The emerging software defined networking (SDN) paradigm separates the data plane from the control plane and centralizes network control in an SDN controller. Applications interact with controllers to implement network services, such as network transport with quality of service. SDN facilitates the virtualization of network functions so that multiple virtual networks can operate over a given installed physical network infrastructure. Due to the specific characteristics of optical (photonic) communication components and the high optical transmission capacities, SDN-based optical networking poses particular challenges, but holds also great potential. In this article, we comprehensively survey studies that examine the SDN paradigm in optical networks; in brief, we survey the area of software defined optical networks (SDONs). We mainly organize the SDON studies into studies focused on the infrastructure layer, the control layer, and the application layer. Moreover, we cover SDON studies focused on network virtualization, as well as SDON studies focused on the orchestration of multilayer and multidomain networking. Based on the survey, we identify open challenges for SDONs and outline future directions.

Software Defined Optical Networks (SDONs): A Comprehensive Survey

The present invention generally relates to communication and controlled sharing of digital content among networked users, and is more particularly concerned with creation of an improved sharing network for relaying data among linked nodal members of a social network. An ad hoc network may be a hybrid P2P network that conforms to a virtual peer representation accessible as a single node from outside the given social network nodes. Members of a pre-existing social network may selectively activate embedded latent peers and link to an aggregation node to form a hybrid P2P network. Content may be shared in a controlled distribution according to level rights among participating network nodes. Playlists and/or specialized user interfaces may also be employed to facilitate content sharing among social network members of a virtual peer.

System and method of sharing content among multiple social network nodes using an aggregation node

A centralized controller provides dynamic end-to-end network path setup across multiple network layers. In particular, the centralized controller manages end-to-end network path setup that provisions a path at both the transport network layer (e.g., optical) and the service network layer (e.g., IP/MPLS). The centralized controller performs path computation for an optical path at the transport network layer and for a path at the service network layer that transports network traffic on the underlying optical transport path, based on information obtained by the centralized controller from the underlying network components at both layers.

Dynamic end-to-end network path setup across multiple network layers

A path control device includes a TE database and a local database for storing topology information showing states of use of links in a network, a topology information collection unit collecting the topology information of the respective communication nodes therefrom and updating the TE database by the topology information, a path solution unit determining a path of the network referring to the local database, an internal update unit recognizing a link included in the determined path and updating a local database by information as to said link, and an update determination unit matching the topology information of both the databases by comparing both the databases.

Network path control system, path control device, and path control method

Resilience-driven restoration model for interdependent infrastructure networks

This article presents two dynamic multilayer routing policies implemented in the photonic MPLS router developed by NTT for IP+optical generalized MPLS networks. According to IP traffic requests, wavelength paths called lambda label switched paths are set up and released in a distributed manner based on GMPLS routing and signaling protocols. Both dynamic routing policies first try to allocate a newly requested electrical path to an existing optical path that directly connects the source and destination nodes. If such a path is not available, the two policies employ different procedures. Policy 1 tries to find available existing optical paths with two or more hops that connect the source and destination nodes. Policy 2 tries to establish a new one-hop optical path between source and destination nodes. The performances of the two routing policies are evaluated. Simulation results suggest that policy 2 outperforms policy 1 if p is large, where p is the number of packet-switching-capable ports; the reverse is true only if p is small. We observe that p is the key factor in choosing the most appropriate routing policy. We also describe items that need to be standardized in the IETF to effectively achieve multilayer traffic engineering.

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Dynamic multilayer routing schemes in GMPLS-based IP+optical networks

An optical network includes links and nodes. In each node, a control section sets an optical path to be used for optical transport. A switching section performs switching of the optical path. In the control section, a link observation section observes the wavelength of signal light that is being transmitted through a link connected to the node as the utilization of the link. A flooding section notifies each of the remaining nodes of the link utilization and acquires a link utilization observed by each of the remaining nodes so as to share the link utilization between the nodes. An optical path calculation section selects the optical path to be used for optical transport by calculation using the link utilization observed by the link observation section and the link utilization observed by each of the remaining nodes. An optical path setting section sets the optical path selected by the optical path calculation section to the optical path to be used for optical transport.

Optical network, optical cross-connect apparatus, photonic-IP network and node

A layered network node of which a network it belongs is divided up into cells which are constituted by a plurality of nodes; the cells are defined as virtual nodes; if links exist which connect the interiors of the virtual nodes and the exterior, contact points between them are defined as interfaces of the virtual nodes; the virtual network constituted by the virtual nodes is further divided up into cells and making them into virtual nodes; said virtual network is defined as a network of a higher level with respect to the initial virtual network; by performing said operation of division into cells and making into virtual nodes once or a plurality of times, the layered network is constituted; path computation is performed from the source node to a destination node in a stepwise manner by dispersing it over the various layers.

Layered network node, network incorporating the same, node, and layered network

Performance of Distributed-Controlled Dynamic Wavelength-Conversion Optical Networks.

A multi-layer photonic network and nodes used therein are provided. The multi-layer photonic network comprises a packet network which performs switching and transfer in packet units, and a photonic network comprising optical transmission lines and photonic switches, and which accommodates the packet network. The multi-layer photonic network also has a two layer structure of optical wavelength links (O-LSPs) and packet links (E-LSPs). The O-LSPs are constituted by the optical transmission lines and comprise optical wavelength switching capability (LSC) which is capable of switching in optical wavelength units and packet switching capability (PSC) which is capable of switching in packet units at both their ends. The E-LSPs include the O-LSPs and PSCs at both their ends. Each node includes a section for automatically establishing an O-LSP according to an establishment request for an E-LSP while taking account of path information including path cost, resource consumption, and traffic quantity.

Daisaku Shimazaki

Papers

Dynamic multilayer routing schemes in GMPLS-based IP+optical networks

Optical network, optical cross-connect apparatus, photonic-IP network and node

Layered network node, network incorporating the same, node, and layered network

Performance of Distributed-Controlled Dynamic Wavelength-Conversion Optical Networks.

Node used in photonic network, and photonic network