KR100476649B1 - Dynamic load control method for ensuring QoS in IP networks - Google Patents

Abstract

The present invention relates to a dynamic load control method for guaranteeing quality of service in an Internet Protocol (IP) network. By recalculating and setting the capacity of the IP relay line, it is a method to ensure the service quality of a certain level by maintaining the utilization rate of the relay line within a predetermined range. Regardless of the amount of traffic flowing into the network, there is an advantage in that it can satisfy a certain level of service quality, and there is an advantage in that the network can be operated more economically than when the relay line is set to the maximum capacity required.

Description

Dynamic load control method for ensuring QoS in Internet Protocol (IP) networks {Dynamic load control method for ensuring QoS in IP networks}

The present invention relates to a dynamic load control method for guaranteeing a Quality of Service (QoS) in an Internet Protocol (hereinafter referred to as IP) network, and in particular, a range in which a utilization rate of a relay line is determined by monitoring an IP relay line. It is about how to ensure a certain level of quality of service by keeping it within.

Nowadays, the IP network is an important field of increasing importance as the types of applications such as electronic commerce are diversified using this IP network.

As a result, many efforts have been made in this field over the years to provide a high level of quality of service (QoS) on the Internet.

For example, a weighted fair queuing (WFQ) and random early detection (RED) method is known in a router device. Recently, the Internet Engineering Task Force (MPT), which is defined by the Internet Engineering Task Force (IETF), is known. 'Multi-Protocol Label Switching' or 'DiffServ (Differentiated Service)' is a typical example.

In addition, the basic idea is that the Controlled-Load Service as defined in the IETF maintains the proper quality of service by controlling the traffic flowing into the network to keep the circuit utilization rate low. (Trunk) section is composed mostly of leased lines with fixed bandwidth, in order to operate the trunk section efficiently, it is necessary to adjust the amount of incoming traffic so that excessive traffic does not flow to a specific trunk.

However, the load control service method as described above has a disadvantage in that it is somewhat impractical to restrict traffic due to the nature of the connectionless and open Internet.

SUMMARY OF THE INVENTION In order to solve the conventional problems as described above, an object of the present invention is to implement a method of maintaining a desired line utilization rate by dynamically controlling the capacity of a relay line while leaving incoming traffic intact.

In order to achieve the above object, in the method of controlling the quality of service when providing IP network services to subscribers via an IP network having an Internet Protocol (IP) router and an ATM network having an ATM switch,

An initialization process of setting an upper limit value, a lower limit value, and a measurement period of an IP relay line utilization rate when providing a service through the Internet Protocol (IP) network, and calculating the path of the relay line in advance;

Calculate the utilization rate of the relay line used to provide the IP network service, and continuously monitor the trunk utilization rate of all IP relay line, fault status and traffic capacity between any two routers, and the faults and IP relays generated in the IP relay line. A monitoring process for detecting a case in which the line utilization rate is out of the range of the set relay line utilization rate;

If the capacity of IP relay line is changed and reset for IP relay line outside the upper / lower limit of failure rate and relay line utilization rate, the reset capacity exceeds the physical capacity of ATM relay line. And a reconfiguration process of repeatedly generating and reconfiguring the IP relay line and repeating the monitoring process.

The above objects, features and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a diagram illustrating an IP network configured on a virtual path layer network (LNW) to which the present invention is applied. The layered IP network includes an IP router 1 and an IP relay line connecting the same. The IP relay line corresponds to a virtual path connection provided by the virtual path layer network, that is, a virtual path trail. The advantage of this layered structure is not only to dynamically control the capacity of the IP relay line but also to have rigidity against failure due to the rerouting function of the virtual path connection.

Each IP router 1 of the IP network is connected to each ATM switch 2 of the ATM transport network.

A network management framework capable of effectively managing the layered IP network illustrated in FIG. 1 as shown in FIG. 2 may be arranged in an ITU-T Telecommunication Management Network (TMN) hierarchy. 2, the management function of the layered IP network may be divided into the following layers.

Namely, the service management layer 10 having an IP LInk Reconfiguration Manager (ILRM) 11;

A network / element management layer 20 including an ATM network management system 21 and an IP network management system 22;

It is divided into an ATM switch delegate 31 and a network element layer 30 having a router delegate 32.

Here, the ATM network management system 21 is responsible for the establishment and termination of the virtual path connection corresponding to the IP relay line, resource allocation, and failure status notification. Looking at the process of setting up the virtual path connection, the upper IP relay line is reconfigured. Upon receiving the connection establishment command from the manager 11, the end-to-end location is identified and routed between them, and the appropriate ATM switch delegate 31 is issued to complete the end-to-end trail by generating a unit connection.

When a failure occurs in the trail thus generated, the IP relay line reconfiguration manager 11 is immediately notified. If possible, a bypass path may be established to maintain end-to-end connection.

In addition, the IP network management system 22 collects the utilization rate of each IP relay line and the traffic total information between routers from the router delegate 32 of the network element layer and notifies the IP link reconfiguration manager 11 periodically.

