JP2014096699A - Setting method and setting device for preferential route in optical packet switch network - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a setting method and a setting device for a preferential route in an optical packet switch network which can satisfy both low delay time and setting for a preferential route in an optical packet.SOLUTION: When preferential label information is set to an output port of a preferential route information table (S3), an exclusive processing in which an optical packet only is outputted to an output port is performed until arrival of an optical packet having the preferential label information is completed (S4) and the exclusive processing is cancelled when the arrival of the optical packet is completed (S6). When there is an optical packet following the optical packet (S7), the arrival time of the following optical packet is predicted on the basis of occupied band information. After the exclusive processing is resumed before the predicted arrival time (S8), when the arrival of the following optical packet is completed, the exclusive processing is cancelled, and resuming and cancelling of the exclusive processing is repeated until the arrival of the last optical packet is completed.

Description

  The present invention relates to a setting method and a setting device for setting a priority route for preferentially switching an optical packet having specific label information in an optical packet switch network used in optical information communication or the like.

  Optical communication has the features of large capacity and ultra-high speed, and has been put into practical use in many information communication networks in recent years. The route configuration of such an optical communication network has the simplest point-to-point connection that connects two points with individual optical fibers. On the other hand, it has been proposed to switch a light signal at each node by accommodating a plurality of paths in one optical fiber by utilizing the large capacity of the optical fiber. For example, in optical path switching, the wavelength of an optical signal can be associated with a path, and the path can be switched for each wavelength using an arrayed waveguide grating (AWG), a wavelength selective optical switch (WSS), or the like. . However, the number of paths is limited by the number of wavelengths that can be set.

  Furthermore, optical packet switching (OPS) that switches paths in units of optical packets has been proposed. In this method, label information is added to each optical packet to correspond to the path, the label information is recognized at each node, and the optical packet is switched to a path according to the label information using an optical switch or the like. Since this method can increase the number of paths without being restricted by the number of wavelengths, a more flexible network can be constructed.

FIG. 5A shows an outline of a conventional optical packet switch network, and FIG. 5B shows an outline of a conventional node. In the conventional optical packet switch network 50, a plurality of nodes 60 are connected using a plurality of optical fibers 51. Each node 60 includes N input ports 61 (input ports 61 _{1 to} 61 _N ), N label processors 62 (label processors 62 _{1 to} 62 _N ), a scheduler 63, an optical switch 64, a shared buffer 65, It is composed of _N output ports 61 (output ports 66 _{1 to} 66 _N ), and is connected to another node 60 by _N input ports 61 _{1 to} 61 _N and N output ports 66 _{1 to} 66 _N. ing. N is a natural number of 1 or more.

For the optical packet (header + payload) input from a certain input port 61, first, the label information of the header is recognized by the label processors 62 _{1 to} 62 _N and the label information is sent to the scheduler 63. The scheduler 63 has a transfer information table for associating label information with the output ports 66 _{1 to} 66 _N, and determines a desired output port 66 _i (i is a natural number of 1 to N) from this label information. If necessary, the label information of the optical packet input by the label processors 62 _{1 to} 62 _N is rewritten with the label information for output. Furthermore, the scheduler 63 sends a control signal to the optical switch 64 switches the optical switch 64 so that the input optical packet output from a desired output port 66 _i. Accordingly, since the optical packet is not electrically buffered, it is switched with a short delay time.

Since the scheduler 63 knows the occupancy status of each of the output ports 66 _{1 to} 66 _N , for example, when the desired output port 66 _i is occupied by the first optical packet, for the purpose of collision avoidance, The incoming optical packet is sent to the shared buffer 65, given a delay for a required time, and after the occupied state is eliminated, it is output from the desired output port 66 _i via the optical switch 64. In this way, each node 60 can switch the optical packet efficiently and without collision using the label information added to the optical packet.

  On the other hand, with the advancement of networks, there is a demand for making a difference in transfer processing or guaranteeing bandwidth according to the quality of communication service (QoS). For example, text data transmission services such as e-mail do not need to be transmitted in real time, but video distribution services are strongly required to have real-time properties, and optical packet transmission delays and omissions (losses) that cause dropped frames are not possible. It is necessary to reduce as much as possible. Therefore, prioritization according to QoS is required for each optical packet or optical packet group.

