[ntp:questions] .1 Microsecond Synchronization

David Woolley david at ex.djwhome.demon.co.uk.invalid
Thu Jun 4 21:47:19 UTC 2009

John Hasler wrote:

> The first byte of the packet containing trade A arrives within 100ns of the
> first byte of the packet containing trade B (using custom software and
> hardware all the way down to the wire protocol, of course).

If they are interested in more than showing a lack of causal 
relationship, they will need to define a frame of reference (I guess UTC 
must do that), as the sign of the relative time between events in New 
York and London which are outside the light cone will depend on the 

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