Cisco Cisco IOS Software Release 12.2(2)XA

To enable piggyback messages, use the mgcp piggyback message global configuration command. To 
disable piggyback messages, use the no form of this command.

This command has no keywords or arguments.

Piggyback messages are enabled.

Global configuration

Use this command to disable piggyback messages for MGCP 1.0, NCS, and TGCP when a network 
gateway cannot handle piggyback messages. Piggyback messaging is not available to SGCP and 
MGCP 0.1.

The term piggyback message refers to a situation in which a gateway or a call agent sends more than 
one MGCP message in the same UDP packets. The recipient processes the messages individually, in the 
order received. However, if a message must be retransmitted, the entire datagram is resent. The recipient 
must be capable of sorting out the messages and keeping track of which messages have been handled 
or acknowledged.

Piggybacking is used during retransmission of a message to send previously unacknowledged messages to 
the call agent. This maintains the order of events the call agent receives, and makes sure that RSIP 
(RestartInProgress) messages are always received first by a call agent.

The following example illustrates how to disable piggyback messages:

Router(config)# no mgcp piggyback message

12.2(2)XA

This command was introduced.

Starts and allocates resources for the MGCP daemon.