Measurement-based reconfiguration in optical ring metro networks

Abstract

Abstract-Single-hop wavelength division multiplexing (WDM) optical ring networks operating in packet mode are one of the most promising architectures for the design of innovative metropolitan network (metro) architectures. They permit a cost-effective design, with a good combination of optical and electronic technologies, while supporting features like restoration and reconfiguration that are essential in any metro scenario. In this article, we address the tunability requirements that lead to an effective resource usage and permit reconfiguration in optical WDM metros. We introduce reconfiguration algorithms that, on the basis of traffic measurements, adapt the network configuration to traffic demands to optimize performance. Using a specific network architecture as a reference case, the paper aims at the broader goal of showing which are the advantages fostered by innovative network designs exploiting the features of optical technologies.Index Terms-All-optical networks, dynamic network configuration, logical topology design, wavelength division multiplexing (WDM) packet rings.

Dynamic Wavelength Allocation in IP/WDM Metro Access Networks

“…Similar dynamic reconfiguration issues also arise in a single hop WDM packet ring, which is another promising architecture for future metro networks [25,58].…”

“…A similar problem is considered in [58], where the reconfiguration algorithm relies on measurements to detect the traffic pattern which is assumed to be unknown. The optimum way of reconfiguring receivers and deciding on whether to schedule the reconfiguration actions are again discussed as decoupled problems.…”

“…First, the number of channels is assumed to be larger than the number of nodes and one or more separate wavelength channels are assigned to each node. The problems of "How to reconfigure" and "When to reconfigure" are jointly handled to produce solutions which aim to gradually improve the load balance in the network by making single wavelength switches at each decision instant in contrast to [25,58] where the reconfiguration actions result in multiple switches to take the network into the most balanced state possible. The cost of reconfiguration is modeled as loss of capacity during the reconfiguration delay, where it is calculated based on a pre-defined function using the number of retunings as a parameter in [25], and not considered explicitly in [58].…”

FiWi Access Networks Based on Next-Generation PON and Gigabit-Class WLAN Technologies: A Capacity and Delay Analysis

“…After the initialization step to minimum hop routes, the second step of OFRA computes for each source-destination node pair the path with the minimization objective (42) where represents the long-run traffic intensity at a generic FiWi network node , which may be either an optical node belonging to the fiber backhaul or a wireless node belonging to the wireless mesh front end. Based on a combination of historic traffic patterns as well as traffic measurements and estimations similar to [51]- [53], the traffic intensities used in OFRA can be periodically updated with strategies similar to [9] and [54]. These long-run traffic intensities vary typically slowly, e.g., with a diurnal pattern, allowing essentially offline computation of the OFRA paths.…”

WONDER: Overview of a Packet-Switched MAN Architecture

“…When another node has a packet to send to node i it must tune its transmitter to λi in order to reach it. The optical filter selecting the received wavelength can be fixed or (slowly) tunable; in this latter case the received wavelength can be dynamically reconfigured thus increasing the flexibility in the allocation of traffic between nodes [3] to the available channels. …”