We report the first experimental realization of dynamically reconfigurable ultra-longhaul network using "broadcast and select" optical add-drop-multiplexer (OADM) architecture. We achieve 80 x 10.7 Gb/s nonreturn-to-zero C-band dense wavelength-division-multiplexing networking with 50-GHz channel spacing over 4160 km (52 spans x 80 km each) of all-Raman-amplified symmetric dispersion-managed fiber and 13 concatenated OADMs with 320-km spacing. Measured Q values exhibit more than 2 dB margin over the forward-error-correction threshold for 10 15 bit-error-rate operation. These results are obtained for the channels. passing through the 320-km spaced OADMs when 50% add-drop occurs at an intermediate OADM located along the transmission path, as well as for the channels added at the intermediate OADM. Penalties due to filter concatenation and crosstalk are quantified. Q factor is also characterized after 8000-km transmission.