[jeffwheeler]

Their website links [1] to a presentation at Stanford [2]. Mendel Rosenblum briefly compares their concept with PTP at about 45:54. He says:

> Those people [fintech, etc.] are interested in our stuff, so obviously [that] means that thing [PTP] is not perfect for them. Part of the problem is, you’re trying to measure individual packets that are going through and get times. It means you have some clock there that you’re reading, and when it goes into the switch, and when it comes out, like, what is that clock doing in terms of its varying in frequency, and stuff like that. And then you get one sample and try to make things of it. It sorta pales in comparison to this big data approach we’re looking about.

This seems like a mischaracterization of PTP (802.1AS), which does use multiple samples to syntonize.

[1] https://www.clockwork.io/resource/ [2] https://www.youtube.com/watch?v=Opf9CBwP5R8

[assttoasstmgr]

Not just that, but PTP switches modify the frame header to take into account the delta of the propagation delay through the switch. Everything is synced to the GM clock which is typically sync'd to GPS and your GM clock can itself be designed to ensure stability (e.g. temperature controlled oscillator). Furthermore, if reading the incoming data using a specialized NIC (they do this in finance, high speed trading for example) the timestamps are decoded in hardware. All this is done at the layer 2 level.