Antonis Hadjiantonis

A novel decentralized ethernet-based PON access architecture for provisioning differentiated QoS

To date, the mainstream ethernet passive optical network (EPON) bandwidth allocation schemes as well as the new IEEE 802.3ah Ethernet in the first mile Task Force specifications have been centralized, relying on a component in the central office [optical line termination (OLT)] to provision upstream traffic. Hence, the OLT is the only device that can arbitrate time-division access to the shared channel. Since the OLT has global knowledge of the state of the entire network, this is a centralized control plane in which the OLT has centralized intelligence. This paper proposes novel distributed EPON architectures, and in the process proves that these distributed networking architectures and the associated bandwidth allocation algorithms and protocols have characteristics that make them far better suited for provisioning quality of service (QoS) schemes necessary for properly handling data, voice, video, and other real-time streaming advanced multimedia services over a single line. Specifically, this paper proposes a novel ethernet over star coupler-based PON architecture that uses a fully distributed time-division multiple-access (TDMA) arbitration scheme. Supported by the decentralized scheme, this paper proposes several QoS-based dynamic bandwidth allocation (DBA) algorithms in which the OLT is excluded from the implementation of the time slot assignment. In contrast with the mainstream centralized EPON architectures that combine priority queuing [intra-optical network unit (ONU) scheduling] with DBA schemes (inter-ONU scheduling), the proposed distributed EPON architecture supports differentiated services through the integration of both scheduling mechanisms at the ONU (intra-ONU scheduling). The introduction of this integration feature that can only be supported by a decentralized architecture provides better QoS guarantees. Furthermore, in addition to the added flexibility and reliability, the overall performance of the proposed decentralized EPON architecture and the associated bandwidth allocation algorithms are shown to be at least as efficient as their centralized counterparts.

Dynamic provisioning of low-speed unicast/multicast traffic demands in mesh-based WDM optical networks

This paper addresses the problem of dynamically provisioning both low-speed unicast and multicast connection requests in mesh-based wavelength division multiplexing (WDM) optical networks. Several routing/provisioning schemes to dynamically provision both unicast and multicast connection requests are presented. In addition, a constraint-based grooming strategy is devised to utilize the overall network resources as efficiently as possible. Based on this strategy, several different sequential multicast grooming heuristics are first presented. Then, we devise a hybrid grooming approach and combine it with sequential approaches to achieve a grooming scheme that is biased toward serving multicast traffic demands in comparison with all other sequential grooming approaches. To achieve our objective, we decompose the problem into four subproblems: 1) routing problem; 2) light-tree-based logical-topology-design problem; 3) provisioning problem; and 4) traffic-grooming problem. The simulation results of the proposed schemes are compared with each other and with those of conventional nongrooming approaches. To the best of our knowledge, this is the first detailed paper to address and examine the problem of grooming dynamic multicast traffic demands.

Sequential and hybrid grooming approaches for multicast traffic in WDM networks

The problem of traffic grooming is a crucial constituent in designing WDM networks and has been extensively studied in the literature. Although it is expected that a part of the future traffic of WDM networks will be multicast, most studies of traffic grooming have assumed only unicast traffic. The paper investigates the problem of grooming multicast traffic in WDM networks. More specifically, different sequential single-hop and multi-hop grooming approaches are studied and compared to traditional non-grooming approaches. We also propose a hybrid approach that utilizes the combined resources at the logical and optical layers.

Dynamic Provisioning of Survivable Heterogeneous Multicast and Unicast Traffic in WDM Networks

The problem of protecting purely multicast connections in WDM mesh network has recently started to receive some attention in the literature. In fact, WDM traffic is heterogeneous in nature and only part of the traffic is multicast and the rest is unicast, therefore we expect the presence of both unicast and multicast traffic in future optical networks. This paper studies the problem of dynamic provisioning of survivable heterogeneous unicast and multicast traffic in WDM networks. Specifically, we propose new protection schemes to provision and protect unicast and multicast connection requests against singlelink failures in WDM-mesh networks. The simulation results of the proposed protection schemes are compared with each others and with those found in the literature. The results showed that our proposed scheme TP-OSPT outperforms all other schemes for moderate and large multicast group size. On the other hand, our proposed scheme OCR performs the best for small multicast group size.

