K. Shrikhande

SUCCESS: a next-generation hybrid WDM/TDM optical access network architecture

In this paper, the authors propose a next-generation hybrid WDM/TDM optical access network architecture called Stanford University aCCESS or SUCCESS. This architecture provides practical migration steps from current-generation time-division multiplexing (TDM)-passive optical network (PONs) to future WDM optical access networks. The architecture is backward compatible for users on existing TDM-PONs, while simultaneously capable of providing upgraded high-bandwidth services to new users on DWDM-PONs through advanced WDM techniques. The SUCCESS architecture is based on a collector ring and several distribution stars connecting the CO and the users. A semipassive configuration of the Remote Nodes (RNs) enables protection and restoration, making the network resilient to power failures. A novel design of the OLT and DWDM-PON ONUs minimizes the system cost considerably: 1) tunable lasers and receivers at the OLT are shared by all ONUs on the network to reduce the transceiver count and 2) the fast tunable lasers not only generate downstream data traffic but also provide DWDM-PON ONUs with optical CW bursts for their upstream data transmission. Results from an experimental system testbed support the feasibility of the proposed SUCCESS architecture. Also, simulation results of the first SUCCESS DWDM-PON MAC protocol verify that it can efficiently provide bidirectional transmission between the OLT and ONUs over multiple wavelengths with a small number of tunable transmitters and receivers.

A summary of the HORNET project: a next-generation metropolitan area network

Metropolitan area networks are currently undergoing an evolution aimed at more efficiently transport of data-oriented traffic. However, the incoming generation of metro networks is based on conventional technology, which prevents them scaling cost-effectively to ultrahigh capacities. We have developed a new architecture and set of protocols for the next generation of metro networks. The architecture, named HORNET (hybrid optoelectronic ring network), is a packet-over-wavelength-division multiplexing ring network that utilizes fast-tunable packet transmitters and wavelength routing to enable it to scale cost-effectively to ultrahigh capacities. A control-channel-based media access control (MAC) protocol enables the network nodes to share the bandwidth of the network while preventing collisions. The MAC protocol is designed to transport variable-sized packets and to provide fairness control to all network end users. The efficiency and the fairness of the MAC protocol is demonstrated with custom-designed simulations. The implementation of the MAC protocol and the survivability of the network have been demonstrated in a laboratory experimental testbed. The article summarizes the accomplishments of the HORNET project, including the design, analysis, and demonstration of a metro architecture and a set of protocols. The HORNET architecture is an excellent candidate for next-generation high-capacity metro networks.

HORNET: a packet-over-WDM multiple access metropolitan area ring network

Current metropolitan area networks (MANs) based on the SONET transport are not developing at the rate required to support the phenomenal increase in data traffic. To address the needs of future MANs, the Optical Communications Research Laboratory at Stanford University and Sprint Advanced Technology Laboratories are building HORNET (Hybrid Optoelectronic Ring NETwork). HORNET has a multiple access architecture, in which nodes access any WDM channel using a novel media access control protocol and fast tunable laser transmitters. HORNET transports data packets directly over the WDM ring, eliminating the SONET transport. This paper presents the HORNET architecture, the node design consisting of novel packet-over-WDM components, and the experimental testbed with results.

Experimental demonstration of an access point for HORNET-A packet-over-WDM multiple-access MAN

Hybrid opto-electronic ring network (HORNET) is a novel packet-over-WDM multiple-access network designed by the Stanford Optical Communications Research Laboratory (OCRL) to provide efficient bandwidth sharing among a large number of access points (APs) in a metropolitan area. The HORNET network eliminates the cost and complexity of SONET equipment by transmitting IP/ATM packets directly over the wavelength division multiplexing (WDM) layer. To improve performance above that of a conventional ring network, HORNET employs a multiple-access architecture using fast tunable transmitters and a novel carrier-sense multiple-access with collision avoidance (CSMA/CA) media access control (MAC) protocol. The OCRL has constructed a testbed to demonstrate the ability of a HORNET AP to transmit packets using a fast-tunable transmitter and a novel MAC protocol and to asynchronously receive packets in the packet-over-WDM architecture. The experimental results confirm that HORNET successfully achieves the following functions: 1) fast (low overhead) wavelength tuning using a fast-tunable transmitter; 2) collision-free packet transmission over a multiple-access network via the CSMA/CA MAC protocol; and 3) fast clock and data recovery using the embedded clock tone (ECT) technique.

