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WO2007040575A1 - Systeme et procede de reutilisation des longueurs d'ondes dans un reseau optique - Google Patents

Systeme et procede de reutilisation des longueurs d'ondes dans un reseau optique Download PDF

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Publication number
WO2007040575A1
WO2007040575A1 PCT/US2005/046082 US2005046082W WO2007040575A1 WO 2007040575 A1 WO2007040575 A1 WO 2007040575A1 US 2005046082 W US2005046082 W US 2005046082W WO 2007040575 A1 WO2007040575 A1 WO 2007040575A1
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WO
WIPO (PCT)
Prior art keywords
network
sub
nodes
networks
wavelength
Prior art date
Application number
PCT/US2005/046082
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English (en)
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WO2007040575A8 (fr
Inventor
David W. Jenkins
Mark E. Boduch
Original Assignee
Tellabs Operations, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US11/227,308 external-priority patent/US7627245B2/en
Application filed by Tellabs Operations, Inc. filed Critical Tellabs Operations, Inc.
Publication of WO2007040575A1 publication Critical patent/WO2007040575A1/fr
Publication of WO2007040575A8 publication Critical patent/WO2007040575A8/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J14/00—Optical multiplex systems
    • H04J14/02—Wavelength-division multiplex systems
    • H04J14/0227—Operation, administration, maintenance or provisioning [OAMP] of WDM networks, e.g. media access, routing or wavelength allocation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J14/00—Optical multiplex systems
    • H04J14/02—Wavelength-division multiplex systems
    • H04J14/0227—Operation, administration, maintenance or provisioning [OAMP] of WDM networks, e.g. media access, routing or wavelength allocation
    • H04J14/0241—Wavelength allocation for communications one-to-one, e.g. unicasting wavelengths
    • H04J14/0242—Wavelength allocation for communications one-to-one, e.g. unicasting wavelengths in WDM-PON
    • H04J14/0245—Wavelength allocation for communications one-to-one, e.g. unicasting wavelengths in WDM-PON for downstream transmission, e.g. optical line terminal [OLT] to ONU
    • H04J14/0246—Wavelength allocation for communications one-to-one, e.g. unicasting wavelengths in WDM-PON for downstream transmission, e.g. optical line terminal [OLT] to ONU using one wavelength per ONU
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J14/00—Optical multiplex systems
    • H04J14/02—Wavelength-division multiplex systems
    • H04J14/0227—Operation, administration, maintenance or provisioning [OAMP] of WDM networks, e.g. media access, routing or wavelength allocation
    • H04J14/0241—Wavelength allocation for communications one-to-one, e.g. unicasting wavelengths
    • H04J14/0242—Wavelength allocation for communications one-to-one, e.g. unicasting wavelengths in WDM-PON
    • H04J14/0249—Wavelength allocation for communications one-to-one, e.g. unicasting wavelengths in WDM-PON for upstream transmission, e.g. ONU-to-OLT or ONU-to-ONU
    • H04J14/025—Wavelength allocation for communications one-to-one, e.g. unicasting wavelengths in WDM-PON for upstream transmission, e.g. ONU-to-OLT or ONU-to-ONU using one wavelength per ONU, e.g. for transmissions from-ONU-to-OLT or from-ONU-to-ONU
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J14/00—Optical multiplex systems
    • H04J14/02—Wavelength-division multiplex systems
    • H04J14/0278—WDM optical network architectures
    • H04J14/0283—WDM ring architectures
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J14/00—Optical multiplex systems
    • H04J14/02—Wavelength-division multiplex systems
    • H04J14/0278—WDM optical network architectures
    • H04J14/0284—WDM mesh architectures
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J14/00—Optical multiplex systems
    • H04J14/02—Wavelength-division multiplex systems
    • H04J14/0278—WDM optical network architectures
    • H04J14/0286—WDM hierarchical architectures
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J14/00—Optical multiplex systems
    • H04J14/02—Wavelength-division multiplex systems
    • H04J14/0287—Protection in WDM systems
    • H04J14/0289—Optical multiplex section protection
    • H04J14/029—Dedicated protection at the optical multiplex section (1+1)

