JP3850326B2 - Traffic monitoring server device, traffic engineering system, and traffic engineering method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a traffic monitoring server device, a traffic engineering system, and a traffic engineering method for comprehensively controlling bandwidth guaranteed traffic and non-bandwidth guaranteed traffic in a label switch network.
[0002]
[Prior art]
MPLS (Multiprotocol Label Switching) is known as a technique for accelerating packet transfer by adding label information instead of IP address information to IP packet transfer. A network to which this MPLS is applied is disclosed in the document “Multiprotocol Label Switching Architecture” (downloadable as rfc3031.txt from http://www.ietf.org). In traffic engineering in a network to which MPLS is applied, a label switch path (LSP) that passes through a plurality of different paths between an ingress label edge router and an egress label edge router is intended for effective use of network resources. Various processing is performed, for example, depending on network congestion, traffic is distributed to the label switch path that passes through the non-congested link, or the label switch path that passes through the non-congested link is added It is a process to set. For example, the document “RSVP-TE: Extensions to RSVP for LSP Tunnels” (http://www.ietf.org has draft-ietf-mpls-rsvp-lsp-tunnel-09.txt RSVP (Resource Reservation Setup Protocol) -TE (Traffic Engineering) or the like as a signaling protocol described in (Downloadable) is used.
[0003]
Also, in the conventional traffic engineering (TE), by collecting information such as reserved bandwidth and used bandwidth for the link between routers as a target unit, a link causing congestion is avoided and traffic is sent to an empty link. A method of distributing the load is adopted. For example, a method in which a plurality of label switch paths having different routes are set in advance, and an ingress label edge router distributes traffic trunks between label switch paths so as to reduce congestion according to the congestion of the link through which the label switch path passes. Has been recently studied (Japanese Patent Laid-Open No. 2001-251343).
[0004]
[Problems to be solved by the invention]
In the above prior art, congestion is determined only by traffic information (traffic statistical information) observed in units of links on the network. That is, in the prior art, the traffic congestion state focusing on the inside of the label switch on the network is not observed. For this reason, conventionally, there is a problem in that the presence or absence of bandwidth guarantee required for traffic cannot be correctly reflected in traffic engineering. Hereinafter, this problem will be described in detail.
[0005]
For example, if you use a Best Effort label switch path as a label switch path without bandwidth guarantee (non-bandwidth guaranteed label switch path), all traffic on the link that it traverses will cause the traffic of interest. Since the performance is affected, there is no problem with the conventional method based on the link observation described above. However, in the case of using a band-guaranteed type label switch path in combination, it cannot be determined whether or not the link is really a disadvantageous link for band-guaranteed traffic only by the congestion state observed in units of links. It may happen that best-effort traffic is fully using the link and that it can actually flow into the guaranteed bandwidth label switch path set up on that link. Because there is no. Traffic engineering that cannot determine this correctly and redirects bandwidth-guaranteed traffic to other label switch paths that pass through other links, or encourages the addition of new label switch paths, clearly There is a risk of causing unnecessary operations.
[0006]
The present invention has been made in consideration of the above circumstances, and its purpose is to control network resources by controlling each allocation in an integrated manner so as to optimize the performance of bandwidth guaranteed traffic and non-bandwidth guaranteed traffic. It is an object of the present invention to provide a traffic monitoring server device, a traffic engineering system, and a traffic engineering method that can be used effectively.
[0007]
Another object of the present invention is to provide a traffic monitoring server device, a traffic engineering system, and a traffic engineering method capable of effectively utilizing network resources by adjusting reserved bandwidths when congestion is not eliminated only by traffic distribution. There is to do.
[0008]
[Means for Solving the Problems]
According to the first aspect of the present invention, a label that forms a detour path between a first label edge router serving as a starting point of one core network constituting a label switch network and a second label edge router serving as an end point. A plurality of band-guaranteed label switch paths including a switch path and a plurality of non-bandwidth-guaranteed label switch paths including a label switch path forming a detour path are set, and at least one of the set label switch paths is at least A traffic monitoring server device applied to a traffic engineering system relayed by one label switch router is provided. The traffic monitoring server device includes first traffic monitoring means for obtaining traffic information in units of links from the at least one label switch router, and traffic information and reserved bandwidth information in units of label switches from the at least one label switch router. Second traffic monitoring means for acquiring the first traffic determination means, first congestion determination means for determining the congestion status of the non-bandwidth-guaranteed label switch path based on the traffic information acquired by the first traffic monitoring means, and the first Congestion by the second congestion determination means for determining the congestion status of the bandwidth-guaranteed label switch path based on the traffic information and reserved bandwidth information acquired by the traffic monitoring means of 2 and the congestion by the first or second congestion determination means Non-bandwidth guaranteed traffic or bandwidth protection based on the status judgment result Type traffic and a control request means for notifying the traffic control request to make distributed to optimum label switched path by the first label edge router to the first label edge router.
[0009]
In the traffic monitoring server device according to the first aspect, the traffic information targeted for the link between the routers, the reserved bandwidth and the traffic information targeted for each label switch path (LSP) passing over the link, Collected, congestion in units of links and congestion in units of label switch paths are determined, and based on the determination result, distribution of each of the bandwidth guarantee type traffic and the non-bandwidth guarantee type traffic is controlled in an integrated manner.
[0010]
As described above, for bandwidth guaranteed traffic, load distribution of bandwidth guaranteed flow can be achieved by using the traffic information of each label switch path for congestion determination. In addition, for non-bandwidth guaranteed traffic, by using traffic information on a per-link basis for congestion judgment, it is possible to appropriately distribute the flow load considering the characteristics that the non-bandwidth guaranteed type is affected by IP traffic other than the label switch path. . As a result, the performance of bandwidth guaranteed traffic and non-bandwidth guaranteed traffic can be optimized, and network resources can be used effectively.
[0011]
Here, according to the traffic distribution control to the first label edge router by the control request unit, the bandwidth guaranteed traffic distribution based on the congestion state determination result by the second congestion determination unit is the congestion state by the first congestion determination unit. If the configuration is prioritized over the distribution of non-bandwidth guaranteed traffic based on the judgment result, the performance of the non-bandwidth guaranteed traffic that is more important to the user is maximized, and the non-bandwidth guaranteed traffic also stably provides high performance. It becomes possible. To prioritize the allocation of bandwidth guaranteed traffic over the allocation of non-bandwidth guaranteed traffic, execute traffic information acquisition for each link at the first time interval to acquire traffic information and reserved bandwidth information for each label switch path. It is good to carry out in the 2nd time interval shorter than the said 1st time interval.
