What role does the call agent play when using an MGCP gateway?
A call agent is essential when you are using an MGCP gateway. It knows the dial plan, so it tells the gateway where to route calls. It controls the setup and teardown of connections to endpoints on the gateway, and thus the setup and teardown of calls.
List the control messages that MGCP uses.
How does MGCP Backhaul function?
The gateway terminates ISDN Q.921 messages but places the Q.931 messages in a TCP packet and sends them to the CallManager for processing.
What three commands do you need to enable MGCP on a router and identify Cisco CallManager as its call agent?
mgcp call-agent [ip-address|hostname] [port] 5ccm-manager mgcp
Why is there a need for DTMF relay in a VoIP network, regardless of the gateway protocol used?
When you are using codecs that compress voice, DTMF tones might become distorted or part of the signal might be lost. Then the receiver would not be able to respond correctly to the numbers that were sent.
Part I: Voice Gateways and Gatekeepers
Gateways and Gatekeepers
Part II: Gateways
Media Gateway Control Protocol
Session Initiation Protocol
Connecting to the PSTN
Connecting to PBXs
Connecting to an IP WAN
Influencing Path Selection
Configuring Class of Restrictions
SRST and MGCP Gateway Fallback
Using Tcl Scripts and VoiceXML
Part III: Gatekeepers
Part IV: IP-to-IP Gateways
Cisco Multiservice IP-to-IP Gateway
Appendix A. Answers to Chapter-Ending Review Questions