A critical challenge for video-on-demand (VoD) services is to provide an entertainment service with minimum playback delay. A passive optical network (PON) that employs a high-speed optical fiber from an optical line terminal (OLT) to a number of optical network units (ONUs) can offer high bandwidth for multimedia applications (such as VoD services) in an access network. We propose two novel video streaming techniques, called OLT broadcasting with ONU fast patching (BFP) and prediction-based OLT broadcasting and ONU fast patching (PBFP). The BFP scheme utilizes the ONU fast patching scheme at each ONU, and proposes a heuristic algorithm to find near optimum solutions of related optimization problem so that the worst-case playback delay (WPD) is minimized. The PBFP adds a prediction level for video popularity to the BFP scheme and uses a seamless channel transition technique to seamlessly change the number of channels allocated to videos. We study the efficiency of the proposed schemes when they are used in a shared wavelength division multiplexed passive optical network (Shared-WDM-PON) that adapts the broadcast nature of a GPON's downstream wavelength to WDM-PONs. Our simulation results indicate that the proposed schemes can improve both WPD and average playback delay performance parameters.

Among the many different bandwidth access schemes used in optical packet switched networks nowadays, the issue of transmitting optical packets (called slots in this paper) smoothly to an egress switch appears to be overlooked. Here, we explain the benefits of providing an even (smooth) slot transmission, and propose three methods to achieve an even transmission from an ingress switch of a multi-wavelength/fiber network. An index parameter is introduced in each method, and a formulation is provided to gauge how even a transmission is among different combinations of frame periods, wavelengths, and fibers. These formulations provide us with a new approach to compare different bandwidth access schemes. An example is provided for the comparison of the distributed bandwidth access, and the timer-based plus threshold-based bandwidth access schemes.

We study and evaluate the performance of three potential candidates of resource-sharing algorithms in agile single-hop slotted buffer-less all-optical packet switched metro networks. Both reservation-based (centralized) and collision-based (distributed) schemes are considered. In the centralized scheme, all decisions are made at the core switch and loss can be avoided through reservations. On the other hand, decisions are made at the edge switches in the distributed scheme, and we need to retransmit the dropped traffic. We also implement an integrated architecture that combines the good attributes of both schemes and characterize this architecture by various measures such as delay and loss probabilities at the edge switches.

Optical time division multiplexing can be deployed in an all-optical network to provide a finer granularity and improve the bandwidth usage. In contention-based slotted all-optical networks, transmitted traffic (referred to as slot in this paper) on the same wavelength and time-slot from different ingress switches may collide at the optical switches and therefore a number of slots will be lost. In this paper, we study various software techniques to reduce the slot loss rate at an optical switch. We prove some lemmas related to the contention avoidance issue. We show that the ingress switches can have an important role in the loss rate reduction issue in the slotted all-optical networks by balancing the traffic on the wavelength channels and the symmetric traffic transmission. We analyze for the first time the lower-bound on the slot loss rate. We show how to achieve the lower-bound on the loss rate in practice.

A new framework, called distributed TDM (DTDM), is proposed to access a slotted all-optical packet switching network within the DiffServ domain. In DTDM, each ingress switch measures the bandwidth (in slots per frame) of the traffic torrents (a torrent is the traffic between each pair of ingress and egress switches) at each frame time. Then the slots assigned to each torrent are distributed throughout the frame and among the output wavelengths and fibers. A schedule is determined so that each torrent knows in which wavelength/fiber and time-slot can transmit its traffic. DTDM uses packet schedulers to provide packet differentiation

In this paper, we propose a new scheduling technique, called output-controlled round robin (OCRR), for the support of class-based IP networks with variable packet sizes. This technique can be used in edge switches of an optical network to assemble traffic from aggregated flows into bursts/slots. Traffic flows from different classes are scheduled in logical frames. In each logical frame, a flow obtains a grant quantum with respect to its average rate and bandwidth usage in order to pass its traffic. The round robin technique is extended to include smaller cycles to send packets from aggregate flows one by one, thus, eliminating bursty effect from the same flow on the output bandwidth. The amount of the output traffic from each flow is also controlled. Our performance evaluation demonstrated that this output-controlled technique has better performance results than the deficit round robin algorithm in reduction of queuing delay and burst size from the same flow.