CN106603297A - Content provider mobile switching method of content center network - Google Patents

Abstract

A mobile switching method for a content provider in a content-centric network. The content provider records the current service quantity of each content it provides, and sets the switching service threshold according to the actual mobile demand; Whether the current service quantity of a content is not less than the switching service threshold, if so, push the complete sample of the content to the original access router by sending a sample push data packet, so that multiple requesters who request the content can pass The original access router continues to obtain services, ensuring the communication continuity of multiple requesters during its movement; if not, the content provider does not perform any additional operations on the content; the content provider completes all current services. The amount is not less than After the full sample of the content of the switching service threshold is pushed, the mobile switching process is completed. The invention solves the problems that the request message cannot be responded and the communication of multiple requesters is interrupted due to the mobile switching of the content provider.

Description

Content provider mobile switching method in content-centric network

technical field

The invention relates to a mobile switching method for a content provider in a content-centric network (Content Centric Networking), and belongs to the technical field of mobile communication networks.

Background technique

With the rapid development of the Internet, users' demand for content information is becoming more and more obvious and strong. Now, content services including text, images or video on demand have become the main body of network services. Usually, people don't care about the source of content, but only care about the content itself, or the speed and quality of content transmission, or whether the content is safe or not. However, the current host-centric traditional IP network architecture cannot adapt to changes in the upper-layer application model, and it is difficult to meet people's needs for content acquisition. Therefore, various supporting technologies of CCN (Content Centric Networking) have become a research hotspot of the next generation Internet architecture.

The content-centric network CCN focuses on the content itself, and uses the content name (Content Name) to identify the content, and can also separate the content from the content storage location through the content name. CCN also implements caching of network content, which can be fetched from neighboring routers that cache the content. In this way, it provides natural support for data security, mobility and multicast.

In a content-centric network CCN, a content provider can serve multiple content requesters. If the content provider has a mobile switch, if the content requester cannot perceive its mobile switch, it will still send a request message to the original location of the content provider, so that the request message cannot be responded to, resulting in the interruption of communication among multiple requesters. At this time, the content provider needs to establish handover procedures for multiple requesters separately, resulting in high signaling overhead and complicated handover process, so the research on the mobility of the content provider is very necessary, urgent and important.

In CCN, the movement of the content provider has a greater impact on normal communication, because after the content provider switches, all relevant routers in the network need to be notified to update the routing table, resulting in the request message not being sent to the content provider in a timely and accurate manner. In addition, the content requester cannot know whether the data packet cannot be returned due to network problems or node mobility, which affects normal communication. Furthermore, if a large number of content providers move at the same time, normal communication will also be affected.

At present, some technical solutions have been developed to solve the problem of content provider mobility in the CCN network. The following four types of existing technologies and their defects are introduced in detail to solve the problem of content provider mobility:

The first type is a rendezvous point (Rendezvous Point) method, which uses a location management server supporting CCN mobility as a meeting point to implement name resolution between the content name and the location of the content provider. After the content provider moves, send a message to the rendezvous server to update the location of the content provider. After the requester makes a location query within a set time, the server at the meeting point responds to establish a new connection. Its defect is that the update/query of the new content name and the establishment of the FIB will cause a large time delay.

The second category is the indirection point (Indirection Point) method, the indirection point is a permanent server for maintaining a series of bindings between the target prefix (target prefix) and the source prefix (source prefix). All requests to the content provider must first reach the indirect point, where the original request is encapsulated and then tunneled to the current location. Therefore, all the user's request packets will arrive at the indirect point first, which not only easily leads to a single point of failure, but also increases the content acquisition time of the requester to a considerable extent when the indirect point is not on the shortest path between the content provider and the requester , wasting network bandwidth resources.

