Acampora, A.S., Karol, M. J. and M.G.Hluchyj, "Terabit Lightwave Networks: The Multihop Approach," AT&T Technical Journal, Vol. 66, No.6, pp. 21-34, Novem- ber/December 1987.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....(or hot potato) routing, it can operate with as few as one buffer per output port. The toroidal topology of the MSN ensures that a deflected packet will nominally take four extra hops to travel around the block if it needs to return to its point of deflection. ShuffleNet: ShuffleNet, proposed in [AKH87], embeds a perfect shuffle interconnection within a fully broadcast physical topology. This can be accomplished with stations having two sets of independently tuned (fixed) transceivers and at least twice as many WDM channels as the number of stations. The resulting multichannel, multihop network ....

....The major single limitation is the complexity of scaling up to large user populations and therefore high throughputs. If a single wavelength is used, then the throughput is limited by the maximum data rate achievable with affordable digital circuit technology, that is, in the order of a few Gb s [AKH87]. Capacity can be upgraded by using multiple wavelengths and implementing time and frequency division access schemes as shown in LAMBDANET, SWIFT and Rainbow. However, to achieve good efficiency in bursty traffic environments, these schemes require frequency agile lasers and detectors over broad ....

[Article contains additional citation context not shown here]

Acampora, A.S., Karol, M. J. and M.G.Hluchyj, "Terabit Lightwave Networks: The Multihop Approach," AT&T Technical Journal, Vol. 66, No.6, pp. 21-34, Novem- ber/December 1987.

....OF OPTICAL PACKET SWITCHES WITH ADD DROP FUNCTIONALITY As illustrated in Fig. 2, add drop packet switch nodes can be used to construct network partitions or subnetworks taking the form of, e.g. metropolitan area networks (MAN) and on a large scale even wide area networks (WAN) 41] [44]. The packet switch architectures described in the previous sections can almost directly be transformed into add drop switches by dedicating a number of inlets as add inlets and a number of outlets as a drop outlets. Nevertheless, some differences in the architectures occur as discussed below. ....

....directly be transformed into add drop switches by dedicating a number of inlets as add inlets and a number of outlets as a drop outlets. Nevertheless, some differences in the architectures occur as discussed below. As an example of a network that uses add drop switches the Shufflenetwork [41] [44] is shown in Fig. 12. The figure illustrates a general WDM Shufflenetwork with eight add drop switch nodes. The network consists of 2 2 nodes (not including add drop) and has two columns (last column is not counted since it is a replica of the first) It is noted that the generalized ....

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A. S. Acampora and M. G. Hluchyj, "Terabit lightwave networks: the multihop approach," AT&T Tech. J., vol. 66, no. 6, pp. 21--34, Nov./Dec. 1987.

....of TeraNet is the ability to provide an aggregate network capacity which is far in excess of the peak rate at which any one user 2 may access the network. This is achieved through establishment of multiple channels, each at the user access rate, operating simultaneously within the optical ether [4], 5] A variety of channeling techniques in lightwave networks has been proposed based on Frequency Division Multiplexing (FDM) and Time Division Multiplexing (TDM) Channels in TeraNet are established through the use of WDMA Subcarrier FDMA (WD SFDMA) 6] WD SFDMA is a two level channel ....

Acampora, A. S., Karol, M.J. and Hluchyj, M.G., "Terabit Lightwave Networks: the Multihop Approach", AT&T Technical Journal, Volume 66, Issue 6, November /December 1987, pp. 21-34.

....of TeraNet is the ability to provide an aggregate network capacity which is far in excess of the peak rate at which any one user may access the network. This is achieved through establishment of multiple channels, each at the user access rate, operating simultaneously within the optical ether [4], 5] A variety of channeling techniques for lightwave networks 1 TeraNet: A Multihop Multichannel ATM Lightwave Network 2 have been proposed based on Wavelength Frequency Division Multiplexing and Time Division Multiplexing methods [6] 7] In TeraNet, channels are established through the use ....

A.S. Acampora, M.J. Karol and M.G. Hluchyj, "Terabit Lightwave Networks: the Multihop Approach," AT&T Technical Journal, Volume 66, Issue 6, November/December 1987, pp. 21-34.

