WO2020118571A1

WO2020118571A1 - Method and system for transmitting ip data packet by using content centric network as tunnel

Info

Publication number: WO2020118571A1
Application number: PCT/CN2018/120686
Authority: WO
Inventors: 李挥; 徐睿; 邬江兴; 伊鹏; 朱伏生; 李胜飞; 陈世胜; 唐宏; 张云勇; 魏进武; 陈孟尝; 朱强; 王博辉; 邢凯轩; 阙建明; 李文军
Original assignee: 北京大学深圳研究生院; 国家数字交换系统工程技术研究中心
Priority date: 2018-12-12
Filing date: 2018-12-12
Publication date: 2020-06-18

Abstract

The present invention is applicable to the field of network technology improvement, and provides a method for transmitting an IP data packet by using a content centric network (CCN) as a tunnel, comprising: S1, divide a CCN into an application layer, a content layer, a data link layer, and a physical layer, and map a content name in the CCN into an MAC address for query; S2, construct an FIB table item, a PIT table item, and a CS cache table item in an FWD according to a link layer transmission technology in the layered CCN to form a new CCN; S3, deploy a pair of switch nodes having a dual stack function on a border of an IP network and the new CCN, and respectively connect the switch nodes to a sending terminal and a receiving terminal of a TCP to construct the TCP/CCN; and S4, IP data completes data packet transmission in the TCP/CCN by means of multiple interest packet exchanges. According to the method, the transmission efficiency is effectively improved, an in-network cache characteristic of the CCN is fully used, the transmission effectiveness is improved, and a lower-layer transmission resource is fully used.

Description

Name of the invention: A method and system for transmitting IP data packets using a content-centric network as a tunnel

Technical field

[0001] The present invention belongs to the field of network technology improvement, and particularly relates to a method and system for transmitting IP data packets using a content-centric network as a tunnel.

Background technique

[0002] In the past half century, the Internet has experienced a high-speed development process from scratch, from simple to complex, and the network system based on the IP protocol has shown tenacious vitality in the continuous improvement, making the computer network toward Socialization and globalization have developed steadily. However, the design of the IP network based on address routing is to achieve end-to-end communication. The end-to-end transmission mode of the IP network enables the successful deployment of the IP network. However, IP networks seem to be incapable of transmitting in very large-scale information centers. Problems such as exhaustion of IP addresses, security flaws, weak management and control capabilities, weak support for mobility, and poor service adaptability have accelerated the exploration of next-generation Internet systems. In recent years, many revolutionary network architecture schemes have been proposed. Among these schemes, ICN is considered to be a new type of network architecture that can better meet users' information transmission needs.

[0003] ICN abandons the IP network address-centric end-to-end communication mode, but adopts the content-centric end-to-end network communication mode. CCN is an information-centric network architecture proposed by the Palo Alto Research Center, focusing on the information itself, not the location of the information, and launched the CCNx project to implement a deployable prototype system. NDN is one of the projects supported by the National Natural Science Foundation of the future based on the CCN idea. CCN replaces addresses with the network communication model of information, abandons the end-to-end communication mode, and obtains information in an active "pull" way. The security mechanism is built on the information itself. The routing mechanism makes full use of the node cache. The architecture supports mobility and solves The problem of large-scale information transmission. At the same time, CCN uses the hierarchical content name as the routing identifier for routing addressing. The content request is sent through the Interest message. The Data message uses the reverse path to return the content for information transmission. In CCN, the content name is used as the unique identifier of the content. For content positioning, routing and transmission. Therefore, CCN can better meet people's demand for information-centric communication.

[0004] As a future network, the long-term goal of content-centric networks is to replace IP networks. However, 5 see some The content center network still transmits data packets on the IP network in an overlay manner. In essence, the data packets are still transmitted through the IP network, and the underlying transmission resources are not fully utilized. 5 See some work. CCN uses TCP, UDP, or IP as a tunnel during deployment. This usually requires manual deployment of the tunnel endpoints. When a new CCN deployment is required, the tunnel needs to be changed manually. In addition, these point-to-point tunnels limit CCN's ability to use the bottom layer to transmit media. In order to make full use of content-centric communication and simplify the deployment process, it is advisable to deploy CCN nodes directly via Ethernet.

[0005] At the same time, the existing IP network still shows strong vitality in many aspects, and many existing services are provided through the IP protocol. If the traditional IP network is directly replaced on a large scale, it is difficult to implement at this stage, and it usually requires gradual Deploy to achieve a smooth transition. In order to make full use of the underlying transmission resources and achieve compatibility with existing traditional networks and smooth transitions, it is advocated that future network development is compatible with existing network systems. The compatibility of the content center network with the traditional network is of great significance, and is of great significance for the future development and evolution of the network.

[0006] At present, the academic community has mainly proposed several sets of solutions for the integration of ICN and existing IP networks, of which the more well-known is the TCP/ICN solution. This solution provides basic ideas, but still faces many problems, so further improvement is needed. The main technical solution of TCP/ICN is specially designed for two difficulties. The first difficulty is that the ICN network is a content-centric network and the IP network is an end-to-end network. The second difficulty is that the IP network is a A network that actively "pushes" data, and the ICN network is a network that actively "pulls" data. This patent mainly considers implementing this method on a CCN network.

[0007] The TCP/ICN technical solution has designed a pair of switching nodes-"sending agent" and "receiving agent" at the junction of the IP network and the ICN network. The sending agent connects to the IP network that actively sends data, and the receiver connects to the destination IP network. The conversion of the protocol and the decapsulation of the package are completed in this pair of agents.

