Echo Delay Measurements With GGP Packets IEN 163 R.G.Jones November 1980 University College London GGP IEN Echo 163 Delays 1. Introduction This IEN is intended to facilitate discussion of internet delays as seen from the UK. It presents a series of measurements of round trip times for GGP echo packets. The GGP packet generator was an LSI-11 host on the UCL Port Expander (the UCLnet/SATNET/Nullnet gateway is another host on this Port Expander). Round-trip times were measured by timestamping the packet on initiation of output and again on completion of input. The time reference was a programmable clock with 1 millisecond resolution (based on a 10 MHz crystal). Echo delays were measured for the following destinations: address UCLnet/SATNET/Nullnet gateway 11 3 0 42 RSRE PPSN/Nullnet gateway 35 6 0 0 Goonhilly SIMP 4 0 0 63 BBN SATNET/ARPANET gateway 4 0 0 61 Bragg PR/ARPANET gateway 10 0 0 38 SRI PR1/ARPANET gateway 10 3 0 51 SRI PR2/ARPANET gateway 10 1 0 51 For each destination, 1000 packets were sent at 4 second intervals. The results are presented in the following pages. Each page is devoted to one destination. Two histograms are provided for the given destination, the upper showing the structure of the distribution of times and the lower with a scale common to all destinations to simplify comparisons. On each histogram the count is given as a percentage of the total number of replies received. The heading gives the total number of replies received for the 1000 packets sent; the minimum, maximum and average times for all the replies; and the number of replies falling within, above and below the histogram range plotted. The round trip times given are in milliseconds. The date of the experiment is in the English (day/month) format and the time is given as GMT. - 1 - R.G.Jones ECHO DESTINATION UCL UCL/SAT gway DATE 17/11/80 TIME 14.00-15.07 1000 packets minimum time 30 maximum 40 average 32 999 within histogram range 0 below 1 above count | | 84%_| _____ | |/////| | |/////| | |/////| | |/////| | |/////| | |/////| | |/////| | |/////| | |/////| | |/////| | |/////| | |/////| | |/////| | |/////| | |/////|_____ | |/////|/////| | |/////|/////| |_____ _____|/////|/////|_____ _____ _____ _____ _____ _____ 0_|________________________________________________________________ time | | | | | | | | | | | ms 30 31 32 33 34 35 36 37 38 39 40 ECHO DESTINATION UCL UCL/SAT gway DATE 17/11/80 TIME 14.00-15.07 1000 packets minimum time 30 maximum 40 average 32 1000 within histogram range 0 below 0 above count | | 100%_|_ |/| |/| |/| |/| |/| |/| |/| |/| |/| |/| |/| |/| |/| |/| |/| |/| |/| |/|_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 0_|________________________________________________________________ time | | | | | | | | | | | ms 0 300 600 900 1200 1500 1800 2100 2400 2700 3000 - 2 - ECHO DESTINATION RSRE PPSN/N gway DATE 14/11/80 TIME 12.15-13.22 1000 packets minimum time 244 maximum 346 average 263 983 within histogram range 5 below 12 above count | | 44%_| _ | |/| | |/| | |/| | |/| | |/| | |/| | _|/| | |/|/| | |/|/| | |/|/| | |/|/|_ | |/|/|/| | |/|/|/| | |/|/|/| | |/|/|/| | |/|/|/| | _|/|/|/|_ |_ _ _ _ _ _ _ _ _ _ _|/|/|/|/|/|_ _ _ _ _ _ _ _ _ _ _ _ _ _ 0_|________________________________________________________________ time | | | | | | | | | | | | | | | | ms 250 252 254 256 258 260 262 264 266 268 270 272 274 276 278 280 ECHO DESTINATION RSRE PPSN/N gway DATE 14/11/80 TIME 12.15-13.22 1000 