Addressing of redundant elements in a communication network

0001The invention relates to a system and a method for addressing at least two mutually redundant subscribers in a communication network, wherein the subscribers a unique in the communication network physical Address is assigned permanently.

0002From US 6,392,990 B1 discloses a method for the treatment of Defects known at interface components of a network. The process is to run on a computer in a Network provided with a plurality of computers, wherein the computer mutually redundant with redundant lines have connected interface units. The The method provides a transparent after restoration Network failures safe by an address list of hosts provides the network. The computer periodically checks the Communication connections to one or more of the other Computer until it at least one computer a response in Form obtained from its network address. The computer uses then the network address of the other computer to the to monitor communications link to this computer until where appropriate, the other computer is not responding. For In the event that it receives no response, the computer, the Network address of the other computer of the redundant interface unit to.

0003The invention has for its object, the availability of communication links within a communication network to increase.

0004This object is achieved by a system having the mentioned in claim 1 Features dissolved. The system is used to address at least two mutually redundant subscribers in a Communication network, wherein the subscribers each have a first unique in the communication network physical Address is assigned permanently and a group of mutually redundant subscribers each having a second in the communication network assigned unique physical address , said a group associated with second address redundant members of the group in each case as in the communication network valid address activated and deactivated is, at least one higher-level unit in each case wherein at a time to activate the second address exactly one of the redundant group of participants and to deactivate the second address for the remaining redundant subscribers the group is provided.

0005The object is achieved by a method with the in claim 5 features mentioned achieved. In the method for addressing at least two mutually redundant subscribers in a communication network participants will each a first unique in the communication network physical assigned address permanently and is a group of mutually redundant subscribers each having a second in the communication network assigned unique physical address, said a group associated second address in the redundant Members of the group in each case as in the communication network be activated and deactivated valid address may, at least one higher-level unit, the second Address in exactly one of the redundant group member activated and the second address for the remaining redundant Members of the group each disabled.

0006To increase the communication availability communication buses often highly available designed. This is z. B. by establishing a communication ring or doubling reaches the communication lines. To not only the Failure of the communication link but also the failure to control a communication unit, is in many Cases, the communication unit implemented redundantly, as these when highly available communication to the next Vulnerability is. Functional units, eg. As redundant control units or peripheral devices with redundant communication unit, which to a communication bus (line or Ring) or connected to a redundant communication bus are must be addressable. Here are two conflicting requirements: For all functions for which redundancy should be hidden, the functional unit should receive only one address. Such functions include, for, example, connecting single-channel tailed process peripherals. These Address should be switchable. For all functions which should be disclosed, the redundancy, the functional unit should or its communications unit as many addresses obtained as redundant components in the redundant unit available. Thus, a user-friendly diagnostics possible because z. B. an error, the respective address of affected component can be clearly identified. The there same requirement for maintenance and information functions. Again, not interested in the community the redundant components but exactly the state data of each component. The redundant communication unit can generally n-channel (n> 1) be constructed. The present invention satisfies the two described, seemingly contradictory requirements. As a participant in be communication network or as a node Here communication units and, where applicable Subunits designated.

0007According to an advantageous embodiment of the invention is the parent unit for detecting a failure of communication links to the subscribers and for detecting a Failure of the participants provided. The functionality of the Communication is therefore the higher-level communication unit (Or partner unit) monitors.

0008If the parent unit to the preferred channel fails reveals, it can, the currently selected as a reserve Unit of the redundant communication unit to a Switchover or takeover of the switched address cause. Advantageously, therefore, the parent unit for selecting a preferred communication link from the Communication links to a group associated with participants provided. A group mutually redundant subscriber hereinafter referred to as redundancy group. Each of the redundant sub-units has two addresses on. A first address is determined each of the subunit assigned. The other address is the second part, the so-called switchable address. The switchable address is enabled the preferred channel and at all to this redundancy group belonging redundant channels disabled. at The preferred channel fails is on the standby channel switchable Address actively connected. About the switchable Address is the common functionality of the group reached.

