmission method based on the NDN network architecture

Technical field

The application relates to network communication field, is specifically related to a kind of P2P file transfer side based on NDN networkMethod.

Background technology

P2P(Peer-to-Peer) network is the nerve of a covering being structured on IP network, in P2P network,Each main frame is client, is also server, and each main frame is all contributed a part of system of oneselfResource, such as file, bandwidth, peripheral hardware etc. come for other host services in same P2P network. P2P netOne of main purposes of network is to carry out file-sharing, and it allows between any terminal use's peer-to-peer (Peer) straightConnect internet and completed exchange files, do not need to revise the fabric of already present software protocol and networkJust can add rapidly new network function.

But, the following problem of P2P application ubiquity under the TCP/IP network architecture at present:

(1) existing P2P shared file system is not complete decentralization.

In fact, in P2P pattern, might not be also completely acentric, it can be divided into pure P2P andMixed P 2 P two classes. Pure P2P pattern refers to that the computer of all participations is all reciprocity point, each reciprocity pointBetween Direct Communication, do not have completely from start to finish central server to the information exchange between equity point control,Coordinate or process. Mixed P 2 P pattern depends on central server and goes operating part function.

P2P document exchange system has following several different form at present. One be " hub file catalogue/pointCloth formula file system ", when its swap data, carry out directory management by central server. Due to employing, so inevitably there is the problem of "bottleneck" in centralized directory management. An other class belongs to completelyP2P, this type systematic does not have intermediate server, closer to absolute freedom, because there is no intermediate server,The P2P network forming is like this difficult to carry out controls such as safety management, authentication, traffic management, chargingSystem. The 3rd type systematic is the compromise of upper two type systematics---have intermediate server, but file directory distributes.

(2) penetration problem of network address translation (NAT, NetworkAddressTranslation) is P2PTechnical development one of the subject matter that must solve.

While online by NAT, can only initiatively initiate connection request to outside main frame by the main frame in NAT,Forbid that external host initiatively connects with NAT internal host. For adopting downloading of P2P modeSpeech, because the main frame in NAT can not receive the connection of NAT outside, thereby causes linking number very few, underThe speed of carrying is slow. Therefore P2P software must solve the problem that the internal host of NAT can not be connected by outside.

(3) existing P2P shared file system is still faced with the excessive problem of central server load.

Because some function in the P2P shared file system under the current TCP/IP network architecture still needs central authoritiesThe support of server, such as BT(BitTorrent) in tracker(central directory server), day netClient server and heartbeat server etc. in Maze. When in system, occur that a large amount of nodes add dynamically or fromWhile opening, bring very large load can to these central servers. In addition, utilize central server to be responsible for catalogueThe service of management is because be subject to the restriction of server, and presence service quality cannot improve the problem with single-point collapse.

(4), in existing P2P shared file system, the implementation method of download function is not very accurate nearby.

In P2P network, euclidean distance between node pair is often studied problem. From literal, distance has representedRelativeness spatially between node, the relatively near node of distance can be called mutually " neighbours ". TCP/IPAgreement take position as fundamental, and IP address represents the positional information of node, so determining for " distance "Justice is very directly perceived. In existing P2P shared file system, the general principle that distance is calculated is according to userDivide into groups as prefix in the front X position (for example first 16) of IP. Although this method is simple to operate, itsThe degree of accuracy is not high.

(5) great advantage of existing P2P file-sharing application is to make full use of Internet resources, but the effect of downloadRate is not very desirable, not high to the utilization rate of the network bandwidth yet.

Although existing P2P file-sharing application takes full advantage of the computer of individual subscriber and uploads, downloadsSpeed, has shared the pressure of server, but the network facilities has been had higher requirement simultaneously, to Netowrk tapeWide occupancy is very big and utilization rate is not high, sometimes even can cause network congestion phenomenon, and is not easy to search,Download also unstable.

