We report the first successful experiment on Point-to-Multipoint (P2MP) VLAN path establishment on the overlay-model-based GMPLS-controlled wide area Ethernet. To support the overlay model, P2MP VLAN path signaling with egress output port indication is proposed and implemented. It is confirmed that our extended RSVP-TE software can correctly establish P2MP VLAN paths in the overlay-model network.

Connection setup on various computer networks is now achieved by GMPLS. This technology is based on the source-routing approach, which requires the source node to store metric information of the entire network prior to computing a route. Thus all metric information must be distributed to all network nodes and kept up-to-date. However, as metric information become more diverse and generalized, it is hard to update all information due to the huge update overhead. Emerging network services and applications require the network to support diverse metrics for achieving various communication qualities. Increasing the number of metrics supported by the network causes excessive processing of metric update messages. To reduce the number of metric update messages, another scheme is required. This paper proposes a connection setup scheme that uses flooding-based signaling rather than the distribution of metric information. The proposed scheme requires only flooding of signaling messages with requested metric information, no routing protocol is required. Evaluations confirm that the proposed scheme achieves connection establishment without excessive overhead. Our analysis shows that the proposed scheme greatly reduces the number of control messages compared to the conventional scheme, while their blocking probabilities are comparable.

As ROADMs (Reconfigurable Optical Add/Drop Multiplexers) are becoming widely used in metro/core networks, distributed control of wavelength paths by extended GMPLS (Generalized MultiProtocol Label Switching) protocols has attracted much attention. For the automatic establishment of an arbitrary wavelength path satisfying dynamic traffic demands over a ROADM or WXC (Wavelength Cross Connect)-based network, precise determination of chromatic dispersion over the path and optimized assignment of dispersion compensation capabilities at related nodes are essential. This paper reports an experiment over in-field fibers where GMPLS-based control was applied for the automatic discovery of chromatic dispersion, path computation, and wavelength path establishment with dynamic adjustment of variable dispersion compensation. The GMPLS-based control scheme, which the authors called GMPLS-Plus, extended GMPLS's distributed control architecture with attributes for automatic discovery, advertisement, and signaling of chromatic dispersion. In this experiment, wavelength paths with distances of 24 km and 360 km were successfully established and error-free data transmission was verified. The experiment also confirmed path restoration with dynamic compensation adjustment upon fiber failure.

Recently, the GMPLS controlled WSON has emerged as a promising optical transport network. In order to guarantee the optical signal transmission feature without deformation, the optoelectronic 3R regenerators still need to be sparsely placed in the network, termed as translucent networks. The growing size and complexity of the translucent network requires a transition of control plane to move from the traditional centralized model to a fully distributed architecture in the future. However, centrally designed routing, wavelength assignment, and 3R regenerator allocation approaches become unfeasible under the distributed paradigm due to the outdated and inconsistent network state information. A common solution is to accelerate the update frequency of network state, but the fundamental problem remains that the inaccurate state information is still inevitable. Furthermore, it adds a significant increase to the control traffic volume which adversely degrades the performance and scalability of the network control system. In order to mitigate the impact of having inaccurate state information on network performance in the distributed systems, a novel RWA approach is proposed in this paper, termed as routing and distributed wavelength assignment with top ranked probing wavelength set computation. In our proposal, the wavelength assignment is performed by signalling process with a set of carefully preselected probing wavelengths. This set is dynamically computed based on the resource utilization each time the network state is refreshed. The PCE module is adopted in WSON control plane to be responsible for the computation of RWA and 3R allocation. The performance of the proposed approach is studied by extensive simulations. The experiment results reveal that by employing the proposed scheme, without loss on the blocking performance the inaccuracy of the wavelength availability information can be well tolerated, and the set-up delay in lightpath provisioning can be kept at a low level.

