PART III. FUNCTIONS OF WIS
- HADDOUCH Hassan
3.1 Roles in and review of WIS functions
An ongoing process for understanding user requirements, including quality of service, shall determine the functional scope and physical size of WIS, thereby ensuring the continued responsiveness of WIS to the current and future needs of the supported programmes. All supported programmes and technical commissions shall participate in this process, which shall be part of general WMO requirement reviews.
3.2 List of WIS functions
3.2.1 WIS centres collectively support the major WIS functions listed here:
(a) Collect observations, generate products, create metadata and archive information;
(b) Assign user role;
(c) Maintain and expose a catalogue of services and information;
(d) Authorize access to information by users;
(e) Deliver information to users (internal and external);
(f) Manage system performance.
Note: WIS is concerned with data management and telecommunications aspects, but the actual content of data and products falls outside the scope of WIS and is a matter for the specific programme supported.
3.2.2 The required standard interfaces to these functions are described in the WIS technical specifications (Part IV of this Manual).
3.3 Functional architecture of WIS2
The functional architecture of WIS2 is based on the concept of Global services and the WIS2 node. WIS2 architecture comprises a Global Cache (GC), a Global Broker (GB) and a Global Discovery Catalogue (GDC).
The GC provides a 24 cache of core data made available by WIS2 Nodes through the internet. It Provides reliable and low latency access to these data.
The GB provides a reliable mechanism using the open standard messaging protocols that use the publish-subscribe message pattern MQTT service for users to subscribe and get real-time notification of data available from a GC or a WIS2 Node.
The GDC Provides discovery of data and services published by WIS2 Nodes and the Global Cache
Supplementary guidance of Global services are referenced in the guide on WIS in a technical document
Note: The Guide to the WMO Information System (WMO-No. 1061), 3.3, references the functional architecture of WIS, provided as supplementary guidance for WIS centres in a technical document.
3.4 Technical architecture of WIS2 Data flow among WIS functions
The Guide to the WMO Information System (WMO-No. 1061), 3.4, provides as supplementary guidance for WIS centres a data-flow model of the WIS2 functional architecture for the required WIS2 functions, illustrating a possible implementation of major WIS2 functions
3.5 Functional requirements of a Global Cache GC
3.5.1 General
Note: The phrase “information intended for global exchange” encompasses time- and operation-critical information (data and products). Such information includes “ core data” and part of the “recommended data”, as specified in WMO Unify Data policy Resolution 1 (Cg-Ext 21)
3.5.1.1 The Global Cache Provides reliable and low latency access to data made available by WIS2 Nodes through the internet
3.5.1.2 There will be multiple Global Cache instances
3.5.2 Receive information from NCs/DCPCs
3.5.2.1 Each GC shall receive information intended for global exchange from WIS2 node (NCs and DCPCs) within its area of responsibility.
3.5.2.2 Global Cache instances and NC/DCPC use consistent topic structure in their local message brokers
3.5.2.3 Global Cache will hold "file" Data Objects
3.5.2.4 In the case of particular global and/or regional agreements, a GC could also support the exchange of agreed WIS time- and operation-critical information with other programmes
3.5.3 Exchange information with other GCs
3.5.3.1 For full global coverage, a Global Cache instance will download Data Objects and discovery metadata records from other instances
3.5.3.2 A Global Cache instance will operate independently of other Global Cache instances – albeit that one instance may download content from another
3.5.4 Anouncement of data availability
Each GC shall publish notifications of availability of data to the Global Brokers
3.5.5 Maintien a 24-hour cache
3.5.5.1 Each GC shall hold the information intended for global exchange for at least 24 hours to support subscription services, including, but not limited to, those for the GTS, and make the information available via HTTP and SFTP mechanisms
3.5.5.2 Global Cache instance shall store the discovery metadata records needed to populate the Global Catalogue
3.5.6 Data network connectivity of a GC
Each GC shall provide around-the-clock connectivity to the public and dedicated communication networks at a capacity that is sufficient to meet its global and regional responsibilities. Each GC should ensure that every telecommunication facility it employs in support of WIS has the appropriate level of availability and capacity, including, as necessary, routing and back-up arrangements. Each GC should maintain service level agreements with the suppliers of its communication links and associated hardware
3.5.6 Recovery arrangements of a GC
3.5.6.1 Each GC shall implement and operate proper procedures and arrangements to provide swift recovery or back-up of its essential services in the event of an outage.
