optical multi-service core and access networks

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SERIES EDITORIAL

OPTICAL MULTI-SERVICE CORE AND ACCESS NETWORKS

Osman S. Gebizlioglu

T

he global optical communications industry has continued to show progress in all segments from access to core networks through 2014. The two most notable trends of 2013 have been expanding in 2014: 1) the emergence of the packet optical transport system (P-OTS) concept with the service provider goal to build a common network infrastructure by integrating Ethernet, IP/multiprotocol label switching (MPLS), and dense wavelengthdivision multiplexing (DWDM); 2) intensifying focus and attention on network functions virtualization (NFV) and software-defined networking (SDN) to provide service providers with the tools for more effective operation and management of optical communications networks. Some global service providers have been establishing and announcing their target timeframes for transitioning to all-IP network operations, while major industry standards organizations and fora have been working to publish their guidelines and frameworks for NFV and SDN. These important trends are expected to gain additional momentum through the rest of 2014 as the industry continues to develop to meet the growing global communications needs. In this issue, we have selected two contributions that address the performance of multi-service WDM/optical code-division multiplexing (OCDM) core networks and network sharing scheme along with its cost implications in passive optical networks. In the first contribution, “Application of Optical Multilevel Transmission Technique in WDM/OCDM-Based Core Networks,” H. Beyranvand and J. A. Salehi propose a new scheme to improve the performance of multi-service WDM/OCDM-based core networks. Their proposal is based on utilizing the optical multilevel transmission technique (MLTT) to mitigate the multiple access interference (MAI) effect of OCDM. In this multilevel-multiclass network, users of each class are divided into multiple groups, and users of each group are allowed to transmit at a spe-

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Vijay Jain

cific power level. The authors demonstrate that the proposed multilevel-multiservice scheme outperforms previously introduced multiservice WDM/OCDM-based networks by reducing interference with MLTT. The proposed scheme involves a modification implemented at the data plane by upgrading the intermediate optical routers to support MLTT. In the proposed network model, the data and control planes are separated and can be designed independently. However, the authors note that a dataplane-aware control approach, which recognizes the information of the data plane, outperforms a data-planeunaware algorithm with regard to average error probability. In the second contribution, “Cost Analysis of Network Sharing in FTTH/PONs,” J. R. Schneir and Y. Xiong present the cost implications of a network sharing scheme for different fiber-to-the-home/passive optical network (FTTH/PON) architectures. They address the high cost of passive infrastructure and the civil works. One approach with which operators could reduce the amount of investment required to deploy fiber access networks would be to share the network infrastructure, thereby reducing the investment needed to deploy and operate the FTTH network. The authors use various metrics to understand the effect of a network sharing arrangement on costs. The results show that for the majority of cases studied, the cost per home connected and the payback period increase when employing a network sharing scheme, but the initial investment is significantly reduced. The reuse of existing passive infrastructure does not bring any cost advantage in comparison to the standalone scenario; however, it helps reduce the total cost per home connected. In this second Optical Communications Series (OCS) issue of 2014, we thank all authors and reviewers for their contributions to the OCS and invite your submissions on all aspects of optical communications technologies.

IEEE Communications Magazine • August 2014