Y. Suzaki et al., "Hybrid Optoelectronic Router for Optical Packet Switching", 15th OptoElectronics and Communications Conference (OECC2010) Technical Digest, pp. 538-539, 2010

  However, the conventional optical packet switch network as described above has the following problems.

At almost the same time, a specific node is attached with label information that an optical packet with a lower priority arrives first, an optical packet with a higher priority arrives later, and both optical packets are output to the same output port. Suppose that In this case, as described above, the label information is recognized by the label processors 62 _{1 to} 62 _N and processed from the first optical packet sent to the scheduler 63, so that the second optical packet is the first one. Even if the priority is higher than that of the optical packet, it is transferred to the shared buffer 65 to avoid collision. As a result, the optical packet having a higher priority is delayed, and the requested QoS cannot be realized.

  For example, even if the priority of the optical packet including the text data of the mail that is less affected by the delay is set lower and the priority of the optical packet including the video data that is affected by the delay is set higher, the conventional optical packet as described above is used. In the switch network, a delay is given to the optical packet including the video data, and the video may be disturbed on the receiving side.

  In order to solve these problems, it is conceivable that an input buffer or an output buffer is arranged on the input side or the output side to be electrically buffered and output from the buffer in order from the optical packet having the highest priority. However, since all optical packets need to be electrically buffered, a large-capacity buffer is required, the delay time due to electrical processing is increased, and the device configuration is complicated, resulting in an increase in cost. .

  Therefore, it has been difficult to achieve both the setting of the priority route of the optical packet and the low delay time in the optical packet switch network.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a priority route setting method and setting device in an optical packet switch network that can achieve both the setting of a priority route of an optical packet and a low delay time. .

A method for setting a priority route in the optical packet switch network according to the first invention for solving the above-described problems is as follows.
In an optical packet switch network that performs communication of a plurality of optical packets via a plurality of paths formed by connecting a plurality of nodes with a plurality of optical fibers, a setting method for setting a priority path of the optical packet switch network. And
For each optical packet, label information indicating a route through which the optical packet passes, subsequent information indicating presence / absence of an optical packet following the optical packet, and occupied band information indicating a band occupied by the optical packet are set. And transmitting the optical packet,
In each of the nodes, a priority route information table that defines the relationship between the output port of the node and priority label information that is label information of the priority route is set.
When the priority label information is registered at any output port of the priority route information table, only the optical packet having the priority label information is completed until the arrival of the optical packet having the priority label information as the label information is completed. Is output to the arbitrary output port, and when the arrival of the optical packet having the priority label information is completed, the exclusive process is canceled,
When it is determined that there is an optical packet following the optical packet having the priority label information based on the subsequent information, an arrival time of the subsequent optical packet is predicted based on the occupied band information, and the expected arrival time After the exclusive process is resumed before the arrival of the subsequent optical packet, the exclusive process is canceled and the exclusive process is restarted and released until the arrival of the last optical packet is completed. Features.

The priority route setting method in the optical packet switch network according to the second invention for solving the above-mentioned problems is as follows:
In the priority route setting method in the optical packet switch network according to the first invention,
When there is no optical packet following the optical packet having the priority label information, or when the subsequent optical packet does not arrive after the expected arrival time, the priority label set for the arbitrary output port It is characterized by deleting information.

A method for setting a priority route in an optical packet switch network according to a third invention for solving the above-described problem is as follows.
In the priority route setting method in the optical packet switch network according to the first or second invention,
When setting of the priority route is requested, the priority label information is transmitted to the node corresponding to the priority route using at least one network controller that transmits information to each of the nodes. .

