JP5831681B2 - Wavelength path setting method and apparatus in wavelength division multiplexing communication network - Google Patents

Description

  The present invention relates to a wavelength division multiplexing communication network configured by connecting a plurality of node devices in which an optical switch unit and a packet switch unit are integrated, and more particularly to a wavelength path setting method and device thereof.

  Due to the progress of high-definition video services, the rapid increase in communication traffic and the increase in power consumption of carrier grade IP routers have become problems. In order to solve this problem, a method of offloading routing processing that is not involved in the transport function from the IP router has been studied. Specifically, a low layer packet transfer function such as MPLS (Multi Protocol Labeling Switch), Ethernet (Ethernet; registered trademark, hereinafter the same), an OTN (Optical Transport Network) frame, and a wavelength path in a wavelength multiplexing communication network A method responsible for packet transfer processing has been studied and its effectiveness has been shown. In particular, the offloading of packet transfer to the wavelength path remains as a wavelength path without performing conversion between electrical and optical signals (EO / OE: Electrical-to-Optical / Optical-to-Electrical) at the relay node. An optical cut-through passing through the node can be realized. As a result, the electrical processing of the OE / EO and the packet / frame switch can be eliminated, so that the power consumption can be greatly reduced, and it is considered promising particularly from the viewpoint of power saving.

  On the other hand, ROADM (Reconfigurable Optical Add / Drop Multiplexing) devices that perform wavelength-controllable demultiplexing have been introduced in the domestic and foreign fields as node devices of wavelength multiplexing communication networks. Large-scale communication carriers realize close function linkage between wavelength path and packet transfer by integrating ROADM / WXC (WXC: Wavelength Crossconnect) function that configures the network with wavelength path and packet transfer functions such as MPLS and Ethernet. The aim is to reduce equipment and management costs.

  In addition, as seen in the development of data centers and HPC (High Performance Computing), a network that allows extremely large volumes of traffic to be exchanged between servers and computers has emerged, although it is a local network with a relatively limited geographical spread. Even in such application areas, studies are being made on the introduction of WDM and wavelength path networks that dramatically expand the capacity per link.

  As described above, in order to expand the transport capacity, it is necessary to realize a node device that hybridizes packet transfer and wavelength path ADM / XC on the premise of accommodating a packet at the client interface. A network, a node device, and a control method for realizing an efficient offload to the network are actively studied.

  For example, Patent Document 1 discloses a node device and a cut-through path setting method for reducing electrical routing processing by setting a cut-through path of an optical signal so as to bypass a packet processing device having a heavy processing load. ing. More specifically, in an apparatus that combines an OADM function and a packet processing function, an input port that is the main cause of packet concentration at an output port is specified, and an optical signal at the input port bypasses the packet processing apparatus. Set the cut-through path.

JP 2005-277951 A

  However, the optical path setting method disclosed in Patent Document 1 has several problems to be solved because the traffic amount is monitored and the optical cut-through path setting control is performed for each port. Hereinafter, the main problems will be described by taking a network including the nodes N1 to N5 shown in FIG. 1 as an example.

  As shown in FIG. 1A, in the node N2, a flow F1 that transits the own node among a plurality of packet flows received from the adjacent upstream node N3 and a flow F2 that drops on the own node are mixed. Since the traffic volume is monitored and mapped to the wavelength path on a port basis, only the transiting packet flow cannot be cut through. Therefore, the most efficient cut-through path cannot be set according to the flow status, and the improvement of the wavelength utilization efficiency and the reduction of the packet processing load cannot be achieved sufficiently.

  As shown in FIG. 1B, in order to specify the switching node in units of ports, the node N2 determines that the traffic amount from the adjacent upstream node N3 is large, and sets an optical path between the node N3 and the node N1. The wavelength utilization efficiency is lowered due to the setting. This is because in this case, an optical path should be set between the node N4 and the node N1 in order to offload a flow having a large bandwidth that is a cause of congestion.

  As shown in FIG. 1C, since only a means for providing a traffic amount monitor and optical cut-through for each port to the relay node is provided, packet flow communication beyond the wavelength path band and between adjacent nodes are provided. I cannot set the wavelength path.

  Furthermore, since there is no means for merging into a wavelength path that has already been set for the occurrence of a new packet flow that exceeds the traffic volume threshold, the wavelength utilization efficiency of the wavelength path decreases. In addition, since the bandwidth (traffic amount) is monitored on a port basis and wavelength path mapping is performed at the upstream node adjacent to the receiving port where the traffic amount exceeds the threshold value, the port utilization efficiency of the packet switch decreases.

  Accordingly, an object of the present invention is to provide a wavelength path setting method and apparatus capable of solving the above-described problems and improving the wavelength utilization efficiency and reducing the packet processing load in the wavelength division multiplexing communication network.

A wavelength path setting device according to the present invention is a wavelength path setting device in an optical wavelength division multiplexing network in which a plurality of node devices are connected by an optical transmission line, and each node device has a configuration in which an optical switch unit and a packet switch unit are integrated. Each node device has a congestion determination means for determining the presence or absence of congestion by monitoring the traffic amount of each communication packet in a flow unit, and for eliminating the congestion based on the congestion occurrence information from the node device. setting at least one wavelength path, have a, and a control means for at least one packet flow are involved switching to the wavelength path to the congestion, said control means, the top node first node to detect the congestion And at least one packet flow involved in the congestion is identified, and the identified parameter is transmitted to a downstream node. The congestion state of the packet flow is sequentially confirmed, and the downstream node that is confirmed as having no congestion is set as the rear-end node of the packet flow, thereby detecting the congestion node section where the congestion occurs based on the congestion occurrence information, The node device in the congestion node section is controlled to set the at least one wavelength path and switch the at least one packet flow to the wavelength path .