packets minimum time 244 maximum 346 average 263 1000 within histogram range 0 below 0 above count | | 99%_| _ | |/| | |/| | |/| | |/| | |/| | |/| | |/| | |/| | |/| | |/| | |/| | |/| | |/| | |/| | |/| | |/| | |/| |_ _|/|_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 0_|________________________________________________________________ time | | | | | | | | | | | ms 0 300 600 900 1200 1500 1800 2100 2400 2700 3000 - 3 - ECHO DESTINATION Goonhilly SIMP DATE 17/11/80 TIME 10.05-11.12 997 packets minimum time 80 maximum 284 average 104 954 within histogram range 0 below 43 above count | | 14%_| _ | |/| | |/|_ | |/|/| | |/|/| | _|/|/| | |/|/|/|_ | |/|/|/|/| | |/|/|/|/| | |/|/|/|/| | |/|/|/|/| | |/|/|/|/| | |/|/|/|/| | |/|/|/|/|_ _ | |/|/|/|/|/| |/|_ _ _ _ | _ _ _ _|/|/|/|/|/|_ _ _ |/|/|/| |/|/| | |/|/|/|/|/|/|/|/|/|/|/|/|_ _|/|/|/|_ _|/|/| |_|/|/|/|/|/|/|/|/|/|/|/|/|/|_|/|/|/|/|/|/|/|/|_ _ _ _ _ _ |/|/|/|/|/|/|/|/|/|/|/|/|/|/|/|/|/|/|/|/|/|/|/|/|/|/|/|/|/|_ 0_|________________________________________________________________ time | | | | | | | | | | | | | | | | ms 80 84 88 92 96 100 104 108 112 116 120 124 128 132 136 140 ECHO DESTINATION Goonhilly SIMP DATE 17/11/80 TIME 10.05-11.12 997 packets minimum time 80 maximum 284 average 104 997 within histogram range 0 below 0 above count | | 61%_|_ |/| |/| |/| |/| |/| |/| |/|_ |/|/| |/|/| |/|/| |/|/| |/|/| |/|/| |/|/| |/|/| |/|/| |/|/| |/|/|_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 0_|________________________________________________________________ time | | | | | | | | | | | ms 0 300 600 900 1200 1500 1800 2100 2400 2700 3000 - 4 - ECHO DESTINATION BBN SATNET/A gway DATE 17/11/80 TIME 8.40-9.47 994 packets minimum time 1443 maximum 4344 average 1929 983 within histogram range 0 below 11 above count | | 15%_| _ | |/| | _|/| _ | |/|/|_|/| | _|/|/|/|/| | |/|/|/|/|/| | |/|/|/|/|/|_ | |/|/|/|/|/|/| | |/|/|/|/|/|/| | _|/|/|/|/|/|/| | |/|/|/|/|/|/|/| | |/|/|/|/|/|/|/| | |/|/|/|/|/|/|/| | |/|/|/|/|/|/|/|_ | |/|/|/|/|/|/|/|/| | _|/|/|/|/|/|/|/|/| | |/|/|/|/|/|/|/|/|/| | _ _ _|/|/|/|/|/|/|/|/|/|_ _ _ _ _ _ _ |_ _|/|/|/|/|/|/|/|/|/|/|/|/|/|/|/|_ _|/|/|_|/|_ _|/|_ _ _ _ 0_|________________________________________________________________ time | | | | | | | | | | | ms 1400 1550 1700 1850 2000 2150 2300 2450 2600 2750 2900 ECHO DESTINATION BBN SATNET/A gway DATE 17/11/80 TIME 8.40-9.47 994 packets minimum time 1443 maximum 4344 average 1929 985 within histogram range 0 below 9 above count | | 28%_| _ | |/|_ | |/|/| | |/|/| | |/|/| | |/|/| | _|/|/| | |/|/|/| | |/|/|/|_ | |/|/|/|/| | |/|/|/|/| | |/|/|/|/| | |/|/|/|/| | |/|/|/|/| | |/|/|/|/| | |/|/|/|/| | _|/|/|/|/| | _|/|/|/|/|/|_ _ _ _ _ |_ _ _ _ _ _ _ _ _ _ _ _ _ _ _|/|/|/|/|/|/|/|/|_|/|/|/|_ _ _ 0_|________________________________________________________________ time | | | | | | | | | | | ms 0 300 600 900 1200 1500 1800 2100 2400 2700 3000 - 5 - ECHO DESTINATION Bragg PR/A gway DATE 12/11/80 TIME 9.45-10.52 1000 packets minimum time 1689 maximum 8402 average 2270 982 within histogram range 1 below 17 above count | | 13%_| _ _ | |/| _|/| | |/|_|/|/| | |/|/|/|/|_ | |/|/|/|/|/| | |/|/|/|/|/| | _|/|/|/|/|/| | |/|/|/|/|/|/|_ | |/|/|/|/|/|/|/| | |/|/|/|/|/|/|/| | |/|/|/|/|/|/|/| | |/|/|/|/|/|/|/| | _|/|/|/|/|/|/|/| | |/|/|/|/|/|/|/|/| | _|/|/|/|/|/|/|/|/| | _|/|/|/|/|/|/|/|/|/|_ | _|/|/|/|/|/|/|/|/|/|/|/| | _ _|/|/|/|/|/|/|/|/|/|/|/|/|_ _ _ _ _ _ _ _ _ _ _ _ |_|/|/|/|/|/|/|/|/|/|/|/|/|/|/|/|/|/|/|/|/|/|/|/|/|/|/|_ _ _ 0_|________________________________________________________________ time | | | | | | | | | | | ms 1700 1850 2000 2150 2300 2450 2600 2750 2900 3050 3200 ECHO DESTINATION Bragg PR/A gway DATE 12/11/80 TIME 9.45-10.52 1000 packets minimum time 1689 maximum 8402 average 2270 975 within histogram range 0 below 25 above count | | 25%_| _ _ | |/|/| | |/|/| | |/|/| | |/|/| | |/|/|_ | |/|/|/| | |/|/|/| | |/|/|/| | _|/|/|/| | |/|/|/|/| | |/|/|/|/| | |/|/|/|/| | |/|/|/|/| | _|/|/|/|/| | |/|/|/|/|/| | _|/|/|/|/|/|_ | _|/|/|/|/|/|/|/|_ _ _ _ _ |_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _|/|/|/|/|/|/|/|/|/|/|/|/|/| 0_|________________________________________________________________ time | | | | | | | | | | | ms 0 300 600 900 1200 1500 1800 2100 2400 2700 3000 - 6 - ECHO DESTINATION SRI PR1/A gway DATE 14/11/80 TIME 11.00-12.07 998 packets minimum time 1715 maximum 5574 average 2266 978 within histogram range 0 below 20 above count | | 13%_| _ | |/| | |/|_ _ | |/|/|/|_ | |/|/|/|/|_ | |/|/|/|/|/| | |/|/|/|/|/| | _|/|/|/|/|/|_ | |/|/|/|/|/|/|/| | |/|/|/|/|/|/|/| | |/|/|/|/|/|/|/| | |/|/|/|/|/|/|/| | _|/|/|/|/|/|/|/| | |/|/|/|/|/|/|/|/| | |/|/|/|/|/|/|/|/| | _ _ _|/|/|/|/|/|/|/|/| | _|/|/|/|/|/|/|/|/|/|/|/|_ _ _ | _|/|/|/|/|/|/|/|/|/|/|/|/|/|_ |/|_ _ _ _ _|/|_ _ |_|/|/|/|/|/|/|/|/|/|/|/|/|/|/|/|_|/|/|/|/|/|/|/|/|_|/|_ _ _ 0_|________________________________________________________________ time | | | | | | | | | | | ms 1700 1850 2000 2150 2300 2450 2600 2750 2900 3050 3200 ECHO DESTINATION SRI PR1/A gway DATE 14/11/80 TIME 11.00-12.07 998 packets minimum time 1715 maximum 5574 average 2266 970 within histogram range 0 below 28 above count | | 25%_| _ | |/| | |/|_ | |/|/| | |/|/| | |/|/|_ | |/|/|/| | |/|/|/| | |/|/|/| | _|/|/|/| | |/|/|/|/| | |/|/|/|/| | |/|/|/|/| | |/|/|/|/| | |/|/|/|/| | _ _|/|/|/|/| | |/|/|/|/|/|/|_ | _|/|/|/|/|/|/|/|_ _ _ _ _ |_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _|/|/|/|/|/|/|/|/|/|/|/|/|/| 0_|________________________________________________________________ time | | | | | | | | | | | ms 0 300 600 900 1200 1500 1800 2100 2400 2700 3000 - 7 - ECHO DESTINATION SRI PR2/A gway DATE 14/11/80 TIME 9.50-10.57 999 packets minimum time 1764 maximum 5438 average 2265 976 within histogram range 0 below 23 above count | | 14%_| _ | _ |/| | |/| |/| | |/|_ _|/|_ | |/|/|/|/|/| | |/|/|/|/|/| | |/|/|/|/|/| | |/|/|/|/|/| | _|/|/|/|/|/|_ | |/|/|/|/|/|/|/| | |/|/|/|/|/|/|/| | |/|/|/|/|/|/|/| | |/|/|/|/|/|/|/| | _|/|/|/|/|/|/|/| | |/|/|/|/|/|/|/|/| | _|/|/|/|/|/|/|/|/|_ | _ _ _|/|/|/|/|/|/|/|/|/|/| | _|/|/|/|/|/|/|/|/|/|/|/|/|/| _ _ _ _ _ _ |_|/|/|/|/|/|/|/|/|/|/|/|/|/|/|_ _|/|_ _ _|/|/|/|_|/|/|_ _ _ 0_|________________________________________________________________ time | | | | | | | | | | | ms 1700 1850 2000 2150 2300 2450 2600 2750 2900 3050 3200 ECHO DESTINATION SRI PR2/A gway DATE 14/11/80 TIME 9.50-10.57 999 packets minimum time 1764 maximum 5438 average 2265 964 within histogram range 0 below 35 above count | | 26%_| _ | _|/| | |/|/| | |/|/| | |/|/| | |/|/|_ | |/|/|/| | |/|/|/| | |/|/|/| | _|/|/|/| | |/|/|/|/| | |/|/|/|/| | |/|/|/|/| | |/|/|/|/| | |/|/|/|/| | _|/|/|/|/| | _|/|/|/|/|/|_ | _|/|/|/|/|/|/|/|_ _ |_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _|/|/|/|/|/|/|/|/|/|_ _|/|_ 0_|________________________________________________________________ time | | | | | | | | | | | ms 0 300 600 900 1200 1500 1800 2100 2400 2700 3000 - 8 -