3.5.6.2 Each GC should maintain arrangements for system back-up in case of total system failure and for partial back-up in situations otherwise affecting GC functions
3.6 Functional requirements of a global Broker GB
3.6.1 General
3.6.1.1 A Global Broker Provides a reliable MQTT service for users to subscribe and get real-time notification of data available from a GC or a WIS2 Node.
3.6.1.2 There will be multiple Global Broker instances
3.6.2 Receive information from NCs/DCPCs and GC
3.6.2.1 At least one Global Broker shall subscribe to messages from every NC/DCPC
3.6.2.2 A NC/DCPC shall push messages to at least one Global Broker instance
3.6.2.3 A Global Broker instance sahall republish messages from a subset of NC/DCPCs
3.6.2.4 Global Brokers should use distinct "channels" to keep messages from originating centers separate from messages originating from Global Cache instances
3.6.2.5 In the case of particular global and/or regional agreements, a GB could also support the exchange of agreed WIS information with other programmes
3.6.3 Exchange information with other GBs
3.6.3.1 For full global coverage, Global Broker instances sall republish messages from other Global Broker instances
3.6.3.2 A Global Broker instance will operate independently of other Global Broker instances
3.6.3.3 A Global Broker instance will be connected to at least 2 other instances
3.6.4 Announcement of data availability
3.6.4.1 GB shall provide notifications to subscribed users of new data to be downloaded from GCs
3.6.4.2 Each GC shall publish notifications of availability of data to the Global Brokers
3.6.5 Recovery arrangements of a GB
3.5.5.1 Each GB shall implement and operate proper procedures and arrangements to provide swift recovery or back-up of its essential services in the event of an outage.
3.5.5.2 Each GB should maintain arrangements for system back-up in case of total system failure (for example, an offsite Disaster Recovery Centre) and for partial back-up in situations otherwise affecting GB functions
3.7 FUNCTIONAL REQUIREMENTS OF A GLOBAL DISCOVERY CATALOGUE CDC
3.7.1 General
3.7.1.1 A Global Discovery Catalogue provides discovery of data and services published by WIS2 Nodes and the Global Cache
3.7.1.2 A single Global Discovery Catalogue instance is sufficient for WIS2
3.7.1.3 Multiple Global Discovery Catalogue instances may be deployed for resilience
3.7.2 Receive information from NCs/DCPCs and GC
3.7.2.1 A Global Discovery Catalogue instance is populated with discovery metadata records from a Global Cache instance, receiving messages about availability of discovery metadata records via a Global Broker.
3.7.2.2 Global Discovery Catalogue implements OGC-API Records API standards - both record structure and search API.
3.7.2.3 Global Discovery Catalogue advertises the availability of datasets and how/where to access them or subscribe to updates, it does not advertise the availability of specific Data Objects (i.e., data files).
3.7.3 Exchange information with other GBs
3.7.3.1 A Global Discovery Catalogue instance should connect to more than one Global Broker instance – discarding duplicate messages as needed
3.7.3.2 Global Discovery Catalogue instances operate independently of each other
3.7.4 Discovery, Access and Retrieval
Global Discovery Catalogue implements OGC-API Records API standards - both record structure and search API
3.7.5 Recovery arrangements of a GDC
3.7.5.1 Each GDC shall implement and operate proper procedures and arrangements to provide swift recovery or back-up of its essential services in the event of an outage.