The wavelength path setting method according to the present invention is a wavelength path setting method in an optical wavelength division multiplexing network in which a plurality of node devices are connected by an optical transmission line, and each node device has a configuration in which an optical switch unit and a packet switch unit are integrated. Each node device determines the presence or absence of congestion by monitoring the amount of traffic in the communication packet flow unit, and the control means starts the node that first detected congestion based on the congestion occurrence information from the node device. Identify at least one packet flow involved in the congestion, sequentially check the congestion state of the identified packet flow with respect to the downstream node, and select the downstream node confirmed as having no congestion By setting it as the rear-end node of the packet flow, the congestion node section where the congestion occurs is detected, and the congestion node section And it controls the node device, wherein the set of at least one wavelength path switching to the at least one packet flow the wavelength path, characterized in that.

  According to the present invention, it is possible to improve the wavelength utilization efficiency and reduce the packet processing load in the wavelength division multiplexing communication network.

FIGS. 1A to 1C are network diagrams for explaining some problems of cut-through path setting control according to a known example. FIG. 2 is a block diagram showing a functional configuration of the node device according to the first embodiment of the present invention. 3A shows an example of a packet switch port / optical port correspondence table used in this embodiment, and FIG. 3B shows an example of a packet transfer table (FDB) used in this embodiment. FIG. 3C is a diagram showing an example of a packet switch port bandwidth monitor table used in this embodiment, and FIG. 3D is a schematic diagram for explaining the basic operation of the node device according to this embodiment. It is. FIG. 4 is a schematic diagram showing a setting example of a packet switch port / optical port correspondence table showing a correspondence relationship between packet switch ports and optical ports in an example of a network to which the node device according to the present embodiment is applied. FIG. 5 is a block diagram showing a schematic configuration of a wavelength division multiplexing network according to the first embodiment of the present invention. FIG. 6 is a schematic diagram showing an example of a table of each node when congestion is detected in the network shown in FIG. FIG. 7 is a flowchart for explaining the optical path setting operation of each node in the network shown in FIG. FIG. 8 is a schematic diagram showing an example of a table of each node when setting an optical path in the network shown in FIG. FIG. 9 is a flowchart for explaining an optical path setting control operation in the network shown in FIG. FIG. 10A is a block diagram showing a schematic configuration of a first example of a wavelength division multiplexing network according to the second embodiment of the present invention, and FIG. 10B shows a wavelength division multiplexing communication network according to the second embodiment of the present invention. It is a block diagram which shows the schematic structure of a 2nd example. FIG. 11 is a flowchart for explaining the optical path setting control operation of each node in the network shown in FIG. FIG. 12 is a flowchart for explaining an optical path setting operation in the network shown in FIG. FIG. 13 is a block diagram showing a functional configuration of a node device according to the second embodiment of the present invention. FIG. 14 is a block diagram showing an example of a network using the node device shown in FIG.

  According to the present invention, in a wavelength division multiplexing communication network in which a plurality of node devices are connected, each node device has a configuration in which an optical switch unit and a packet switch unit are integrated, and each node device has a communication packet flow. Monitors the traffic volume in units, sets a wavelength path so that congestion is eliminated when congestion occurs, and switches at least one flow to this wavelength path, thereby improving wavelength utilization efficiency and packet processing load To achieve a reduction in Hereinafter, node devices and network systems according to embodiments and examples of the present invention will be described in detail with reference to the drawings.

1. In FIG. 2, the node device 10 according to the first embodiment of the present invention includes an OADM / OXC unit 11 having an optical switch function, a packet / frame transfer unit 12 having a packet switch function, an optical switch control and a wavelength control. And a node control unit 13 that performs packet switch control, the node control unit 13 may include an optical path setting control unit 14 that performs cooperative control of wavelength paths and packet flows. A similar function can be realized by arranging the optical path setting control unit 14 in a network and transmitting / receiving control signals to / from each node device. Hereinafter, each functional component will be described in detail.

  The OADM / OXC unit 11 includes wavelength separation filters 101.1 to 101.N connected to N input ports IN # 1 to IN # N, respectively. N and optical switches 102.1 to 102. L and wavelength multiplexing filters 103.1 to 103.N connected to the N output ports OUT # 1 to OUT # N, respectively. N, and optical switches 102.1 to 102. L and optical switches 104.1 connected to one input port of each of L, and optical switches 102.1 to 102. M EO / OE units 105.1 that perform conversion between optical signals and electrical signals between the optical switch 104.2 connected to one output port of L and the packet / frame transfer unit 12 ~ 105. M. The M input ports of the optical switch 104.1 are respectively EO / OE units 105.1 to 105. The M output ports of the optical switch 104.2 are connected to the outputs of the M, and the EO / OE units 105.1 to 105.105 respectively. Connected to the input of M.

  The wavelength division multiplexed signals input from the optical fiber transmission lines through the input ports IN # 1 to IN # N are respectively wavelength separation filters 101.1 to 101.101. N are respectively wavelength-separated and the wavelength-separated input optical signal and the optical signal output from the optical switch 104.1 are the optical switches 102.1 to 102.n. L is output to an arbitrary wavelength multiplexing filter or optical switch 104.2. As will be described later, an optical signal having a wavelength that cuts through the node device 10 is not transferred to the optical switch 104.2 but is directly transferred to the wavelength multiplexing filter of an appropriate output port. An optical signal having a wavelength dropped by the node device 10 is transferred to an appropriate EO / OE section through the optical switch 104.2.