0009According to a further advantageous embodiment of the invention is the system for addressing at least two mutually redundant subscribers in a communication network Part of an industrial automation system. For all functions in which the allocation to the redundant Channels or redundant communication units no relevance has the component as a single-channel behaves Component. These functions include, for. Example, process data Read / write and process alarms. behaves for these functions the redundant power component on both the communication ring as well as the redundant communications as a single component. This has the advantage that the redundancy hidden remains. In automation technology, the objective is that a partner component that only process data or process alarms processed by the redundant peripheral unit, not have to worry about redundancy. If the preferred channel subunit fails, repeat the associated communication system, z. B. Ethernet, automatically the communication request and since the switchable address on the other Page responds, communication is now running on the former Standby channel without the single-channel communication unit itself must be active. Only those functional units, which address the individual sub-units must (z. B. for diagnostics and maintenance), the knowledge must have the redundancy by the addresses of the sub-units know. This has the advantage that for repair and Maintenance all the necessary information (such as data ortrichtige read and write the sub-units) with the same means can be as single-channel components. This has therefore, in their view also has the advantage that the redundancy remains hidden.

0010To a simple automatic addressing - particularly when booting the system - to achieve, according to an activated further advantageous embodiment of the invention, a the redundant subscriber group an assigned him third unique in the communication network physical address as in the communication network of the respective valid Group assigned second address and clear the remaining redundant members of the group the second address.

0011The invention is based on the shown in the figures described embodiments and will explain.

0012Show it:<dl tsize="5"><dt>1 shows</dt><dd>a system for addressing two mutually redundant Subscribers in a communication network,</dd><dt>FIG 2</dt><dd>a system with mutually redundant subscribers in a communication network with a redundant executed communication, </dd><dt>FIG 3</dt><dd>a communication unit with two redundant Subunits and</dd><dt>FIG 4</dt><dd>a system for addressing mutually redundant Subscribers in a communication network to clarify the communication relationships within the system.</dd></dl>

00131 shows a system for addressing of two mutually redundant subscribers 3, 4 in a communication network 5. Participants 3, 4 are in the embodiment of FIG 1 mutually redundant communication units a Function unit 11. The mutually redundant subscribers 3, 4 form a group 6. The redundant subscriber 3, 4 can via a communication bus 10 in the communication network 5 communicate. On the communication bus 10 is a parent Unit 7 is connected which communication unit a 12 and having a functional unit. 13 For communication Various communication links 8 to Available. The first redundant subscriber 3 is in Communication network 5 unique physical address 1 assigned permanently. The second redundant subscriber 4 is another in the communication network 5 unique physical Address 9 assigned permanently. The group 6 of each other redundant subscribers 3, 4 is another in the communication network assigned 5 unique physical address 2, which at each of the two redundant subscriber 3, 4 of the 6 group as the communication network 5 valid address be activated and deactivated. This activation and deactivation takes place in the embodiment of FIG 1 at the initiative of the parent unit 7. Here, the parent unit 7 exactly one of the two redundant Participants 3, 4 further address 2 to date, ie this address 2 at the respective subscriber 3, 4. In the other party 3, 4, however, is this address 2 disabled by the parent entity. 7 A thus carried out assignment of physical addresses 1, 2, 9 causes the mutually redundant subscriber 3, 4 both about their respective first address 1, 9 individually uniquely addressable or addressable are, as addressable as a group 6 of the physical address 2 are. The physical address 2 is thereby one of two each by the redundant subscribers 3, 4 and Bus segments formed communication channels as a preferred channel assigned. The respective other communication channel is held aside channel. The functionality of the Communication is monitored by the parent unit. 7 If the parent unit 7 the failure or Disruption of communication with the primary channel reveals causes them to instantaneously set as reserve participants 3 or 4 of the group to a switchover or takeover the so-called switched address. 2

0014In previously known system is in the mutually redundant Units either only one identical address for both units or only one address for the preferred channel and an address for the standby channel provided. at The preferred channel fails then takes over the part of communication unit the previously standby channel was, as soon as possible the preferred channel and the address of the preferred channel. From the user perspective but then changes the entire communications unit the address. In both methods previously known however, it is not possible to request reasonable to resolve that each of the redundant units unique in the network should be addressed. Diagnostic and maintenance tools known knowledge in the prior art process therefore not, which of the two mutually redundant Communication units communicate.