NDN network is introduced:

The core concept of current widely used computer network transfer protocols (ICP/IP protocol) is in previous generationSix the seventies of recording put forward, and computer network was mainly designed to solve resource-sharing problem at that time,Such as long-range use supercomputer etc., thereby what design is the logical of a kind of point-to-point (Point-to-Point)Letter model, normally a side proposes to use resource, and the opposing party provides mandate. But semicentennial in processAfter development, computer hardware equipment becomes and is dirt cheap, simultaneously the development speed of whole internet out ofPeople's the imagination, the data content in network is constantly blast trend growth. People also shift emphasis graduallyTo the data content of wanting to obtain, and be no longer to share to use remote hardware resource. But, network serviceModel is but still in the design concept of continuing to use eighties of last century six the seventies, if obtain data, and first necessaryKnow the IP address information of data place main frame, and connect and transmit needed number by setting up end to endAccording to. This design has brought a lot of problems to the transmission of data, such as the safety problem of data channel, networkCongestion problems, the disconnection in WIFI transmission with reconnect problem etc. Under this background, taking data content asThe named data network transport mechanism (NamedDataNetworking, NDN) of core is arisen at the historic moment.

NDN is also called Content-CentricNetworking (CCN), is to be ground by the PARC of famous AmericanStudy carefully in 2006 initiate about Future Internet architecture, i.e. FIA(FutureInternetArchitecture) project of research, participant comprises ten Yu Suo university and research institutes of the U.S.. This project is 2010Obtain the subsidy of American National nature fund (NSF) year. The leader of NDN project mainly contains UCLALixia ZHANG professor and the VanJacobson of PARC research institute, wherein Jacobson is to have invented TCP/IPCongestion control algorithm and well-known, the object that he proposes NDN agreement exists in order to solve under TCP/IP framework justProblems. VanJacobson points out, in today of internet data blast, when people use internetPay close attention to the content (What) comprising in network, and communication mode remains position-based (Where),This inconsistent problem such as validity and security of having brought, solution is introduced named data exactly(NamedData), with " what is " replacement " where ". NDN agreement is implemented in this name exactlyOn the basis of data.

NDN project is intended to develop a new Internet architecture, makes full use of current Host Based point rightPut the advantage of the Internet architecture of communication, and solve the deficiency of current network framework, emerging naturally to adapt toInternet communication pattern. By numerical nomenclature, instead of position name, NDN becomes data mainEntity. NDN protocol frame, taking the data propagated as core element, relies on the information exchange of data itself to cross structureBuild and rationally effectively named transfer of data, and no longer need the physical location of focused data, this spyPoint meets the mode of operation of most of data driven applications in current internet more. Current internet ensuresThe safety of data capsule (main frame), and NDN ensures the safety of content, such design by credible data andMain frame is credible to be separated, and makes some highly extendible communication mechanisms become possibility, for example, by automatically slowDeposit to optimize bandwidth.

NDN, for the current existing procotol of compatibility, has adopted establishing of a kind of " universaloverlay "Meter. That is to say that NDN may operate on any network in theory, certainly also comprise traditional TCP/IPNetwork. CCNx engineering is the one that carries out NDN theory in the CSL laboratory of the PARC Project Realization of increasing income,Whole engineering is implemented on conventional TCP/IP network, has realized the Interest/Data communication equipment in NDNSystem.

Summary of the invention

The application provides a kind of P2P document transmission method based on NDN network, can realize the net at NDNThe stable transfer of P2P file in network.

Be somebody's turn to do the P2P document transmission method based on the NDN network architecture, comprise:

Active user creates empty online user's list, calculates and plucks according to this sky online user listBe worth, and send synchronization request bag in NDN network, described synchronization request handbag is drawn together sky online user listDigest value.

If active user does not get other online user and returns according to described synchronization request bag in Preset TimeReturn synchronization packets time, active user will self join in online user's list, and upgrades current onlineThe digest value of user list; If getting other user in Preset Time, active user synchronously please according to describedAsk while wrapping the synchronization packets of returning, active user upgrades active user's online use according to this synchronization packetsFamily list and digest value thereof, afterwards, active user joins self in online user's list again, and upgradesThe digest value of current online user list.

Active user sends searching request bag in NDN network, and described searching request handbag is drawn together object user letterBreath, active user obtains the search result data bag that object user returns according to described searching request bag afterwards,Described search result data handbag is drawn together the information of the file destination of active user's search.

Active user according to the information of described file destination to sending in NDN network for downloading object fileDownload request bag, and obtain and there is the download that the online user of file destination returns according to described download request bagPacket, described downloading data handbag is drawn together the piecemeal of file destination, and afterwards, active user is by file destinationPiecemeal splicing obtains complete file destination.

The P2P document transmission method based on the NDN network architecture that the application provides, after active user reaches the standard grade isCan safeguard exactly its online user's list, and realize the stable transfer of P2P file in NDN network.