Definitions

  • Wavelength Division Multiplexing is a method by which single- mode optical fibers are used to carry multiple light waves of different frequencies.
  • WDM Wavelength Division Multiplexing
  • a WDM network many wavelengths are combined in a single fiber, thus increasing the carrying capacity of the fiber.
  • Signals are assigned to specific frequencies of light (wavelengths) within a frequency band.
  • This multiplexing of optical wavelengths is analogous to the way radio stations broadcast on different wavelengths as to not interfere with each other. Because each channel is transmitted on a different wavelength, a desired channel may be selected using a tuner.
  • WDM channels are selected in a similar manner.
  • all wavelengths are transmitted through a fiber, and demultiplexed at a receiving end.
  • the fiber's capacity is an aggregate of the transmitted wavelengths, each wavelength having its own dedicated bandwidth.
  • DWDM Dense Wavelength Division Multiplexing
  • WDM may be used with dedicated protection techniques such as a Unidirectional Path Switched Ring (UPSR) in a Synchronous Optical Network (SONET).
  • UPSR Unidirectional Path Switched Ring
  • SONET Synchronous Optical Network
  • Such a dedicated protection technique uses dual counter-rotating rings dedicated to a particular wavelength. A working wavelength travels in one direction, and a protection wavelength travels in the opposite direction. The working wavelength typically takes a shorter path between the two nodes while the protection wavelength takes a longer path. The frequency of the working and protection wavelengths may be identical, as they travel in opposite directions. Every section of the dual counter-rotating rings are occupied by either the working wavelength or the protection wavelength (a section may be defined as the fibers directly connecting two nodes within a ring). Therefore, the working wavelength and the protection wavelength cannot be used to establish any additional connections between any other two nodes. Additional connections require the use of additional wavelengths.
  • UPSR Unidirectional Path Switched Ring
  • SONET Synchronous Optical Network
  • WDM equipment within a given WDM node can only support a finite number of wavelengths; therefore, there is often an economic benefit associated with limiting the number of wavelengths used when designing a WDM network.
  • An embodiment of the present invention includes a network, or corresponding method, with at least four network nodes that are each coupled to at least three network paths. At least two of the at least three network paths couple the network nodes.
  • the network also includes at least two sub-networks that each include at least two of the network nodes and use at least one wavelength in common with the other sub-network.
  • Another embodiment of the present invention includes a network, or corresponding method, with (i) at least one network node coupled to at least four network paths and (ii) at least two sub-networks each including the at least one network node and using at least one wavelength in common.
  • FIG. 1 is a logical view of a reconfigurable, 2-degree, optical, add/drop node according to an embodiment of the present invention
  • FIG. 2 is a logical view of a reconfigurable, 3-degree, optical, add/drop node according to an embodiment of the present invention
  • FIG. 3 is a physical perspective of a reconfigurable, 2-degree, optical, add/drop node
  • FIG. 4 is a physical perspective of a reconfigurable, 3-degree, optical, add/drop node
  • FIG. 5 is a network diagram of a multi-ring design using 2-degree nodes and 3-degree nodes;
  • FIG. 6 is a block diagram of a drop unit according to an embodiment of the present invention.
  • FIG. 7 is a block diagram of an add unit according to an embodiment of the present invention.
  • FIG. 8 is a block diagram of a 2-degree node with two, reconfigurable, optical interfaces
  • FIG. 9 is a block diagram of a 3-degree node with three, reconfigurable, optical interfaces
  • FIG. 10 is a block diagram of a 4-degree node with four, reconfigurable, optical interfaces
  • FIG. 11 is a network diagram of a single ring network design utilizing 2- degree nodes
  • FIG. 12 is a network diagram of a single ring network design utilizing 2- degree nodes where a fully protected bi-directional connection is established between nodes C and F;
  • FIG. 13 is a network diagram of a network where nodes B, C, D, and F from
  • FIG. 12 are replaced with 3-degree nodes
  • FIG. 14 is a network diagram of a network where nodes B, C, D, and F from FIG. 12 are replaced with 4-degree nodes;
  • FIGS. 15-18 are network diagrams illustrating how multi-degree nodes may be added to an existing, single ring, DWDM network to create additional sub- network rings that reduce the number of wavelengths used for communications in the network.
  • a total number of wavelengths used in a WDM network may be reduced by designing a network using multi-degree nodes that form multiple sub-networks. Isolated sub-networks that do not share common network paths may reuse the same wavelengths used for communications within the other sub-networks.
