Monthly Archives: June 2010

Hardware Conferencing in SRST mode (CBarge)

In a scenario where a customer wants to enable Hardware conferencing while in SRST for CBarge as well as in normal operation. We can configure this by registering the conference bridge first to the Call managers and then to the telephony service IP source address. In this way when the gateway will go in SRST,ContinueContinue reading “Hardware Conferencing in SRST mode (CBarge)”

MGCP Gateway Setup

MGCP Configuration Using Trombone Feature: To register an MGCP gateway to call manager, follow these steps: Do a show inventory OR show diag to check the position of E1/T1 Enable the E1/T1 by using command – card type T1 0 0 OR card type T1 0 1 (whatever the case may be) Do show verContinueContinue reading “MGCP Gateway Setup”

MGCP Call Flow – ISDN PRI

In a typical ISDN setup for an Inbound call from PSTN to an IP phone (-SCAC-) CCM  –  GW  – PSTN Setup <——- Call proceeding ——-> Alerting ——-> Connect ——> Gateway and PSTN switch exchange Q921 Layer 2 information. Gateway registers with ISDN switch and terminates Q921 at gateway. A Q931 Setup message arrives. TheContinueContinue reading “MGCP Call Flow – ISDN PRI”

MGCP – How it works?

General: MGCP stands for Media Gateway Control Protocol. It’s a client-server protocol which means that it has  to depend on Media Controller (Call agent) for call routing. In case of Cisco this MC is a CUCM. The Call agent controls the ports of a MGCP gateway. UDP Port 2427  is used for communication between CallContinueContinue reading “MGCP – How it works?”

Signalling & Call Set-up

Signalling and Call set-up There are three types of Signalling: 1) Supervisory: On-hook, off-hook, Ringing 2) Address: Communicates the digits that were dialed like DTMF (Dual tome multi frequency) and Pulse dialing 3)Informational: Dial-tone, ring-back tone, recorder tone. Call set-up: 1.The calling phone goes off-hook, closing the circuit to the local CO switch. 2. TheContinueContinue reading “Signalling & Call Set-up”