This paper introduces a family of bidirectional multi-fibre passive photonic ring architectures that may serve as a high-capacity network backbone for supporting next-generation data-centric services. We introduce a novel dual-router node design that avoids several non-ideal routing phenomena typically associated with passive networks based on cyclic graphs. Our design also achieves the requisite single-hop full-mesh connectivity needed for arbitrary node-to-node communications. A ring enlargement strategy is presented that allows this architecture to scale across a wide range of networking domains. A medium access protocol will also briefly elaborated

Harle, D.A.

Lee, A.S.T.

Tachtatzis, C.

English

Name not available

A novel optical passive router ring architecture using MAGNet protocol

University of Strathclyde Institutional Repository

Strathprints Institutional RepositoryTachtatzis, C. and Lee, A.S.T. and Harle, D.A. (2003) A novel optical passive router ring architectureusing MAGNet protocol. In: Conference on Heterogenous Networks (HETNETs03), 2003-07-21 -2003-07-24, Ilkley.Strathprints is designed to allow users to access the research output of the University of Strathclyde.Copyright c© and Moral Rights for the papers on this site are retained by the individual authorsand/or other copyright owners. You may not engage in further distribution of the material for anyprofitmaking activities or any commercial gain. You may freely distribute both the url (http://strathprints.strath.ac.uk/) and the content of this paper for research or study, educational, ornot-for-profit purposes without prior permission or charge.Any correspondence concerning this service should be sent to Strathprints administrator:mailto:strathprints@strath.ac.ukhttp://strathprints.strath.ac.uk/P1/1   A Novel Optical Passive Router Ring Architecture Using MAGNet Protocol   Christos Tachtatzis, Andrew S. T. Lee, David Harle {ctachtatzis, a.lee, d.harle}@eee.strath.ac.uk Broadband and Optical Networks (BON) Research Group Dept. of Electronic and Electrical Engineering University of Strathclyde, Glasgow G1 1XW, UK   Abstract  This paper introduces a family of bidirectional multi-fibre passive photonic ring architectures that may serve as a high-capacity network backbone for supporting next-generation data-centric services. We introduce a novel dual-router node design that avoids several non-ideal routing phenomena typically associated with passive networks based on cyclic graphs. Our design also achieves the requisite single-hop full-mesh connectivity needed for arbitrary node-to-node communications. A ring enlargement strategy is presented that allows this architecture to scale across a wide range of networking domains. A medium access protocol will also briefly elaborated.  Keywords : Optical Networks, Local-Area Networks, Metropolitan-Area Networks, Wavelength Routing, Clustered Computing  1 Introduction The ongoing commodisation of computing and storage technologies will bring about the emergence of a network-wide computational environment. Prominent indicators of this trend include the development of commodity ad-hoc clustered computing networks based on the open-source Linux operating system [1]. There is also active research activity in the development of "computational grids" - a distributed computing environment catering initially for those complex scientific applications with significant computation, bandwidth and storage requirements [2]. This paper presents a novel low-cost passive ring architecture based on recent research developments in passive componentry and athermal active optical devices stemming from the multi-university collaborative PHOTON project [3]. It is envisaged that this type of network architecture may form the basis of a networking backbone for interconnecting multiple clustered computing sites and also for supporting high bandwidth services from the emergent data-centric traffic environment.  2 Passive Photonic Ring Architecture The key functional device employed in the ring architecture is called a passive wavelength router and realized in silica using a 2D integrated optics (2DIO) platform [4]. This fabrication approach enables compact designs for passive optical devices and the ”folded” construction of the 2DIO device is depicted in Figure 1(a). The passive router is a multi-port device (Figure 1(b)) and its fixed routing function is to direct wavelengths belonging to any input port, i, to a specific output port, j. The routing function is given by ( ) { } [ ]MjiMij ,1,,,1mod2 Î+-+= ll , where M is the number of ports and l denotes the input wavelength. The interconnection of passive routers in cyclic graphs, i.e. ring and mesh topologies, may exhibit several non-ideal routing phenomena: self-loops, stranded wavelength loops of capacity and loop-backs. We introduce a novel dual-router node design (Figure 2(c)) that avoids the aforementioned phenomena and achieves the requisite single-hop full-mesh connectivity for facilitating arbitrary node-to-node communications. Given the expected loss along the passive router cascade, our architecture specifies a multihop routing strategy for the periodic regeneration of circuitous lightpaths and improving traffic loading.  