An apparatus for setting a priority route in an optical packet switch network according to a fourth invention for solving the above-described problems,
In an optical packet switch network that performs communication of a plurality of optical packets via a plurality of paths formed by connecting a plurality of nodes with a plurality of optical fibers, the setting device sets a priority path of the optical packet switch network. And
Each of the nodes has control means for setting processing of the optical packet based on label information indicating a route through which the optical packet set in the optical packet passes,
The control means includes
Set the priority route information table that defines the relationship between the output port of the node and the priority label information that is the label information of the priority route,
When the priority label information is registered at any output port of the priority route information table, only the optical packet having the priority label information is completed until the arrival of the optical packet having the priority label information as the label information is completed. Is output to the arbitrary output port, and when the arrival of the optical packet having the priority label information is completed, the exclusive process is canceled,
When it is determined that there is an optical packet subsequent to the optical packet having the priority label information based on subsequent information indicating the presence or absence of an optical packet subsequent to the optical packet set in the optical packet, the optical packet is set. The arrival time of the subsequent optical packet is predicted based on the occupied bandwidth information indicating the band occupied by the optical packet, and the exclusion process is resumed before the expected arrival time, and then the arrival of the subsequent optical packet Is completed, the exclusion process is released, and the exclusion process is restarted and released until the arrival of the last optical packet is completed.

A priority route setting device in an optical packet switch network according to a fifth invention for solving the above-mentioned problems,
In the priority route setting device in the optical packet switch network according to the fourth invention,
The control means includes
If there is no optical packet that follows the optical packet having the priority label information, or if the subsequent optical packet does not arrive after the expected arrival time, it is sent to the arbitrary output port of the priority route information table. The set priority label information is deleted.

A priority route setting device in an optical packet switch network according to a sixth invention for solving the above-described problems,
In the priority route setting device in the optical packet switch network according to the fourth or fifth invention,
Comprising at least one network controller for transmitting information to each said node;
The network controller
When setting of the priority route is requested, the priority label information is transmitted to the control means of the node corresponding to the priority route.

  According to the present invention, in an optical packet switch network, a low priority optical packet arrives first at a specific node at approximately the same time, a high priority optical packet arrives later, and both optical packets have the same output port. Even if the label information to be output to is added, it is possible to preferentially output the optical packet having a high priority from the desired output port without electrically buffering all the optical packets. As a result, it is possible to achieve both the setting of the priority route of the optical packet and the low delay time.

It is a figure which shows an example of embodiment of the setting apparatus of the priority path | route in the optical packet switch network which concerns on this invention, (a) is a schematic block diagram of the optical packet switch network, (b) is the node. It is a schematic block diagram shown. It is a figure explaining the information table set to the node shown in FIG.1 (b), (a) shows the state which registered the priority route information in the output port number 4, (b) shows the output port number. FIG. 6 is a diagram illustrating a state where priority route information 4 is deleted. 2 is a flowchart for explaining a setting procedure performed in the optical packet switch network and the node shown in FIGS. FIGS. 1A and 1B are time charts illustrating a setting procedure performed in the optical packet switch network and the node illustrated in FIGS. 1A and 1B, where FIG. 1A is set when priority route information is set and FIG. After setting the route information, (c) is the arrival of the optical packet P ₁ , (d) is the arrival of the optical packet P ₁ , (e) is the arrival and arrival of the optical packet P _L-1 , (F) is when the optical packet P _L arrives. (A) is a schematic block diagram which shows the conventional optical packet switch network, (b) is a schematic block diagram which shows the node.

  Hereinafter, with reference to FIGS. 1 to 4, a preferred route setting method and setting apparatus in an optical packet switch network according to the present invention will be described.

Example 1
First, referring to the schematic configuration diagram of the optical packet switch network and nodes shown in FIGS. 1A and 1B and the schematic configuration diagram of the information table shown in FIG. 2, the optical packet switch network of this embodiment will be described. The configuration of the node will be described.

The optical packet switch network 10 (hereinafter referred to as OPSN 10) of the present embodiment connects five nodes 20 (nodes 20 _{1 to} 20 ₅ ) with a plurality of optical fibers 11 as shown in FIG. forms Te, a plurality of paths is formed between the nodes 20 ₁ to 20 ₅ are connected to node 20 ₁ to 20 ₅ with each other. For example, between the server S1 connected to the node 20 ₁ by the optical fiber 11 and the server S2 connected to the node 20 ₅ by the optical fiber 11, for example, the node 20 ₁ → the node 20 ₂ → the node 20 ₃ , the node A plurality of paths such as 20 ₁ → node 20 ₄ → node 20 ₃ , node 20 ₁ → node 20 ₅ → node 20 ₃ are formed. When information consisting of a plurality of optical packets is communicated between the server S1 and the server S2, a plurality of optical packets are communicated via at least one of these paths.

