CAPÍTULO II: MARCO TEÓRICO
2.4. SALUD AMBIENTAL
2.5.1. CALIDAD DE VIDA
By the mid to late 1990s, the relationship between JANET and SuperJANET was clear. JANET was the UK’s national academic network which linked a diverse range of institutions and organisations.
144
See JANET: Advancing and Supporting the UK’s Education and Research Network, UKERNA, 2003, Available from: http://www.ja.net/documents/JANET_booklet_4_03.pdf, Accessed on: 2 February 2004, Regional Networks, UKERNA, 2001, Available from: http://www.ja.net/janet- sites/MANs, Accessed on: 17 August 2004, and Appendix G.
145
The Networking Programme Report 1994-1995, p. 19.
146
Commissioning the SDH Network, UKERNA, 1995, Available from:
http://www.ja.net/documents/reports/summer95.html, Accessed on: 11 May 2004.
147
SuperJANET ATM Development, UKERNA, 1996, Available from:
http://www.ja.net/documents/UKERNA_News/1996/october/UKERNA_News.html, Accessed on: 11 May 2004.
148
See External Network Access Provision and Transmission, UKERNA, 1996, Available from: http://www.ja.net/documents/UKERNA_News/1996/october/UKERNA_News.html, Accessed on: 11 May 2004 and Upgrade to Bandwidth Between JANET and the UK Commercial IP Providers, UKERNA, 1997, Available from:
http://www.ja.net/documents/UKERNA_News/1997/february/UKERNA_News2.html, Accessed on: 11 May 2004.
8
Key
1. South West England Regional Network (SWERN) 2. Learning Network South East (LeNSE)
3. London Metropolitan Network (LMN) 4. Kentish MAN
5. South Wales MAN 6. Midlands MAN (MidMAN)
7. East of England Regional Network (EastNet) 8. North Wales MAN
9. Greater Manchester Information Network Group (GMING) 10. East Midlands MAN (EMMAN)
11. Net North West (NNW)
12. Yorkshire and Humberside MAN (YHMAN) 13. Cumbria and North Lancashire MAN (C&NLMAN) 14. North East MAN (NorMAN)
15. Clyde Area Network (Clydenet)
16. Edinburgh and Stirling MAN (EaStMAN) 17. Fife and Tayside MAN (FaTMAN)
18. University of the Highlands and Islands Network (UHI Network) 19. Aberdeen MAN (AbMAN)
Figure 3.9. The Regional Networks in 2004.149
149
The actual geographical areas covered by the networks are, of course, larger than the ellipses shown in the figure. UKERNA originally referred to the Regional Networks as MANs.
1 2 3 4 7 6 5 8 9 10 12 13 14 15 16 17 19 11 18 = Regional Network
8 1 2 5 6 8 3 4 7 9 10 12 11 13 14 15 Figure 3.10. SuperJANET II in 1996.150
SuperJANET provided the backbone network to support JANET. Having established SuperJANET II, plans began for the next phase which would consolidate the work of the second stage of developments, while upgrading the speed of the network and rationalising the use of the technologies employed throughout the backbone. The JISC awarded a contract for SuperJANET III to Cable & Wireless, which then replaced the
150
For clarity, the figure only shows 15 SDH sites, which were present in March 1996. The figure therefore does not show the complete SuperJANET topology.
Key 1. Cardiff 2. RAL 3. UCL 4. ULCC 5. Imperial College 6. Cambridge 7. Birmingham 8. Daresbury 9. Nottingham 10. Manchester 11. Leeds 12. Belfast 13. Newcastle 14. Glasgow 15. Edinburgh 34 Mbps SDH circuit
core of the network with new 155 Mbps circuits.151 These circuits interconnected four sites which the company owned. From these nodes, Cable & Wireless established 34 and 155 Mbps links to institutions via Backbone Edge Nodes (BENs) located at universities such as ULCC, Birmingham, and Newcastle. These nodes interconnected the SuperJANET backbone to the Metropolitan Area Networks (see Figure 3.11).152 While this company managed the network, under a Service Level Agreement (SLA), UKERNA managed the edge nodes, with the regional universities overseeing the MANs. The SuperJANET backbone interconnected most institutions, but some still used either SMDS or leased lines to connect to the network. The use of the edge nodes and MANs extended SuperJANET to all institutions and did so economically, using the infrastructure to diffuse bandwidth effectively throughout the country. With the establishment of SuperJANET III during 1998, UKERNA planned to remove SMDS from the network, creating an SDH-only network, over which TCP/IP applications would continue to run.153
By the end of 1999, UKERNA had started to plan the fourth phase of SuperJANET. As the network would not become operational until, perhaps, 2001, Cable & Wireless installed new 155 Mbps links, for example between London and Manchester, to cope temporarily with the increased demand for bandwidth. SuperJANET IV followed these developments.154 The Higher Education Funding Council for England (HEFCE) agreed to fund a phased upgrade to the network, from 2.5 Gbps in 2001 to higher speeds by 2005. This upgrade would cost £40m. The JISC awarded the contract to WorldCom during 2000, with the condition that the company hand over the network for service by the end of year. WorldCom began to lay new fibre-optics, and the network became operational by January 2001.
