Wireshark-users: Re: [Wireshark-users] Jitter wrong in wireshark?
From: "Anders Broman" <a.broman@xxxxxxxxx>
Date: Sat, 24 Feb 2007 08:49:34 +0100
Hi, If I understood the previous discussion correctly the RTP timestamp which is based on the sampling frequency is used in the calculations. If the wrong sampling frequency is used the calculations will be off. If a dynamic PT is used (>95) it probably not G711. Best regards Anders ________________________________________ Från: wireshark-users-bounces@xxxxxxxxxxxxx [mailto:wireshark-users-bounces@xxxxxxxxxxxxx] För Juan.Wortley@xxxxxxxxx Skickat: den 23 februari 2007 18:29 Till: wireshark-users@xxxxxxxxxxxxx Ämne: Re: [Wireshark-users] Jitter wrong in wireshark? Hi Anders, good question. I´m not sure but I guess is codec is PCMA G711 8KHz (will take a look during call setup in a couple of hours). However "Payload type" is 97 (0x61), and wireshark shows it as "Payload type=Unknown" According to the formula, jitter calculation depends on timestamps and arrival time differences. I don´t know how codec could affect. BR Juan ________________________________________ From: wireshark-users-bounces@xxxxxxxxxxxxx [mailto:wireshark-users-bounces@xxxxxxxxxxxxx] On Behalf Of ext Anders Broman (AL/EAB) Sent: Viernes, 23 de Febrero de 2007 01:05 p.m. To: Community support list for Wireshark Subject: SV: [Wireshark-users] Jitter wrong in wireshark? Hi, Which codec is used? Best regards Anders ________________________________________ Från: wireshark-users-bounces@xxxxxxxxxxxxx genom Juan.Wortley@xxxxxxxxx Skickat: fr 2007-02-23 16:53 Till: wireshark-users@xxxxxxxxxxxxx Ämne: [Wireshark-users] Jitter wrong in wireshark? Hi All, Below is a rtp analysis from a wireshark 0.99.5 capture in a live network. Doing by hand jitter calculation it doesn´t match. And of course, if below data is real it means we are having jitter of more than 1 minute !! Exampe: first jitter should be 138.90/16 = 8.68125 [ms] and is showing 8803,82 [ms] !!! Do someone know what could be wrong or what I´m missing? BR Juan Forward Packet Sequence Delta (ms) Jitter (ms) IP BW (kbps) Marker Status Date Length 1 0 0.00 0.00 1.45 [ Ok ] 02/19/2007 18:44:25.915 231 2 1 138.90 8803.82 2.90 [ Ok ] 02/19/2007 18:44:26.053 231 3 2 119.59 17058.61 4.34 [ Ok ] 02/19/2007 18:44:26.173 231 4 3 139.67 24796.21 5.79 [ Ok ] 02/19/2007 18:44:26.313 231 5 4 180.22 32047.69 7.24 [ Ok ] 02/19/2007 18:44:26.493 231 6 5 241.67 38842.10 8.69 [ Ok ] 02/19/2007 18:44:26.735 231 7 6 96.71 45220.93 10.14 [ Ok ] 02/19/2007 18:44:26.831 231 8 7 198.41 51194.72 10.14 [ Ok ] 02/19/2007 18:44:27.030 231 9 8 205.78 56794.69 8.69 [ Ok ] 02/19/2007 18:44:27.235 231 10 9 193.62 62045.42 8.69 [ Ok ] 02/19/2007 18:44:27.429 231 11 10 197.77 66967.72 8.69 [ Ok ] 02/19/2007 18:44:27.627 231 12 11 208.31 71581.72 7.24 [ Ok ] 02/19/2007 18:44:27.835 231 13 12 190.92 75908.43 8.69 [ Ok ] 02/19/2007 18:44:28.026 231 14 13 199.23 79964.20 8.69 [ Ok ] 02/19/2007 18:44:28.225 231 15 14 183.31 83767.48 8.69 [ Ok ] 02/19/2007 18:44:28.409 231 16 15 200.50 87331.98 8.69 [ Ok ] 02/19/2007 18:44:28.609 231 17 16 216.07 90672.73 8.69 [ Ok ] 02/19/2007 18:44:28.825 231 18 17 137.81 93809.57 8.69 [ Ok ] 02/19/2007 18:44:28.963 231 19 18 139.08 96750.28 8.69 [ Ok ] 02/19/2007 18:44:29.102 231 20 19 119.60 99508.41 10.14 [ Ok ] 02/19/2007 18:44:29.222 231 21 20 119.59 102094.16 10.14 [ Ok ] 02/19/2007 18:44:29.341 231 22 21 119.18 104518.33 10.14 [ Ok ] 02/19/2007 18:44:29.460 231 23 22 126.80 106790.51 11.58 [ Ok ] 02/19/2007 18:44:29.587 231 24 23 112.05 108921.60 11.58 [ Ok ] 02/19/2007 18:44:29.699 231 25 24 145.14 110917.43 11.58 [ Ok ] 02/19/2007 18:44:29.844 231 26 25 115.57 112790.36 13.03 [ Ok ] 02/19/2007 18:44:29.960 231 27 26 118.57 114546.05 13.03 [ Ok ] 02/19/2007 18:44:30.079 231 28 27 139.44 116190.71 13.03 [ Ok ] 02/19/2007 18:44:30.218 231 29 28 120.40 117733.77 13.03 [ Ok ] 02/19/2007 18:44:30.338 231 30 29 118.59 119180.49 13.03 [ Ok ] 02/19/2007 18:44:30.457 231 31 30 120.00 120536.71 13.03 [ Ok ] 02/19/2007 18:44:30.577 231 32 31 120.23 121808.15 13.03 [ Ok ] 02/19/2007 18:44:30.697 231 33 32 119.60 123000.17 13.03 [ Ok ] 02/19/2007 18:44:30.817 231 34 33 118.72 124117.74 13.03 [ Ok ] 02/19/2007 18:44:30.936 231 35 34 119.88 125165.39 13.03 [ Ok ] 02/19/2007 18:44:31.055 231 36 35 146.42 126145.90 13.03 [ Ok ] 02/19/2007 18:44:31.202 231 37 36 57.34 118265.37 11.90 SET Incorrect timestamp 02/19/2007 18:44:31.259 90 Reverse Packet Sequence Delta (ms) Jitter (ms) IP BW (kbps) Marker Status Date Length 44 1 0.00 0.00 1.45 [ Ok ] 02/19/2007 18:44:36.119 231 46 2 126.78 99992.08 2.90 [ Ok ] 02/19/2007 18:44:36.246 231 47 3 293.16 193724.25 4.34 [ Ok ] 02/19/2007 18:44:36.539 231 48 4 159.97 281606.49 5.79 [ Ok ] 02/19/2007 18:44:36.699 231 49 5 119.98 363998.58 7.24 [ Ok ] 02/19/2007 18:44:36.819 231 50 6 160.07 441238.67 8.69 [ Ok ] 02/19/2007 18:44:36.979 231 51 7 261.00 513644.94 8.69 [ Ok ] 02/19/2007 18:44:37.240 231 52 8 43.09 481544.82 7.56 SET Incorrect timestamp 02/19/2007 18:44:37.283 90
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