et-cts-2010-report
Table of contents
- 1. Organization of the meeting
- 2. RTH status reports
- 3. Recommended practices for data communication techniques and procedures.
- 4. Review and develop updates to recommended practices for data-communication and data access procedures
- 5. Review of guidance materials for implementation of data communication facilities at www centers
- 6. Develop the organization and design principles for the WIS data communication structure, and related consideration matter
- 6.1. Review and further develop the organizational and design document for WIS data communication structure.
- 6.2. Report on the consolidation of two IMTN clouds.
- 6.3. Study the reasonable maximum number of GISCs from the view of necessary bandwidth based on estimate traffic volume.
- 6.4. Develop a list of synchronization protocols among GISCs
- 6.5. Guidance on administrative and contractual aspects of data communication services for WIS implementation.
- 7. WIS Plan and Roadmap
- 8. AoB
- 9. Closure.
1. Organization of the meeting
1.1. Opening
The fourth session of the Expert Team on Communication Techniques and Structure (ET-CTS) was held in Geneva from 21-24 October 2010, under the chairmanship of Mr. Hiroyuki Ichijo.1.2. Welcome
Mr. Peiliang Shi, Director of WIS, welcomed the participants, noting that the new team at the secretariat was taking over the ET-CTS and still catching up. He pointed out that he was looking forward to working with the group, adding that, having been an active member of the group itself before joining the secretariat, seeing new and old participants was especially heartwarming.1.3. Agenda
The meeting adopted the provisional agenda as reproduced at the beginning of this report, pointing out that it would not be worked through chronologically but in order of priorities and to accommodate the joint session with the Expert Team on WIS-GTS Operation and Implementation (ET-OI). The RTH status reports were split over Tuesday 21th and Tuesday 23th morning, serving as warm-up for the more tough discussions ahead. Bearing in mind these, and the full schedule, the meeting agreed on a 9-12.30h and 2-5.30h schedule upon suggestion of the Chairman. Concerning the priorities, the Chairman pointed out that the agenda point 5.4 was of special importance, not having been touched over the previous years and that he expected tough discussions on agenda point 6.3, since the number of GISCs was a “hot potato”. Mr. Remy Giraud, Co-Chair, pointed out that on many issues the boundaries between the ET-CTS and the ET-OI were not clear, reinforcing the need for a joint session. Finally, on suggestion of Mr. Ashgar Noor, representative of the US, a discussion of the role of social networks for meteorological services was added to point 8.2. RTH status reports
2.1. RTH Offenbach.
Ms. Ilona Glaser from DWD told the meeting that most of RTH Offenbach’s links to its partners were now realized using the RMDCN, with the internet serving as backup in case of non-availability of the RMDCN, and pointed out that FTP was the main means of file transfer. The meeting then discussed the connectivity between RTH Offenbach and RTH Tehran noting that in DWD’s opinion the occasional connectivity issues had their origin outside RTH Offenbach’s systems and, the internet being the means of realizing the connection, not much could be done. On the link to Nairobi, the meeting learned that communication was smooth as long as a VPN connection can be established, but that there seemed to be frequent VPN service outages attributed to a recent VPN provider switch in Nairobi. Finally, the meeting noted that RTH Offenbach’s GTS link with RTH Jeddah was now also realized using the Internet and that connectivity was still smooth, apart from occasional troubles. (also see RMDCN status)2.2. RTH Melbourne.
Mr. Ian Senior from BoM informed the meeting that the GTS status at RTH Melbourne was generally stable, but that there were reliability issues with the links to Jakarta and the Maldives. He informed the meeting of a mayor incident, in which an unnamed country had accidentally re-introduced old GTS messages into the system and explained that since there was no month field in the GTS, other countries failed to detect that these were old messages. He continued that the issue was exacerbated by the fact that the messages did not pertain to the country in question but were messages from other countries. On changes in the 2008-2010 period, he explained that the mayor changes had been the retirement of the old frame relay links to Washington, Tokyo, Exeter and Jakarta which had been replaced by connections to the RMDCN and SingTel MPLS connections respectively. He told the participants that the other regional links were also progressively being migrated to this AMDCN and that this constituted a mayor improvement noting the greater bandwidth and reliability. He reminded the meeting of the limits of the GTS, notably the lack of subscription services, a catalogue and the struggle of having to handle three types of data (model, satellite and warnings) and a lack of a mechanism to request additional data on-line, but pointed out that these issues would eventually be resolved by WIS. He recommended that the following points in the filename convention be addressed at some stage: upper-case only data, limitation of character length to 69 and need to end all lines with two carriage returns and a line feed, with a view of not limiting new protocols and codes. The meeting was supportive of removing these limitations and asked the WMO secretariat to consider disseminating a questionnaire to members to find out more about operational problems.2.3. RTH Tokyo.
