JP4016023B2 - Packet transmission system - Google Patents

Description

  The present invention relates to a packet transmission system formed by overlaying an all-optical network or the like to which cut-through technology is applied on a transmission network that performs packet-based switching.

  Advances in Internet technology are fast. The traffic flowing through the communication network was mainly fixed telephone traffic in the early 1990s, but now most of it is data traffic flowing through the Internet. With the explosive spread of the Internet and broadband, the metro and trunk line traffic that supports the Internet is also increasing rapidly. From this background, the traffic that can be accommodated in the existing communication network is approaching its limit.

  Therefore, a technique for overlaying a photonic network having an optical cross-connect as a node on an existing network and transferring traffic that cannot be accommodated in the existing network to the photonic network has been studied (for example, Patent Document 1 and Non-Patent Documents). Reference 1). The traffic of the existing network is accommodated in the optical path set in the photonic network, whereby the intermediate node is cut through. Setting the optical path temporarily as needed can reduce the initial investment in the photonic network than setting the optical path fixedly.

In particular, Non-Patent Document 1 attempts to reduce the cost of the system by limiting the number of optical transceivers provided in each node. In exchange for this, a mesh topology cannot always be formed with an optical path, so that a process for setting and releasing an optical path is frequently required. For this procedure, GMPLS (Generalized Multi Protocol Label Switching) or the like is used. In this type of protocol, signaling related to path setting is performed mainly by a node called an ingress node or an egress node according to the positioning. As the optical path is set and released, packet traffic travels between the default wavelength LSP (label switch path) and the optical path.
JP 2002-016950 A IEICE 2003 Society Conference B-6-140

  By the way, in the architecture as described above, even in the combination of the same ingress node and egress node, the amount of delay for packet transmission between the LSP and the optical path differs. The optical path cuts through a node on the way, whereas in LSP, a packet (that is, a labeled packet) is switched store-and-forward by an LSR (label switch router) for each node. Therefore, in most cases, the packet delay amount in the LSP is larger. However, since the delay amount changes from moment to moment due to various factors, it is impossible to know in advance how large the delay amount of the LSP is compared to the optical path. Further, depending on the route, the LSP is not always slower, and the delay of the optical path may be large.

  When an optical path is set and released in such a network, the packet placed in the path to which traffic is transferred (migration destination path) is put in the path before the traffic is transferred (migration source path). May overtake packets. This can occur in both cases where traffic is transferred from the LSP to the optical path, and conversely, when traffic is transferred again from the optical path to the LSP.

  For example, it is assumed that, during the optical path setting process, one of the two consecutive packets that has flowed to the LSP and the other that has flowed to the optical path. At this time, due to the difference in delay between the two paths, the subsequent packet may reach the egress node first. As described above, the order between packets may be reversed when an optical path is set, and the same phenomenon may occur during an optical path release process.

  In order to avoid changing the order of the packets, it is considered that the labeled packets are buffered and the path is switched after the transmission to the LSP is completed. In addition, more effective measures are being sought.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a packet transmission system that prevents packet loss from occurring by preventing reversal of packet order, thereby improving communication quality.

In order to achieve the above object, according to one aspect of the present invention, a labeled packet is transmitted through a plurality of nodes and a plurality of label switch paths set between an arbitrary node from an output port of each of the plurality of nodes. In a packet transmission system comprising a first network for transferring a second network and a second network capable of setting a cut-through type optical path between the plurality of nodes, priority is given to the labeled packets by giving priority to them individually Prioritizing means for inserting into the label switch path with a shorter transmission delay as the labeled packet having a higher degree, traffic measuring means for measuring the packet traffic transferred through the plurality of label switch paths for each output port , If the packet traffic measured by this traffic measurement means exceeds the specified threshold, The path setting means for setting an optical path in the second network, and the traffic of the label switch path for transferring the labeled packet having a high priority are preferentially transferred to the optical path set by the path setting means. A packet transmission system comprising a traffic transfer means is provided.

