The durable products of prior art woodworking have always been unyielding constructions of individual wooden elements held and forced rigidly in place by rigid means such as joinery, fasteners, adhesives, or supporting structures. This spectral shaping can reduce performance degradation by Kerr effect optical non linearities. The negotiating includes indicating a capability of a communication network node to expand bandwidth by indicating support of the communication network node for a wideband codec towards another communication network node; and indicating a lack of codec transparency for the wideband codec at the communication network node.