Learn About the Ways to Analyse the VoIP Networks Performance

Learn About the Ways to Analyse the VoIP Networks Performance

Introduction

Most of the modern active IT infrastructure monitoring systems are based on the same principles. The monitoring system in some way interrogates the equipment or software, obtains the result and compares it either with the template or with predefined maximum permissible values.

For example, to determine the availability of an SMTP server, the monitoring system must connect to the server to the port 25 of TCP, pass the string “helo my.monitoring.com” to receive a string in response and disconnect from the SMTP server. Next, it must check whether the server’s response string contains a three-digit code at the beginning starting with the number 2. If this is true, then the server is live, if not, the system should give an alert. In fact, this is a method of comparison by the template.

Another example is checking the CPU usage. The monitoring system, most often on SNMP, polls the server, receives the value of the current processor load, and compares it with the maximum permissible maximum value, let’s say 80. If the processor is loaded by more than 80%, the monitoring system should give an alert. This is a method of checking the maximum permissible values of the variables being questioned.

In any case, during the configuration of the monitoring system, you need to set clear criteria for what should be considered the normal operation of your equipment or software, and what is a malfunction, or a situation that could lead to a failure in the near future.

This principle of monitoring works in most cases. However, sometimes, to set criteria for what to consider a failure and what is normal work is too difficult or even impossible.

How does the transit VoIP works

One of the monitoring tasks, which is not solved by standard methods, is the task of monitoring the quantitative and qualitative parameters of the transit VoIP. Before describing how a monitoring system based on forecasting works, it is necessary to describe how the transit VoIP provider works.

There are many nuances explanation in transit VoIP requiring a long. Therefore, the description will be on a primitive level.

This issue should not be considered at the level of the end user – the person who calls, but at the level of the  VoIP service providing companies. From this point of view, two companies participate in the provision of the service. The first, company let’s say company A, is a consumer of VoIP traffic, whose customer initiates the call, the second, company B – the provider that terminates the call.

The supplier usually delivers one or more directions. A direction is called a group of telephone codes, sold at a certain price. Now there are about 1300 directions in the world.

The consumer company usually provides its customers with all directions – called A-to-Z destinations. Therefore, the consumer needs to set up the contracts with many suppliers of different directions, and then route the directions to different suppliers. It is rather difficult to perform.

On the other hand, the supplier is interested in attracting as much traffic as possible. However, this is associated with a large number of contracts and potential financial risks, for example, one or more of companies may not pay for the traffic consumed.

Therefore, both suppliers and consumers benefit from working with the company as a transit agent, which, strictly speaking, does not generate and does not supply VoIP traffic, but connects them with each other.

In fact, instead of the interconnected structure of interaction between suppliers and consumers, the structure represents a star, in the center of which is a transit country.

The company, with the described monitoring system, has about 250 suppliers and 250 consumers. The company provides A-to-Z directions, in total about 1500 names of directions are registered in the billing system.

 

It is extremely important for the transit company to monitor the work of the consumers, suppliers, and destinations. Besides, this should be performed in the context of each consumer, supplier, and direction. In the short term, in the case of a failure, the transit company loses its margin. In the long term, everyone is interested in a high level of service.

Now, after the outline of the transit system, we will formulate the task of the monitoring system.

The task of the monitoring system

When it comes to VoIP monitoring, it usually means monitoring such parameters as jitter, delay, packet loss, MOS. Cisco has a strong technology.

However, for the transit VoIP operator, the use of such technologies and the analysis of such metrics is not suitable. Naturally, the transit VoIP operator analyzes both the percentage of packet loss, and jitter and delay, before the partners, but he does this only after detecting a failure. The failures themselves are identified by analyzing other parameters, such as:

  • The total number of minutes.
  • The total number of calls.
  • ASR (Answer Seizure Ratio) is defined as the ratio of successful calls with a non-zero duration to the total number of calls.
  • ACD (Average Call Duration) is the average duration of a call.

The first two parameters are quantitative, the last two are qualitative. It should also be noted that monitoring systems usually poll remote devices in one way or another, the described monitoring system uses CDRs (Call Details Records) as a data source. A CDR-file is a text, each line of which contains information on one call or attempt to make a call. The level of detail for a specific call can be different, it all depends on what CDR equipment. A quality CDR can contain about 100 parameters, it contains not only information about who called, where the call was made, the duration of the call and the call completion code, but also in the case of VoIP, parameters such as jitter, codecs, packet loss, MOS, and others.

Let’s count how many total values the monitoring system should check for a potential failure. It is necessary to analyze the parameters for 250 suppliers, 250 consumers, and 1500 destinations. For each supplier, consumer and direction, it is necessary to check 4 values, in total we will get:

250 * 4 + 250 * 4 + 1500 * 4 = 8000

However, the point here is not in a relatively large number of quantities that need to be checked. The fact is, each of the partners and each direction is unique in its own way, moreover, the parameters of each partner’s work and directions depend very much on the time of day.

The method of forecasting why this should work

Despite the fact that each direction and partner is unique in its own way, the quantitative and qualitative parameters of the work are predictable. For example, let’s consider the schedule of one of the directions for three consecutive days, for clarity, we depict every day on the same chart in different colors.

It is logical to assume that in the same way, calls will be distributed to the direction and on the fourth day. In fact, we can predict how the direction should behave, and if the direction behaves differently than predicted, give an alert about a potential failure.

Thus, the task can be solved by writing software that can predict. There are many methods of forecasting for the current moment. However, it is difficult to implement one of the prediction methods programmatically; it is more profitable to use the box-product.

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Posted on: May 17, 2017Ana Nichols