Evolution to a Converged Layer 1, 2 in a Global-Scale, Native Ethernet Over WDM-Based Optical Networking Architecture

There is an emerging wide interest to transition from legacy WAN transport technologies to Ethernet-based technology. The current round of carrier Ethernet standards will successfully equip service providers (SPs) with the required tools to provide carrier-grade scalability and to provision and engineer connection-oriented point-to-point (P2P) packet trunks across a native Ethernet infrastructure. Building on these standards, this paper demonstrates how to support and implement full traffic engineering in a global-scale, two-tiered native Ethernet-over-WDM optical networking architecture. To achieve these objectives, several networking innovations are presented and developed including: 1) a GMPLS-based unified control plane that offers a tighter integration between layer-1 (optical transport layer) and layer-2 (Ethernet layer), 2) a fully distributed integrated routing and signaling framework for dynamically provisioning Ethernet switched paths (ESPs) at any bandwidth granularity including both full wavelength and finer granularity (sub-lambda) ESPs in an integrated Ethernet-optical networking environment, and 3) a novel notion of an integrated link-state advertisements strategy that is consistent with a fully integrated routing and signaling protocol

Multicast traffic grooming in WDM networks

We investigate the problem of grooming dynamic multicast traffic in WDM mesh networks. This problem is equivalent to designing a light-tree based logical topology for multicast streams. It consists of four subproblems, namely routing, wavelength assignment, design of a light-tree based logical topology, and traffic-grooming. We develop different routing schemes to efficiently groom low-speed connections on the light-tree based logical topology. Numerical results demonstrate that the proposed approaches use the network resources more efficiently compared to the nongrooming approach and the approach of serving the multicast requests as separate unicast requests. Moreover, amongst the proposed techniques, the logical-first multihop grooming scheme MC-MHl outperforms all other schemes in terms of blocking probability and performance gain.

A Novel Ring-Based WDM-PON Access Architecture for the Efficient Utilization of Network Resources

This work proposes a simple and cost effective local access WDM-PON architecture that combines the salient features of both traditional static WDM-PON (i.e., dedicated connectivity to all subscribers with bit rate and protocol transparencies, guaranteed QoS, and increased security) and dynamic WDM-PON (i.e., efficiently utilizing network resources via dynamic wavelength allocation/sharing among end-users). Specifically, this paper proposes and devises a novel ring-based local access WDM-PON architecture that efficiently supports dynamic allocation of wavelengths/timeslots and sharing traffic as well as a truly shared LAN capability among PON end-users.

A novel IP-over-optical network interconnection model for the next-generation optical Internet

The paper proposes a novel IP-over-optical network interconnection model that takes the best features from both the overlay and peer models while avoiding their limitations. Specifically, the proposed model utilizes an optical layer-based unified control plane that manages both routers and optical switches (analogous to the peer model), while still retaining complete separation between the optical and IP layers of the overlay model. This is achieved by shifting the control plane functionalities previously associated with the IP layer to the IP/MPLS-aware, non-traffic bearing OXC controller modules located within the optical domain. In this architecture, better decisions can be made for provisioning and managing network resources, leading to their more efficient use. Based on the proposed model, an integrated dynamic routing algorithm, that takes into account the combined topology and resource usage information at both the IP and optical layers, is developed.

On the Merits of Migrating From Legacy Circuit-Switched Cellular Infrastructure to a Fully Packet-Based RAN Architecture

This paper addresses the important issue of how to optimize the performance of the current mobile backhaul Radio Access Network (RAN) infrastructure to cope with the growing and dynamic nature of the emerging data-centric mobile multimedia traffic and services. Specifically, this work proposes and devises a simple and cost-effective EPON-based dynamic multiservice RAN architecture that efficiently transports and supports a wide range of existing and emerging data-centric mobile multimedia traffic and services along with the diverse quality of service (QoS) and rate requirements set by these services. To conform to the emerging Fourth-Generation (4G) Long-Term Evolution (LTE) standards, the proposed centralized packet-based RAN architecture is further evolved to a distributed architecture. The performance of the distributed packet-based RAN architecture is then examined and compared with that of the centralized one. In general, the simulation results indicate that packet-based RAN architectures are far better suited for coping with the dynamic and bursty traffic pattern of the emerging data-centric mobile multimedia services along with the diverse QoS and rate requirements set by these services.

Transportation and switching of native ethernet frames across MPLS/GMPLS managed and controlled optical data networks

In this talk, we outline and propose simple optical networking solutions that constitute a credible starting foundation en-route to the rapid adoption and deployment of fully automated optical data networking paradigms.