By taking such a measure, a labeled packet set with a high priority is transferred via an LSP with a low transmission delay (referred to as a high priority LSP) in the first network. The time is short. The high priority LSP is preferentially switched to the optical path on the second network when the traffic congestion approaches. By such processing, it is possible to reduce fluctuations in delay time of labeled packets having high priority during path switching processing. This makes it possible to minimize the order reversal of labeled packets at the LSP end point node. For example, the delay time of the labeled packet does not increase even when the labeled packet is buffered to prevent the order from being reversed. Therefore, communication quality can be improved.

  Also, there is no need to guarantee the delay time of labeled packets with low priority. When the path switching of the low priority packet is necessary, the high priority packet has already been detoured to the second network side, and the number of competitors is reduced. Therefore, order reversal in the low priority packet can also be prevented. As a result, the communication quality can be further improved.

  According to the present invention, it is possible to prevent packet order reversal, thereby providing a packet transmission system in which occurrence of packet loss is suppressed and communication quality is improved.

  FIG. 1 is a system diagram showing an embodiment of a packet transmission system according to the present invention. The system of FIG. 1 includes a plurality of nodes 103 (103-1 to 103-5). Each of the nodes 103-1 to 103-5 includes a label switch router (LSR) 101 (101-1 to 101-5) and a photonic cross connect (PXC) 102 (102-1 to 102-5). .

  The nodes 103-1 to 103-5 are appropriately connected via the optical transmission lines 104-1 to 104-6. Each of the optical transmission lines 104-1 to 104-6 is composed of a plurality of wavelength-multiplexed optical links, and one of the wavelengths λ0 is a default wavelength, and the nodes are connected hop-by-hop. That is, the wavelength λ0 is always subjected to photoelectric conversion for each node, and electrical processing of the signal is performed. The wavelength λ0 is used for transmission of network control signals and L2 / L3 layer packets. The packet passing through the L2 / L3 layer is switched by the label switch router 101 of the node that has passed through until reaching the destination.

  In the plane indicated as the L2 / L3 layer in FIG. 1, dotted arrows connecting the LSRs indicate that the nodes are logically mesh-connected. The logical route that connects each node to the mesh is called a label switch path (LSP). The mesh connection is only logical, and in practice, packets passing through this network proceed through the LSP while being switched hop-by-hop by LSR.

  The LSR has a function of measuring traffic of an LSP passing through its own node. When each node 103-1 to 103-5 detects that the traffic of a certain LSP has increased, it cuts through the traffic of that LSP at the L1 layer. Specifically, an L1 layer optical path passing through the PXC is set along the route through which the LSP passes, and the LSP traffic is transferred to the optical path.

  The PXC has a function of connecting light of an arbitrary wavelength input to an arbitrary input port to an arbitrary output port without converting the light into an electric signal and without performing wavelength conversion. Therefore, the optical path starts from the start point node, passes through several PXCs without being wavelength-converted, and reaches the end point node.

  In FIG. 1, for example, when an LSP that connects LSRs 101-1 and 101-3 is cut through in the L1 layer, it is assumed that the LPS physically passes through LSRs 101-1, 101-2, and 101-3. . If an optical path setting request is made to the nodes 103-1, 103-2, and 103-3 and the request is accepted by satisfying the conditions such as the wavelength, the optical paths that pass through the PXCs 102-1, 102-2, and 102-3 105 is set. Note that a node (ingress) issuing an optical path setting request is one of the nodes 103-1, 103-2, and 103-3.

  When the optical path 105 is successfully set, the node 103-1 directs the LSP traffic that is stretched toward the LSR 101-3 input to the LSR 101-1 toward the PXC 102-1, and the node 103-3 is transmitted by the optical path 105. To reach. The node 103-3 directs the traffic of the optical path 105 reaching the PXC 102-3 to the LSR 101-3. In this way, the node 103-2 is cut through and the load on the LSR 101-2 is reduced.

