2002 - cesnet

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int size=2097152;setsockopt(sock, SOL_SOCKET, SO_RCVBUF, (char *)&size, sizeof(int));setsockopt(sock, SOL_SOCKET, SO_SNDBUF, (char *)&size, sizeof(int));The advantage of a manual setup for all TCP connections on the operating systemlevel is that it works with every application, without any need to modify it.On the other hand, wasting memory is a disadvantage, as only some TCP connectionsactually need large buffer memory. An example is again given for theLinux OS, the values indicate the minimum, standard, and maximum size of thebuffer, which the operating system allocates to individual connection accordingto heuristics, based on the actual memory consumption and other configurationparameters (an example for an initial setup of 2 MB):sysctl -w net/ipv4/tcp_rmem=”4096 2097152 8388608”sysctl -w net/ipv4/tcp_wmem=”4096 2097152 8388608”It is obvious that this solution is almost unacceptable for a server with hundredsof active TCP connections. For more or less automatic configuration for individualTCP connections, there are several alternative extensions of the operatingsystem kernel, in the form of patches or auxiliary daemons, developed as partof special projects. These mechanisms are now being further developed.Unfortunately, increasing the buffer memory and the sender window is notenough to ensure reliable and high throughputs in large high-speed networks.It is necessary to adjust the algorithm of congestion control at the sender, andanalyse and solve a number of phenomena encountered during high-speedtransmissions.We are now intensively working on these issues. Some of the phenomena canbe analysed by analysing the packet flows, recorded by the tcpdump program.Data are analysed by the tcptrace program after the connection is terminated.Another possibility is a real-time analysis of state variables maintained by theweb100 kernel extension.We created several scripts for the correlation of information acquired fromthese two sources. For instance, the diagram in Figure 9.13 shows the developmentof rwnd (upper part of the diagram), acquired from the data flow tracedby tcpdump and the development of cwnd (lower part of the diagram), acquiredthrough the programming interface to the web100 extension. The figure showsrwnd window moderated by the TCP receiver in Linux in order to prevent networkcongestion with sudden data bursts from the sending application. Thesender carries out similar moderation with its cwnd calculated window.It is also useful to estimate the available bandwidth of the route. The tools forthese purposes are the subject of active research. As an example, there are thepathload and ABwE programs. Further outcome will be presented during thePFLDnet 2003 conference at the beginning of the next year.132 High-speed National Research Network and its New Applications <strong>2002</strong>
Figure 9.13: Example of a course of cwnd and rwnd9.6 Other Activities in ProgressWe have participated in preparation of the European PRT (Performance ResponseTeam) activity, proposing the elaboration of an “End-to-End PerformanceCookbook”, on which we are now working. In December, there will bea meeting concerning further proceedings in the PRT activity in 2003. Amongthe participants, there is expected to be Dante and the NRENs of five countries(Czech Republic, Ireland, United Kingdom, Switzerland, Italy).High-speed National Research Network and its New Applications <strong>2002</strong>133
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2002High-speed NationalResearch Net
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Table of Contents1 Introduction 92
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6.4.3 Support of Special Events. .
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14.3 Cisco ICM Software . . . . . .
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1 IntroductionThe report presented
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2 Brief SummaryThe research plan ti
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men. We designed the basic concept
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2.4 Other ProjectsThe objective of
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3 Operation of CESNET2During 2002,
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Canarie622 MbpsESNET622 MbpsGÉANT/
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central network core routers with t
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The existing logical topology of mu
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The logical core topology anticipat
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Within the informative part, we req
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3.6 Statistical Traffic Analysis3.6
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Figure 3.8: Influence of time step
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Praha-Plzeň, 2.5 GbpsPraha-Ústí
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CESNET2-GÉANT, 1.2 Gbps (october)C
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Part IStrategic Projects
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4 Optical Networks and theirDevelop
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US (TeraGrid with backbone 4 × 10
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ApplicationMiddlewareHigh bandwidth
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4.2.2 User InterfaceSubscribers (me
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ers will move and that other types
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GermanyCheb10 G34 MPlzeňGÉANT 622
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It is also possible to implement th
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Chemical Technology and PASNET, we
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Manufacturerwww.accton.comwww.actio
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particularly based on the fact that