[0012]
The traffic monitoring server device according to the second aspect of the present invention is configured so that the congestion of the bandwidth-guaranteed label switch path is not eliminated even by the traffic distribution by the first label edge router based on the control of the control request means. A reserved bandwidth calculating means for receiving a request for changing a reserved bandwidth notified from one label edge router and calculating a value of a reserved bandwidth that can be increased for a bandwidth-guaranteed label switch path that does not eliminate the congestion; It further comprises a reserved bandwidth change requesting means for requesting the first label edge router to change to the value of the increaseable reserved bandwidth calculated by the calculating means.
[0013]
In the traffic monitoring server device according to the second aspect of the present invention, even when congestion is not eliminated only by traffic distribution, the congestion is eliminated by adjusting the reserved bandwidth, and network resources can be used more effectively. .
[0014]
It should be noted that the present invention relating to the above-described traffic monitoring server apparatus is established as an invention relating to a traffic engineering system provided with the traffic monitoring server apparatus or an invention relating to a traffic engineering method applied in the traffic engineering system. Further, the present invention relating to the traffic monitoring server apparatus is also established as an invention relating to a program (traffic monitoring program) for causing a computer to execute a processing procedure applied in the traffic monitoring server apparatus.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram showing a schematic configuration of a traffic engineering system according to an embodiment of the present invention.
[0016]
The traffic engineering system of FIG. 1 mainly includes a traffic monitoring server (traffic monitoring server device) TMS, a pair of label edge routers LER1 and LER3, and at least one label switch router, for example, three label switch routers LSR1 and LSR2. And LSR3, a plurality of best-effort label switch paths as non-bandwidth-guaranteed label switch paths, eg, two best-effort label switch paths LSP1 and LSP2, and a plurality of bandwidth-guaranteed label switch paths, eg, 2 It is composed of two band-guaranteed type label switch paths LSP3 and LSP4. The best effort type label switch paths LSP1 and LSP2 and the band guaranteed type label switch paths LSP3 and LSP4 include a label switch path forming a detour.
[0017]
The label edge router LER1 is an entrance label edge router of one core network constituting the label switch network (MPLS network), and the label edge router LER3 is an exit label edge router of the core network. The ingress label edge router LER1 can be an egress label edge router of another core network constituting the label switch network. Similarly, the egress label edge router LER3 can be an ingress label edge router of another core network constituting the label switch network.
[0018]
The label edge router LER1 is connected to the port P11 of the label switch router LSR1 by a cable C1. The port P12 of the label switch router LSR1 is connected to the port P21 of the label switch router LSR2 by a cable C2. The port P22 of the label switch router LSR2 is connected to the port P31 of the label switch router LSR3 by a cable C3. The port P13 of the label switch router LSR1 is connected to the port P32 of the label switch router LSR3 by a cable C4. The port P33 of the label switch router LSR3 is connected to the exit label edge router LER3 by a cable C5. A physical path realized by each cable Ci (i = 1 to 5), that is, a physical path between routers on the label switch network (inner core network) is called a link.
[0019]
In the example of FIG. 1, the best effort type label switch path LSP1 and the bandwidth guarantee type label switch path LSP3 are interposed between the ingress label edge router LER1 and the egress label edge router LER3 via the label switch routers LSR1 and LSR3. The best effort type label switch path LSP2 and the band guarantee type label switch path LSP4 are set through the label switch routers LSR1, LSR2, and LSR3.
[0020]
The traffic monitoring server TMS centrally manages traffic information of the entire label switch network, and performs integrated traffic control and resource control. However, in this embodiment, in order to simplify the description, it is assumed that traffic information in the core network shown in FIG. 1 is centrally managed by the traffic monitoring server TMS, not the entire label switch network. In this embodiment, the traffic monitoring server TMS is provided independently of the label edge routers LER1 and LER3 and the label switch routers LSR1, LSR2 and LSR3, but is provided in any of the routers. A configuration is also possible.
[0021]
FIG. 2 shows a block configuration of the traffic monitoring server TMS. As shown in the figure, the traffic monitoring server TMS includes traffic monitoring units 201 and 202, congestion determination units 203 and 204, a control request unit 205, a reserved bandwidth calculation unit 206, and a reserved bandwidth change request unit 207. Composed. The functions of these units 201 to 207 are realized by the CPU reading and executing a predetermined traffic monitoring program recorded on a recording medium such as a CD-ROM or downloaded to a storage device such as a hard disk device via a network. It is also possible to do.
[0022]
The traffic monitoring unit 201 periodically monitors each label switch router LSRj (j = 1 to 3) on the label switch network (core network), and acquires traffic information for each link. The traffic monitoring unit 202 periodically monitors each label switch router LSRj on the label switch network (core network), and acquires traffic information for each label switch path. The traffic monitoring unit 202 also acquires reserved bandwidth information for the bandwidth-guaranteed label switch path.
[0023]
The congestion determination unit 203 analyzes the link unit traffic information acquired by the traffic monitoring unit 201, and determines the presence or absence of congestion based on the determination result (threshold) of the best effort type label switch path based on the analysis result. . The congestion determination unit 204 analyzes the traffic information of the label switch path acquired by the traffic monitoring unit 202, and based on the analysis result, the presence / absence of congestion is determined based on the determination criterion (threshold) of the band-guaranteed label switch path. judge.
[0024]
When it is determined by the congestion determination unit 203 or the congestion determination unit 204 that there is congestion, the control request unit 205 sends a control request (traffic control request) for distribution of best effort type traffic or bandwidth guaranteed type traffic to an entrance label. The edge router LER1 is notified.
[0025]
When receiving the “alert” from the ingress label edge router LER1, the reserved bandwidth calculation unit 206 calculates a free bandwidth on the network and calculates a value that can increase the reserved bandwidth of the bandwidth-guaranteed label switch path.
[0026]
The reserved bandwidth change request unit 207 notifies the label edge router LER1 of the value calculated by the reserved bandwidth calculator 206 as a reserved bandwidth change request. The reserved bandwidth change request unit 207 also returns the reserved bandwidth to the original state when the congestion determination unit 204 determines that the congestion has been eliminated for the bandwidth-guaranteed label switch path that has once increased the reserved bandwidth. The label edge router LER1 is notified as a reserved bandwidth change request.