Brief description of the drawings

Fig. 1 is the name form schematic diagram of request bag in a kind of embodiment of the application;

Fig. 2 is that in a kind of embodiment of the application, the P2P document transmission method flow process based on the NDN network architecture is shownIntention;

Fig. 3 is the method flow schematic diagram of user's discovery mechanism in a kind of embodiment of the application;

Fig. 4 is the basic process schematic diagram of file destination transmission in a kind of embodiment of the application;

Fig. 5 is while adopting the P2P document transmission method based on the NDN network architecture in a kind of embodiment of the applicationAverage transmission round trip delay time schematic diagram;

Fig. 6 is while adopting the P2P document transmission method based on the NDN network architecture in a kind of embodiment of the applicationAverage speed of download schematic diagram;

Fig. 7 is while adopting the P2P document transmission method based on the NDN network architecture in a kind of embodiment of the applicationOffered load schematic diagram.

Detailed description of the invention

NDN agreement: NamedDataNetworking, the named data network transmission protocol, NDN is also calledContent-CentricNetworking (CCN), NDN protocol frame is taking the data propagated in network as core unitElement, the information exchange of dependence data itself is crossed to build and has rationally effectively been named transfer of data, and no longer needsWant the physical location of focused data. Corresponding, the network that uses NDN agreement to carry out transfer of data is called NDNNetwork.

Because NDN protocol frame is taking the data propagated as the feature of core element and " receiving terminal driving "Design philosophy and P2P file transmitting function have natural similitude, so by NDN agreement and P2P fileTransmission is in conjunction with just becoming a kind of possibility. In the embodiment of the present application, NDN protocol application is passed to P2P fileIn defeated, be intended to solve existing P2P file transfer above-mentioned remain several subject matters.

The correlative study of NDN agreement at present mainly contains two kinds of thinkings: one is real by theory analysis and simulationThe method of checking, inquires into the detail that agreement realizes, comprise how realizing the inquiry of quick routing table, asWhat selects buffer memory and replacement policy, exchanging routing information etc. how, also considers the following extensive portion of agreement simultaneouslyExtensibility in administration's situation, with the compatibility of existing network protocol, and how by current interconnected rackStructure smooth transition is to the problem of the NDN network architecture; Another kind is answering based on NDN agreement by exploitationWith, verify the feasibility of NDN agreement and the reasonability of design, from the process of application and development, obtainFeedback, carrys out further Improvement and perfection NDN agreement, and is that other application based on NDN agreement is opened in the futureSend out and accumulate experience.

But, not yet have any disclosed or generally acknowledged P2P file transfer side based on NDN network at presentMethod. In the embodiment of the present application, based on the existing Project Realization CCNx Open Source Code of NDN agreement, by rightIn NDN agreement one of the function realizing method such as user's discovery mechanism, neighbours' mechanism, file search and downloadSeries Design, has represented a kind of P2P document transmission method based on NDN network.

For the convenient understanding to the application, in the embodiment of the present application mainly with sky net Maze shared file systemFor example, the P2P document transmission method based on the NDN network architecture that the application is provided describes.

In order to realize better the P2P file transfer based on NDN network, first the embodiment of the present application providesA kind of NDN protocol infrastructure nomenclature principle, it adopts has hierarchically structured variable-length identifier(HSVLI) as naming rule.

The name form of the request bag based in NDN network is divided into two kinds below:

1) specify object user: ccnx :/<APPName>/uni/<UserID>/<function_parameters>.

2) do not specify object user (the request bag of for example broadcast type):

ccnx:/<APPName>/multi/<function_parameters>。

Wherein, ccnx :/be NDN protocol-identifier,<APPName>be application identities, uni and multi are used forDistinguish the type (specify object user or do not specify object user) of request bag,<function_parameters>It is the parameter value that need to arrange for the realization of specific function.

Taking sky net Maze shared file system as example, the name form of its request bag as shown in Figure 1, wherein,Namespace is a day server network address for net Maze shared file system; ApplicationName isNdnmaze; Destination refers to the object user profile that this request bag mails to, if this request bag is for specifying orderUser type time, adopt uni to identify, if this request bag is not when specifying object user type,Adopt multi to identify; Function_Parameters has comprised the functional parameter value that this request bag carries.

By reference to the accompanying drawings the application is described in further detail below by detailed description of the invention.