The third category is the tunnel redirection method, in which the tunnel is used to redirect the request packet to a new location of the content provider. When the content provider moves to another access point, in order to continue to receive the request packet sent by the content requester, the content provider will send a prefix update message (PU) to the home router. In the future, all request packets will be routed to the home router of the content provider for encapsulation, and then sent to the current location of the content provider. When the home router is not on the shortest path between the user and the current location of the content provider, this mechanism will increase the content acquisition time of the requester to a certain extent, wasting network bandwidth resources. In addition, due to the need to add a prefix to deliver the request packet to the correct destination address, the tunnel-based redirection method has a high packet delivery cost.

The fourth type is a route-based method. In this method, when a content provider is about to perform a mobile handover, it needs to send handover notification information to the previous hop access router. At this time, the access router receives all request packets sent to the content provider and cache. When the content provider moves and switches to a new access router, it sends a virtual request "virtualinterest" message, which carries the name information of the content provider, and the network will forward it to its original access router according to the longest prefix matching principle in the FIB table. Incoming routers, at this time, all routers passing through must update the interface information corresponding to the content name in the FIB table. After receiving the "virtual interest" message, the original router of the content provider sends the buffered Interest message back to the content provider, and the subsequent Interest packets can be forwarded directly according to the FIB table without going through its original access forwarded by the router. Although this method reduces the path update overhead and switching delay; however, since the content provider always keeps the content name unchanged during the mobile switching process, the route aggregation convergence problem after the switching is not considered, and the entries in the FIB table will be too large , burdening the router. Moreover, all intermediate routers have to update their respective FIBs, causing the capacity of the routing table to increase rapidly. When the number of content requesters and the frequency of mobile switching increase, this situation will become more serious.

Then introduce the content and defects of the technical solutions in the current two related invention patent application documents as follows:

"A Mobility Management Method for Information Center Network Based on Content Popularity" (Application No. 201310471355.4) divides content into two types according to content popularity, and implements two different mobility management methods for content with different popularity : Based on proxy nodes and network cache. After the content provider moves, if the popularity of the content is less than the threshold K, the proxy node-based mobility management method is used, that is, the proxy node caches the interruption request, updates the content name prefix, and routes the interest packet to the content provider. If the content popularity is greater than the threshold value K, then use the mobility management method based on the network cache, that is, resend the interest packet and broadcast it in the domain. In the proxy node-based mobility management method, the Interest packet is rerouted to the content provider by updating the content name prefix. This method has obvious disadvantages: the signaling overhead for maintaining the mapping between the old and new content name prefixes is relatively large.

The method of "A Mobility Supporting Method in a Content-Centric Network" (Application No. 201310315590.2) is to assign a special location to each router in the CCN network, and assume that the content name is based on the original access router location of the content provider . After the content provider completes the mobile switching, the current access router sends a handover completion message to the original access router, so that the current access router adds a corresponding FIB entry for the content provider, and the original access router updates the corresponding FIB entry of the content provider, and then send the request message at the original location of the content provider to the new location. In this invention application, the content of the content provider needs to be renamed, and there is also the problem of aggregation of the routing table due to the updating of the routing table.

Contents of the invention

In view of this, the object of the present invention is to provide a content provider mobile switching method in a content-centric network. The method of the present invention is to provide each content whose current service quantity is not less than the switching service threshold before the content provider moves. The complete sample is pushed to the original access router of the content provider by sending the sample push data packet. And after the push of these contents is completed, the content provider starts to move, which can ensure the continuity of the communication process of multiple content requesters before and after the mobile switching of the content provider, thus better solving the existing problems caused by content requests. The operator cannot perceive the mobile switching of the content provider, causing the request message to be unresponsive and the communication to be interrupted.

In order to achieve the above object, the present invention provides a mobile switching method for a content provider in a content-centric network, which is characterized in that: the content provider records the current service quantity of each content it provides, and sets the switching service according to the actual mobile demand Threshold; the switching service threshold is the threshold set by the content provider for judging whether to actively push the content to its original access router before its mobile switching according to the current service quantity of each content it provides; Before the content provider moves, first judge whether the current service quantity of each content is greater than or equal to the switching service threshold at this time, and if so, send the complete sample of the content whose current service quantity is greater than or equal to the switching service threshold, and send the sample push data Packets are pushed to the original access router of the content provider, so that multiple requesters who request the content can continue to obtain services through the original access router of the content provider, ensuring that during the content provider’s moving process Among them, the communication continuity of the multiple requesters; if not, that is, the current service quantity of the content is less than the switching service threshold, the content provider does not perform any additional operations on the content; the content provider completes all the current service quantity is not less than the switching service threshold After the push of the complete sample of the content of the service threshold, the mobile handover process is completed.

