JP2002344492A - Method and system for switching path by priority order - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make effective use of a backup path, prevent the destruction of a packet, and improve a traffic service. SOLUTION: In a network having an MPLS function where in ordinary path and a backup path between HOST devices 300 and 301 are set in advance by means of MPLS accommodating devices 200, 201, and 202, a network management system 100 is installed, which fetches and analyzes the traffic data of each MPLS accommodating device and controls the MPLS accommodating devices, so that a packet on a traffic with low priority on the ordinary path may be switched to a backup path in a congested state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-protocol label switching system.
ng: Hereinafter, "MPLS". The present invention relates to a path switching method for switching a path between devices having functions (hereinafter, referred to as “MPLS-compatible devices”) using a network management system.
The present invention relates to a priority-based path switching method and method for performing traffic analysis of an S-compatible device and switching paths according to the priority of traffic.

[0002]

2. Description of the Related Art In traffic such as the WEB (world wide web) which is most frequently used on the Internet, a traffic service which does not guarantee a predetermined or higher communication quality for low priority traffic is used. In other words, the best effort type (best eff type) that does not guarantee the value of the communication throughput (throughput) or the like.
ort type) traffic is applied. In a service for such traffic, when burstiness is continuous, or when congestion or congestion occurs, packet discarding may occur for traffic with a low priority. Also,
There has also been proposed a communication method for transferring low-priority traffic packets to a different new path during congestion or the like (Japanese Patent Laid-Open No. 2000-332777).

[0003]

In a network sharing the facilities of nodes and links, a communication method according to a service class such as a best effort service is used, but in such a network, traffic increases. If the effective end-to-end transmission speed decreases with this, traffic is discarded, and in systems where discarded packets cannot be rescued, the reliability and reliability of high-priority traffic using the same path are There is a problem that a situation where the communication quality is not guaranteed may occur.

[0004] Therefore, a backup path is reserved and set in advance for the path (normal path) used at the time of normal operation set on the network. In the case of congestion, congestion, or a failure that may cause discard of high-priority traffic, etc., it is conceivable to use a method of performing path switching for all traffic packets of the normal path. Is not used even in the case of discarding a packet by a best-effort service or the like by a normal path, and thus there is a problem in effective use of network resources. Also, the method of transferring low-priority traffic to a different new path at the time of congestion or the like requires a change in network routing policy, complicates the routing algorithm, and makes it difficult to realize rapid path switching. Become.

(Purpose) An object of the present invention is to provide a path switching method and method for each priority according to the priority of a traffic which can effectively use the network resources of a network which reserves a backup path for a normal path. Is to provide.

Another object of the present invention is to provide a priority-based path switching method and system capable of preventing discarding of packets even when congestion of best-effort type traffic on a network and improving traffic service. Is to do.

[0007]

SUMMARY OF THE INVENTION The present invention provides a method and system for priority-based path switching in which traffic analysis of an MPLS-compatible device is performed using a network management system and path switching of the MPLS-compatible device is performed using the analysis result. Is provided. That is,

A priority-based path switching method according to the present invention is a priority-based path switching method by a network management system for switching a multiprotocol label switching path of a packet in accordance with a traffic priority. Sets a normal path and a backup path between the host devices by the MPLS-compatible device,
Performs traffic analysis of the PLS-compatible device, notifies the MPLS-compatible device of the traffic analysis result, and the MPLS-compatible device includes a label mapping table that holds relation information between labels and priorities, and based on the traffic analysis result, Referring to the label mapping table, relabel the packet according to the priority of the traffic,
It is characterized in that packets of low-priority traffic are switched from the normal path to the backup path. The network management system, as a traffic analysis result of the MPLS-compatible device, based on the traffic data acquired from the MPLS-compatible device, the number of discarded packets of the normal path exceeds a predetermined number, and the number of discarded packets of the backup path is less than a predetermined number Is notified to the MPLS-compatible device, and the MPLS-compatible device
It is characterized in that a label of a packet having a low traffic priority is re-labeled.

