Abstract: A method of detecting signal degrade in an ATM network, and a network element using such method are disclosed. Signal degrade at the ATM layer of the network is detected by monitoring signal degrade at the physical layer of the network. In response, ATM cells indicative of the signal degrade may be generated at the ATM layer, and protection switching may be effected. Preferably, signal degrade at the physical layer may be monitored by determining a bit-error-rate at the physical layer. ATM alarm indication signal (“AIS”) cells or ATM protection switching coordination protocol (“CP”) cells may be generated to effect the protection switching.