Architecture and Performance Evaluation of a Novel Optical Packet Switch with Input Concentrators

In this paper, we propose a novel optical packet switch (OPS) architecture with input concentrators, which employ multi-input single-output optical buffers to aggregate all the incoming traffic into a small size switching fabric. Accordingly, the physical size, the number of the needed wavelength converters, and the economic cost of the total OPS node are decreased dramatically. However, the deployment of input concentrators introduces additional packet loss and delay, except from the contention at the switch output. A Markov model is presented to study the packet loss ratio (PLR) and average packet delay given by the input concentrators. The corresponding closed form expressions are given. The model also demonstrates that the system performance can be greatly improved by increasing the buffer size when the traffic load is not larger than 0.69315. The analytical values are compared with the simulation results. All the obtained results show that the proposed model provides satisfactory approximations under different network scenarios. Moreover, the economic cost savings of the proposed OPS node at the present time and its evolution as a function of time are also discussed in detail. The proposed architecture can also be applied in a packet enhanced optical transport network (OTN).

Design of optical packet switch in presence of dispersion compensation and amplifier noise

Optical communication gained popularity in past few years. Optical communication has many distinct advantages over copper cable based electronic communication. Optical switches are integral part of optical networks which are used for rerouting of packets and also plays important role in contention resolution of the packets. These switch uses fiber delay lines (FDLs) act as optical memory. In past analysis of the switch is done by considering loss, power and noise and finally bit error rate (BER); however dispersion was neglected which is an important parameter in high speed communication. In this paper, design analysis is done by considering dispersion compensation along with optical amplifier noise.

Solitons based optical packet switch analysis

Due to the evolution of data centric applications demand for high speed data transfer and more bandwidth is increasing continuously. The unavailability of components like tunable wavelength converters (TWCs) restrict the transfer of parallel information using wavelength division multiplexing (WDM), therefore in the present scenario optical orthogonal frequency division multiplexing can be used. Moreover in optical communication narrow Gaussian pulses are transmitted, which spread with distance and leads to the broadening of the pulse and pulse peak power goes down and thus limits the system. In this paper a Soliton based optical communication system is proposed and its comparison with Gaussian pulse is presented and it has been found that soliton pulse has lesser bit error rate in comparison to Gaussian pulses.

Hybrid buffer and AWG based add-drop optical packet switch

Optical packet switching (OPS) exhibits the ability to be utilized as a data transmission technique for next-generation. The core router/switch plays a significant role in packet routing and buffering in OPS. Arrayed waveguide grating (AWG) is realized as a promising core element for fast optical switching, with its intrinsic capacity to achieve wavelength routing of different wavelengths in parallel. This paper proposes an AWG-based add-drop optical packet switch, including a hybrid buffer, to resolve contention among packets. In a hybrid buffer, both optical and electronic buffers are used for the buffering of contending packets. AWGs are affected by crosstalk that can significantly impair system operation. The physical layer analysis is discussed in the presence of crosstalk, and the performance of the switch is evaluated in terms of bit error rate. The desired minimum input power is calculated for the switch’s correct operation for both optical buffer and electronic buffer. Finally, the packet loss probability (PLP) of the hybrid buffer is examined under various buffering conditions. Results reveal that with the increase in the optical power of the input signal, crosstalk power increases linearly for optical and electronic buffers. The increased crosstalk power is higher for electronic buffers than the optical buffer. The use of electronic memory in the hybrid buffer allows the hybrid buffer to increase its buffer size thus, reducing the PLP.

A critical review of optical switches

Optical packet switching has gained lot of popularity in last a few years due to its advantages like, large speed, more bandwidth and very less crosstalk. But due to immature optical fabrication and designing technology OPS is still beyond reality. However, many of the optical components are commercialized and some of them are still in laboratory. Thus, for optical switches which are considered as future generation routers, many switch architectures are proposed by using different sets of optical components. This paper presents a detailed review of notable switch designs in past 20 years, and also presents a comprehensive literature survey of the notable papers related to optical packet switch designs.

Load-Optimization in Reconfigurable Networks

Emerging reconfigurable data centers introduce the unprecedented flexibility in how the physical layer can be programmed to adapt to current traffic demands. These reconfigurable topologies are commonly hybrid, consisting of static and reconfigurable links, enabled by e.g. an Optical Circuit Switch (OCS) connected to top-of-rack switches in Clos networks. Even though prior work has showcased the practical benefits of hybrid networks, several crucial performance aspects are not well understood. In this paper, we study the algorithmic problem of how to jointly optimize topology and routing in reconfigurable data centers with a known traffic matrix, in order to optimize a most fundamental metric, maximum link load. We chart the corresponding algorithmic landscape by investigating both un-/splittable flows and (non-)segregated routing policies. We moreover prove that the problem is not submodular for all these routing policies, even in multi-layer trees, where a topological complexity classification of the problem reveals that already trees of depth two are intractable. However, networks that can be abstracted by a single packet switch (e.g., nonblocking Fat-Tree topologies) can be optimized efficiently, and we present optimal polynomialtime algorithms accordingly. We complement our theoretical results with trace-driven simulation studies, where our algorithms can significantly improve the network load in comparison to the state of the art.

PENGARUH PENGGUNAAN CODEC STANDART ITU G.729 TERHADAP SISTEM KOMUNIKASI VOIP

Voice over Internet Protocol (VoIP) is a technology that is capable of passing voice traffic, in the form of packets through the network Internet Protocol (IP). IP network itself is a data communications network based packet-switch. The voice signal before experiencing bundled voice coding or format conversion of sound into digital form that can be passed over an IP network. Telephony, Internet telephony, or termed VoIP (Voice Over Internet Protocol.This communication system use VoIP (Voice over Internet Protocol), ie voice calls over data services (internet). This communication was developed using Android-based devices. Based on characteristics, android devices are open source, so users do not need to have a license to be able to have android-based devices. In addition, the android device that must be connected to a SIP (Session Iniation Protocol) is a data service that can be done with a paid subscription of the user of the operator using a conventional pulse. Telecommunications designed will use a hybrid system, the merger between VoIP communications with data communications GSM network. With basic calculations where Coding standards G 729, is a standard that can be used for voice communication system through data networks with rate of 8 Kbps. The implementation of the G729 codec is effect on communication systems VOIP.