A translucent wavelength switched optical network (WSON) is a cost-efficient infrastructure between opaque networks and transparent optical networks, which aims at seeking a graceful balance between network cost and service provisioning performance. In this paper, we experimentally present a resilient translucent WSON with the control of an enhanced path computation element (PCE) and extended generalized multi-protocol label switching (GMPLS) controllers. An adaptive routing and wavelength assignment scheme with the consideration of accumulated physical impairments, wavelength availabilities and regenerator allocation is experimentally demonstrated and evaluated for dynamic provisioning of lightpaths. By using two different network scenarios, we experimentally verify the feasibility of the proposed solutions in support of translucent WSON, and quantitatively evaluate the path computation latency, network blocking probability and service disruption time during end-to-end lightpath restoration. We also deeply analyze the experimental results and discuss the synchronization between the PCE and the network status. To the best of our knowledge, the most significant progress and contribution of this paper is that, for the first time, all the proposed methodologies in support of PCE/GMPLS controlled translucent WSON, including protocol extensions and related algorithms, are implemented in a network testbed and experimentally evaluated in detail, which allows verifying their feasibility and effectiveness when being potentially deployed into real translucent WSON.

We propose a mechanism called “optical plug and play” for constructing GMPLS networks automatically. It offers lower operation effort and fast network construction, and avoids misconfiguration. Optical plug and play architecture has its procedure, a link-up search mechanism for OXCs, network and node architectures to realize optical plug and play, and an LMP extension to exchange the information between nodes necessary for identifying adjacent nodes. We implement prototypes of both OXCs and routers that support the optical plug and play proposal. Simulations and experiments confirm its performance and feasibility.

The first global interoperability experiment of GMPLS controlled Ethernet with VLAN tag swapping between two different implementations is successfully demonstrated. High definition video streaming is realized through a newly established Layer 2 Label Switched Path (L2-LSP). The results of this experiment can be applied to designing reliable Layer 2 networks.

A multi-domain GMPLS layer-2 switch capable network with VLAN tag swapping is demonstrated for the first time. In this demonstration, we verify three new features, establishing path with designating VLAN IDs, swapping VLAN ID on prototype switch, and management of VLAN IDs per domain. Using those three features, carrier-class Ethernet backbone networks which supports path route designation in multi-domain network can be established.

Bolstering survivable backbone networks against multiple failures is becoming a common concern among telecom companies that need to continue services even when disasters occur. This paper presents a multiple-failure recovery scheme that considers the operation and management of optical paths. The presented scheme employs scheme escalation from pre-planned restoration to full rerouting. First, the survivability of this scheme against multiple failures is evaluated considering operational constraints such as route selection, resource allocation, and the recovery order of failed paths. The evaluation results show that scheme escalation provides a high level of survivability even under operational constraints, and this paper quantitatively clarifies the impact of these various operational constraints. In addition, the fundamental functions of the scheme escalation are implemented in the Generalized Multi-Protocol Label Switching control plane and verified in an optical-cross-connect-based network.

This paper proposes the Path Computation Element (PCE)-based backbone network architecture and verifies its feasibility through implementation and experiments. PCE communication Protocol (PCEP) is implemented for communication between the PCE and the management system to control and manage Generalized Multi-Protocol Label Switching (GMPLS)-based backbone networks.

In the Next-Generation Network (NGN), accommodating a wide variety of customer networks through virtual private network (VPN) technologies is one of the key issues. In particular, a core network provider has to provide bandwidth-assured and secured data transmission for individual private networks while performing optimal and flexible path selection. We present hierarchically distributed path computation elements (HDPCEs) that enable a virtual private network (VPN) provider to guarantee end-to-end required bandwidth and to maintain the secrecy of the link-state information of each customer from other customers. In previous studies, a VPN provider only considered link states in the provider network and did not consider customer domains connected by the provider network. HDPCEs, which are distributed to customer domains, communicate with an HDPCE for the provider network, and these HDPCEs enable the guarantee of necessary bandwidth for a data transmission from one customer domain to another via a provider network. We propose a new path-selection algorithm in each HDPCE and cooperation scheme to interwork HDPCEs, which are suitable for VPN requirements. In the evaluation, the superiority of HDPCE-based VPN path selection over legacy OSPF-TE-based VPN path selection is demonstrated in two typical VPN models: the dedicated model and shared model.