  In the system of FIG. 1, MPLS (Multi-Protocol Label Switching) standardized by IETF (Internet Engineering Task Force) is used to set an optical path in a photonic network. In recent years, GMPLS (Generalized MPLS), which is an extension of this, is often used. In addition, there are known label distribution protocol (LDP) and RSVP-TE (Resource Reservation Protocol-Traffic Engineering) used for resource reservation. By interpreting “label” as “wavelength”, these protocols can be used for optical path setting processing.

  In the optical path setting process using the above protocol, when the traffic flowing on the label switch path (LSP) exceeds a predetermined threshold, the optical path setting request message is sent to the start point of the LSP (ingress). Arrives at the node. The start node of the LSP that has received the optical path setup request message transmits the optical path request message to the end point (egress) node of the LSP. The optical path is set by returning the optical path reserve message from the LSP end point node that has received the optical path request message to the start point of the LSP.

  The start point node of the LSP changes the label value of the packet when the optical path setting is completed or after a specific waiting time, and flows the labeled packet to the optical path. The optical path passes through the intermediate node in the state of an optical signal. On the other hand, a labeled packet transferred on the LSP is once converted into an electric signal at a midway node, and then converted into an optical signal again through a label switch.

  In the existing system having the network architecture of FIG. 1, after a certain time has elapsed after the optical path is established, the optical path is forcibly released regardless of the traffic in the optical path. Therefore, after the optical path is released, if there is still a lot of traffic in the corresponding LSP, an optical path setting request is generated again.

  Packets traveling on the LSP are switched each time they pass through the LSR. The LSR queues the input packet in the buffer of the corresponding output port by store and forward. If the buffer is empty, the packet will immediately go out of the LSR, but if there are other packets in the buffer, they will not be output until the turn comes. On the other hand, since the PXC only connects the input and the output as a line, a packet traveling on the optical path almost passes through the PXC. Accordingly, the delay performance is clearly different between the case where packets of the same destination pass through the LSP and the case where they pass through the optical path.

  LSP packets with high traffic are stored in the buffer of the transit node. When a packet flowing on the LSP is switched to the optical path in this state, there is a possibility that the packet flowing on the optical path overtakes the packet flowing on the LSP, and the order of the packets is switched at the LSP end point node.

  That is, when there is little traffic, there is no contention for the output port, so the delay is not large. On the other hand, when traffic increases, output port contention occurs, and the delay of labeled packets increases rapidly. When the labeled packet is switched from the LSP to the optical path at the start point node of the LSP when the traffic amount becomes large, the delay of the labeled packet transferred by the LSP is increased at the end point node of the LSP. There is a possibility that the labeled packet transferred on the optical path arrives first. In the following, an embodiment of the present invention capable of solving such problems is disclosed.

  FIG. 2 is a diagram illustrating the accommodation relationship between the LSP and the optical path in the nodes 103-1, 103-2, and 103-3 in FIG. This figure is changed from the LSP start point nodes LSR 101-1 and OXC 102-1 in FIG. 1 to the LSP end point nodes LSR 101-3 and OXC 102-2 through the LSR 101-2 and OXC 102-2 nodes. LSP and optical path to reach. 2 receives an IP packet from an external IP (Internet Protocol) network, for example, and outputs an IP packet from the LSR 101-3 toward the external IP network.

  In the external IP network, for example, in the case of IPv4, a 3-bit area indicating the priority of the packet is secured in the TOS area of the IP header. Recent IP routers have a mechanism for transferring high priority packets with low delay by inputting priorities into the TOS area of IP packets output from an end system. This function is called DiffServ.

  The IP router changes the priority of queuing the packet to the output port according to the priority indicated in the TOS area. Also in the photonic network shown in FIG. 1, as in DiffServ, the priority of a packet is recognized and a high priority packet is transferred with a low delay.

