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

[Dan Austin]

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?  

> 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 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.

> 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...

Dan