Each of the nodes 20 _{1 to} 20 ₅ is connected to one network controller (hereinafter referred to as NC) 30. The NC 30 manages label information indicating a transfer route, a priority route, and the like, and transmits label information and priority route information (priority label information) to be set in each of the nodes 20 _{1 to} 20 ₅ .

  Here, as an example, the number of nodes 20 is five and the number of NCs 30 is one. However, the number of nodes 20 and NCs 30 is not limited. What is necessary is just to operate in cooperation.

  Each optical packet basically includes a header and a payload. The header includes at least label information indicating a transfer path through which the optical packet passes, and subsequent information indicating the presence or absence of an optical packet following the optical packet. And occupied band information indicating a band occupied by the optical packet (or interval information indicating an interval between optical packets following the optical packet) is set. In the payload, main information, for example, information such as text data and video data is set. These pieces of information are set by, for example, the servers S1 and S2.

Each node 20 includes N input ports 21 (input ports 21 _{1 to} 21 _N ) and N label processors 22 (label processors 22 _{1 to} 22) as shown in FIG. _N ), a scheduler 23 (control means), an optical switch 24, a shared buffer 25, and N output ports 26 (output ports 26 _{1 to} 26 _N ). N input ports 21 _{1 to} 21 _N and N output ports 26 _{1 to} 26 _N are connected to another node 20. N is a natural number of 1 or more.

The label processors 22 _{1 to} 22 _N recognize the header information of the optical packet input from the other nodes 20 via the input ports 21 _{1 to} 21 _N and send the recognized information to the scheduler 23.

The scheduler 23 includes an information table 40. The information table 40 includes at least a transfer information table 41 indicating a correspondence relationship between the label information corresponding to the transfer route route and the output ports 26 _{1 to} 26 _N of the node 20. When, the output port utilization information table 42 indicating the current usage of the output ports 26 ₁ ~ 26 _N, the relationship between the label information of the output port 26 ₁ ~ 26 _N and priority path of the node 20 (priority label information) The priority route information table 43 shown in FIG. In the transfer information table 41 and the priority route information table 43, label information and priority route information (priority label information) transmitted from the NC 30 are set.

Specifically, as shown in FIG. 2A, the transfer information table 41 includes label information “Label 1”, “Label 2”,... Transmitted from the NC 30, and output ports 26 ₁ to 26 of the node 20. The relationship with _N is specified. The priority route information table 43 defines the relationship between the output ports 26 _{1 to} 26 _{N of the} node 20 and the priority route information “Label 1”, “Label 2”, etc. transmitted from the NC 30. For example, The port number “2” is set to “Label1”, and the port number “4” is set to “Label2”. Note that the label “0” in the port numbers “1”, “3”, etc. means that the priority route information is not set.

Further, as shown in FIG. 2A, the output port usage information table 42 shows the usage status of the output ports 26 _{1 to} 26 _N of the node 20, for example, port numbers “1”, “ The usage “0” in “3” and the like indicates a situation where it is not used, and the usage “1” in the port numbers “2” and “4” indicates a situation where it is being used.

Note that the output port number “4” in the output port usage information table 42 and the priority route information table 43 shown in FIG. 2A indicates the route of the node 20 ₁ → the node 20 ₂ → the node 20 ₃ as the priority route. set at node 20 ₂ when set is shown as an example.

The scheduler 23 collates the information of the header of the optical packet sent from the label processors 22 _{1 to} 22 _N with the transfer information table 41 and determines a desired output port 26 _i (i is a natural number of 1 to N). Then, a control signal for selecting the determined port number is sent to the optical switch 24, and the optical switch 24 is switched. As a result, the input optical packet is output from the desired output port 26 _i .

  The priority route is set when it is desired to transmit an optical packet or an optical packet group between specific nodes 20 with low delay and no packet loss.