151
SuperJANET III - Leading the Network to the Millennium and Beyond, UKERNA, 1997, Available from: http://www.ja.net/documents/UKERNA_News/1998/march/UKERNA_News4.html, Accessed on: 11 May 2004.
152
SuperJANET Phase III, UKERNA, 1997, Available from:
http://www.ja.net/documents/UKERNA_Bulletin/1997/october/Bullet2.html, Accessed on: 17 August 2004.
153
Plan for Phasing out the Use of SMDS, UKERNA, 1999, Available from:
http://www.ja.net/documents/UKERNA_News/1999/january/UKERNA_News6.html, Accessed on: 11 May 2004.
154
SuperJANET III Upgrade Plans, UKERNA, 1999, Available from:
http://www.ja.net/documents/UKERNA_News/1999/november/UKERNA_News9.html, Accessed on: 11 May 2004.
Key 1. Exeter 2. Cardiff 3. Bristol
4. Bristol C&W premises 5. RAL
6. ULCC
7. London C&W premises 8. Cambridge
9. Birmingham 10. Nottingham
11. Manchester C&W premises 12. Belfast
13. Manchester 14. Leeds
15. Leeds C&W premises 16. Newcastle
17. Edinburgh
Interior Backbone Node operated by Cable & Wireless
Backbone Edge Node operated by UKERNA and institutions 155 Mbps SDH backbone
operated by Cable & Wireless 155 Mbps SDH circuit operated by UKERNA 34 Mbps SDH circuit operated UKERNA 8 2 5 7 8 9 10 11 12 15 16 17 4 3 14 13 1
Figure 3.11. SuperJANET III in 1997.155
The new 2.5 Gbps circuits interconnected eight Core Points of Presence (CPoPs) which linked the MANs, by then known as regional networks, to SuperJANET (see Figure 3.12).156
155
For clarity, the figure only shows the backbone and access links.
156
10 Gbps DWDM backbone link 2.5 Gbps DWDM test-bed network
155 Mbps SDH link 2.5 Gbps dark fibre link 2.5 Gbps SDH link 622 Mbps SDH link 10 15 8 2 6 8 11 12 16 20 18 21 24 3 19 1 5 13 9 17 26 27 28 25 7 4 23 22 14 Key 1. SWERN
2. South Wales MAN 3. Bristol
4. Portsmouth 5. LeNSE
6. Thames Valley Network (TVN) 7. Reading 8. London 9. LMN 10. Kentish MAN 11. EastNet 12. MidMAN 13. North Wales MAN 14. EMMAN 15. NNW 16. Warrington 17. C&NL MAN 18. Leeds 19. YHMAN 20. Belfast 21. NorMAN 22. Clydenet 23. EaStMAN 24. Edinburgh 25. Glasgow 26. FaTMAN 27. AbMAN 28. UHI Network Figure 3.12. SuperJANET IV in 2003.
As usual, traffic continued to increase and in order to ensure that the backbone did not become overloaded, UKERNA began to plan more upgrades to the network. The first
Core Point of Presence Backbone Access Router
stage was to upgrade the backbone of the network from 2.5 to 10 Gbps.157 By the end of 2002, SuperJANET was running at 10 Gbps.158
The need to upgrade network capacity also occurred on other networks during this period. Examples include the Gigabit European Academic Network (GÉANT) and the Internet.159 GÉANT is a pan-European network which interconnects 28 national research and education networks, such as SuperJANET, and over 3,500 institutions (see Figure 3.13). Academics in many different fields use the network for different purposes. For example, GÉANT assists radio astronomers with the real-time transmission of data from many telescopes which are linked together to form a high- resolution instrument that captures data about phenomena in the universe, such as stars and galaxies.160 Another research network to upgrade its links is Abilene in the US. Abilene is the first stage of the Internet2 initiative. This initiative is organised by a consortium of universities, companies, and the US government. These organisations are working together to develop the technology and applications which will be necessary for the continued development of the Internet.
