[asterisk-users] Can Asterisk bridge between a SIP client and a Cisco Call Manager server?

[Shocky]

On Friday 10 April 2009 10:53:17 Dan Austin wrote:
> Shocky wrote:
> > This is probably outside what Asterisk is intended for, but I'm hoping it
> > can help.
> >
> > I need to make and receive calls through a Cisco Call Manager server that
> > I have no control over. I have to use a Cisco soft phone (Cisco IP
> > Communicator), which only runs on Windows. But I'm on Linux. CCM is
> > apparently capable of supporting SIP and H.323 interfaces, but they won't
> > provide this option for me. Right now I'm using a VMWare XP guest to run
> > the soft phone, but this is painful (especially with some VPN
> > complications thrown in).
>
> It maybe a small nuance, but as a CCM administrator I can understand the
> refusal to support a roaming H323 or SIP endpoint on CCM.  Perhaps if your
> asterisk box was not mobile, the CCM admins would consider a H323 trunk to
> your system?

No, I'm not mobile. I telecommute from home. I'm not sure what the reasoning 
is behind the restriction. Since it's all within the VPN it shouldn't be a 
security issue. They won't do anything custom for me (they have thousands of 
users, so probably wouldn't have time). They did say that they are aware of 
the non-Windows issue, and might eventually provide a solution. 

I don't know why Cisco won't support Linux, since IP Communicator is written 
in Java. But nothing I can do about that either.


> > I've read that Asterisk supports SCCP, at least somewhat. I'm wondering
> > if I could set up Asterisk on my desktop machine to route calls between a
> > SIP client such as Kphone or Ekiga and the CCM server. Would this be
> > possible?
>
> The SCCP support in Asterisk is currently limited to asking as a SCCP
> server, not as an SCCP client.  So you cannot use Asterisk to register as a
> phone to CCM.  The SCCP protocol does have a 'trunking' mode, but Cisco
> barely uses it themselves, and it is geared to low density situation,
> two-four channels. I am not aware on any effort to duplicate that in
> chan_skinny.  It is conceivable that chan_skinny could be taught to emulate
> a Cisco endpoint (7965 for example), but the end result would be of limited
> value.  It would have a limited number of lines/channels and the protocol
> in this use model would not support passing destination information, so it
> would require a 1-to-1 mapping of a CCM extension to an Asterisk extension.

I only need one line, from my desktop to the CCM server.

I'm not sure what might be involved in trying to adapt the chan_skinny code to 
act as an SCCP client. I've never worked with any VoIP code before. I might 
be an interesting project to try to merge the chan_skinny code with some SIP 
client to make an SCCP client. But I'm not sure I'd have time to do it

And if I did it on my employer's network, it would end up belonging to them, 
which would not be a desirable result - if I did it, I would want to release 
it to the community. Anyone have a CCM server I could legally experiment 
against without creating code ownership problems?


> > I heard that one of the problems in interfacing with CCM over SCCP is the
> > use of proprietary codecs. Would this be a problem in my case?
>
> Not quite true.  SCCP is a proprietary protocol, but the codecs supported
> match well with what Asterisk offers, at least the codecs you would likely
> choose to use.

Well, that's one bit of good news at least.


> > If there's a chance it can be made to work, I'll give it a try. If I'd be
> > wasting my time, please let me know.
>
> There is a chance, but it depends on working with the CCM admins and how
> willing they are to create a one-off configuration for you...

That means no chance in my case. Oh well.


> Dan

Thanks for the clarification Dan.

Shocky
-- 
These are my opinions. Get your own.