Please refer to Fig. 2, the present embodiment provides a kind of P2P document transmission method based on the NDN network architecture,Comprise:

Step 1.1: active user sends synchronization request bag to other online user. After active user reaches the standard grade, whenFront user creates empty online user's list, calculates digest value according to this sky online user list,And sending synchronization request bag in NDN network, this synchronization request handbag is drawn together the summary of sky online user listValue.

Step 1.2: return according to synchronization request bag if active user does not get other user in Preset TimeReturn synchronization packets time, active user will self join in online user's list, and upgrades current onlineThe digest value of user list; If active user gets other user according to synchronization request bag in Preset TimeReturn synchronization packets time, active user upgrades online user's row of active user according to this synchronization packetsTable and digest value thereof, afterwards, active user joins self in online user's list again, and upgrades currentThe digest value of online user's list.

Step 1.3: active user sends searching request bag in NDN network, and searching request handbag is drawn together objectUser profile.

Step 1.4: active user obtains the search result data bag that object user returns according to searching request bag,Search result data handbag is drawn together the information of the file destination of active user's search.

Step 1.5: active user according to the information of file destination to sending and be used for downloading target in NDN networkThe download request bag of file.

Step 1.6: active user obtain have that the online user of file destination returns according to download request bag underCarry packet, downloading data handbag is drawn together the piecemeal of file destination, and afterwards, active user divides file destinationPiece splicing obtains complete file destination.

In the present embodiment, active user upgrades the online user's list of self at every turn and when digest value, also willWhen renewal, user's change information is recorded in Update log. Accordingly, synchronization packets comprises synchronization requestThe summary of online user's list of the user of the digest value of online user's list and this synchronization packets of transmission in bagUser's change information between value; Active user upgrades active user's online user according to this synchronization packetsList and digest value thereof, for active user upgrades current use according to the change information of user in this synchronization packetsOnline user's list and the digest value thereof at family.

In step 1.2, if active user receives other online user's synchronization request in Preset TimeBag, is buffered in this synchronization request bag in list to be replied, and has upgraded the online use of self active userAfter family list and digest value thereof, then this synchronization request bag is replied.

Step 1.1 and step 1.2 are the P2P file transfer of the embodiment of the present application based on the NDN network architectureUser's discovery mechanism in method, please refer to Fig. 2, is its concrete grammar flow chart, comprising:

Step 101: need to create empty online user's list after active user reaches the standard grade, and exist according to this skyLine user list calculates digest value, and this digest value is as the functional parameter value of synchronization request bag, now,Digest value is also empty, and in an instantiation, digest value can be MD5 value.

Step 102: active user sends synchronization request bag in NDN network.

Step 103: whether active user gets other online user according to this synchronization request in Preset TimeThe synchronization packets that bag returns, if so, forwards step 104 to, if not, forwards step 105 to.

It should be noted that, active user, in this section of Preset Time, also can receive that other online user's is sameStep request bag, now the synchronization request bag of receiving is kept at local PIT(pendinginterest by active userTable, waits for the request the package list of replying) inner.

Step 104: if active user has got the synchrodata that other online user returns in Preset TimeBag,, according to online user's list and the digest value thereof of this synchronization packets renewal self, forwards step to afterwards againRapid 105.

Step 105: if active user does not get the same step number that other online user returns in Preset TimeAccording to bag, illustrate that active user is the unique online user in system, directly execution step from step 103105, otherwise in the rear execution step 105 of execution of step 104. Now active user joins self onlineIn user list, and upgrade its digest value.

Step 106: active user is recorded to the user's of this renewal change information in Update log, currentUser, as long as online user's list and digest value thereof are upgraded, needs the user's of this renewalChange information is recorded in Update log.

Step 107: whether active user inquires about to exist in local PIT needs that other online user's of replying is sameStep request bag, if so, forwards step 108 to, if not, forwards step 102 to.

Step 108: extract the digest value in this synchronization request bag.

Step 109: judge that whether the digest value carrying in synchronization request bag is identical with active user's digest value,If so, forward step 110 to, if not, forward step 111 to.

Step 110: if the digest value carrying in synchronization packets is identical with active user's digest value, willThis synchronization packets abandons.

Step 111: active user is by user between digest value in self digest value and synchronization request bag to be repliedChange information be packaged as synchronization packets, reply to corresponding online user.

