Slotted optical switching with pipelined two-way reservations

Angelopoulos, John; Kanonakis, Konstantinos; Leligou, Helen C.; Linardakis, C.; Pountourakis, Ioannis E.; Stavdas, Alexandros

doi:10.1109/jlt.2006.881847

Cited by 12 publications

(8 citation statements)

References 16 publications

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“…If the source node is already utilizing the time-slots, the control node looks for the time-slots virtually allocated to other source nodes in the VCP. And then the control node allocates the available time-slots to the source node only if the second chance is not locked by the First-Hop-Node (13). The number of allocating time-slots depends on the request of the source node, and a specific mechanism is the vendor-specific area and remained for future study.…”

Section: Flow Control Scheme Supporting the Tsa Algorithmmentioning

confidence: 99%

“…In order to resolve the contention problem, a new paradigm, which is called slotted optical burst switching (SOBS), is suggested as new OBS network architecture [11][12][13][14][15][16]. SOBS divides a wavelength into time-units (time-slots) at the time-axis, transmits a data burst contained in a time-slot, and switches the incoming time-slots to the preferred output ports at intermediate nodes [11].…”

Section: Introductionmentioning

confidence: 99%

“…A guard-time is inserted between the time-slots otherwise a data burst in a time-slot can be partly lost because of switching delay. For the synchronization of the time-slots among nodes, a small length of FDL is needed per input port [13]. Regarding SOBS, Turner et al [11] first proposed a cost-effective SOBS solution minimizing the usage of FDL and not having WC.…”

Section: Introductionmentioning

confidence: 99%

“…However, this approach is not applicable to mesh networks consisting of multiple core nodes because of the complexity of adjusting the time interval. Angelopoulos et al [13] proposed to make an end-toend reservation of the time-slots for each data burst, so that resources in the core nodes are not wasted by dropping the data bursts already having passed multiple nodes. However, because of burst-by-burst slot reservation from a source node to a destination node, buffering delay and jitter can be incredibly increased, especially when the round trip time (RTT) is very long.…”

Section: Introductionmentioning

confidence: 99%

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A tree-based slot allocation algorithm for loss-free slotted OBS networks

2009

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Optical burst switching (OBS) is regarded as one of the most promising switching technologies for next generation optical networks. However, the data burst contention problem is still unresolved thoroughly even though slotted OBS (SOBS) is studied as a new paradigm reducing the blocking rate. In this article, we propose a tree-based slot allocation (TSA) algorithm for loss-free SOBS networks, where the TSA algorithm originally avoids contention of the time-slots by reserving the time-slots with different timeslot positions for the source nodes, respectively. In order to manage the time-slots efficiently, we also propose an OBS superframe, which is a cyclic period and consists of multiple time-slots transmitted by the source nodes toward the same incoming port of a destination node. In addition, we attempt to optimize multiplexing of the OBS superframes to reduce wavelength consumption. On the other hand, when incoming traffic is beyond expectation, a source node may need more time-slots to prevent packet loss because of buffer overflow. For reallocation of the time-slots, we propose a flow control scheme managing some number of shared time-slots, where a control node adaptively allocates (or redeems) the time-slots to (or from) source nodes by utilizing the shared H. Jeong (B) Long Term Evolution R&D Laboratory, DMC, time-slots based on fluctuating traffic condition. Simulation results show that the blocking rate of the proposed TSA-OBS scheme is zero with acceptable queueing delay at moderate traffic offered loads. In addition, multiplexing optimization simulated in the 14-node NSFNET achieves a 63% reduction of wavelength consumption. Moreover, the proposed flow control scheme assisting the TSA algorithm maintains a target upper-bound of queueing delay at the source node, so that packet loss caused by buffer overflow is prevented.

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Section: Flow Control Scheme Supporting the Tsa Algorithmmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A tree-based slot allocation algorithm for loss-free slotted OBS networks

2009

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“…The need to retransmit lost bursts makes delay guarantees impossible whether done at the optical layer or by TCP. Adopting a two-way reservation approach [2,3] solves the loss problem but the reservation delay is only acceptable for networks with a circumference of 1000-2000 km.…”

Section: Introductionmentioning

confidence: 99%

Reservations inside clusters of all‐optical core nodes achieve distributed burst aggregation and switching improving efficiency and loss

Stavdas

Kanonakis

Koukouvakis

et al. 2007

Trans Emerging Tel Tech

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SUMMARYClustering neighbouring nodes of an all-optical core network into medium-sized rings controlled by a master node allows two-way reservation-based control to aggregate bursts destined for other clusters in a lossless way with tolerable delay. The densely packed bursts can then be sent over static or switched light paths and be received in the destination cluster ring without the delay of end-to-end reservations. This hybrid approach where two-way reservations are geographically limited inside clusters only avoids both the handicap of heavy loss of one-way Optical Burst Switching (OBS) and the intolerable delay and multiplexing gain of end-to-end reservations. In addition, the number of multi-port space-switching all-optical nodes is reduced delegating part of this function to the distributed control of the laser sources of the ring under the guidance of the medium access protocol.

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