[Asterisk-Users] MGCP parameters

[Jayson Vantuyl]

On Fri, Dec 31, 2004 at 10:03:54AM -0300, Leonardo J. Tramontina wrote:
> 1) I am using Asterisk and a softphone called MGCP eyeP Phone. I was 
> watching the traffic between them at Ethereal and observed that some of 
> them have extra parameters. Example: CreateConnection has "Request 
> Identifier (X)", that is not described on RFC 2705. Should I ignore or 
> consider it?
I believe X is spec'd in RFC 3435.
> 
> 2) There are some parameters that don't have identifier? I mean, "Request 
> Identifier" is "X:"; "Observed Events" is "O: "; "Call ID" is "C: "... 
> These are them:
> - "Notified Entity"
> - "Remote Connection Descriptor"
> - "encapsulated Endpoint Configuration"
> - "Second Endpoint Id"
> - "encapsulated Notification Request"
See above.

> 2.1) How can I identify them when they exist?
See above.  RFCs 2705 and 3435 both specify how to handle unknown
commands and parameters.

> 2.2) What means "encapsulated" parameters??
When you receive a RQNT (request for notify) you include the action to
be taken for different types of events.  The action can be a stripped
down RQNT that provides new instructions, just like a new RQNT packet.
This can include parameters.  I've heard it call encapsulated parameters
but I believe that the spec calls it embedded.  YMMV.

FWIW, Asterisk's MGCP support is a bit dubious and definitely not what
the spec intended.  The spec intended for a call agent to manage various
media gateways and orchestrate what was going on.  Asterisk is a media
gateway that attempts to be a call agent for itself and another media
gateway (the phone) with interesting but limited results.  It probably
will never operate in a real MGCP environment unless chan_mgcp is
implemented as a media gateway.  Right now, it just provides a hack that
allows MGCP phones to hit it...sometimes.  Good luck.

-- 
Jayson Vantuyl