As described above, the IP relay line reconfiguration manager 11 receiving the notification from each network management system 21 and 22 collects the traffic information collected from the IP network management system 22 and the virtual information collected from the ATM network management system 21. It continuously monitors the status information of the path trails and performs link reconfiguration if certain conditions are met.

At this time, the conditions for link reconfiguration are two cases where the utilization rate of the IP relay line exceeds a predetermined threshold value and when the state of the IP relay line is changed. If the utilization rate of the IP relay line exceeds the threshold, the capacity of the corresponding line is increased, or a direct line is created between router devices having a large amount of traffic without a direct line.

When an IP relay line fails, the capacity of each relay line is reset by using the shape information reflecting this, the virtually calculated route information, and the end-to-end traffic information between routers. In this way, the utilization rate of the relay line in the IP network can be maintained within a certain range, and as a result, the overall service quality of the IP network is guaranteed.

Finally, the ATM switch delegate 31 and the router delegate 32 are responsible for management functions in the ATM switch equipment and the router equipment, respectively.

Next, a link reconfiguration operation in the IP network according to an embodiment of the present invention will be described.

The present invention includes an initialization process for calculating a path in advance and determining a main configuration parameter, a monitoring process for collecting key state information and traffic information in the ATM network management system 21 and the IP network management system 22, and IP relaying. It is largely divided into a reconfiguration process of reconfiguring the circuit to adjust the utilization rate.

First, when the initialization process is described, the IP network is represented by a directional graph G (V, E) . In this case, V is a set of router equipment v , E is a set of IP relay line e .

The capacity C (e) of each relay line e is determined in advance by the classical design method and then dynamically controlled according to the proposed method. Considering that most internet applications have asymmetric traffic characteristics, each relay line is assumed to be unidirectional, which means that capacity is determined independently for each direction. And virtually all paths are precomputed for a given graph G (V, E) .

The precomputed route r _{i, j} is the set of IP relay lines that must pass through to reach it, if there is a relay line e _{i, j} that directly connects router i and router j Can be expressed as:

R is any precalculated route r _{i, j} is the set of all S starting, destination router pair: the set of (SD pair source-destination pair) s. S (u, v) represents a set of SD pairs whose paths are calculated in advance via IP relay lines e _{u, v} . That relationship can be expressed as:

Upper limit of relay line utilization , Lower threshold , Measurement interval Is a parameter that must be determined during the initialization process. The upper threshold And lower threshold Is set by the network operator's experience, and the network operator sets the upper threshold. And lower threshold Can be set from time to time.

Secondly, in the monitoring process, the IP relay line reconfiguration manager 11 uses the utilization rates of all IP relay lines during the monitoring process. Traffic across all SD pairs At the same time, it also monitors the link for failure.

The utilization of the relay line is calculated periodically as follows.

At this time, T (t) is the total traffic flowed on the corresponding relay line during the measurement interval [ t-W _meas , t ). The utilization rate thus obtained is the upper threshold. And lower threshold Is compared with the upper limit threshold or lower than the lower limit threshold, the IP relay line reconfiguration manager 11 starts the reconfiguration process. The IP relay line reconfiguration manager 11 performs an immediate reconfiguration process even when the failure state of the IP relay line changes.

Third, when the reconstruction process is described, the reconstruction process is started by two events, a change in the fault state of the relay line and a threshold exceeded, and the relay line reconstruction process will be described with reference to FIG. 3.

When a state change occurs in a state (S1) in which a service is provided through an optimal IP relay line in the IP network (a) The relay line is added and deleted depending on what the state change is. If a fault occurs, delete the edge corresponding to the relay line whose state is changed from the shape graph, and add it (S2) when the fault state becomes normal. The route is recalculated based on the newly constructed graph (S3) and the capacity (bandwidth) S4 required for each relay line is calculated using the traffic data measured therein.

Finally, the bandwidth change request is made to the ATM network management system 21 based on the calculated bandwidth (S5).

In this case, there is a case in which it is impossible to increase the bandwidth to a desired level according to the bandwidth request, which is mostly when the calculated capacity of the IP relay line exceeds the capacity of the physical ATM relay line. In this case, add a new IP relay line between two routers that do not have a direct path. In this case, the router selection criterion is that the path between two routers passes through the corresponding IP relay line, and the traffic volume is higher than that of other router pairs passing through the IP relay line. Then, the reconstruction procedure is restarted based on the new graph (S1).

When the threshold value of the relay line utilization rate is exceeded (b), only the difference starts from the relay line capacity recalculation process (S4) of the above-described reconstruction process, and the rest of the operation is the same as the above description.

For example _, the case where the state is changed in the IP relay line e _{u, v} will be described in more detail as follows.

First, if a failure occurs during the state change, the corresponding relay line is deleted from the shape graph, and if the state is normal during the state change, the corresponding relay line is added (S2). G '= G (E', V) , where to be.

Second, as in the case of the initialization process, the path calculation S3 is performed on the changed graph.

