1. Slide 1 ET-CTS - GISC Network Bandwidth RequirementsSlide 1 GISC network bandwidth requirements A proposed method for an educated guess… Hiroyuki Ichijo – JMA Rémy Giraud - ECMWF ET-CTS Co-Chairs

2. Slide 2 ET-CTS - GISC Network Bandwidth RequirementsSlide 2 Introduction As part of the requirements of the WIS, each GISC must: host a Discovery, Access and Retrieval (DAR) catalogue hold and distribute at least 24 hours of current WMO data and products intended for global distribution. Each GISC is responsible for coordinating with the Centres within its area of responsibility a WIS telecommunications infrastructure that can meet the WIS requirements for information exchange within the area and that can exchange agreed WIS time critical and operational critical information. The WIS real-time network would be composed of a small number of Area Meteorological Data Communication Networks (AMDCNs) and a WIS core network interconnecting the GISCs and AMDCNs together. GISCs would be responsible for ensuring that their AMDCNs are developed and maintained and, where the appropriate agreements are in place, the traffic between WIS centres in different AMDCNs is managed. [extract from CBS-XIV Abridged final report ]

3. Slide 3 ET-CTS - GISC Network Bandwidth RequirementsSlide 3 Main task Required GISC bandwidth on the core network should be considered carefully considering not only bulk but also peak traffic. In addition, it is important to study smooth evolution process in gradual participation of operational GISCs. Background for consideration (1) The Improved MTN (IMTN) project started at ET-IMTN meeting in Sep/Oct 1999. Its implementation has progressed in technical evolution process as the configuration of two clouds (i.e. Network I & Network II) until Sep 2009. By the end of 2009, all links via Network I have migrated to via Network II. Currently the IMTN is operating on a single coordinated MPLS cloud. Since a WIS core network will be established on the IMTN, it is easy to realize the full-mesh GISC topology. However it is expected that traffic on the WIS core network handled by GISCs will considerably increase. To support future-oriented WIS operation, network capacity of each GISC will have to be expanded in collaboration with others.

4. Slide 4 ET-CTS - GISC Network Bandwidth RequirementsSlide 4 Background for consideration (2) Appropriate maximum number of GISCs has come up for discussion repeatedly since the initial stage called as FWIS: [Extraction from the final report of CBS-ext.02, Annex IV] Several (perhaps four to 10) centres would serve as GISCs. Each GISC would have a defined area of responsibility. GISCs would usually be located within or closely associated with a centre running a global data assimilation system or having some other global commitment, such as a WMC. [Extraction from ET-CTS outcome reported to ICG-WIS-3 in 2006] Correlation between the number of GISCs and reasonableness of full-mesh topology of a WIS core network: From the practical and relative evaluation, the full-mesh can be appropriate on the assumption that the number of GISCs would be less than 7 inclusive. In case of more GISCs, the full-mesh should be avoided. However 13 GISCs candidates have been identified as of the end of November 2009. Sense of a possible basis Further study is desired to clarify the appropriate maximum number of GISCs from the practical view of network bandwidth requirements.

5. Slide 5 ET-CTS - GISC Network Bandwidth RequirementsSlide 5 Hypothesis (1) Flows Each GISC will receive data from its area of responsibility on an AMDCN A backup GISC should be available to receive data from Centres from another AMDCN All GISCs will be linked directly each other (i.e. mesh-topology) Each GISC will push all data received to all other GISCs Not all AMDCN will provide the same amount of data. (i.e. unbalanced model)

6. Slide 6 ET-CTS - GISC Network Bandwidth RequirementsSlide 6 Hypothesis (2) Technical A WIS core network to link all GISCs will not be based on multi- cast but uni-cast mechanism for, at least, initial implementation All network protocol have an overhead. A 20% overhead is a typical value for FTP Despite control, there will be duplicated data over the network. In order to define the bandwidth requirements, it will be necessary to estimate: Daily data volume to be sent and received Estimate of peak rates if the data transfers are not evenly spread over the 24 hours.

7. Slide 7 ET-CTS - GISC Network Bandwidth RequirementsSlide 7 Points to study (1) The required bandwidth for each GISC will depend on: The total number of GISCs The estimated amount of data to be transferred daily by each GISC The potential peaks of traffic within the 24 hours period The traffic repartition between AMDCN: An unbalanced traffic pattern between the GISCs will have a lot of impact The protocols used on the network and their overhead Thus we should: i) estimate data volume for global exchange more practically; ii) develop a matrix sheet to indicate bandwidth requirements in each case; iii) recommend an appropriate maximum number of GISCs if possible.