[0008] The data transmission in the ICN network adopts a "pull" mode, that is, each data packet requires an interest packet to make a request, so if the sending end needs to directly send TCP data, special processing needs to be done at the sending agent . When the sending agent receives the TCP data that needs to be sent, the sending agent first sends an interest packet to notify the receiving agent that there is a data packet that the receiving agent needs to pull. At the same time, the sending agent caches the TCP data packet. Then, when the receiving agent receives the notification interest packet, the receiving agent sends an interest packet requesting data to the sending agent. When the sending agent receives the interest packet, the sending agent sends the TCP data buffered to the receiving agent. After receiving the data packet, the receiving agent unpacks it, and then The content is transmitted to the receiving end through the IP network. After receiving the TCP data, the receiving end then sends an ACK response, thus completing the process of TCP transmission through the ICN network.

[0009] It is seen that some of the solutions are deployed on the overlay ICN. In essence, there is no gradual deployment of the two network architectures. In-depth analysis of the TCP/IP three-way handshake and four-way wave process and the CCN network acquisition The content process, in order to make better use of the underlying resources to transmit media, simplify the deployment of CCN, directly deploy CCN on the Ethernet link layer, and consider combining with TCP/IP to realize the progressive deployment and smooth transition of the network system.

[0010] The main problem is that the transmission efficiency is not high. Originally in the TCP network, sending data only needs to send and confirm two packets, and in the CCN network, an additional interest packet needs to be added to notify the receiving agent Pulling data, this undoubtedly increases system overhead and reduces transmission efficiency. At the same time, the CCN network has the characteristics of in-network caching, which is not used, which will reduce the effectiveness of the entire transmission.

[0011] 5 See if there is technology or TCP/CCN design in overlay-based CCN network, CC is not fully utilized

N is the underlying transmission resource for media data transmission. In essence, it is still the IP network for data packet transmission. The current CCN is only a logical CCN, and the underlying transmission resources are not better used.

[0012] See that there are technical solutions that do not consider the combination of Ethernet-based CCN networks and TCP/IP networks.

The transmission of the underlying data packets of the CN network is still carried out through the IP network. Essentially, the IP network is considered to be combined with the traditional CCN network, and the combination of the CCN network based on Ethernet and the traditional IP network is not fully considered to realize the progressive deployment and smoothness of the network. transition.

[0013] In the past, the traditional tunneling method is directed to the content network based on the IP network layer as the bottom layer, without considering the content network based directly on the link layer.

Summary of the invention

technical problem

Solution to the problem

Technical solution

[0014] An object of the present invention is to provide a method and system for transmitting IP data packets using a content-centric network as a tunnel, and aims to solve the above-mentioned technical problems.

[0015] The present invention is implemented in this way, a method for transmitting IP data packets using a content center network as a tunnel, the method includes the following steps: [0016] SI, dividing the CCN network into an application layer, a content layer, a data link layer and a physical layer and mapping content names in the CCN network to MAC address queries;

[0017] S2, in the layered CCN network according to the link layer transmission technology to build FIB entries, PIT entries and CS cache entries in the FWD to form a new CCN network;

[0018] S3. Deploy a pair of transit nodes with dual stack functions at the boundary of the IP network and the new CCN network to connect to the sending end and receiving end of TCP respectively to construct a TCP/CCN network;

[0019] S4. In the TCP/CCN network, IP data completes data packet transmission through multiple interest packet exchanges.

[0020] A further technical solution of the present invention is: the FIB entry is generated by a routing protocol, the FIB entry does not change during operation, and the FIB entry provides a search service for the Interest packet processing module.

[0021] A further technical solution of the present invention is: the arrival interface of the Interest packet recorded in the PIT entry, before forwarding the Interest packet, the CCN node records the physical network port and source MAC address it arrives in the PIT entry, To provide the forwarding basis for the responded Data packets, the PIT table entry needs to support search, insert and delete functions.

[0022] A further technical solution of the present invention is: The CS cache supports operations of searching, reading, inserting, replacing, and deleting. When an Interest package or a Data package arrives, a matching search is first performed in the CS cache, according to the cache strategy Maintain the accessed state for cached content.

[0023] A further technical solution of the present invention is: The data transmission process in step S4 includes the following steps: [0024] S411, after receiving the TCP segment, the sending agent converts the data to be transmitted into the form of a CCN data packet and generates a The interest package informs the receiving agent that there is data to be fetched;

[0025] S412: After receiving the interest packet, the receiving agent sends the request data interest packet to the receiving agent;

[0026] S413: The receiving agent receives the request data interest packet, decapsulates the encapsulated data packet, transmits the encapsulated TCP segment to the TCP receiving end through the IP network, and sends back an ACK response.

[0027] A further technical solution of the present invention is: The TCP/CCN network establishing connection in the step S4 includes the following steps:

[0028] S421, the sending agent receives the SYN sent by the sending end;

[0029] S422, the receiving agent sends the interest packet with the SYN logo to the receiving agent via the CCN network and receives it;

[0030] S423: The receiving end receives the receiving and receiving agent to send SYN and sends SYN+ACK to the receiving agent;

[0031] S424, the receiving agent sends the interest packet with the SYN and ACK signs to the sending agent via the CCN network;

[0032] S425: The sending end receives the SYN and ACK sent by the sending agent and generates a sending ACK transmission to the sending Send agent

[0033] S426: The sending agent sends the interest packet with the sending ACK identifier to the receiving agent via the CCN network;

[0034] S427. The receiving agent sends the interest packet with the sending ACK identifier to the receiving end.