[0027]
As described above, the label edge routers LER1 and LER3 are the label edge routers at the entrance and exit of the core network, respectively. FIG. 3 shows a block configuration of the ingress label edge router LER1 related to the present invention. As shown in the figure, the ingress label edge router LER1 includes an LSP setting unit 301, a traffic distribution unit 302, a congestion determination unit 303, an alert notification unit 304, and a reserved bandwidth changing unit 305. Each of the label edge routers LER1 and LER3 functions as both routers so that it can be used as an ingress label edge router or an egress label edge router.
[0028]
The LSP setting unit 301 sets a plurality of label switch paths (LSP) between the ingress label edge router LER1 and the egress label edge router LER3.
[0029]
When a traffic control request is notified from the traffic monitoring server TMS (inside the control request unit 205), the traffic distribution unit 302 refers to the content of the traffic control request and determines each of the best effort type traffic and the bandwidth guaranteed type traffic. Assign to the label switch path.
[0030]
The congestion determination unit 303 determines whether or not congestion has been eliminated as a result of the distribution of bandwidth guaranteed traffic by the traffic distribution unit 302.
The alert notification unit 304 notifies the traffic monitoring server TMS of “alert” as warning information for requesting a change value of the reserved bandwidth when the congestion is not eliminated even if the bandwidth guaranteed traffic is distributed.
[0031]
The reserved bandwidth changing unit 305 changes the reserved bandwidth of the bandwidth-guaranteed label switch path when a reserved bandwidth change request is notified from the traffic monitoring server TMS (within the reserved bandwidth change request unit 207).
[0032]
The label switch router LSRj (j = 1 to 3) is a router having a configuration similar to that of a conventional label switch router. FIG. 4 shows a block configuration of the label switch router LSRj. As shown in the figure, the label switch router LSRj includes a relay unit 401 and traffic information notification units 402 and 403.
[0033]
The relay unit 401 relays a label switch path (LSP) set between the ingress label edge router LER1 and the egress label edge router LER3.
The traffic information notification unit 402 provides traffic information for each link to the traffic monitoring server TMS. The traffic information notification unit 403 provides traffic information for each label switch path to the traffic monitoring server TMS.
[0034]
An overview of processing in the traffic engineering method applied in the traffic engineering system having such a configuration will be described with reference to FIG. That is, the processing in the traffic engineering method according to the present embodiment includes the best effort type traffic trunk dynamic distribution step S101, the bandwidth guaranteed type traffic trunk dynamic distribution step S102, and the trunk unit distribution that summarizes these processes. Step S103 and the step S104 for dynamically changing the label switch path reserved bandwidth are related to each other. As described above, in the traffic engineering method according to the present embodiment, the best effort type and the band guarantee type are considered as traffic transfer classes.
[0035]
The dynamic distribution step S101 of the best effort type traffic trunk is mainly a process of the traffic monitoring server TMS. The traffic state of the label switch network is monitored, and when the label switch network is congested, the best operation is performed to eliminate the congestion. This is a process of distributing an effort type traffic trunk to an optimum label switch path.
[0036]
Bandwidth-guaranteed traffic trunk dynamic distribution step S102 is mainly the processing of the traffic monitoring server TMS, which monitors the traffic state of the label switch network and eliminates congestion when congestion occurs in the bandwidth-guaranteed label switch path. In this process, the bandwidth-guaranteed traffic trunk is distributed to the optimum label switch path.
[0037]
The processing in steps S101 and S102 can be performed independently, but the effect is affected by the combination of the processing timings. For example, if the processing of step S102 is performed at a certain point in time and the bandwidth-guaranteed traffic trunk is allocated, the network traffic distribution changes, and thereafter, the optimal allocation method for the best-effort traffic trunk targeted in step S101 changes. Come.
[0038]
Accordingly, the distribution step S103 for each trunk unit captures the processing of steps S101 and S102 in an integrated manner for the purpose of convergence of the processing of step S101 when the processing of step S102 is considered, and processing timing of step S101 and processing timing of step S102. Is a process for controlling the above in an integrated manner. Specifically, in step S103, priority is given to the bandwidth guarantee type that is more important for the user, and the time interval of the dynamic guarantee step S102 of the bandwidth guarantee type traffic trunk is shorter than the dynamic assignment step S101 of the best effort type traffic trunk. To be controlled.
[0039]
Dynamic change of the label switch path reserved bandwidth Step S104 allocates the guaranteed bandwidth label switch path in Step S102 in response to a request from the traffic monitoring server TMS, and increases the reserved bandwidth of the label switch path as necessary. In addition, once the reserved bandwidth that has been increased is no longer necessary, it is a process of restoring the original bandwidth.
[0040]
As described above, the traffic engineering method applied in the present embodiment is characterized in that the best effort type traffic stably provides high performance while maximizing the performance of the band guaranteed type traffic.
[0041]
Hereinafter, the details of each process of steps S101 to S104 will be described.
First, details of the dynamic distribution step S101 of the best-effort type traffic trunk will be described with reference to the flowchart of FIG. 6 showing the respective processing flows in the traffic monitoring server TMS and the ingress label edge router LER1.
[0042]
First, the traffic monitoring server TMS starts processing, and starts a timer TM1 (not shown) that counts a predetermined time T1 (step S200). The traffic monitoring unit 201 in the traffic monitoring server TMS monitors the traffic on each label switch router LSRj (j = 1 to 3) in units of links (step S201). Here, for the best effort type label switch path LSP, the traffic monitoring unit 201 examines all links through which the LSP passes (step S202). Specifically, the traffic monitoring unit 201 receives, as traffic information for each link from the traffic information notification unit 402 in each label switch router LSRj on the label switch network, the number of received bytes of the input interface of the label switch router LSRj, The input interface link capacity, the output interface transmission byte count, and the output interface link capacity are acquired. Further, the number of discarded packets of the input interface and the number of discarded packets of the output interface may be acquired as traffic information for each link.