  The LSR 101-1 in FIG. 2 functions as an edge LSR. That is, the LSR 101-1 has a function of adding a label to an IP packet input from an external network according to its priority. The label is provided with a 32-bit area, in which three experimental bits capable of describing the priority are defined. The edge LSR copies the priority area of the 3-bit TOS area of the input IP packet to the experimental bit of the label.

  The method for mapping the priority of the label is not limited to this, and it may be changed according to the protocol type of the IP header, or may be mapped to the priority of the label according to the port number of the TCP or UDP header. . It is also conceivable to set a plurality of LSPs according to the priority of the input IP packet. High priority IP packets are transferred on the high priority LSP, and low priority IP packets are transferred on the low priority LSP.

  FIG. 2 shows two LSPs between the ingress edge LSR 101-1 and the egress edge LSR 101-3 to avoid complications. These two LSPs are a low priority LSP 201 and a high priority LSP 202. Actually, three bits, that is, eight levels of priority can be set, so eight LSPs may be set. The high priority IP packet input to the edge LSR 101-1 is transferred on the high priority LSP 202, and the low priority IP packet is transferred on the low priority LSP 201.

  Labeled packets on the high priority LSP are preferentially transferred in the LSRs 101-1, 101-2, and 101-3. The LSR is a switch in which an output label value and an output port are determined by referring to a transfer label table according to a label value of a labeled packet input to the LSR. When labeled packets transferred to the same output port concentrate, an output port race condition occurs.

  Generally, the operating speed inside the switch is set to be higher than the data rate output from the output port. Therefore, even if the output port competes, the packet is not immediately discarded inside the switch. However, a labeled packet cannot be transmitted at a rate exceeding the data rate output from the output port. Therefore, by providing a buffer memory for the switch output, packets are not discarded immediately even if output port contention occurs. The buffer of the output port is not necessarily provided on the output side of the switch, but can be provided on the input side of the switch to be a virtual output buffer.

  As traffic increases, labeled packets accumulate in the output buffer memory. In a situation where labeled packets are accumulated, the high priority labeled packets are output immediately, and the low priority labeled packets are accumulated in the buffer memory. As a result, the high priority labeled packet can transfer the LSP with low delay.

  Here, a high-priority labeled packet is assigned a priority with respect to a specific input label by assigning a priority in a label path unit and a method for identifying and identifying the priority in the experimental bit 3 bits of the label of the labeled packet. A method to raise it is considered.

  The LSRs 101-1, 101-2, and 101-3 have a function of monitoring traffic in units of output ports based on the accumulated amount of labeled packets in the buffer memory existing in units of output ports of the switch. When traffic above the output data rate enters the buffer memory, the labeled packet is accumulated. This accumulated amount is compared with a predetermined threshold value, and when the accumulated amount of labeled packets exceeds the threshold value, the LSRs 101-1, 101-2, and 101-3 are all accumulated. A labeled packet having the highest priority among the labeled packets is selected. When there are a plurality of labeled packets having the highest priority, one LSP to which the labeled packet is transferred is selected from the group using another attribute. Other attributes include the number of hops of a node, distance, bandwidth thickness, and the like.

  The LSP to which the selected labeled packet is transferred has a high priority path. An optical path setting request message is transmitted toward the start point node 101-1 of this LSP. The LSP start point node 101-1 that has received the optical path setting request message transmits an optical path request message toward the corresponding end point node 101-3 of the LSP. Receiving the optical path request message, the end point node 101-3 of the LSP outputs an optical path reserve message to the start point node of the LSP. The midway node 101-2 sets the OXC 102-2 by the optical path reserve message. In addition, the LSP start node 101-1 that has received the optical path reserve message sets the OXC 102-1 and moves the labeled packet that has been transferred on the high priority LSP so far onto the optical path 203. The GMPLS framework standardized by IETF can be used for signaling for setting up an optical path in this procedure. In addition, an optical path may be set using a similar signaling protocol.