[0035] A further technical solution of the present invention is: The disconnection of the TCP/CCN network connection in the step S4 includes the following steps:

[0036] S431. The sending agent receives the FIN sent by the sending end, and forwards the interest packet with the FIN identification of the sending end to the receiving agent via the CCN network;

[0037] S432. The receiving agent transmits the interest packet with the FIN identifier of the sending end to the receiving end;

[0038] S433, the receiving agent receives the ACK sent by the receiving end, and forwards the interest packet with the ACK identifier of the receiving end to the sending agent via the CCN network;

[0039] S434. The sending agent transmits the interest packet with the ACK identifier of the receiving end to the sending end;

[0040] S435, the receiving agent receives the FIN sent by the receiving end, and forwards the interest packet with the FIN identification of the receiving end to the sending agent by the CCN network;

[0041] S436: The sending agent transmits the interest packet with the FIN identification of the receiving end to the sending end;

[0042] S437. The sending agent receives the ACK sent by the sending end, and forwards the interest packet with the ACK identifier of the sending end to the receiving agent via the CCN network;

[0043] S438. The receiving agent transmits the interest packet with the ACK identifier of the sending end to the receiving end.

[0044] Another object of the present invention is to provide a content center network as a tunnel transmission IP data packet system, characterized in that the system includes

[0045] A partitioning module for dividing the CCN network into an application layer, a content layer, a data link layer and a physical layer and mapping content names in the CCN network to MAC address queries;

[0046] a building module for constructing a FIB entry, a PIT entry and a CS cache entry in the FWD in the layered CCN network according to the link layer transmission technology to form a new CCN network;

[0047] Build a network module for deploying a pair of transit nodes with dual stack functions at the boundary between the IP network and the new CCN network to connect to the TCP sender and receiver respectively to build a TCP/CCN network;

[0048] A data exchange module, configured to complete data packet transmission of IP data through multiple interest packet exchanges in a TCP/CCN network.

[0049] A further technical solution of the present invention is: the FIB entry is generated by a routing protocol, and the FIB entry is at No change will occur during operation, and the FIB entry provides a search service for the Interest package processing module.

[0050] A further technical solution of the present invention is: the arrival interface of the Interest packet recorded by the PIT entry, before forwarding the Interest packet, the CCN node records the physical network port and source MAC address it arrives in the PIT entry, To provide the forwarding basis for the responded Data packets, the PIT table entry needs to support search, insert and delete functions.

[0051] A further technical solution of the present invention is: The CS cache supports operations of searching, reading, inserting, replacing, and deleting. When the Interest package or the Data package arrives, a matching search is first performed in the CS cache, according to the cache strategy Maintain the accessed state for cached content.

[0052] A further technical solution of the present invention is: The data transmission process in the data exchange module includes the following units

[0053] an interest packet sending unit, which is used for the sending agent to convert the data to be transmitted into the form of a CCN data packet after receiving the TCP segment and generate an interest packet to inform the receiving agent that there is data to be fetched;

[0054] Sending a request data packet unit, for the receiving end to receive the interest packet received by the agent and send the request data interest packet to the receiving agent;

[0055] The decapsulation transmission unit is used to receive the request data interest packet to decapsulate the encapsulated data packet, transmit the encapsulated TCP segment to the TCP receiving end through the IP network and send back an ACK response.

[0056] A further technical solution of the present invention is: the TCP/CCN network establishment connection in the data exchange module includes the following units

[0057] The first SYN unit for the sending agent to receive the SYN sent by the sending end;

[0058] The first SYN marked interest packet sending unit is used by the receiving agent to send the interest packet with the SYN logo to the receiving agent via the CCN network and receive it;

[0059] Send SYN and ACK unit, for the receiving end to receive the receiving agent to send SYN and send SYN+ACK to the receiving agent;

[0060] transmitting a SYN and ACK identification interest packet unit, used by the receiving agent to send the SYN and ACK identification interest packet to the sending agent via the CCN network;

[0061] The transmission band sending ACK unit is used for the sending end to receive the SYN and ACK sent by the sending agent and generate a sending ACK transmission to the sending agent;

[0062] The transmission belt sends an ACK identification interest packet unit for the sending agent to send the interest packet with the sending ACK identification to the receiving agent via the CCN network; [0063] The receiving agent with an interest packet with a sent ACK identifier unit receives an interest packet with a sent ACK identifier to the receiving end.

[0064] A further technical solution of the present invention is: The disconnection of the TCP/CCN network connection in the data exchange module includes the following units

[0065] The first receiving and forwarding unit is used for the sending agent to receive the FIN sent by the sending end, and forwards the interest packet with the FIN identification of the sending end to the receiving agent via the CCN network;

[0066] The first transmission unit is used for the receiving agent to transmit the interest packet with the FIN identification of the sending end to the receiving end; [0067] The second receiving and forwarding unit is used for the receiving agent to receive the ACK sent by the receiving end, and The CCN network forwards the interest packet with the ACK identification of the receiving end to the sending agent;

[0068] The second transmission unit is used for the sending agent to transmit the interest packet with the ACK identifier of the receiving end to the sending end; [0069] The third receiving and forwarding unit is used for the receiving agent to receive the FIN sent by the receiving end, and The CCN network forwards the interest packet with the FIN identification of the receiving end to the sending agent;

[0070] The third transmission unit is used for the sending agent to transmit the interest packet with the FIN identifier of the receiving end to the sending end; [0071] The fourth receiving and forwarding unit is used for the sending agent to receive the ACK sent by the sending end, and The CCN network forwards the interest packet with the ACK identifier of the sending end to the receiving agent;

[0072] The fourth transmission unit is used for the receiving agent to transmit the interest packet with the ACK identifier of the sending end to the receiving end.