3.7.5.2 Each GDC should maintain arrangements for system back-up in case of total system failure and for partial back-up in situations otherwise affecting GDC functions
3.8 FUNCTIONAL REQUIREMENTS OF A GLOBAL MONITORING GM
3.8.1 General
3.8.1.1 A Global Monitoring provides near real-time monitoring information of data made available on GTS and WIS2
3.8.1.2 WIS2. Monitoring information shall include the location and time of observations and products, the type of product, and other specific information on the data format and the content of the message.
3.8.1.3 Monitoring information will be used for the transition from GTS to WIS2 and for the implementation of GBON.
3.8.2 Sensor Center
3.9.2.1 Sensor centres shall analyse the data in real-time on GTS and WIS2. They shall Provide one record per report.
3.9.2.2 Sensor Center don’t do any aggregation or statistics
3.8.3 WIS2 Performance monitoring
3.8.3.1 The Global monitoring shall provide the performance monitoring of WIS2, including monitoring the collection and distribution of data and products intended for global exchange.
3.8.3.2 GM shall report routinely to WIS Centers, as well as to the WMO Secretariat, information concerning the status and performance of connectivity to WIS centres, including capacity and technology used. INFCOM shall review and report on the status and performance of WIS2 with the assistance of the WMO Secretariat.
3.8.3.3 GM shall collect, aggregate and visualise the statistics. The visualisation concerning observations will be harmonised and integrated into WDQMS
3.9 Functional requirements for a WIS2 node
3.9.1 General
3.9.1.1 A WIS2 node shall Provides a reliable MQTT service for Global services to subscribe and get real-time notification of data available.
3.9.1.2 Each NC/DCPC shall deploy a WIS2 node system to collect and produce data to be exchanged throuph WIS2
3.9.2 Exchange information withing WIS2 node
3.9.2.1 A WIS2 node shall push messages to at least one Global Broker instance
3.9.2.2 In the case of particular National and/or regional agreements, a WIS2 node could also support the exchange of agreed WIS information with other programmes
3.9.2.3 Each WIS2 node shall provide access to data in standards formats (BUFR, GRIB and NetCDF)
3.9.2.4 Each WIS2 node shall provide metadata in OGC-API Records API standards - both record structure and search API.
3.9.3 Announcement of data availability
3.9.4.1 WIS2 node shall provide notifications to subscribed users of new data to be downloaded
3.9.4.2 Each WIS2 node shall publish notifications of availability of data to at least 2 Global Brokers
3.9.5 Recovery arrangements of a WIS2 node
3.9.5.1 Each WIS2 node shall implement and operate proper procedures and arrangements to provide swift recovery or back-up of its essential services in the event of an outage.
3.9.5.2 Each WIS2 node should maintain arrangements for system back-up in case of total system failure and for partial back-up in situations otherwise affecting WIS2 node functions
3.9 Functional requirements of a GISC
3.95.1 General
Note: The phrase “information intended for global exchange” encompasses time- and operation-critical information (data and products). Such information includes “essential data” and part of the “additional data”, as specified in Resolution 40 (Cg-XII) – WMO policy and practice for the exchange of meteorological and related data and products including guidelines on relationships in commercial meteorological activities, Resolution 25 (Cg-XIII) – Exchange of hydrological data and products, and Resolution 60 (Cg-17) – WMO policy for the international exchange of climate data and products to support the implementation of the Global Framework for Climate Services.
Each GISC shall contribute to the Global Services: Global Cache, Global Broker, Global Discovery Catalogue, and Global Monitoring. Unlike the WIS1, GISCs are not required to run all the global services, they shall support WIS2 operations by collaboratively running a number of core shared services and decide which services they are willing to provide or contribute to.
3.5.2 Receive information from the GISC area
3.5.2.1 Each GISC shall receive information intended for global exchange from NCs and DCPCs within its area of responsibility. This requirement also intersects the WIS DAR requirement that is noted below.
