Verizon EVDO Issues

Thu Apr 9 11:15:44 UTC 2009

Seth Mattinen <sethm at rollernet.us> writes:

> I have a few Sprint EVDO cards. They go into standby when nothing is
> actively going on and fire up within seconds when there is something to
> do. I regularly use everything from SSH to streaming video without any
> issues. I only notice the delay with SSH when I don't type anything for
> a few minutes and it has to come active again, but I can leave it idle
> for hours and it never drops.

Interesting.  When I got my Sprint EVDO card (u727) a year and a half
ago, they were pretty nasty about gunning down (bidirectional spoofed
RST coming out of the middle of the network somewhere) any TCP
sessions that were idle for ten minutes or more.  Quite repeatable and
verified on the downlow by People With Insight that this was in fact
expected behavior from boxes that were in the middle of the network
due to "politics" (unlike Verizon, Sprint appears to put no
restrictions on inbound connections to the evdo-host).  Putting this:

ServerAliveInterval 60

in ~/.ssh/config was an effective work-around.  I have not revisited
the issue to see if Sprint has corrected this behavior.  Perhaps
budget constraints or customer complaints have caused Sprint to
revisit the necessity of having extraneous hardware in their network.

-r