[0043]
The traffic information for each link acquired by the traffic monitoring unit 201 from the traffic information notification unit 402 in each label switch router LSRj is passed to the congestion determination unit 203 in the traffic monitoring server TMS. The congestion determination unit 203 searches for a link that is congested in the label switch network from the traffic information for each link delivered from the traffic monitoring unit 201 (step S203). Specifically, the ratio between the link capacity of the interface of each label switch router LSRj and the actual traffic volume (the number of received bytes on the input side and the number of transmitted bytes on the output side) exceeds a threshold value, which is more than a certain number of times. If it continues, the link is considered congested. Basically, it is sufficient to evaluate congestion by evaluating only the input side in each label switch router LSRj, but in the label switch router LSR3 immediately before the exit label edge router LER3, the output side is also evaluated. Need to be targeted. If the number of discarded packets on the input side exceeds the threshold and it continues for a certain number of times, the link may be considered to be congested, or the number of discarded packets on the output side exceeds the threshold, which is a certain number of times. If the above continues, it may be determined that the link is congested.
[0044]
Although these evaluation objects may be arbitrarily combined, what is common here is that it is a link unit.
[0045]
The determination result in the congestion determination unit 203 is passed to the control request unit 205 in the traffic monitoring server TMS together with the traffic information. In response to this, if the determination result in the congestion determination unit 203 indicates that there is a congested link, the control request unit 205 indicates the label edge router LER1 of the LSP (label switch path) corresponding to the link. Next, a traffic control request for distribution of the best effort type traffic including the traffic information is notified (step S204). This traffic control request becomes a trigger for causing the ingress label edge router LER1 to distribute the best effort type traffic trunk. Here, the traffic information included in the traffic control request is traffic information in a link through which all LSPs originating from the corresponding label edge router LER1 pass. Note that when there are a plurality of corresponding LSPs and a plurality of corresponding ingress label edge routers are associated therewith, it is not necessary to notify the traffic information to all the ingress label edge routers all at once. The effect is to suppress flapping that may occur when a plurality of ingress label edge routers simultaneously distribute traffic trunks. For example, a priority may be given to the ingress label edge router to be notified, and traffic information may be notified in order from the ingress label edge router with the highest priority.
[0046]
Thereafter, the traffic monitoring server TMS waits for the timer TM1 to time out (step S204a), and when the time has expired, the TM1 is restarted, and the processes after step S201 are executed. That is, the traffic monitoring server TMS periodically repeats the operation of monitoring the traffic on each label switch router LSRj (j = 1 to 3) in units of links every time T1.
[0047]
On the other hand, in the label edge router LER1, when a traffic control request is notified from the control request unit 205 in the traffic monitoring server TMS, the traffic distribution unit 302 is activated. The traffic distribution unit 302 distributes the best effort type traffic trunk based on the traffic information included in the traffic control request (step S205). In the best effort type traffic trunk assignment step S205, the traffic distribution unit 302 in the label edge router LER1 needs to evaluate LSP (label switch path) candidates to be reassigned to the best effort type traffic trunk. There is. The evaluation procedure is shown below.
[0048]
a. First, if an LSP candidate passes through a congested link, the traffic trunk is not reassigned to that LSP.
[0049]
b. The candidate of the LSP which is not congested is set as “alternative LSP”, and the free capacity of the link is evaluated. Specifically, for each link through which the LSP passes, traffic information is acquired, and the difference between the link capacity of the input (or output) interface and the number of received (or transmitted) bytes of the input (or output) interface is calculated. calculate.
[0050]
c. If the free capacity of each link through which the alternative LSP passes exceeds the traffic volume of the traffic trunk at all locations, the traffic trunk is reassigned to the alternative LSP.
[0051]
Thereafter, the ingress label edge router LER1 continues to receive traffic information from the traffic monitoring server TMS.
The above is the details about the processing of the dynamic distribution step S101 of the best effort type traffic trunk.
[0052]
Next, details of the dynamic allocation step S102 of the bandwidth guarantee type traffic trunk will be described with reference to the flowchart of FIG. 7 showing the respective processing flows in the traffic monitoring server TMS and the ingress label edge router LER1.
[0053]
First, the traffic monitoring server TMS starts processing and starts a timer TM2 (not shown) that counts a predetermined time T2 (step S300). Here, T2 <T1. Then, the traffic monitoring unit 202 in the traffic monitoring server TMS monitors traffic on each label switch router LSRj (j = 1 to 3) in units of LSP (label switch path) (step S301). Here, the traffic monitoring unit 202 checks all the links through which the LSP passes for the bandwidth-guaranteed LSP (step S302). Specifically, the traffic monitoring unit 202 uses the LSP identification information, the number of LSP transfer bytes, and the reserved bandwidth of the LSP as traffic information from the traffic information notification unit 403 in each label switch router LSRj on the label switch network. And identification information of the interface through which the LSP passes.
[0054]
The traffic information for each LSP acquired by the traffic monitoring unit 202 from each label switch router LSRj is passed to the congestion determination unit 204 in the traffic monitoring server TMS. The congestion determination unit 204 searches for LSPs that are congested in the label switch network from the traffic information for each LSP delivered from the traffic monitoring unit 202 (step S303). Specifically, if the ratio between the reserved bandwidth of the LSP and the actual traffic volume of the LSP (the number of received bytes on the input side and the number of transmitted bytes on the output side) exceeds a threshold value, LSPs are considered congested. Basically, it is sufficient to evaluate congestion by evaluating only the input side in each LSR, but in the label switch router LSR3 immediately before the egress label edge router LER3, the output side is also subject to evaluation. There is a need. Also, if the number of discarded packets on the input side exceeds the threshold and it continues for a certain number of times, the LSP may be considered to be congested, or the number of discarded packets on the output side exceeds the threshold, which is a certain number of times. If this continues, the LSP may be determined to be congested.
[0055]
Although these evaluation targets may be arbitrarily combined, what is common here is that they are in LSP (label switch path) units.
[0056]
The determination result in the congestion determination unit 204 is passed to the control request unit 205 in the traffic monitoring server TMS together with the traffic information. In response to this, when the result of determination by the congestion determination unit 204 indicates that there is a congested LSP, the control request unit 205 includes a bandwidth guarantee that includes traffic information in the label edge router LER1 of the LSP. A traffic control request for distribution of type traffic is notified (step S304). This traffic control request is a trigger for causing the ingress label edge router LER1 to distribute a bandwidth guaranteed traffic trunk. Here, the traffic information included in the control information request is traffic information in all LSPs originating from the corresponding label edge router LER1, and the congested LSPs determined by the congestion determination unit 204 can be identified. Information is also included.