Beneficial effects of invention

Beneficial effect

[0073] The beneficial effects of the present invention are: This method effectively improves the efficiency of transmission, makes full use of the cache characteristics of the CCN network, improves the effectiveness of transmission, makes full use of the underlying transmission resources, making the CCN network and the traditional IP network Combined to realize the gradual deployment and smooth transition of the network.

Brief description of the drawings

BRIEF DESCRIPTION

[0074] FIG. 1 is a schematic diagram of a CCN node framework provided by an embodiment of the present invention.

[0075] FIG. 2 is a schematic design diagram of a CCN node combined with a MAC address provided by an embodiment of the present invention.

[0076] FIG. 3 is a schematic diagram of a frame format design in a CCN node combined with a MAC address provided by an embodiment of the present invention.

[0077] FIG. 4 is a schematic diagram of Face design in a CCN node combined with a MAC address provided by an embodiment of the present invention.

[0078] FIG. 5 is a schematic diagram of a CCN node design combined with a MAC address provided by an embodiment of the present invention. 6 is a schematic diagram of TCP/CCN conversion provided by an embodiment of the present invention.

7 is a schematic diagram of an IP overlay CCN provided by an embodiment of the present invention.

[0081] FIG. 8 is a schematic diagram of TCP connection establishment provided by an embodiment of the present invention.

[0082] FIG. 9 is a schematic diagram of TCP connection disconnection provided by an embodiment of the present invention.

Invention Example

Embodiments of the invention

[0083] ICN: Information Centric Network, information center network.

[0084] CCN: Content Centric Network, content center network.

[0085] NDN: Named Data Networking, named data network.

[0086] TCP: Transmission Control Protocol, transmission control protocol.

[0087] IP: Internet Protocol, Internet Protocol.

[0088] ACK: Acknowledgement, that is, an acknowledgment character, a type of transmission control character sent by a receiving station to a sending station in data communication.

[0089] MAC: Media Access Control Address, media access control address,

[0090] FIB: Forwarding Information Base, forwarding information base, which refers to a forwarding table used for query forwarding in the NDN network.

[0091] PIT: Pending Interest Table, a pending interest table, which refers to a data structure maintained by a router in the NDN network and used to wait for a reply of an interest packet.

[0092] CS: Content Store, content storage library, refers to the data structure used to cache data in the NDN network [0093] Interest package: Interest package (Interest Message), issued by the subscriber, request data by Name

, Can clearly determine the requested content package. Interest package is NDN Network (Named Data

Networking) A message type in the CCNX protocol.

[0094] Data package: Content Object (content package), published by the publisher as a response to the interest package, including data load, publisher information, and signature information used for verification, etc. The content package is a Message type in the NDN Network (Named Data Networking) protocol.

[0095] FWD forward daemon

[0096] The present invention provides a method and system for tunneling an IP network system data packet for a content-centric network system, and proposes a method for enabling IP data packets to pass through a content network system tunnel based directly on a link layer Method. In the past, the traditional tunneling method was aimed at the content network based on the IP network layer as the bottom layer, and did not consider the content network based directly on the link layer. The present invention is proposed to solve this problem by adopting the content based on the Ethernet layer as the bottom layer. The network establishes a tunnel to provide transmission services for IP data.

[0097] The present invention proposes a new type of network protocol stack. It is planned to deploy and execute the CCN network directly on the link layer via Ethernet, thereby omitting the additional steps of modifying existing protocols and making full use of the underlying transmission resources.

[0098] Afterwards, the present invention proposes a method and system tunneling technical solution for tunneling IP network system data packets in a content-centric network system, so that data packets of the IP network can be transmitted through the content-center network based on the Ethernet layer.

[0099] Direct deployment of CCN on Ethernet

[0100] See that there are many specific deployments of CCN that use IP networks as tunnel transmission channels, which not only violates C

The original intention of CN to replace IP, and it inevitably brings inefficiency problems. Therefore, we propose a method of directly deploying the CCN network on the Ethernet.

[0101] The CCN node can send interest packets and data packets by unicast or broadcast on the MAC address in the data link layer. For clarity, we will focus on the interface face of the CCN node. We design the CCN node to pass The face interface is connected to the MAC address (Ethernet link layer) to share media data. Therefore, we divided the entire CCN network into an application layer, a content layer, and a data link layer, so that the traditional network that was canceled uses IP as the transmission address. As shown in Figure 1 and 2.

[0102] Overall Architecture and Functional Description

[0103] The source and destination MAC addresses in the Ethernet frame are the identifications of the physical devices on both sides of the communication. Most current Ethernets use a star structure, and a physical network port can be connected to multiple devices. Therefore, both in switched Ethernet and shared Ethernet, both communication parties need to find the peer device connected to themselves through the MAC address. The CCN layer not only submits CCN data packets to the Ethernet layer, but also provides the identification of the next hop node. In the underlying implementation of CCN, this set of exits can be a combination of physical network port and MAC address. By physical network port and MAC

The combination of addresses can uniquely determine an adjacent device. Therefore, when forwarding the Interest packet, the CCN node can encapsulate the Interest packet into an Ethernet frame and send it according to the corresponding physical network port and MAC address entry in the FIB. The FIB table should be generated by the routing protocol, and the routing protocol completes the detection of adjacent nodes. Experimental stage Segments can also be manually configured in advance like CCNx. Similarly, the forwarding of the Data packet is based on the arrival interface of the Interest packet recorded in the PIT table. Before forwarding the Interest packet, the CCN node should record the physical network port and source MAC address it arrives in the PIT table to provide the responding Data packet Basis for forwarding.

