Proc. SPIE. 6388, Optical Transmission Systems and Equipment for Networking V
KEYWORDS: Switches, Switching, Green fluorescent protein, Video, Interfaces, Time division multiplexing, Local area networks, Dense wavelength division multiplexing, Network architectures, Standards development
In today's converged network environment, a rapid transition to unified packet-based core/edge network architecture is occurring. Core architecture becomes a two-layer network structure based on IP/MPLS (Internet Protocol/Multi-Protocol Label Switch) transport over DWDM bandwidth pipes, which is the most effective way of providing sharing network capacities, enabling efficient protection schemes, and delivering guaranteed end-to-end performance. The edge network is recognized as a place for an intense manipulation of both data streams and services, through traffic grooming, exchange, and service convergence. Three major groups of the end-to-end services are voice, data, and video. Today's reality is that current network structure is in transitional phase, where a number of legacy services, delivering voice and data, are still in place, while packet based services are being rapidly introduced. Optical ROADM handles the wavelength bandwidth pipes and provides flexible handling of wavelength paths (amplification, add/drop, and wavelength switching). In-service upgrade should be achievable at any particular location, which means that in line-amplifier site can be converted to ROADM site. In addition, the ROADM site should be upgradeable to full wavelength crossconnect functionality, which is required in a number of application scenarios. The ROADM functionality is not limited to wavelength related functions, but rather handles the key functions related to multiservice environment by accommodating Layer 1&2 features from a blade. Herewith, we will analyze the role of ROADM, its functions, and expansion over cross-layer applications, and present a structure that is the most appropriate to multiservice packetized environment.
A testbed for metro wavelength division multiplexing (WDM) network is realized and tested. The testbed contains a reconfigurable optical add/drop multiplexer (ROADM) node, a 2x2 wavelength cross-connect (WXC) node, and two interconnected two-fiber bidirectional path protected switching ring networks (TF-BPSR). Both the ROADM and WXC node are bidirectional nodes, so they can select channels from the working and the protection ring networks simultaneously, and they support both protected and unprotected services. The ROADM node uses a flexible band tunable filter (FBTF) to drop a waveband from the input WDM signals and send the express channels directly to the output port. As a result, the physical impairment accumulated on the express channels can be minimized. It also has a modular structure, so additional modules can be cascaded to expand the capacity and functionality of the node without any interruption to current services. The WXC node is realized with interconnected ROADM modules that are comprised of wavelength selective switches (WSSes). Arbitrary wavelength or wavelength sets can be either dropped in the node or cross-connected in a non-blocking manner. Multiple services, such as OC-48 and OC-192 SONET signals, gigabit Ethernet streams carrying interactive movie signals, and live video broadcasting services, are carried in the network, dropped in the ROADM and WXC node, and switched between the two ring networks. The testbed is controlled by a websever based network management system that facilitates remote control and monitoring. Experiments demonstrate that the performance of the nodes and the testbed meets the requirement of the services.
An overview of options and solutions related to broadband access by using optical fiber as a main transmission medium has been presented. The most promising approaches associated with next generation optical fiber-based access networks have been outlined.
Conference Committee Involvement (1)
Optical Transmission Systems and Equipment for Networking V
2 October 2006 | Boston, Massachusetts, United States