2002 - cesnet

Figure 3.8: Influence of time step on line statistics – time step of 5 minutes(left) and 1 second (right)land, USA), within the High Performance Bandwidth Challenge. Concerning theprevious analysis of the measurement method, it is obvious that a sufficientlylong, massive and particularly continuous data flow will show up also duringthe operating measurement mode.The diagrams of high-capacity backbone lines report a steady increase in thevolume, with a visible drop during the period of summer holidays. Lines witha lower speed report a solid and stabilized rate of utilization. Except for thosewhich were upgraded during the year, there are no significant increases in theutilization. These lines directly connect smaller PoPs, therefore the traffic aggregationis considerably lower, but the oscillations higher.3.6.4 Utilization of External LinesDuring the year 2002, we managed to reach and maintain the situation in whichthe capacity of the lines in question was not limiting with respect to the naturallyincreasing traffic volume. Another development trend is the increase in theoutgoing traffic compared to the incoming one, current reaching the rate of 2:1.Line Input OutputCESNET2–GÉANT (October) 15.88 TB 19.22 TBCESNET2–Internet (November) 40.77 TB 94.24 TBCESNET2–NIX.CZ (November) 8.12 TB 10.11 TBTable 3.1: Summary of the external linesIn general, we may say that the networks of members of the CESNET associationand the CESNET2 backbone network offer an abundance of attractive sourcesof data which are subject to continuous interest among the community of usersand which have a critical share in the long-term development of line load.This particularly concerns the distribution archives of free operating systems(Linux, BSD) and other free software. The quality of these internal sources considerablycuts down the requirements of our users concerning data transmissionfrom external networks towards CESNET2.High-speed National Research Network and its New Applications 200231