The method comprises the following steps:

(1) The content provider records the current service quantity of each content it provides, and sets the switching service threshold according to the actual mobile demand;

(2) Before moving, the content provider first judges whether the current service quantity of each content is greater than or equal to the switching service threshold, if so, then executes the subsequent step (3); if not, the content provider starts the mobile switching process , and jump to step (7):

(3) The content provider actively pushes the complete sample of each content whose current service quantity is greater than or equal to the switching service threshold to the original access router of the content provider by sending a sample push data packet;

(4) After the original access router of the content provider receives the sample push data packet, it first caches the content in the sample push data packet; then sends a sample confirmation feedback packet to the content provider;

(5) The content provider completes the push operation of all complete samples of content whose current service quantity is not less than the switching service threshold, and starts the mobile switching process after receiving the sample confirmation feedback package of all content;

(6) During the mobile handover of the content provider, because the original access router of the content provider has cached complete samples of the content whose current service quantity is greater than or equal to the switching service threshold, multiple requesters who request these contents still pass through The original access router of the content provider continues to obtain the service, ensuring the continuity of the multi-requester communication;

(7) After the mobile switching of the content provider is completed, the content service request is processed according to the current network state: a response is obtained from the original access router of the content provider or the new location of the content provider.

The sample push data packet is formed by adding an option field Sample PushFlag on the basis of the traditional data packet: Sample Push Flag=1 is the sample push data packet, and Sample Push Flag=0 is the traditional data packet.

The sample push data packet is a dedicated data packet sent by the content provider to the original access router of the content provider. The original access router of the content provider, so that the original access router of the content provider caches the content information after receiving the sample push data packet.

The sample acknowledgment feedback packet is formed by adding an option field Sample AckFlag on the basis of the traditional request packet: Sample Ack Flag=1 is the sample acknowledgment feedback packet, and Sample Ack Flag=0 is the traditional request packet.

The sample confirmation feedback packet is a confirmation packet sent back to the content provider after the original access router of the content provider receives the sample push data packet and caches the content in it.

The innovative feature of the method of the present invention is: before the mobile switching, the content provider should record the current service quantity of each content it provides, and set the switching service threshold according to the actual mobile demand—for judging whether to actively push the content to its The threshold set by the original access router. In addition, the sample push data package and the sample confirmation feedback package are defined. When the current service quantity of the content provided by the content provider is greater than or equal to the switching service threshold, the content provider sends a complete sample of the content by sending a sample push data package. Push to the original access router of the content provider, so that during its mobile switching, the continuity of the communication process of multiple requesters requesting the content is guaranteed. After the mobile switching of the content provider is completed, the content service request is processed according to the current network state: responses are obtained from the original router of the content provider or the new location of the content provider.

In a word, the present invention can ensure that the request message is responded in time during the mobile switching process of the content provider, and the continuity of multiple content requesters in the whole communication process.

The operation steps of the method of the present invention are simple, easy and convenient, better solve the disadvantages of the prior art, and have good prospects for popularization and application.

Description of drawings

FIG. 1 is a schematic diagram of an application scenario of a mobile switching method for a content provider in a content-centric network of the present invention.

FIG. 2 is a flow chart of the operation steps of the content provider mobile switching method in the content-centric network of the present invention.

Fig. 3 is a sequence diagram of the content provider mobile switching method in the content-centric network of the present invention.

detailed description

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings.

Referring to FIG. 1 , the application scenario of the method of the present invention is introduced: a content provider server provides services for multiple requesters (requester 1, requester 2..., requester n). The router that the content provider server is connected to before the mobile switching is R1, and the router that the content provider server is connected to after the mobile switching is R2.

