在彈性光網路中，保護機制是相當重要的一個議題，因為在網路傳輸過程中有機率會發生網路損壞的事件，導致傳輸中斷，所以除了一般進行資料傳輸的工作路徑，還需要執行繞徑與頻譜配置找出備用路徑，便可在網路損壞之際從工作路徑切換至備用路徑，保證傳輸不中斷。
在一般的保護機制相關文章中，在模擬時，資料傳輸的要求發出，演算法便會尋找工作路徑以及備用路徑，任一路徑只要無法找到其繞徑或頻譜的配置，便會阻斷此要求；相反的成功配置之後便是演算法的結束，每一個資料傳輸的要求都經過演算法的計算，模擬便結束，再來則是去觀察相關數據對應到其演算法和不同策略的表現。這樣的做法雖然可以觀察到演算法及策略對於網路資源的影響，卻不能完整的呈現出保護機制的特點，因為並沒有把最初保護機制的假設，單一鏈結損壞考慮進模擬環境，所以雖然為每一個傳輸要求找出工作及備用路徑，備用路徑卻只是用來佔據網路資源而無傳輸任何資料，也沒有把網路損壞後的應變情況考慮進去。如果只是在網路鏈結損毀後，單純地將工作路徑切換路徑，這樣的保護機制是不完整的。因此，我們提出了一個備用路徑的重整演算法，可以搭配任意的備用路徑保護演算法，為的是要解決網路鏈結發生損壞之後的狀況。當工作路徑切換到備用路徑後，傳輸要求就被暴露在隨時會因為鏈結損壞而導致傳輸中斷的風險之下，若是使用共享備用路徑演算法，在演算法配置時節省了許多網路資源，這時候便需要花更多的時間來重新配置那些共享的備用路徑。此外，我們也在模擬加上單一網路鏈結損壞的機制，觀察不同的單一網路鏈結損壞機制對於網路資源以及演算法和策略上造成的影響。

Protection is a very important issue in elastic optical networks (EONs) because the link failure may result in transmission interruption and blocked. In a complete protection scheme in EONs, the routing, modulation format and spectrum assignment (RMSA) problem has to be solved not only for working paths but also for backup paths and then optical paths should be switched from working paths to backup paths while the network is suffering link failure so that that the transmission interruption can be avoided.
In literatures related to protection in EONs, only the RMSA issue for both working paths and backup paths in provisioning stage is investigated and discussed. However, in addition to optical path switching from working paths to its corresponding backup paths, further indispensable processing in response to such a change of configuration is always ignored. Therefore, we propose a shared backup path protection (SBPP)-based backup optical path reconfiguration, which can match any SBPP-based backup path RMSA algorithm to handle the situation after link failed. Actually, after an optical path switches from working path to its backup path it is exposed under the risk of being interrupted if the next link failure occurs. Furthermore, if the RMSA of backup paths are based on SBPP scheme to save more resource as compared to dedicate backup path protection (DPP), it requires more time to reconfigure backup paths sharing common resources. Finally, we build up a simulation environment under the single link failure assumption to observe the performance of various backup path reconfiguration algorithms.

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[13] Availability https://en.wikipedia.org/wiki/High_availability
[14] Mean Time Between Failure https://zh.wikipedia.org/wiki/%E5%B9%B3%E5%9D%87%E6%95%85%E9%9A%9C%E9%96%93%E9%9A%94