  The packet / frame transfer unit 12 includes EO / OE units 105.1 to 105. M data link / physical layer (DL / PHY) processing units 106.1 to 106 provided corresponding to M respectively. M and the PSW ports # 1 to #M, DL / PHY processing units 106.1 to 106. And a packet switch 107 to which M is connected. The DL / PHY processing unit 106 constructs a frame as needed for physical layer processing necessary for packet transmission / reception, maps the packet to a payload, sends the packet to the OE / EO unit, and transmits the frame received from the OE / EO unit. It has a function of demapping packets from the payload. The packet switch 107 includes DL / PHY processing units 106.1 to 106. A transmission port is determined based on header information such as a transmission destination address and a transmission source address of the packet received from M and transferred. The packet switch 107 also has a function of monitoring an input / output band for each flow identified based on packet header information such as a transmission destination address and a transmission source address.

  The node control unit 13 includes a packet flow control management unit 108 that controls and manages the packet flow, an optical switch control of the OADM / OXC unit 11 and an OADM / OXC control unit 109 that performs transmission wavelength setting control of the OE / EO unit, Have.

  The optical path setting control unit 14 controls the packet flow control management unit 108 and the OADM / OXC control unit 109 based on the traffic amount information in units of flows input from the packet flow control management unit 108, and performs wavelength path setting control and Performs packet flow switching control in coordination. This linkage control is performed using an information table described below.

  The PSW / optical port correspondence table 201 shown in FIG. 3A stores the correspondence between the port numbers allocated to the packet switch 107 and the optical port numbers allocated to the node device 10. Here, it is shown that PSW port # 1 and optical port # 1 are associated with an optical signal with wavelength λ1, and PSW port # 2 and optical port # 2 are associated with an optical signal with wavelength λ1.

  The packet forwarding table (FDB) 202 shown in FIG. 3B manages the input / output optical port numbers and bandwidth monitor information for each flow identified based on packet header information such as a transmission destination address and a transmission source address. It is a table to do. Here, the packet flow # 1 is input from the optical port IN # 1, the flow bandwidth is X, the packet flow # 2 is also input from the optical port IN # 1, and is output from the optical port OUT # 2. The flow bandwidth is Y. Note that it may be shared with the lookup table function required for the packet transfer function of the packet switch 107.

  A PSW port bandwidth monitor table 203 shown in FIG. 3C is a table for managing traffic volume information for each input / output port of the packet switch 107 based on information in the packet transfer table 202. The packet flow control management unit 108 can determine whether or not the bandwidth for each flow exceeds a predetermined threshold by referring to the PSW port bandwidth monitor table 203. Note that these information tables 201 to 203 are only required to be provided in the node apparatus 10 and there are no restrictions on the arrangement location.

  As shown in FIG. 3D, the wavelength path corresponding to the table information shown in FIGS. 3A to 3C is the wavelength path 301 of the wavelength λ1, and the packet flows # 1 and # 2 are respectively Packet flows 302 and 303. For example, referring to FIG. 2, the packet flow 302 includes an input optical port IN # 1, a wavelength separation filter 101.1, an optical switch 102.1, an optical switch 104.2, an OE / EO unit 105.1, a DL / The data is transferred to the destination client IF through the PHY processing unit 106.1 and the PSW port # 1 of the packet switch 107. The packet flow 303 includes an input optical port IN # 1, a wavelength separation filter 101.1, an optical switch 102.1, an optical switch 104.2, an OE / EO unit 105.1, a DL / PHY processing unit 106.1, PSW port # 1, PSW port # 2, DL / PHY processing unit 106.2, OE / EO unit 105.2, optical switch 104.1, optical switch 102.1, wavelength multiplexing filter 103.2, packet switch 107, And, it is transferred through the output optical port OUT # 2.

  The function of the node control unit 13 illustrated in FIG. 2 can be realized by executing a program stored in a memory on a program control processor such as a CPU (Central Processing Unit) provided in the node device 10. . The function of the optical path setting control unit 14 may also be realized by executing a program stored in the memory on the program control processor of the node device, or may be realized by the optical path setting control unit 14 provided in the network. You may implement | achieve by executing a program similarly on a program control processor.

2. Initial Setting Hereinafter, the optical path setting control method according to the present embodiment will be described in detail by taking as an example a network in which a plurality of node devices 10 shown in FIG. 2 are connected through an optical fiber transmission line in a linear topology. However, the linear topology is an example, and the present invention is not limited to this network configuration.

  As shown in FIG. 4, in a network in which nodes N1 to N5 are configured in a linear topology, each node is assumed to have the same configuration as the node device 10 shown in FIG. Hereinafter, blocks having the same function use the same reference numbers and are distinguished by node symbols following the reference numbers.

  First, in order to establish connection between the packet switches of all the nodes N1 to N5 in the network with the packet switches of the adjacent nodes at the beginning of the network construction, the PSW / optical port correspondence table of each node is shown in FIG. Is set as follows. That is, in the node N5, the correspondence between the PSW port # 2 of the packet switch 107 (N5) and the output optical port OUT # 2 is set by the PSW / optical port correspondence table 201 (N5). In the node N4, the correspondence between the PSW port # 1 of the packet switch 107 (N4) and the input optical port IN # 1 is set by the PSW / optical port correspondence table 201 (N4), and the PSW port # 2 and the input optical port OUT # are set. 2 is set. The other nodes N3 and N2 are set in the same manner as the node 4. In the node N1, the correspondence between the PSW port # 1 of the packet switch 107 (N1) and the input optical port IN # 1 is set by the PSW / optical port correspondence table 201 (N1). Thus, the connection between the packet switches from the node N5 to the node N1 is established.