Before switching and moving, the content provider server pushes a complete sample of each content whose current service quantity is greater than or equal to the switching service threshold to R1 in the form of a sample push data packet. After the push is completed, there is a cache of relevant content in R1 . During the mobile switching of the content provider server, the requester does not know that the content provider has moved, and the request message is still sent to the original location of the content provider server. At this time, these request messages can get a response from R1, which can ensure the communication of the requester continuity. After the mobile switching of the content provider server is completed, the unfinished requests and new requests are forwarded according to the existing routing mechanism, and services can be obtained from the original access router R1 of the content provider server, or from the new router R1 of the content provider server. The location is responded to.

The present invention is a content provider mobile switching method in a content-centric network: the content provider records the current service quantity of each content it provides, and sets the switching service threshold according to the actual mobile demand; the switching service threshold is the content provider According to the current service quantity of each content provided by it, it is used to judge whether to actively push the content to the router it originally accessed before the mobile handover; Whether the current service quantity of each content is greater than or equal to the switching service threshold, and if so, push the complete sample of the content whose current service quantity is greater than or equal to the switching service threshold to the content provider by sending sample push data packets The original access router, so that multiple requesters who request the content can continue to obtain services through the original access router of the content provider, and ensure the continuity of communication between the multiple requesters during the movement of the content provider If not, that is, the current service quantity of the content is less than the switching service threshold, the content provider will not perform any additional operations on the content; after the content provider completes the push of all the complete samples of the content whose current service quantity is not less than the switching service threshold to complete the mobile switching process.

Referring to Fig. 2 and Fig. 3, introduce the following specific operation steps and sequence diagram thereof of the inventive method:

Step 1. The content provider records the current service quantity of each content it provides, and sets the switching service threshold according to the actual mobile demand;

Step 2, before the content provider moves, first judge whether the current service quantity of each content is greater than or equal to the switching service threshold, if so, then perform the subsequent step (3); if not, then the content provider starts the mobile switching process , and jump to step (7):

Step 3, the content provider actively pushes the complete sample of each content whose current service quantity is greater than or equal to the switching service threshold to the original access router of the content provider by sending a sample push data packet;

Step 4: After receiving the sample push data packet, the original router of the content provider caches the content in the sample push data packet; then sends a sample confirmation feedback packet to the content provider;

Step 5: The content provider completes the push operation of all complete samples of content whose current service quantity is not less than the switching service threshold, and starts the mobile switching process after receiving the sample confirmation feedback package of all content;

Step 6: During the mobile handover of the content provider, because the original access router of the content provider has cached complete samples of the content whose current service quantity is greater than or equal to the switching service threshold, multiple requesters who request these contents still pass through The original access router of the content provider continues to obtain the service, ensuring the continuity of the multi-requester communication;

Step 7: After the mobile switching of the content provider is completed, the content service request is processed according to the current network status: a response is obtained from the original router of the content provider or the new location of the content provider.

Because the method of the present invention defines two new data packets: the sample push data packet and the sample confirmation feedback packet, which are described in detail below:

The sample push data packet is formed by adding an option field Sample Push Flag on the basis of the traditional data packet: Sample Push Flag=1 is a sample push data packet, and Sample Push Flag=0 is a traditional data packet.

The sample push data packet is a dedicated data packet sent by the content provider to the original access router of the content provider. Its purpose is to push the complete sample of the content whose current service quantity is greater than or equal to the switching service threshold to the content provider. The original access router, so that the original access router of the content provider caches the content information therein after receiving the sample push data packet. The header structure of the sample push data packet is shown in the following table:

Content Name Signature Signed Info (Signed Info) (content source identification, key location, expiration time) Content (Data) Option field (Sample Push Flag=1)

In the CCN mechanism, when a traditional data packet arrives at the router, the router first checks the PIT table. If there is an entry with the same content name as that in the data packet in the PIT table, the router caches the content in the data packet and saves the data packet Forward the packet according to the interface in the entry; otherwise, discard the packet. After the router receives the sample push data packet, because there is no record corresponding to the content name in the sample push data packet in the PIT table, the operation performed by the router is to cache the content in the sample push data packet, and then discard the sample push data packet.