  In the above description, the LSP having the highest priority among the labeled packets stored in the output buffer memory is selected. When there are a plurality of LSPs with the highest priority, a single LSP is selected using another attribute. In addition, even when there are a plurality of high-priority LSPs, the labels are pushed using a stack of labels standardized by MPLS, and a plurality of LSPs with the highest priority are It is possible to group them with labels. Such a tunnel LSP in which a plurality of LSPs are collected may be set at the same time when the LSP is set.

  When the accumulated amount of the output buffer memory of the node increases and exceeds the threshold value, an optical path setting request is issued to the start node of the tunnel LSP, and the optical path is set in the same manner as described above. By moving the entire tunnel LSP onto the set optical path, a plurality of high priority LSPs can be transferred to the optical path.

  A labeled packet having a high priority has a short delay time at a midway node when transferred on the LSP. Therefore, even if a labeled packet with a high priority is switched and transferred on the optical path, the order of the labeled packets is not changed at the LSP end node, or even if the order is changed, a small amount of packets Become. Therefore, the capacity of the buffer memory for preventing the order of the labeled packets from being changed can be reduced. As a result, high priority packets can always be transferred with a small delay time. Further, for low priority packets, high priority data traffic is transferred to the optical path, so that low priority LSPs can be afforded and delays are alleviated.

  FIG. 3 is a functional block diagram showing an embodiment of a node device according to the present invention. The node 103 in FIG. 3 includes a label switch router 101 and a photonic cross connect 102. The photonic cross connect 102 includes an optical matrix switch 11, a wavelength multiplexing MUX / DMUX 12, and an optical matrix switch control unit 20. For simplicity, the optical matrix switch 11 is an optical space matrix switch in FIG. The wavelength multiplexing MUX / DMUX 12 can separate and multiplex three wavelengths λ0, λ1, and λ2, and λ0 is the default wavelength. The optical matrix switch 11 has a function of selecting an arbitrary port within the same wavelength. The number of wavelengths is not limited to three.

  The photonic cross connect 102 is connected to different nodes via the optical transmission path 104. The optical signal of the default wavelength λ0 input / output from the wavelength multiplexing MUX / DMUX 12 is converted into an electrical signal by the default optical transceiver unit 13 of the label switch router 101. The converted electrical signal is switched to the corresponding output port in the label switch function unit 14 based on the label information included in the electrical signal.

  The electrical signal input / output to / from the label switch function unit 14 is packet data composed of a header portion and variable length data. Since a fixed-length label is added to the packet data, it is called a labeled packet. In order for the labeled packet to select and switch an appropriate output port by the label switch function unit 14, it is necessary to refer to a label table indicating the relationship between the label value and the output port. The router unit 16 has a function of creating this label table.

  The router unit 16 has a function of a normal IP (Internet Protocol) router and a label table creation function. When the node 103 operates as an edge device of the network, the router unit 16 is connected to an external network such as an IP network. That is, the router unit 16 has a function of transmitting and receiving IP packets with the IP network. Adjacent nodes are connected by default wavelength λ0.

  When the node 103 operates as an edge device of the network, the router unit 16 can recognize the priority of the IP packet with reference to the TOS area of the header part of the IP packet input from the outside.

  The label switch function unit 14 adds a predetermined default label to the IP packet from the router unit 16 and transfers it to the adjacent node. The label switch function unit 14 to which the default label has been inputted always drops the label and returns it to the original IP packet state before inputting it to the router unit 16. The network formed in this way can behave as an IP router network connected hop-by-hop at the time of startup.

  With this mechanism, the router unit 16 can operate a dynamic routing protocol such as OSPF (Open Shortest Path First). The router unit 16 can automatically create a forwarding table using a dynamic routing protocol. By referring to the destination IP address of the IP packet input to the router unit 16 from the external network, the default label corresponding to the node of the next hop can be selected.

