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November 2006, Volume 9/ Number 11

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HMP Software �

You�ve Served Your Apprenticeship; You�re Hired!

By Mike Matthews


Since the first white papers and early builds of software grabbed by some eager innovators, we�re now seeing a broader range of HMP (Host Media Processing) products available in the market with better targeted features and stability as the classic software �version 2s� hit the streets from leading vendors.

But first let�s start by reviewing what media processing is about and go on to recap what HMP is and where it fits. A variety of media processing functions need to be taken care of as part of designing and integrating a communications platform, depending on the target application. They range from recording and playing back speech using an appropriate compression or encoding scheme to suit the telephony devices being used, through DTMF recognition to fax transmit and receive. The amount of mathematical processing power required to support each function is very much dependent upon its complexity.

Historically, the only commercially viable method of performing the high number of computations required to run the different algorithms was to use digital signal processors, or DSPs. These devices are still the mainstay of media processing today and, unlike general processors, they have the unique ability to perform both multiply and accumulate functions on a single clock pulse. This efficiency enables high-density designs to be achieved without causing material impacts upon the host processor, which is usually running the main application.

General purpose processors on our PCs and servers seem to creep up in power every year. This point hasn�t been lost on software engineers looking to work on newer versions of algorithms for media processing. While at any point in time we would expect a DSP to outperform a general purpose processor executing like-for-like media processing functions, the more important question is, �Can the general purpose processor support enough channels of media processing required to do the job in the communications system?� This fundamental question can sometimes get lost; it reminds me of a debate I heard comparing two sporty looking high-powered cars � each had some special attributes like road-holding on corners, or raw straight-line speed, but when you boiled it down to a question of can it get me from A to B safely in reasonable time, the simple answer was yes, of course! Few would deny the market trend is for technology to migrate from TDM to IP. In this context it means that no specialist telephony hardware interface is required any more, and the traffic will arrive at the server via a low-cost NIC (News - Alert). Now we�re talking for the first time about having a media processing solution with no specialist hardware! This holds appeal for organizations with strong software application abilities that have found the prospect � or even the experience � of integrating traditional telecoms somewhat daunting. So maybe we�re looking at a slightly different type of developer who will eagerly embrace HMP? So what is the profile of applications being developed with HMP technology? As with any new technology, many were cautious, but they were happy to try the basic functions at modest channel counts. This has led to a number of either embedded IVR functions on the same server as the communication application, or a standalone server configuration to complement an all-new IP system. These key system/PBX (News - Alert)/contact center solutions have typically been in an enterprise environment where maximum local control is achievable and channel counts are frequently below 40 users. This arrangement has allowed a proper exercising of the functionality to everyone�s satisfaction and has allowed feedback to the HMP vendors such that key improvements can be made.

We mustn�t forget that the diffusion of innovation follows a well-documented and reproducible path, so there is a high level of certainty that HMP technologies have staked a firm claim and will see high growth. Initially, this is likely to be at the expense of DSP boards with analog interfaces, which are synonymous with low-density installations. The T1/E1 density board space will be eroded from the low end in due course. But none of this will happen without the main market players taking appropriate steps to listen and act upon customer feedback. This, in itself, can be a challenge for those vendors who take the simplistic view that if a product�s average sell price is below $1,000, then it will be sold via channel partners. The simple alternative is to make the product available on the vendor�s Web site � but is technical support going to be provided in the price of the Webbased product sale? No one is claiming that the technology is an order of magnitude easier to understand than a hardware- based DSP circuit card. Whichever route to market is selected, the vendor has to ensure feedback is managed and support provided appropriately.

Another area worthy of note is the licensing of the HMP product. Given the ease of software distribution, and the inevitable concerns about possible illegal copying, there needs to have been an appropriate amount of consideration given to the balance necessary to protect the vendor and the flexibility needed by the developer and systems integrator. There is an understandable tension in trying to get this right and given that the majority of HMP vendors have a hardware-dominated background, we are witnessing steady improvements across the market. The leading offerings have either an OEM licensing arrangement to enable the developer to embed an appropriate number of channels � at their control � or a software licence key that is generated to match the platform upon which the application is run.

To assist customers who fit the �majority� profile � and that is the stage of the market we are now in � most HMP vendors are offering a free, timelimited version of their product to remove barriers to adoption. With typically 4-6 weeks� time to carry out product evaluations, some vendors even offer free technical or pre-sales support; there is clearly a push to capture the mind share of the development community.

Given that this is IP-based technology, we anticipate an increasingly wide range of devices that HMP will need to be connected to, possibly with different media and compression schemes. In addition to the standard G.711 audio codec, we�re seeing implementations of an interesting range of codecs, including: G.729, G.726, G.723, Speex and iLBC, the Internet low bit-rate codec. The iLBC codec was specifically developed to accommodate the Internet�s �bursty� transmission characteristics, and is used in the widely-deployed Skype (News - Alert) VoIP communications software. It is worth spotting the mixture of audio codecs that cover traditional wired and wireless TDM networks, ensuring a wider applicability for HMP products than at initial launch.

And yes, there still seems to be a solid market need for facsimile � particularly for such sectors as financial services, so support for the T.38 standard is common; this ensures the developer can �tick the box� when asked.

Having touched on audio and fax, let�s not forget video. Those of us watching the newer features coming through on the latest host processors know that every release of silicon brings us �new� and �spectacular� graphics handling and sets the expectation that we should be seeing at least a few channels of video from the HMP products too. Although still in the �early days�, we can nevertheless see the first products becoming available capable of connecting with �like-to-like� video devices; that is to say no transcoding is performed, which would demand intensive processing. What of the future? We can reasonably expect a continuous rise in the number of channels and features that can be supported on a single installation, thus leading the system architect to consider HMP as a serious alternative when making technology selections for more solutions.

As familiarity with the technology increases, both from the HMP vendors and the developers� perspective, we would expect more insights into ways of taking advantage of a software-only architecture that lead to experiencebased enhancements. One such area is likely to be in methods of achieving distribution amongst different servers to provide both additional resilience and a means of scaling a solution. These areas of development should consolidate and enhance the choice for designers to consider incorporating either DSP or HMP technologies in solutions. All in all, you could argue that HMP is just completing its �apprenticeship� and is ready for a prime-time audience. IT

Mike Matthews manages product lifecycles and customer feedback, and is responsible for the positioning of new products at Aculab (News - Alert) ( He manages the link between customers and Aculab�s R&D, oversees Aculab�s product roadmap, and supports the company�s global sales force. A well-known speaker, over the past 25 years he�s also had several roles in telecom industrial consortia responsible for ensuring equipment interoperability.

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