....need to make several hops to reach its destination. This will require routing through intermediate nodes, each repeating the packet on a new wavelength, until the packet is finally transmitted on a wavelength that can be received by the ultimate destination. We call such networks multihop networks [1]. The assignment of transmit and receive wavelengths to each node s transmitter and receiver results in a virtual topology on top of the physical topology. In the past, several virtual topologies have been proposed for multihop networks for optical stars and busses [19, 7, 10] The Shuffle net is ....

Acampora A.S., Karol M.J., Hluchyj M.G., "Terabit Lightwave Networks: The Multihop Approach", AT&T Technical Journal, vol. 66, no. 6, Nov/Dec 1987, pp. 21-34.

....(say node 0) is shown to reach simultaneously three nodes (9, 10 and 11 in this case) This is because of the broadcast nature of the passive star which is taken advantage of here. Several researchers have suggested virtual embeddings which require high speed tunable transmitters and or receivers [1, 11, 17, 29, 31, 36, 44]. As shown in Figure 5, the resource requirements for an N node passive star network design vary greatly. For high speed transmission, it is desirable that the interface hardware be as simple and fast as possible. Embeddings using fixed allocation TWDM appear to be the most promising at this ....

.... N 1 agile 1 fixed Aloha [45] N 1 agile 1 fixed 2 fixed DT WDMA [16] N 1 fixed 1 agile 1 fixed CDMA [41] 1 1 fixed 1 fixed All Optical ShuffleNet [13] N=2 1 fixed 1 fixed Knockout Switch [23] 4N 1 fixed 4 agile LambdaNet [34] N 1 fixed N fixed Swift [18] 2 1 agile 2 agile perfect shuffle [1] 2N 2 fixed 2 fixed de Bruijn [44] 2N 2 fixed 2 fixed p shuffle [31] N=p 1 fixed 1 fixed Bus Mesh [20] p N 1 fixed 1 fixed Figure 5: Resource requirements for an N node passive star network 1. an appropriate virtual topology which reduces the network diameter, requires simple hardware, ....

Acampora, A., Karol, M., and Hluchyj, M., "Terabit Lightwave Networks: The Multihop Approach", AT & T Technical Journal, Vol. 66, No. 6, November/December 1987.

.... 1 fixed 2 fixed DT WDMA[5] N 1 1 fixed 1 agile 1 fixed DAS[21] N 1 2 fixed 1 agile 1 fixed Rainbow[10] N 1 agile 1 agile FOX[2] N 1 agile 1 fixed CDMA[16] 1 1 fixed 1 fixed LambdaNet[14] N 1 fixed N fixed Knockout Switch[8] 4N 1 fixed 4 agile Swift[6] 2 1 agile 2 agile ShuffleNet[1] 2N 2 fixed 2 fixed de Bruijn[18] 2N 2 fixed 2 fixed p shuffle[12] N=p 1 fixed 1 fixed optimal[15] 2N 2 fixed 2 fixed Optical Shufflenet[4] N=2 1 fixed 1 fixed Bus Mesh p N 1 fixed 1 fixed Table 1: Resource requirements for an N node passive star network A star coupler is also highly ....

....virtual topology of the network. When a node needs to transmit a message to a destination that does not directly receive packets from the source, the message is relayed by intermediate nodes. Multihop networks have been proposed using different regular virtual topologies such as a perfect shuffle [1] or de Bruijn graph [18] The use of regular virtual topologies provides several advantages including simple routing and predictable mean and maximum path length. While these networks can avoid the limitations of tunable 3 transmitters, they still require the WDM system to support a large number ....

[Article contains additional citation context not shown here]

Anthony S. Acampora, Mark J. Karol and Michael G. Hluchyj, "Terabit Lightwave Networks: The Multihop Approach", AT&T Technical Journal, vol. 66, no. 6, pp. 21-- 34, Nov/Dec 1987

....network embedded in the passive optic network. The switches of the multihop network are represented by the user stations (thus, they are located at the periphery of the passive broadcast medium) the links consist of dedicated wavelength channels established between pairs of stations [AKH87]. Thus, over the physical broadcast topology, there is a virtual topology that determines the actual connectivity between the stations in the network. As in conventional store and forward networks, packets may need to be queued at intermediate nodes. As an alternative for packet queueing, ....

