RU2622632C1 - Method of controlling mechanisms of service quality maintenance in multiservice network - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: method contains the steps of filtering, determining the traffic unit allocation estimates, calculating the mathematical expectation and determining the type of the received traffic. The introduction of new stages: the comparison of the statistical properties of the reference and received traffic, the choice of the output interface, the choice of the queue servicing mechanism based on the known profiles, and the transmission of information on the type of traffic received to neighboring routers allowed the control of the service quality assurance mechanisms in the multiservice communication network.

EFFECT: maintenance of the service quality due to decreasing the queue loading factor in the multiservice network routers at the traffic transfer with the changing statistical properties.

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Description

The invention relates to the field of computer technology and can be used to provide quality of service in a multiservice communication network.

The invention is known "A method and system for promoting traffic flows with guaranteed quality of service (QoS) in a network operating with IP protocol" according to patent RU No. 2271614, H04L 12/28, publ. 03/10/2006, which consists in the fact that, in delivery networks, the route selection function for service packages requiring a guaranteed quality of QoS service is performed by delivery network resource managers at the transmission channel control level. After the route selection is completed in accordance with the busy conditions of network resources, the delivery network resource managers control the border routers so that the traffic flows can follow the path assigned by the resource manager in the delivery network using the multi-level label stack technology. The disadvantage of this method is that it does not take into account the statistical properties of the data stream entering the network, and quality assurance is focused on changing the route of packets.

The closest in technical essence and the functions performed to the claimed is the "Method of analysis of network traffic" - patent RU No. 2362272, H04L 12/56, publ. 07/20/2009. The essence of the known invention consists in filtering by thinning logic circuits with established thinning parameters for the sequence of traffic units entering the telecommunication network and determining an estimate of the distribution of traffic units by occurrence frequency by simultaneously calculating estimates of the occurrence frequency in several ranges of values. Additionally, the mathematical expectation of the arrival time of traffic units is estimated by simultaneously subtracting the values of the traffic units of neighboring ranges, followed by multiplying the results by the relative frequencies of occurrence of the corresponding distributions of traffic units. Then, based on the result obtained, the autocorrelation function of the random process characterizing the arrival time of traffic units is calculated, and the weight coefficients of the autoregressive filter are calculated, based on which the arrival time is predicted to + 1, 2 ... n traffic units. Thus, the prediction of the values of the frequency of arrival of traffic units or the time between the arrival of its individual units. Next, the parameters of the predicted and real traffic are compared according to the Pearson criterion, on the basis of which a conclusion is drawn on the degree of correlation of traffic units, which allows us to determine the fact of a change in the parameters of the current traffic relative to the traffic parameters - the reference.

A disadvantage of the known prototype method is the impossibility of its application to solve the problem of providing quality of service in a multiservice communication network when transmitting traffic with changing statistical properties, that is, the prototype method has limited functionality.

The objective of the invention is to provide a method for controlling mechanisms to ensure quality of service in a multiservice communication network, which allows to ensure quality of service by reducing the load factor of queues in routers when transmitting traffic with changing statistical properties.

The problem is solved in that a method of controlling quality of service mechanisms in a multiservice communication network, which consists in accepting sequences of traffic units, filtering them by thinning logic circuits, determining the distribution of traffic units by frequency of occurrence, calculating the mathematical expectation of the arrival time of traffic units, according to the Pearson criterion, the statistical properties of traffic are compared, according to the invention it is supplemented by the fact that after calculating the mathematical expectation the time of arrival of traffic units set the reference traffic profiles with known values of mathematical expectations, compare the statistical properties of the reference and received traffic, based on the comparison, determine the type of received traffic, select the output interface depending on the type of received traffic, choose another or leave the queue service mechanism unchanged, transmit information about the type of received traffic to a neighboring router.

The analysis of the prior art by the applicant made it possible to establish that there are no analogs characterized by sets of features identical to all the features of the claimed method. Therefore, the claimed invention meets the condition of patentability "Novelty." Search results for known solutions in this and related fields of technology in order to identify features that match the distinctive features of the claimed invention from the prototype have shown that it does not follow explicitly from the prior art. From the prior art determined by the applicant, the influence of the provided by the essential features of the claimed invention on the achievement of the specified technical result is not known. Therefore, the claimed invention meets the condition of patentability "Inventive step".

A method for managing quality of service mechanisms in a multiservice communication network can be implemented as follows.

The first router (Edge Router1, Fig. 5) of the multiservice network domain receives sequences of traffic units (block 1, Fig. 1), filtering traffic units by thinning logic circuits (block 2, Fig. 1). Next, estimates of the distribution of traffic units by occurrence frequency are determined (block 3, Fig. 1).

Procedures for filtering traffic units by thinning logic circuits borrowed from the prototype method allow the formation of a variation series. In the simplest case, the variational series can be represented by Table 1, the first column of which contains all sorts of values (options) x _{i of the} general population, and in the second - numbers n _i - the frequency of occurrence of the i-th value.

The ratio n _i / n is the relative frequency and reflects the weight of a particular value in the sample. The sum of the relative frequencies is equal to one.

The next step is to calculate the expected time of arrival of traffic units (block 4, Fig. 1).

To calculate the mathematical expectation, if there is a variational series, the formula is used

where n is the sample size, m is the number of options.

Then, traffic reference profiles with known values of mathematical expectations are established (block 5, Fig. 1). Based on empirical studies described in [Stepanov S.N. Basics of teletraffic of multiservice networks. - M .: Eco-Trends, 2010. - 392 pp.], Four typical traffic profiles are identified for multiservice communication networks, which can be distinguished by the parameters of the distribution law of packet arrival times to the network. Table 2 presents the option of setting reference profiles, which, based on the characteristics of the traffic of a particular multiservice communication network, can be modified.