Should be appreciated that each online user needs to safeguard online user's list, and online according to thisUser list calculates digest value, and the user online user list of newly reaching the standard grade is for empty, and digest value is also empty.And all online users need regularly to send synchronization request bag and carry out the synchronous of information, as step 102,Shown in step 111, after current step, all forward step 102 to executing. Same by exchange between online userStep request bag and synchronization packets complete the synchronizing process of online user's information, whenever online user's list has changeWhen change, user needs according to new online user's list update digest value, and ought in time renewal process, useThe change information at family is recorded in Update log (TransactionLog).

In an instantiation, the form of synchronization request bag is as follows:

ccnx:/maze.tianwang.com/ndnmaze/multi/<digest_value>/

Because the send mode of synchronization request bag is broadcast type, so, multi conduct in synchronization request bag, usedThe mark of send mode, wherein<digest_value>be that user calculates according to online user's list of self maintainedThe digest value obtaining.

Through above process, just complete the process of synchronizing information between all online users, also just realizeUser's function of reaching the standard grade. And utilize the P2P file based on the NDN network architecture that the present embodiment provides to passTransmission method, carries out information when synchronous online user, simpler compared with existing P2P document transmission methodSingle, and belong to complete decentralization, save this important central server of heartbeat server.

In the present embodiment, preferred, active user has upgraded after the online user's list and digest value thereof of self,Send before searching request bag to online user, also comprise:

Active user calculates self and other online user's distance, and this distance is recorded in to online user's rowIn table; When active user sends searching request bag to online user, active user is online according to self and otherUser's distance, from closely to sending far successively searching request bag. Distance between user is recorded in to online useCan be by mode below in the list of family: in online user's list of each user, added one " latency "Field is for the distance between recording user.

Active user can come and go and prolongs by calculating number of nodes between self and other online user or transmissionLate the time is calculated self and other online user's distance, the joint between active user and other online userPoint quantity is more or transmission round trip delay time is longer, is designated as active user and this online user's distance moreFar, on the contrary the distance that is designated as active user and this online user is nearer.

In an instantiation, can pass through method below and calculate between active user and other online userTransmission round trip delay time.

1) each online user is maintaining online user's list, and active user is by giving successively online usingUser in the list of family sends a request bag and initiates round-trip delay measurement, and the form of request bag is as follows:

ccnx:/maze.tianwang.com/ndnmaze/uni/<req_measure_latency>/UserID/<timestamp>。

What User_ID field represented is the ID that receives this request bag, and what timestamp field represented is to send outThe current time of active user's the machine while giving this request bag.

2) object user receives after this this request bag, replys an empty packet, the timestamp of this packetField is not made any amendment to the timestamp of request bag and is directly returned.

3) active user receives after packet, extracts the value of timestamp field, then will receive dataPoor (the transmitting round trip delay time) of the machine time when bag and the value of timestamp field as node itBetween distance measured value preserve.

Online user, can be according to the order from the near to the remote of distance between user in the time safeguarding online user listSort, thereby realize the use in the P2P document transmission method based on NDN network that the present embodiment providesFamily neighbours' mechanism.

In step 1.3 and step 1.4, when each online user is safeguarding that has been realized neighbours' machineSystem online user's list time. Active user can carry out file search by two kinds of modes below:

1) in one embodiment, searching request bag also comprises object user's share directory mark, target literary compositionThe information of part comprises the directory content under share directory mark. This file search method is for to find by userFile: from online user's list, select a user, send searching request bag in NDN network, andBe transferred to object user by NDN network according to the object user profile of carrying in searching request bag, thereby obtainObtain the directory content under object user share directory mark. Now, the form of searching request bag is as follows:

ccnx:/maze.tianwang.com/ndnmaze/uni/UserID/<share_root>/

Wherein, because searching request bag sends to single object user, therefore, in searching request bag, makeMark with uni as send mode, UserID is object ID,<share_root>be object userShare directory mark.

By that analogy, by change in searching request bag<share_root>value, just can check respectively sameObject user's directory contents at different levels, then therefrom select interested file destination to download by user.

Now, in the process of search file destination, can be according between active user and other online userDistance, first checked the online user of near distance by user, from closely to far away until search file destination, canTo reduce the time of file destination transmission (download).

2) in another embodiment, searching request bag also comprises the searched key word of file destination, file destinationInformation mate with searched key word. This file search method is for passing through " mass-sending " mode search file:Be that first active user arranges a higher limit to return data, then according to distance from closely to far successively toUser in line user list sends searching request bag. Now, the form of searching request bag is as follows:

ccnx:/maze.tianwang.com/ndnmaze/uni/<UserID>/<keyword_search>/

Wherein,<keyword_search>for user set searched key word. After search finishes, returnBe the information of mating with this searched key word to the information of active user's file destination.