3. First Embodiment As shown in FIG. 5, in a network according to a first embodiment of the present invention, nodes N1 to N5 are configured in a linear topology, and each node has the same configuration as the node device 10 shown in FIG. However, the optical path setting control unit 14 is provided separately from each node, and transmits and receives control signals to and from each node, thereby enabling setting of a wavelength path and switching of a packet flow to a wavelength path, which will be described later. Hereinafter, the reference number of the optical path setting control unit 14 in the present embodiment is assumed to be “14a”. As described above, the linear topology shown in FIG. 5 is an example, and the present invention is not limited to this network configuration.

3.1) Congestion Detection As shown in FIG. 6, the packet flow # 1 of the node N5 and the transmission destination of the node N1, the packet flow # 2 of the transmission source of the node N4 and the transmission destination of the node N1, and the transmission source Assume that there is a packet flow # 3 having a node N2 and a transmission destination of the node N1, respectively. In this state, since the PSW / optical port correspondence table 201 of each node is the same as that in FIG. 4, FIG. 6 shows a packet transfer table (FDB) 202 and a PSW port bandwidth monitor table 203 in each node.

  Here, assuming that the traffic amount of the flow # 2 has increased in the node N4, the PSW port bandwidth monitor 203 (N4) of the node N4 has the bandwidth X of the flow # 1 and the flow # 2 of the output monitor of the PSW port # 2. The occurrence of congestion is detected when the total value X + Y of the band Y exceeds a preset threshold value. The occurrence of congestion is notified to the optical path setting control unit 14a. Similarly, congestion is detected at the input / output of the nodes N3 and N2 where the packet flows # 1 and # 2 are transiting, and the input of the node N1 where the packet flows # 1 and # 2 are terminated (dropped). The setting control unit 14a is notified.

  When congestion is detected in this way, the optical path setting control unit 14a controls wavelength path setting and flow switching in the following procedure. Hereinafter, the wavelength path setting operation and the flow switching operation will be described in detail with reference to FIGS.

3.2) Wavelength path setting and flow switching operation As shown in FIG. 7, each of the nodes N1 to N4 confirms the presence or absence of congestion, and when congestion is detected, the detected congestion information and free resource information of the own node are optically transmitted. Notify the path setting control unit 14a. Further, in the nodes other than the destination node N1, the congestion state of the downstream node is inquired to the optical path setting control unit 14a and confirmed. The optical path setting control unit 14a collects congestion information and vacant wavelength information from each node (step 401), and makes a response to the congestion state inquiry of the downstream node from each node (step 402). The optical path setting control unit 14a determines a wavelength (λ2) that can be commonly used by each node from the node (first node, here, node N4) where congestion is first detected to the rear end node (here, node N1). (Step 403). Subsequently, the optical path setting control unit 14a determines a wavelength path to be set based on the correspondence between the optical port number, the used wavelength λ2, and the PSW port number (step 404), and the optical path to the head node, the rear end node, and the relay node. A setting notification is transmitted (step 405).

  As shown in FIG. 8, when receiving the optical path setting notification, the node N4 of the leading node causes the packet flow control management unit 108 to change the output port of the packet switch 107 for the packet flows # 1 and # 2 from the PSW port # 2 to the PSW. The optical switch 104. Is changed to the port # 3, and the OADM / OXC control unit 109 sets the output wavelength of the EO / OE unit 105.3 to λ2 and changes the output optical port from OUT # 2 to OUT # 3. 1 and 102.1 are controlled. Further, the output optical port numbers of packet flows # 1 and # 2 in the packet forwarding table (FDB) 203 (N4) are changed.

  As shown in FIG. 8, when the relay nodes N3 and N2 receive the optical path setting notification, the OADM / OXC control unit 109 controls the optical switch 102.2 to change from the optical port IN # 3 to the optical port OUT # 4. Set cut-through.

  As shown in FIG. 8, when the node N1 of the rear end node receives the optical path setting notification, the OADM / OXC control unit 109 sets the input optical port to IN # 3 and sets the input wavelength of the EO / OE unit 105.3 to λ2. The packet flow control management unit 108 sets the input port of the packet switch 107 for the packet flows # 1 and # 2 to the PSW port # 3.

  Next, wavelength path setting control and flow switching control according to the present embodiment will be described in more detail according to the steps of the flowchart shown in FIG. First, the optical path setting control unit 14a confirms whether there is congestion in the PSW output port notified from the node (step 501), recognizes the node that first detected congestion as a head (head) node, At least one flow Q is specified (step 502).

  Subsequently, the optical path setting control unit 14a notifies the free resource information notified from the head node, that is, the optical port for setting a new wavelength path, the OE / EO unit, the optical switch port, the port (PSW port) of the packet switch, and the like. Is checked (step 503). If it does not exist ("None" in step 504), the new wavelength path setting is not performed and the operation is terminated. If there is a resource (“Yes” in step 504), the free wavelength information that can be used on the optical fiber transmission line between the downstream node and the packet flow Q that is a congestion factor is acquired (step 505). Further, the congestion state of the packet flow Q in the downstream node is confirmed (step 506). When the congestion state of the packet flow Q is confirmed in the downstream node (“Yes” in Step 507), Steps 503 to 506 are repeated for the downstream node, and the congestion confirmation of the downstream nodes is sequentially executed.

