DE102008032748A1 - Peer-to-peer network operating method, involves storing routing-table with network addresses of peer-devices in peer-to-peer network, and transmitting message directly from one of peer device to another peer device - Google Patents

Abstract

The method involves assigning network address (IP1-IP5) to peer devices (P1-P5) in a communications network. A routing-table is stored with the network addresses of the peer-devices in the peer-to-peer network. A message is transmitted directly from one of the peer device to another peer device without routing or hopping over other peer devices, where the routing table comprises peer-identifications (NID1-NID5), network address and a time specification for the peer-devices in a peer-to-peer network. Independent claims are also included for the following: (1) a computer -program product for operating a peer-to-peer network (2) a peer-to-peer network comprising peer devices.

Description

The The present invention relates to a method for operating a Peer-to-peer network, a peer-to-peer network, and a corresponding peer-to-peer network A computer program product.

With Peer-to-peer systems make it possible to use a variety of Devices, referred to below as peer devices become compatible with each other without centralized facilities such as servers network. Here are certain services, which in usual Client-server architectures from the respective central unit, the server is taken over by the peer facilities itself be provided. One functionality is the Address resolution, d. H. the for the contact necessary implementation of known data for a particular peer the user to the network address of his device or his peer facility. Known data can be z. As the user name, a telephone number or other peer devices characterizing Be designations. Often the internet is considered subordinate Communication network with the well-known Internet protocol TCP / IP so the network address is usually the IP address and the port of the peer. The following is the name Peer and peer devices, but they are also terms like network element, component, communication terminal, subscriber, Instance or station familiar.

The Communication between peers takes place via the protocol the subordinate communication network, which for example the internet is. The actual peer-to-peer network will then go through a group of peers formed, each with a node ID or Node address within the peer-to-peer (P2P) network. One also speaks of the peer-to-peer network as an overlay network. A data connection between two peers of a P2P network requires first the determination of the network address of the requested peer from the Node address known to the requesting peer. In so-called hybrid P2P networks, a server keeps a central directory the peers involved in the P2P network in the form of their node address and corresponding network address. File sharing platforms such as Napster or iMesh, Audio Galaxy or SongSpy are based on a P2P network with a corresponding central Directory service. The disadvantage here is that in case of failure of the central Directory service no longer communication links can be built. Furthermore, the connection is established through the intermediary of the address request at the central server slowed down and therefore slow.

Around the dependency on a server with a central address directory It is possible to bypass so-called decentralized P2P networks to implement. It is not a central server or an excellent one Peer, intended for a directory service. An inquiring one Peer then dynamically locates further peers of the P2P network and communicates with them to exchange data and information. The address resolution, ie the discovery of the network address of the node address in the P2P network requested peers, is done dynamically via a routing protocol.

One possibility is, for example, the use of a distributed hash table (DHT = Distributed Hash Table). In this case, the table which assigns each peer or each node address a corresponding network address in the communication network used is distributed to all involved peers in the P2P network. In the case of a ring-organized logical arrangement of the peers or the node addresses, the peers can, for example, store a predefined number of adjacent peers or node addresses and their network addresses in a local assignment or hash table. The node address space has a metric defining distances between peers and node addresses. A suitable algorithm for address resolution in a ring-organized decentralized P2P network is z. For example, the Chord algorithm, which in Ion Stoica, Robert Morris, David Karger, M. Frans Kaashoek, Hari Balakrishnan: "CHORD: A Scalable Peer-to-Peer Lookup Service for Internet Applications, MIT-LCS-TR-819 is described.

The For example, mapping a node address or node ID (node ID) by applying a hash function to a user name of the be determined peers. Analog can also Search terms, such as file names of a hash function which yields a hash value. Every peer is one Range of hash values assigned to e.g. B. again arranged in ascending order are. The first hash value of the associated peer Area corresponds to z. B. the node address of the relevant Peers. This determines, for example, which data is under the hashed file name are available at a peer.

A search for data or participants or peers is carried out by the requesting or searching peer the hash value of the given keyword, such as file name, username or z. B. telephone number. In order to find the network address of the node ID to be searched for by the hash, the requesting peer sends a search request to a peer, with its node address and associated network address in a list of known peers, for example a neighbor list and / or finger list, of the requesting peer. If the requested peer is responsible for the searched hash value, it sends the requested data to the requesting peer over the network.