Mr. Kenji Tsunoda (AKA Ken) from JMA informed the participants of the progress made in the 2008-2010 period. Under the auspices of JMA and operated by NTT, a new MPLS based region II AMDCN had been created replacing the old frame-relay based network which was discontinued in 2009. In the same year, JMA also established a new link with Exeter via the RMDCN and participated in the migration from the old cloud I frame-relay network provided by British Telecom to the RMDCN. He pointed out that RTH Tokyo had two load-shared 3Mbit/s connections to the RMDCN, bringing its total theoritical speed under normal operation conditions to 6Mbit/s. The participants expressed interest in the implementation of RTH Tokyo’s messages switching and learned that JMA was striving to use FTP only, and to use a single-file approach for urgent messages and had different switching systems for FTP and sockets. It also understood that the maximum filesize at JMA is an easy to extend 2GB, which leaves plenty of room to accumulate messages, the message size being limited to 500kb. The meeting also discussed the contractual setup of the Region II AMDCN, summarized under agenda point 6.5.2.4. NMC-RSMC Montreal.
Mr. Jean-François Gagnon from Environnement Canada reminded the participants that Montreal was not an RTH, not part of any cloud and only had one official GTS link, via TCP/IP, to WMC Washington and an unofficial link to Exeter, with plans to connect to other RTHs in the medium-term. He informed the meeting of plans to upgrade both connections but pointed out that it did not seem viable to put all the traffic into the GTS, since the cost of this would be prohibitive. Reinforcing this argument, he remarked that much of Canada’s traffic was not inserted into the GTS but travels through the internet instead without problems. The meeting noted that FTP was used for the connections with Washington, USA-NEP and USA-NESDIS. Regarding the development of WIS, he informed the meeting that Canada was planning to be a NC and DCPC but that it had been difficult to get the necessary developments launched internally due to internal changes. He took a positive view of future WIS developments, since he had observed more WIS related activity lately.2.5. ASECNA (Region I)
Mr. Ayina Hugues from ASECNA briefed the meeting on activities in the region. The participants noted that ASECNA had established two new GTS links with Toulouse and Dakar via VSAT and that the links with Njamina and Brazzaville had been migrated to TCP/IP. The meeting learned that ASECNA was in the process of establishing backup links with TCP/IP VPNs for the other ASECNA countries and that there were now no GTS X.25 links left. He continued that ASECNA policy was to migrate all GTS channels to TCP/IP and to use IPSEC based VPNs over the internet as backup. Newly established channels will use VPNs over the internet as main connection. The links to Toulouse are established via VSAT and IP, whereas the inner-toulouse connection between ASECNA and Meteo France was implemented with a cisco phylone radio. He also announced that the implementation of computerized systems was progressing thanks to innovative technologies such as GSM interfaces and solar panels. The meeting also learned that email was used to collect AMDAR aircraft observations. (XXX: check.. does that make sense?). Regarding WIS implementation plans, the participants noted that MTN member Dakar and Brazzaville will be DCPCs and that Dakar might be nominated as a regional GISC, depending on further political discussions in the region. The participants praised the work of ASECNA and the technological advances in the region, especially the innovations in IPv6, GSM and portable devices not seen in other regions.2.6. WMC Washington:
Mr. Ashgar Noor from NWS/NOAA briefed the meeting that the US had improved the switching in its backbone and had now completely removed single points of failure, since all connections were redundant. The meeting noted that the US had increased the size of the cache of outgoing products and messages so that files as long as 10 days back can now be retrieved and examined. The participants learned that ECMWF had pointed out to NWS/NOAA the issue of the RMDCN connection in New York, which apparently constitutes a single point of failure in the connection to the RMDCN.2.7. RTH Bunos Aires.