[0104] Interest packet processing module and Data packet processing module call FIB according to CCN working mechanism

The interfaces provided by the management module, PIT management module and CS management module forward the CCN data packets to be processed in the Interest packet queue and the Data packet queue.

[0105] After receiving the Ethernet frame, the network card will determine the protocol type in the load according to the type field in the frame header, and transfer it to the corresponding protocol stack for processing. The Ethernet standard does not assign a type value to CCN. In the experimental stage, you can only temporarily use the unassigned type value as the CCN type value. Get Interest

The packet type value is 0x0601, and the Data packet type value is 0x0602. As shown in Figure 3.

[0106] The FIB management module maintains FIB entries of the CCN node. Since the routing table is manually configured through the configuration file, after the routing table is read in during the startup phase of the routing software, FIB entries will not change during operation. Therefore, the FIB management module mainly provides a search service for the Interest packet processing module. As shown in Figure 4.

[0107] The PIT management module maintains PIT entries of the CCN node. PIT is a unique structure of the CCN node, and is the core component of its normal working mechanism. When an Interest packet arrives, it is necessary to query the PIT table whether the same request has been forwarded. If the Interest packet is successfully forwarded, the content name of the request and the arrival interface must be recorded in the PIT table. When a Data packet arrives, it is necessary to query the matching content name in the PIT table, and delete the entry after forwarding. Therefore, the PIT table needs to support search, insert and delete functions. As shown in Figure 5.

[0108] The CS management module maintains the cache function of the CCN node. The content of the CS cache is that the Data packet has been forwarded. Whether it is the Interest packet or the Data packet, the match search must be performed in the CS first. When the cache is about to overflow, you need to delete the stored content according to the cache strategy to store new content. Therefore, CS needs to support operations such as find, read, insert, replace, and delete. In addition, according to the requirements of the caching strategy, some status of the accessed content must be maintained for the cached content, such as the frequency of the content being accessed, the time of the last access, and the time of the last modification.

[0109] TCP/CCN tunnel design scheme

[0110] CCN was proposed as the architecture of the future network, aiming to solve many problems faced by host-based TCP/IP

. With the continuous deepening of research in the field of CCN, a key issue currently facing is the integration of the ICN network and the existing IP network, which is of great significance for the future development and evolution of the network. To solve this problem, Proposed a CCN-based solution, mainly including TCP/CCN, based on which the prospect of TCP/CC N two-network integration is prospected, how to make the smallest possible changes to existing protocols or applications, and how to fully Taking advantage of the inherent characteristics of CCN, such as intra-network caching and multicast, is the main concern of this section.

[0111] Design Essentials

[0112] When designing the solution, it is necessary to ensure that the existing terminal and the application based on the TCP/IP protocol stack do not need to be changed, and try not to change or change the existing CCN design principles as little as possible. In order to ensure the sex B after protocol conversion and enhance usability, the following key indicators cannot be ignored in the design.

[0113] 1) The length of the Interest package name. An interest packet name that is too long increases the router's overhead in parsing and matching, and reduces network performance; however, if the name is too short, it cannot carry enough information.

[0114] 2) The length of the Data package name. To control the name and content of data packets to an appropriate range, a data packet with an excessively long name will inevitably lead to a reduction in the content carried, and more data packets need to be sent to reduce network efficiency.

[0115] 3) The number of round trips. The number of round trips for a data exchange should be as small as possible.

[0116] 4) Data fragmentation and reliable transmission. When the transmission data block exceeds the MTU limit, the fragmentation operation needs to be taken. This requires that the fragments of the same data block have a naming relationship (such as increasing the sequence number).

[0117] 5) In-network caching is one of the significant features of CCN, and making full use of caching is conducive to improving network performance.

[0118] TCP/CCN conversion ideas

[0119] Another conversion idea of combining CCN with an IP network is to start with TCP. TCP is the most widely used protocol in the transport layer of existing IP networks. A large number of application layer protocols are based on it. Therefore, the protocol conversion between TCP and CCN has a wider practical significance.

[0120] In the conversion process between TCP and CCN, the difficulties faced mainly come from two aspects: First, TCP is an end-to-end protocol, through the IP address and port number for one-to-one communication, which is based on content with CCN There is a contradiction in the basic concept of the second. In CCN, the communication is initiated by the user, that is, the user sends an interest packet, and the server responds with the data packet. This, in the eyes of the user, is a "pull" of the required data. In TCP, only the sender sends data, and the receiver replies with a confirmation message. In other words, this is a "push" process, and the two are essentially semantically different.

[0121] In addition to the basic connection communication function, the TCP protocol also has mechanisms such as congestion control and flow control. As a reliable transport layer protocol, through the retransmission mechanism, TCP can ensure end-to-end reliability Transmission, and these functions are not involved in CCN, how to retain as much as possible in the conversion These mechanisms cannot be ignored in the design. As shown in Figure 6.

[0122] Design Scheme of TCP/CCN

[0123] The purpose of the design is to enable the two TCP terminals to communicate through the middle CCN network, and a pair of conversion nodes need to be set at the boundary between the IP network and the CCN network. , Connect to the sending end and receiving end of TCP respectively. Protocol conversion and package encapsulation are carried out in the agent, each agent has a name as a routing prefix in the CCN network, so that the package in the CCN can be successfully passed to the designated agent for the next processing, the name of the agent There is a mapping relationship with its IP address.