  Next, together with FIGS. 1A, 1B, 2A, and 2B, a flowchart for setting the priority route shown in FIG. 3, and the priority route setting shown in FIGS. A method for setting a priority route will be described with reference to a time chart.

Here, when transferring the light packets from the server S1 to the server S2, the connection route through the node 20 ₂ from the node 20 ₁ to node 20 _3, a method for setting a priority path. Since the operation of each of the nodes 20 _{1 to} 20 ₃ is almost the same, only the node 20 ₂ will be described here. Further, it is assumed that the input port 26 ₄ and an output port 26 _fourth node 20 ₂ is connected to the node 20 _3.

(Step S1)
First, the server S1 is a set request for which you want to send the optical packet group sets the priority route to the server S2, via a node 20 ₁ which server S1 is connected, performed NC30.

(Step S2)
When there is a priority route setting request, the NC 30 determines a priority route based on the configuration of the OPSN 10 and transmits priority route information (priority label information) corresponding to the priority route to each node 20 on the priority route.

For example, here, the fact that the label information “Label 2” is set as the priority route is transmitted to the nodes 20 _{1 to} 20 ₃ . This label information is actually expressed as a 16-bit binary number (for example, 1111000011110010), but here it is expressed as “Label2” for convenience. Note that the number of bits of label information is not particularly limited as long as the number of necessary paths can be expressed, and may be 8 bits or 32 bits.

(Step S3)
In each of the nodes 20 _{1 to} 20 ₃ on the priority route, the priority route information transmitted from the NC 30 is collated with the transfer information table 41, the output port 26 corresponding to the priority route information is confirmed, and the priority route information table Priority route information is set to 43 corresponding output ports 26.

For example, as shown in FIG. 2 (a), the node 20 _2, from the transfer information table 41 to check the output port number "4" corresponding to the priority path information "Label2", the output of the priority route information table 43 “Label2” is set to the port number “4”. The time when this setting is performed is time T ₀ shown in FIG. Then, at this time T ₀ , the usage status “1” is set to the output port number “4” of the output port usage information table 42.

At this time, the server S1 waits for a predetermined transmission waiting time (for example, 10 ms) until the setting in each of the nodes 20 _{1 to} 20 ₃ on the priority route is completed, and then transmits a continuous optical packet group. At this time, the label information of these optical packet groups is “Label2”, the occupied bandwidth information is “1/5”, the information on the presence / absence of the subsequent optical packet is “present” except for the final optical packet, and the final optical packet is “None”.

  Since the transmission waiting time of the optical packet group strongly depends on the configuration of the OPSN 10, an optimal value may be set for each OPSN 10 or a maximum value assuming the worst case may be set. The actual occupied bandwidth information is expressed in binary numbers (for example, 0010) and can be arbitrarily set according to the service level of the OPSN 10. For example, when the occupied band is expressed as 1 / M (M is 1 to 15) in fractions and the value of M is expressed in binary 4-bit notation, 100% is occupied when M = 1, and 20 when M = 5. % Occupancy. In addition, the presence / absence information of the actual subsequent packet is expressed in binary number (for example, 1), and may be 1 if there is a subsequent, and 0 if there is no subsequent.

  These pieces of information are written in the header of each optical packet, and transmitted from the server S1 at intervals according to the occupied bandwidth. For example, if the transmission speed is 10 Gb / s, the maximum packet length is 1500 bytes, and the occupied bandwidth is 1/5 (= 20%; 1.2 μs). Therefore, the interval of 4.8 μs corresponding to the remaining 80% is set. Send an optical packet after empty.

(Step S4)
As shown in FIG. 4B, exclusive processing is set for each of the nodes 20 _{1 to} 20 ₃ from the time T ₀ to the fixed time Ta ₀ . In this exclusive processing, the optical packet having the priority route information is output to the output port 26 for the output port 26 in which the priority route information is set, and all other optical packets are transferred to the shared buffer 25 or discarded. Like to do. This is a process for outputting the first optical packet of the optical packet group having the priority route information to the desired output port 26 without collision.

