“…Numerous interconnection networks have been proposed over the last fifty years or so and new designs continue to emerge. There are various reasons for this ongoing investigation and these include the following: the changing face of parallel and distributed systems, which encompass networks-on-chips, supercomputers, clusters and data centre networks, along with new and unforeseen applications, imposes new demands on the underlying interconnection networks (see, e.g., [14]); interconnection networks also feature in peer-to-peer and overlay networks (see, e.g., [15]), social networks (see, e.g., [16]) and wireless sensor networks (see, e.g., [2]); and the 'structured' graphs into which interconnection networks sit feature in combinatorial chemistry (see, e.g., [1]), coding theory (see, e.g., [3]), mathematical physics (see, e.g., [12]) and discrete mathematics in general (often purely as interesting combinatorial objects as regards the latter instantiation; see, e.g., [6,8,18]).…”