Cisco ASR 900 Series Ethernet interface modules are designed to give customers a high degree of flexibility and value. All Ethernet interface modules share a common core that supports time stamping on the module for Y.1731 operations, administration, and maintenance (OAM) delay measurement functions to achieve precise results for one-way and two-way delay measurement. The modules also provide time-stamping functions for the IEEE 1588-2008 protocol. These time stamps help ensure that the Cisco ASR 900 Series Aggregation Services Routers achieve outstanding results when deploying IEEE 1588-2008 protocols for frequency and phase synchronization. Not all customers will deploy IEEE 1588-2008 for synchronization; therefore, the Ethernet interface modules also support input and output frequency synchronization using synchronous Ethernet (SyncE).All Cisco ASR 900 Series Ethernet interface modules support online insertion and removal (OIR), which contributes to a higher uptime for the Cisco ASR