A VoIP control protocol enables the communication between the TGM550 and the routing engine on the Services Router. Ensure that the major version of the control protocol on the TGM550 and the Services Router are the same. If there is a mismatch between the major version of the protocol on the TGM550 and the Services Router, the TGM550 will not come up.
For example, if the protocol version on the TGM550 is 8.1 and the protocol version on the Services Router is 9.3, the TGM550 will not come up because of the difference in the major version of the control protocol. However, if the protocol version on the TGM550 is 8.1 and the protocol version on the Services Router is 8.4, the TGM550 will come up because there is only a difference in the minor version of the control protocol.