Abstract: A method and apparatus for transporting a supercarrier signal over a network span is described. The apparatus includes a network for transporting the supercarrier signal, which includes messaging information, using a first protocol. The apparatus further includes a network span comprising a plurality of low bit rate network sections for transporting a plurality of trib signals using a second protocol, and a transparent demultiplexer connected to the network and the network span for demultiplexing the supercarrier signal into the trib signals. The demultiplexer is arranged to insert into the plurality of trib signals the messaging information required to maintain said first protocol. The apparatus also includes a multiplexer, connected between the network span and the network, for transparently multiplexing the trib signals into the supercarrier signals. Also described is a transparent multiplexer and a transparent demultiplexer.