We disclose a network element having one or more OAM components that enable the network element to send and receive in-band service messages without disrupting the flow of user data on the wavelength channel(s) used for the transmission of said in-band service messages. When deployed in a transport plane of a communications network, a plurality of such network elements can advantageously be used to perform various OAM functions that support a link-fault-management mechanism in a manner that complements and strengthens the existing OAM capabilities, particularly at various intermediate points within the optical network path(s).