The public's knowledge and experience of telecommunications services and Internet usage are increasing, which also increases the expectations that the services subscribed will perform well. In a growing telecommunications market, where new services are created and implemented rapidly, end users evaluate operators by the service offerings they provide and by their performance.
The quality of service perceived by the user (usually called QoE – ''Quality of Experience'') is partially determined by general factors such as the activation/connection time and successful access to the service, and partially by the actual connection, meaning the speed, download and upload times, and latency.
The quality of service is also related to different indicators, depending on the type of software application used, since different applications have different requirements.
The most frequent transactions and the differentiating factors for their performance are presented below.
Web Browsing
Web Browsing quality is normally associated with the time needed to locate and download Internet pages through a given web browser. Speed or bandwidth and latency are the factors that help to improve experience in this type of transaction.
File transfer
It consists of the typical download of files, usually of applications, documents, music and images by using a specific file transfer communications protocol, such as FTP or, sometimes, HTTP. The differentiating factor for a positive perception of file transfer is the upload and download speed.
File sharing (P2P)
File sharing or Peer-to-peer (P2P) is a common mode for transferring different types of files, such as music and movies1. Usually associated with 'happy hours', this type of traffic generates high volumes of information and generally reduces the bandwidth available during those periods, where it is also common for operators to implement bandwidth control policies (traffic management mechanisms). The download and upload speeds are differentiating factors in this case.
Gaming
Currently there is a significant variety of on-line games for mobile terminals and for PCs, which require Internet connections that guarantee interactivity with other players. Latency and loss of packets are differentiating characteristics for these connections, in order to ensure a positive perception by users. Upload and download speeds are also important in this perspective.
This study used the applications normally employed for the actual evaluation of the performance indicators from the end user’s point of view, viz.:
a. File transfer – FTP protocol
b. File transfer – P2P protocol
c. Web browsing – HTTP protocol
d. Latency – PING (ICMP protocol)
Below are some definitions for a better understanding of this document's technical content.
Download
Transfer of content from an Internet location to a personal computer.
Upload
Transfer of content from a personal computer to a given location on the Internet.
kbps (kbit/s)
Measurement unit for speed (download and upload).
kB (kByte)
Measurement unit for data volume.
Transfer speed / Web browsing speed
Speed at which data is transferred between computers. Since the volumes of data to be transferred are getting larger and larger, a high speed is desired in order to reduce the transfer times. The webpage used in the tests is made up of an initial page and secondary pages implemented separately, in compliance with the W3C (World Wide Web Consortium), with a mix of images, drawings and texts, and the approximate size of 150kB. This page was associated with four links from the homepage, each with text and an image and an approximate size of 100kB.
Data packets
The data packet is made up of a sequence of bits that are transmitted according to a well defined structure. When it has to be transmitted, data is divided according to those data structures (packets) which contain information that enables them to reach their destination (destination computer). However, packets are grouped so as to retrieve the original information.
Latency
In a data network, latency is defined as the time that a data packet takes to travel from one point to another (from origin to destination). It is fairly common to measure latency through the PING application. This application makes it possible to send an echo request packet, to which the response is an echo reply from the destination. The time elapsing from the sending of the echo request to the reception of the echo reply is defined as latency or one-way delay.
1 The reference to the download of music and movies is made within a context of a legitimate use. It is not the purpose of this study to make any consideration about the contents transferred or the illegal appropriation of copyright. The framework for the assessment of this indicator is strictly within the scope of network neutrality, a fundamental principle that is clearly stated in the European regulatory framework in the field of telecommunications through amendment 46 of the Telecom Package. BEREC is also currently studying the future definition of acceptable and unacceptable practices in the field of traffic management that are currently adopted by the ISPs.