[0124] 1) Transmission process

[0125] Since the data transmission in the CCN network adopts the “pull” mode, each data packet is transmitted to correspond to an interest packet request. Therefore, the receiving agent is required to send the interest packet request data before the sending agent can send out the corresponding data packet. In order to let the receiving agent know that there is content to be transferred, it is necessary for the sending agent to send an additional interest packet to inform the receiving agent. Specifically, when the TCP fragment arrives at the sending agent, it needs to convert the data to be transmitted into the form of a CCN data packet, and at the same time generate an interest packet to inform the receiving agent that there is data to be fetched, this interest packet is constructed using the TCP/IP header, The name of the interest package is similar to the following form: /revproxy-prefix/TCP-IP-headers/nonce. Among them, the first item is the routing prefix of the receiving agent, which is used to route to the receiving agent, the second item is the TCP/IP header, which is used to provide the necessary information to the receiving agent to construct the interest packet for pulling data, and the final random The number is used to ensure uniqueness and prevent AC K messages from being merged by CCN nodes due to the same name.

[0126] At the same time, the newly constructed data packet is placed in the sending proxy buffer and waiting for the recipient to fetch. The naming of the data packet follows the following rules: /forwardproxy-prefix/TCP-tuple/TCP sequence number/number, where the first item It is the name of the sending agent, which is used for routing. The second item includes the sender and receiver sockets, followed by the sequence number of this TCP segment. The last digit is to prevent the naming conflict caused by the TCP sequence number running out of cycles.

[0127] When the interest packet arrives at the receiving agent, the agent knows that there is data to be fetched at the sending end, and immediately sends the interest packet to request the data. According to the matching principle in CCN, the name of the interest packet here is the same as the previous data packet After the data packet arrives at the receiving agent, it performs the decapsulation operation, transmits the TCP fragment encapsulated in the data packet to the TCP receiving end through the IP network, and finally sends back an ACK response, which realizes the transmission of the TCP stream through the CCN the process of. As shown in Figure 7. [0128] 2) TCP connection establishment

[0129] Connection establishment: The TCP three-way handshake is mapped to the equivalent of three interest exchanges, and both agents undergo a series of initializations. It is beneficial to use only Interests during the TCP setup phase, because in order to transfer actual TCP data, corresponding Data messages can be saved. As shown in Figure 8.

[0130] 3) TCP connection is disconnected

[0131] Disconnection: Similarly, the TCP four wave process is equivalent to four interest packet exchanges in TCP/CCN, and both agents experience a series of termination states. It is worth noting that for TCP connection establishment/disassembly, the interest packet exchange is the same.

[0132] Another object of the present invention is to provide a method and system for transmitting IP data packets using a content center network as a tunnel, characterized in that the system includes

[0133] A dividing module for dividing the CCN network into an application layer, a content layer, a data link layer and a physical layer and mapping content names in the CCN network to MAC address queries;

[0134] a building module for constructing a new CCN network according to the link layer transmission technology in the layered CCN network to construct FIB entries, PIT entries, CS caches, and FWD entries;

[0135] Build a network module for deploying a pair of relay nodes with dual stack functions at the boundary of the IP network and the new CCN network to connect to the TCP sender and receiver respectively to build a TCP/CCN network;

[0136] A data exchange module, configured to complete data packet transmission through multiple interest packet exchanges on IP data in a TCP/CCN network.

[0137] The FIB entry is generated by a routing protocol, the FIB

The entry does not change during operation, the FIB entry provides a search service for the Interest packet processing module

[0138] The arrival interface of the Interest packet recorded in the PIT entry, before forwarding the Interest packet, the CCN node should record the physical network port and source MAC address it arrives in the PIT entry to provide a forwarding basis for the responding Data packet , PIT table items need to support search, insert and delete functions.

[0139] The CS cache supports operations of searching, reading, inserting, replacing, and deleting. When the Interest package or the Data package arrives, the CS cache is first searched for matching, and the accessed content is maintained according to the cache strategy. status.

[0140] The data transmission process in the data exchange module includes the following units [0141] an interest packet sending unit, which is used for the sending agent to convert the data to be transmitted into the form of a CCN data packet after receiving the TCP segment and generate an interest packet to inform the receiving agent that there is data to be fetched;

[0142] sending a request data packet unit, for the receiving end to receive the interest packet received by the agent and send the request data interest packet to the receiving agent;

[0143] The decapsulation transmission unit is used to receive the request data interest packet to decapsulate the encapsulated data packet, transmit the encapsulated TCP segment to the TCP receiving end through the IP network, and send back an ACK response.

[0144] The TCP/CCN network establishment connection in the data exchange module includes the following units

[0145] The first SYN unit for the sending agent to receive the SYN sent by the sending end;

[0146] The first SYN marked interest packet sending unit is used by the receiving agent to send the interest packet with the SYN logo to the receiving agent via the CCN network and receive it;

[0147] Send SYN and ACK unit, for the receiving end to receive the receiving agent to send SYN and send SYN+ACK to the receiving agent;

[0148] transmitting a SYN and ACK identification interest packet unit, used by the receiving agent to send the SYN and ACK identification interest packet to the sending agent via the CCN network;

[0149] The transmission band sending ACK unit is used for the sending end to receive the SYN and ACK sent by the sending agent and generate a sending ACK transmission to the sending agent;

[0150] The transmission belt sends an ACK identification interest packet unit for the sending agent to send the interest packet with the sent ACK identification to the receiving agent via the CCN network;

[0151] The receiving agent with the ACK identification and sending interest packet unit receiving agent sends the interest packet with the sending ACK identification to the receiving end.

