Introduction
With the development of Internet infrastructures in the country, there has been an increase in the level of access of individuals and sectors of the Iranian society to this global network. And, considering the terminology that is commonly used in the virtual world while connected to the Internet, there are usually many uncertainties and questions raised for the public about how to calculate the actual speed of the Internet and what terms such as kilobit, kilobyte, and contention ratio mean.

In this article, we have tried to give an appropriate response to all of these ambiguities in the simplest language possible.
The actual speed of Internet connection, a big misunderstanding!
Firstly, we will explain the most commonly used notion that most users often find confusing; it means, the speed of the Internet connection and how it is calculated.

In most cases, users assume Internet speed equals the speed in Kbps that Internet service providers (ISPs) use to name and sell Internet services to their subscribers.

When a subscriber submits a request to an Internet service provider to subscribe to an Internet service, the service provider offers the applicant, as a natural or legal user (home users or companies and organizations), different services at 128, 256, 512 and … in a kilobit per second measurement unit, and in proportion to their need.

It is important to note that the speed of these services is calculated in Kilo bit per second, in which the word “bit” is marked with the lower-case character of English letter “b” and is displayed as Kbps.
On the other hand, there is another unit called Kilo Byte per Second, in which the word “Byte” is marked with the upper-case character of English letter “B” in KBps, and is usually visible when downloading and receiving files from the Internet. (Each Kb is 1024b and each KB is 1024B)

Given that every 1 Byte of data is composed of 8 bits, each service speed provided by Internet service providers to subscribers should be divided by 8 at the time of use to be converted into the speed visible when the user downloads files from the internet.

In other words, Internet users in the virtual world often see their connection speed in various software (download and speed management software) in kiloBytes per second (KBps), and this may concern them that for example, while the Internet speed is 128 Kbps, why the software shows the internet connection speed as 16KBps during connection.

For other Internet services, it is also sufficient that the service speed in kilobit (Kbps) that the Internet service providers use to name their services is divided by 8 to find out the service speed in KBps (KiloBytes per second), and user’s download speed can be seen in this unit.

For example: The speeds displayed when downloading files from the Internet for 256Kbps and 512Kbps (two hundred and fifty-six Kbps, and five hundred and twelve kbps) are 32KBps and 64KBps respectively (thirty-two, and sixty-four KBps).

A recent survey shows how informed a number of subscribers to 128Kbps Internet Services (one hundred twenty-eight Kbps) are of the real speed of the internet. The following pie chart shows the results of this survey:

Interestingly, only 10% of subscribers knew about the real speed of their service and its unit of measurement!

35% of respondents mistakenly considered the speed of their service in kiloBytes per second (KBps).

25% did not know the meaning of Internet speed units such as Kbps (kilobits per second) and KBps (Kilo Bytes per second).

The other 30 percent also had no answer to this question.

A shared service or a dedicated service, that’s the question!
Another important point that most users and subscribers do not pay much attention to before and after purchasing the Internet subscription is if the internet service is shared or dedicated.

Generally, the Internet services are divided into shared and dedicated services. Natural and legal users (home users or companies and organizations) can, depending on their need and rate of use, have any of these services at different speeds, and use it based on its shared and dedicated features.

According to the Resolution No.152 of Communications Regulatory Commission, which is the trusted Internet agency in the country, all Internet companies are required to offer their shared services with a contention ratio of 1 to 8 and their dedicated services with a ratio of 1 to 1.

This means that when a home user of a 128Kbps shared service receives its Internet service, the bandwidth of this service, due to its shared nature, can be shared among up to 8 users, and thus the speed of this service during peak hours may decrease to one eighths of the initial speed and be as low as 16Kbps (sixteen Kilobits per second).

Of course, it should be noted that most Internet service providers, in order to win their subscribers’ satisfaction, are providing the subscribers of shared services with features the same as those of dedicated services.

The contention ratio of dedicated Internet services, which due to its cost and greater number of users is mostly used by companies and organizations, is 1:1, which means that the speed and bandwidth of the service is provided to only one subscriber individually and is not shared with other subscribers. In other words, the subscriber to a 128Kbps (Kilobits per second) dedicated service can use their Internet service 24 hours a day at a speed of 128Kbps (128 Kilobits per second).

This is an important point that most internet users do not pay attention to, although it is clearly stated in the Internet service contract, and they expect to be always and 24 hours a day (even during the peak hours in which the bandwidth is congested by the users) connected to the Internet at the speed stated in their Internet service contract.

Considering the above explanation, this is not an accurate assumption, and although the speed of the service at most hours of the day is higher than the speed defined in the contract, sometimes the speed may decline to one eighths of the nominal speed of the service. This condition is part of the terms of the shared services.

Conclusion; calculation of the speed of Internet services in the country!
Considering the issues that have been described about the contention ratio of Internet services in the country as well as the difference between bit and Byte:
We think it is possible for users to miscalculate the speed of their service in these units (Bit / Byte) and misunderstand the contention ratio.

Thus, users should be aware that these two items are considered separately for Internet services, and they should be used together to calculate the speed of the service.

Supplementary Note; Service Level Agreement (SLA)
In order to ensure that Internet service providers maintain the quality of Internet services, Communications Regulatory Authority (CRA) in its meeting No.177 has specifically identified cases that are referred to as the Service Level Agreement (SLA).

A service level agreement is a bilateral contract between the internet service provider and the Internet service receiver, according to which the quality parameters of the agreed services are guaranteed, and all Internet service providers in the country are required to implement all the related terms. The details of this agreement are described in the Commission No. 177 of Communications Regulatory Authority, as “The Terms and Conditions of the Service Level Agreements (SLA)”, and users may, in the event of a provider’s failure to provide Internet Services with specified parameters, request for a compensation and follow up their request through Communications Regulatory Authority.