The priority-based path switching method according to the present invention is a priority-based path switching method by a network management system for switching a multiprotocol label switching path of a packet in accordance with a traffic priority. The system includes a path management unit that sets a normal path and a backup path between the host devices by the MPLS-compatible device, performs a traffic analysis, and stores the traffic analysis result in M.
A traffic data management unit for notifying the PLS-compatible device, the MPLS-compatible device includes a label / mapping table management unit for managing a label / mapping table holding information relating to labels and priorities, and And a label swapping processing unit for changing the label of the packet so as to switch the packet of the low priority traffic from the normal path to the backup path with reference to the label mapping table. The network management system includes an MP
When the number of discarded packets on the normal path exceeds a predetermined number based on the traffic data acquired from the MPLS-compatible device and the number of packets discarded on the backup path is equal to or less than a predetermined number as a traffic analysis result of the LS-compatible device, the MPLS-compatible device , And the MPLS-compatible apparatus changes the label of a packet with a low traffic priority.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (Description of Configuration) One embodiment of a method and system for switching paths by priority according to the present invention will be described below. FIG. 1 is a diagram illustrating an example of a system configuration according to the present embodiment. In the example shown in the figure, the network management system (Ne
twork Management System: Hereinafter, also referred to as “NMS”. ) 100, a plurality of MPLS-compatible devices 200, 201, 202 managed by the NMS 100, and each MPL.
Trunk lines 501, 502, and 503 connecting the S-compatible devices 200, 201, and 202;
And HOST device 300, MPLS compatible device 201 and HO
Each subscriber line 5 connecting to the ST device 301
04 and 505.

[0011] The HOST devices 300 and 301 are accommodated in the MPLS-compatible device via the subscriber lines 504 and 505, and are connected to the MPLS-compatible device and the relay lines 501 and 50 thereof.
A packet communication is performed by setting a path via the communication paths 2 and 503.

For example, a HOST device 300 accommodated in an MPLS-compatible device 200 via a subscriber line 504,
Between the MPLS-compatible device 201 and the HOST device 301 accommodated through the subscriber line 505, the MPLS-compatible device 200, the trunk line 501, and the MPLS-compatible device 20
Label Switched Path (Label Switched
Path: Hereinafter, also referred to as “LSP”. ) Is set.
The HOST device 300 and the HO
MPLS-compatible device 200, trunk line 502, MPLS-compatible device 202, trunk line 50
Path LS via the MPLS3 and MPLS-compatible device 201
P is set.

Further, the network management system NMS and the MPLS-compatible device analyze the traffic of the MPLS-compatible device in the NMS, and based on the analysis result,
By performing path switching for each traffic priority in the PLS-compatible device, there is a configuration in which switching to a backup path is performed in units of packets for traffic having a low priority when line congestion occurs.

For example, as a result of collecting traffic data in the MPLS-compatible device 200 or the MPLS-compatible device 201 and acquiring and analyzing the traffic data in the network management system NMS, the number of discarded packets in a certain period T [h] is reduced. Allowable amount X [packet
s], the label of a traffic packet having a low priority (for example, a priority lower than the best effort) is changed, and switching to the protection path LSP set as a protection is performed. MP
A request is made to the LS-compatible device 200 or the MPLS-compatible device 201, and the MPLS-compatible device 200 or the MPL
The S-compatible device 201 switches a packet that meets the above condition to the backup path LSP.

FIG. 2 shows a network management system NMS.
FIG. 3 is a diagram showing the configuration of FIG. Network management system NM
S100 includes a traffic data acquisition processing unit 110, a path management unit 120, and a communication processing unit 130.

The traffic data acquisition processing section 110 has a function of managing traffic data. The traffic data acquisition processing unit 110 includes a timer, and periodically acquires traffic data. The traffic data acquisition processing unit 112 includes a timer, and the traffic data analysis processing unit analyzes the traffic data acquired by the traffic data acquisition processing unit 112. 111.