[0152] The disconnection of the TCP/CCN network connection in the data exchange module includes the following units

[0153] a first receiving and forwarding unit, configured to send an agent to receive the FIN sent by the sending end, and forward the interest packet with the FIN identification of the sending end to the receiving agent via the CCN network;

[0154] a first transmission unit, configured to receive an agent to transmit the interest packet with the FIN identification of the sending end to the receiving end;

[0155] The second receiving and forwarding unit is used for the receiving agent to receive the ACK sent by the receiving end, and forward the interest packet with the ACK identification of the receiving end to the sending agent via the CCN network;

[0156] a second transmission unit, configured to send the agent to transmit the interest packet with the ACK identifier of the receiving end to the sending end;

[0157] A third receiving and forwarding unit, configured to receive the FIN sent by the receiving agent and forward the CCN network Interest packets with FIN identification at the receiving end are sent to the sending agent;

[0158] a third transmission unit, which is used by the sending agent to transmit the interest packet with the FIN identification of the receiving end to the sending end;

[0159] a fourth receiving and forwarding unit, which is used by the sending agent to receive the ACK sent by the sending end, and forward the interest packet with the ACK identifier of the sending end to the receiving agent via the CCN network;

[0160] A fourth transmission unit is configured to receive an agent to transmit the interest packet with the ACK identifier of the sending end to the receiving end.

[0161] The current network applications are all built on IP, so any deployed CCN also needs to be able to coexist with IP. Compared with existing work, CCN uses TCP, UDP, or IP as the tunnel during deployment. This usually requires manual compression of the tunnel endpoints. When a new CCN needs to be deployed, the tunnel needs to be changed manually. In addition, these point-to-point tunnels limit CCN's ability to use the bottom layer to broadcast media. In order to make full use of content-centric communication and simplify the deployment process, we proposed a solution to deploy CCN nodes directly via Ethernet.

[0162] The new network protocol stack proposed by the present invention maps the content names in the CCN network to MAC addresses, and then reuses the existing link layer transmission technology to realize data transmission, and builds on the Ethernet data link layer. A tunnel of a CCN network. At the same time, a router with dual stack function is deployed at the edge of the IP network and the CCN network to realize the connection between the IP network and the CCN network based on Ethernet. This solution of incremental deployment on the basis of the existing network infrastructure can be very good due to the transition problem from the existing IP network to the future network, and can maximize the reuse of the existing IP network infrastructure At the same time, it provides smooth support for the connection between the IP network and the CCN network.

[0163] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modification, equivalent replacement and improvement made within the spirit and principle of the present invention should be included in this Within the scope of protection of the invention.

Claims

[Claim 1] A method for transmitting IP data packets using a content-centric network as a tunnel, characterized in that the method includes the following steps:

51. The CCN network is divided into an application layer, a content layer, a data link layer, and a physical layer, and the content names in the C CN network are mapped to MAC address queries;

52. Build FIB entries, PIT entries and CS cache entries in the forwarding daemon FW D according to the link layer transmission technology in the layered CCN network to form a new CCN network;

53. Deploy a pair of transfer nodes with dual stack functions at the boundary of the IP network and the new CCN network to connect to the TCP sender and receiver respectively to build a TCP/CCN network;

54. In a TCP/CCN network, IP data packets are transmitted through multiple CCN node interest packet exchanges.

[Claim 2] The method for transmitting IP data packets using a content-centric network as a tunnel according to claim 1, wherein the FIB entry is generated by a routing protocol, and the FIB entry will not change during operation The FIB entry provides a search service for the Interest packet processing module.

[Claim 3] The method for transmitting IP data packets using a content-centric network as a tunnel according to claim 2, characterized in that, before the arrival packet of the Interest packet recorded in the PIT entry, the CCN node needs to forward the Interest packet, Record the physical network port and source MAC address it arrives in the PIT entry to provide the basis for forwarding the responding Data packet. The PIT entry must support search, insert, and delete functions.

[Claim 4] The method for transmitting IP data packets using a content-centric network as a tunnel according to claim 3, characterized in that the CS cache supports operations of searching, reading, inserting, replacing and deleting, in the Interest package or When the data package arrives, it is necessary to perform a matching search in the CS cache, and maintain the accessed state of the cached content according to the cache strategy.

[Claim 5] The method for transmitting IP data packets using a content-centric network as a tunnel according to claim 4, wherein the data transmission process in step S4 includes the following steps:

5411. After receiving the TCP segment, the sending agent converts the data to be transmitted into the form of a CCN data packet and generates an interest packet to inform the receiving agent that there is data to be fetched;

5412: After receiving the interest packet, the receiving agent sends the request data interest packet to the receiving agent; S413: The receiving agent receives the request data interest packet, decapsulates the encapsulated data packet, transmits the encapsulated TCP segment to the TCP receiving end through the IP network, and sends back an ACK response.

[Claim 6] The method for transmitting IP data packets using a content-centric network as a tunnel according to claim 5, characterized in that, in step 84, the network establishment connection includes the following steps:

5421, the sending agent receives the SYN sent by the sending end;

5422. The receiving agent sends the interest packet with the SYN logo to the receiving agent via the CCN network and receives it;

5423. The receiving end receives the receiving agent and sends the SYN and sends SYN+ACK to the receiving agent

5424. The receiving agent sends the interest packet with SYN and ACK signs to the sending agent via the CCN network;

5425. The sending end receives the SYN and ACK sent by the sending agent and generates a sending ACK to transmit to the sending agent;

5426. The sending agent sends the interest packet with the ACK mark to the receiving agent via the CCN network;

5427. The receiving agent sends the interest packet with the ACK mark to the receiving end.

[Claim 7] The method for transmitting IP data packets by using the content-centric network as a tunnel according to claim 6, characterized in that the disconnection of the TCP/CCN network connection in the step S4 includes the following steps:

5431. The sending agent receives the FIN sent by the sending end, and forwards the interest packet with the FIN identification of the sending end to the receiving agent via the CCN network;