3.5.2.2 See also 4.2, WIS-TechSpec-1 (Uploading of metadata for data and products) and 4.3, WIS-TechSpec-2 (Uploading of data and products).
3.5.3 Exchange information with other GISCs
3.5.3.1 Each GISC shall collect from its area information that is intended for global exchange and shall share such information with other GISCs so that all GISCs have a common holding of information available for global exchange. See also 3.5.5 (Maintain a 24-hour cache) and 3.5.8 (Coordinate telecommunications in a GISC area).
3.5.3.2 GISCs should employ the MTN and associated collaborative mechanisms to exchange the information efficiently and without detriment to the performance of any GISC.
3.5.3.3 See also 4.4, WIS-TechSpec-3 (Centralization of globally distributed data).
3.5.4 Disseminate information to the GISC area
3.5.4.1 Each GISC shall disseminate information to NCs and DCPCs within its area of responsibility, including, but not limited to, the information intended for global exchange.
3.5.4.2 See also 4.11, WIS-TechSpec-10 (Downloading files via dedicated networks), 4.12, WIS-TechSpec-11 (Downloading files via non-dedicated networks) and 4.13, WIS-TechSpec-12 (Downloading files via other methods).
3.5.5 Maintain a 24-hour cache
3.5.5.1 Each GISC shall hold the information intended for global exchange for at least 24 hours to support subscription services, including, but not limited to, those for the GTS, and make the information available via WMO request/reply (“pull”) mechanisms. Information limited to regional or AMDCN exchange need only be held in those GISCs supporting the region or AMDCN for which the information is to be available. This requirement intersects the WIS DAR requirement (see 3.5.6).
Note: The method used in WIS discovery metadata records to identify information intended for global exchange is defined in Appendix C, Part C1, requirement 9.1.1.
3.5.5.2 See also 4.4, WIS-TechSpec-3 (Centralization of globally distributed data), 4.5, WIS-TechSpec-4 (Maintenance of user identification and role information) and 4.6, WIS-TechSpec-5 (Consolidated view of distributed identification and role information).
3.5.6 Discovery, access and retrieval
3.5.6.1 In support of the DAR function, each GISC shall maintain and provide access to a comprehensive catalogue of information across all WMO programmes encompassed by WIS. This includes, but is not limited to, information intended for global exchange. In order to satisfy the DAR functional requirement, GISCs are required to support, in interactive and in batch modes: upload; change and deletion of metadata; user discovery of metadata; user access to metadata; and synchronization of the comprehensive WIS discovery metadata catalogue with other GISCs.
3.5.6.2 See also 4.9, WIS-TechSpec-8 (DAR metadata (WIS discovery metadata) catalogue search and retrieval) and 4.10, WIS-TechSpec-9 (Consolidated view of distributed DAR metadata (WIS discovery metadata) catalogues).
3.5.7 Data network connectivity of a GISC
Each GISC shall provide around-the-clock connectivity to the public and dedicated communication networks at a capacity that is sufficient to meet its global, regional and AMDCN responsibilities. Each GISC should ensure that every telecommunication facility it employs in support of WIS has the appropriate level of availability and capacity, including, as necessary, routing and back-up arrangements. Each GISC should maintain service level agreements with the suppliers of its communication links and associated hardware.
3.95.28 Coordinate telecommunications WIS2 node implementation in a GISC area
Each GISC shall coordinate with the Centres in its area of responsibility the implementation and maintain a WIS2 node systemtelecommunications infrastructure that can meet the WIS2 requirements for information exchange within the area the Goobal services. In the case of particular global and/or regional agreements, a GISC could also support the exchange of agreed WIS time- and operation-critical information with other AMDCNs. The telecommunications infrastructure shall be implemented through various technologies and services (for example, the Internet, satellite-based data distribution, dedicated data networks) in accordance with capacity and reliability requirements.