  If it is determined that there is no congestion in a certain downstream node (“None” in step 507), the node is recognized as a tail (rear end) node of the packet flow Q, and the optical port, OE / EO unit, optical It is confirmed whether or not resources such as a switch port and a packet switch port (PSW port) exist (step 508). If the resource does not exist (“None” in step 509), the operation ends. If it exists (“Yes” in step 509), the new wavelength path is calculated from all usable wavelength information from the Head node to the Tail node. The wavelength to be set as is determined (step 510). In this way, a node section where congestion is detected is specified, and a wavelength used in a wavelength path to be set between them is determined.

  When the wavelength of the new wavelength path is determined, the optical path setting control unit 14a sets the connection between the optical port for setting the new wavelength path and the corresponding PSW port in the tail node, and sets the OE / EO unit at the new transmission wavelength. (Step 511). Finally, the optical path setting control unit 14a determines whether or not there is a relay node in the packet flow Q (step 512). If there is a relay node ("Yes" in step 512), the optical path setting control unit 14a uses the new wavelength for the relay node. Cut-through setting is performed (step 513), and then a connection between the optical port for setting a new wavelength path and the corresponding PSW port is set for the head node (step 514). Thus, a new wavelength path is set between the head node and the tail node.

  After the new wavelength path is established, the output optical port numbers of the packet flows # 1 and # 2 in the packet transfer table FDB of the Head node are newly set in the Head node by rewriting the port # 2 to the port # 3. The packet flow is transferred to the output optical port # 3 and the corresponding output PSW port # 3 (step 515).

  Although not shown, when wavelength path setting and packet flow are switched on the opposite side, the same operation may be applied to wavelength path setting and packet flow control on the opposite side.

  Further, in the packet forwarding table FDB, when the packet flow is transferred to the wavelength path by rewriting the output optical port number for each packet flow, it is not always necessary to target all the flows involved in the congestion detection port. It is also possible to transfer only a part of the packet flows to the wavelength path so that the total bandwidth is below an appropriate threshold.

  Furthermore, after a wavelength path from the node N4 to the node N1 as shown in FIG. 8 is set, when a new packet flow occurs through the node N4 and the node N1, the capacity of the existing wavelength path is not exceeded. The new packet flow can be merged with the wavelength path.

3.3) Effect As described above, according to the first embodiment of the present invention, based on the presence / absence of congestion from each node and free resource information, the optical path setting control unit 14a sets the wavelength path for eliminating the congestion. By setting and switching at least one flow to the newly set wavelength path at the leading node and the trailing node, it is possible to improve the wavelength utilization efficiency and reduce the packet processing load.

  In other words, according to the present embodiment, the traffic volume in the packet flow unit is monitored for Ingress / Egress within the node, and offloading to single or multiple wavelength paths in the packet flow unit by rewriting the output port of the packet forwarding table. The following effects can be acquired by having the means to do. (1) Communication of packet flow exceeding the wavelength path bandwidth and wavelength path setting between adjacent nodes can be performed. (2) For a plurality of packet flows received from adjacent upstream nodes, when a flow transiting the own node and a flow dropping at the own node are mixed, if the traffic amount of the received packet flow increases, a wavelength path is set and transited The flow can be offloaded to the wavelength path. (3) Port utilization efficiency of the packet switch can be improved.

  Further, the traffic amount in the packet flow unit is monitored for Ingress / Egress within the node, and when a new packet flow exceeding the traffic amount threshold value occurs, if it can be accommodated in the already set wavelength path, the packet flow unit Therefore, the wavelength utilization efficiency can be improved and the packet processing load can be reduced.

4). Second Embodiment In the first embodiment shown in FIG. 5, the optical path setting control unit 14 is provided separately from each node. However, the present invention is not limited to this configuration, and each node device is provided. The optical path setting control unit 14 may be incorporated. That is, the same function as that of the first embodiment can be realized by the optical path setting control unit 14 of each node communicating a control signal with each other. The node device and its network path setting and flow switching control according to the second embodiment of the present invention will be described below. Hereinafter, the reference number of the optical path setting control unit 14 in the present embodiment is assumed to be “14b”. In this embodiment, a linear topology network is exemplified as described above, but the present invention is not limited to this network configuration.

4.1) Configuration As shown in FIG. 10A, the optical path setting control unit 14b of each node can use the WDM signal as means for communicating with each other and can be interconnected via an optical fiber transmission line. . As another example, as shown in FIG. 10B, the optical path control units 14b may be directly connected to each other via a LAN (Local Area Network) or the like. As described above, by distributing and arranging the optical path setting control unit 14b, it is not necessary to simplify communication lines and network equipment for installation and installation and installation work, and to install servers and computers for centralized processing. Therefore, there is an effect that the equipment cost can be reduced.

4.2) Operation As shown in FIG. 11, the wavelength path setting and the flow switching operation in the node device and the network according to this embodiment are basically the same as those in the first embodiment. The difference from the first embodiment described above is whether the own node is a head node, a relay node, or a tail node based on a notification signal received from another node by the optical path setting control unit 14b that is distributed. The point is that the determination is made and the processing is executed according to the procedure shown in FIG. Accordingly, wavelength path setting and flow switching operation in each node will be described with reference to FIG.

  In FIG. 12, first, the optical path setting control unit 14b of each node confirms the presence or absence of congestion at the PSW output port of its own node and notifies the congestion information to the downstream node (step 601). It waits for a notification from the upstream node for a certain time (step 602), and determines whether it is a head node, a relay node, or a tail node according to the presence / absence of congestion of the own node and the presence / absence of notification from the upstream ( Step 603). Specifically, if it is “no notification / congestion”, it is determined to be a head node, “notification / congestion” is determined as a relay node, and “notification / congestion is not included” is determined as a tail node. A generation node section, that is, a new setting section of a wavelength path is determined.