157
The SuperJANET Backbone: The Next Stride Forward, UKERNA, 2002, Available from:
http://www.ja.net/documents/UKERNA_News/2002/june/UKERNA_News19.html, Accessed on: 11 May 2004.
158
JANET.
159
In 2001, GÉANT replaced it predecessor, the Trans-European Network (TEN), which originally operated at 155 Mbps (TEN-155). Three years before, TEN-155 had replaced the TEN-34 network, in response to the need for increased bandwidth to support the traffic generated by the European National Research and Education Networks (NRENs). TEN-34 was the successor to EuropaNET, and replaced this network during 1997. See D. Robertson, GÉANT - Past, Present and Future, UKERNA, 2003, Available from: http://www.ja.net/documents/UKERNA_News/2003/December/NEWS25.pdf, Accessed on: 30 July 2004.
160
Astronomers and astrophysicists refer to this as Very Long Baseline Interferometry (VLBI).
Astronomers usually record the data from VLBI onto removable media such as magnetic tapes and then transport the media to a central location where processing takes place. With GÉANT, radio
astronomers, who are part of the Joint Institute for VLBI in Europe (JIVE), are experimenting with real-time VLBI, which means that the network transmits the data from the telescopes. On 22 September 2004, astronomers successfully demonstrated the viability of electronic-VLBI (e-VLBI). Telescopes throughout Europe and the Arecibo radio telescope in Puerto Rico observed a supergiant star,
IRC+10420, which is approximately 15,000 light years from the Earth. The combined resolution of the telescopes was about 5 times greater than the Hubble Space Telescope. The astronomers transmitted the 9 Terabits of data from the telescopes at 32 Mbps through GÉANT to JIVE. A supercomputer then combined the data and returned the information to the astronomers who produced images of the star. As the press release for the e-VLBI event states, “In a sense, the Internet itself acts like a telescope, performing the same task as the curved surfaces of the individual radio dishes.” See A. Abbott, “Report Praises European Radio Telescope Network,” Nature, 28 September 2000, p. 437, GEANT, DANTE Ltd, 2003, Available from: http://archive.dante.net/geant/Geant.mov, Accessed on: 18 August 2004, and Astronomers Demonstrate a Global Internet Telescope, Arecibo Observatory, 2004, Available from: http://www.naic.edu/~astro/aovlbi/press_release/eVLBI_AR.pdf, Accessed on: 17 December 2004.
To Abilene
To Turkey
To Cyprus To Malta
To Russia
To Estonia and Latvia
To Lithuania To Israel 10 Gbps link 2.5 Gbps link 34-155 Mbps link 622 Mbps link Figure 3.13. GÉANT in 2004.161
When Abilene became operational during 1999 it had a backbone with a bandwidth of 2.5 Gbps. During 2003, work began on upgrading the core of the network to 10 Gbps. When complete, this upgrade will help to support the traffic generated by 220
161
Lighting the Way to the European Research Area, DANTE, 2004, Available from:
Internet2 organisations.162 In addition to upgrading the bandwidth of the network, Abilene is also piloting a new version of the Internet Protocol known as IP version 6 (IPv6). IPv6 will address several issues, the most serious of which is the limited number of addresses provided by its predecessor, IP version 4 (IPv4). Other networks, such as GÉANT and SuperJANET, are also exploring this standard. For instance, during September 2003, UKERNA deployed IPv6 on the SuperJANET backbone, enabling institutions to experiment with this new protocol.
