[Asterisk-Users] Asterisk and network problems

[Wilson Pickett]

Slightly OT but if you know much about networks, please read and maybe you 
can suggest some things.

I have been running asterisk for about 1 year. Currently running 1.0.6 with 
2 X100P and 1 TDM400P with 3 FXS modules on a Pentium III-800 with 512M RAM. 
The system performs very well for both POTS and voIP. 

The box is connected to a fixed ip DSL line at 2048/256.
It registers with several SIP and IAX providers, three remote SIP phones, 
one remote IAXy.

There is often one provider or phone that will become unreachable for a 
moment, and I'm sure this happens on most DSL soho/home type connections. It 
isn't a problem and doesn't usually cause any symptoms except perhaps very 
occasional breaking up.

About 10 days ago, I started seeing message where ALL providers and phones 
would become "UNREACHABLE" for about 10 seconds, then the same packagae of 
messages saying they were now REACHABLE. This happens about every 20-60 
minutes, usually at least once every two hours or so. 

When this UNREACHABLE messages begins, ALL network data flow stops. If I am 
in ssh session, it looks like a disconnect, but about 10 secs later, I have 
the console again. 

Naturally, I contacted our ISP who finally saw some packet loss at the same 
time as I saw the "freeze". They contacted their upstream who didn't see any 
problems and now they are contacting the phone company. 

I have tried the following debug techniques:

1) watched traffic on another box connected to same router and see same 
problem (ping stops)
2) swapped out router - problem persisted
3) changed eth0 card 
4) swapped DSL phone filter and disconnected other extension
5) did a tcpdump and caught a freeze but see nothing unusual in the traffic

Needless to say, this condition makes voIP useless at a professional level. 
For personal use we need to tell people that if they suddenly hear silence 
for 10 seconds to "hold on and wait til the connection comes back", not 
really great.

While I'm waiting for the third service to check, if anyone has any 
suggestions or ideas to pursue, please send them either on or off list.

tia
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