P-Cycle protection at the glass fiber level

Abstract

The cost and complexity of wavelength assignment, wavelength conversion and wavelength-selective switching are always of primary considerations in the design of survivable optical networks. This proposal recognizes that as long as the loss budgets are adequate, entire DWDM wavebands could be restored with no switching or manipulation of individual lightpaths; so that the DWDM layer would never know the break happened. And environments where fiber switching devices are low cost, and ducts are full of dark fibers provide a very low cost alternative to protect an entire DWDM transport layer (or working capacity envelope) against the single largest cause of outage. Yet, while nodes and single DWDM channels may fail, a pre-dominant source of unavailability is the physical damage of optical cables. Thus, with the objectives of reducing the overall real CapEx costs and removing the complexity due to wavelength assignment and wavelength continuity constraints when configuring p-cycles in a fully transparent network context, this paper addresses the subsequent questions: if it is ultimately glass that fails, what if just the glass is directly replaced? 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?