[0057]
Thereafter, the traffic monitoring server TMS waits for the timer TM2 to time out (step S304a), and restarts the TM2 when the time has expired, and executes the processing from step S301 onward. In other words, the traffic monitoring server TMS performs an operation for monitoring the traffic on each label switch router LSRj (j = 1 to 3) in units of LSPs every time T2, and in more detail, is shorter than the monitoring operation in units of links. Repeat periodically at periodic intervals.
[0058]
On the other hand, in the label edge router LER1, when a traffic control request is notified from the control request unit 205 in the traffic monitoring server TMS, the traffic distribution unit 302 is activated. The traffic distribution unit 302 searches for alternative LSP candidates based on the traffic information included in the traffic control request, and determines whether there is an alternative LSP candidate (step S305). Here, the alternative LSP candidate matches the destination IP address defined in the LSP that is assigned to the egress label edge router LER3 defined in the traffic trunk, and the same type of guaranteed bandwidth type. An LSP to which a traffic trunk is assigned.
[0059]
If there is an alternative LSP candidate, the traffic distribution unit 302 proceeds to step S306. In contrast, if there is no alternative LSP candidate, the traffic distribution unit 302 cannot distribute the traffic trunk of the congested LSP. In this case, the alert notification unit 304 is activated via the congestion determination unit 303, and “alert” is notified from the alert notification unit 304 to the traffic monitoring server TMS (step S308). This “alert” includes identification information of the congested LSP.
[0060]
In step S306, that is, in step S306 that is executed when there is an alternative LSP candidate, the traffic distribution unit 302 reserves even if a traffic trunk is allocated to the alternative LSP to the alternative LSP candidate. It is determined whether there is room in the bandwidth. Specifically, it is determined whether or not the sum of the current traffic volume flowing on the alternative LSP and the traffic volume of the traffic trunk to be distributed is smaller than the reserved bandwidth of the alternative LSP.
[0061]
If there is room in the reserved bandwidth, the traffic distribution unit 302 distributes the traffic trunk of the LSP that is congested with the alternative LSP (step S307). On the other hand, if there is not enough reserved bandwidth, the traffic distribution unit 302 cannot distribute the corresponding traffic trunk, so the alert notification unit 304 notifies the traffic monitoring server TMS of “alert” via the congestion determination unit 303. (Step S308). This “alert” includes the identification information of the congested LSP.
[0062]
Thereafter, the label edge router LER1 continues to receive traffic information from the traffic monitoring server TMS.
The above is the details of the processing of the dynamic distribution step S102 for the best effort type traffic trunk.
[0063]
Next, the details of the step S104 for dynamically changing the reserved bandwidth of the label switch path will be described with reference to the flowchart of FIG. 8 showing the respective processing flows in the traffic monitoring server TMS and the ingress label edge router LER1.
[0064]
First, the “alert” notified from the alert notification unit 304 in the entrance label edge router LER1 to the traffic monitoring server TMS is received by the reserved bandwidth calculation unit 206 in the traffic monitoring server TMS (step S401). This “alert” includes the identification information of the congested LSP as described above.
[0065]
When “alert” is notified from the label edge router LER1, the reserved bandwidth calculation unit 206 acquires link information and LSP information from each label switch router LSRj via the traffic monitoring unit 202 (step S402). Then, the reserved bandwidth calculation unit 206 determines whether or not the reserved bandwidth of the congested LSP can be increased by referring to the acquired information (step S403). Specifically, the free bandwidth is examined for all the links through which the LSP included in the “alert” passes, and the minimum value is obtained. If the value is larger than a certain reference amount compared to the actual traffic amount of the congested LSP, it is determined that the reserved bandwidth of the congested LSP can be increased to the certain reference amount. In this case, reserved bandwidth change information (to be described later) is passed from the reserved bandwidth calculation unit 206 to the reserved bandwidth change request unit 207, and the reserved bandwidth change request unit 207 is activated. On the other hand, if the free bandwidth is not equal to or greater than the predetermined reference amount, nothing is done and the process returns to step S301 in FIG.
[0066]
When the reserved bandwidth change request unit 207 is activated by the reserved bandwidth calculator 206, it notifies the ingress label edge router LER1 of the reserved bandwidth change information of the LSP (step S404). This reserved bandwidth change information includes a set of identification information of an LSP whose reserved bandwidth is to be changed and the changed reserved bandwidth calculated by the reserved bandwidth calculator 206 in step S403. Here, the reserved bandwidth change request unit 207 in the traffic monitoring server TMS, with respect to the LSP whose reservation bandwidth indicated by the reserved bandwidth change information is to be changed, the original reserved bandwidth of the LSP is the bandwidth of the LSP. It shall be remembered until it is restored.
[0067]
The reserved band change information of the LSP notified to the ingress label edge router LER1 from the reserved band change request unit 207 in the traffic monitoring server TMS is received by the reserved band change unit 305 in the label edge router LER1. Then, the reserved bandwidth changing unit 305 changes (increases) the reserved bandwidth based on the reserved bandwidth change information of the LSP received from the traffic monitoring server TMS (within the reserved bandwidth change request unit 207) (step S405).
[0068]
On the other hand, the traffic monitoring unit 202 in the traffic monitoring server TMS periodically continues to monitor the traffic of each label switch router LSRj (step S406). Then, the congestion judgment unit 204 in the traffic monitoring server TMS has the actual traffic amount for the LSP notified to the label edge router LER1 from the reserved bandwidth change request unit 207 in the previous step S404 (that is, the LSP having an increased reserved bandwidth). It is determined whether or not a predetermined reference amount has been exceeded (step S407). Specifically, if the ratio between the reserved bandwidth of the LSP and the actual traffic volume of the LSP (the number of received bytes on the input side, the number of transmitted bytes on the output side) falls below the threshold, For LSP, it is considered that the actual traffic volume has fallen below a predetermined reference volume. In this case, the reserved bandwidth change request unit 207 executes step S408. Basically, it is sufficient to evaluate congestion by evaluating only the input side in each label switch router LSRj, but in the label switch router LSR3 immediately before the exit label edge router LER3, the output side is also evaluated. Need to be targeted. In addition, if the number of discarded packets on the input side falls below the threshold and continues for a certain number of times, the LSP may consider that the actual traffic volume has fallen below a predetermined standard, and the number of discarded packets on the output side falls below the threshold. If this continues for a certain number of times, the LSP may consider that the actual traffic volume has fallen below a predetermined standard.
