asterisk users - May 2010 - Sometimes called party answers, but callee keep hear ringing, called party hears nothing!

Hi,

As mentioned we have the problem that sometimes (could be up to a view times a
day) for the calling party (SIP Device) you here ringing. The called party
however answered the phone, but hears nothing. The calling party keeps ringing
until the phone is hangup.

First I thought maybe the card or the server has a problem, so I changed from a
PCI beronet 4bri to a Junghanns 4bri PCIexpress and changed the server (as it
was on a spare server anyway) from an old HP ProLiant DL360 G3 to an Dell
PowerEdge 1850 with PCIe riser card.

But the issue remains, it never occured with the old Siemens Hipath 3000! There
are approx. 14 active phones and 6 analog devices connected to a Sipura SPA
3000. The Problem originates from the SIP Phones (can not tell about the analog
devices, but they are, from asterisk standpoint, SIP as well). I experienced
this behavior a few times as well.

Log entries show nothing peculiar, but I also do not have Zap/Dahdi debugging
active. The call get's passed to the DAHDI Device and there are no further
indications of problems.

Please tell me if more information is needed to fix this behavior, as this is in
my experience not normal (other Asterisk solutions I administrate work fine). We
are located in Spain, if this matters.

we have an ubuntu server 32bit, stock ubuntu asterisk and dahdi:

asterisk, 1:1.6.2.5-0ubuntu1
dahdi, 1:2.2.1-0ubuntu2

We have 4 ISDN lines, currently 3 lines connected.

Some are connected as bri_cpe (from the former input to a Siemens HiPath 3000),
and some as bri_cpe_ptmp.
Span 2 currently not connected.


Span configuration:
; Span 1: B4/0/1 "B4XXP (PCI) Card 0 Span 1" (MASTER) AMI/CCS 
group=0,11
context=from-zaptel
switchtype = euroisdn
signalling = bri_cpe
channel => 1-2
context = default
group = 63

; Span 2: B4/0/2 "B4XXP (PCI) Card 0 Span 2" AMI/CCS RED
group=0,12
context=from-zaptel
switchtype = euroisdn
signalling = bri_cpe_ptmp
channel => 4-5
context = default
group = 63

; Span 3: B4/0/3 "B4XXP (PCI) Card 0 Span 3" AMI/CCS 
group=0,13
context=from-zaptel
switchtype = euroisdn
signalling = bri_cpe
channel => 7-8
context = default
group = 63

; Span 4: B4/0/4 "B4XXP (PCI) Card 0 Span 4" AMI/CCS 
group=0,14
context=from-zaptel
switchtype = euroisdn
signalling = bri_cpe_ptmp
channel => 10-11
context = default
group = 63

; Span 5: DAHDI_DUMMY/1 "DAHDI_DUMMY/1 (source: HRtimer) 1" 



Best,
Ray