  • An embodiment of the present invention includes a network, or corresponding method, with at least four network nodes that are each coupled to at least three network paths. At least two of the at least three network paths couple the network nodes.
  • the network also includes at least two sub-networks that each include at least two of the network nodes and use at least one wavelength in common with the other sub-network.
  • the sub-networks may use at least one wavelength, in addition to the at least one wavelength in common, that supports communications between the nodes of different sub-networks.
  • the sub-networks may be ring networks, mesh networks, or a combination thereof.
  • the network may include at least four network paths that couple the network nodes and define a third sub-network. Additional sub-networks may be defined with an addition of an even number of network paths.
  • the network paths may themselves include multiple network nodes or sub-networks.
  • the network nodes may be reconfigurable; that is, they may be used to selectively reconfigure the optical interconnections associated with the network paths. This reconfiguration may be in the optical domain and may be achieved through the use of Reconf ⁇ gurable Optical Add/Drop Multiplexers (ROADMs). Additionally, the nodes of the network may include add/drop ports that are used for adding or dropping wavelengths to and from the network.
  • ROADMs Reconf ⁇ gurable Optical Add/Drop Multiplexers
  • a network path carries a data stream between network nodes and may be a single fiber for uni-directional traffic or multiple fibers for bi-directional communications .
  • FIGS. 1-4 and 6-12 illustrate embodiments of nodes, add/drop multiplexers, and network protection techniques (e.g., Unidirectional Path Switched Ring (UPSR)) useful for understanding aspects of the present invention.
  • UPSR Unidirectional Path Switched Ring
  • FIG. 1 illustrates a logical view of a reconf ⁇ gurable, 2-degree, optical, add/drop node 100 according to an embodiment of the present invention.
  • the node 100 includes two reconfigurable optical interfaces (ROIs).
  • the ROIs are labeled East 110 and West 120 in FIG. 1.
  • Each ROI includes a multi- wavelength input port 130a, 130b and a multi- wavelength output port 140a, 140b.
  • the multi-wavelength ports transport multiple wavelengths over single fibers 150a, 150b and 16Oa 5 160b by using wavelength division multiplexing (WDM) techniques.
  • WDM wavelength division multiplexing
  • add and drop ports add and drop ports
  • each ROI (not shown) are associated with each ROI. Multiple wavelengths may be dropped at a given ROI. When wavelengths. are dropped, each dropped wavelength is placed on an individual fiber 170a, 170b. It should be appreciated that the single line 170a, 170b in FIG. 1 used to show drops may represent multiple individual fibers. When wavelengths are added, each added wavelength is received on an individual fiber 180a, 180b. It should be appreciated that the single line 180a, 180b in FIG. 1 used to show adds may represent multiple individual fibers.
  • a wavelength ( ⁇ ) arriving on the multi-wavelength input port 130a, 130b of a given ROI 110, 120 may be directed to either the associated drop port 170a, 170b or may be passed-through to the multi- wavelength output port 140b, 140a of the other ROI 120, 110.
  • ROIs 210, 220, and 230 are labeled East, West, and North, respectively.
  • a wavelength ( ⁇ ) arriving on the multi-wavelength input port of a given ROI may be directed to either the associated drop port or may be passed-through to the multi-wavelength output ports of either of the two other ROIs, as indicated in FIG. 2.
  • FIG. 3 illustrates a physical perspective of a node 300.
  • the node 300 includes two ROIs 310, 320.
  • the node 300 may be implemented as the node 100 shown in FIG. 1.
  • add units 311 and 321 may be used to add wavelengths to multi- wavelength output ports.
  • these wavelengths can come from either the add ports or from the drop unit 322 of the other ROI 320, as indicated.
  • Drop units 312 and 322 may be used to drop wavelengths to individual fibers of an associated drop port.
  • these wavelengths may come from the multi- wavelength input port associated with the given ROI 310.
  • FIG. 4 illustrates a physical perspective of a node 400.
  • the node 400 includes three ROIs 410, 420, and 430.
  • the node 400 may be implemented as the node 200 shown in FIG. 2 and operate in a similar manner as the 2-degree node 300 described in reference to FIG. 3.
  • FIG. 5 illustrates a multi-ring design 500 using 2-degree nodes and 3-degree nodes.
  • Nodes A 510 and C 530 are 2-degree nodes.
  • Nodes B 520 and D 540 are 3- degree nodes.
  • Ring 1 550, Ring 2 560, and Ring 3 570 there are three distinct rings, referred to as Ring 1 550, Ring 2 560, and Ring 3 570.
  • Ring 1 includes nodes A, B, C, and D.
  • Ring 2 includes nodes A, B 5 and D.
  • Ring 3 includes nodes B, C and D.