5432. The receiving agent transmits the interest packet with the FIN identifier of the sending end to the receiving end;

5433. The receiving agent receives the ACK sent by the receiving end, and forwards the interest packet with the ACK identification of the receiving end to the sending agent via the CCN network;

5434. The sending agent transmits the interest packet with the ACK identifier of the receiving end to the sending end;

5435. The receiving agent receives the FIN sent by the receiving end, and forwards the interest packet with the FIN identification of the receiving end to the sending agent on the CCN network;

5436. The sending agent transmits the interest packet with the FIN identification of the receiving end to the sending end;

5437. The sending agent receives the ACK sent by the sending end, and forwards the sent message via the CCN network. Send the interest packet identified by the ACK to the receiving agent;

S438. The receiving agent transmits the interest packet with the ACK identifier of the sending end to the receiving end.

[Claim 8] A system for transmitting IP data packets using a content-centric network as a tunnel, characterized in that the system includes

The dividing module is used to divide the CCN network into an application layer, a content layer, a data link layer and a physical layer and map the content names in the CCN network to MAC address queries;

Construction module, used to construct FIB entries, PIT entries, and CS cache entries in F WD in the layered new CCN network according to the link layer transmission technology; form a new CCN network; build a network module, used in IP A pair of transit nodes with dual stack functions are deployed at the border of the network and the new CCN network to connect to the TCP sender and receiver of the IP network to form a TCP/CCN network;

The data exchange module is used to complete the data packet transmission of IP data through multiple interest packet exchanges in the TCP/CCN network.

[Claim 9] The system for tunneling IP data packets using a content-centric network as claimed in claim 8, wherein the FIB entry is generated by a routing protocol, and the FIB entry will not change during operation The FIB entry provides a search service for the Interest packet processing module.

[Claim 10] The system for tunneling IP data packets using the content-centric network as claimed in claim 9, characterized in that: the arrival interface of the Interest packet recorded in the PIT entry, before the CCN node forwards the Interest packet, Record the physical network port and source MAC address it arrives in the PIT entry to provide the basis for forwarding the responding Data packet. The PIT entry must support search, insert, and delete functions.

[Claim 11] The system for transmitting IP data packets using a content-centric network as a tunnel according to claim 10, characterized in that the CS cache supports operations of searching, reading, inserting, replacing and deleting, in the Interest package or When the data package arrives, it is necessary to perform a matching search in the CS cache, and maintain the accessed state of the cached content according to the cache strategy.

[Claim 12] The system for transmitting IP data packets using a content-centric network as a tunnel according to claim 11, characterized in that the data transmission process in the data exchange module includes the following unit for sending an interest packet unit for sending an agent After receiving TCP fragments, convert the data to be transmitted It is in the form of a CCN data packet and generates an interest packet to inform the receiving agent that there is data to be fetched; Send request data packet unit is used by the receiving end to receive the interest packet and send the request data interest packet to the receiving agent;

The decapsulation transmission unit is used for the receiving agent to receive the request data interest packet to decapsulate the encapsulated data packet, transmit the encapsulated TCP segment to the TCP receiving end through the IP network and send back an ACK response.

[Claim 13] The method for tunneling IP data packets using the content-centric network as claimed in claim 12, wherein the TCP/CCN network establishment connection in the data exchange module includes the following units

The first SYN unit is used for the sending agent to receive the SYN sent by the sending end;

The first SYN marked interest packet sending unit is used by the receiving agent to send the interest packet with the SYN logo to the receiving agent via the CCN network and receive it;

Sending SYN and ACK units, used for the receiving end to receive and receive the receiving agent to send SYN concurrent S YN+ACK to the receiving agent;

Transmit the SYN and ACK identification interest packet unit, used by the receiving agent to send the SYN and ACK identification interest packet to the sending agent via the CCN network;

The transmitting end sends an ACK unit, which is used by the sending end to receive the SYN and A CK sent by the sending agent and generate a sending ACK transmission to the sending agent;

The transmission end sends an ACK to identify the interest packet unit, which is used by the sending agent to send the interest packet with the ACK identification to the receiving agent via the CCN network;

The receiving end sends an ACK to mark the interest packet unit. The receiving agent sends the interesting packet with the sending ACK mark to the receiving end.

[Claim 14] The method for tunneling IP data packets using the content-centric network as claimed in claim 13, wherein the disconnection of the TCP/CCN network connection in the data exchange module includes the following units

The first receiving and forwarding unit is used by the sending agent to receive the FIN sent by the sending end, and forwards the interest packet with the FIN identification of the sending end to the receiving agent via the CCN network;

A first transmission unit, used for the receiving agent to transmit the interest packet with the FIN identification of the sending end to the receiving end; The second receiving and forwarding unit is used for the receiving agent to receive the ACK sent by the receiving end, and forward the interest packet with the ACK identification of the receiving end to the sending agent via the CC N network;

A second transmission unit, used by the sending agent to transmit the interest packet with the ACK identification of the receiving end to the sending end;

The third receiving and forwarding unit is used for the receiving agent to receive the FIN sent by the receiving end, and forward the interest packet with the FIN identification of the receiving end to the sending agent in the CCN network;

The third transmission unit is used by the sending agent to transmit the interest packet with the FIN identification of the receiving end to the sending end;

The fourth receiving and forwarding unit is used for the sending agent to receive the ACK sent by the sending end, and forward the interest packet with the sending end ACK identifier to the receiving agent via the CC N network;

The fourth transmission unit is used for the receiving agent to transmit the interest packet with the ACK identifier of the sending end to the receiving end.