The path management unit 120 has a function of setting, changing, and managing paths. The path management unit 120 stores a service class (Class of Service: hereinafter, corresponding to the label).
It is called “CoS”. ), A path status management unit 121 that holds information indicating a mapping relationship with the
A request for switching the label to the LS-compatible device, that is, a path switching request, setting a path such as a normal path and a backup path, and requesting the traffic data obtaining processor 112 to obtain traffic data of the MPLS-compatible device in relation to the set path. And a path setting / change processing unit 122 that instructs the path state management unit 121 to start path state management and the like.

The communication processing unit 130 is a communication for instructing the traffic data acquisition processing unit 112 to acquire traffic data, a communication for requesting a path setting / change from the path setting / change processing unit 122, and a management target. It has a function of communicating with an MPLS-compatible device registered as.

FIG. 3 is a diagram showing the configuration of an MPLS compatible device. The MPLS compatible device includes a label swapping processing unit 210 and a label mapping table management unit 22.
0, the traffic data processing unit 230, and the communication processing unit 2
40.

The label swapping section 210 has a function of changing the label of a received packet. The label mapping table management unit 220 includes a label mapping table indicating the correspondence between labels and CoS, and has a function of managing the label mapping table. The traffic data processing unit 230
Regarding the packet input or passed to the PLS compatible device,
It has a function to collect and accumulate traffic data including discarded packets for each CoS. The communication processing unit 240 performs communication with the network management system NMS, performs communication for transmitting the requested traffic data to the traffic data acquisition processing unit 112, and sets / changes a path to the path setting / change processing unit 122. Has a function of performing communication for making a request.

In the above configuration, as described above, the normal route is defined as the HOST device 300-subscriber line 504-MP.
LS-compatible device 200-relay line 501-MPLS-compatible device 201-subscriber line 505-HOST device 301, and MPLS-compatible device 200-relay line 501-MPL
As a backup path for the S-compatible device 201, the trunk line 5
When it is assumed that 02-MPLS corresponding device 202-relay line 503 has been set, the processing operation of each unit is as follows.

The path setting processing unit 122 of the network management system 100 includes the MPLS compatible devices 200, 201,
The label / mapping table of the label / mapping table management unit 220 of 202 is updated, and a normal path is set to the MPLS-compatible devices 200 and 201, and a backup path is set to the MPLS-compatible devices 200, 201 and 202.

Each MPLS-compatible device performs label replacement in the label swapping processing section 210 in accordance with the set label mapping table, and calculates the number of packets such as discarded packets from the packets input or passed for each CoS in the traffic data processing section. Store at 230.

The traffic data acquisition processing unit 112 of the network management system 100 transmits, via the communication processing unit 130, the MPLS in which the normal path and the backup path are set.
The traffic data stored in the corresponding device is acquired at regular intervals, and the acquired data is transmitted to the traffic data analysis processing unit 1.
Hand over to 11.

In the traffic data analysis processing unit 111,
During the period T [h], it is checked whether or not there is discard of a packet exceeding the allowable packet number X [packets]. When the number of discarded packets exceeding the allowable amount is detected, the information is transmitted to the path management unit 120. Is notified to the path state management unit 121.

The path state management unit 121 checks the state of the backup path, and if the state of the backup path is normal and the number of discarded packets in the backup path does not exceed the allowable amount, low priority traffic such as the best traffic. It instructs the bus setting / change processing unit 130 to execute switching to the backup path for traffic having a priority lower than the effort.

The bus setting / change processing unit 130 is an MPLS
A request to change the label mapping table is sent to the corresponding device 200 and the MPLS-compatible device 201 so as to change the label replacement, and the switching of the priority traffic to the backup path is performed.

With the processing configuration and function of each unit described above, M
A path switching for each priority is realized by traffic analysis for a PLS compatible device.

(Explanation of Operation) FIG. 4 is a diagram showing a sequence of the entire operation of the present embodiment. The operation of the present embodiment will be described in detail below based on the operation sequence shown in FIG.