[0069]
Although these evaluation objects may be combined arbitrarily, what is common here is that they are LSP units.
[0070]
In step S408, the reserved bandwidth change request unit 207 notifies the label edge router LER1 of the reserved bandwidth change information of the LSP. Here, the reserved bandwidth change information notified to the label edge router LER1 is the identification information of the LSP whose reserved bandwidth is to be changed and the original reserved bandwidth stored in the reserved bandwidth change request unit 207. When the reserved bandwidth change request unit 207 notifies the reserved bandwidth change information, the reserved bandwidth change request unit 207 deletes the stored content of the LSP that has received the alert.
[0071]
When step S408 ends, the traffic monitoring server TMS returns to the process of step S301 in FIG. 7 and repeats periodic traffic monitoring.
[0072]
On the other hand, in the label edge router LER1, based on the LSP reserved band change information from the reserved band change request unit 207 in the traffic monitoring server TMS, the reserved band changing unit 305 in the label edge router LER1 reserves the corresponding LSP. The band is changed (decreased) (step S409).
[0073]
By the way, the setting of various time interval parameters in the traffic monitoring server TMS is very related to the practical effect of the traffic engineering method applied in the present embodiment. With respect to this, a case will be described in which the above-described traffic engineering method is applied to, for example, a VoMPLS (Voice over MPLS) service considering bandwidth guarantee.
[0074]
In this example, it is considered that the service provider only needs to distribute the route or change the reserved bandwidth several times during the day. In other words, traffic engineering is provided by setting price plans such as daytime, evening, and late-night early morning.
[0075]
Considering such a practical application, it is assumed that traffic distribution or reservation bandwidth change operates at intervals of, for example, about 30 minutes. In this case, assuming that the change in the traffic volume of the network (here, the Internet) occurs exponentially, the interval at which the traffic monitoring server TMS periodically collects traffic information from each label switch router LSRj is 10 minutes. It turns out that. In the above 30 minutes, which is three times this tenth, the traffic amount with respect to the capacity of the link or the traffic amount with respect to the reserved bandwidth of the label switch path reaches 95%.
[0076]
Hereinafter, specific values of various time interval parameters that can be set in the traffic monitoring server TMS will be described.
[0077]
(1) Bandwidth guaranteed LSP traffic information collection time interval
This value ignores the influence of all control delays including internal processing of communication protocols related to this embodiment, such as RSVP-TE protocol, XMLOVERTELNET protocol, traffic monitoring server TMS, label edge router, and label switch router. The interval can be set as loose as possible. Here, the traffic information collection time interval of the bandwidth guaranteed LSP, that is, the time T2 measured by the timer TM2 is set to 10 minutes.
[0078]
(2) Congestion threshold for bandwidth guaranteed LSP
The threshold value for determining the congestion of the bandwidth-guaranteed LSP is a threshold value for determining what percentage the bandwidth used by the actual traffic carried by the LSP exceeds “reserved”. Here, this value is 95%.
[0079]
(3) Number of times of congestion judgment for bandwidth guaranteed LSP
The number of times of congestion determination of the bandwidth guaranteed LSP is the number of times that the traffic amount collected at the information collection time interval of the bandwidth guaranteed LSP exceeds the value determined by the congestion determination threshold of the bandwidth guaranteed LSP. This value sets whether to activate trunk distribution control. Here, this value is set to 3 times.
[0080]
(4) Best effort LSP information collection time interval
In this embodiment, priority is given to the bandwidth guarantee type traffic, and after switching to dynamic allocation (step S102) of the bandwidth guarantee type traffic trunk by TE control, when the traffic has settled again, the best effort type traffic trunk Switching to dynamic distribution (step S101) is performed. Therefore, the information collection time interval of the best effort type LSP, that is, the time T1 measured by the timer TM1, is set to, for example, three times the information collection time interval of the band guaranteed LSP, that is, 30 minutes. Note that when the information collection timing of the best effort type LSP matches the information collection timing of the bandwidth guaranteed LSP, the information collection of the bandwidth guaranteed LSP may be prioritized.
[0081]
(5) Best effort LSP congestion judgment threshold
The threshold value for determining the congestion of the best effort type LSP is a threshold value for determining “congestion” when the bandwidth used by the actual traffic carried on the link exceeds a certain link capacity. Here, this value is 85%.
[0082]
(6) Number of congestion judgments of best effort LSP
The number of times of congestion determination of the best effort LSP is the number of times the amount of traffic collected at the information collection time interval of the best effort LSP exceeds the value determined by the congestion determination threshold of the best effort LSP. This value sets whether to activate trunk distribution control. Here, this value is set to 3 times, similarly to the number of times of congestion judgment of the bandwidth guaranteed LSP.
[0083]
(7) Information collection time interval for determining bandwidth reduction
This value is set to 15 minutes for the purpose of decreasing at a slightly slower interval than the information collection time interval (10 minutes) for increasing the bandwidth.
[0084]
(8) Bandwidth reduction threshold
The threshold for bandwidth reduction determination is a threshold for determining what percentage the bandwidth used by the actual traffic carried by the LSP is “decreased” for an LSP whose reservation bandwidth has been increased once. . Here, this value is set to 30%.
[0085]
(9) Number of bandwidth reduction judgments
The number of times of bandwidth reduction determination is reserved when the amount of traffic collected at the information collection time interval for determining the bandwidth reduction falls below the value determined by the threshold for bandwidth reduction determination. This is a value for setting whether to start the control to reduce the bandwidth and restore it. Here, this value is set to 3 times.
[0086]
In addition, this invention is not limited to the said embodiment, In the implementation stage, it can change variously in the range which does not deviate from the summary. Further, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some constituent elements are deleted from all the constituent elements shown in the embodiment, at least one of the problems described in the column of the problem to be solved by the invention can be solved, and is described in the column of the effect of the invention. When at least one of the effects is obtained, a configuration in which this configuration requirement is deleted can be extracted as an invention.
