Bunch of timeout/disconnections occur together

[toby]

This is related to my other question:
viewtopic.php?f=3&t=238

But I am posting a separate question specifically about what might
be the cause of the problem, which could lead to a solution.

On 3 or 4 occasions so far, everything is chugging along, seemingly fine,
messages flying back and forth among the clients, and then
suddenly, for a period of a minute or two, the server does not
receive any incoming messages - no heartbeats, no "real" messages, nothing.

As a result, it judges some, but not necessarily all, clients as "inactive",
and disconnects them. (I increased the timeout from 30 to 90 seconds,
hoping that if this occurs, to get "through" it ... we'll see.)

Throughout all this, there appear to be no other errors, or anything
else out of the ordinary.

After this brief interruption, clients reconnect, re-login, and everything
returns to normal.

We opened a ticket with our hosting company, and they just said,
"it's probably something in your app", and something about doing
"tcpdump" and "ping/traceroute". Which might be useful if we knew
when these events would occur, but we don't.

So I hope to at least get some useful ways to go about figuring out
what is going on here.

Anyone experience anything of this nature and have any advice?