If the first requested peer is not responsible for the hash value is, he answers with the address of a peer from his peer list, whose node ID is more similar to the searched hash value as its own node address. Whether the own node ID with the similar to the searched node ID or the searched hash value is determined by the metric used by the node address space. The first requested peer thus sends the requesting peer one Node ID and IP address closer to the searched hash value comes. The requesting peer can now send a second query to the Send peer with the closer node address. This method is continued until a peer is found for is responsible for the hash value and provide the searched data can. It therefore results for the message exchange between the peers usually a multiple hopping. The message is transmitted through multiple peer devices on the network routed to the respective target spear.

at This decentralized structure of the P2P network, the participating peers be organized in a ring structure, the resulting from the ordered periodically continued list of node addresses. In principle, other structures are possible, for example a tree structure. For example, P2P networks are used to exchange files in file sharing networks. An address resolution in terms of the network address in the network used but also particularly important in so-called VOIP transmissions, d. H. Voice over the Internet (VOIP = voice over IP). For example, a P2P network is for voice transmission known as "Skype". The communication software Skype requires centralized delivery of network address information the participating peers. Participants of this network can exchange voice data with each other and thus via the Internet calls.

at all the above methods have the problem that messages, which are sent from one peer to another over several existing peers must be routed. Thereby the actual information exchange is slowed down and slow. In particular, applications that require real-time processing, can not be solved by conventional peer-to-peer protocols realize.

It is therefore an object of the present invention, an improved To provide a method of operating a peer-to-peer network.

It Therefore, a method for operating a P2P network with Several peer devices are proposed, each peer device each assigned a network address in a communication network becomes. Furthermore, each peer device becomes a routing table with at least the network addresses of the other peer devices stored in the P2P network.

It In addition, a P2P network with several peer devices is proposed. which each have a network address in a communication network is assigned. Each peer device stores a routing table with at least the network addresses of the other peer devices in the P2P network.

A Routing table enables the sending of messages between peer devices in the P2P network without further routing mechanisms for example via other peer devices. news are therefore sent directly from one peer to another, which z. For example, in applications that should be done in real time, a significant Acceleration of data exchange over conventional Routing procedure creates. All peer facilities can each store a routing table.

The routing table preferably comprises a peer identification for each peer device present in the P2P network, such as e.g. As a node address, the network address and a time. The time specification provides information about the timeliness of the routing table, z. For example, when a change in the subscriber peers in the peer-to-peer network has occurred. It is possible to assemble the routing table from the information that is exchanged anyway to stabilize the network between the peer devices. Stabilization messages, for example, are exchanged when peer devices join the network or log off or fail. The resulting information can be sent by a participating peer device immediately to all other peer devices in the P2P network. This means that every P2P device in the P2P network has all the necessary routing information so that the exchange of messages or information can be carried out quickly.

At the Sending a message from a first peer device to a second peer device in the communication network, for example can be the Internet, the first peer device reads the network address the second peer device from that of the first peer device saved routing table.

Preferably becomes a message for all peer facilities from a first peer device to a second peer device transmitted directly without routing or hopping via another peer device.

at A variant of the method is used in addition or removal a peer device to or from the P2P network the network address the adjoining or withdrawing peer device in the P2P network published. Publishing is the distributed one Storing information in the P2P network, with appropriate Then enter information for a resource everyone involved in changing the network composition Peers are accessible. The peer facilities can over a subscribe mechanism that many P2P network protocols hold, Record or monitor current changes.

It may interfere with the addition or removal of a peer device to or from the P2P network also multicast to update the done by the peer devices stored routing tables. It is therefore part of the process of operating a P2P network ensures that even with a change the composition of the P2P network the routing tables at all Peers are always up to date.

One appropriate P2P network can be used in particular as an embedded network be formed, the peer facilities a limited Include number. In particular, the network preferably has less as 257 peer facilities, enabling timely distribution and updating as well as efficiently storing the routing table at each peer can be. The peer devices can be used as peer-client software z. B. implemented for program-controlled devices such as PCs become.

In a variant is the P2P network with a distributed hash table and in particular with a Chord algorithm or a Kademlia algorithm operated for resource provisioning in the P2P network. Deviating from the usual algorithms, however, the Routing table provided on each peer device.

The The invention further relates to a computer program product comprising the Conducting a corresponding procedure on a program-controllable computer device causes. As a program-controlled computer device For example, a PC or even a mobile device is an option. on the appropriate (client) software is installed. The computer program product For example, in the manner of a data carrier such as Example USB flash drive, floppy disk, CD-ROM, DVD can be implemented or on a server device as a downloadable program file be implemented.