[0087]
【The invention's effect】
As described above in detail, according to the present invention, the traffic information of the label switch path is used for determining the congestion of the bandwidth-guaranteed traffic, and the traffic information of the link is used for determining the congestion of the non-bandwidth-guaranteed traffic. Integrated control to allocate bandwidth-guaranteed traffic and non-bandwidth-guaranteed traffic to the optimal label switch path based on congestion judgment results, so bandwidth-guaranteed traffic and non-bandwidth-guaranteed traffic are loaded in an integrated manner Network resources can be used effectively by optimizing the performance of bandwidth-guaranteed traffic and non-bandwidth-guaranteed traffic.
[0088]
In addition, according to the present invention, priority is given to the allocation of bandwidth guaranteed traffic over the allocation of non-bandwidth guaranteed traffic, thereby maximizing the performance of bandwidth guaranteed traffic that is more important to the user, while also guaranteeing the non-bandwidth guaranteed traffic. High performance can be stably achieved.
[0089]
Further, according to the present invention, even when congestion cannot be solved only by traffic distribution, the congestion can be eliminated by adjusting the reserved bandwidth, so that network resources can be used more effectively.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a schematic configuration of a traffic engineering system according to an embodiment of the present invention.
FIG. 2 is a block diagram showing a configuration of a traffic monitoring server TMS in FIG.
FIG. 3 is a block diagram showing a configuration of an entrance label edge router LER1 in FIG. 1;
4 is a block diagram showing a configuration of a label switch router LSRj (j = 1 to 3) in FIG. 1. FIG.
FIG. 5 is a view for explaining an overview of processing in the embodiment;
FIG. 6 is a flowchart for explaining details of a best effort type traffic trunk dynamic distribution step S101 in FIG. 5;
FIG. 7 is a flowchart for explaining details of a bandwidth guarantee type traffic trunk dynamic distribution step S102 in FIG. 5;
FIG. 8 is a flowchart for explaining details of a step S104 for dynamically changing the reserved bandwidth of the label switch path in FIG. 5;
[Explanation of symbols]
TMS ... Traffic monitoring server (traffic monitoring server device)
LER1 ... label edge router (ingress label edge router, first label edge router)
LER3 ... label edge router (exit label edge router, second label edge router)
LSR1, LSR2, LSR3, LSRj ... Label switch router
LSP1, LSP2 ... best effort label switch path (non-bandwidth guaranteed label switch path)
LSP3, LSP4 ... Band Guaranteed Label Switch Path
201: Traffic monitoring unit (first traffic monitoring means)
202 ... Traffic monitoring unit (second traffic monitoring means)
203 ... Congestion determination unit (first congestion determination means)
204: Congestion determination unit (second congestion determination means)
205: Control request section
206: Reserved bandwidth calculator
207 ... Reserved bandwidth change request section
301 ... LSP setting section
302 ... Traffic distribution part
303 ... Congestion determination unit (third congestion determination means)
304: Alert notification unit
305 ... Reserved bandwidth changing unit
401: Relay unit
402: Traffic information notification unit

Claims (12)

A plurality of band guarantee type labels including a label switch path that forms a detour path between a first label edge router serving as a starting point of one core network constituting a label switch network and a second label edge router serving as an end point A traffic engineering in which a plurality of non-bandwidth guaranteed type label switch paths including a switch path and a label switch path forming a detour path are set, and at least one of the set label switch paths is relayed by at least one label switch router A traffic monitoring server device applied to the system, wherein the traffic monitoring server device obtains traffic information per link from the at least one label switch router;
Second traffic monitoring means for acquiring traffic information and reserved bandwidth information for each label switch path from the at least one label switch router;
First congestion determination means for determining the congestion status of the non-bandwidth guaranteed type label switch path based on the traffic information acquired by the first traffic monitoring means;
Second congestion determination means for determining the congestion status of the bandwidth guaranteed label switch path based on the traffic information and reserved bandwidth information acquired by the second traffic monitoring means;
A traffic control request for allocating non-bandwidth guaranteed traffic or bandwidth guaranteed traffic to an optimum label switch path by the first label edge router based on a congestion status determination result by the first or second congestion determination means. A traffic monitoring server device comprising control request means for notifying the first label edge router. The control requesting unit distributes the bandwidth guarantee type traffic based on the congestion state determination result by the second congestion determination unit from the distribution of the non-bandwidth guarantee type traffic based on the congestion state determination result by the first congestion determination unit. 2. The traffic monitoring server device according to claim 1, wherein priority is given. The first traffic monitoring means executes the traffic information acquisition of the link unit at a first time interval,
2. The second traffic monitoring means executes the traffic information acquisition and reserved bandwidth information acquisition for each label switch path in a second time interval shorter than the first time interval. Item 3. The traffic monitoring server device according to Item 2. If the congestion of the bandwidth-guaranteed label switch path is not eliminated even by the traffic distribution by the first label edge router based on the control of the control request means, the reserved bandwidth notified from the first label edge router Reservation bandwidth calculation means for receiving the change value request and calculating the value of the reserved bandwidth that can be increased for the bandwidth-guaranteed label switch path in which the congestion is not resolved,
2. The reserved bandwidth change requesting means for requesting the first label edge router to change to a value of an increase in reserved bandwidth calculated by the reserved bandwidth calculating means. Traffic monitoring server device. The second congestion determination means determines the congestion status of the corresponding label switch path even after the reserved bandwidth change request from the reserved bandwidth change request means to the first label edge router,
The reserved bandwidth change requesting means is based on a reserved bandwidth of the corresponding label switch path based on a congestion status determination result by the second congestion determining means after a reserved bandwidth change request to the first label edge router. 5. The traffic monitoring server device according to claim 4, wherein a change in reserved bandwidth for returning is requested to the first label edge router. A first label edge router serving as a starting point of one core network constituting the label switch network;
A second label edge router serving as an end point of the core network;
A plurality of non-bandwidth guarantees including a plurality of bandwidth-guaranteed label switch paths including a label switch path that forms a detour path and a label switch path that forms a detour path set between the first and second label edge routers At least one label switch router relaying at least one of the label switch paths of the type;
A traffic monitoring server that centrally manages at least the traffic information of the entire core network and performs integrated traffic control and resource control;