....to the number of hops for packet transmissions. Thus, the virtual topology should be designed to minimize the number of hops. 1.2.2. 1 Virtual topologies for the multihop networks The regular virtual topologies that have been proposed for the multihop optical network are the ShuffleNet [AKH87], the de Bruijn graph [SR91] the torus [Max87, Aya89, GL92] the hypercube [LG92] the ring [KP92] and the dual bus [BMS92] The most prominent example of virtual multihop network is ShuffleNet, proposed in [AKH87] ShuffleNet exploits WDM to embed a perfect shuffle interconnection within a ....

[Article contains additional citation context not shown here]

A. S. Acampora, M. J. Karol, and M. G. Hluchyj. "Terabit Lightwave Networks: The Multihop Approach." AT&T Technical Journal, 66(6):21--34, Nov./Dec. 1987.

....require some packets to travel across several hops. In general, each hop incurs the penalty of an electro optical conversion. Obviously, the virtual topology should permit routes that have as few hops as possible. The most prominent example of virtual multihop network is ShuffleNet, proposed in [AKH87]. ShuffleNet exploits WDM to embed a perfect shuffle interconnection within a fully broadcast physical topology. Figure 1 shows an example of an eight station perfect shuffle virtual topology implemented as a physical tree and illustrates how different virtual topologies can be embedded in a given ....

....perform very well under most of the criteria. The major single limitation however is in scaling up to large user populations. If a single wavelength is used, then the throughput is limited by the maximum data rate achievable with digital circuit technology, that is, in the order of a gigabit s [AKH87]. Capacity can be upgraded by using multiple wavelengths and implementing time and frequency division access schemes as shown in LAMBDANET and Rainbow. To achieve good efficiency in bursty traffic environments, however, these schemes require frequency agile lasers and detectors over broad ranges ....

Anthony S. Acampora, Mark J. Karol and Michael G. Hluchyj, "Terabit lightwave networks: The multihop approach", AT&T Technical Journal, vol. 66, no. 6, pp. 21-34, November /December 1987.

....network embedded in a passive optical network. The switches of the multihop lightwave network are represented by the user stations (thus, they are located at the periphery of the passive broadcast medium) and the links consist of dedicated wavelength channels established between pairs of stations [3]. Thus, over the physical broadcast topology, there is a virtual topology that determines the logical connectivity between the stations of the network. The most prominent example of a virtual multihop network is ShuffleNet, proposed in [3] ShuffleNet exploits WDM to embed a perfect shuffle ....

....wavelength channels established between pairs of stations [3] Thus, over the physical broadcast topology, there is a virtual topology that determines the logical connectivity between the stations of the network. The most prominent example of a virtual multihop network is ShuffleNet, proposed in [3]. ShuffleNet exploits WDM to embed a perfect shuffle interconnection within a fully broadcast physical topology. The virtual topology can be modeled as a directed graph (digraph) in which the existence of an arc from one node to another implies the cotuning of the corresponding stations ....

A. Acampora, M. Karol, and M. Hluchyj. Terabit lightwave networks: The multihop approach. AT&T Technical Journal, 66(6):21--34, Nov./Dec. 1987.

....network embedded in the passive optic network. The switches of the multihop network are represented by the user stations (thus, they are located at the periphery of the passive broadcast medium) the links consist of dedicated wavelength channels established between pairs of stations [AKH87]. Thus, over the physical broadcast topology, there is a virtual topology that determines the actual connectivity between the stations in the network. Like in conventional store and forward networks, packets may need to be queued at intermediate nodes. As an alternative for packet queueing, ....

....The effective network capacity is inversely proportional to the number of hops for packet transmissions. By choosing an appropriate virtual topology it is possible to minimize number of hops and to achieve very high throughputs. The network capacity grows with O(N= log N) if ShuffleNet [AKH87] or de Bruijn graph [SR91] virtual topology is used. The multihop network can be implemented with a small number of fixed transmitters and receivers per station. Practically, the minimum number required is one transmitter and one receiver per station. The advantages of the multihop architecture is ....