Further advantageous embodiments of the invention are the subject of the dependent claims and the embodiments described below. In the following, the invention will be described with reference to exemplary implementations explained in more detail with reference to the accompanying figures. It shows:

1 : a schematic representation of a peer-to-peer network with distributed hash table;

2 : an exemplary illustration of a peer-to-peer network with peer devices having a routing table;

3 : an exemplary representation of processes in a peer-to-peer network on the addition of a peer; and

4 : an exemplary representation of processes in a peer-to-peer network in the event of a peer failure.

In the figures, identical or functionally identical elements are provided with the same reference numerals unless otherwise stated.

To explain the general problem in address resolution in peer-to-peer networks is in the 1 exemplified a ring-organized P2P network. There are provided peer devices P1-P8, which are designed, for example, as a computer connected to the Internet with an installed P2P software. Each peer therefore has an IP address IP1-IP8 identifying it on the Internet and a node address NID1-NID8 identifying it as a peer in the P2P network P2P1. In the following, the mode of operation of the Chord algorithm for address resolution will be explained by way of example. However, other P2P protocols are also available for distributed P2P networks.

The Node address of a peer results, for example, by application a suitable hash function in the name of the peer. The name may be, for example, a user name or a telephone number. The hash value of a corresponding search term, for example one Telephone number, is assigned to a node ID or a node address. It can also have multiple hash values of a node address be assigned.

For example, the peer P1 may be assigned a node address NID1 = 003, where the value NID1 = 003 indicates the beginning of a range of hash values for which the peer P1 is responsible. For example, in a P2P network that uses 10-bit hashes, you can map ranges of hashes to the peers, as shown in the following table. For 10-bit hash values, for example, 1024 peers are possible in the P2P network. Peer node address hash values P1 NID1 = 003 H = 003 ... 123 P2 NID2 = 124 H = 124 ... 203 P3 NID3 = 204 H = 204 ... 311 P4 NID4 = 312 H = 312 ... 433 P5 NID5 = 434 H = 434 ... 522 P6 NID6 = 523 H = 523 ... 689 P7 NID7 = 690 H = 690 ... 814 P8 NID8 = 815 H = 815 ... 002

Each Peer is thus assigned a node address with a specific value and a range of hash values generated from search terms H = hash (search term).

The Table thus represents the complete table of the P2P network This is not centrally provided by a server, but stored on the individual peers P1-P8 stored. Each peer knows the assigned hash values of its neighbors, for example the nearest neighbor.

The peer P3 has stored the information that for hash values 124-203 the peer P2 with node address NID2 = 124 is responsible. The peer P3 also knows its own responsibility for the hash values 204-311 and the responsibility of the neighboring peer P4 with the node address NID4 = 312 for the hash values 312-434. Generally, each peer has a partial hash table with the assignment of hash values of its peers adjacent to the node address space and, if appropriate, the assignment of the hash values of one or more finger peers, eg. In the case of the peer P3, the assignment of the peer P7 to the node address NID7 = 690 for the hash values 690-814. A corresponding partial hash table PHT is in the 1 shown.

If now starting from the peer P2 a query or file query for a search term that hashed the hash value (search term) = 530 returns, the peer P2 sends a query F1 to the peer P3 stating its own network address IP2 and the searched hash value 530. The peer P3 is selected, since in the partial hash table PHT2 of the peer P2 the hash value 530 closer to the area of responsibility of peer P3 with hash values between 204 and 311, as the other in the sub-hash table listed Peer P1 with area of responsibility between H = 003 and 123. Therefore, a query will always be to those Peer sent in its own sub-hash table, its node address in the node address space closest to the hash value of the search term or the destination node address.

The peer P3 then examines its partial hash table PHT3 and determines the peer P7 as the peer whose jurisdiction or hashed values match the searched hash value 530 am Next is and sends a corresponding second query F2. The peer P7 determines in its associated partial hash table PHT7 the peer P6 with the node address 523 as peer responsible for the hash value 530 and sends this information to the originally requesting peer P2 whose network address IP2 the search requests F1, F2 assigned. Alternatively, if peer P2 has sent a data query of the search term having hash value 530, peer P7 could send peer P6 the data query request from peer P2 or its network address IP2 in a message F3 '. The destination peer P6 then transmits directly to the requesting peer P2 or its IP address IP2 the data designated by the hash value 530 via a data connection F4 in the communication network or Internet. Thus, a corresponding P2P protocol enabled the address resolution of searched data, for example from the peer P2, which has no information about the storage location of this data in the P2P network, since the partial flash table PHT2 assigned to the peer P2 does not include this node address range.