0015Figure 2 shows another embodiment of a system for addressing two mutually redundant subscribers in a communication network with a redundant bus system. Communication units 22, 31, 33 are redundant Communication links 20, 21, z. B. communication buses, coupled together. The communication units 22, 31, 33 fulfill communication tasks of functional units 23, 32, 34. When the communication unit 33 for the functional unit 34 is a redundant communication unit, which two redundant sub-units 35 or 36 contains. Similarly, the communication unit 22 of the superordinate functional unit 23 as a redundant parent Communication unit formed. Another participant Communication is the single-channel functional unit 32, which communicates via the single-channel communication unit 31st

0016The communication units 22, 31 and the sub-units 35, 36 is in each case a fixed physical in the communication network assigned unique address. In the embodiment, according to Figure 2 this physical address is as so said MAC address 24, 25, 26 and 27 is executed (MAC = Media Access Control). As a MAC address usually is shown great hexadecimal by 48 bits, and in the Usually unchangeable identification number of a subscriber referred to in a communication network. The MAC address is a hardware address that uniquely identifies a node in the network is used. According to the OSI reference model (OSI = Open System Interconnection), which as a 7-layer model is referred to, the second layer, so-called data link layer, into two sub-layers divided, wherein the MAC layer is the lower layer. The MAC layer serves to organize the bit transmission layer in logical groups of information, the so-called Framework, and for fault finding, for controlling the flow of data and to identify the computer in the network. It will now be an additional way for the redundant sub-units 35, 36 Address 28 introduced. That is, each of the partial units 35, 36 is replaced by the two addresses. The respective first address 26, 27 is fixed to the respective sub-unit 35 or 36 assigned, while the other address 28, the so-called switchable Adress is. The switchable address 28 is the Priority Channel activated and deactivated at the reserve channel. at The preferred channel fails or the communications link 20 or the second address 28 21 is active on the standby channel connected. Via the second address 28 is the common Functionality of the functional unit 34 accessible.

0017One possible implementation on MAC address level is as follows out: Each of the two sub-units 35, 36 includes two globally unique MAC addresses 26, 27 and 28. Those Sub-unit 35, 36 that the after the initial power System is first ready, automatically started Both their addresses 26, 27 and 28 - an address as determined assigned address 26 or 27 and the address other than the so-called switched address 28 The one sub-unit 35, 36, which starts subsequently activated only her as a dedicated Address 26 and 27. The so-called switched address 28 makes this sub-unit 35, 36 inactive. The entity 35, 36 However, prepares it before, the switched MAC address 28 of the other sub-unit 35, to take 36, if these other sub-unit 35, 36 fails.

0018The higher-level communication unit 22 in the embodiment redundantly implemented according to Figure 2, that is, it via the communication path 20 by means of the address 24 or via the communication path 21 by means of the address 25 is approachable. The higher-level communication unit 22 has the task of communicating to the redundant communication unit 33 monitor. This monitoring involves both the preferred channel (Primary) and the spare channel. at Failure of the reserve channel (either by failure of the bus connection or failure of the respective reserve sub-unit 35 or 36), this failure to a master control system reported. If the preferred channel is the parent Functional unit 23 to the respective reserve unit sent 35 or 36 a message, even preferred channel to will. This sub-unit 35, 36 retains its fixed address 26 and 27 and activated when the switched address 28 for the Preferred channel. The former primary channel both on the internal connection as well as from the parent communication unit 22 Instructs its preferred channel address 28 to Disable (if it has not already failed, thereby is communicatively no longer active).