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0101 NRZlaserMach-ZendermodulatorED
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Cisco ONS 15201boosterfiber 130 kmC
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5 IP version 6Further expansion of
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5.2.1 IPv6 Network TopologyFor the
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Missing in this list are especially
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5.2.7 Connecting End Site NetworksI
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5.4 IPv6 User Services and Applicat
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sible reprogramming of functions, a
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IPBIpb_0HFEHfe_1SORSor_0LUPLup_0RQR
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As regards our router on the PC pla
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the activities of our project. In 2
Page 81 and 82: 6 Multimedia Transmissions6.1 Objec
Page 83 and 84: scaling is considerably restricted;
Page 85 and 86: Figure 6.1: Modified program for sh
Page 87 and 88: 6.3.5 Direct Support for Pilot Grou
Page 89 and 90: programs which control the integrat
Page 91 and 92: Figure 6.4: Example of broadcast fr
Page 93 and 94: Figure 6.5: Set of tuners and serve
Page 95 and 96: and transfer the solution to an ope
Page 97 and 98: The actual computing capacity of Me
Page 99 and 100: 7.1.2 Information ServicesMetaCentr
Page 101 and 102: Figure 7.1: Grid nodes for SC2002an
Page 103 and 104: (December 2002). This was one of th
Page 105 and 106: the use of 158 processors). When we
Page 107 and 108: 8 Voice Services in CESNET2The proj
Page 109 and 110: Figure 8.1: Number of phone calls i
Page 111 and 112: VoGWs of members involved in the pr
Page 113 and 114: connection and compare the features
Page 115 and 116: • Extensive possibilities for the
Page 117 and 118: H.323 WorldSIP PhoneMS Messengerand
Page 119 and 120: ation with students at the Strahov
Page 121 and 122: 9 Quality of Service in HighspeedNe
Page 123 and 124: In addition, Juniper routers make u
Page 125 and 126: We tried to divide the capacity of
Page 127 and 128: low with respect to the capacity of
Page 129 and 130: Figure 9.10: Loss rate on Prague-Po
Page 131: sendingapplicationTCP senderseqackp
Page 135 and 136: Part IIInternational Projects
Page 137 and 138: 10 GÉANTSince 1996, CESNET has bee
Page 139 and 140: Figure 10.2: Utilization of individ
Page 141 and 142: 11 DataGridSince 2001, our research
Page 143 and 144: Therefore, we organized a meeting w
Page 145 and 146: 12 SCAMPISCAMPI (Scaleable Monitori
Page 147 and 148: 12.3.1 WP0 - Requirement AnalysisTh
Page 149 and 150: 1 6 12 18 24 30requirements analysi
Page 151 and 152: Part IIIOther Projects
Page 153 and 154: 13 Online Education Infrastructurea
Page 155 and 156: 13.1.2 Construction of a Teleinform
Page 157 and 158: with high-capacity disk memories co
Page 159 and 160: If the collaboration of individual
Page 161 and 162: ten, whereas items in the hyperlink
Page 163 and 164: Besides that, we processed some lec
Page 165 and 166: CallManager was designed using open
Page 167 and 168: tre, when we were forced to handle
Page 169 and 170: 15 Intelligent NetFlow AnalyserThe
Page 171 and 172: In the second half-year, we complet
Page 173 and 174: 15.4 ConclusionDuring 2002, our tea
Page 175 and 176: • data space consolidation (easy
Page 177 and 178: ecord size [kB] 256 512 1024 2048 4
Page 179 and 180: Figure 16.3: Nishan-Linux measureme
Page 181 and 182: 16.3.1 No SecurityThe initiator is
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vices. These features mainly involv
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Figure 17.1: www.cesnet.cz• We ha
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The meeting was broadcast live via
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Most of the problems connected with
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Standard manipulator (privileged us
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19 Security of Local CESNET2Network
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Moreover, the program was complemen
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in the network of AV ČR Praha-Krč
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19.5 Future Plans, Expected Further
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InternetNTPEthernetKPCPPSLabelPPSLa
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generated by the NTP server. Its ou
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21 Platforms for Streaming andVideo
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streaming serverAAA (LDAPS) server1
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21.5 Video Content CollaborationPla
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First of all, we had to define an a
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international-scale broadcast will
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Part IVConclusion and Annexes
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23 ConclusionThe current developmen
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AList of connected institutionsA.1
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institutionconnection [Mbps]Institu
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Karásek Miroslav, Ing., DrSc. Czec
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Voral Pavel, Ing.Voříšek Martin,
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Burčík J.: Optické přepínání
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Veselá S.: Aktivity sdružení CES
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Krsek M.: Platformy pro streaming m
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Zatloukal K., Křivánek V.: Videok
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Satrapa P.: Scavenger: Za Internet
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