Verizon EVDO Issues

Thu Apr 9 14:31:10 UTC 2009

On Apr 9, 2009, at 7:15 AM, Robert E. Seastrom wrote:

>
> 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.

We observe this same kind of behavior with firewalls in the path  
watching for dead sessions they can clean up. Appears they send RSTs  
to both end points when they decide a session has gone away, as  
that'll let end hosts figure it out sooner. Same workaround of turning  
on keep=alives once a minute solves this too. The behavior in the case  
of firewalls makes sense, as state tables have to be cleaned up  
eventually.