  Similar to the above-described external IP packet transfer mechanism, a label table creation function inside the router unit 16 (not shown) and an IP packet for control input / output from the optical path setup / release control unit 17 It is possible to communicate with the label table creation function and the optical path setting / release control unit of all the nodes.

  In the packet transmission system according to the present invention, an inter-node full mesh label switch path (LSP) is set after the completion of the forwarding table. In order to create a label table, it is necessary to perform LSP signaling for connection. The MPLS technique can be used for LSP signaling. In MPLS, a label table is created by flowing a path request message from a start node of an LSP to a downstream node and determining a label value hop-by-hop using a reserve message from the end node of the LSP to the start node. To do.

  When operating as an edge router, the same priority is mapped to the 3-bit experimental bit area of the label according to the priority of the input IP packet. Alternatively, it is possible to set a plurality of LSPs according to the priority of the input IP packet and to implicitly set the priority to the LSP.

  The traffic measuring unit 19 measures the amount of data traffic in units of output ports measured by the label switch function unit 14. Specifically, a buffer queue may be provided for each output port in the label switch function unit 14, and the traffic measurement unit 19 may monitor the amount of data held in the queue. There is no problem even if the data traffic volume is measured using other methods.

  The LSP priority identification unit 18 identifies the priority order of the labeled packet. Specifically, the priority explicitly indicated by the experimental bit 3 bits of the label portion is identified, or if the priority is implicitly known when the LSP is set, means for storing the priority It shall have.

  When the LSP is stretched to a full mesh, a packet passing through the node 103 is input to the label switch function unit 14 via the default optical transceiver unit 13, but is turned back here and is connected to the adjacent node via the default optical transceiver unit 13. Forwarded to In this situation, when data traffic exceeding a preset threshold is observed by the traffic measuring unit 19, a trigger for an optical path setting request and an identifier of the LSP having the highest priority are set as the optical path setting / release control unit 17. Occurs towards.

  Upon receiving the trigger, the optical path setup / release control unit 17 sends an optical path setup request message toward the start node of the corresponding LSP. The optical path setup request message is converted into a labeled packet by the label switch function unit 14 via the router unit 16, converted into an optical signal of λ0 by the default optical transceiver unit 13, and is transmitted hop-by-hop by the start node of the LSP. Arrives at the optical path setting / release control unit 17.

  Upon receiving the optical path setup request message, the optical path setup / release control unit 17 of the start point node of the LSP sends an optical path request message toward the end point node of the LSP. The procedure relating to this part of signaling is being standardized as GMPLS (Generalized MPLS), which is a more general extension of MPLS. The optical path setup / release control unit 17 of the optical path end point node that has received the optical path request message returns the optical path reserve message to the start point node, and sets the optical matrix switch control unit 20 of the node through which the optical path passes and the start point node. Then, the optical matrix switch 11 is switched.

  The starting point node of the optical path sets the wavelength of the wavelength tunable transceiver unit 15 to the wavelength determined by the GMPLS mechanism, and transfers the data flowing through the LSP via the wavelength tunable transceiver unit 15. This switching can be realized by changing the label table or by changing the label value.

  At an intermediate node in the optical path, the optical signal passes through the optical matrix switch 11 as light, so that the delay time of the data packet is determined only by the optical transit time. As described above, each node 103 monitors traffic in units of output ports, and when detecting a state to be transferred to an optical path (traffic increased beyond a threshold value, etc.), the node 103 has the highest priority among the corresponding output ports. The optical path setup procedure is started for a high-level LSP.

  The optical path setup / release control unit 17 includes a timer (not shown) for measuring the optical path lifetime. The optical path setup / release control unit 17 of the optical path start point node releases an optical path whose lifetime has been exceeded by outputting an optical path release message toward the optical path end point node. At the start node of the optical path, the data transferred through the wavelength tunable transceiver unit 15 is returned to the LSP through the default optical transceiver unit 13.

