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

[Zeeshan Zakaria]

Tzafrir, so you have actually worked with more than 192 concurrent zap
channels, which means more than 8 spans, on a single server, and can verify
that it actually works without freezing asterisk.

I really need specs for this system. I'll recompile zaptel, no problem, but
it'll save me one extra server, for a customer for whom I am doing the
implementation these days. I'll get the new cards as well, though Rhino
cards are very good cards, but I need more spans per server, which will
actually work in production not freezing asterisk.

--
Zeeshan A Zakaria

On 2010-03-25 1:45 PM, "Tzafrir Cohen" <tzafrir.cohen at xorcom.com> wrote:

On Thu, Mar 25, 2010 at 10:24:41AM -0600, Carlos Chavez wrote:
> On Thu, 2010-03-25 at 17:11 +0100, ...
The "limit" of 250 (actually 249. It was 250 originally and changed to
249 when /dev/zap/transcode was introduced) zap channels is only that of
the device files that are generated. But userspace programs normally use
/dev/dahdi/channel to ask for a channel (using the ioctl DAHDI_SPECIFY)
and don't need to open /dev/dahdi/NNN directly (but if that really
bothers you, that limitation has been removed in the branhc
/team/tzafrir/sysfs ).

Asterisk, though, has an arrach of 32 'spans' (PRI spans). This means
that if you try using a PRI span number whose number >= 32 you'll get an
annoying error.

Someone who encontered that error early on was KP Junghanns. He added
support for BRI devices to chan_zap. Thus he had much smaller spans. And
could afford inclding many of them (a single octobri card has 8 spans).
Which is why the bristuff patch includes the following:

-#define NUM_SPANS              32
+#define NUM_SPANS              128     /*!<"32 spans", muahahaha, us alaws
like to have some more... */

In the Debian package I incllude a slightly different variant of it:

-#define NUM_SPANS              32
+#define NUM_SPANS              DAHDI_MAX_SPANS

As you can see, there's actually a limit at the DAHDI level.
DAHDI_MAX_SPANS, which is 128. Likewise there's DAHDI_MAX_CHANS which is
1024. That's as many channels that you can have.

(Disclaimer: I may be off by one here and there, as DAHDI span numbers
and channel numbers are 1-based rather than 0-based)

If you need more, you'll just have to rebuild DAHDI (been there, done
that ;-)

--
              Tzafrir Cohen
icq#16849755
jabber:tzafrir.cohen at xorcom.com<jabber%3Atzafrir.cohen at xorcom.com>
+972-50-7952406           mailto:tzafrir.cohen at xorcom.com
http://www.xorcom.com  iax:guest at local.xorcom.com/tzafrir

--

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