  If the own node is a Head node, the optical path setting control unit 14b of the own node has available resource information, that is, an optical port for setting a new wavelength path, an OE / EO unit, an optical switch port, and a packet switch port (PSW). Port) or the like exists (step 610). If it does not exist (“no space” in step 610), the new wavelength path setting is not performed and the operation is terminated. If there is a resource (“available” in step 610), the available available wavelength information is acquired (step 611), and the congestion state of the downstream node related to the flow Q that is the congestion factor is confirmed. Notification of free wavelength information of the own node is performed (step 612), and reception of a wavelength path setting notification is awaited (step 613). When the wavelength path setting notification is received (step 614), the optical path setting control unit 14b of the own node sets the connection between the optical port for setting the new wavelength path and the corresponding PSW port (step 615), A new wavelength path is set up with the tail node. When the new wavelength path is set, the optical path setting control unit 14b rewrites the output optical port numbers of the packet flows # 1 and # 2 in the packet forwarding table FDB from the port # 2 to the port # 3 (step 616), and the Head node The packet flow is transferred to the newly set output optical port # 3 and the corresponding output PSW port # 3 (step 617).

  If the own node is a relay node, the optical path setting control unit 14b of the own node has available resource information, that is, an optical port for setting a new wavelength path, an OE / EO unit, an optical switch port, and a packet switch port (PSW). Port) or the like exists (step 620). If it does not exist (“no space” in step 620), the new wavelength path setting is not performed and the operation is terminated. If there is a resource (“available” in step 620), the available available wavelength information is acquired (step 621), and the congestion state of the downstream node related to the flow Q that is the congestion factor is confirmed. Notification of free wavelength information of the own node is performed (step 622), and reception of a wavelength path setting notification is awaited (step 623). When the wavelength path setting notification is received (step 624), the optical path setting control unit 14b of the own node performs cut-through setting of the own node (step 625).

  If the own node is a Tail node, the optical path setting control unit 14b of the own node has available resource information, that is, an optical port for setting a new wavelength path, an OE / EO unit, an optical switch port, and a packet switch port (PSW). Port) or the like exists (step 630). If it does not exist (“no space” in step 630), the new wavelength path setting is not performed and the operation is terminated. If there is a resource (“available” in step 630), the optical path setting control unit 14b determines a free wavelength to be used (step 631), and a PSW port corresponding to the optical port for setting a new wavelength path (Step 632). Subsequently, the optical path setting control unit 14b transmits a wavelength path setting notification to the head node and the tail node.

  Although not shown, when wavelength path setting and packet flow are switched on the opposite side, the same operation may be applied to wavelength path setting and packet flow control on the opposite side.

  Further, in the packet forwarding table FDB, when the packet flow is transferred to the wavelength path by rewriting the output optical port number for each packet flow, it is not always necessary to target all the flows involved in the congestion detection port. It is also possible to transfer only some packet flows to the wavelength path so that the total bandwidth is below an appropriate threshold.

4.3) Effect As described above, according to the second embodiment of the present invention, the wavelength utilization efficiency is improved and the packet processing load is changed by switching at least one flow to the newly set wavelength path as in the first embodiment. Can be achieved, and the optical path setting control unit 14b is distributed to each node, thereby simplifying communication lines, network equipment, and laying work for interconnection, and a server for centralized processing. Installation of computers and the like is not necessary, and equipment costs can be reduced.

5. Third Embodiment In the first and second embodiments described above, the case where there is one newly set wavelength path is illustrated, but the present invention is not limited to this. It is also possible to newly set a plurality of wavelength paths, set them as virtual links such as LAG (Link Aggregation) defined in IEEE802.3ad, and set them as a link having a bandwidth of more than a single wavelength path virtually. is there.

  In this case, an information table corresponding to the virtual link setting (that is, the PSW / optical port correspondence table 201, the packet forwarding table (FDB) 202 and the PSW port bandwidth monitor table 203 shown in FIG. 3) and the packet switch 107 are required. 6 to 9 or FIGS. 11 to 12 showing the operation flow also require a procedure for setting a virtual link. Other configurations and operations are the same as those in the first or second embodiment.

  Thus, by virtualizing a plurality of wavelength paths, a packet flow exceeding the band of a single wavelength path can be offloaded to the wavelength path.

6). Second Embodiment Although the node device 10 according to the first embodiment of the present invention shown in FIG. 2 has a PSW port for connecting a client IF to the packet switch 107, the client switch and the client IF are connected from the packet switch 107. PSW ports can also be eliminated.

  As shown in FIG. 13, in the node device 10a according to the second embodiment of the present invention, the client IF and the PSW port connecting the client IF are excluded from the packet switch 107, and the other configurations and functions are the same as in the first embodiment. It is.

  As shown in FIG. 14, in a network composed of Core nodes 701 and 702 and Edge nodes 703 to 705, function sharing is performed between Edge nodes 703 to 705 that aggregate clients and Core nodes 701 and 702 that aggregate Edge nodes. The node device 10a shown in FIG. 13 is applied to the Core node, and the node device 10 shown in FIG. 2 is applied to the Edge node. This makes it possible to optimize device resources such as the configuration of the OADM / OXC unit 11, the PSW port bandwidth of the packet switch 107, and the scale of the switch fabric.

