The transmission of energy is monitored in the smart grid through deploying sensors in all the components, including the overhead transmission lines. There are many poles/towers supporting a long overhead transmission line. Naturally, sensors are deployed on the location close to the poles/towers on each span. Due to the limited transmission range of the wireless transceiver module of a sensor, researchers generally assume that data generated by a sensor have to be delivered to the substation through a set of sensors in-between. This results in a linear network model. In this paper, we first analyze the performance of this model in handling the traffics extracted from an existing testbed. We realize that the linear network model may not be sufficient to support future smart grid applications which may have diversified requirements on data delivery. We then study a new network model in which sensor/relay nodes can also communicate with other nodes using a wide area network such as the cellular network. In this new model, the network formed can be reconfigured based on the application requirements to deliver information to the substations efficiently and effectively.

We observe that the performance of wavelengthrouted (WR) networks often suffers from asymmetric traffic and network traffic patterns differing from the original design plans. WR networks with a fixed number of channels in a given transmission direction are inflexible. Therefore, we propose reversible wavelength channels. Like a reversible lane in highway systems, a reversible wavelength channel has the flexibility of its transmission direction being configurable at the setup of a lightpath. So far reversible wavelength channels have not been discussed in WR networks even though we observe that most of the required technologies are already available. In this paper, we discuss all the required technologies for implementing reversible wavelength channels in WR networks. We demonstrate that reversible wavelength channel can provide significant performance improvement for WR networks when the traffic is asymmetric. Even if the traffic is symmetric, we also have nontrivial performance improvement with reversible wavelength channels, i.e., the blocking performance of WR networks with reversible wavelength channels will be similar to that of normal WR networks with doubling the number of fibers per link. Different implementation approaches for reversible wavelength channels are discussed. Among them, the performance of the reversible waveband approach is discussed in detail.Index Terms-Lightpath, reversible waveband, reversible wavelength channel, wavelength-routed networks.