Filtering updated alias information

Abstract

To provide methods, systems, and apparatus for implementing a request for filtered updated resources associated with aliases.SOLUTION: A CPC may be configured to request a filtered updated list of registered aliases associated with one or more resources. The updated list may be filtered based on a state of a DCN, on which the CPC is hosted. For example, the updated list may be filtered based on a timestamp associated with receipt of a previous list, based on a group the DCN is associated with, based on manufacturers, and / or based on a security level (associated with the DCN and / or associated with updates).SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to filtering updated alias information. [Background technology]

[0002] A process automation facility can contain numerous sensors, actuators, and distributed control nodes (DCNs) that work together to perform a variety of different tasks, including managing process control loops. Keeping track of these various components can be cumbersome. To help humans better manage many components intuitively, an alias server, such as a global discovery server (GDS), can be used to assign human-friendly aliases to individual components. Summary of the Invention [Problem to be solved by the invention]

[0003] Described herein are embodiments for reducing network traffic and / or volume between process automation nodes, such as a DCN-hosted cross-platform client (CPC) and a GDS. More particularly, but not by way of limitation, described herein are techniques for filtering alias information to reduce the size of data exchanged between process automation nodes. In some embodiments, this filtering may be time-based. For example, the GDS may record the time an alias was registered. A client requesting an alias update from the GDS may specify, for example, the time it last received an alias update, and the GDS may return only aliases that have been modified (e.g., added, deleted) since the specified time. As a result, data returned by the GDS does not include alias information already owned by the client, reducing the amount of data transferred. Given the large number of nodes typical of a process automation facility and the frequency of alias changes, this reduction in the size of the transmitted data can significantly reduce the burden on the process automation network. [Means for solving the problem]

[0004] In various embodiments, a CPC hosted on a DCN at a process automation facility is configured to receive a list of registered aliases from an alias server via one or more process automation networks. In various embodiments, the list of registered aliases includes resources hosted by other DCNs on the process automation network and human-readable aliases assigned to the resources. In various embodiments, the CPC is configured to record in memory one or more aspects of the state of the DCN at the time the DCN received the list of registered aliases. In various embodiments, the CPC is configured to formulate a request for an updated list of registered aliases. In various embodiments, the request includes an indication of one or more aspects of the state of the DCN that cause the alias server to return fewer than all registered aliases. In various embodiments, the CPC is configured to send the request for the updated list of registered aliases to the alias server via one or more of the networks. In various embodiments, the CPC is configured to receive an updated list of registered aliases from the alias server via one or more of the networks, wherein the updated list of registered aliases excludes one or more resources having corresponding aliases that satisfy one or more criteria associated with the state of the DCN.

[0005] In various embodiments, one or more aspects of the state of the DCN include a time when the DCN received the list of registered aliases, and one or more criteria include resources having corresponding aliases that have not changed since the time. In various embodiments, the updated list of registered aliases includes registered aliases that have been modified since the time associated with receiving the list of registered aliases. In various embodiments, the updated list of registered aliases includes registered aliases that have been added since the time associated with receiving the list of registered aliases. In various embodiments, the updated list of registered aliases includes registered aliases that have been deleted since the time associated with receiving the list of registered aliases. In various embodiments, after receiving the list of registered aliases, one or more selected registered aliases are assigned to resources hosted by another DCN on the process automation network. In various embodiments, one or more selected registered aliases are included in the updated list. In various embodiments, after receiving the list of registered aliases, one or more of the registered aliases are deallocated from one or more resources hosted by other DCNs, and in various embodiments, the one or more deallocated registered aliases are included in the updated list.

[0006] In various embodiments, the features disclosed herein may be implemented using one or more processors. In various embodiments, the features disclosed herein may be implemented using a system including one or more storage devices that store instructions and one or more processors operable to execute instructions that cause the one or more processors to perform operations associated with the disclosure herein. In some embodiments, the features disclosed herein may be implemented using a non-transitory computer-readable medium that stores software including instructions executable by one or more computers, the instructions, when executed, causing the one or more computers to perform operations associated with the disclosure herein.