  As described above, in the present embodiment, the label switch router having the default optical transceiver unit 13 that transmits and receives an optical signal having a common wavelength in all nodes and the plurality of wavelength variable transceiver units 15 that can vary the wavelength other than the common wavelength. Assume a network in which a plurality of nodes 103 including 101 and a photonic cross-connect 102 are mesh-connected. Then, the control packet is transmitted and received between the label switch routers 101 using the default optical transceiver unit 13. Using this control packet, a full mesh label switch path for each priority between the nodes 103 is set. At this time, the amount of traffic flowing through the label switch path is measured for each output port at each node 103. The label switch path with the highest priority in which the measured traffic volume per output port exceeds a preset traffic threshold is accommodated in the optical path. The optical path is released after a specified time.

  In the all-optical network performing the above operation, even when the LSP with the highest priority is accommodated in the optical path at the time when the optical path is set at the optical path start point node, the packet on the LSP with the highest priority is delayed. The time is short. Therefore, packets on the LSP are not overtaken at the optical path end point node. Alternatively, the amount of packets that can be overtaken can be minimized.

  Here, when there are a plurality of LSPs with the highest priority, the LSP accommodated in the optical path may be determined according to the attributes of the LSP other than the priority. The LSP attribute other than the priority may be the number of LSP node hops.

  Furthermore, when there are a plurality of LSPs with the highest priority, it is conceivable that a plurality of LSPs are combined into a single tunnel LSP by pushing a label and then accommodated in an optical path. In this case, the label switch function unit 14 executes label push and pop.

  Thus, according to the present invention, when switching the transfer of labeled packets from the LSP to the optical path, a packet transmission system that does not increase the delay without changing the order of the labeled packets is realized. Is possible.

  In addition, this invention is not limited to the said embodiment, In the implementation stage, it can embody by modifying a component in the range which does not deviate from the summary. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment.

1 is a system diagram showing an embodiment of a packet transmission system according to the present invention. The figure explaining the accommodation relationship of LSP and the optical path in the nodes 103-1, 103-2, and 103-3 of FIG. The functional block diagram which shows one Embodiment of the node apparatus concerning this invention.

Explanation of symbols

  101 (101-1 to 101-5) ... label switch router, 102 (102-1 to 102-5) ... photonic cross-connect (PXC), 103 (103-1 to 103-5) ... node, 11 ... light Matrix switch, 12 ... DMUX, 13 ... Default optical transceiver unit, 14 ... Label switch function unit, 15 ... Wavelength variable transceiver unit, 16 ... Router unit, 17 ... Release control unit, 18 ... LSP priority identification unit, 19 ... Traffic measurement , 20 ... Optical matrix switch control unit, 104 ... Optical transmission line, 105, 203 ... Optical path, 201 ... Low priority LSP, 202 ... High priority LSP

Claims (3)

A plurality of nodes, a first network that transfers a labeled packet through a plurality of label switch paths set between an output port of each of the plurality of nodes and an arbitrary node, and a cut-through optical path In a packet transmission system comprising a second network that can be set between a plurality of nodes,
Priority giving means for individually giving priority to the labeled packet and inserting the higher priority packet into a label switch path with a shorter transmission delay;
Traffic measuring means for measuring packet traffic transferred through the plurality of label switch paths for each output port ;
Path setting means for setting the optical path in the second network when packet traffic measured by the traffic measuring means exceeds a predetermined threshold;
A packet transmission system comprising: traffic shifting means for preferentially transferring the traffic of the label switch path for transferring the labeled packet having a high priority to the optical path set by the path setting means. When there are a plurality of label switch paths to be transferred to the optical path, the traffic shift means selects one label switch path based on at least one of the attributes of the number of node hops, the transmission distance, and the transmission band. The packet transmission system according to claim 1, wherein the selected label switch path is shifted to the optical path . 2. The apparatus according to claim 1, further comprising a label stack unit that aggregates the plurality of label switch paths into one label switch path when there are a plurality of label switch paths to be transferred to the optical path. Packet transmission system.

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