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Product Reviews
May 2003


Tenor CMS

Quintum Technologies
14 Christopher Way
Eatontown, NJ 07724
Tel: 732-460-9000
Web: www.quintum.com

Price: CMS240 starts at $21,500; CM960 starts at $25,850

Editor's Choice Award

RATINGS (0-5)
Installation: 4.75
Documentation: 5
Features: 5
GUI: 4
Overall: A-


With VoIP becoming more prevalent, especially with companies looking to shave costs in their phone bills, purchasing the right VoIP gateway that is standards-based and won�t become obsolete are two critical assessments a CIO or CTO needs to make before purchasing.

VoIP gateways are experiencing good growth, especially with companies looking to shave costs anywhere they can in this tight economy. We all know that VoIP technology can reduce costs, so the question becomes �Which VoIP gateway do I purchase?� There are several high-end VoIP gateway players, such as Cisco, Nuera, and Quintum, as well as low-end players (1�8 ports) such as Mediatrix or Quicknet -- Quintum also targets the low-end with port densities that start at two ports. Regardless of whether you are looking for small port densities or larger port densities, there are two important �truths� that apply to both. First, you want to make sure that you purchase a VoIP gateway that is standards-based and interoperates with other vendors� gateways so that you don�t run the risk of the gateway becoming obsolete. Secondly, you want to choose a gateway that is firmware-upgradeable to the latest codecs or Internet telephony standards, such as SIP or H.323.

TMC Labs checked out Quintum�s CMS240 two-slot gateway, which supports up to eight T1/E1/PRI Spans per chassis (up to 240 DS0s). Another eight-slot chassis model is available called the CM960, which supports 32 T1/E1/PRIs per chassis (up to 960 DS0s). Functionally they are identical other than the scalability. We tested the two-slot chassis, which is 1U in size, and can be easily rack mounted. We should point out that with these two models of varying port densities, Quintum can target both the enterprise with the smaller model and service providers/ISPs/ITSPS/carriers with the larger model.

DOCUMENTATION
We were quite pleased with the documentation, which came on a CD-ROM with a few Acrobat files. The manuals were quite extensive -- some of which were over 300 pages. Fortunately, within Acrobat you can view the chapters on the left-hand pane and quickly find the topic you are looking for, or you can simply use the search for keyword feature. Also, an index was available in the user�s guide making it easy to lookup certain features. Overall, we were quite pleased with the documentation: That earned a perfect 5 rating.

FEATURES
The CMS can configure routes and set priorities without the need for an external routing server. Intelligent call routing by the CMS can be based on phone number, least cost routing, etc. For additional flexibility and increased QoS management of routing as well as the overall network of Tenors, an external Call Routing Server can be added to the network. The CRS allows not only for LCR, but for source based, best pattern match, domain priority, circuit matching, Answer Seizure Ratio, etc. The CMS product line features advanced call routing utilizing Quintum�s external VoIP Call Routing Server, which provides scalable, centralized network routing control and administration for larger networks. It also provides network-wide routing flexibility including QoS routing, least cost routing, source-based routing, and extensive network routing statistics/report generation. CMS supports Interactive Voice Response (IVR), which has multiple user selectable languages and prompts. In addition, CMS supports IP TOS (Type of Service) for QoS support. This product supports applications such as wholesale VoIP termination, tandem switching, call centers, IP local loop, Least Cost Routing, and calling card applications.

We should point out that both the CMS240 and the CM960 are identical in feature-set with the only difference being scalability. Listed below is a list of other features supported by the CMS product line.

� SelectNet Auto-switching between VoIP and PSTN if certain threshold parameters are met;
� Intelligent Call Routing;
� VoIP and Tandem Circuit Switching;
� Integrated H.323 gateway and gatekeeper;
� Up to 960 VoIP channels (in the CM960);
� Up to 32 T1/E1/PRI Spans per chassis (up to 960 DS0s) (in the CM960);
� IVR/Radius AAA Compliant (Multilingual IVR);
� Support for external Quintum Call Routing Server;
� SNMP support;
� Automatic call type detection: Voice/Modem/Fax;
� Answer and Disconnect supervision;
� Trunk group support;
� Public and private dial plan support;
� Automated load balancing;
� Pass-through support for calls to 800, 911, 411, etc.;
� Automatic appending and stripping of digits to dialed numbers;
� Call Blocking;
� (Planned for end of 2nd Quarter) SIP User Agent, SIP Redirect and Registrar Server;
� Adaptive Voice Activity Detection (VAD) with Comfort Noise Generation (CNG);
� Adaptive Jitter Buffer; and
� Carrier Grade Echo Cancellation: ITU Rec. G.165/G.168, up to 128 msec tailsize.