[0007] It should be appreciated that all combinations of the foregoing concepts and additional concepts described in more detail herein are contemplated as part of the subject matter disclosed herein, for example, all combinations of claimed subject matter appearing at the end of this disclosure are contemplated as part of the subject matter disclosed herein. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 illustrates a schematic diagram of an exemplary environment in which selected aspects of the present disclosure may be implemented. [Figure 2] FIG. 1 illustrates a schematic diagram of an exemplary environment in which an alias list is received from a GDS by a CPC hosted on a DCN. [Figure 3] FIG. 1 illustrates a schematic diagram of an exemplary environment in which a request for filtered information is sent from a CPC to a GDS. [Figure 4] FIG. 1 illustrates a schematic diagram of an exemplary environment in which an updated alias list is received from a GDS by a CPC hosted on a DCN. [Figure 5] FIG. 1 illustrates generally an exemplary method for carrying out aspects of the present disclosure. [Figure 6]FIG. 1 illustrates a schematic diagram of an exemplary computer architecture in which selected aspects of the present disclosure may be implemented. DETAILED DESCRIPTION OF THE INVENTION

[0009] Described herein are embodiments for reducing network traffic and / or volume between process automation nodes, such as a CPC (hosted by a DCN) and a GDS. More particularly, but not exclusively, described are techniques that enable filtered searches of alias information to reduce the size of data exchanged between process automation nodes. In some embodiments, this filtering may be based on time.

[0010] A DCN may include one or more input / output (I / O) channels associated with various types of equipment in a process automation facility. Output channels may be associated with output devices such as actuators, valves, dampers, etc. Input channels may be associated with input devices such as various types of sensors, flow meters, compute nodes, etc. The DCN may drive output channels that control output devices based on data received from one or more data sources, such as one or more remote DCNs (or components thereof) to which the DCN subscribes.

[0011] Process automation equipment, such as a DCN, may be configured to communicate with other process automation equipment using a variety of open (e.g., non-proprietary) and / or standardized communication protocols, referred to herein as "cross-platform." Cross-platform communication protocols may be governed by various regulations and / or standards, such as, for example, the Open Platform Communication (OPC) Unified Architecture (UA). Accordingly, in various examples described herein, the DCN is described as hosting one or more "OPC UA clients" and / or one or more "OPC UA servers," although this is not intended to be limiting. The DCN may host other types of cross-platform clients and / or servers; OPC UA is merely one example.

[0012] The DCN may host various cross-platform clients (CPCs) and / or cross-platform servers (CPSs), which may use the DCN's capabilities (e.g., I / O channels) to monitor and / or control various process automation devices. The CPCs / CPSs may monitor and / or control devices using IP addresses, serial numbers, etc., and may also monitor and / or control devices using aliases, e.g., human-friendly names that allow humans to more intuitively identify and manage devices. Thus, aliases are associated with various components of a process automation facility and may include easily interpretable strings, such as "Valve1" and "Sensor2 I / O Channel." These aliases may be generated with or without user input. For example, these aliases may be generated automatically by components within the process automation network and / or based on user input received by components communicating with the process automation network.

[0013] In some cases, aliases may change. For example, aliases may be modified, reassigned, orphaned, and / or deleted. These changes may be in response to various events, such as the addition, removal, and / or replacement of components. As a result, there is frequent communication and / or synchronization between the GDS and the CPC to address these changes. The CPC may use the "FindAlias" method to obtain a list of nodes and corresponding registered aliases from the GDS, but much of the returned information may be redundant as it has not changed since the most recent "FindAlias" exchange.

[0014] The techniques described herein enable filtered searches of alias information to reduce the size of data exchanged between process automation nodes. Filters may be based on temporal considerations (e.g., time frame), component / equipment attributes (e.g., individual or by group), security, manufacturer, location, etc. The GDS may record resources (e.g., sensors or actuators managed by the CPS) and the aliases assigned to those resources. The GDS may also record other information, such as timestamps, group information, etc., associated with receiving and / or recording resources and aliases.

[0015] As an example, a CPC requesting an alias update from a GDS can specify a time, such as the timestamp generated when the CPC last received an alias update. For example, FindAlias(“[^^]addedSince 2023-01-02T14:40:00”) or FindAlias(“[^^]deletedSince 2023-01-02T14:40:00”), and the GDS can return only aliases that have been modified (e.g., added, deleted) since the specified time. As a result, the data returned by the GDS will no longer include alias information that the CPC already possesses. Therefore, the amount of data transferred is reduced. Considering the large number of components that are typical in a process automation facility, as well as the frequency of alias changes, this reduction in the size of the transmitted data can significantly reduce the burden on the process automation network.

