[asterisk-users] Maximum number of PRI calls on 1 asterisk box (no HW echo)

Wed Mar 24 22:05:19 CDT 2010

I'm running 2 Sangoma A104D cards and a Sangoma A102D card for a total
of 10 PRIs. Right now I have 9 PRIs configured as 3 DAHDI groups. 3
PRIs are in a group for local calls, 2 are grouped for long distance,
and the last 4 connect to our Toshiba PBX for users still on digital
phones.

These cards are in a Dell R710 with two quad core CPU's. System load
hovers just below 1 with 30-40 concurrent calls. Half the calls are to
SIP phones connected over OpenVPN running on the server. The other
half are DAHDI to DAHDI bridged to the PBX.

Software wise I am running CentOS 5.4 x86_64, Asterisk 1.6.1.18, DAHDI
2.2.1, libPRI 1.4.10.2, and Sangoma wanpipe driver 3.5.6. I had some
issues with newer wanpipe drivers and kernel soft locks. I also had a
PCI dma timeout issue which required a Sangoma firmware update. Since
then it has been rock solid since with 22 days of uptime.

Ryan

On Wed, Mar 24, 2010 at 9:53 PM, Zeeshan Zakaria <zishanov at gmail.com> wrote:
> In theory asterisk can handle 8 spans, which means 192 concurrent calls if
> all spans are T1. In reality after 6 spans it starts giving problems.
>
> I recently shipped a server to a client in Taiwan, and before shipment it
> was put under a load of 100 plus concurrent calls (zap channels) for two
> whole weeks without any break. It had 6 spans, Rhino T1, FXO and FXS cards
> all with on board EC. The server's processors combined were hardly 7% in use
> and no call quality issues. For the same client another server with 9 spans
> were causing asterisk to freeze once there are more than 96 calls, i.e. it
> going to 1st span of the second T1 card, which made it 9th span considering
> FXO and FXS spans, but server load remained low as usual.
>
> So I think it is not your T1 card but some software/driver issue. Did you
> upgrade anything recently on this server?
>
> --
> Zeeshan A Zakaria
>
> On 2010-03-24 8:49 PM, "James Lamanna" <jlamanna at gmail.com> wrote:
>
> Hi,
> Does anyone have any good empirical data suggesting what the maximum
> number of PRI calls (incoming and outgoing)
> without hardware echo cancellation can be handled on a single box is?
> I have a TE410P T1 (1st gen) card and I'm seeing interesting errors of
> D-Channels going down and then coming back up (See below).
>
> I've looked at the number of simultaneous calls at each of these
> points, and each time the span seems to
> have around 21-23 calls, and the total number of calls ranges between 47 and
> 53.
> I'm trying to figure out if this is a load issue or an issue on the
> provider side, though my provider says they
> do not see any errors on any of the T1s.
> Could this be some sort of hardware interrupt problem? If so, how can I
> check?
>
> The specs of the machine are, Dual Xeon 2.80Ghz (both single core but w/HT)
> 4GB memory.
> Running asterisk 1.4.26.3 (32-bit)
> with libpri-1.4.7 and zaptel-1.4.12.9
>
> Thanks.
>
> -- James
>
> Please CC me on responses.
>
>
> [Mar 22 09:45:00] VERBOSE[8887] logger.c:   == Primary D-Channel on span 2
> down
> [Mar 22 09:45:00] WARNING[8887] chan_dahdi.c: No D-channels available!
>  Using Primary channel 48 as D-channel anyway!
> [Mar 22 09:45:00] VERBOSE[8887] logger.c:   == Primary D-Channel on span 2
> up
> [Mar 22 09:59:23] VERBOSE[8886] logger.c:   == Primary D-Channel on span 1
> down
> [Mar 22 09:59:23] WARNING[8886] chan_dahdi.c: No D-channels available!
>  Using Primary channel 24 as D-channel anyway!
> [Mar 22 09:59:23] VERBOSE[8886] logger.c:   == Primary D-Channel on span 1
> up
> [Mar 22 09:59:23] VERBOSE[8886] logger.c:   == Primary D-Channel on span 1
> down
> [Mar 22 09:59:23] WARNING[8886] chan_dahdi.c: No D-channels available!
>  Using Primary channel 24 as D-channel anyway!
> [Mar 22 09:59:23] VERBOSE[8886] logger.c:   == Primary D-Channel on span 1
> up
> [Mar 22 10:36:11] VERBOSE[8886] logger.c:   == Primary D-Channel on span 1
> down
> [Mar 22 10:36:11] WARNING[8886] chan_dahdi.c: No D-channels available!
>  Using Primary channel 24 as D-channel anyway!
> [Mar 22 10:36:11] VERBOSE[8886] logger.c:   == Primary D-Channel on span 1
> up
> [Mar 22 10:36:11] VERBOSE[8886] logger.c:   == Primary D-Channel on span 1
> down
> [Mar 22 10:36:11] WARNING[8886] chan_dahdi.c: No D-channels available!
>  Using Primary channel 24 as D-channel anyway!
> [Mar 22 10:36:11] VERBOSE[8886] logger.c:   == Primary D-Channel on span 1
> up
> [Mar 22 10:44:36] NOTICE[8888] chan_dahdi.c: PRI got event: HDLC Bad
> FCS (8) on Primary D-channel of span 3
> [Mar 22 10:45:44] NOTICE[8886] chan_dahdi.c: PRI got event: HDLC Bad
> FCS (8) on Primary D-channel of span 1
> [Mar 22 10:59:33] NOTICE[8887] chan_dahdi.c: PRI got event: HDLC Abort
> (6) on Primary D-channel of span 2
> [Mar 22 11:30:53] VERBOSE[8886] logger.c:   == Primary D-Channel on span 1
> down
> [Mar 22 11:30:53] WARNING[8886] chan_dahdi.c: No D-channels available!
>  Using Primary channel 24 as D-channel anyway!
> [Mar 22 11:30:53] VERBOSE[8886] logger.c:   == Primary D-Channel on span 1
> up
> [Mar 22 15:34:28] VERBOSE[8887] logger.c:   == Primary D-Channel on span 2
> down
> [Mar 22 15:34:28] WARNING[8887] chan_dahdi.c: No D-channels available!
>  Using Primary channel 48 as D-channel anyway!
> [Mar 22 15:34:28] VERBOSE[8887] logger.c:   == Primary D-Channel on span 2
> up
>
> --
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