November 2006 TECO-WIS, Seoul 1 Definition of the Internet Network of networks –millions of...
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Transcript of November 2006 TECO-WIS, Seoul 1 Definition of the Internet Network of networks –millions of...
November 2006
TECO-WIS, Seoul 1
Definition of 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 2006
TECO-WIS, Seoul 2
Common 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 GTS
Communication Component
Function
GTS Delivery of time critical communication for weather, water and climate operations
Internet Communication for less critical requirements and possibly for large volumes of data
November 2006
TECO-WIS, Seoul 3
Telecommunication Options
BROADCASTNETWORK
GTS
INTERNET
CENTER B
OTHER NON-GTS LINKS
CENTER A
INTERNET
November 2006
TECO-WIS, Seoul 5
Virtual Private Networks (VPN)
Create the equivalent of a dedicated private link using the Internet as a connection media
CENTER A
PUBLIC SUBNET
GTS
INTERNET
WORKSTATION 1
WORKSTATION 2
WAFS RECEIVER
DIGITAL VIDEO BROADCAST
RECEIVER
INTERNAL ROUTER / FIREWALL
MESSAGE SWITCHING SERVER
1
MESSAGE SWITCHING SERVER
2
ACCESS DEVICE ROUTER / FIREWALL
VPN INTERFACE
DMZ SUBNET
INTERNAL PROTECTED
SUBNET
OTHER SYSTEMS
ACCESS DEVICE ROUTER / FIREWALL
FIREWALL
LINK PROVIDED BY TELECOM SUPPLIER
LINK PROVIDED BY INTERNET SUPPLIER
WEB PORTAL / SERVER 1
WEB PORTAL / SERVER 2
TYPICAL VPN OVER INTERNET CONNECTIONAND
November 2006
TECO-WIS, Seoul 6
WIS VPN Pilot Project in Regions II and V (as of Sept 2006)
Hong Kong
India
Iran
Korea
Oman
Saudi Arabia
Vietnam
Australia
Brunei
Malaysia
New Zealand
China
Soon established VPN-link with Japan
Established VPN-linkwith Japan
Japan
Singapore
10Mbps (max)
2Mbps
4Mbps
512Kbps
2Mbps
1Mbps
100Mbps (max)
3Mbps
2Mbps
2Mbps
1MbpsInternet
100Mbps (max)
100Mbps (max)
256Mbps (min)- 440Mbps
(max)
November 2006
TECO-WIS, Seoul 7
File 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.15
November 2006
TECO-WIS, Seoul 9
Electronic 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
– Spamming is the abuse of electronic messaging systems to send unsolicited, undesired bulk messages
November 2006
TECO-WIS, Seoul 10
Email Implementation
CENTER A
PUBLIC SUBNET
GTS
INTERNET
WORKSTATION 1
WORKSTATION 2
WAFS RECEIVER
DIGITAL VIDEO BROADCAST
RECEIVER
INTERNAL ROUTER / FIREWALL
MESSAGE SWITCHING SERVER
1
MESSAGE SWITCHING SERVER
2
ACCESS DEVICE ROUTER / FIREWALL
VPN INTERFACE
DMZ SUBNET
INTERNAL PROTECTED
SUBNET
EMAILSERVER
ACCESS DEVICE ROUTER / FIREWALL
FIREWALL
LINK PROVIDED BY TELECOM SUPPLIER
LINK PROVIDED BY INTERNET SUPPLIER
WEB PORTAL / SERVER 1
WEB PORTAL / SERVER 2
TYPICAL EMAIL SERVER EXCHANGES
VIRUS & SPAM
FILTERS
TYPICAL EMAIL USER EXCHANGES
November 2006
TECO-WIS, Seoul 11
Web 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 complex
November 2006
TECO-WIS, Seoul 12
Web Server Implementation
CENTER A
PUBLIC SUBNET
GTS
INTERNET
WORKSTATION 1
WORKSTATION 2
WAFS RECEIVER
DIGITAL VIDEO BROADCAST
RECEIVER
INTERNAL ROUTER / FIREWALL
MESSAGE SWITCHING SERVER
1
MESSAGE SWITCHING SERVER
2
ACCESS DEVICE ROUTER / FIREWALL
VPN INTERFACE
DMZ SUBNET
INTERNAL PROTECTED
SUBNET
OTHER SYSTEMS
ACCESS DEVICE ROUTER / FIREWALL
FIREWALL
LINK PROVIDED BY TELECOM SUPPLIER
LINK PROVIDED BY INTERNET SUPPLIER
WEB PORTAL / SERVER 1
WEB PORTAL / SERVER 2
TYPICAL WEB SERVER ACCESS
November 2006
TECO-WIS, Seoul 13
Important Documents
http://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)