[0016] In various embodiments, the CPC may record alias updates (e.g., resources and associated aliases) as well as the state of the DCN in which the CPC is hosted (e.g., temporal state, active state, grouping state, etc.) The CPC may use this recorded information to request alias updates, for example, with respect to the previous alias list and / or the state of the DCN at the time the previous alias list was received.

[0017] In some embodiments, the CPC may be configured to receive a list of registered aliases from the GDS, the list including resources hosted by a DCN on the process automation network and aliases assigned to the resources. The received list of registered aliases and the state of the DCN on which the CPC is hosted may be recorded. A request for an updated list of registered aliases may then be formulated, the request indicating aspects of the state of the DCN. Depending on the indicated aspects of the state of the DCN included in the request, the GDS may return fewer than all registered aliases. This may avoid returning registered aliases that have not changed for a previous request, thus reducing transmission over the process automation network. The CPC may send the formulated request to the GDS. In response, the CPC may receive an updated list of registered aliases from the GDS (excluding one or more resources having corresponding aliases that meet one or more criteria associated with the state of the DCN).

[0018] Criteria associated with the state of the DCN, which when met, may cause a resource with the corresponding alias to be removed from the updated list, may include temporal criteria corresponding to one or more components (e.g., a timestamp associated with a previous request or receipt of information), active state criteria corresponding to the activity of one or more components, performance criteria corresponding to performance indicators of one or more components, security criteria corresponding to the security level of one or more components, grouping criteria corresponding to the organization and / or hierarchy of one or more components, etc. Taking temporal criteria as an example, an aspect of the state of the DCN (indicated in the request for an updated list) may include a timestamp generated when the DCN received the previous list of registered aliases. The criterion may be met when the resource with the corresponding alias has not been modified since that time.

[0019] The updated list of aliases may include registered aliases that have been modified, added, and / or deleted since the time associated with receiving the previous list of registered aliases. For example, after receiving the list of registered aliases, one or more selected registered aliases may be assigned to resources hosted by another DCN on the process automation network and included in the updated list. As another example, after receiving the list of registered aliases, one or more of the registered aliases may be deallocated from one or more resources hosted by other DCNs and included in the updated list.

[0020] 1 schematically illustrates an exemplary environment in which selected aspects of the present disclosure may be implemented, according to various embodiments. A GDS 2 includes a server alias list 4 that includes resources 6A and corresponding aliases 8A. As described herein, these resources include components within a process automation network, and these aliases may include human-friendly characterizations of these resources; for example, a resource may be characterized as "Sensor7" instead of being characterized by, for example, the hex code "7B316" by default, or by a cryptographic identifier (e.g., "opc.tcp: / / 10.0.1.1:4840;ns=5;i=5242").

[0021] The GDS 2 may communicate with the DCN 12 over the process automation network 10. The DCN 12 may include a memory 22. The memory 22 may store instructions for executing the CPC 14. The memory 22 may also store one or more states associated with the CPC 14. These states may reflect, for example, power, performance, security, timestamps, grouping, etc. associated with operation and / or communication of information.

[0022] 2 shows that GDS2 transmits server alias list 4 to DCN 12. In particular, GDS2 may transmit server alias list 4, including resources 6A and aliases 8A, to CPC 14. Thus, client alias list 16 may include information identical to the information received from GDS2, e.g., resources 6A and aliases 8A, or may include alternative information. In some embodiments, client alias list 16 may include information generated and / or derived based on, but not identical to, the information transmitted from GDS2. For example, client alias list 16 may include information associated with state 24 (contained in memory 22) and / or may modify the received information based on the information associated with state 24.

[0023] Thus, client alias list 16 may reflect resources 6A and / or aliases 8A received from GDS2 and / or may reflect resources 6A and / or aliases 8A associated with timestamp information, group information, performance information, manufacturer information, security information, etc. For example, client alias list 16 may include resources 6A and / or aliases 8A and information indicating the time they were received from GDS2, the time span since the last known update, the expected expiration date, etc. Similarly, client alias list 16 may include resources 6A and / or aliases 8A and information indicating associated security protocols, such as the authorization of CPC 14 indicating whether GDS2 is configured to provide update information upon request. As another example, client alias list 16 may include resources 6A and / or aliases 8A and information indicating the organization and / or hierarchy associated with resources 6A, aliases 8A, and / or CPC 14.