OPERATIONAL TESTING
Conserving bandwidth is a major concern when it comes to VoIP applications. The more voice conversations you can squeeze into a given bandwidth, the better. All things being equal, TMC Labs found that Quintum can �squeeze� more voice conversations into a given T1 circuit than many competing products. The reason is their �PacketSaver� technology, which combines voice packets from several calls into one IP packet by maximizing the data utilization of the packet, which often has unused overhead space. Essentially, the way it works is that PacketSaver multiplexes multiple individual VoIP sessions into consolidated IP packets, thereby maximizing the utilization of the IP packet. By reducing the IP packet overhead you can reduce the total amount of bandwidth needed to support VoIP calls. As a side effect, because PacketSaver reduces the total number of packets used for VoIP traffic, it also reduces the chances of packet loss -- another factor that can affect voice quality.

In addition to this unique �PacketSaver� technology, Quintum also is unique in its ability to intelligently switch calls from VoIP to a PSTN line if jitter, latency or packet loss reaches a certain threshold. This happens completely transparently to the caller. All the caller may hear is brief period of silence while the call is switched from IP to PSTN. We tested this functionality on several of Quintum�s past and present products and it works quite well. This helps alleviate �quality of service� concerns that customers may have in purchasing a VoIP gateway.

As if these two unique features weren�t enough, Quintum threw us a curveball when they told us that they support H.323 over NAT. As many of us in the VoIP industry know, H.323 over NAT is a HUGE issue. Well, Quintum solves that problem with their �NATAccess� feature, which overcomes the problem of NAT firewalls not correctly translating internal IP addresses into public addresses when a VoIP call is established with an outside party.

One final unique feature of the CMS gateway is that unlike most (if not all) VoIP gateways, the CMS supports TDM-to-TDM (i.e., one T1/E1/PRI to another T1/E1/PRI) in addition to its VoIP-to-TDM and TDM-to-VoIP support. What does this mean? Most gateways require that at least one leg of the trip go across IP. Quintum does not limit you in that fashion. Keeping calls 100 percent on the PSTN can be useful if the calls are local (no phone charges) and you don�t wish to use precious IP bandwidth or perhaps there is too much network congestion to perform VoIP calling. The most common scenario is a call might come in one PRI and the cheapest route is out another PRI.

In our tests we determined that Quintum can do DTMF in-band or out-of-band and they support G.729ab, G.726 ADPCM, G.711 as well as G.723.1a (default). We performed several test calls and the quality was excellent over our shared T1 Internet connection. We didn�t experience any choppiness in any of our test VoIP calls.

In addition, a critical feature is that it supports A-law to �-law conversion on both the VoIP and TDM interfaces. The system also has a �backup� config database file if you need to restore a prior setting. It�s a simple file directory structure, so other manual backups can be performed on-the-fly.

ROOM FOR IMPROVEMENT
With a little practice, we were able to quickly navigate the GUI, which utilizes a CLI (command line interface). Nevertheless, we�d still like to see a Web or Windows-based interface for even more flexibility. For instance, a Windows-based interface would allow for quickly dragging-and-dropping configurations from one Quintum gateway to another for quick cloning. Fortunately, by the time you read this Quintum should have a Windows-based interface. Also, we�d like to see SIP support, but once again, Quintum told us it would be available by the time you read this. Thus, in essence, we couldn�t find anything to complain about that Quintum hasn�t already addressed by the time this review goes to print.

CONCLUSION
We mentioned that there were two important �truths� before purchasing a VoIP gateway. That is, it must be �standards based� and be �firmware upgradeable.� Well, Quintum passes with flying colors as it support H.323 and it is firmware upgradeable, which will allow SIP to be added by the time you read this. But Quintum didn�t stop there. Unique to Quintum is that they can seamlessly switch from VoIP to PSTN if the call quality degrades. The ability for a VoIP gateway to perform TDM-to-TDM switching is also unique to Quintum�s CMS. Combine that with Quintum�s ability to efficiently multiplex multiple VoIP calls into a single IP packet, and you�d be hard pressed to find a more robust and feature-rich VoIP gateway on the market today. Overall, TMC Labs was extremely impressed with the Tenor CMS product line and wouldn�t hesitate to recommend it.

[ Return To The May 2003 Table Of Contents ]



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