  • the rings 550, 560, 570 share some common paths (or ring sections). For instance, Ring 2 and Ring 3 share a path between nodes B and D.
  • FIG. 6 illustrates a drop unit 600 according to an embodiment of the present invention.
  • the drop unit 600 may be implemented as one of the drop units illustrated in FIGS. 3 and 4.
  • the optical directivity element 610 may be used to direct wavelengths (M ⁇ lP) arriving via a fiber 605 on the multi-wavelength input 5 port 607 to its various multi- wavelength output ports 615.
  • the wavelengths exiting the lower multi- wavelength output port 617 of the optical directivity element 610 are sent to a WDM demultiplexer 620.
  • the WDM de-multiplexer 620 de-multiplexes the WDM signal io into its individual wavelengths (S ⁇ DPi - SXDFN) and directs each wavelength to a specific individual fiber. Because there are N possible wavelengths carried within the multi- wavelength ports, the de-multiplexer 620 supports up to N "drop" fibers 630. Wavelengths (MkOFl - MkOFK-I) that are not dropped may be directed via output fibers 640 to one or more of the other multi- wavelength output ports 615 on
  • FIG. 7 illustrates an add unit 700 according to an embodiment of the present invention.
  • the add unit 700 may be implemented as one of the add units illustrated in FIGS. 3 and 4.
  • a set of WDM de-multiplexers 710 (such as an Arrayed Waveguide Grating (AWG)) are used to de-multiplex the wavelengths (M ⁇ lPi - 0 MkIPK) arriving on multi-wavelength input ports 705 into individual wavelengths ( ⁇ l - ⁇ N).
  • the wavelengths are then sent to a set of NK-to-1 optical switches 720. In some embodiments, there is one switch associated with each of the N wavelengths.
  • the source of a given wavelength on a multi- wavelength output port 750 of a WDM multiplexer (MUX) 740 can come from any of the K-I 5 multi-wavelength input ports 705 or from the individual single wavelength add ports 707, as shown.
  • MUX WDM multiplexer
  • FIG. 8 illustrates a 2-degree node 800 with two ROIs 810a, 810b, each including both an add unit 820a, 820b and a drop unit 830a, 830b.
  • FIG. 9 illustrates a 3-degree node 900 with three ROIs 910a, 91 Ob 5 91 Oc, each including both an add unit 920a, 920b, 920c and a drop unit 930a, 930b, 930c.
  • FIG. 10 illustrates a 4-degree node 1000 with four ROIs 1010a, 1010b, 1010c, 101 Od, each including both an add unit 1020a, 1020b, 1020c, 102Od and a drop unit 1030a, 1030b, 1030c, 1030d.
  • FIG. 11 illustrates a single ring network design 1100 utilizing 2-degree nodes 1110a-f.
  • the network 1100 includes dual "counter-rotating" rings 1105a, 1105b. Dual counter rotating rings are used in dedicated protection techniques such as UPSR.
  • a bi-directional connection between two nodes e.g., nodes 1110a and 111Of
  • both a working wavelength and a protection wavelength may be used to establish a fully protected bi-directional connection between the two nodes.
  • the wavelengths of the working and protection wavelengths may be identical.
  • FIG. 12 shows an example network having working and protection wavelengths using the same wavelength, where a fully protected bi-directional connection is established between nodes C and F.
  • the working wavelength ⁇ l W takes a shorter path between the two nodes, while the protection wavelength ⁇ lP takes a longer path.
  • every section of the dual rings are occupied by either the working wavelength or the protection wavelength, where a section may be defined as the two fibers directly connecting two nodes within the ring. Therefore, ⁇ l W and ⁇ lP cannot be used to establish any additional connections between any other two nodes.
  • WDM equipment within a given WDM node can only support a finite number of wavelengths (e.g., 4 wavelengths, 8 wavelengths, or 12 wavelengths, etc.); therefore, there is often an economic benefit associated with better utilizing the wavelengths used when designing a WDM network.
  • the use of multi-degree nodes within a network may help limit the number of wavelengths utilized in constructing a network and its associated connections. As an example, suppose that a network such as the network 1100 shown in FIG. 11 is used to establish fully protected bidirectional connections between every pair of nodes (e.g., using UPSR protection). As illustrated in Table 1 below, a total of fifteen wavelengths are needed to establish all the connections.
  • FIG. 13 illustrates a network 1300 where nodes B 3 C, D, and F from FIG. 12 are replaced with 3 -degree nodes.
  • two "isolated" sub-rings are formed: Sub-Ring 1 1310 and Sub-Ring 3 1330. These sub-rings may be referred to as “isolated sub-rings" because they share no common ring sections.
  • Sub-Ring 3 1330 includes the sub-ring formed by nodes A, B, and C;
  • Sub-Ring 1 1310 includes the sub-ring formed by nodes D, E, and F; and
  • Sub-Ring 2 1320 includes the sub-ring formed by nodes B, C, D, and F.
  • Sub-rings that are isolated from one another may use the same wavelengths to establish connections between the nodes of their associated sub-rings. For instance, in FIG. 13 a connection may be established between nodes D and E on Sub-Ring 1 1310 using wavelength number 1 ( ⁇ l), while this same wavelength number 1 ( ⁇ l) can simultaneously be used to establish a connection between nodes A and B on Sub-Ring 3 1330.
