Whole fiber switched p-cycles

Abstract

In the design of survivable optical networks, the cost and complexity of wavelength assignment and conversion and wavelength-selective switching is always a dominant consideration. And yet, while nodes and single DWDM channels may fail, a pre-dominant source of unavailability is physical damage to optical cables. Thus, we have considered: If it is ultimately glass that fails, what if we just replace the glass directly? More specifically, what if p-cycles were used to rapidly, simply and efficiently provide for the direct replacement of failed fiber sections with whole replacement fibers? As long as the loss budgets are adequate, entire DWDM wavebands could be restored with no switching or manipulation of individual lightpaths. Following a substitution transient, the DWDM layer would never know the break happened. In environments where fiber switching devices are low cost, and ducts are full of dark fiber, this could provide a very low cost alternative to protect an entire DWDM transport layer (or working capacity envelope) against the single largest cause of outage. Here, we make a first proposal of considering this approach. A main motivation is to remove the complexity due to wavelength assignment and wavelength continuity constraints when configuring p-cycles in a fully transparent network context. Another objective is the overall real CAPEX and OPEX cost reductions.