The second stage of UKERNA’s upgrade plan is SuperJANET phase V. With WorldCom’s contract due to expire by the end of 2005, work began on the requirements analysis for this new network during September 2003. SuperJANET V will address several areas.163 Ensuring the reliable end-to-end delivery of information on a network has become increasingly important. Accessing remote databases, sending and receiving e-mails, browsing the Web, and using new services such as videoconferencing, all require the reliable delivery of information. Aware of this fact, UKERNA believed that it would need technical standards to ensure a satisfactory service for users. To help support applications such as these, UKERNA is looking at technologies such as IP Quality of Service (IP QoS) and IPv6. These will support applications such as videoconferencing, and help to ensure that the performance of the network remains manageable and consistent. SuperJANET V will also need to address the issue of network capacity. Since the funding bodies announced JANET during 1984, the JNT and UKERNA had continually increased the bandwidth available to users (see Table 3.1). Initially this meant incrementally upgrading the network’s bandwidth, for example, from 2 to 8 Mbps. The 8 Mbps upgrade was the largest upgrade to JANET, since the funding bodies had established the network.
162
See About Abilene, Internet2, 2003, Available from: http://abilene.internet2.edu/about/, Accessed on: 18 August 2004, About Internet2, Internet2, 2004, Available from:
http://www.internet2.edu/about/aboutinternet2.html, Accessed on: 18 August 2004, and D. Fowler, “The Next Internet,” NetWorker, September 1999, pp. 20-29.
163
Requirements Analysis: An Opportunity to Shape the Future of JANET, UKERNA, 2003, Available from: http://www.ja.net/SJ5/requirements_analysis.pdf, Accessed on: 30 July 2004.
Table 3.1. Evolution of bandwidth on JANET and SuperJANET.164
Year Network Bandwidth of backbone
1984 to early 1990s JANET 9.6 Kbps followed by 2 then 8 Mbps
1993 SuperJANET I 34 Mbps
1995 SuperJANET II 34 and 155 Mbps
1998 SuperJANET III 155 Mbps
2001 SuperJANET IV 2.5 and 10 Gbps
2005 SuperJANET V Greater than 10 Gbps
However, with the introduction of SuperJANET, this upgrade became insignificant. SuperJANET originally operated at 34 Mbps, but eight years later the backbone transmitted information at 10 Gbps. By 2002, the bandwidth on the network was one million times greater than the original capacity of JANET.165 The increase in TCP/IP traffic on both JANET and SuperJANET provided the catalyst for these changes. Traffic on the network doubles every nine months, and projections suggest that the exponential rise in traffic will continue, with over 60 percent more traffic by 2013 compared to 2002.166 To support the increasing amount of traffic, the JISC can employ technologies, such as the fibre-optic Dense Wave Division Multiplexing (DWDM) system, which can transmit data at several rates including 40 Gbps (see Figure 3.14).167 Irrespective of the technology employed within SuperJANET V, it seems likely that traffic will continue to increase, based on the growth seen throughout JANET’s existence. Whatever happens, the continual upgrades to SuperJANET have achieved three outcomes. The upgrades expanded the bandwidth to support the increasing traffic generated by the community. For the past 13 years, this traffic has consisted of TCP/IP packets therefore reinforcing the demise of X.25. As Christopher Cooper, a member of the SuperJANET project team remembers, “what happened was as the SuperJANET era came in, so X.25 was swept away.”168 The development of SuperJANET also achieved another more important outcome: it helped to consolidate TCP/IP as the standard used on the UK’s national academic computer network.
164
Ibid.
165
M. Yardley, Next-Generation JANET Backbone Infrastructure: An Assessment of the Options Available, UKERNA, 2004, Available from: http://www.ja.net/SJ5/final-report.pdf, Accessed on: 10 May 2004.
166
During 2002, the SuperJANET 4 backbone transmitted 6.5 Petabytes (Pbs), 6.5 million Gbs, during the year. If the amount of traffic continues to increase, the network will be transmitting 10.5 Pbs per year by 2013. See Ibid. Additional information from S. Wood, E-mail to D. Rutter, 13 May 2004.
167
Yardley, Next-Generation JANET Backbone Infrastructure and Appendix F.
168
Main DWDM links Additional links Key 1. Bristol 2. Reading 3. London 4. The Docklands 5. Cambridge 6. Birmingham 7. Nottingham 8. Manchester 9. Leeds 10. Newcastle 11. Glasgow 12. Edinburgh 8 10 12 1 3 2 4 5 6 7 8 9 11
Figure 3.14. A possible topology for SuperJANET V.169
169
SuperJANET V can use several fibre-optic solutions, including DWDM. See Appendix F. Core node
Repeater