Skip to main content
Accessibility Resource Center Skip to main content
Have a phone you love? Get up to $500 when you bring your phone. Plus, get iPhone 13, on us. Online only. With select 5G Unlimited plans. Ends 3.20. Buy now
end of navigation menu
Latency while in motion

I commute by train from NYC to the suburbs (northeast corridor), use EVDO card on the train. What I find is that as the train is moving, connection will be maintained, but latency will change, at more or less the same points on the route, from ~100 ms to 500-1000 ms, more or less instantly. Once the latency goes up, it jitters in the high range and never comes back down to 100 ms. Interestingly enough, if I kill the connection and re-establish it, the latency goes back to 100 ms and stays there (until I reach the next step-up point along the route). This is true both under Linux and Windows.


There are a couple of step-up points, all of which seem to be located in NJ and between Newark and the Hudson River. West of Newark, its smooth sailing for about half-hour.

I assume that increased latency has to do with hand-off between towers, but I am very puzzled as to why it would go up by so much. An extra IP hop should not be that costly. Perhaps during handoff, a modem is allocated the least possible amount of bandwidth?


Low latency is important to me, as I run interactive applications (over VNC or SSH), and keystroke latency at 100 ms is very usable, while at 500 ms its pretty much unusable.