0019The awarding of the switchable address is, for example, with one of the two methods described below: In the first proposed method manages the parent Communication unit 22, the switchable addresses and they will award at each first activation of a redundant Group. At the factory, on each of the subunits 35, 36, an address 26, 27 is set, the other address 28 is 0 or not active. Only at the start of Sub-unit 35, 36 in a redundant group is the second Address 28 used. The second proposed method , each sub-unit 35, 36 of the associated redundancy group Communication unit 33 globally unique factory two Addresses set. For example, sub-unit 35 receives the address "a + x" and the sub-unit 36 ​​the addresses "B + y". When you turn the mutually redundant sub-units 35, 36 activates the first energized subunit 35 its switchable address "x". The subsequently switched Part unit 36 ​​rejects its switchable address "y" and takes over the address "x" as a switchable address.

0020Diagnostic and maintenance tools are mostly like the single-channel Functional unit 32 with a single-channel communication unit 31 realized. The single-channel communication unit 31 is again a fixed physical address 29 assigned. The communication unit 31 communicates via a Switch 30 with the redundant communication paths 20 or 21 diagnostic and maintenance tools know both addresses 26, 27 of the redundant communication unit 33, as it is the target Diagnostics and maintenance, single replaceable component units 35, to diagnose 36th In a communication request is a separate response of each hardware unit required, using the suggested addressing mechanisms is possible.

0021Figure 3 shows an embodiment of a functional unit 40 with a redundant communication unit consisting of two Part units 41 and 42 is. The sub-units 41 and 42 communicate via communication links 43 and 44 with Other participants not shown here in a communication network. The sub-units 41, 42 are more than physical Addresses 46, 47, 48 addressable. In addition, there an internal communication link 45 between the two Part units 41 and 42. Since the address switchover described is not made through the internal communication link 45, but via the external communication links 43, 44, on the one hand, the failure of internal communication link 45 are controlled and on the other hand, in addition the failure of the external communication links 43, 44 identified and controlled.

0022Figure 4 is used to illustrate the communication relationships within a system for addressing each other redundant subscribers in a communication network. shown is a functional unit 55 with a two Part units 56, 57 existing communication unit, a single-channel communication unit 53 with a single channel Communication unit 54 and a higher-level functional unit 51 with a higher-level communication unit 52nd The higher-level communication unit 52 is on the address 60 addressable and communicates via a switch 58 with the redundant communication bus 50. The single-channel Communication unit 54 is addressed via the address 61 and communicates via the switch 59 with the redundant communication bus 50. The sub-units 56, 57 of the redundant Communication unit also communicate via the redundant Communication bus 50, and addresses are 62, 63 or 64 addressable.

0023Place the arrows marked with the reference numeral 67 the majority of the communication relationships within the displayed System. Over these communication relationships z. B. Process data and process alarms to be replaced. This communication relations work regarding the redundant Communication unit with the switched address 63 and are essentially equivalent to a communication relationship to a single-channel device. Marked with the reference numeral 66 Arrows represent the communication relationships for maintenance and diagnostics to the sub-units 56, 57 of the communication unit . In addition, there is not even here illustrated communication links with the functional unit 55. The communication relationships designated by the numeral 65 represent the functions which for communication monitoring and for the switching-on detection have an error on the priority channel required. Over these communication relationships is the communication failure detected on the spare channel and reported. in the Illustrated case, the sub-unit 57, the backup unit and therefore its switchable address 63 has not been activated.

0024In summary, the invention thus relates to a system and a method for addressing of at least two mutually redundant subscribers 3, 4 in a communication network 5, in which the users 3, 4 each have a first in the communication network 5 unique physical address 1, 9 permanently assigned. To ensure the availability of communications links within the increasing communication network, it is proposed that a group of 6 each redundant subscribers 3, 4 each have a second in the communication network assigned 5 unique physical address 2 , wherein the group 6 associated second address 2 for the redundant subscribers 3, 4 group 6 respectively as valid in the communication network 5 Address activated and can be deactivated, wherein at least one superordinate Unit 7 one at a time to activate the second address 2 is exactly one of the redundant subscriber 3, 4 of Group 6 and for deactivating the second address 2 in the remaining redundant subscribers 3, 4 of group 6 is provided.