In this paper the current trends in the optical networking including the physical components, technologies and control architectures are discussed. The possible interaction schemes and implementation models of the automatic communication between applications and network as well as between ASON/GMPLS based network domains are proposed. Finally, the related research activities based on simulation results of control plane dimensioning are illustrated and real test bed experiments on OIF worldwide interoperability demonstration and the ongoing European IST project MUPBED are disseminated.

Implementing the fast-responding multi-layer service network (MLSN) functionality will allow the IP/MPLS service network logical topology and Optical Virtual Network topology to be reconfigured dynamically according to the traffic pattern on the network. Direct links can be created or removed in the logical IP/MPLS service network topology, when either extra capacity in MLSN core is needed or existing capacity in core is no longer required. Reconfiguring the logical and virtual network topologies constitute a new manner by which Traffic Engineering (TE) can solve or avoid network congestion problems and service degradations. As both IP and optical network layers are involved, this is called Multi-layer Traffic Engineering. We proposed border model based MLSN architecture in [5]. In this paper, we define the realization of Multi-Layer TE functions using Path Computation Element (PCE) for Border model based MLSN. It defines nodal requirements for multi-layer TE. Requirements of communication protocol between PCC (Path Computation Client) and PCE is introduced. It presents Virtual Network Topology (VNT) scenarios and steps involved along with examples for PCE-based VNT reconfiguration triggered by network failure, where VNT is a set of different layer's network resource accumulation.

Generalized Multi-protocol Label Switching (GMPLS) technologies are expected a key technology that creates high-performance Internet backbone networks. There were many GMPLS interoperability trials. However, most of them reported the successful results only. How to set up a trial network and how to test it was generally not discussed. In this paper, as a kind of tutorial, detailed GMPLS field trials in the National Institute of Information and Communications Technology (NICT) Kei-han-na Info-Communication Open Laboratory, Interoperability Working Group (WG) are reported. The interoperability WG is aiming at the leading edge GMPLS protocol based Inter-Carrier Interface that utilizes wide-bandwidth, cost-effective photonic technology to implement IP-centric managed networks. The interoperability WG is a consortium for researching the GMPLS protocol and advancing a de facto standard in this area. Its experimental results, new ideas, and protocols are submitted to standardization bodies such as the International Telecommunications Union-Telecommunication standardization sector (ITU-T), the Internet Engineering Task Force (IETF), and the Optical Internetworking Forum (OIF). This paper introduces the activities of the interoperability WG; they include a nationwide GMPLS field trial using the JGN II network with multi-vendor, multi-switching-capable equipment and a GMPLS multi routing area trial that used a multi-vendor lambda-switching-capable network.

The objective of this paper is to survey the Generalized Multi-Protocol Label Switching (GMPLS) based recovery technology for optical transport networks. This paper introduces standardization activities of the GMPLS based recovery technology in the Internet Engineering Task Force (IETF), and recent progress of related experiments. In addition, this paper extracts requirements for the GMPLS based recovery technology through the evaluation of existing network elements, which can be client nodes of the optical transport networks. The results of field evaluations on the GMPLS based recovery technology are also introduced in this paper. Then, this paper addresses the issues for future deployment of the GMPLS based recovery technology for the optical transport networks.

This paper presents the latest trends in Generalized Multi-Protocol Label Switching (GMPLS) standardization within the Internet Engineering Task Force (IETF). GMPLS, a suite of control and management plane protocols, represents an extension of MPLS to cover any connection-oriented technology, such as packet (or MPLS), Time Division Multiplexing (TDM), lambda and fiber. GMPLS allows automated network operations, distributed at the network equipment level, with multi-vendor and multi-layer interoperability. As such, it is expected that GMPLS will enable control and management of the transport network by standardized mechanisms, rather than proprietary management systems and interfaces. In addition, GMPLS offers opportunities to integrate control and management of multiple network layers. The basic suite of GMPLS protocols, namely signaling, routing and link management, has been already standardized, and has been shown to be stable and functional through several years of testing and early deployments. Now carriers are looking at how they can leverage the protocols to realize revenue and activate advanced services. Accordingly, discussion in the IETF has shifted to how to apply GMPLS protocols to support various scenarios and use cases. After briefly reviewing GMPLS basics, this paper presents the latest trends in GMPLS standardization, with a focus on deployment strategies, service aspects, and operation and management.