3.95.39 CAPACITY BUILDING Recovery arrangements of a GISC
3.5.9.1 Each GISC shall provide training sessions to enable all NMHSs under its AoR, particularly from least developed countries and small island developing States, to use the infrastructure and services of the WIS 2.0 platform to build services that meet the needs of their domestic stakeholders. implement and operate proper procedures and arrangements to provide swift recovery or back-up of its essential services in the event of an outage. Each GISC should maintain arrangements for system back-up in case of total site failure (for example, an offsite Disaster Recovery Centre) and for partial back-up in situations otherwise affecting WIS functions within the GISC.
3.5.9.2 Each GISC shall maintain arrangements with one or more back-up GISCs that include, as a minimum, the collection and dissemination of information to/from its AMDCN to be taken up by another GISC in case of an incapacitating system failure.
3.95.410 Performance monitoring of a GISC
3.95.410.1 Each GISC shall participate in monitoring the performance of WIS2 nodes in their area of responsability, including monitoring the collection and distribution of data and products intended for global exchange. Each GISC shall report routinely to other GISCs, as well as to the WMO Secretariat, information concerning the status and performance of connectivity to WIS centres in its area, including capacity and technology used (for example, the Internet, satellite-based data distribution and dedicated data networks). CBS INFCOM shall review and report on the status and performance of GISCs with the assistance of the WMO Secretariat.
3.95.410.2 Each GISC shall in turn and according to the schedule agreed among GISCs take responsibility for monitoring the global operational performance of WIS.
Note: Guidance on how this monitoring should be undertaken is provided in Guide to the WMO Information System (WMO‑No. 1061), Part VIII.
3.95.410.3 Monitoring of the collection and dissemination of WIS information (data and products) should include, as appropriate, WIS monitoring and monitoring related to WMO Programmes.
3.95.410.4 See also 4.16, WIS-TechSpec-15 (Reporting of quality of service).
3.5.11 Coordination of activities between GISCs
GISCs shall participate in an annual meeting to coordinate their activities.
3.106 Functional requirements of a DCPC
610.1 General
Note: The term “information” is used in a general sense and includes data and products.
The specific performance and functional requirements of a particular DCPC shall be determined by the programme it supports. DCPCs that support programmes with mission-critical responsibilities, and especially programmes with safety-of-life missions, shall maintain a high level of operational reliability, including required telecommunications. Each DCPC shall provide metadata describing the information it makes available through the WIS comprehensive catalogue, shall provide access to that information and shall participate in monitoring the overall performance of WIS.
610.2 Collect information from a DCPC area
610.2.1 As appropriate to its programme role, a DCPC shall deploy a WIS2 node to collect information intended for dissemination to NCs GCs, GBs, GDCs and GM within its area of responsibility (that is, regional collections).
610.2.2 See also 4.2, WIS-TechSpec-1 (Uploading of metadata for data and products) and 4.3, WIS-TechSpec-2 (Uploading of data and products).
610.3 Collect programme-related information
3.6.3.1 As appropriate to its programme role, a DCPC shall collect the specific programme-related data and products.
3.6.3.2 See also 4.2, WIS-TechSpec-1 (Uploading of metadata for data and products) and 4.3, WIS-TechSpec-2 (Uploading of data and products).
610.4 Production support of programme-related information
3.6.4.1 As appropriate to its programme role, a DCPC shall provide data management and data communications that are adequate to support the production of regional or specialized data and products.
3.6.4.2 See also 4.2, WIS-TechSpec-1 (Uploading of metadata for data and products) and 4.3, WIS-TechSpec-2 (Uploading of data and products).
610.5 Provide information intended for global exchange
610.5.1 As appropriate to its programme role, each DCPC shall provide notifications and information intended for global exchange to its responsible GISC Global Cache, Global Discovery Catalogue and Global Broker.
610.5.2 See also 4.2, WIS-TechSpec-1 (Uploading of metadata for data and products) and 4.3, WIS-TechSpec-2 (Uploading of data and products).