(Step S5)
When an optical packet is input to each of the nodes 20 _{1 to} 20 ₃ , information on the header of this optical packet, specifically, label information added to the header, information on the presence / absence of a subsequent packet, and information on occupied bandwidth are obtained. The optical packet received by the scheduler 23 is processed based on the recognized label information recognized by the label processor 22.

For example, when an optical packet having other label information directed to the output port number “4” (output port 26 ₄ ) reaches the label processor 22 of the node 20 ₂ , the label information is identified and transferred to the scheduler 23. Is done. The scheduler 23 collates with the output port usage information table 42 and, as described above, the usage status “1” is set to the output port number “4” of the output port usage information table 42 at time T ₀ . The exclusive processing is performed, and the data is transferred to the shared buffer 25 and buffered or discarded. For example, when an optical packet having “Label5” is input, in the normal process, it is output to the output port number “4”. However, while the exclusive process is being performed, the output port number “4” is output. Instead, it is transferred to the shared buffer 25 or discarded.

On the other hand, when the first optical packet P ₁ of the optical packet group having the priority route information reaches the label processor 22 of the node 20 ₂ , the label information is identified and transferred to the scheduler 23. In the scheduler 23, the label information is checked against the transfer information table 41 to determine the output port number of the output port 26, and then checked against the priority route information table 43 to confirm that it is the priority route information. Therefore, unlike the optical packet having other label information, the packet is output unconditionally to the output port 26 in which the priority route information is set without checking the output port usage information table 42. For example, the _first optical packet P ₁ having the label information “Label 2” is output to the output port number “4”.

(Step S6)
At time Tb ₁ when the arrival of the _first optical packet P ₁ having the priority route information is completed, as shown in FIG. 4C, the exclusive processing for the output port 26 in which the priority route information is set is canceled. At this time, as shown in FIG. 2B, the output port number “4” in the priority route information table 43 is set to “0”, and the output port number “4” in the output port usage information table 42 is not yet set. Usage status “0” is set.

(Step S7)
If there is a subsequent packet, the process proceeds to step S8, and if there is no subsequent packet, the process proceeds to step S9. That is, if the input optical packet is not the final optical packet of the optical packet group, the process proceeds to step S8, and then the procedure of steps S5 to S8 is repeated. If the input optical packet is the final optical packet, Proceeding to step S9, a series of procedures is completed.

(Step S8)
If there is a subsequent packet, the scheduler 23 can predict the estimated arrival time Te ₁ for the arrival of the next optical packet from the recognized occupied band information, and resumes the exclusion process from the time Td ₁ before the predetermined time. That is, as shown in FIG. 4D, during the time Tc ₁ from the time Tb ₁ when the arrival of the _first optical packet P ₁ is completed to the time Td ₁ , the exclusive process is canceled and the normal process is performed. Thus, optical packets other than optical packets having priority route information can be output from the output port 26 in which the priority route information is set.

For example, from the recognized occupied bandwidth information, when the interval between the optical packets of the optical packet group is 4.8 μs as described above, the expected arrival time Te ₁ of the next optical packet is [Te ₁ = Tb ₁ +4. .8 μs]. Then, the value of the output port number “4” in the output port usage information table 42 is not used for the time Tc ₁ = 3.6 μs shorter than the estimated arrival time Te ₁ by the maximum packet length (1.2 μs). The state is set to “0”, and after the time Td ₁ , the usage state is set to “1” again. This is a process for preventing collision with a subsequent optical packet having priority path information even when an optical packet having a maximum packet length without priority path information is input immediately before the exclusion process is resumed.

Even when the subsequent optical packet P _j (j is a natural number of 1 to _L ) arrives, until the last optical packet P _L is input, as shown in FIG. The above procedure is repeated and the same processing is performed. By performing such a procedure, when an optical packet with a high priority does not occupy the desired output port 26, other optical packets can be output from the desired output port 26, thereby avoiding overflow of the shared buffer 25. Or discarding of optical packets can be reduced.

(Step S9)
When there is no subsequent packet, that is, when the optical packet is the final optical packet P _L , as shown in FIG. 4F, when the arrival of the final optical packet P _L is completed (time Tb _L ), The priority route information is deleted from the priority route information table 43, the value of the output port number “4” in the output port usage information table 42 is deleted, and the value is set to “0” in the unused state. (See FIG. 2 (b)). As a result, the exclusion process is canceled and the priority path setting process is completed.

