Initial Discussion
For a Single Host : Estimating Drift
In each of the method, we get some 'p' packets from a server each of which contains the "timestamp" data. We calculate the "offset" from the each of the data packets we recieve using the formula suggested in RFC. Then we plot a point for each packet using these data as suggested in Method 1 and Method 2 below. We then apply the Linear Regression Model because time advances linearly. We use the slope of the Regression Line as the Estimated Drift in each of the method.
wait: 20; cushion: 0.400000; n_polls: 8; interval: 2.800000
interval.tv_sec: 2; interval.tv_usec: 799999; diff: 0.000001
Lookups handled
Back from event_base_dispatch
IPv4: 0x9c21bd8, 8 responses
- 149.20.68.28
- 1377716725.454970 offset +0.051814058, precision 0.000001907, SyncD 0.012725830, S 3
- 1377716728.258269 offset +0.051830451, precision 0.000001907, SyncD 0.012748718, S 3
- 1377716731.061638 offset +0.051796604, precision 0.000001907, SyncD 0.012771606, S 3
- 1377716733.864923 offset +0.051785300, precision 0.000001907, SyncD 0.012794495, S 3
- 1377716736.668215 offset +0.051801779, precision 0.000001907, SyncD 0.012817383, S 3
- 1377716739.471623 offset +0.051833478, precision 0.000001907, SyncD 0.012832642, S 3
- 1377716742.274970 offset +0.051812146, precision 0.000001907, SyncD 0.012855530, S 3
- 1377716745.078193 offset +0.051823378, precision 0.000001907, SyncD 0.012878418, S 3
Method 1 : Estimated Drift : 0.000001200
Method 2 : Estimated Drift : -0.002941176
IPv6: 0x9c23388, 8 responses
- (socktoa unknown family 34706)
- 1377716725.455035 offset +0.051861892, precision 0.000001907, SyncD 0.012725830, S 3
- 1377716728.258332 offset +0.051879908, precision 0.000001907, SyncD 0.012748718, S 3
- 1377716731.061638 offset +0.051866994, precision 0.000001907, SyncD 0.012771606, S 3
- 1377716733.864923 offset +0.051863642, precision 0.000001907, SyncD 0.012794495, S 3
- 1377716736.668215 offset +0.051875379, precision 0.000001907, SyncD 0.012817383, S 3
- 1377716739.471685 offset +0.051915173, precision 0.000001907, SyncD 0.012832642, S 3
- 1377716742.274970 offset +0.051891474, precision 0.000001907, SyncD 0.012855530, S 3
- 1377716745.078255 offset +0.051879093, precision 0.000001907, SyncD 0.012878418, S 3
Method 1 : Estimated Drift : 0.000003982
Method 2 : Estimated Drift : 0.002941176
-- RahulKatare - 2013-06-08