The informational needs of the file destination returning obtaining when active user searches for file destination comprises file destinationThe information such as filename, file type, file size, in an instantiation, the information of file destination isUse XML organising data information, its format fragment is as follows:

<Filescount=”2”>

<File>

<name>The beautiful .pdf of programming</Name>

<type>File</Type>

<Size>12345678</Size>

<Digest>xxxxxxxx</Digest>

</File>

<File>

<Name>C++</Name>

<type>Catalogue</Type>

</File>

</Files>

Active user, as a client, need to be searched for the result presentation of file destination to user, because ofThis, when each Search Results is successively after multiple users return, due to the search knot obtaining from each userFruit is also XML form, and the information of these file destinations is merged, arranged, then with user-friendlyMode is presented on client end interface.

In an instantiation, the online user who receives searching request bag can be slow by the result of search at every turnDeposit certain hour, so that process the situation that identical searching request bag arrives again. Receiving identical searchingWhen rope request bag, just can directly return results, the result of buffer memory adopts LRU(LeastRecentlyUsed nearMinimum use algorithm of phase) strategy replaces.

In the present embodiment, active user according to the information of file destination to sending and be used for downloading order in NDN networkThe download request bag of mark file, comprising: active user is same to having file destination according to the information of file destinationOne or more online user sends the download request bag for downloading object file. Be that active user canBy the transmission of mode realize target file that single-point is downloaded or multiple spot is downloaded.

Carrying out single-point while downloading, get after the search result data bag that object user returns active user,Send before download request bag, also comprise:

Active user sends the version information request bag for obtaining file destination version information to object user,And obtain the version information packet with file destination version information that object user returns; Download request bagComprise file destination version information.

In the time carrying out file transfer, first active user sends one and does not comprise version information and segment identificationVersion information request bag, version information request is surrounded by two aspect effects, and the one, notice object user is readyTransfer files is to obtain by version information request bag the version information of wanting file destination on the other hand. CurrentUser gets after the version information of file destination, can again send download request bag, and download request includesThe version information of file destination and segment identification.

In the time carrying out multiple spot download, file destination in the search result data bag that active user obtains in step 1.4The prerequisite of information under, to the download request bag that sends the digest value of a based target file in NDN network,Now, the form of download request bag is as follows:

ccnx:/maze.tianwang.com/ndnmaze/multi/<file’s_digest_value>/

Wherein,<file ' s_digest_value>for the digest value of the file destination that returns in step 1.4 is (as above-mentionedDigest field in the format fragment fragment of the information of file destination).

Please refer to Fig. 4, is the basic process of file destination transmission, and in step 4.1, active user is to object userSend download request bag to obtain some piecemeals of file destination, in step 4.2, object user is according to stepDownload request bag in 4.1 returns to the downloading data bag that carries respective objects file block, and step 4.3 is attached most importance toMultiple step 4.1 and step 4.2, until active user has got all points of file destination from object userPiece. Now, active user, by the exchange of a series of download request bag and downloading data bag, gets orderAfter each piecemeal of mark file, the piecemeal splicing of file destination is obtained to complete file destination. Should be appreciated thatSingle online user when object user herein can refer to use single-point to download, also can refer to use under multiple spotMultiple online users while carrying.

It should be noted that, in an instantiation, the file destination size that uses multiple spot to download has been carried outLimit. In order to make multiple spot download mechanism obtain better performance, so not all file destination allNeed multiple spot to download. For example,, if file destination too little (such as being less than 10M) there is no need so completelyUse multiple spot is downloaded, and the more possibilities on the contrary of object user are because the increase of the additional networks traffic cause downThe phenomenon that the speed of carrying declines. Such as in sky net Maze shared file system, small documents quilt in system is a large amount ofShared propagation, so this restriction can improve the file transfer performance of system, be highly significant.

Should be appreciated that when active user sends request bag or packet to online user, only need to be to NDN netIn network, send this request bag or packet, NDN network is again according to pointing in this request bag or packetOnline user is transmitted to corresponding online user.