  According to the present embodiment, a device resource configuration optimized for the Core node and the Edge node can be achieved, and a reduction in device cost and a reduction in device size can be achieved.

7). Additional Notes Part or all of the above-described embodiments may be described as the following additional notes, but are not limited thereto.

(Appendix 1)
A plurality of node devices are connected by an optical transmission line, and each node device is a wavelength path setting device in an optical wavelength division multiplexing network having a configuration in which an optical switch unit and a packet switch unit are integrated,
Each node device has a congestion determination means for determining the presence or absence of congestion by monitoring the traffic amount of a communication packet in a flow unit,
Control means for setting at least one wavelength path for eliminating the congestion based on congestion occurrence information from a node device and switching at least one packet flow involved in the congestion to the wavelength path;
A wavelength path setting device comprising:

(Appendix 2)
The control means detects a congestion node section where congestion occurs based on the congestion occurrence information, controls a node device in the congestion node section, sets the at least one wavelength path, and sets the at least one wavelength The wavelength path setting device according to appendix 1, wherein one packet flow is switched to the wavelength path.

(Appendix 3)
The node device has a packet transfer table for transferring a packet, and the control means outputs an output port in the packet transfer table for the at least one packet flow specified by the wavelength path. The wavelength path setting device according to appendix 2, wherein the wavelength path setting device is rewritten as follows.

(Appendix 4)
The wavelength path setting device according to any one of appendix 1-3, wherein a plurality of wavelength paths are set to a band exceeding a band of a single wavelength path by virtual link.

(Appendix 5)
The wavelength path setting device according to any one of appendix 1-4, wherein the wavelength device is connected to each node device so as to be able to communicate separately from the plurality of node devices.

(Appendix 6)
The wavelength path setting device according to any one of appendix 1-4, wherein the wavelength path setting device is provided in each of the plurality of node devices and is communicably connected to wavelength path setting devices of other node devices.

(Appendix 7)
A wavelength path setting method in an optical wavelength division multiplexing network in which a plurality of node devices are connected by an optical transmission line, and each node device has a configuration in which an optical switch unit and a packet switch unit are integrated,
Each node device determines the presence or absence of congestion by monitoring the amount of traffic in the communication packet flow unit,
The control means sets at least one wavelength path for eliminating the congestion based on congestion occurrence information from the node device, and switches at least one packet flow involved in the congestion to the wavelength path.
And a wavelength path setting method.

(Appendix 8)
The control means detects a congestion node section where congestion occurs based on the congestion occurrence information, controls a node device in the congestion node section, sets the at least one wavelength path, and sets the at least one wavelength The wavelength path setting method according to appendix 7, wherein one packet flow is switched to the wavelength path.

(Appendix 9)
The node device has a packet transfer table for transferring a packet, and the control means outputs an output port in the packet transfer table for the at least one packet flow specified by the wavelength path. The wavelength path setting method according to appendix 8, wherein the wavelength path setting method is rewritten as follows.

(Appendix 10)
The wavelength path setting method according to any one of appendix 7-9, wherein a plurality of wavelength paths are set to a band exceeding a band of a single wavelength path by virtual linking.

(Appendix 11)
A node device in an optical wavelength division multiplexing network having a configuration in which an optical switch unit and a packet switch unit are integrated,
Congestion determination means for determining the presence or absence of congestion by monitoring the amount of traffic in a communication packet flow unit;
Communication means for communicating with a wavelength path setting device for setting at least one wavelength path for eliminating the congestion based on congestion occurrence information from a node device;
Control means for setting at least one wavelength path in accordance with a wavelength path setting notification from the wavelength path setting device and switching at least one packet flow involved in the congestion to the wavelength path;
A node device comprising:

(Appendix 12)
A node device in an optical wavelength division multiplexing network having a configuration in which an optical switch unit and a packet switch unit are integrated,
Congestion determination means for determining the presence or absence of congestion by monitoring the amount of traffic in a communication packet flow unit;
Wavelength path setting means for setting at least one wavelength path for eliminating the congestion based on congestion occurrence information by communication with other node devices;
Control means for setting at least one wavelength path in accordance with a wavelength path setting notification from the wavelength path setting means, and for switching at least one packet flow involved in the congestion to the wavelength path;
A node device comprising:

(Appendix 13)
An optical wavelength division multiplexing network in which a plurality of node devices are connected by an optical transmission line,
Each node device has a configuration in which the optical switch unit and the packet switch unit are integrated, and determines the presence or absence of congestion by monitoring the traffic amount of each communication packet in a flow unit,
A wavelength path setting device transmits a notification for setting at least one wavelength path for eliminating the congestion to the node device based on congestion occurrence information from the node device,
The node device switches at least one packet flow involved in the congestion to the wavelength path according to the wavelength path setting notification;
An optical wavelength division multiplexing network.

(Appendix 14)
The wavelength path setting device detects a congestion node section in which congestion occurs based on the congestion occurrence information, and controls the node device in the congestion node section, so that the node device has the at least one 14. The optical wavelength division multiplexing network according to appendix 13, wherein a wavelength path is set and the at least one packet flow is switched to the wavelength path.

(Appendix 15)
The node device has a packet forwarding table for forwarding a packet, and rewrites an output port in the packet forwarding table to an output port specified by the wavelength path for the at least one packet flow. The optical wavelength division multiplexing network according to appendix 14.

(Appendix 16)
The optical wavelength division multiplexing network according to any one of appendix 13-15, wherein a plurality of wavelength paths are set to a band exceeding a band of a single wavelength path by virtual linking.