A. Acampora, M. Karol, and M. Hluchyj. Terabit lightwave networks: The multihop approach. AT&T Technical Journal, 66(6):21--34, Nov./Dec. 1987.

....network embedded in a passive optical network. The switches of the multihop lightwave network are represented by the user stations (thus, they are located at the periphery of the passive broadcast medium) and the links consist of dedicated wavelength channels established between pairs of stations [3]. Thus, over the physical broadcast topology, there is a virtual topology that determines the logical connectivity between the stations of the network. The most prominent example of a virtual multihop network is ShuffleNet, proposed in [3] ShuffleNet exploits WDM to embed a perfect shuffle ....

....wavelength channels established between pairs of stations [3] Thus, over the physical broadcast topology, there is a virtual topology that determines the logical connectivity between the stations of the network. The most prominent example of a virtual multihop network is ShuffleNet, proposed in [3]. ShuffleNet exploits WDM to embed a perfect shuffle interconnection within a fully broadcast physical topology. The virtual topology can be modeled as a directed graph (digraph) in which the existence of an arc from one node to another implies the cotuning of the corresponding stations ....

Anthony S. Acampora, Mark J. Karol, and Michael G. Hluchyj. Terabit lightwave networks: The multihop approach. AT&T Technical Journal, 66(6):21--34, Nov./Dec. 1987.

....in which the data stream does not undergo any processing (like control field inspection or storing and forwarding) along the transmission path on the optical topology. Only all optical amplification and wavelength filtering are allowed. Thus, the topology can be viewed as a mass of glass [AKH87] In order to provide in a PON full interconnectivity among the attached stations, without traversing multiple optical paths, the physical topology must be restricted to three choices: star, bus or tree (or proper combinations of thereof) In contrast, the virtual topology, which is the ....

....network embedded in the passive optic network. The switches of the multi hop network are represented by the user stations (thus, they are located at the periphery of the passive broadcast medium) the links consist of dedicated wavelength channels established between pairs of stations [AKH87] The multi hop network differs from a conventional P S mesh network in that it uses streamlined network protocols especially designed for high speed operations. It features simple network controls, and efficient packet buffering strategies at the station. Namely, packet forwarding is ....

[Article contains additional citation context not shown here]

Anthony S. Acampora, Mark J. Karol, and Michael G. Hluchyj. Terabit lightwave networks: The multihop approach. AT&T Technical Journal, 66(6):21--34, Nov./Dec. 1987.

....upper bound in performance, which is much simpler to compute than the optimum, and use this bound in the evaluation. We also compare the performance of the WDM reconfigurable network with a fixed topology network with the same number of nodes and links; for the evaluation, we chose the ShuffleNet [17]. The routes in the ShuffleNet were computed using linear integer programming [3, 4] 5.1 Evaluation Scenarios and Performance Measures The first step in the evaluation is defining the evaluation scenarios and performance measures under which the algorithms are to be compared: Evaluation ....

A.S. Acampora, M.J. Karol, M.G. Hluchyj, "Terabit Lightwave Networks: The Multihop Approach," AT&T Technical Journal, vol. 66, issue 6, Nov/Dec 1987, pp 21-34.

....networks. Wavelengthdivision multi access (WDMA) networks employ efficient multi channel access protocols to achieve superior performance at a low system complexity [1, 2] Multihop networks based on WDM are topologically equivalent to the space switched multi stage networks (e.g. the shufflenet) [3, 4]. The virtual point to point approach takes advantage of the combinatorial property provided by wavelength selectivity to achieve reconfigurable networks with direct virtual connectivity [5] According to the routing scheme, WDM networks are classified into wavelength routing (WR) and ....

A. S. Acampora, M. J. Karol, and M. G. Hluchyj, "Terabit lightwave networks: The multihop approach," AT&T Technical Journal, vol. 66, pp. 21--34, November/December 1987.