The existing Project Realization CCNx of the embodiment of the present application based on NDN, realizes NDN by said methodThe transmission of P2P file under network, should can make full use of by the P2P document transmission method based on NDN networkContentStore mechanism in NDN agreement, identical application data is carried out multiplexing, thereby reduce networkThe traffic, reduces and downloads delay, and improve data transmission efficiency.

The P2P document transmission method based on the NDN network architecture that utilizes the present embodiment to provide, online userWhen the information of carrying out is synchronous, simpler compared with existing P2P document transmission method, and in belonging to and going completelyThe heart, save this important central server of heartbeat server. Do not carry out file destination when search also notNeed to rely on central node completely, weak center more on the whole, has reduced the need for server loadAsk, also can reduce because central node fault causes the impact of service failure.

Location independence (Location-Independence) is one of NDN server design philosophy,Also be different from TCP/IP network architecture maximum. In the embodiment of the present application, P2P document transmission method based onNo matter NDN network, be the catalogue of browsing online user, the realization side of the functions such as still search, download fileMethod, its process does not need to pay close attention to the positional informations such as IP address, port again. This characteristic to a great extentReduce the pressure of Network application and development work.

The method that the embodiment of the present application provides can be utilized natural network connectivty under the NDN network architecture, fromAnd the problem that solution Intranet penetrates. The settling mode of NDN agreement is the method for similar relay forwarding, but in factExisting mode is more natural, without realizing complicated processing logic, only needs simple Forward-reques bag and does not needCarry out any amendment, packet returns according to the reverse path of request bag. At NDN net environment,Intranet user will no longer have particularity, and it exists, and with regard to no longer becoming, success rate is downloaded in reduction and search is efficientFactor. In the implementation procedure of P2P file transfer, also a large amount of relevant to network connectivty without processing againThe affair logic, this is for reducing implementation complexity and improving user and experience the place that is all highly profitable.

The embodiment of the present application provides two kinds of modes to define and measure the distance between online user, and then realizesNeighbours' mechanism, for " downloading nearby ". A kind of method is according to the number of nodes between user (or jumping figure),More common number of nodes distance be also far away. Another kind method is the time delay while calculating user interactions. PhaseThan the realization of this mechanism under the current TCP/IP network architecture, the method in the embodiment of the present application is more reliable,More accurate.

In addition, please refer to Fig. 4-7, the method that the embodiment of the present application provides, its average transmission round-trip delay, flatAll the performance performance in speed of download and three indexs of offered load is better than under the existing TCP/IP network architectureP2P document transmission method.

In Fig. 5, the P2P literary composition based on the NDN network architecture of curve 501 for adopting the embodiment of the present application to provideAverage transmission round trip delay time when part transmission method, curve 502 is for adopting traditional TCP/IP network rackAverage transmission round trip delay time when the P2P document transmission method of structure.

In Fig. 6, the P2P literary composition based on the NDN network architecture of curve 601 for adopting the embodiment of the present application to provideAverage speed of download when part transmission method, curve 602 is for adopting the P2P of traditional TCP/IP network architectureAverage speed of download when document transmission method.

In Fig. 7, curve 700 is the offered load under ideal situation (idealcondition), curve 701Network when adopting the P2P document transmission method based on the NDN network architecture that the embodiment of the present application provides is negativeCarry curve 702 offered load when adopting the P2P document transmission method of traditional TCP/IP network architecture.

The existing P2P document transmission method based on the TCP/IP network architecture adopts in order to improve data transmission baudsSet up the mode that multiple TCP connect, and this method causes a large amount of consumption of the network bandwidth simultaneously. AndIn ICP/IP protocol, in the packet due to the transmission of each signal post, transmission user and reception have all been comprised simultaneouslyUser's IP address, this just makes the data that signal post comprises each time only effective for this session. ThereforeIn the time occurring multiple request of same data, same piece of data just has to repeat transmit repeatedly, this feelingsCondition is brought very large burden to central server, has also caused a large amount of bandwidth waste simultaneously.

By contrast, the P2P document transmission method based on the NDN network architecture that the embodiment of the present application provides,In the search and downloading process of file destination, in the name of request bag, do not comprise active user's information,That is to say, when there being multiple user's requests to check same share directory or the same target literary composition of request downloadWhen part, also will send identical request and wrap in NDN network, corresponding, same piece of data bag can be expiredAll identical requests in foot network. This situation take full advantage of NDN agreement to the characteristic of numerical nomenclature andIts content caching and distribution mechanisms, carry out multiplexingly to identical application data, avoided the repetition of identical dataTransmission, has effectively alleviated access pressure and the hot resource of popular user in the time of viewed catalogue and has been downloadedTime the problem such as bandwidth pressure, thereby greatly reduced Internet traffic, reduce average download and postpone, and carryHigh data transmission efficiency.