[0024] FIG. 3 illustrates the CPC 14 sending a filtered update request 26 to the GDS 2 via the process automation network 10. As previously described, associations between resources and aliases may change frequently. For example, resources and / or aliases may be added, deleted, modified, or replaced. Therefore, updates are necessary to ensure that CPCs included in the process automation network can effectively communicate information. Compared to FIG. 2, the resources and aliases on the server alias list 4 have been updated. Thus, the server alias list 4 now includes updated resources 6B and updated aliases 8B. The updated resources 6B and updated aliases 8B may include both updated resources and aliases and previously known resources and aliases, or may include only updated (e.g., latest reflection) resources and aliases. Due to one or more factors, such as communication protocols, security permissions, and network hardware, the CPC 14 may be configured to receive only updates corresponding to the updated resources 6B and updated aliases 8B via the update request to the GDS 2.

[0025] In a request for an unfiltered update, GDS2 may send all available information in server alias list 4, whereas in a request for a filtered update, GDS2 may send a subset of all available information in server alias list 4. For example, filtered update request 26 may request that updates be filtered based on time considerations. In other words, filtered update request 26 may request only updated resources 6B and updated aliases 8B that were updated since a specified time. The specified time may correspond to the last known receipt of information from GDS2 by CPC 14. Thus, filtered update request 26 may conserve network resources by reducing the data communicated between GDS2 and CPC 14 based on CPC 14's filtered update request 26 requesting only a customized subset of the available data on GDS2's server alias list 4.

[0026] In some embodiments, filtered update request 26 may be formulated based on aspects of state 24 in memory 22. State 24 may reflect one or more states of information associated with DCN 12 (including CPC 14). For example, state 24 may reflect temporal considerations, such as the time when information was communicated via DCN 12 and / or the time when DCN 12 was inactive or active. State 24 may also reflect group considerations, such as whether DCN 12 is assigned to a group, the manufacturer of DCN 12, the process loops in which DCN 12 is involved, the security level of DCN 12, the process control loops in which DCN 12 is involved, etc. Thus, filtered update request 26 may be formulated based on one or more aspects of state 24. As an example, filtering may be based on resources involved in process loops of DCN 12, such that resources and aliases not involved in process loops of DCN 12 (and therefore, which may not be associated with CPC 14) are filtered out.

[0027] Figure 4 shows GDS2 sending updated resources 6B and updated aliases 8B to DCN 12. As described with respect to Figure 3, CPC 14 can send a filtered update request 26 to GDS2, where the request is filtered based on various considerations such as time frame, grouping, etc. In Figure 4, client alias list 16 is shown as having received updated resources 6B and updated aliases 8B from GDS2 over process automation network 10. As previously described, the resources and aliases included in client alias list 16 may be based on, and in some embodiments may differ from, the resources and aliases included in server alias list 4. For example, if the filtered update request 26 (see FIG. 3 ) filters updates based on grouping (e.g., by manufacturer, membership in a process control loop, section or role within a facility, etc.) and time, then no update will be sent from the GDS2 to the CPC 14 if the update does not relate to the grouping (e.g., with respect to manufacturer, membership in a process control loop, etc.), even though updates may have occurred temporarily since the previous receipt of information by the CPC 14 from the GDS2.

[0028] Thus, using filtered update requests can conserve resources because the GDS2 does not need to process the compilation of resources and aliases that have been filtered out by the filtered update request 26. Furthermore, the filtered out resources and aliases may not need to be communicated over the process automation network 10, reducing the load on available bandwidth, for example. Additionally, the CPC 14 may not need to locally filter the information included in the update transmission from the GDS2 because the included information should include only the desired updated resources and aliases. Thus, many advantages associated with resource conservation are associated with the embodiments disclosed herein.

[0029] 5 includes a flowchart illustrating an exemplary method 500 for carrying out aspects of the present disclosure. For convenience, the operations of the flowchart are described with reference to a system that performs the operations. This system may include various components of various computer systems. Furthermore, while the operations of method 500 are shown in a particular order, this is not intended to be limiting. One or more operations may be reordered, omitted, and / or added. The methods, systems, and apparatuses disclosed herein, including but not limited to method 500, may be implemented using one or more processors.