As an abnormal process, it is conceivable that the subsequent optical packet P _j does not arrive before the expected arrival time Te _j . As processing in this case, the following two processings are possible according to the service level of the OPSN 10.

The first is a method for holding information on priority routes as much as possible. As described above, it resumes the exclusive processing from a predetermined time before the time Td _j subsequent estimated arrival time Te _j of the optical packet P _j, or subsequent optical packet P _j from waiting to arrive, or predetermined After the timeout time elapses, it is considered that the priority route has been canceled, the exclusive process is canceled, and the priority route information is deleted from the priority route information table 43.

The second is a method of canceling according to occupied band information. As described above, when the exclusive control from a given time before the time Td _j subsequent estimated arrival time Te _j of the optical packet P _j resumed, after more than a predetermined time calculated from the occupied bandwidth information, that is, the expected arrival time Once past the Te _j, it is regarded as a priority path is canceled to release the exclusive process, and deletes the priority route information from the priority route information table 43. In the first place, the priority route is set to stably transfer a group of continuous optical packets with a low delay, and there is a possibility that the subsequent optical packet P _j will not arrive by the expected arrival time Te _j from its use. Therefore, it is reasonable to cancel the transmission side or the OPSN 10 on the assumption that some abnormality has occurred.

  The present invention is suitable for an optical packet switch network that sets a priority path for preferentially switching an optical packet having specific label information.

10 Optical packet switch network (OPSN)
20 _{1 to} 20 ₅ node 21 (21 _{1 to} 21 _N ) input port 22 (221 _{1 to} 22 _N ) label processor 23 scheduler (control means)
24 optical switch 25 shared buffer 26 (26 ₁ ~26 _N) output port 30 network controller (NC)
40 Information Table 41 Transfer Information Table 42 Output Port Usage Information Table 43 Priority Route Information Table

A method for setting a priority route in the optical packet switch network according to the first invention for solving the above-described problems is as follows.
In an optical packet switch network that performs communication of a plurality of optical packets via a plurality of paths formed by connecting a plurality of nodes with a plurality of optical fibers, a setting method for setting a priority path of the optical packet switch network. And
For each optical packet, label information indicating a route through which the optical packet passes, subsequent information indicating presence / absence of an optical packet following the optical packet, and occupied band information indicating a band occupied by the optical packet are set. And transmitting the optical packet,
In each of the nodes, a priority route information table that defines the relationship between the output port of the node and priority label information that is label information of the priority route is set.
When the priority label information is registered at any output port of the priority route information table, only the optical packet having the priority label information is completed until the arrival of the optical packet having the priority label information as the label information is completed. Is output to the arbitrary output port, and when the arrival of the optical packet having the priority label information is completed, the exclusive process is canceled,
Based on the subsequent information, when it is determined that there is an optical packet following the optical packet having the priority label information, an expected arrival time of the subsequent optical packet is predicted based on the occupied bandwidth information, and the arrival prediction After the exclusion process is resumed before time, when the arrival of the subsequent optical packet is completed, the exclusion process is canceled, and the restart and release of the exclusion process are repeated until the arrival of the last optical packet is completed. It is characterized by.

An apparatus for setting a priority route in an optical packet switch network according to a fourth invention for solving the above-described problems,
In an optical packet switch network that performs communication of a plurality of optical packets via a plurality of paths formed by connecting a plurality of nodes with a plurality of optical fibers, the setting device sets a priority path of the optical packet switch network. And
Each of the nodes has control means for setting processing of the optical packet based on label information indicating a route through which the optical packet set in the optical packet passes,
The control means includes
Set the priority route information table that defines the relationship between the output port of the node and the priority label information that is the label information of the priority route,
When the priority label information is registered at any output port of the priority route information table, only the optical packet having the priority label information is completed until the arrival of the optical packet having the priority label information as the label information is completed. Is output to the arbitrary output port, and when the arrival of the optical packet having the priority label information is completed, the exclusive process is canceled,
When it is determined that there is an optical packet subsequent to the optical packet having the priority label information based on subsequent information indicating the presence or absence of an optical packet subsequent to the optical packet set in the optical packet, the optical packet is set. based on the occupied band information indicating a band to which the optical packet occupies that is, to predict the expected arrival time of a subsequent optical packet, after resuming the exclusive process prior to the estimated arrival time, the subsequent optical packet When the arrival is completed, the exclusion process is canceled, and the exclusion process is restarted and released until the arrival of the last optical packet is completed.

