Dynamic service provisioning in space-division multiplexing elastic optical networks

Abstract

In space-division multiplexing elastic optical networks (SDM-EONs) based on multicore fibers, the problem of finding a lightpath for a new connection request involves routing, modulation, spectrum, and core assignment (RMSCA). A lightpath can be constructed using contiguous free frequency slot (FS) blocks with different frequency slot allocation patterns (FSAPs), where each FSAP can incur different amounts of wasted FSs. Aiming at using the FSAP with the least amount of wasted FSs and exploiting path diversity, a set of new algorithms are proposed to solve the RMSCA problem. Before any connection requests arrive, all candidate paths between each pair of nodes and all FSAPs for each possible bandwidth requirement are identified and sorted. When a connection request arrives, two approaches can be used to establish a lightpath: the path-first or spectrum-first approach. We show that by packing lightpaths toward FSs with the smallest FS indexes, the spectrum-first approach leaves bigger contiguous FS blocks for future requests. As a result, the request blocking probability is minimized.

LBFA: A Load-Balanced and Fragmentation-Aware Resource Allocation Algorithm in Space-Division Multiplexing Elastic Optical Networks

“…LBFA is realized by finding the least loaded path to carry the request, and selecting the best SCA to minimize spectral and spatial fragmentation. Simulation results show that, compared with the benchmark algorithm proposed in [5], our LBFA algorithm can achieve tremendous improvement in RBP and spectral efficiency in SDM-EONs.…”

“…However, considering the large variety of the requirements for interconnections between data centers [3,4], it is inefficient to utilize a conventional fixed-grid WDM optical network to support these advanced network infrastructures. Thus, space-division multiplexing elastic optical networks (SDM-EONs) [5] were proposed as a promising solution for future optical networks. SDM-EONs utilize both space division multiplexing (SDM) [6] and elastic optical network (EON) [7] technologies.…”

“…SDM-EONs can be achieved by using (i) multiple modes in a multimode fiber, (ii) multiple cores in a multicore fiber (MCF), or (iii) both modes and cores in a few-mode multicore fiber (FM-MCF). Due to fine spatial switching granularity and similar attenuation properties as those of the single-core fiber [6], the weakly coupled MCF was widely adopted in the studies of SDM-EONs [5,13,14]. Benefitting from joint processing, amplifying, and switching, superchannels (SChs) that comprise a set of contiguous FSs on multiple cores can be realized in MCF [9,15].…”

“…The intercore crosstalk, which is generally inversely proportional to the core pitch, can be compensated using multi-input-multioutput (MIMO) at the cost of increased receiver complexity and energy consumption [16]. The problem of allocating resources to the SCh involves routing, modulation, spectrum, and core assignment (RMSCA) [5,13,14], and many algorithms have been designed to solve this problem. Typically, these solutions consist of four parts: (i) finding a route between source and destination nodes, (ii) selecting a modulation format according to the distance of the route, (iii) choosing the core(s) along the route to carry the optical channel, and (iv) allocating enough adjacent FSs to meet the bandwidth requirement.…”

“…The simplest approach to assign the route and the modulation format to an SCh is to use the predetermined shortest paths [5,16]. However, the shortest-path algorithm finds all routes with the lowest bandwidth consumption while ignoring the distribution of traffic load.…”