Six Quarks

Six Quarks SQ Probes

About SQ Probes

SQ probes are implemented on specialized hardware driven by a real-time operating system. Probes have hierarchical architecture with the following layers:

Probe architecture

Quality agents interact both with the core and components of the operating system and directly with separate hardware elements: NICs, built-in bypass controller (for probes, providing such functionality), high-resolution timer, storage. Probes make necessary measurements by analysing traffic received from NICs and generating (if needed) specialized test traffic or common network applications traffic. Currently the following quality assurance agents are available:

Interaction servers offer both machine and user interfaces for interacting with a probe.

Quality agents and interaction servers are connected through universal software bus that unifies the interface between top and bottom software layers.

Key Features of Six Quarks Quality Assurance Agents

Six Quarks quality assurance agents, as distinct from other agents presented in telecom market, provide even distribution of test packages in the measured channel within measurement period.

Regularity of test packets is the key feature of Six Quarks quality agents.

Due to this feature quality parameters are monitored uninterruptedly and constantly. This is a distinguishing quality, unlike agents offered by other developers that send traffic in pulsed mode. Such agents aren't able to discover short-time and occasional network troubles.

Ethernet OAM Agent

Ethernet OAM quality assurance agent controls channel quality, in conformity with ITU-T Y.1731. The response party may be any device supporting Ethernet OAM tests as provided by ITU-T Y.1731 specification. Two types of tests are maintained: one-way (ETH-LB) and two-way (ETH-DM).

Ethernet OAM measurements

The following parameters are available for assurance:

For ETH-DM tests the following parameters are also available:

Echo-test Agent

Echo-test agent makes measurements on the network layer generating test traffic and forwarding it to any third party device that supports traffic mirroring using the ICMP, UDP or TCP protocols. The external device sends received traffic back to Six Quarks SQ probe where echo-test agent receives and analyses it.


The following parameters are available for assurance:

Network Quality Assurance Agent

Network detailed quality assurance agent makes measurements (as the echo-test agent does) on the network layer but unlike the echo-test agent, which monitors basic parameters only, the network quality agent provides detailed information of the network quality.

The agent establishes a control connection with the agent on an other Six Quarks SQ probe. After that it generates test traffic and forwards it to the neighbouring probe. The probe that receives test traffic analyses it, then forms and sends response test traffic. After measurement session is over, agents exchange test results via control channel and compose the overall picture of the assured network quality.

Detailed network quality control

The following parameters are available for assurance:

Network Applications Quality Assurance Agent

Network applications quality assurance agent assesses customers' contentment with standard network applications. It is often the only instrument allowing to detect reasons of users' dissatisfaction when overall network quality level is acceptable. The agent controls quality of access to specific network services: clock synchronization (NTP), domain names resolution (DNS) and any network service running on a TCP port, for instance: HTTP, FTP or SSH server.

When making tests the network applications quality assurance agent connects to an existing application server as its client. After the session is over the agent creates a report on its quality.

Network applications quality assurance

The following parameters are available for assurance:

Besides, the following parameters are available for DNS service control:

The following parameters are also available for NTP service control:

Voice over IP Delivery Quality Agent

VoIP delivery quality assurance agent creates control connection to a responding VoIP agent functioning on another Six Quarks SQ probe. After establishing control channel the first agent creates synthetic media traffic according to the selected codec and sends it to the recipient probe. The responding probe, in its turn, also creates synthetic media traffic according to the selected codec. In the end of session agents analyse session results.

VoIP quality assurance

The following parameters are available for assurance:

IPTV Quality Agent

IPTV quality assurance agent controls IPTV image quality using 92 metrics. The IPTV quality agent of Six Quarks SQ probe joins a multicast group. After that it analyses deeply the received MPEG-stream.

IPTV quality assurance

IPTV quality agent examines SPTS and MPTS transport streams, analyses their structure, elementary streams, identifying MPEG2, MPEG4, AVC video codecs and MPEG1, MPEG2 layer 1,2,3, AC3 audio codecs.

Quality parameters are analysed and controlled in conformity with the following protocols and recommendations:

92 metrics are analysed and controlled at the following levels:

Interaction Servers

SQ probes have the following interaction servers:

Server communicating with the core of Six Quarks V supports the following functionality of management of quality agents:

Core interaction server provides interface for sending test results.

The web-interface, apart from the core interaction server functionality, provides the following:

The web-interface allows to set up:

Using 802.1q technology, probe may be managed in a measurement VLAN or in a separate VLAN or through a separate physical port.

The logging server manages various system and measurment logs.

Demarcation of Responsibilities

Six Quarks SQ probes with physical bypass functionality provide physical ethernet bypass mode in case of power failure or administrative probe shut-down, which allows the probe to be installed in-line and provide univocal demarcation of responsibilities of the controlled channel.

Six Quarks probe in-line installation

Different Six Quarks probe models can be installed in line of one or several FE channels, or one or several GE channels. Note that some Six Quarks SQ models do not provide in-line installation capabilities.

L2 VPN Monitoring

The innovative Six Quarks InNet© technology provides monitoring of Layer 2 virtual private networks (L2VPN, for instance, EoMPLS, VPLS), without breaking their integrity and avoiding the necessity of coordination of address spaces between a service provider and a customer.


Six Quarks SQ probes are grouped in three groups.

The group of probes with two-digit indexes includes ultra-compact probes without movable pieces providing network quality measurement accuracy to 1 millisecond. Presently this group includes SQ33 model that replaced SQ23 model in 2013.

SQ probes evolution

The group of probes with three-digit indexes 1xx-5xx includes compact devices providing network quality measurement accuracy to 10 microseconds. Presently this group includes SQ540 model that has replaced SQ100, SQ200 and SQ320 models.

The group of high-level probes with 8xx index. These probes offer the same functional capabilities as the probes of 1xx-5xx series but, unlike the latter, 8xx probes can be installed into a standard 19” telecommunication rack and offer the best productive capacity. The group includes SQ820, SQ875 and SQ887 models.

Probes with 2xx-8xx indexes may be installed in-line.