[Asterisk-Dev] Petition for IAX firmware

[Mike Taht]

> Cool.  I've been curious to see if anyone has run asterisk on the
> IXP425.  

Been running it for a couple months now. the (small number of) patches
required went into CVS head a couple weeks back.

>Out of curiosity, have you used the HSS interface using the
> intel access library to do PSTN interfacing through the SiLabs SLIC?

Ah, there's a rub. The intel access library has a non-gpl compatible
license, and only works on the 2.4 kernel. It's a bletcherous port
from a vxworks product, without a clean interface to userspace, and it
is well despised (see item #2 in
http://www.arm.linux.org.uk/mailinglists/faq.php).

Not using it is as problematic as using it.

Given that asterisk already had some support for these slics we
thought about bypassing the access library and porting the zaptel
stuff over.

At one point, we had trinity convergence's phone gateway software
talking to the slics and talking to asterisk via localhost. Trinity's
sip support was awfully primitive, and the phone quality nowhere near
as a good as a dedicated sip phone...

In the final evaluation we decided that everybody else was thinking
that the analog->voip port market was going to explode, and we didn't
need to be part of the debris. So we dropped the slics, put a big (but
optional) memory mapped FPGA on the board, brought out the HSS port
and 60 other pins,  and connected the FPGA up to another board... to
do something really neat that hasn't been done before that I can't
talk about in this forum, yet.

> Also, have you used DSR to do codec accelerations or are you just
> letting Asterisk do it native?

See aformentioned licencing issue.

Just letting asterisk do it native. The Xscale is one of the fastest
embedded chips out there - aside from needing to one day soon replace
the floating point routines in the tone generator and maybe in plc.c,
it keeps up with a lot of sip/iax phones at our desired level of
loading (which is less than a T1) on the gsm, ulaw and slinear codecs.
The arm-integer only version of speex 1.1.7 is eating about 10% of cpu
going to slinear. G726 is pretty good, but I haven't measured it. I'm
told there's an int only reference stack for G729...

(I keep thinking that in higher loaded situations the real issue is
not the codec path but the threading overhead of linuxthreads vs nptl.
anybody have hard data on asterisk on linuxthreads vs nptl)

Now, if we were to shoot for 4T1s off the board, and willing to shift
a lot more work to kernel space than we currently do, and cross
license the code so that both Intel and Digium would be happy... to
enter the really small pbx market as say a competitor to panasonic -
with like a ton of funding - then using the full access library and
the DSR routines becomes more appealing.

If intel would GPL those libs, tho' - they would make a lot of people
happy. TI is trying to enter the voip gw market too, yet their analog
gw for linux has a lot of crazy licenses wrapped around it. A TI rep
stared at me blankly when I told them I wanted to run asterisk on
their board, and then told me all about their high quality DSP
implementation of g723, and wouldn't let me touch their command line
client for fear of crashing it.

After wrestling with the Intel access library and with intel and all
the pain of trying to build a product around legal limitations, and
being stuck with an ancient port of Linux 2.4 - I've been spending my
relaxing time with the EP9302. What I'd like to be doing next is
creating a small voip pbx/answering machine/ivr/X10/mp3 toy out of a
ts-7250, on 2.6, with hw floating point.

> Coyote isn't too cheap, but it is meant to be a reference board. There
> are several companies who have built mass market solutions that sell
> for a lot less on the same architecture.  eg. Netgear's wireless VoIP
> box for AT&T Callvantage (retail < $200) but I am not sure if it can
> be reprogrammed or not.

Yep. Don't know if it can be reprogrammed yet, either.

Another board that's interesting is the Slug, also the openwrt. 


-- 
Mike Taht
PostCards From the Bleeding Edge
http://the-edge.blogspot.com