(Appendix 17)
The optical wavelength division multiplexing network according to any one of appendix 13-16, wherein the wavelength path setting device is connected to each node device separately from the plurality of node devices.

(Appendix 18)
The wavelength path setting device is provided in each of the plurality of node devices, and is connected so as to be able to communicate with wavelength path setting devices of other node devices. Optical wavelength division multiplexing network.

  The present invention is applicable to a node in which the ROADM / WXC function and the packet transfer function are integrated in an optical WDM network.

DESCRIPTION OF SYMBOLS 10, 10a Node apparatus 11 OADM / OXC part 12 Packet frame transfer part 13 Node control part 14, 14a, 14b Optical path setting control part 101 Wavelength separation filter 102 Optical switch 103 Wavelength multiplexing filter 104 Optical switch 105 EO / OE part 106 Data link / physical layer processing unit 107 packet switch 108 packet flow control management unit 109 OADM / OXC control unit 201 PSW / optical port correspondence table 202 packet transfer table (FDB)
203 PSW port bandwidth monitor table 301 Wavelength path 302, 303 Packet flow

Claims (9)

A plurality of node devices are connected by an optical transmission line, and each node device is a wavelength path setting device in an optical wavelength division multiplexing network having a configuration in which an optical switch unit and a packet switch unit are integrated,
Each node device has a congestion determination means for determining the presence or absence of congestion by monitoring the traffic amount of a communication packet in a flow unit,
Control means for setting at least one wavelength path for eliminating the congestion based on congestion occurrence information from a node device and switching at least one packet flow involved in the congestion to the wavelength path;
I have a,
The control means specifies a node that first detects congestion as a leading node, identifies at least one packet flow involved in the congestion, and indicates the congestion state of the identified packet flow to a downstream node. Sequentially confirming that a downstream node that has been confirmed as having no congestion is a trailing node of the packet flow, detects a congestion node section where congestion occurs based on the congestion occurrence information, and the congestion node section Controlling a certain node device to set the at least one wavelength path and switch the at least one packet flow to the wavelength path;
A wavelength path setting device. The node device has a packet transfer table for transferring a packet, and the control means outputs an output port in the packet transfer table for the at least one packet flow specified by the wavelength path. The wavelength path setting device according to claim 1 , wherein: The wavelength path setting device according to claim 1 or 2 , wherein a plurality of wavelength paths are set to a band exceeding a band of a single wavelength path by virtual linking. The separately from the plurality of node devices, the wavelength path setting apparatus according to any one of claims 1 3, characterized in that communicatively connected to each node device. The wavelength path setting device according to any one of claims 1 to 3 , wherein the wavelength path setting device is provided in each of the plurality of node devices and is communicably connected to wavelength path setting devices of other node devices. A wavelength path setting method in an optical wavelength division multiplexing network in which a plurality of node devices are connected by an optical transmission line, and each node device has a configuration in which an optical switch unit and a packet switch unit are integrated,
Each node device determines the presence or absence of congestion by monitoring the amount of traffic in the communication packet flow unit,
Based on the congestion occurrence information from the node device, the control means specifies the node that first detected the congestion as a leading node, identifies at least one packet flow involved in the congestion, and The congestion state of the identified packet flow is sequentially confirmed, and the downstream node that has been confirmed as having no congestion is set as the rear end node of the packet flow, thereby detecting the congestion node section where the congestion occurs, Controlling a node device in a congestion node section to set the at least one wavelength path and switch the at least one packet flow to the wavelength path;
And a wavelength path setting method. 6. At least one wavelength path is set according to the wavelength path setting notification from the wavelength path setting device according to claim 1, and at least one packet flow involved in the congestion is transferred to the wavelength path. Control means for switching;
A node device comprising: A node device in an optical wavelength division multiplexing network having a configuration in which an optical switch unit and a packet switch unit are integrated,
Congestion determination means for determining the presence or absence of congestion by monitoring the amount of traffic in a communication packet flow unit;
Wavelength path setting means for setting at least one wavelength path for eliminating the congestion based on congestion occurrence information by communication with other node devices;
Control means for setting at least one wavelength path in accordance with a wavelength path setting notification from the wavelength path setting means, and for switching at least one packet flow involved in the congestion to the wavelength path;
I have a,
The wavelength path setting means specifies the at least one packet flow involved in the congestion if the node device detects the congestion first, identifies at least one packet flow involved in the congestion, and specifies the identification for the downstream node. If the node device is confirmed to be free of congestion, the identified packet flow is switched to the wavelength path for the node up to the first node as a rear-end node. The wavelength path setting notification to be controlled as described above is transmitted . An optical wavelength division multiplexing network in which a plurality of node devices are connected by an optical transmission line,
Each node device has a configuration in which the optical switch unit and the packet switch unit are integrated, and determines the presence or absence of congestion by monitoring the traffic amount of each communication packet in a flow unit,
A wavelength path setting device transmits a notification for setting at least one wavelength path for eliminating the congestion to the node device based on congestion occurrence information from the node device,
The node device switches at least one packet flow involved in the congestion according to the wavelength path setting notification to the wavelength path ,
The wavelength path setting device specifies a node that first detects congestion as a leading node, identifies at least one packet flow involved in the congestion, and congestion of the identified packet flow with respect to a downstream node The state is sequentially checked, and the downstream node that has been confirmed as having no congestion is set as the rear-end node of the packet flow, so that a congestion node section where congestion has occurred is detected based on the congestion occurrence information, and the congestion node Sending the wavelength path setting notification for controlling the specified packet flow to switch to the wavelength path to the nodes in the section;
An optical wavelength division multiplexing network.

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