  • a network such as the network 1300 shown in FIG. 13 is used to establish fully protected bidirectional connections between every pair of nodes (e.g., using UPSR protection).
  • Sub-Ring 1 and Sub-Ring 3 use three wavelengths in common, namely wavelength numbers 1, 2, and 3.
  • Sub-Ring 1 1310 and Sub-Ring 3 1330 may use the same wavelengths for communications between their nodes because they are isolated from each other (e.g., wavelength number 1 ( ⁇ l) is used for communications between both nodes A and B, and D and E).
  • Sub-Ring 2 1320 may not use the same wavelengths as Sub-Ring 1 1310 or Sub-Ring 3 1330 because Sub-Ring 2 1320 shares network paths in common with Sub-Ring 1 1310 and Sub-Ring 3 1330 (e.g., the paths between nodes B and C, and the paths between nodes D and F).
  • Sub-Ring 2 1320 must use wavelengths that are not used by either Sub-Ring 1 1310 or Sub-Ring 3 1330 (e.g., wavelength number 7 ( ⁇ 7) is used for communications between nodes B and D).
  • Communications between nodes of different sub-rings i.e., communications along a main outer ring 1340
  • wavelengths that are not used by any of the sub- rings e.g., wavelength number 4 ( ⁇ 4) is used for communications between nodes A and D).
  • FIG. 14 illustrates a network 1400 where nodes B, C, D, and F from FIG. 12 are replaced with 4-degree nodes with the extra degrees used to create two additional links using fiber pairs directed from node B to node C and from node D to node F.
  • three "isolated" sub-rings are formed: Sub-Ring 1 1410, Sub- Ring 2 1420, and Sub-Ring 3 1430.
  • Sub-Ring 3 1430 includes the sub- ring formed by nodes A, B, and C using vertical fiber paths T and V.
  • Sub-Ring 2 1420 includes a sub-ring formed by nodes B, C, D, and F using vertical fiber paths W and X.
  • Sub-Ring 1 1410 includes a sub-ring formed by nodes D, E, and F using vertical fiber paths Y and Z.
  • the number of wavelengths may be reduced by utilizing the four 4-degree nodes
  • a network such as the network 1400 shown in FIG. 14 is used to establish fully protected bidirectional connections between every pair of nodes (e.g., using UPSR protection).
  • UPSR protection e.g., UPSR protection
  • Table 3 a total of nine wavelengths may be used to establish all the connections. Therefore, six wavelengths are saved by using the 4-degree nodes shown in FIG. 14 (as compared to using only 2-degree nodes).
  • Sub-Ring 1, Sub-Ring 2, and Sub-Ring 3 use three wavelengths in common, namely wavelength numbers 1, 2, and 3.
  • each sub-ring is isolated from the other sub-rings, the same wavelengths may be used in each of the sub-rings (e.g., wavelength number 1 ( ⁇ l) may be used for communications between nodes A and B, nodes B and D, and nodes D and E).
  • Sub-Ring 2 1420 uses an additional wavelength because it includes four nodes (e.g., wavelength number 4 ( ⁇ 4) may be used for communications between nodes C and F).
  • IA can be reused in sub-ring 3 in order to transport additional traffic between two nodes on sub-ring 3.
  • ⁇ 4 can be reused in sub-ring 1 in order to transport additional traffic between two nodes on sub-ring 1.
  • Communications between nodes of different sub-rings must use wavelengths that are not used by any of the sub-rings (e.g., wavelength number 5 ( ⁇ 5) is used for communications between nodes A and E).
  • Additional isolated sub-networks may be created by adding to the network 1400 an even number of paths that couple at least two of the multi-degree nodes. For example, in FIG. 14, an additional isolated sub-ring may be created with an addition of two paths that couple any two of the 4-degree nodes. Both of the newly coupled nodes thus become 6-degree nodes.
  • FIGS. 15-18 illustrate how multi-degree nodes may be added to an existing, single ring, DWDM network to create additional sub-ring networks to reduce the number of wavelengths needed for communications in the network.
  • FIG. 15 is an illustration of an existing, single ring, DWDM network 1500 containing nodes A-L. Many wavelengths are needed for communications between the nodes.
  • a thick dashed line illustrates an exemplary ring 1510 within the network.
  • FIG. 16 illustrates a designation 1610, 1620, 1630 and 1640 of nodes C, E, I 5 and K, respectively, in Ring 1 that are replaced with 4-degree nodes
  • FIG. 17 illustrates an addition of "cut-through" fibers 1710, 1720 connecting the new 4-degree nodes C, E, I, and K. Two fiber pairs may be used for each cut- through to prevent wavelength blocking by creating isolated sub-networks. The addition of the cut-throughs creates three, new, isolated sub-network rings 1730, 1740, 1750.
  • FIG. 18 is a perspective of the resulting DWDM network that contains a total of four rings. Rings 1-3 1730, 1740, 1750 are the newly created rings, while Ring 4 1510 is the original. Network traffic may be routed so that each demand traverses only one ring. This reduces the number of wavelengths that are needed for communications in the network.