In the 2 an exemplary representation for another peer-to-peer network is shown. For example, the peer-to-peer network P2P2 uses the Internet IN as the underlying network. By way of example, five peer devices P1-P5 are shown, which are set up, for example, using a modified Chord Protocol algorithm. Contrary to a complex address resolution and the elicitation of network addresses for the peer devices P1-P5, the operation of the peer devices P1-P5 present in the peer-to-peer network P2P2 provides in each case a stored routing table R1-R5. Ideally, the routing tables R1-R5 in the peer devices P1-P5 match in content or they are always updated in a timely manner when the composition of the peer-to-peer network P2P2 changes.

In the respective routing table R1-R5 is the peer identification or node address ID1-ID5 for each peer device P1-P5 and the associated network address IP1-IP5, which is used for message or information exchange necessary in the network IN. Since each of the peer devices P1-P5 via has the routing table P1-P5 in stored form, is it possible without additional routing operations Exchange messages. For example, a memory area or a dedicated memory for the routing table provided become. For example, when sending a message from the Peer device P1 to the peer device P5 can under coordination a correspondingly modified peer-to-peer protocol algorithm the peer device P1 from its present routing list R1 read out the network address of peer P5. The shipment of the message F1 then takes place directly using the network address IP5 for the peer device P5 with the node address NID5. There is no hopping or further routing with the message F1, which could delay the exchange of information or messages. Also, the response message F2 from the peer device P5 to the Peer setup P1 will hopping or routing without further ado other entities in the P2P2 peer-to-peer network. The peer device P5 reads from its complete routing table R5 outputs the network address of the peer P1 IP1 and sends it directly under the protocol for the underlaying Internet IN the message F2. Especially for real-time applications by providing routing tables at all peer devices implement an implementation in peer-to-peer networks. In In the past this was especially because of the complicated Routing method hardly possible.

The proposed method or implementation in a peer-to-peer network, as described in the 2 is particularly advantageous if only a clear number of peer devices that provide their resources with relatively high reliability are used. Embedded peer-to-peer networks with implementations of up to 256 peers are particularly efficient. For example, in Voice-over-IP-based corporate telephone networks, VOIP phones can be thought of as peer devices. The direct routing without intermediate hops then results in a particularly fast connection setup over conventional methods. As a result, the acceptance of corresponding VOIP-based telephone retail networks as peer-to-peer networks can be increased. Although the routing table is maintained in each peer, additional functions, such as answering machine functionality or data or resource storage, may be distributed based on previously described hash table mechanisms. Although the efficiency of a corresponding peer-to-peer network, as described in the 2 is indicated, especially given stable peer-to-peer networks, ie, if only occasionally a peer fails or another added to the network, even with a change in the peer-to-peer network composition, the routing table on easy way to be updated.

In the 3 an example of operations in a peer-to-peer network P2P3 is shown when another additional peer device is added to a peer-to-peer network organized, for example, in the manner of a chord-ring. In this case, peer devices P1-P8 are shown by way of example, wherein the numbers drawn in circles z. B. correspond to the respective node addresses. In the illustrated Sze nario adds another peer device P9 to the network. The peer P9 logs in with its network address to its future successor (in the chord ring) in the network and sends a message to all present in the network peer facilities.

In the example of 3 the peer P9 logs on to the peer P8 which has the next lowest node address ( 54 ) opposite the node address ( 68 ) of the peer P9. Via a multicast or individual messages DIS, the adjoining peer P9 transfers its node ID and the respective network address to all other peer devices P1-P8. This makes it possible to update the routing tables in the individual peer devices P1-P8. The respective peer devices P1-P8 send an acknowledgment message AK to the peer P9. For example, the peer P9 itself obtains the original routing table from the peer device P8 before publishing its own address data in the peer-to-peer network P2P3. After the confirmation messages AK, there is also a complete and updated routing table on the peer P9. Subsequently, in the operation of the peer-to-peer network P2P3 a message exchange, such as in the 2 is indicated, done directly and without further routing.

additional neighboring peer devices can mutually stabilize messages according to, for example, the Chord Protocol. The address information is transmitted cyclically in these stabilization messages. The respective neighboring peer devices monitor thereby the regular arrival of the stabilization messages. If a message for a peer over fails for a predetermined period of time, this peer is considered off-line or failed to consider what the originally adjacent Peer facilities to update the routing table to the can report to other peer organizations.