Performance demonstration of a fast-tunable transmitter and burst-mode packet receiver for HORNET

We demonstrate error-free packet-over-WDM transmission using a fast-tunable transmitter and novel packet receiver. The transmitter tunes fine (0.8 nm) and. wide (/spl sim/30 nm) within 15 ns, while the receiver receives unframed packets by bit-synchronizing in 40 ns.

CSMA/CA MAC protocols for IP-HORNET: an IP over WDM metropolitan area ring network

As data traffic increases exponentially, IP over WDM transport will replace conventional SONET transport in metropolitan area networks. Such networks will require new media access control (MAC) protocols to efficiently share network bandwidth among multiple network nodes. This paper describes and evaluates novel and practical carrier sense multiple access with collision avoidance (CSMA/CA) MAC protocols for IP over WDM ring networks that handle variable size IP packets without complex variable optical delays or centralized algorithms. Simulation results show that the proposed IP-MAC protocols are efficient and comparable to our selected benchmark and will be implemented in the IP-HORNET testbed.

Experimental demonstration of a novel media access protocol for HORNET: a packet-over-WDM multiple-access MAN ring

As packet-based traffic in the metropolitan area network continues to exponentially increase, and as content and applications become more distributed, conventional metropolitan area networks fail to function efficiently. Sprint Advanced Technology Laboratories and Stanford Universitys Optical Communications Research Laboratory are developing a new network called HORNET (hybrid opto-electronic ring network), which is optimized for bursty, unpredictable, packet-based traffic patterns with distributed sources and destinations. HORNET uses fast tunable transmitters and a novel media access control scheme to realize a packet-over-WDM multiple-access ring architecture. The experimental demonstration of the novel media access control scheme is presented in this work.

WDM metropolitan area network based on CSMA/CA packet switching

The bursty nature of traffic in metropolitan area networks results in underutilized and inefficient SONET networks. The hybrid optoelectronic ring network (HORNET) is a network being developed at the Optical Communications Research Laboratory at Stanford University to address the problems of SONET transport in metropolitan area networks (MANs). HORNET performs packet switching using a fast-tunable wavelength transmitter, which hops to different wavelengths on a packet-by-packet basis. In this letter, we present simulation results which quantify the benefits of a wavelength tunable transmitter in a packet switched wavelength-division-multiplexed MAN. We show that a tunable transmitter is able to take advantage of imbalances in wavelength utilization, and provides a 45% improvement in packet latency characteristics. We also show that in order to maintain these benefits the tuning time of the transmitter cannot exceed 10% of the packet transmit time.

Architecture and protocols for HORNET: a novel packet-over-WDM multiple-access MAN

Future Internet technologies will cause an evolution in metropolitan area networks throughout the following decades. To keep pace with the development of Internet access technologies and devices, we have created a novel architecture called HORNET. Through the use of ultra-fast tunable transmitters and packet-over-WDM technology, HORNET is optimized for the metro area traffic of the future. We have developed a novel media access protocol and a novel survivability protocol for HORNET that we describe here. Also, we have generated successful experimental results, including a demonstration of the media access protocol and 4-ns wavelength switching durations in the tunable transmitter.

HORNET-A packet-switched WDM network: optical packet transmission and recovery

The hybrid optoelectronic ring network (HORNET) is a novel packet-switched wavelength-division-multiplexed metropolitan area network (MAN). HORNET uses a combination of optical and electronic packet-switching and an optical carrier sense multiple access with collision avoidance (CSMA/CA) media access scheme to efficiently provide large bandwidth to many users. The HORNET optical packets consist of 2.5-Gb/s payload data, an embedded 2.5-GHz clock tone, and a subcarrier-multiplexed (SCM) header for CSMA/CA. We are constructing an experimental testbed to demonstrate the ability of HORNET nodes to transmit and receive packets, to recover the destination node address carried by the SCM header, and to perform fast clock and data recovery with minimal overhead within the HORNET packet receiver.