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  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Optical Communication System (AREA)
  • Small-Scale Networks (AREA)

Abstract

L'invention concerne une structure de réseau permettant de réduire le nombre de longueurs d'onde nécessaires pour assurer les communications dans un réseau à multiplexage en longueur d'onde (WDM). Les longueurs d'onde sont réutilisées dans des sous-réseaux qui ne possèdent pas de chemins communs, et permettent ainsi de réduire les coûts en équipements WDM nécessaires pour la prise en charge des communications dans le réseau.
PCT/US2005/046082 2005-09-15 2005-12-20 Systeme et procede de reutilisation des longueurs d'ondes dans un reseau optique WO2007040575A1 (fr)

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US11/227,308 2005-09-15
US11/227,308 US7627245B2 (en) 2004-12-16 2005-09-15 System and method for re-using wavelengths in an optical network

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Citations (3)

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Publication number Priority date Publication date Assignee Title
US20030156317A1 (en) * 2000-03-10 2003-08-21 Ruhl Frank Friedrich Communications network architecture
WO2003104849A2 (fr) * 2002-05-02 2003-12-18 Fujitsu Network Communications, Inc. Reseau en fibre optique comportant des noeuds et procede correspondant
US20040208573A1 (en) * 2002-01-09 2004-10-21 Fujitsu Networks Communications, Inc. Interconnecting nodes in an optical communication system

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Publication number Priority date Publication date Assignee Title
US20030156317A1 (en) * 2000-03-10 2003-08-21 Ruhl Frank Friedrich Communications network architecture
US20040208573A1 (en) * 2002-01-09 2004-10-21 Fujitsu Networks Communications, Inc. Interconnecting nodes in an optical communication system
WO2003104849A2 (fr) * 2002-05-02 2003-12-18 Fujitsu Network Communications, Inc. Reseau en fibre optique comportant des noeuds et procede correspondant

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Title
LEE A. S. T.; HUNTER D. K.: "Heuristic for Setting up a Stack of WDM Rings with Wavelength Reuse", JOURNAL OF LIGHTWAVE TECHNOLOGY, vol. 18, no. 4, April 2000 (2000-04-01), IEEE, pages 521 - 529, XP002378138 *
MEDOVA E A: "Optimal design of reconfigurable ring multiwavelength networks", THE INSTITUTION OF ELECTRICAL ENGINEERS, 1993, IEE, Savoy Place, London WC2R UK, pages 9 - 1, XP006519291 *
WUTTISITTIKULKIJ L ET AL: "Design of a WDM network using a multiple ring approach", GLOBAL TELECOMMUNICATIONS CONFERENCE, 1997. GLOBECOM '97., IEEE PHOENIX, AZ, USA 3-8 NOV. 1997, NEW YORK, NY, USA,IEEE, US, vol. 1, 3 November 1997 (1997-11-03), pages 551 - 555, XP010254659, ISBN: 0-7803-4198-8 *

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