The traffic monitoring server device includes first traffic monitoring means for obtaining traffic information in units of links from the at least one label switch router, and traffic information and reserved bandwidth information in units of label switches from the at least one label switch router. Second traffic monitoring means for acquiring the first traffic determination means, first congestion determination means for determining the congestion status of the non-bandwidth guaranteed type label switch path based on the traffic information acquired by the first traffic monitoring means, and the first Congestion by the second congestion determination means for determining the congestion status of the bandwidth-guaranteed label switch path based on the traffic information and reserved bandwidth information acquired by the traffic monitoring means of 2 and the congestion by the first or second congestion determination means Non-bandwidth guaranteed traffic or bandwidth protection based on the status judgment result The traffic control request to let the distribution type traffic to the optimum label switched path by the first label edge router and a control request means for notifying the first label edge router,
The first label edge router includes label switch path setting means for setting a label switch path between the first label edge router and the second label edge router, and the control request of the traffic monitoring server device. A traffic engineering system, comprising: a non-bandwidth-guaranteed traffic or a traffic distribution unit that distributes the bandwidth-guaranteed traffic to an optimum label switch path in response to a traffic control request from the means. The first label edge router has third congestion determination means for determining whether or not congestion of a bandwidth guaranteed label switch path has been eliminated as a result of distributing the bandwidth guaranteed traffic by the traffic distributing means; An alert notification means for notifying the traffic monitoring server apparatus of an alert indicating a request for a change value of a reserved bandwidth when the third congestion determination means determines that the congestion is not eliminated; and from the traffic monitoring server apparatus A reserved bandwidth changing means for changing the reserved bandwidth of the bandwidth guarantee type label switch path corresponding to the reserved bandwidth change request of
The traffic monitoring server device calculates a reserved bandwidth calculating means for calculating a value of a reserved bandwidth that can be increased in a bandwidth-guaranteed label switch path in which congestion is not eliminated in response to an alert from the alert notification means of the first label edge router. And reserved bandwidth change requesting means for requesting the first label edge router to change to the value of the increase in reserved bandwidth calculated by the reserved bandwidth calculating means. 6. The traffic engineering system according to 6. 7. The traffic engineering system according to claim 6, wherein the traffic monitoring server device is provided in any of the first label edge router, the second label edge router, or the label switch router. A plurality of band guarantee type labels including a label switch path that forms a detour path between a first label edge router serving as a starting point of one core network constituting a label switch network and a second label edge router serving as an end point A traffic engineering in which a plurality of non-bandwidth guaranteed type label switch paths including a switch path and a label switch path forming a detour path are set, and at least one of the set label switch paths is relayed by at least one label switch router A traffic engineering method applied to a system,
Obtaining traffic information per link by the traffic monitoring server from the at least one label switch router at a first time interval;
Obtaining traffic information and reserved bandwidth information for each label switch path from the at least one label switch router by the traffic monitoring server at a second time interval;
Determining the congestion status of the non-bandwidth-guaranteed label switch path at the traffic monitoring server based on the link unit traffic information;
Determining the congestion status of a bandwidth-guaranteed label switch path based on the traffic information and reserved bandwidth information in units of label switch paths at the traffic monitoring server;
A first traffic control request for allocating non-bandwidth guaranteed traffic to an optimum label switch path based on a determination result of a congestion state of the non-bandwidth guaranteed label switch path is sent from the traffic monitoring server to the first label edge router. The step of notifying
The traffic monitoring server notifies the first label edge router of a second traffic control request for allocating the bandwidth guaranteed traffic to the optimum label switch path based on the determination result of the congestion status of the bandwidth guaranteed label switch path. And steps to
Allocating non-bandwidth guaranteed traffic to the optimum label switch path by the first label edge router according to the first traffic control request, and optimizing bandwidth guaranteed traffic according to the second traffic control request And a step of allocating to a different label switch path by the first label edge router. Determining in the first label edge router whether or not congestion of a bandwidth guaranteed label switch path has been resolved as a result of performing the allocation for the bandwidth guaranteed traffic in response to the second traffic control request;
An alert indicating a request for changing the reserved bandwidth from the first label edge router to the traffic monitoring server when congestion of the bandwidth guaranteed label switch path is not resolved even after the bandwidth guaranteed traffic is allocated. A step of notifying
In response to the alert from the first label edge router, the traffic monitoring server calculates a value of a reserved bandwidth that can be increased in a bandwidth-guaranteed label switch path in which congestion is not eliminated;
Requesting the first label edge router from the traffic monitoring server to change to a calculated increaseable reserved bandwidth value;
10. The method according to claim 9, further comprising a step of changing a reserved bandwidth of a bandwidth guarantee type label switch path corresponding to a reserved bandwidth change request from the traffic monitoring server at the first label edge router. The described traffic engineering method. A plurality of band guarantee type labels including a label switch path that forms a detour path between a first label edge router serving as a starting point of one core network constituting a label switch network and a second label edge router serving as an end point A traffic engineering in which a plurality of non-bandwidth guaranteed type label switch paths including a switch path and a label switch path forming a detour path are set, and at least one of the set label switch paths is relayed by at least one label switch router A traffic monitoring program applied to the system,
On the computer,
Obtaining per-link traffic information from the at least one label switch router at a first time interval;
Obtaining traffic information and reserved bandwidth information for each label switch path from the at least one label switch router at a second time interval;
Determining the congestion status of the non-bandwidth guaranteed label switch path based on the traffic information per link;
Determining the congestion status of a bandwidth-guaranteed label switch path based on the traffic information and reserved bandwidth information in units of label switch paths;
The first traffic control request for distributing the non-bandwidth guaranteed traffic to the optimum label switch path by the first label edge router based on the determination result of the congestion state of the non-bandwidth guaranteed label switch path is the first traffic control request. Informing the label edge router of
Based on the result of determination of the congestion status of the bandwidth-guaranteed label switch path, a second traffic control request for distributing bandwidth-guaranteed traffic to an optimal label switch path by the first label edge router is assigned to the first label. A traffic monitoring program for executing the step of notifying the edge router. In the computer,
The reserved bandwidth notified from the first label edge router when the congestion of the bandwidth-guaranteed label switch path is not eliminated even by the traffic distribution by the first label edge router based on the second traffic control request Receiving a request for a change value, and calculating a value of a reserved bandwidth that can be increased in a bandwidth-guaranteed label switch path in which the congestion is not resolved;
12. The traffic monitoring program according to claim 11, further comprising the step of: requesting the first label edge router to change to the calculated increaseable reserved bandwidth value.

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