NOWADAYS, the spectrum-sliced elastic optical networking based on the optical orthogonal frequency-division multiplexing (O-OFDM) technology has attracted intensive research interests as it can improve the spectral efficiency of the optical layer significantly Dynamic p-Cycle Protection in Spectrum-Sliced Elastic Optical Networks with flexible bandwidth allocation. Unlike the wavelength-division multiplexing (WDM) networks that operate on discrete wavelength channels with a bandwidth of 50 or 100 GHz, the O-OFDM networks groom the capacities of a few narrow-band subcarrier channels (frequency slots) that are spectrally contiguous and achieve high-speed data transmission over them. Dynamic p-Cycle Protection in Spectrum-Sliced Elastic Optical Networks Hence, by adjusting the number of assigned frequency slots (FS’) to each lightpath, O-OFDM networks can allocate optical spectrum with a finer granularity and agile bandwidth management for different network applications can be achieved. To this end, people refer the optical networks based on the O-OFDM technology as elastic optical networks (EONs) . Dynamic p-Cycle Protection in Spectrum-Sliced Elastic Optical Networks Previously, researchers have investigated the routing and spectrum assignment (RSA) of lightpaths intensively for realizing efficient service planning and provisioning in EONs . However, most of these studies did not consider how to setup Dynamic p-Cycle Protection in Spectrum-Sliced Elastic Optical Networks lightpath connections with protection or restorability. It is known that in optical networks, the amount of service disruption and data loss caused by a network-related outage can be huge , because a single optical fiber can carry over 20 Tb/s transmission capacity . Meanwhile, natural disasters and other factors can trigger unpredictable failures of network elements and make network survivability a serious issue . Dynamic p-Cycle Protection in Spectrum-Sliced Elastic Optical Networks In EONs, a link failure may lead to more severe service disruption due to the higher data-rate provided by the supper-channels. Therefore, it is not only important but also necessary to study the protection schemes for EONs, and the network operators need to implement them to ensure certain service availability for the lightpath connections. The authors of proposed an SPP scheme for EONs, which was called elastic separateprotection- at-connection and could realize spectrum sharing by using first-fit to assign working traffic and last-fit to assign backup traffic.