Third, the required capacity for all IP relay lines is calculated (S4).

Α (1 <α <2) is a bandwidth allocation margin factor.

Fourth, the bandwidth change request S5 is made to the ATM network management system 21 based on the calculated capacity.

Fifth, if it is confirmed that the bandwidth change is successful from the ATM network management system 21, it notifies the IP network management system 22 of the IP relay line capacity change and performs the monitoring process. If the bandwidth change for a particular relay line e _{i, j} fails, then the appropriate SD pair ( s = ( k, l ) ∈ S ( i, j )) Select.

ego,

Finally, add the IP relay lines e _{k, l} for the selected source and destination router pairs to the shape graph. Ie G '' = (E '', V). At this time to be. Then start again in the second step.

On the other hand, if the threshold is exceeded, the operation is performed in the third step of recalculating the capacity of the relay line during the reconstruction process, and the next steps are sequentially performed.

As described in detail above, the present invention can dynamically respond to fluctuations in traffic demand, and thus has an advantage of satisfying a certain level of service quality regardless of the amount of traffic flowing into the network. The network can be operated more economically than the setting.

In addition, since the dynamic load control method according to the present invention can be easily applied to the network, it provides an advantage to network operators who have to do business that must guarantee a certain level of service quality based on the IP network. Since there is no need to make changes, it is very useful in the short and medium term depending on the environment and circumstances of the operator.

In addition, preferred embodiments of the present invention are disclosed for the purpose of illustration, those skilled in the art will be able to various modifications, changes, additions, etc. within the spirit and scope of the present invention, such modifications and modifications belong to the following claims You will have to look.

1 is a block diagram showing a layered multi-service network model to which the present invention is applied.

2 is a block diagram illustrating a framework for managing a multiple service network according to the present invention.

3 is a flow chart showing a process of resetting the capacity of the relay line according to the present invention.

<Description of Symbols for Major Parts of Drawings>

1: IP Router 2: ATM Switch

10: service management layer 11: IP relay line reconfiguration manager

20: network / element management layer 21: ATM network management system

22: IP network management system 30: network element layer

31: ATM Switch Delegate 32: Router Delegate

Claims (4)

Claims [1] A method for controlling quality of service when providing IP network services to subscribers through an IP network having an Internet Protocol (IP) router and an ATM network having an ATM switch. An initialization process of setting an upper limit value, a lower limit value, and a measurement period of an IP relay line utilization rate when providing a service through the Internet Protocol (IP) network, and calculating the path of the relay line in advance; Calculate the utilization rate of the relay line used to provide the IP network service, and continuously monitor the trunk utilization rate of all IP relay line, fault status and traffic capacity between any two routers, and the faults and IP relays generated in the IP relay line. A monitoring process for detecting when the circuit utilization rate is out of the range of the set relay line utilization rate through the collected traffic information and the state information of the virtual path trail; Change the IP relay line capacity by resetting the IP relay line beyond the upper / lower limit of the failure and relay line utilization rate generated in the monitoring process, and if the reset capacity exceeds the physical capacity of the ATM network, the new IP Dynamic load control method for guaranteeing quality of service (QoS) in the Internet Protocol (IP) network, characterized in that it comprises a reconfiguration process for repeating the monitoring process after generating and reconfiguring a relay line. The method of claim 1, When reconstructing the IP relay line, the reconstruction process when a failure occurs in the IP relay line in use, Reconstructing the shape graph by deleting the failed relay line link; A second step of virtually calculating all the router-to-router routes based on the reconstructed shape graph; A third step of calculating necessary capacity on the basis of the traffic capacity data for all of the calculated IP relay lines; Requesting a bandwidth change to the ATM network and the IP network to realize the recalculated capacity; And selecting a new link to be added when the bandwidth change request fails, and sequentially repeating from the first step, and if the bandwidth change request succeeds, repeating the monitoring process. Dynamic Load Control Method for Guaranteeing Quality of Service in Internet Protocol (IP) Networks The method of claim 1, If the IP relay line utilization rate used during the IP relay line reconfiguration is out of the upper / lower limit, the reconfiguration process is performed. A first step of recalculating required capacity on the basis of the traffic capacity data for all the IP relay lines in use; Requesting a bandwidth change to the ATM network and the IP network to realize the recalculated capacity; And selecting a new link to be added when the bandwidth change request fails, repeating the process of reconfiguring the shape graph, and repeating the monitoring process when the bandwidth change request is successful. Dynamic Load Control Method for Guaranteeing Quality of Service in Internet Protocol (IP) Networks The method of claim 2 or 3, Dynamic load control method for guaranteeing the quality of service (QoS) in the Internet Protocol (IP) network, characterized in that the required capacity of the relay line is calculated using the following equation. expression) ( : Capacity of the relay line e _{i, j} S : set of all departure, arrival router pair s W _meas : measurement time interval α (1 <α <2) E : set of IP relay lines e e _{i, j} : relay line directly connecting router i and router j )