The all or part of step that it will be understood by those skilled in the art that the whole bag of tricks in above-mentioned embodiment canComplete to carry out instruction related hardware by program, this program can be stored in a computer-readable recording medium,Storage medium can comprise: read-only storage, random access memory, disk or CD etc.

Above content is the further description of the application being done in conjunction with concrete embodiment, can not recognizeThe concrete enforcement of determining the application is confined to these explanations. For the ordinary skill of technical field under the applicationPersonnel, not departing under the prerequisite of the present application design, can also make some simple deductions or replaceChange.

Claims (9)

1. the P2P document transmission method based on the NDN network architecture, is characterized in that, comprising:

Active user creates empty online user's list, calculates and plucks according to this sky online user listBe worth, and send synchronization request bag in NDN network, described synchronization request handbag is drawn together sky online user listDigest value;

If active user does not get other online user and returns according to described synchronization request bag in Preset TimeReturn synchronization packets time, active user will self join in online user's list, and upgrades current onlineThe digest value of user list; If getting other user in Preset Time, active user synchronously please according to describedAsk while wrapping the synchronization packets of returning, active user upgrades active user's online use according to this synchronization packetsFamily list and digest value thereof, afterwards, active user joins self in online user's list again, and upgradesThe digest value of current online user list;

Active user sends searching request bag in NDN network, and described searching request handbag is drawn together object user letterBreath, active user obtains the search result data bag that object user returns according to described searching request bag afterwards,Described search result data handbag is drawn together the information of the file destination of active user's search;

Active user sends for downloading object file in NDN network according to the information of described file destinationDownload request bag, and obtain have that the online user of file destination returns according to described download request bag underCarry packet, described downloading data handbag is drawn together the piecemeal of file destination, and afterwards, active user is by file destinationPiecemeal splicing obtain complete file destination.

2. the method for claim 1, is characterized in that, described searching request bag also comprises objectUser's share directory mark, the information of described file destination comprises in the catalogue under described share directory markHold.

3. the method for claim 1, is characterized in that, described searching request bag also comprises targetThe searched key word of file, the information of described file destination is mated with described searched key word.

4. the method for claim 1, is characterized in that, gets object user active userAfter the search result data bag returning, send before download request bag, also comprise:

Send for obtaining the version information request bag of file destination version information to object user, and obtain orderThe version information packet with file destination version information that returns of user; Described download request handbag is drawn togetherDescribed file destination version information.

5. the method for claim 1, is characterized in that, active user is according to described file destinationInformation to sending the download request bag for downloading object file in NDN network, comprising:

Active user according to the information of described file destination to have file destination same or two above onlineUser sends the download request bag for downloading object file.

6. the method for claim 1, is characterized in that, active user upgrade at every turn selfWhen line user list and digest value thereof, during also by renewal, user's change information is recorded in Update log;

Described synchronization packets comprises the digest value and this same step number of transmission of online user's list in synchronization request bagAccording to the change information of user between the user's of bag the digest value of online user's list;

Described active user upgrades active user's online user's list and summary thereof according to this synchronization packetsValue, for active user is according to the change information renewal active user's of user in this synchronization packets online userList and digest value thereof.

7. the method for claim 1, is characterized in that, active user is in described Preset TimeIf receive other online user's synchronization request bag, this synchronization request bag is buffered in list to be replied,Upgrade active user after the online user's list and digest value thereof of self, then this synchronization request bag has been carried outReply.

8. the method as described in claim 1-7 any one, is characterized in that, active user has upgradedAfter self online user's list and digest value thereof, send before searching request bag to online user, also comprise:

Active user calculates self and other online user's distance, and this distance is recorded in to online user's rowIn table;

When active user sends searching request bag to online user, active user uses online according to self and otherThe distance at family, from closely to sending far successively described searching request bag.

9. method as claimed in claim 8, is characterized in that, active user calculates self and other and existsLine user's distance, comprising:

Active user calculates number of nodes or the transmission round trip delay time between self and other online user,Number of nodes between active user and other online user is more or transmission round trip delay time is longer, noteFor active user and this online user's distance is far away, otherwise, be designated as active user and this online user's distanceClose to more.