Claims (6)

In an optical packet switch network that performs communication of a plurality of optical packets via a plurality of paths formed by connecting a plurality of nodes with a plurality of optical fibers, a setting method for setting a priority path of the optical packet switch network. And
For each optical packet, label information indicating a route through which the optical packet passes, subsequent information indicating presence / absence of an optical packet following the optical packet, and occupied band information indicating a band occupied by the optical packet are set. And transmitting the optical packet,
In each of the nodes, a priority route information table that defines the relationship between the output port of the node and priority label information that is label information of the priority route is set.
When the priority label information is registered at any output port of the priority route information table, only the optical packet having the priority label information is completed until the arrival of the optical packet having the priority label information as the label information is completed. Is output to the arbitrary output port, and when the arrival of the optical packet having the priority label information is completed, the exclusive process is canceled,
When it is determined that there is an optical packet following the optical packet having the priority label information based on the subsequent information, an arrival time of the subsequent optical packet is predicted based on the occupied band information, and the expected arrival time After the exclusive process is resumed before the arrival of the subsequent optical packet, the exclusive process is canceled and the exclusive process is restarted and released until the arrival of the last optical packet is completed. A preferred route setting method in an optical packet switch network. The method for setting a priority route in the optical packet switch network according to claim 1,
When there is no optical packet following the optical packet having the priority label information, or when the subsequent optical packet does not arrive after the expected arrival time, the priority label set for the arbitrary output port A method for setting a priority route in an optical packet switch network, wherein information is deleted. In the setting method of the priority path | route in the optical packet switch network of Claim 1 or Claim 2,
When setting of the priority route is requested, the priority label information is transmitted to the node corresponding to the priority route using at least one network controller that transmits information to each of the nodes. A method for setting a priority route in an optical packet switch network. In an optical packet switch network that performs communication of a plurality of optical packets via a plurality of paths formed by connecting a plurality of nodes with a plurality of optical fibers, the setting device sets a priority path of the optical packet switch network. And
Each of the nodes has control means for setting processing of the optical packet based on label information indicating a route through which the optical packet set in the optical packet passes,
The control means includes
Set the priority route information table that defines the relationship between the output port of the node and the priority label information that is the label information of the priority route,
When the priority label information is registered at any output port of the priority route information table, only the optical packet having the priority label information is completed until the arrival of the optical packet having the priority label information as the label information is completed. Is output to the arbitrary output port, and when the arrival of the optical packet having the priority label information is completed, the exclusive process is canceled,
When it is determined that there is an optical packet subsequent to the optical packet having the priority label information based on subsequent information indicating the presence or absence of an optical packet subsequent to the optical packet set in the optical packet, the optical packet is set. The arrival time of the subsequent optical packet is predicted based on the occupied bandwidth information indicating the band occupied by the optical packet, and the exclusion process is resumed before the expected arrival time, and then the arrival of the subsequent optical packet Is completed, the exclusive processing is canceled, and the exclusive processing is repeated and resumed until the arrival of the last optical packet is completed. In the priority route setting device in the optical packet switch network according to claim 4,
The control means includes
If there is no optical packet that follows the optical packet having the priority label information, or if the subsequent optical packet does not arrive after the expected arrival time, it is sent to the arbitrary output port of the priority route information table. An apparatus for setting a priority route in an optical packet switch network, wherein the set priority label information is deleted. In the priority route setting device in the optical packet switch network according to claim 4 or 5,
Comprising at least one network controller for transmitting information to each said node;
The network controller
An apparatus for setting a priority route in an optical packet switch network, wherein when priority route setting is requested, the priority label information is transmitted to the control means of the node corresponding to the priority route.

Images