2.1 Network Structure The node interconnection pattern in a ring of N nodes is given by: P1/2 ( ) ( ) 1mod2,,1,02mod22)AR()DR()1modDR()AR()1mod2DR()AR()AR(+-+=ïîïíì®®=úúúúûúêêêêëê÷øöçèæ -+¢++-+ MMjiijijMMMjnnNnnNNnnn where AR(n) and DR(n) denotes add and drop router belonging to node n respectively. The set of all valid intra-router unidirectional transit connections is given by: MjMMjMjC nnn ,...,1,mod22 )DR()DR()DR(=þýüîíì÷øöçèæ -+-®=  We choose a subset CT Î (Figure 1(d)) for creating the desired network architecture and the resultant unconnected ports serve as add and drop ports. For a 8-node ring (N=M=8) we choose different transit connections for a subset of nodes in sequence I:{2-4, 3-3, 4-2, 5-1}, II:{1-5, 2-4, 4-2, 7-7}, III:{5-1, 6-8, 7-7, 8-6} and IV:{1-5, 3-3, 6-8, 8-6} where I, II, III and IV label the different nodes types in sequence (Figure 2(e)). This sequence specifies a ring segment, S = {I, II, III, IV} and the 8-node ring represents a concatenation of two ring segments (Figure 2(e)). This results in the following fixed distribution of lightpaths emanating from every node along the ring and for each of the two ring directions: 8 lightpaths over one link, 2 lightpaths over 2 links, 4 lightpaths over 3 links and 2 lightpaths over 4 links. Since the ring has an even number of nodes, there are 4 lightpaths using 4 links between any diametrically opposite node pairs. Analogous network constructions have also been determined for 4-node and 6-node rings.  2.2 Modular Ring Enlargement Concept Larger rings may be created using a modular enlargement scheme. For example ring R = {S, S, ...} for ring sizes N (N mod 4=0, N ³ 8) (Figure 2(f)). Connections traversing more than one ring segment will be transported as a semi-lightpath1. A non-modular enlargement of rings is also possible using pre-specified node types. However, it can be shown that undesirable routing effects may result for certain cases.  3 Node Architecture and Medium Access A medium access protocol called Medium Access for Grid Networks (MAGNet) is designed for this type of passive ring architecture. The node architecture adopts either a FTFR2 or TTFR structure (Figure 2) – the transmitter architecture is based on an array of fixed-wavelength lasers or a limited array of agile-wavelength lasers for every add port. A wavelength on every drop port is received independently using an array of fixed-wavelength receivers. Data packets entering the network is given a fixed port and wavelength assignment based on its destination and mapped onto a frame structure depicted in Figure 3. Given the passive forwarding nature of the network, wavelength routing is entirely deterministic. Each wavelength operates at the 10 Gbps line rate and we examine routing policies for supporting a multi-priority traffic environment. We conclude that tunable nodes offer comparable performance to those designs featuring fixed wavelength transmitters.  Acknowledgements The work is supported by EPSRC grant GR/M/98883 on ’Physical Layer High-Speed Optoelectronics for Tomorrow’s Optical Networks’.  References [1] Beowulf Cluster Site, http://www.beowulf.org/ [2] "New Science from High-Performance Computing", Phil. Trans. Royal Society of London A, Vol. 360, No. 1795, June 2002 [3] PHOTON Project Site, http://www.photon-project.org.uk/ [4] ”Compact integrated silica wavelength filters”, Morgan C., Yu S., Penty R., White I., IEEE Photonics Tech. Letters, Vol. 14, No. 9, Sept. 2002, pp.1303-1305                                                      1 A semi-lightpath is defined as the virtual connection that is created from a concatenation of more than one wavelength-continuous lightpath. Each constituent lightpath is electrically terminated, i.e. the virtual connection may undergo more than one optoelectronic wavelength conversion.  2 FTFR – Fixed Transmitter, Fixed Receiver, TTFR – Tunable Transmitter, Fixed Receiver P1/3 1 2 3 4 5 6 7 81 2 3 4 5 6 7 81 2 3 4 5 6 7 81 2 3 4 5 6 7 8DROPREVERSEfrom AR(n+1)FORWARDfrom AR(n-1)TRANSITFORWARDto DR(n+1)REVERSEto DR(n-1)DROP ROUTER DR(n)ADD ROUTER AR(n)ADD(a)(b)(c)f = forward wavelengthsr = reverse wavelengthsr f f f f r r rr r f f f f r rr r r f f f f rr r r r f f f ff r r r r f f ff f r r r r f ff f f r r r r ff f f f f r r rf r r r r f f fr r r r f f f fr r r f f f f rr r f f f f r rr f f f f r r rf f f f r r r rf f f r r r r ff f r r r r f f1234567812345678(d)AR(1)DR(1)I II III IVAR(2)DR(2) AR(3)DR(3) AR(4)DR(4) AR(5)DR(5)I II III IVAR(6)DR(6) AR(7)DR(7) AR(8)DR(8)SS S S S(e)(f)O1O2O3O4I1I2I3I41111 4 3 2 12222 4 3 2 13333 4 3 2 14444 4 3 2 12341 4 3 2 13412 4 3 2 14123 4 3 2 11234 4 3 2 1i jM = 4diffractiongratingparabolicmirrorinputwaveguidesoutputwaveguides  Figure 1: (a) plan view of integrated passive router layout; (b) routing function; (c) dual-router node design; (d) intra-router transit pattern; (e) 8-node MAGNet ring; (f) 16-node MAGNet ring demonstrating modular enlargement Priority QueuesApplicationsReceive QueuesTB: Transit BufferHB: Transmit Holding BufferRB: Receive BufferNode ControllerLookup TableHBE/OHBE/OHBE/OHBE/OHBE/OHBE/OHBE/OHBE/ORBO/ERBO/ERBO/ERBO/ERBO/ERBO/ERBO/ERBO/ETBTBTBTBTBTBTBTBTransitSchedulerFigure 2: FTFR node architecture  Pream ble(8 bytes)Start F ram eDelim iter(1 byte)Control B its(1 byte)Source Node(1 byte)DestinationNode(1 byte)Length / Type(2-bytes)C RC32(4 bytes)Payload (40-1500 bytes)Type ofpacket(2 b its)Priority  B its(3 bits)ReservedBits(3  bits)   Figure 3: MAGNet frame structure 

[1] Beowulf Cluster Site, http://www.beowulf.org/ [2] &quot;New Science from High-Performance Computing&quot;,

i jM = 4 diffraction grating parabolic mirror input waveguides output waveguides

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A novel optical passive router ring architecture using MAGNet protocol

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