To process various types of traffic units on the interfaces of multiservice communication network routers, various queuing mechanisms can be used to ensure quality of service. Among them distinguish [Vegesna, Srinivas. Quality of service in IP networks.: Per. from English - M.: Publishing House "Williams", 2003. - 368 p.: Ill.]:

- the FIFO mechanism (First In, First Out - “first come, first out”) - effective for processing low-intensity traffic (type “A”);

- PQ mechanism (Priority Queuing - a queue with absolute priorities) - effective for processing medium-intensive traffic (type “B”);

- CQ (Custom Queuing) mechanism — effective for processing medium-intensive traffic (type “B”);

- WFQ (Weighted Fair Queuing) mechanism is effective for processing high-intensity traffic (type “G”).

The following is a comparison of the statistical properties of the received and the reference traffic according to the Pearson criterion (block 6, Fig. 1). For this, the values of the calculated mathematical expectations of the traffic are used, based on which the value of the coefficient R _{xy is} calculated by the formula

- его математическое ожидание, y_i - - значения, принимаемые в выборке Y (трафик эталонного профиля),

- его математическое ожидание.where x _i are the values accepted in the sample X (received traffic),

- its mathematical expectation, y _i - are the values taken in the sample Y (traffic of the reference profile),

- his mathematical expectation.

Next, based on the comparison, the type of received traffic is determined (block 7, Fig. 1). The conclusion about the similarity of the received traffic and one of the four reference profiles is made by the maximum value of the calculated Pearson coefficient.

Next, on the basis of the router's routing table, the output interface is selected (block 8, Fig. 1), for which another is selected or the queuing mechanism remains the same depending on the type of received traffic (block 9, Fig. 1).

Next, information about the type of received traffic is transmitted to the neighboring router (block 10, Fig. 1).

To assess the effectiveness of the technical result of the proposed method, a test bench was developed consisting of seven Cisco 2811 routers (Router 1-7) and two multimedia terminals (Terminal 1-2) based on a personal computer (Fig. 2). OSPF, RIP routing protocols are configured on routers.

The experiment to evaluate the effectiveness was carried out in two stages:

Stage 1 - arbitrary configuration of QoS mechanisms;

Stage 2 - setting up QoS mechanisms taking into account the type of incoming traffic.

The load sources were software terminal tools with the ability to change the type of interaction: video, sound, data. The experiment was carried out for two hours with fixing the values of the load factor of the queues K _zag router every 15 minutes. The coefficient K _{zag was} determined by the formula

where k _zi is the used memory size of the ith interface of the router, K _oi is the total queue size of the i-th interface of the router, N is the number of interfaces involved.

Current queue congestion values were determined using the built-in capabilities of the router. The values of the coefficient K _zag for the first and second stages of the experiment are presented in table 3.

The dynamics of changes in the coefficient of congestion of queues in time when using various QoS support mechanisms without taking into account (stage 1) and taking into account the type of received traffic (stage 2) is presented in the graph (Fig. 3).

To calculate the effect of the technical result S of the proposed method, obtained for each of the routers, the following expression is used:

where K ₁ is the average value of the load factor of the queues in stage 1, K ₂ is the average value of the load factor of the queues in stage 2.

Based on the results obtained during the experiment, the average values of the load factors of the queues K ₁ and K ₂ for each of the routers are calculated and are presented in table 4.

The average value of the coefficient of queue congestion on all routers for stage 1 was 0.532, for stage 2 - 0.369.

Thus, the value of the load factor of queues in multiservice network routers, taking into account the type of incoming traffic, on average decreased by 30%, which indicates a positive effect.

The claimed method can be implemented as a distributed device that manages the quality of service policy (Fig. 4-5).

The traffic receiving unit 1 (Fig. 4) implements the procedures of block 1 (Fig. 1), the digital filter 2 (Fig. 4) implements the procedures of block 2 (Fig. 1), the calculation unit 3 (Fig. 4) implements the procedures of blocks 3, 4 (Fig. 1), the block reference traffic profiles 4 (Fig. 4) implements the procedures of block 5 (Fig. 1), the comparison block 5 (Fig. 4) implements the procedures of block 6, 7 (Fig. 1), the output selection block interface 6 (Fig. 4) implements the procedures of block 8 (Fig. 1), a block for determining the current type of traffic 7 (Fig. 4), a comparison block 8 (Fig. 4) and a block for selecting a queuing mechanism 9 (Fig. 4) implement block 9 procedures (f g 1), a transmission unit receiving information about the type of traffic 10 (FIG. 4) implements a procedure block 10 (FIG. 1).

Thus, thanks to a new set of essential features, it becomes possible to control the mechanisms for ensuring quality of service in a multiservice network. The proposed method can be used in subsystems and control units of technological processes in multiservice communication networks.

Claims (1)

A method for controlling quality of service mechanisms in a multiservice communication network, which consists in accepting sequences of traffic units, filtering them by thinning logic circuits, determining the distribution of traffic units by frequency of occurrence, calculating the expectation of the arrival time of traffic units, and comparing Pearson's statistics traffic properties, characterized in that after calculating the mathematical expectation of the arrival time of the traffic units, pour reference traffic profiles with known values of the expectations, determine the type of traffic received, choose an output interface, depending on the type of received traffic, or choose a different mechanism remains the same quality of service, transmitting information about the type of the received traffic to a neighboring router on the basis of the comparison.

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