METHOD FOR OPERATING A DISTRIBUTED COMMUNICATIONS NETWORK

• US 20100303089A1
• Filed: 08/27/2008
• Published: 12/02/2010
• Est. Priority Date: 09/13/2007
• Status: Active Grant

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Gerdes, Christoph, Southall, Alan, Rusitschka, Sebnem, Kleegrewe, Christian, Kern, Claus
• Granted Patent: US 8,724,640 B2
• Time in Patent Office: Days
• US Class Current: 370/401
• CPC Class Codes: F04B 33/005 specially adapted for inflating tyres of non-motorised vehicles, e.g. cycles, tricycles
• CPC Class Codes: H04L 61/4541 Directories for service discovery
• CPC Class Codes: H04L 63/065 for group communications cryptographic mechanisms or cryptographic arrangements for key management involving conference or group key H04L9/0833
• CPC Class Codes: H04L 67/104 Peer-to-peer [P2P] networks
• CPC Class Codes: H04L 67/1065 Discovery involving distributed pre-established resource-based relationships among peers, e.g. based on distributed hash tables [DHT] pre-configuration of logical or physical connections H04L67/1053
• CPC Class Codes: H04L 67/51 Discovery or management thereof, e.g. service location protocol [SLP] or web services

Abstract

A method for operating a dezentralized communication network with network nodes is provided. The method is based on protocols in conventional peer-to-peer networks. The method provides rapid searching of resources whereby each network node manages a table containing information regarding all the other network nodes, such that a network that contains the resource is immediately retrieved among the table entries. Furthermore, the table contains device names of technical components on which the network nodes are mapped, so that a technical component is directly addressed also via its device name without use of the search process.

Claims

1-27. -27. (canceled)

28. A method for operating a distributed communications network with a plurality of network nodes, each network node being assigned an identity value from a range of identity values and an address to communicate with other network nodes, and each network node being responsible for a sub-range of identity values from the range, comprising:

managing a table by each operational network node, the table containing an entry for each operational network node in the communications network, the entry comprising the identity value and the address of the respective network node;

sending regularly activity messages by each operational network node to the other network nodes of the communications network, the activity messages each containing the identity value and the address of the respective network node; and

synchronizing the table by each operational network node, upon receiving an activity message, with the contents of the activity message.

29. The method as claimed in claim 28, wherein the method is used in a communications network of an engineering system with a plurality of engineering components, comprising:

assigning a device identity to the engineering components for accessing the engineering component;

assigning a network node of the communications network to at least one device identity, each entry in the table of the network node also contains the device identity to which the network node corresponding to the entry is assigned; and

transmitting additionally with the activity message the device identity that is assigned to the network node which is sending the activity message.

30. The method as claimed in claim 28, wherein the activity messages are transmitted into the communications network by the respective network node as broadcast messages.

31. The method as claimed in claim 28, further comprising:

monitoring the network nodes in order to detect when a network node becomes inactive, the monitoring being performed via a monitoring node which is assigned to the network node,

wherein the monitoring node monitors whether the network node is transmitting activity messages, and

wherein, when the network node is no longer transmitting activity messages, the monitoring node transmits a deactivation message to all the other network nodes, the deactivation message containing the identity value of the network node, and

wherein the inactive network node lo longer sends activity messages.

32. The method as claimed in claim 31, wherein the deactivation message is transmitted into the communications network by the monitoring node as a broadcast message.

33. The method as claimed in claim 31, wherein the monitoring node is a network node that is a neighbor of the monitored network node in the sequence of identity values, and wherein two neighboring network nodes are the monitoring nodes of a monitored network node.

34. The method as claimed in claim 33, wherein the monitoring node, in the event that it receives an activity message from a network node that is a new addition to the communications network or newly activated network node, checks whether the new network node is a new neighboring network node, wherein, when the new network node is a new neighboring network node, the monitoring node starts to monitor the new network node.

35. The method as claimed in claim 28, wherein a network node transmits a deactivation message containing its identity value to all the other operational network nodes when the network node becomes inactive.

36. The method as claimed in claim 28, wherein the table of a network node contains entries for all the identity values in the range, a status field being used for each entry to indicate whether the network node of the entry is present in the communications network or operational or inactive.

37. The method as claimed in claim 36, wherein, in case a network node receives activity messages from a network node that was previously not yet present in the communications network or was previously inactive, the corresponding entry in the table for the previously not yet present or previously inactive network node is synchronized with the contents of the activity message, the status field of the corresponding entry being set to active.

38. The method as claimed in claim 37, wherein a network node receiving a deactivation message sets the status field of the entry of the network node given by the identity value in the deactivation message to inactive.

39. The method as claimed in claim 36, wherein each operational network node is responsible for the sub-range of identity values between its identity value and the next larger or next smaller identity value of its operational neighbor node.

40. The method as claimed in claim 39, wherein, when the status field of an entry in the table for the operational network nodes changes, the sub-ranges of the identity values for which the operational network nodes are responsible are adapted based upon the changing number of operational network nodes.

41. The method as claimed in claim 28, wherein resources are published in the communications network by some of the network nodes by a keyword assigned to a resource being mapped onto an identity value, the resource or a link to the resource being saved on a publication node, which is the network node that is responsible for the sub-range containing the identity value on which the keyword is mapped.

42. The method as claimed in claim 41, wherein the identity values are hash values, the keyword being mapped onto the identity value by a hash function, and wherein the hash function is selected to achieve an even distribution of resources on the network nodes.

43. The method as claimed in any of claims 41, wherein on publishing a resource, a replication is made so that the resource or a link to the resource is saved on other network nodes in addition to the publication node.

44. The method as claimed in claim 43, wherein the additional network nodes are determined by adding prime numbers to the identity value of the publication node.

45. The method as claimed in claim 41, wherein, when the responsibility of a network node for a resource in the communications network changes, the resource is republished in the communications network.

46. The method as claimed in claim 41, wherein searching for resources in the communications network is done by a searching network node mapping the keyword of the resource onto the identity value and using its table to identify the network node responsible for the resource, this network node being addressed via its address in the table.

47. A distributed communications network, comprising:

a plurality of network nodes, each network node being assigned an identity value from a range of identity values and an address to communicate with other network nodes, and each network node being responsible for a sub-range of identity values from the range,

wherein the communications network is configured such that

each operational network node manages a table containing an entry for each operational network node in the communications network, the entry comprising the identity value and the address of the network node,

each operational network node regularly sends activity messages to the other network nodes of the communications network, the activity messages each containing the identity value and the address of the network node, and

each operational network node, upon receiving an activity message, synchronizes its table with the contents of the activity message.