An integration of the access/backbone network is expected to become indispensable in the future. We analyze the current and future optical networks and we describe the promising technologies. GMPLS architecture in backbone networks and WDM PON architecture in access networks will play the most important roles. We overview recent studies on the access/backbone integrated network to achieve guaranteed QoS. We also describe the developed system architecture as a milestone toward the access/backbone integrated network.

We survey traffic matrix models, whose elements represent the traffic demand between source-destination pair nodes. Modeling the traffic matrix is useful for multilayer Traffic Engineering (TE) in IP optical networks. Multilayer TE techniques make the network so designed flexible and reliable. This is because it allows reconfiguration of the virtual network topology (VNT), which consists of a set of several lower-layer (optical) paths and is provided to the higher layer, in response to fluctuations (diurnal) in traffic demand. It is, therefore, important to synthetically generate traffic matrices as close to the real ones as possible to maximize the performance of multilayer TE. We compare several models and clarify their applicability to VNT design and control. We find that it is difficult in practice to make an accurate traffic matrix with conventional schemes because of the high cost for data measurement and the complicated calculations involved. To overcome these problems, we newly introduce a simplified traffic matrix model that is practical; it well mirrors real networks. Next, this paper presents our developed server, the IP Optical TE server. It performs multilayer TE in IP optical networks. We evaluate the effectiveness of multilayer TE using our developed IP Optical server and the simplified traffic matrix. We confirm that multilayer TE offers significant CAPEX savings. Similarly, we demonstrate basic traffic control in IP optical networks, and confirm the dynamic control of the network and the feasibility of the IP Optical TE server.

This paper proposes an advanced hybrid network architecture and a comprehensive network design of the next-generation science information network, called SINET3. Effectively combining layer-1 switches and IP/MPLS routers, the network provides layer-1 end-to-end circuit services as well as IP and Ethernet services and enables flexible resource allocation in response to service demands. The detailed network design focuses on the tangible achievement of providing a wide range of network services, such as multiple layer services, multiple virtual private network services, advanced qualities of service, and layer-1 bandwidth on demand services. It also covers high-availability capabilities and effective resource assignment in the hybrid network. The cost reduction effect of our network architecture is also shown in this paper.

Recently, integration of multiple network domains, such as optical fiber domains and packet domains, has been required by network providers and users. To achieve this interdomain integration, generalized multiprotocol label switching (GMPLS) is now receiving more attention. One of the main features of a GMPLS network is its multilayered complexity, which sometimes places a large burden on source GMPLS routers to determine optimal routes to destinations in other domains and causes label switching path (LSP)-setup delays. To reduce this source-router burden, we propose hierarchically distributed path computation equipment (HDPCE) that cooperates with each other to determine interdomain routes, reduce setup delay, and conduct flexible interdomain route creation taking individual GMPLS domain routing policies into consideration. Each domain routing policy can be set independently from that of other domains, and this routing information is not revealed to other peer domains because each HDPCE is allocated to every domain, including an interdomain, which has several underlying domains under it. Each underlying domain's HDPCE flexibly chooses three types of routing policies depending on the domain's requirement, and the interdomain HDPCE conducts interdomain route creation in accordance with underlying domain policies. OSPF routing protocol is now being applied to interdomain routing on GMPLS networks. Therefore, we compare the proposed HDPCE-based interdomain route creation with OSPF-based route creation in terms of performance and applicability, and we evaluate the effects of each underlying domain policy on interdomain route creation.