[0030] In block 502, the system receives a list of registered aliases from a GDS via one or more process automation networks. The list of registered aliases may include resources hosted by other DCNs on the process automation network and human-readable aliases assigned to the resources.

[0031] In block 504, the system records one or more aspects of the state of the DCN when it received the list of registered aliases. The recording can be in memory local to the DCN or in a remote memory. In some embodiments, the state of the DCN can include a temporal state, a manufacturing state, a security state, etc. For example, the state of the DCN can include a temporal state, and the recorded aspect can be a timestamp reflecting the temporal state when the list of registered aliases was received (block 502 above).

[0032] At block 506, the system formulates a request for an updated list of registered aliases. The request may include an indication of one or more aspects of the state of the DCN that cause the GDS to return fewer than all registered aliases. For example, the request may include a temporal indication (e.g., based on a timestamp associated with previously received information) indicating that only updates from a particular time onward are requested. As previously described, other indications may additionally or alternatively be included. These indications may result in a subset of the entire available list of registered aliases being sent. In some embodiments, these indications may result in a request for no updates (based on a general lack of updates or the updates not meeting criteria associated with the indications included in the request).

[0033] In block 508, the system sends a request for an updated list of registered aliases to the GDS over one or more of the networks.

[0034] In block 510, the system receives an updated list of registered aliases from the GDS via one or more of the networks. The updated list of registered aliases excludes one or more resources having corresponding aliases that satisfy one or more criteria associated with the state of the DCN. As described above, the instruction associated with the state of the DCN may include, for example, a temporal instruction. Of the entire list of registered aliases, one or more resources having corresponding aliases may be excluded from the updated list of registered aliases received by the CPC from the GDS based on, for example, satisfying the temporal criterion. In other words, if one or more resources having corresponding aliases have not changed compared to the CPC's previous receipt of the list of registered aliases, they may satisfy the temporal criterion of not being changed for a certain period of time and therefore be excluded from the updated list. This avoids unnecessary processing and transmission of data by the process automation network and / or components included therein.

[0035] In some embodiments, the updated list of registered aliases includes registered aliases that have been added, deleted, and / or modified since the time associated with receiving the list of registered aliases. As described in block 502, the system may receive an initial list of registered aliases. In some embodiments, after receiving the list of registered aliases, one or more selected registered aliases may be assigned to or deallocated from resources hosted by another DCN on the process automation network. As described in block 510, the system may receive an updated list of registered aliases, and in some embodiments, after receiving the list of registered aliases, one or more selected registered aliases are included in the updated list if they are assigned to resources hosted by another DCN. Alternatively, in some embodiments, after receiving the list of registered aliases, one or more selected registered aliases are included in the updated list if they are deallocated from resources hosted by another DCN.

[0036] 6 is a block diagram of an exemplary computing device 610 that may optionally be utilized to perform one or more aspects of the techniques described herein. The computing device 610 typically includes at least one processor 614 that communicates with several peripheral devices via a bus subsystem 612. These peripheral devices may include, for example, a storage subsystem 624 including a memory subsystem 625 and a file storage subsystem 626, a user interface output device 620, a user interface input device 622, and a network interface subsystem 616. The input and output devices allow a user to interact with the computing device 610. The network interface subsystem 616 provides an interface to external networks and is coupled to corresponding interface devices in other computing devices.

[0037] The user interface input devices 622 may include a keyboard, a pointing device such as a mouse, a trackball, a touchpad, or a graphics tablet, a scanner, a touchscreen integrated into a display, a voice recognition system, an audio input device such as a microphone, and / or other types of input devices. In general, use of the term "input device" is intended to include all possible types of devices and methods for inputting information into the computing device 610 or a communications network.

[0038] The user interface output devices 620 may include a display subsystem, a printer, a fax machine, or a non-visual display such as an audio output device. The display subsystem may include a cathode ray tube (CRT), a flat panel device such as a liquid crystal display (LCD), a projection device, or some other mechanism for creating a visible image. The display subsystem may also provide a non-visual display, such as via an audio output device. In general, use of the term "output device" is intended to include all possible types of devices and methods for outputting information from the computing device 610 to a user or to another machine or computing device.