1. Network management system NMS10
0 sets the path from the path setting / change processing unit 122 to the MPLS-compatible device, and sets the path state management, the monitoring setting, and the traffic data to the path state management unit 121 and the traffic data acquisition processing unit 112, respectively. Set the start of acquisition.

2. In the traffic data acquisition processing unit 112, a timer is started according to the setting of the start of traffic data acquisition, and a traffic data acquisition request is issued to the MPLS compatible device at a fixed period t [h] to acquire data. Repeat. The obtained traffic data is passed to the traffic data analysis processing unit 111.

3. The traffic data analysis processing unit 111 checks whether or not there is discarding of a packet exceeding the allowable number of packets X [packets] during the cycle T [h] based on each passed traffic data. I do.

4. When the traffic data analysis processing section 111 detects the number of discarded packets exceeding the allowable value, it notifies the path state management section 121 to confirm the bus state.

5. The path status management unit 121 checks the status of the backup path when notified of the confirmation of the bus status. If the status is normal and the number of discarded packets in the backup path does not exceed the allowable amount, , Path setting / change processing unit 122
, A path switching trigger notification is sent to the effect that switching of the path has been triggered.

6. The path setting / change processing unit 122 instructs the MPLS-compatible apparatus to perform label replacement for low-priority traffic, for example, traffic having a level equal to or lower than best effort, based on the notification of a path switching trigger. Request to change the label mapping table.

7. The MPLS-compatible device updates the label mapping table of the label mapping table management unit 220, and performs label replacement of the received packet for the low-priority traffic in the label swapping processing unit 210. Switch to the backup path.

When the path management unit 120 deletes the above-described path setting, the path setting of the MPLS-compatible device is released, the bus state management unit 121 and the traffic data acquisition processing unit 112 stop processing, and the traffic data The management unit 110 stops collecting traffic data, and stops the operation of the timer.

Next, the traffic data analysis processing unit 111
With regard to the method of analyzing traffic data in, an analysis process for determining the number of discarded packets exceeding an allowable value will be described. .., T are continuous periods of the constant period t.
, and the number of discarded packets detected from the traffic data acquired in each cycle is x1, x2,.
xm,..., a predetermined number of cycles n is set, and a reference cycle T for detecting the number of discarded packets exceeding the allowable number of packets.
[H], period T [h] = constant period t [h] × n
Set [Number of cycles].

The traffic data analysis processing unit 111 calculates m
In the tm-th cycle, the sum Xm of the number of discarded packets from the (m−n + 1) th traffic data to the m-th traffic data is calculated as the number of discarded packets in the period of the cycle T [h], and the sum Xm Is compared with the permissible value X regarding the number of discarded packets, and when the sum Xm exceeds the permissible value X regarding the number of discarded packets, the path state management unit 1
A bus status confirmation signal to be notified to 21 is output.

FIG. 5 is a diagram showing an example of the detection processing flow of the number of discarded packets exceeding the allowable value by the analysis method. According to the bus setting (s1) of the bus management unit 120, the traffic data management unit 110 starts a timer (ss).
2), the traffic data acquisition processing unit 112 outputs the traffic data xm of a fixed period t defined by the timer.
Is collected (s3). Traffic data analysis processing unit 11
1 is a period T [h] for each acquired traffic data xm
The operation (s4) of calculating the sum Xm and comparing it with the allowable value X is repeated while the timer is operating (s5), and when the sum Xm exceeds the allowable value X regarding the number of discarded packets, the path state management unit 121 The bus state is checked (S6). When the bus management unit 120 deletes the path setting, the operation of the timer stops, and the above processing stops.