.... from the details of the underlying distributed memory communication structure and view the system as a pool of processors that share the same memory space [14] Multihop networks based on WDM are topologically equivalent to the space switched multi stage networks (e.g. the perfect shuffle) [15]. Fixed wavelength channels were used to define the connectivity over a shared folded bus. Cumulative message transfer delay is significant due to the delay at each hop, such as routing and the electronic optic and optic electronic conversions at each stage, making this class of networks more ....

A. S. Acampora, M. J. Karol, and M. G. Hluchyj, "Terabit lightwave networks: The multihop approach," AT&TTechnical Journal, vol. 66, pp. 21--34, November/December 1987.

....must defer to messages that are already in the network. These characteristics have led to this technique also being referred to as hot potato routing. Because deflection routing eliminates the need for switch buffering, investigation of its performance is currently receiving widespread attention [4, 6, 7, 8, 11, 12, 19, 21, 26, 30]. The typical strategy of these analyses is to make uniformity assumptions about the network that allow it to be decomposed, reducing the problem from studying the entire network to studying only a single switch. Another assumption that is commonly made is that messages unable to enter the network ....

Karol, M., Acampora, A., and Hluchyj, M. Terabit lightwave networks: The multihop approach. AT&T Technical Journal 67, 1 (1987), 23--34.

....its destination should be small. Such assignments are based on an interconnection topology. Since this topology is not directly related to the physical connection of nodes, it is referred to as a virtual topology. A number of virtual topologies have been proposed [8] These include: ShuffleNet [9, 10, 7], Hypercube [11] Generalized Hypercube [8] DeBruijn [12] and MSN (Manhattan Street Network) 13] There are advantages and disadvantages for the different options. A review can be found in [6, 8] Of the many options, ShuffleNet is one of the most popular topology [6] It has been shown that a ....

....for the different options. A review can be found in [6, 8] Of the many options, ShuffleNet is one of the most popular topology [6] It has been shown that a 64 node ShuffleNet has better performance than the corresponding MSN [14] The ShuffleNet was first proposed by Acampora et al. [9] and later extended and generalized by Hluchyi and Karol [10, 7] Conceptually, it is a uni directional, cylindrically connected Omega network [15] In general, there are N = p m Theta m nodes arranged in p m rows and m columns. Interconnection between adjacent columns is a perfect shuffle ....

[Article contains additional citation context not shown here]

A.S. Acampora, M.J. Karol, and M.G. Hluchyj. "Terabit Lightwave Networks: The Multihop Approach". AT & T Technical Journal, 66(4):21--34, November 1987.

....The advocates of this approach claim that changes in the virtual topology can be carried out dynamically to follow the observed changes in the traffic pattern. Thus, the network can adapt its topology to the traffic conditions in a way that maximizes its performance. Details of wdm can be found in [VWD91, MoG90, BFM90, LaA91, ZhA90, HlK88, Aca87, AKH87]. These studies raise the following two problems: 1. The embeddings of the hypercube and ShuffleNet are discussed in [VWD91] and [BFM90] respectively. However, the efficient bit controlled routing algorithms developed for these networks are solely concerned with minimizing the number of hops and ....

....= 2.00 14 7 = 2.00 2 14 7 = 2.00 14 7 = 2.00 14 7 = 2.00 2 2 (a) 0 1 2 3 4 5 6 7 0 1 2 3 (b) 14 7 = 2.00 14 7 = 2.00 Avg = 2.00 2 1 1 3 3 2 2 2 3 3 1 1 2 2 3 3 3 3 2 1 1 3 3 2 2 2 3 3 1 1 2 2 2 Figure 3: The topology of an 8 node ShuffleNet. Another variation on the shuffle theme was presented in [AKH87] under the name of ShuffleNet and discussed further in [Aca87, HlK88] In ShuffleNet, N = kp k nodes are arranged in k columns of p k nodes. Each node is addressed with its row and column coordinate pair (r; c) Columns are ordered left to right from 0 to (k Gamma 1) and rows are numbered ....

A.S. Acampora, M. Karol, M.G. Hluchyj, "Terabit Lightwave Networks: The Multihop Approach", AT&T Technical Journal, 66, 6 (November/December 1987), 21--34.

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