It is disclosed a network element for a communication network configured to synchronize its local clock to a reference clock signal. The network element comprises: a main board comprising an internal module configured to support an internal synchronization transport protocol, and a connector connected to the internal module; and a pluggable module configured to be removably connected to the connector. The pluggable module is configured to, when connected to the connector: exchange external synchronization information with a further network element, the external synchronization information being formatted according to an external synchronization transport protocol different from the internal synchronization transport protocol; exchange with the internal module internal synchronization information formatted according to the internal synchronization transport protocol; and interface the internal synchronization transport protocol and the external synchronization transport protocol.