[0039] Storage subsystem 624 stores programming and data structures that provide the functionality of some or all of the modules described herein. For example, storage subsystem 624 may include logic to perform selected aspects of the method illustrated in Figure 5, as well as logic to implement various aspects illustrated in Figures 1-4.

[0040] These software modules are typically executed by the processor 614 alone or in combination with other processors. The memory 625 used in the storage subsystem 624 may include several memories, including a main random access memory (RAM) 630 for storing instructions and data during program execution and a read-only memory (ROM) 632 in which fixed instructions are stored. The file storage subsystem 626 may provide persistent storage of program and data files and may include a hard disk drive, a floppy disk drive with associated removable media, a CD-ROM drive, an optical drive, or a removable media cartridge. Modules that implement the functionality of some embodiments may be stored by the file storage subsystem 626 in the storage subsystem 624 or on other machines accessible by the processor 614.

[0041] The bus subsystem 612 provides a mechanism for the various components and subsystems of the computing device 610 to communicate with each other as intended. Although the bus subsystem 612 is shown schematically as a single bus, alternative embodiments of the bus subsystem may use multiple buses.

[0042] The computing device 610 can be of various types, including a workstation, a server, a computing cluster, a blade server, a server farm, or any other data processing system or computing device. Due to the ever-changing nature of computers and networks, the description of the computing device 610 shown in FIG. 6 is intended only as a specific example to illustrate some embodiments. Many other configurations of the computing device 610 can have more or fewer components than the computing device shown in FIG. 6. The techniques disclosed herein may be implemented by a system including one or more processors, a storage device with instructions executable by the one or more processors, and / or a non-transitory computer-readable medium having stored thereon instructions executable by one or more computers.

[0043] While several embodiments have been described and illustrated herein, various other means and / or structures for performing the functions and / or obtaining the results and / or one or more advantages described herein may be utilized, and each such variation and / or modification is considered to be within the scope of the embodiments described herein. More generally, all parameters, dimensions, materials, and configurations described herein are exemplary, and the actual parameters, dimensions, materials, and / or configurations will depend on the particular application for which the teachings are used. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments described herein. Accordingly, it should be understood that the above-described embodiments are presented by way of example only, and that, within the scope of the appended claims and their equivalents, the embodiments may be practiced otherwise than as specifically described and claimed. Embodiments of the present disclosure are directed to each individual feature, system, article, material, kit, and / or method described herein. In addition, any combination of two or more such features, systems, articles, materials, kits, and / or methods, where not mutually inconsistent, is also within the scope of the present disclosure. [Explanation of symbols]

[0044] 2 Global Discovery Server (GDS) 4 Server Alias ​​List 6A Resources 6B Updated Resources 8A Alias 8B Updated Aliases 10 Process Automation Networks 12 Distributed Control Node (DCN) 14 Cross-Platform Client (CPC) 16 Client Alias ​​List 22 Memory 24 Status 26 Requesting Filtered Updates 500 ways 610 Computing Devices 612 Bus Subsystem 614 processor 616 Network Interface Subsystem 620 User Interface Output Device 622 User Interface Input Devices 624 Storage Subsystem 625 Memory Subsystem 626 File Storage Subsystem 630 Main Random Access Memory (RAM) 632 Read-Only Memory (ROM)

Claims

1. 1. A method implemented by a cross-platform client hosted on a distributed control node (DCN) in a process automation facility, the method being implemented using one or more processors; receiving a list of registered aliases from an alias server over one or more process automation networks, said list of registered aliases comprising: resources hosted by other DCNs on the process automation network; a human-readable alias assigned to said resource; and recording in memory one or more aspects of the state of the DCN when it received the list of registered aliases; formulating a request for an updated list of registered aliases, said request including an indication of one or more of said one or more aspects of said state of said DCN that cause said alias server to return fewer than all registered aliases; sending the request for an updated list of registered aliases to the alias server via one or more of the process automation networks; receiving the updated list of registered aliases from the alias server via one or more of the process automation networks, wherein the updated list of registered aliases excludes one or more resources having corresponding aliases that satisfy one or more criteria associated with the state of the DCN; A method comprising:

2. 2. The method of claim 1, wherein the one or more aspects of the state of the DCN include a time at which the DCN received the list of registered aliases, and the one or more criteria include resources with corresponding aliases that have not been changed since that time.