The sample acknowledgment feedback packet is also based on the traditional request packet, and the option field Sample Ack Flag is added: Sample Ack Flag=1 is the sample acknowledgment feedback packet, and Sample Ack Flag=0 is the traditional request packet. The sample confirmation feedback packet is a confirmation response packet sent back to the content provider after the original access router of the content provider receives the sample push data packet and caches the content in it. The header structure of the sample data feedback packet is shown in the following table:

The method of the present invention has carried out many implementation tests, and the results of these tests show that the method of the present invention is successful and realizes the purpose of the invention.

Claims (6)

1. A content provider mobile switching method of a content-centric network (Content Centric Networking), characterized in that: the content provider records the current service quantity of each content it provides, and sets the switching service threshold according to actual mobile needs; The switching service threshold is a threshold set by the content provider based on the current service quantity of each content provided by the content provider for judging whether to actively push the content to the router it originally accessed before the mobile switching; the content provider Before the person moves, first judge whether the current service quantity of each content is greater than or equal to the switching service threshold at this time. The method is pushed to the original access router of the content provider, so that multiple requesters who request the content can continue to obtain services through the original access router of the content provider, ensuring that during the moving process of the content provider, The continuity of the multiple requester communications; if no, that is, the current service quantity of the content is less than the switching service threshold, the content provider does not perform any additional operations on the content; the content provider completes all the current service quantity is not less than the switching service threshold After the push of the complete sample of the content, complete the mobile switching process. 2. The method according to claim 1, characterized in that: said method comprises the following steps: (1) The content provider records the current service quantity of each content it provides, and sets the switching service threshold according to the actual mobile demand; (2) Before moving, the content provider first judges whether the current service quantity of each content is greater than or equal to the switching service threshold, if so, then executes the subsequent step (3); if not, the content provider starts the mobile switching process , and jump to step (7): (3) The content provider actively pushes the complete sample of each content whose current service quantity is greater than or equal to the switching service threshold to the original access router of the content provider by sending a sample push data packet; (4) After the original access router of the content provider receives the sample push data packet, it first caches the content in the sample push data packet; then sends a sample confirmation feedback packet to the content provider; (5) The content provider completes the push operation of all complete samples of content whose current service quantity is not less than the switching service threshold, and starts the mobile switching process after receiving the sample confirmation feedback package of all content; (6) During the mobile handover of the content provider, because the original access router of the content provider has cached complete samples of the content whose current service quantity is greater than or equal to the switching service threshold, multiple requesters who request these contents still pass through The original access router of the content provider continues to obtain the service, ensuring the continuity of the multi-requester communication; (7) After the mobile switching of the content provider is completed, the content service request is processed according to the current network state: a response is obtained from the original access router of the content provider or the new location of the content provider. 3. The method according to claim 1, characterized in that: the sample push data packet is formed on the basis of the traditional data packet by adding an option field Sample Push Flag: Sample Push Flag=1 is the sample push data packet , Sample Push Flag=0 is a traditional data packet. 4. The method according to claim 3, characterized in that: the sample push data packet is a dedicated data packet sent by the content provider to the original access router of the content provider, and its purpose is to send the current service quantity greater than Or the complete sample of the content equal to the switching service threshold is pushed to the original access router of the content provider, so that the original access router of the content provider caches the content information therein after receiving the sample push data packet. 5. The method according to claim 2, characterized in that: the sample acknowledgment feedback packet is formed on the basis of the traditional request packet by adding the option field Sample Ack Flag: Sample Ack Flag=1 is the sample acknowledgment feedback packet , Sample Ack Flag=0 is a traditional request packet. 6. The method according to claim 5, characterized in that: the sample confirmation feedback packet is the content provider’s original access router that receives the sample push data packet and completes the content cache, and then feeds back to the content provider Confirmation packet sent.