asterisk users - Jul 2005 - HDLC bad FCS

I have 2 servers, configured identically. Each has a TE405P and 2 PRIs. One
server was experiencing crackly audio on one circuit, accompanied by HDLC
bad FCS messages. The telco recabled and moved me to another port on the
DMS-100. The audio is better, but there are still bad FCS problems on the
span. I have moved the PRI in question to the other server, and the problem does
indeed move with the circuit.

There are no zaptel timing/interrupt problems present on either server. The fact
that 3 PRIs are error free and that the problem moves with the
circuit tells me that there is still a problem on the circuit.

The telco believes that there is nothing more that they can do (provision a
complete new circuit?).

I don't get HDLC aborts, so the problem may not be _that_ serious. Does
anyone have any comments? Would a newer (unstable) version of Zaptel drivers
help? Would line-build-out parameter in zaptel.conf make any difference?

I believe that you need to analyze the packets at your provider site. They
should be able to do that. Is your HDLC located on your location or on your
provider. This test should be done where Asterisk is running, because is
where the problem is reported.

Start to look for Line Analyzers for HDLC, in order to check BER.

If BER is high enough, then the problem is internal on your server.

Regards,

Carlos Alperin
Senior System Engineer 
Seneca Communications, LLC
Calperin@senecacom.net 

-----Original Message-----
From: asterisk-users-bounces@lists.digium.com
[mailto:asterisk-users-bounces@lists.digium.com] On Behalf Of Rod Bacon
Sent: Monday, July 04, 2005 7:27 PM
To: asterisk-users@lists.digium.com
Subject: [Asterisk-Users] HDLC bad FCS

I have 2 servers, configured identically. Each has a TE405P and 2 PRIs. One
server was experiencing crackly audio on one circuit, accompanied by HDLC 
bad FCS messages. The telco recabled and moved me to another port on the
DMS-100. The audio is better, but there are still bad FCS problems on the 
span. I have moved the PRI in question to the other server, and the problem
does indeed move with the circuit.

There are no zaptel timing/interrupt problems present on either server. The
fact that 3 PRIs are error free and that the problem moves with the 
circuit tells me that there is still a problem on the circuit.

The telco believes that there is nothing more that they can do (provision a
complete new circuit?).

I don't get HDLC aborts, so the problem may not be _that_ serious. Does
anyone have any comments? Would a newer (unstable) version of Zaptel drivers

help? Would line-build-out parameter in zaptel.conf make any difference?
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