Definition of the Internet

November 2006TECO-WIS, Seoul1Definitionof the Internet•Network of networks–millions of smaller domestic, academic, business, and government networks–Uses TCP/IP protocol suite•Carries various information and services, such as electronic mail, online chat, file transfer, documents of the World Wide Web.•Internet and the World Wide Web are not synonymous:–the Internet is a collection of interconnected computer networks, linked by telecommunication media–the Web is a collection of interconnected documents, linked by hyperlinks and URLs.November 2006TECO-WIS, Seoul2Common Protocols allow Coexistence•Internet can be used as:–an underlying technology for some components of the GTS in special conditions–as a backup to the GTS–as a complement to the GTSCommunication ComponentFunctionGTSDelivery of time critical communication for weather, water and climate operationsInternetCommunication for less critical requirements and possibly for large volumes of dataNovember 2006TECO-WIS, Seoul3Telecommunication OptionsBROADCASTNETWORKGTSINTERNETCENTER B OTHER NON-GTS LINKS CENTER AINTERNETNovember 2006TECO-WIS, Seoul4VPN ConceptVPN CLIENTVPN SERVERINTERNETNovember 2006TECO-WIS, Seoul5Virtual Private Networks (VPN)Create the equivalent of a dedicated private link using the Internet as a connection mediaCENTER APUBLIC SUBNETGTSINTERNETWORKSTATION 1WORKSTATION 2WAFS RECEIVERDIGITAL VIDEO BROADCAST RECEIVERINTERNAL ROUTER /FIREWALLMESSAGE SWITCHING SERVER 1MESSAGE SWITCHING SERVER 2ACCESS DEVICE ROUTER /FIREWALLVPN INTERFACEDMZ SUBNETINTERNAL PROTECTED SUBNETOTHER SYSTEMSACCESS DEVICE ROUTER /FIREWALLFIREWALLLINK PROVIDED BY TELECOM SUPPLIERLINK PROVIDED BY INTERNET SUPPLIERWEB PORTAL /SERVER 1WEB PORTAL /SERVER 2TYPICAL VPN OVER INTERNET CONNECTIONANDNovember 2006TECO-WIS, Seoul6WIS VPN Pilot Project in Regions II and V (as of Sept 2006)Hong KongIndiaIranKoreaOmanSaudi ArabiaVietnamAustraliaBruneiMalaysiaNew ZealandChinaSoon established VPN-link with JapanEstablished VPN-linkwith JapanJapanSingapore10Mbps (max)2Mbps4Mbps512Kbps2Mbps1Mbps100Mbps (max)3Mbps2Mbps2Mbps1MbpsInternet100Mbps (max)100Mbps (max)256Mbps (min)-440Mbps (max)November 2006TECO-WIS, Seoul7File Transfers and FTP servers•Uses File Transfer Protocol•Can be used for dissemination or exchange of bulk meteorological data through Internet, GTS or other local/wide area networks•Recommended for predefined users•Efficient data exchange protocol•Good for both push and pull configurations•File Naming is important –see Man 386 Att II.15November 2006TECO-WIS, Seoul8FTP Server ImplementationNovember 2006TECO-WIS, Seoul9Electronic Mail•Uses the Simple Mail Transfer Protocol (SMTP)•Complementary method of data input into the GTS–Should not be used to replace GTS data exchanges for mission critical components–Usually can not guarantee real time data delivery–Requires sites to collect messages (some examples: Washington, New Zealand, Tokyo, Beijing)–Requires a strong quality control at the collecting center as the collected messages often contain several typing or format mistakes•Mostly a push mechanism•May be used for notification (for example that a file is available for delivery while the file itself is placed on an FTP server)•Excellent general communication tool•Important entry point for virusses, worms and Trojan Horses•Must deal with SPAM problem–Spammingis the abuse of electronic messaging systems to send unsolicited, undesired bulk messages November 2006TECO-WIS, Seoul10Email ImplementationCENTER APUBLIC SUBNETGTSINTERNETWORKSTATION 1WORKSTATION 2WAFS RECEIVERDIGITAL VIDEO BROADCAST RECEIVERINTERNAL ROUTER /FIREWALLMESSAGE SWITCHING SERVER 1MESSAGE SWITCHING SERVER 2ACCESS DEVICE ROUTER /FIREWALLVPN INTERFACEDMZ SUBNETINTERNAL PROTECTED SUBNETEMAILSERVERACCESS DEVICE ROUTER /FIREWALLFIREWALLLINK PROVIDED BY TELECOM SUPPLIERLINK PROVIDED BY INTERNET SUPPLIERWEB PORTAL /SERVER 1WEB PORTAL /SERVER 2TYPICAL EMAIL SERVER EXCHANGESVIRUS & SPAM FILTERSTYPICAL EMAIL USER EXCHANGESNovember 2006TECO-WIS, Seoul11Web Servers•Based primarily on Hyper Text Transfer Protocol (HTTP)•Used to make available various data and reports, available to users who request the information by downloading the various «web pages» (pull mechanism)•Offers an intuitive approach to presentation of data and links between data elements•Allows complex scripts and data management tools to be added•Requires permanent connection to the Internet•Requires careful and significant planning and maintenance–Weather data is updated very often–Demand for weather data can be very high–In large sites can become very complexNovember 2006TECO-WIS, Seoul12Web Server ImplementationCENTER APUBLIC SUBNETGTSINTERNETWORKSTATION 1WORKSTATION 2WAFS RECEIVERDIGITAL VIDEO BROADCAST RECEIVERINTERNAL ROUTER /FIREWALLMESSAGE SWITCHING SERVER 1MESSAGE SWITCHING SERVER 2ACCESS DEVICE ROUTER /FIREWALLVPN INTERFACEDMZ SUBNETINTERNAL PROTECTED SUBNETOTHER SYSTEMSACCESS DEVICE ROUTER /FIREWALLFIREWALLLINK PROVIDED BY TELECOM SUPPLIERLINK PROVIDED BY INTERNET SUPPLIERWEB PORTAL /SERVER 1WEB PORTAL /SERVER 2TYPICAL WEB SERVER ACCESSNovember 2006TECO-WIS, Seoul13Important Documentshttp://www.wmo.int/web/www/documents.html•Manual 386, Attachment II.15 –Use of TCP/IP on the GTS (Revision 3, Sept 2006)•Guide on Information Technology Security (Sept 2006)•Guide on Internet Practices (Sept 2006)•Guide on use of FTP and FTP servers at WWW centres (Sept 2006)•Guidance on IPSec-based VPNs over the Internet (April 2004)