An apparatus and method for managing clock domain(s) crossing several communication networks are disclosed. In one embodiment, a process capable of managing clock domains receives a data stream over a circuit emulation service (“CES”). Upon storing the data stream in a traffic buffer, the process selects a first clock domain for processing the data stream in the traffic buffer. For example, the process is capable of using the first clock domain to process and/or empty a jitter buffer, which stores CES data packets. The traffic buffer is monitored and the first clock domain can be replaced with a second clock domain if the storage capacity of the traffic buffer indicates that a different clock domain is needed.