[0041]

According to the present invention, in a network having an MPLS function in which a backup path is reserved for a normal path, a network management system is used to obtain traffic data of an MPLS-compatible device constituting the path. By analyzing and controlling the MPLS-compatible device to switch the packets of the low priority traffic of the normal path to the backup path at the time of congestion or the like, the backup path that is not normally used can be used. Can be used effectively. In addition, by utilizing a backup path by switching packet labels, high-priority packets can be smoothly transferred on a normal path, and discarded packets can be rescued, improving communication quality and convenience for many users and carriers. Can be realized.

In particular, in the best effort type traffic, packet discarding may occur when the network is congested or congested. However, when the burstiness is continuous, when the congestion or congestion is expected. In this case, since the backup path can be used effectively and packet discarding can be prevented, the traffic service on the network can be further improved.

In the network management system, M
Periodically obtains traffic data from the PLS-compatible device, analyzes the number of discarded packets from a predetermined number of obtained traffic data and the allowable value thereof, checks the status of the working path and the protection path, and changes the state of the normal path to the protection path. The switching to the backup path is determined and controlled, and a communication failure after switching to the backup path can be prevented beforehand, and the control is simplified and the switching can be performed quickly.

[Brief description of the drawings]

FIG. 1 is a diagram showing a system configuration according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a configuration example of a management management system.

FIG. 3 is a diagram illustrating a configuration example of an MPLS-compatible device.

FIG. 4 is a flowchart showing an operation sequence according to the present embodiment.

FIG. 5 is a flowchart showing a process of a traffic data analysis processing unit.

[Explanation of symbols]

 Reference Signs List 100 Network management system 200, 201, 202 MPLS compatible device 300, 301 HOST device 501, 502, 503 Trunk line 504, 505 Subscriber line

Claims (6)

[Claims] 1. A priority-based path switching method by a network management system for switching a multi-protocol label switching path of a packet according to the priority of traffic, the network management system comprising: The normal path and the backup path are set, the traffic analysis of the MPLS-compatible device is performed, the result of the traffic analysis is notified to the MPLS-compatible device, and the MPLS-compatible device stores the label information holding the relation information between the label and the priority. Comprising a mapping table, referring to the label mapping table based on the traffic analysis result, re-labeling the packet according to the priority of the traffic, and switching the packet of the low-priority traffic from the normal path to the backup path. Priority-based path disconnection characterized by Method. 2. The network management system according to claim 1, wherein
When the number of discarded packets on the normal path exceeds a predetermined number based on the traffic data acquired from the MPLS-compatible device and the number of packets discarded on the backup path is equal to or less than a predetermined number as a traffic analysis result of the LS-compatible device, the MPLS-compatible device 2. The priority-based path switching method according to claim 1, wherein the MPLS-compatible device relabels a packet having a low traffic priority. 3. The priority-based path switching method according to claim 1, wherein the MPLS-compatible device acquires traffic data of a packet and notifies the network management system of the packet data. 4. A priority-based path switching method by a network management system for switching a multi-protocol label switching path of a packet according to the priority of traffic, wherein the network management system is a host device by an MPLS-compatible device. A path management unit that sets a normal path and a backup path between the two, and a traffic data management unit that performs traffic analysis and notifies a traffic analysis result to the MPLS-compatible device. The MPLS-compatible device has a relationship between a label and a priority. A label mapping table management unit that manages a label mapping table that holds information, and switches the low-priority traffic packet from the normal path to the backup path by referring to the label mapping table based on the traffic analysis result Label of the packet Priority-based path switching method characterized by comprising a label swapping processing unit Harikaeru a. 5. The network management system according to claim 1, wherein:
When the number of discarded packets on the normal path exceeds a predetermined number based on the traffic data acquired from the MPLS-compatible device and the number of packets discarded on the backup path is equal to or less than a predetermined number as a traffic analysis result of the LS-compatible device, the MPLS-compatible device 5. The priority-based path switching method according to claim 4, wherein the MPLS-compatible device relabels a packet having a low traffic priority. 6. The priority-based path switching method according to claim 4, wherein the MPLS-compatible device includes a traffic data processing unit that acquires traffic data of a packet and notifies the network management system of the packet data. .