An apparatus and method for managing and characterizing clock domains in multi-domain networks are disclosed. A process of clock domain management is capable of receiving a data packet or data stream traveling across CES circuit. Upon obtaining a clock domain hierarchy stored in a storage location, the process identifies a clock frequency in the clock domain hierarchy in accordance with the CES circuit. The clock domain hierarchy, in one embodiment, is a searchable database containing information relating to clock domains. The clock frequency is subsequently assigned to a packet processing unit for data processing.