QoS – Quality of Service

QoS (Quality of Service) is one of the most important functions of VAS EXPERTS DPI. This is achieved by the ability of DPI technology to share all traffic by priorities, providing wider bandwidth to certain applications and protocols.

QoS is applied most of all in providing to the subscriber of IP telephony services, IPTV, video conferencing and other services sensitive to traffic delays.

Availability and quality of service provided are one of the main indicators of the work of a telecom carrier or an Internet provider. Stuttering sound, video with colour squares, slow downloading of pages are one of the most annoying factors for the user, from which it can be saved improving QoE (Quality of Experience) thanks to the QoS function of the VAS EXPERTS DPI system.

What does QoS solve


Hierarchy of Prioritization

To ensure Quality of Service (QoS), VAS EXPERTS DPI allows to prioritize traffic at all stages of its delivery to the user:

  • by common channel;
  • by the subscriber’s tariff;
  • by VLAN and ports if there are several UPLINKS (channels to upline provider) and necessity in balancing.

Traffic Mapping by Changing the Priority Field

To ensure the required QoS on the router or shaper, VAS EXPERTS DPI can change the priority field of the packets passing through it after defining a protocol or an autonomous system. The following fields are supported:

  • DSCP/TOS in the headline of IP packets,
  • priority in VLAN and QinQ packets’ headlines,
  • traffic class in headline MPLS packets.

Tariff Plans for Users

VAS EXPERTS DPI allows to limit the bandwidth for the user (within the tariff plan) and to prioritize traffic within this bandwidth. This allows to provide high quality of service for demanded applications, even if the same IP address is assigned to several users, one of which creates uneven download of the channel (for example, by a running torrent client), that leads to a deterioration in the quality of sensitive services: streaming video, telephony, TV. The assignment of high priority to these services ensures their stable operation and high quality.

Uplink Expenses Decreasing and QoE Increasing

In order not to buy additional UPLINK speed during peak hours (evening time), priority setting and VAS EXPERTS DPI QoS function give low priority to background applications (torrents, file downloads, updates, etc.) and a higher priority to online video, web browsing, online games. Thus, during peak hours, the user will not notice quality deterioration, and the UPLINK speed will not be exceeded.

Control over “Shelf”

SCI DPI allows to control approaching to the upper boundary of the channel strip (“shelf”) and prioritize traffic by protocols and directions so that low-priority traffic is forced out of the strip in favor of a high priority.