[Asterisk-Users] Asterisk box with unreliable ping/latency

[Bjorn O]

Hello!

 

Over the last couple of days I’ve been trouble shooting a strange problem
with Asterisk.

 

First of all, I should say that I’ve been running Asterisk on a Fedora Core
3 box since last May, but decided to do a reinstallation of everything due
to some problems we’ve had with echos during conversations (100% SIP based,
so no ZAP echos). We are talking about a low-volume installation running off
an Intel Celeron 2.53 GHz box, 512 MB RAM and some no-name MB (HYPERLINK
"https://www.legendmemory.com/modules.php?op=modload&name=News&file=article&
sid=412"https://www.legendmemory.com/modules.php?op=modload&name=News&file=a
rticle&sid=412). The internet connection is DSL based, no NAT, eight IP
addresses.

 

The problems continued. I did some tests on the DSL line, which itself
seemed fine. But when I connected Asterisk to the network, suddenly ping
became unstable. We are talking about ping varying between 20 ms and 600 ms
over a connection that usually should result in 20 ms ping. So I decided to
eliminate the chance of increased latency due to traffic, bypassed the
switch and hooked the Asterisk box up directly to the router. I even
disabled Asterisk itself. Still, the problem persisted. It’s worth
mentioning that the latency to the router itself was fine all the time,
we’re just referring to the latency of the Asterisk box.

 

So I started installing Linux at home on a spare computer, about the same
specs, only a different motherboard (HYPERLINK
"http://www.dealtime.com/xPF-Asrock_MB_PM800_ASROCK_P4VM800_RTL_P4VM800"http
://www.dealtime.com/xPF-Asrock_MB_PM800_ASROCK_P4VM800_RTL_P4VM800). Same
issues. At this very moment, I was left with a suspicion that there might be
something with the DSL network, so I contacted the DSL provider and had them
run tests on the line, which all came out just fine. I switched DSL
modem/router, still same problems.

 

I then decided to do installations of different Linux distros (no Asterisk
installations) on the spare computer, and did some interesting observings:

- Debian: Better, only occasional (a few percentage of the pings performed
were above normal, and then only 200 ms above normal, compared to
Centos/Asterisk where 30-40% were above normal). Still not 100%

- Mandriva: Perfect latency all the way

- Centos (base installation): Problems equal to the ones described earlier

 

I did some further testing, and on a P4 3,0 GHz, 512 MB RAM and a
motherboard which I don’t know the maker /chipet, the CentOS installation
came out with just a small percentage lag in latency.

 

I have checked for IRQ errors, and there seems to be no conflicts. I do see
the network sharing IRQ with the USB bus, but this is common on motherboards
with everything integrated. 

 

I would assume this can be defined as off topic, as it clearly does not
relate to Asterisk in particular. However, I am writing this in the hope of
that someone might have had similar issues before and possibly been able to
solve the problem. Google has not given me much on the subject. It’s not
that I don’t mind putting together a new box with separate and higher level
of quality components, but I’d much rather learn something from this
experience than giving up ;)

 

 

Best regards,

Bjorn 


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