Manivasakan Rathinam

Time-division multiplexing over packet-switched network (TDMoPSN) is an intermediate phase of transition from current synchronous TDM to future all-optical converged network. TDMoPSN is exclusively used to transport interactive voice traffic transparently over a PSN (e.g., IP, MPLS or Ethernet). The goal of this paper is to reduce rate-jitter that is introduced into a stream of packets carrying TDM payload. We have proposed two online algorithms, algorithm-A and algorithm-B, to reduce the rate-jitter and shown analytically that the rate-jitter achieved by algorithm-A is strictly less than the rate-jitter of online algorithm proposed by Mansour et al. [1]. We have used three stochastic processes, namely Poisson, Markov-modulated Poisson process (MMPP) and an arrival process with Pareto-distributed inter-arrival times (see [2–4]) for modeling the arrival of TDM packets (say, IP packets with single or many TDM frames as payloads) at the destination. We undertook statistical analysis of the proposed algorithms by modeling the jitter-buffer as $$M/\widetilde{D}/1/\, B_{on}$$M/D~/1/Bon and $$MMPP/\widetilde{D}/1/B_{on}$$MMPP/D~/1/Bon queues, to derive steady-state queue-length distribution, mean waiting time and distribution of inter-departure times. We also simulate the most realistic queueing model $$Pareto/\widetilde{D}/1/B_{on}$$Pareto/D~/1/Bon of our study and evaluated its performance with respect to the metrics: rate-jitter, mean waiting time, packet loss probability and steady-state queue-length distribution. Simulation results show that our proposed algorithms far outperforms the scheme proposed in [1]. We also present simulation results to verify the correctness of analytical queueing models. The algorithms proposed here are more general (for TDMoPSNs) and can be used to study TDMoIP, pseudowire, CES over metro Ethernet network (MEN), etc.

We address the problem of the performance analysis of the stochastic fair sharing (SFS) algorithm for fair link sharing. The SFS scheme has been proposed to carry out a fair link sharing and fair sharing among virtual private networks. Depending upon the current utilization and provisioned capacities of the classes, the SFS admission control algorithm decides which sessions to accept and which to reject. In this letter, we undertake the performance evaluation of the SFS scheme analytically. We explore the tradeoff between fairness and the blocking probability by varying the trunk reservation parameter. The results show that the analytical performance measure agrees well with the simulation results.

We derive the distribution of inter-departure times of a finite-buffer single-server queue with Poisson arrival process and queue-length-dependent service times, where the server goes to vacation if either the queue is emptied or a limited number (R1) of packets are served, whichever occurs first, in the current busy period. We consider two types of vacation distributions: 1) deterministic and 2) exponential. Queue-length distribution at embedded points is derived first, then, the distribution and variance of inter-departure times are derived, for both types of vacations. The simulation results are in good agreement with the derived analytical results. The above framework would be useful at the receiver in modeling and analyzing the jitter and the waiting time of time-division multiplexing (TDM) emulated packets in TDM over packet-switched network (TDM over PSN) technology as a function of a buffer size.

The design of the medium-access control (MAC) protocol is the most crucial aspect for high-speed and high-performance local and metropolitan area networks, since the decisions made at this level determine the major functional characteristics of these networks. Most of the MAC protocols proposed in the literature are not suitable for multimedia applications, since they have been designed with one generic traffic type in mind. As a result, they perform quite well for the traffic types they have been designed for, but poorly for other traffic streams with different characteristics. In this paper, we propose an integrated MAC protocol called the Multimedia-MAC (M-MAC), which integrates different MAC protocols into a hybrid protocol in a shared-medium network to efficiently accommodate various types of multimedia traffic streams with different characteristics and quality-of-service demands, namely, a constant-bit-rate traffic, bursty traffic (say, variable-bit-rate traffic), and emergency messages (say, control messages). We have developed a mathematical framework for the analysis and performance evaluation of our M-MAC protocol, which involves a queueing system with vacation. We have applied our M-MAC design approach to a wavelength-division multiplexing network, and evaluated its performance under various traffic conditions. © 2006 IEEE.

We propose and demonstrate a generalized framework for performance limit evaluation and comparison of multihop optical repeated and regenerated links. The model developed is implementation agnostic and applies to multihop optical links of varied forms, including fiber, free space, and underwater links. The framework estimates the best-case performance gains of deploying an all-regenerative link over an all-repeater link for any given implementation. The implementation-independent technique is then illustrated using guided and free-space optical links. An abstract model is developed first with the evolution of signal, noise power, and bit error rate down the link compared and contrasted for both cases. The model is then evaluated using physical parameters for a typical fiber optic intensity-modulated direct detection link, and the obtained all-regenerator link performance advantage is translated to extra reach and lower transmission power requirements. Further, certain approximations are provided to reduce computational complexity and improve the analytical tractability of the procedure, which could be particularly helpful when employed in specialized hardware or for dynamic reconfiguration networks. Finally, the framework's versatility is established by employing it in analyzing an ideal free-space link and comparing amplify and forward links against decode and forward counterparts. Similar results are also reproduced on a commercial optical link simulation suite. Detailed literature on link analysis is provided for fiber, free space, and underwater links, bringing out their similarities. We conclude by elaborating on various current and emerging application domains and certain limitations of the proposed technique.