3. 3. The method of claim 2, wherein the updated list of registered aliases includes registered aliases that have been modified since the time associated with receiving the list of registered aliases.

4. 3. The method of claim 2, wherein the updated list of registered aliases includes registered aliases that were added since the time associated with receiving the list of registered aliases.

5. 3. The method of claim 2, wherein the updated list of registered aliases includes registered aliases that have been deleted since the time associated with receiving the list of registered aliases.

6. The method of claim 1 , wherein after receiving the list of registered aliases, one or more selected registered aliases are assigned to resources hosted by another DCN on the process automation network.

7. The method of claim 6 , wherein the one or more selected registered aliases are included in the updated list.

8. 2. The method of claim 1, wherein after receiving the list of registered aliases, one or more of the registered aliases are deallocated from one or more of the resources hosted by the other DCN.

9. The method of claim 8 , wherein the one or more unassigned registered aliases are included in the updated list.

10. one or more storage devices for storing instructions; one or more processors, executing the instructions to cause the one or more processors to: receiving a list of registered aliases from an alias server via one or more process automation networks including a cross-platform client hosted on a distributed control node (DCN), wherein the list of registered aliases comprises: resources hosted by other DCNs on the process automation network; a human-readable alias assigned to said resource; receiving, recording in memory one or more aspects of the state of the DCN when it received the list of registered aliases; formulating a request for an updated list of registered aliases, the request including an indication of one or more of the one or more aspects of the state of the DCN that cause the alias server to return fewer than all registered aliases; sending the request for an updated list of registered aliases to the alias server via one or more of the process automation networks; receiving the updated list of registered aliases from the alias server via one or more of the process automation networks, the updated list of registered aliases excluding one or more resources having corresponding aliases that satisfy one or more criteria associated with the state of the DCN; one or more processors operable to cause the processor to perform operations including A system comprising:

11. 11. The system of claim 10, wherein the one or more aspects of the state of the DCN include a time at which the DCN received the list of registered aliases, and the one or more criteria include resources with corresponding aliases that have not been changed since the time.

12. 12. The system of claim 11, wherein the updated list of registered aliases includes registered aliases that have been modified since the time associated with receiving the list of registered aliases.

13. 12. The system of claim 11, wherein the updated list of registered aliases includes registered aliases that were added since the time associated with receiving the list of registered aliases.

14. 12. The system of claim 11, wherein the updated list of registered aliases includes registered aliases that have been deleted since the time associated with receiving the list of registered aliases.

15. The system of claim 10, wherein after receiving the list of registered aliases, one or more selected registered aliases are assigned to resources hosted by another DCN on the process automation network.

16. The system of claim 15 , wherein the one or more selected registered aliases are included in the updated list.

17. 11. The system of claim 10, wherein after receiving the list of registered aliases, one or more of the registered aliases are deallocated from one or more of the resources hosted by the other DCN.

18. 20. The system of claim 17, wherein the one or more unassigned registered aliases are included in the updated list.

19. A non-transitory computer-readable medium storing software including instructions executable by one or more computers, said instructions, when so executed, causing said one or more computers to: receiving a list of registered aliases from an alias server via one or more process automation networks including a cross-platform client hosted on a distributed control node (DCN), wherein the list of registered aliases comprises: resources hosted by other DCNs on the process automation network; a human-readable alias assigned to said resource; receiving, recording in memory one or more aspects of the state of the DCN when it received the list of registered aliases; formulating a request for an updated list of registered aliases, the request including an indication of one or more of the one or more aspects of the state of the DCN that cause the alias server to return fewer than all registered aliases; sending the request for an updated list of registered aliases to the alias server via one or more of the process automation networks; receiving the updated list of registered aliases from the alias server via one or more of the process automation networks, the updated list of registered aliases excluding one or more resources having corresponding aliases that satisfy one or more criteria associated with the state of the DCN; A non-transitory computer-readable medium for causing operations to be performed, including:

20. 20. The non-transitory computer-readable medium of claim 19, wherein the one or more aspects of the state of the DCN include a time at which the DCN received the list of registered aliases, and the one or more criteria include resources with corresponding aliases that have not been modified since the time.

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