RTP Traffic Quality Analyzer

Probe for the Measurement & Analysis of RTP Quality Metrics.

RTP Traffic Quality Analyzer

Overview

The RTP Traffic Quality Analyzer is a passive network monitor and stream emulator for the RTP signaling specification as defined by RFC 3550. It is a SAFIRE based application able to measure & analyze RTP quality metrics of both audio and video streams on VoIP networks, as well as originate and terminate RTP streams.

The stream browser monitors the network traffic, automatically detecting & tracking RTP streams. The browser gives an on-line overview of the real-time status of active streams with quality metrics, such as jitter, delay & packet loss. The SAFIRE Weighted Quality Index (SWiQI) presents a color-coded, 'at-a-glance' summary of the quality metrics per stream and for the total RTP traffic. Detailed information for a stream can also be presented in real-time charts or saved as a report (HTML).

The unique Node Explorer gives a complete overview of every node in the network. It allows the user to drill down through the IP subnets all the way to the port level.

Network Overview and Node Explorer

The network monitor includes a VoIP protocol analyzer for on-line capture & decode of the signaling in real-time, both during quality measurements and as a stand-alone tracer for live systems.

The RTP Traffic Quality Analyzer is suitable for quality & performance measurements in NGN environments and of components such as soft-switches, VoIP clients, routers & gateways.

The emulation features run in parallel to the analysis functions. The application can in two modes: standalone or under the control of a signaling tester.

Key Features

• Easy to use, all-in-one RTP troubleshooting and analysis
• Emulation of RTP streams
• Analyzes video and audio streams
• Can run standalone or as part of a test harness or call analyzer
• Performs path validation using DTMF
• At a glance evaluation using SWiQI
• Drill-down into the network to the stream level for detailed analysis
• Real-time protocol analysis for detailed fault diagnosis
• Runs on a Notebook

Description

The RTP Traffic Quality Analyzer is designed for engineers requiring an all-in-one solution for RTP quality analysis and testing in Ethernet networks. Whether for troubleshooting or ongoing quality assurance, the system allows the user to focus on a problem without worrying about protocol specifics.

The system enables network engineers to evaluate all aspects of RTP traffic in modern NGN networks finding application in the following areas

• Identification of poorly performing network segments and subnets
• Evaluation of changes and upgrades in the network infrastructure
• Testing of client implementations at development stage and after deployment
• Control and observation of VoIP test methods
• Measurement of network load impact on RTP QoS

RTP Traffic Quality Analyzer can recognize all RTP audio and video payload types, including:

• MPEG 1, 2, 4, DIV1, DIV2, DIV3, H263, H264, WMV, MJPEG
• G.711a, G.711u, iLBC, GSM 6, G.729(a,b), G.723.1
• MPEG 1, MPEG 2 TS, MPEG 2 PS, OGG, RAW, WAV, MOV, MP4 and ASF encapsulation

Video analysis is limited to streams with a constant bit rate.

The payloads can be recorded to disk and replayed using the built-in Stream Generator.

Network Details including RTP Overview

The unique Node Explorer allows the user to drill down through the IP subnets all the way to the port level. At each in level, the cumulative average quality of the subnet is indicated allowing quick visual evaluation of a network and aids in the location of problem nodes.

Node Explorer offers unique insight

A real-time Top 5 and Flop 5 table allows network engineers can localize poorly performing network segments and subnets.

TOP 5 and FLOP 5 Endpoints Table

Conventional Stream List

Quality Analysis

Quality is calculated by statistical analysis of the RTP and RTCP signaling on the link. The voice payload itself is not considered - this allows the system to analyze hundreds of RTP streams in real-time on standard PC hardware.

Based on this analysis, the SWiQI (SAFIRE Weighted Quality Index) is used to give a subjective quality value for each stream. This value is mapped to the ITU-T G.107 E-Model and ITU-T P.800.1 MOS Score scale, including recommendations in ITU-T G.113. Video analysis is limited to streams with a constant bit rate.

Stream View showing Real-time Quality Evaluation

The information is displayed in clear, easy to interpret tables and graphs.

Stream View showing Statistical Details

The system presents the data in a well structured graphical user interface. The overviews give quick insight into the network and any possible quality problems. For closer investigation, the user can drill down to the stream level and analyze individual stream attributes both textually and graphically. The real-time charts allowing visualization of short and long term trends.

Stream View showing RTP Characteristics in Charts

RTP TQA has built-in report generation facilities allowing the user to create a performance snapshot in HTML format.

Example Report

RTP Emulation

In standalone mode, RTP TQA allows the user to manually originate and terminate a single RTP stream, and perform DTMF transmission and detection.

For more advanced RTP requirements, it can be integrated with a VoIP signaling tester. In this case, it provides the entire RTP/RTCP functionality for call test scenarios, as well as enabling path validation using DTMF tones.

By using the stream record feature built into the stream analyzer, reference audio and video RTP streams can be recorded to disk and then replayed using the emulator. Streams with variable packet size and packet frequency are supported.

Stream Generator dialog

Erroneous RTP streams may be generated, include packet loss, out of sequence packets, duplicate packets, header inconsistency.

Stream Generator error control

These features are controlled from within the VoIP test scenarios using a simple API.

DUT Performance Evaluation

For measuring the performance of a NAT gateway, or router, multiple instances of RTP TQA can be deployed.

In this configuration, the traffic quality and various other network characteristics can be measured on each side of the DUT, allowing direct performance evaluation.

Quality Metrics

Measurement
Jitter
Packet Loss
Burst Packet Loss
Out Of Order Packets
Round Trip Time (RTCP)
SWiQI (SAFIRE Weighted Quality Index)
RTCP-XR	Option
MOS Equivalent (ITU-T P.800.1)
E-Model Equivalent (ITU-T G.107)

NOTE: Video analysis is limited to streams with a constant bit rate

System Requirements

Example System performance

Related Products & Services

• SAFIRE World also has a complementary SIP Signaling Tester and SIP Call Analyzer
• Professional engineering services for project development & test execution
• Training workshops (customized agendas on request)
• OEMs, contact us for bundling offers!