Mr. Jose Luis Gianni from RTH Buenos-Aires (Argentina) told the participants that the regional systems had for many years relied on VSAT,X.25 and IP, but that users were increasingly complaining about low speeds, however, upgrades were expensive. The goal was to move the network to a MPLS based one, but that the contract had been delayed because of a political decision to move the Headquarters to a new location, which was unfortunately lacking telecommunications facilities. Regarding the contact with INMET (Brazil), the meeting learned that Argentina was supportive of INMETs becoming a GISC. The participants noted the difficulties in the region to establish an AMDCN and were happy to learn that an Internet and VPN based network had been created using OpenVPN, noting the simplicity of usage and technical feasibility of any-to-any connectivity and now widely usage of FTP. Argentina’s last X.25 connection with Chile and the slow connection with Brasilia would also soon be replaced by OpenVPN links. The meeting expressed interest in the availability figures of the OpenVPN based AMDCN, noting that comparison with figures from other regions would be difficult due to regional differences. The particiants noted that Argentina switched its message switching systems to Moving Weather (IBL), using TCP/IP and a30Mbit/s internet connection. The meeting also noted that email was used to collect land and sea-based observations and to disseminate non-commercial and commercial products as well as to provide public services, and that it also served as backup for GTS links. Regarding the implementation of WIS, Argentina nominated 5 DCPCs and would focus on technical assistance to the region, leveraging its Geonetwork skills and relations with Brazil, as well as making sure the IBL technology likely to be employed by Brasilia would work throughout Argentina. The meeting learned that a lack of skilled staff was becoming a serious problem, especially as operations are moved from ICAO (airports) to the NMC.2.8. the GTS and the Internet
During the status reports the meeting repeatedly discussed the role of the GTS and the Internet, summarized here as a separate agenda point. The meeting noted that the GTS was currently used to transport both high-priority and low-priority data, but that there was no clear distinction between essential / operational and the other data in the system noting the different meaning of the GTS in different communities. It also pointed out the twofold role of the Internet in the GTS, since the internet is both used as a GTS link and as a way to transport data outside the GTS. It observed that these distinctions would become less clear in the future since WIS constitutes an umbrella for any data communication. However, the meeting also noted that congress emphasized the importance of the GTS and its continuous and stable improvement. The meeting noted that the usage of the internet varied from region to region and that while only serving as backup in some regions, the Internet had become the main communication tool in Region I due to lack of other communication links, and an important, flexible and cost effective means of data transportation in other regions, notably Region III. The participants noted a need to balance the policy vis a vis the usage of the internet, bearing in mind that performance requirements vary from region to region. The meeting noted that there was uncertainty if a new interpretation of the historical rule of the internet as a suitable link in the absence of other technologies was needed and that it might be worth considering to use the GTS for high-priority messages only and to encourage the usage of the internet for high-volume low priority data.3. Recommended practices for data communication techniques and procedures.
3.1. Development of Guidance on “push” and “pull” technologies for use in WIS.
The meeting struggled to define the exact scope of this point and there was a feeling that there was an overlap with agenda points 4.1 and 6.4. The respective discussion is summarized in the corresponding agenda points. The meeting identified the main scope of the discussion related to this agenda point to be data exchange between WIS centers, and proposed to treat the outreach to a larger user community, a task mainly pertaining to NCs, to agenda point 8. The meeting noted that in WIS there was two types of data transfer, the traditional GTS message flow and 24h essential data cache on one hand and the uploading of metadata records to the GISCs and the synchronization of the metadata catalogue on the other hand. It noted that each had different requirements, especially regarding timely exchange, requiring a different set of technologies. Regarding the synchronization of the 24h “cache”, the requirement of a GISC to store the set of date intended for global exchange for 24 hours, the participants decided that this would be implemented by changing the GTS routing tables so that every GISC receives all messages from its area of responsibility. The synchronization with the other GISCs would be realized by sending these messages to all other GISCs. Duplication would be avoided by not re-sending a message if it is received from another GISC. Synchronization and uploading of the metadata is covered under agenda point 6.4.3.2. Review of the status and advice on adoption of IPv6.
The participants were briefed on the history of IPv6, a short summary of its main features and the current global adoption of IPv6, as well as IPv6 studies conducted by various sites (ECMWF, ASECNA). The meeting noted that IPv6 support with vendors was now very good, and that adoption with providers, although not users, was now considerable. However, it noticed that there was no reason warranting a quick migration of the GTS to IPv6, since there was no tangible business case for WMO. It expected introduction to be gradual with no sense of urgency currently not needing a centrally coordinated migration. The participants learned that address shortage in Region I might lead to a more quick adoption of IPv6 there. The meeting decided to create an IPv6 task-team and tasked it with considering future implementation strategies and migration plans for IPv6 as well as identifying IPv6 business cases for NMHSs. It also decided to develop IPv6 guidelines, maintained collaboratively in the WISWIKI.4. Review and develop updates to recommended practices for data-communication and data access procedures
4.1. Study procedure for priority messages (e.g. tsunami warnings) (GTS and WIS).
The meeting noted that WMO requirement is to deliver high-priority messages within 2 minutes within the GTS but that the current manual on the GTS could lead to transmission times longer than 2 min between GISC nodes. It noticed that the speed of delivery of priority messages in the GTS depends on two factors. First, the topology of the network, since each additional message switch along the route adds an additional delay. Second, the implementation of the message switch, the main issue being the time a message remains queued before being transmitted to the next hop. On the first point the meeting observed that the introduction of WIS would gradually remove the number of hops, since the WIS architecture envisages a hierarchical flow of messages from the AMDCN to the GISC, leading to a more flat structure. On the second point, the meeting decided to change the manual in the GTS so that message switches are required to transmit an incoming message no later than 15 seconds after reception. It also recommended that the sending centre keep the FTP session connected for 10 minutes or until the connection had been idle for 2 minutes.4.2. Blog technologies.
The meeting learned about studies at JMA of blog technologies and noted that blog technologies did not constitute a suitable means for WIS Part A, mainly due to the pull character of the technologies involved. On the other hand, blog technologies are useful for reaching out to a large audience in the internet and could thus be used for telling users both about availability of new products and messages.It recommended that blog technologies continue to be studied in the view of WIS Part B and summarized as a guide which may be contributed to the Guide on Internet Technologies.