610.6 Disseminate information
610.6.1 As appropriate to its programme role, each DCPC shall disseminate messages and information other than that intended for global exchange.
610.6.2 See also 4.11, WIS-TechSpec-10 (Downloading files via dedicated networks), 4.12, WIS-TechSpec-11 (Downloading files via non-dedicated networks) and 4.13, WIS-TechSpec-12 (Downloading files via other methods).
610.7 Provide access to information
610.7.1 Each DCPC shall support access to its products via SFTP, HTTPS WMO request/reply (“pull“) mechanisms in an appropriate manner.
3.10.7.2 Each DCPC shall provide Web Accessible Folder (WAF), Message Queuing Protocol (MQP) as required by WIS 2.0 architecture.
3.10.7.3 Each DCPC shall provide Web API based on OGC standards to facilitate access to data using all the software able to connect with this technology
610.7.42 See also 4.5, WIS-TechSpec-4 (Maintenance of user identification and role information), 4.7, WIS-TechSpec-6 (Authentication of a user) 4.8, WIS-TechSpec-7 (Authorization of a user role).
610.8 Describe information with metadata
3.6.8.1 Each DCPC shall describe its data and products according to an agreed WMO metadata standard, provide access to this catalogue of data and products and provide these metadata as appropriate to other centres, in particular a GISC.
3.6.8.2 See also 4.9, WIS-TechSpec-8 (DAR metadata (WIS discovery metadata) catalogue search and retrieval) and 4.10, WIS-TechSpec-9 (Consolidated view of distributed DAR metadata (WIS discovery metadata) catalogues).
610.9 Recovery arrangements of a DCPC
As appropriate to its programme role, each DCPC shall implement and operate proper procedures and arrangements to provide swift recovery or back-up of its essential services in the event of an outage.
610.10 Performance monitoring of a DCPC
3.6.10.1 Each DCPC shall participate in monitoring the performance of WIS.
3.6.10.2 See also 4.16, WIS-TechSpec-15 (Reporting of quality of service).
711 Functional requirements of an NC
711.1 Provide data, products and metadata
3.117.1.1 As required by the Technical Regulations (WMO-No. 49), Volume I, Part II, 1.2.8, each NC shall use WIS2 node to provide data and products, in line with its programme responsibilities. Such data and products shall be provided together with associated WIS2 discovery metadata, in accordance with WIS practices, procedures and specifications.
3.117.1.2 See also 4.2, WIS-TechSpec-1 (Uploading of metadata for data and products) and 4.3, WIS-TechSpec-2 (Uploading of data and products).
3.117.2 Collect programme-related information
3.117.2.1 As appropriate to its programme role, each NC shall collect programme-related data and products.
711.2.2 See also 4.2, WIS-TechSpec-1 (Uploading of metadata for data and products) and 4.3, WIS-TechSpec-2 (Uploading of data and products).
711.3 Production support of programme-related Information
3.7.3.1 As appropriate to its programme role, each NC shall provide data management and data communications that are adequate to support the production of data and products.
711.3.2 See also 4.2, WIS-TechSpec-1 (Uploading of metadata for data and products) and 4.3, WIS-TechSpec-2 (Uploading of data and products).
711.4 Describe information with metadata
711.4.1 Each NC shall describe its data and products according to an agreed WMO metadata standard and provide this information, as appropriate, to the GC and the GDCother Centres.
711.4.2 See also 4.9, WIS-TechSpec-8 (DAR metadata (WIS discovery metadata) catalogue search and retrieval).
3.7.5 Performance monitoring of an NC
3.7.5.1 As required by the Technical Regulations (WMO-No. 49), Volume I, Part II, 1.2.9, each NC shall participate in monitoring the performance of WIS2.
3.7.5.2 See also 4.16, WIS-TechSpec-15 (Reporting of quality of service).