For example, in the 4 a scenario is suggested in which the peer device P9 fails or is logically disconnected from an original chord ring of the peer device P1-P9. Thus, the peer device P9 removing from the peer-to-peer network P2P3 sends a respective outage message EX to all other peer devices. They can then update their routing table. To close the chord ring, which passes through the adjacent peer devices P8 and P1 (P8 has as node address ( 18 ), P9 ( 32 ) and P1 ( 42 )) close the ring. The peer device P8 which precedes in the chord ring sends a joint message JO to the peer device P1, thereby creating a closed peer-to-peer network again.

at an uncontrolled failure of a peer device is the Stabilizing and restoring an exemplary chord ring in the peer-to-peer network when stabilization messages fail. Such heartbeat or heartbeat messages that every peer transmitted to his neighbor peer facilities, the show Activity of the peer device. Falls one Peer device, d. H. there will be no heartbeat news is sent according to the method of operation of the peer-to-peer network, the routing table on all the rest Peer facilities updated, for example, through direct messaging can be done. The remaining properties of a peer-to-peer network, for example, when publishing or deploying resources, z. B. in the context of a known peer-to-peer protocol remain unaffected. However, the message exchange can be clear faster and more efficient, always without routing algorithms the direct network address of all peer devices is known.

The Implementation of the method or the mentioned method steps can be implemented by the peer devices. It is clear to those skilled in which parts of the process which device or, for example, a subroutine of a corresponding computer program assigned. In this respect, the functional blocks in the figures also as program modules or routines to understand or as decidedly furnished facilities, which for Implementation of the respective function during the procedure serve.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited non-patent literature

• Ion Stoica, Robert Morris, David Karger, M. Frans Kaashoek, Hari Balakrishnan: "CHORD: A Scalable Peer-to-Peer Lookup Service for Internet Applications, MIT-LCS-TR-819 [0005]

Claims (12)

Method for operating a peer-to-peer network (P2P2) with several peer devices (P1-P5), which each one network address (IP1-IP5) in a communication network (IN), where each peer device (P1-P5) a routing table (R) with at least the network addresses (IP1-IP5) the remaining peer devices (P1-P5) in the Peer-to-peer network (P2P2) is stored. The method of claim 1, wherein a first peer device (P1) sending a message (R1) to a second peer device (P5) via the communication network (IN) the network address (IP5) of the second peer device (P5) from that of the first peer device (P1) stored routing table (R1). The method of claim 1 or 2, wherein for all peer devices (P1-P5) have a respective message (R1, R2) from a first peer device (P1) to a second peer device (P5) directly without routing or hopping over another Peer device (P2-P4). Method according to one of claims 1-3, wherein the routing table (R1-R5) is to each in the peer-to-peer network (P2P2) present peer device (P1-P5) a respective Peer identification (NID1-NID5), the network address (IP1-IP5) and a time indication. Method according to one of claims 1-4, wherein upon the addition or removal of a peer device (P9) to or from the peer-to-peer network (P2P3) the network address (IP9) of the adjoining or withdrawing peer device (P9) is published in the peer-to-peer network (P2P3). Method according to one of claims 1-5, wherein upon the addition or removal of a peer device (P9) to or from the peer-to-peer network (P2P3) a multicast to update the one stored by the peer devices (P1-P8) Routing tables (R) takes place. Computer program product performing A method according to any one of claims 1-6 caused on several programmable computer devices. Peer-to-peer network (P2P2) with multiple peer facilities (P1-P5), each of which has a network address (IP1-IP5) assigned in a communication network (IN), each one Peer device (P1-P5) a routing table (R1-R5) with at least the network addresses (IP1-IP6) of the others Peer devices (IP1-IP5) in the peer-to-peer network (P2P2) stored. A peer-to-peer network (P2P2) according to claim 8, wherein the peer devices (P1-P5) are set up in such a way that a method according to any one of claims 1-7 is performed. Peer-to-peer network (P2P2) according to claim 8 or 9, where the peer-to-peer network (P2P2) as an embedded network is formed and in particular less than 256 peer devices (P1-P5). Peer-to-peer network (P2P2) according to one of the claims 8-10, wherein the peer devices (P1-P5) as Peer-client software for programmable devices are implemented. Peer-to-peer network (P2P2) according to one of the claims 8-11, where the peer-to-peer network (P2P2) with a distributed hash table and in particular with a chord algorithm or a Kademlia resource deployment algorithm peer-to-peer network (P2P2).