Ready for VoIP: Network Management Architectures: Telchemy
Telchemy's claim to fame is its embedded software, built into many phones and infrastructure devices and deployed by a host of customers.
Telchemy, Inc., headquartered in Duluth, Georgia, develops technology that enables enterprises and service providers to deploy and manage voice and video over IP, streaming audio and video, and networked gaming services over their networking infrastructures.
Telchemy's products provide real-time visibility of service quality, estimates of user-perceived Quality of Service (QoS), and detailed analysis of the root cause of quality degradation. Their software technology can be integrated by equipment manufacturers into a wide range of products, ranging from consumer electronics devices to large telecom systems; it monitors every call and detects problems in real time.
The company was founded in 1999, and since that time has developed a number of products that have been integrated into IP telephones, gateways, probes, analyzers, and routers, and deployed by telephone companies, cable service providers, ISPs, and major enterprises. Telchemy's customers include AudioCodes, Brix Networks, Ditech Communications, Empirix, Ixia, NexTone, and Nortel Networks.
For passive monitoring, the architecture includes agents embedded into endpoints, distributed probes, and other mid-stream devices.
For active testing, distributed software test agents generate voice, video, and network diagnostic traffic to each other and report quality/performance metrics back to a central reporting and configuration interface.
On the embedded side is Telchemy's core technology, a passive monitoring performance analysis agent called VQmon. This agent generates listening and conversational quality Mean Opinion Scores (MOS) and R factors, plus a wide range of diagnostic data, and then makes that information available through an API (application programming interface).
VQmon is based on the ITU-T E Model, but with many extensions that improve the accuracy. The product comes in three versions: VQmon/EP (End Point), which is integrated into IP phones, gateways, and cellular handsets; VQmon/SA (Stream Analysis), which is integrated into mid-stream devices like probes, analyzers, and routers; and VQmon/HD, for video stream analysis, to be integrated into IP set-top boxes, videoconferencing equipment, and so on. VQmon is in wide use by equipment providers, with over 36 million units currently licensed.
Telchemy's OEM system products are targeted for either passive or active monitoring, with one additional product for report collection/mediation.
There are two products for passive monitoring. The SQprobe is a software probe for the Linux operating system, incorporating VQmon/SA. SQprobe passively monitors a 100-BaseT/GigE link and detects VoIP/IP video calls/sessions, reporting MOS/R-factor scores, burst/gap statistics, degradation factors such as packet loss and delay, plus transport metrics, and provides them in a Web user interface or via SNMP, as shown in Figure 1.
In addition to the metrics it collects by monitoring the stream directly, SQprobe collects the Real Time Control Protocol Extended Reports (RTCP XR-see ftp://ftp.rfc-editor.org/in-notes/rfc3611.txt) sent by endpoints such as IP phones, if they are running VQmon/EP, and correlates the data together.
Voyager is also a probe incorporating VQmon/SA, but it is a self-contained plug-and-play device designed for small workgroups and branch offices. It comes with a built-in passive tap, and includes a DVQattest test agent that can be used to generate active VoIP calls. Voyager has a GUI similar to SQprobe's and also provides data via SNMP (see Figure 2). For example, an enterprise with one main location and several branch offices (like a bank) might want to deploy SQprobe in the main office and put a Voyager unit in each branch, in order to monitor calls coming into and going out of each location.
For active testing, Telchemy has developed DVQattest, a distributed active test application for VoIP and IPTV/IP videoconferencing that incorporates VQmon. This product is available in two versions. DVQattest/EN is designed for enterprise network environments, installed on Linux/Windows/Mac PCs or servers, where it runs in the background as a daemon or service. DVQattest/RE is designed for residential VoIP/IPTV or hosted PBX service provider applications, with agents that are placed on a public Web server on the service provider's network, and then downloaded to subscriber desktops as needed. Both versions of DVQattest includes expert analysis with a text diagnosis of problem conditions detected, plus a list of specific degradation factors and the percentage of quality degradation attributable to each (see Figures 3 and 4).
In addition, Telchemy offers SQmediator, a central report collection/mediation application. SQmediator collects endpoint reports, analyzes them, and provides quality scores, performance metrics, and expert analysis/diagnostic data for individual calls and video sessions. Performance data can be viewed in a Web-based GUI or accessed via SNMP or a custom API.
Further details on the Telchemy architecture and products can be found at http://telchemy.com/. Our next tutorial will continue our examination of vendors' network management architectures.
Mark A. Miller, P.E., is President of DigiNet Corporation®, a Denver-based consulting engineering firm. He is the author of many books on networking technologies, including Voice over IP Technologies, and Internet Technologies Handbook, both published by John Wiley & Sons.
Article courtesy of Enterprise VoIP Planet, © DigiNet Corporation, All Rights Reserved