8. Slide 8 ET-CTS - GISC Network Bandwidth RequirementsSlide 8 Points to study (2) An online spreadsheet available at http://spreadsheets.google.com/ccc?key=0AsDEZG6XKnasdG9MNWlRYXUzeVJJRkJsWFppWlI0UEE&hl=fr Is a tool to be used to automate some calculation for the bandwidth. Based on values to be defined online by the user, it is then possible to estimate the required bandwidth. To access this document a freely available Google account is required Please use Sheet Comments and History to add comments and suggestions to improve the spreadsheet.

9. Slide 9 References and hints

10. Slide 10 ET-CTS - GISC Network Bandwidth RequirementsSlide 10 IMTN evolution Exeter Sofia Melbourne Buenos Aires Tokyo Beijing Nairobi Washington Network I Jeddah Prague Toulouse Dakar Algiers Offenbach Brasilia Cairo New Delhi Moscow Network II

11. Slide 11 ET-CTS - GISC Network Bandwidth RequirementsSlide 11 WIS multicast network Internet IGDDS,etc Full-mesh topology of WIS core network Full-mesh topology will bring two benefits: (1) maximum redundancy in the configuration of GISC backup channels; (2) operational simplicity in data synchronization GTS IMTN WIS core network More than 180 centers Max 18 centers Less than 13 centers AMDCN Conceptual interrelation between GTS and WIS networks DAR AMDCN

12. Slide 12 ET-CTS - GISC Network Bandwidth RequirementsSlide 12 AMDCN Priorities of study for bandwidth requirements WIS core network AMDCN GISC Internet IGDDS,etc DAR First priority Second priority Third priority Target in this period

13. Slide 13 ET-CTS - GISC Network Bandwidth RequirementsSlide 13 Architecture and flows

14. Slide 14 ET-CTS - GISC Network Bandwidth RequirementsSlide 14 Balanced model (4 GISCs case) WIS core network (Full-meshed topology) Responsible area #1 AMDCN #1 GISC #1 2GB Responsible area #2 AMDCN #2 GISC #2 2GB Responsible area #3 AMDCN #3 GISC #3 2GB Responsible area #4 AMDCN #4 GISC #4 2GB Incoming daily volume Outgoing daily volume Necessary port speed GISC #1 6 GB Bandwidth appropriate for 6GB/day GISC #2 ditto GISC #3 ditto GISC #4 ditto Example case of total volume of 8GB

15. Slide 15 ET-CTS - GISC Network Bandwidth RequirementsSlide 15 WIS core network (Full-meshed topology) Responsible area #1 AMDCN #1 GISC #1 5GB Responsible area #2 AMDCN #2 GISC #2 1GB Responsible area #3 AMDCN #3 GISC #3 Responsible area #4 AMDCN #4 GISC #4 1GB 5GB 1GB 5GB 1GB Unbalanced model (4 GISCs case) Incoming daily volume Outgoing daily volume Necessary port speed GISC #1 3 GB15 GB Bandwidth appropriate for 15GB/day GISC #2 7 GB3 GB Bandwidth appropriate for 7GB/day GISC #3 ditto GISC #4 ditto Example case of total volume of 8GB

16. Slide 16 ET-CTS - GISC Network Bandwidth RequirementsSlide 16 Reference to volume required (1) Average daily volume received at RTH Washington: 26.66 GB (as of May 2008) Volume received by Protocol

17. Slide 17 ET-CTS - GISC Network Bandwidth RequirementsSlide 17 Reference to volume required (2) Volume transmitted by Protocol Average daily volume transmitted from RTH Washington: 30.81 GB (as of May 2008)

18. Slide 18 ET-CTS - GISC Network Bandwidth RequirementsSlide 18 Reference to volume required (3) Results of RTH data survey 1 August 2007 Extract from ICG-WIS IV (31.VIII.2007) /Doc. 3.1(1) http://www.wmo.int/pages/prog/www/ISS/Meetings/ICG-WIS_ECMWF2007/documents/RRR-Doc3-1-1.doc

19. Slide 19 ET-CTS - GISC Network Bandwidth RequirementsSlide 19 Reference to volume required (4) Past and projected data volumes (RTH-C) Extract from ICG-WIS IV (31.VIII.2007) /Doc. 3.1(1) http://www.wmo.int/pages/prog/www/ISS/Meetings/ICG-WIS_ECMWF2007/documents/RRR-Doc3-1-1.doc