Availability-Aware Routing for Large-Scale Hybrid Wireless-Optical Broadband Access Network

Abstract

In large-scale hybrid wireless-optical broadband access networks, the availability of wireless links and optical links varies considerably. Availability-aware routing can significantly improve availability and throughput by encouraging more usage of PON.

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

“…For Poisson frame traffic, the downstream queueing delay is thus modeled by an M/G/1 queue characterized by the Pollaczek-Khintchine formula [46] (8) giving the total downstream frame delay (9) Weighing the downstream delays in the sectors by the relative downstream traffic intensities in the sectors, gives the average downstream delay of the wavelengthrouting multistage WDM PON (10) For the upstream delay, we model each wavelength channel , as a single upstream wavelength channel of a conventional EPON. Accordingly, from (39) in [47], we obtain for the mean upstream delay of sector (11) and the average upstream delay of the wavelength-routing multistage WDM PON equals (12) To improve the accuracy of our delay analysis, we take into account that traffic coming from an ONU in sector and destined to ONU in sector is queued at the intermediate OLT before being sent downstream to ONU , i.e., the OLT acts like an insertion buffer between ONUs and . Consequently, to compensate for the queueing delay at the OLT we subtract the correction term proposed in [48] (13) whereby for the setting that for all channels (14) denotes the rate of upstream traffic in sector destined for sector , from the above calculated mean downstream delay.…”

“…Important examples of wireless routing algorithms for FiWi access networks are the so-called delay-aware routing algorithm (DARA) [7], delay-differentiated routing algorithm (DDRA) [8], capacity-and-delay-aware routing (CaDAR) [9], and risk-and-delay-aware routing (RADAR) algorithm [10]. Recently proposed integrated routing algorithms for path computation across the optical-wireless interface include the so-called availability-aware routing [11], multipath routing [12], and energy-aware routing algorithms [13]. Most of these previous studies formulated routing in FiWi access networks as an optimization problem and obtained results mainly by means of simulation.…”

Dependable Fiber-Wireless (FiWi) Access Networks and Their Role in a Sustainable Third Industrial Revolution Economy

“…By capitalizing on the aforementioned fiber fault detection, localization, and partial optical protection techniques, NG-PONs can be designed to meet high levels of availability. It is well understood that consequently the availability of optical links and wireless links differ significantly from each other; and that availability-aware routing should be applied not only to meet the specified availability, an important parameter in many service level agreements (SLAs) between network operator and subscribers, but also to increase the overall availability and survivability of FiWi access networks by making more use of monitored and protected NG-PONs [24]. While NG-PONs are able to provide high availability and survivability levels, the performance of wireless links depends on a variety of external parameters, which in many cases can be only modelled statistically [25].…”

Analytical framework for the capacity and delay evaluation of next-generation FiWi network routing algorithms

“…In particular, the design of routing algorithms for such legacy EPON/WLANmesh based FiWi networks received a great deal of attention, resulting in a large number of proposed wireless (e.g., DARA [3]), integrated optical-wireless (e.g., availability-aware routing [4]), multipath (e.g., [5]), and energy-aware routing algorithms (e.g., [6]). Most of these previous studies formulated routing in FiWi networks as an optimization problem and obtained results mainly by means of simulation.…”